Thang Nguyen, Le Thi Hong, Nguyễn Hoàng Thoan et al.

RSC Advances • 2020

Fabrication of a high-performance room-temperature (RT) gas sensor is important for the future integration of sensors into smart, portable and Internet-of-Things (IoT)-based devices. Herein, we developed a NO 2 gas sensor based on ultrathin MoS 2 nanoflowers with high sensitivity at RT. The MoS 2 flower-like nanostructures were synthesised via a simple hydrothermal method with different growth times of 24, 36, 48, and 60 h. The synthesised MoS 2 nanoflowers were subsequently characterised by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The petal-like nanosheets in pure MoS 2 agglomerated to form a flower-like structure with Raman vibrational modes at 378 and 403 cm -1 and crystallisation in the hexagonal phase. The specific surface areas of the MoS 2 grown at different times were measured by using the Brunauer-Emmett-Teller method. The largest specific surface area of 56.57 m 2 g -1 was obtained for the MoS 2 nanoflowers grown for 48 h. This sample also possessed the smallest activation energy of 0.08 eV. The gas-sensing characteristics of sensors based on the synthesised MoS 2 nanostructures were investigated using oxidising and reducing gases, such as NO 2 , SO 2 , H 2 , CH 4 , CO and NH 3 , at different concentrations and at working temperatures ranging from RT to 150 °C. The sensor based on the MoS 2 nanoflowers grown for 48 h showed a high gas response of 67.4% and high selectivity to 10 ppm NO 2 at RT. This finding can be ascribed to the synergistic effects of largest specific surface area, smallest crystallite size and lowest activation energy of the MoS 2 -48 h sample among the samples. The sensors also exhibited a relative humidity-independent sensing characteristic at RT and a low detection limit of 84 ppb, thereby allowing their practical application to portable IoT-based devices.

Ghulamullah Maitlo, Imran Ali, Hubdar Ali Maitlo et al.

Sustainability • 2022

Plastic waste accumulation has been recognized as one of the most critical challenges of modern societies worldwide. Traditional waste management practices include open burning, landfilling, and incineration, resulting in greenhouse gas emissions and economic loss. In contrast, emerging techniques for plastic waste management include microwave-assisted conversion, plasma-assisted conversion, supercritical water conversion, and photo reforming to obtain high-value products. Problems with poorly managed plastic waste are particularly serious in developing countries. This review article examines the emerging strategies and production of various high-value-added products from plastic waste. Additionally, the uses of plastic waste in different sectors, such as construction, fuel production, wastewater treatment, electrode materials, carbonaceous nanomaterials, and other high-value-added products are reviewed. It has been observed that there is a pressing need to utilize plastic waste for a circular economy and recycling for different value-added products. More specifically, there is limited knowledge on emerging plastic waste conversion mechanisms and efficiency. Therefore, this review will help to highlight the negative environmental impacts of plastic waste accumulation and the importance of modern techniques for waste management.

Qinrong He, Joe Briscoe

ACS Applied Materials & Interfaces • 2024

Piezoelectric energy harvesters have gained significant attention in recent years due to their ability to convert ambient mechanical vibrations into electrical energy, which opens up new possibilities for environmental monitoring, asset tracking, portable technologies and powering remote "Internet of Things (IoT)" nodes and sensors. This review explores various aspects of piezoelectric energy harvesters, discussing the structural designs and fabrication techniques including inorganic-based energy harvesters (i.e., piezoelectric ceramics and ZnO nanostructures) and organic-based energy harvesters (i.e., polyvinylidene difluoride (PVDF) and its copolymers). The factors affecting the performance and several strategies to improve the efficiency of devices have been also explored. In addition, this review also demonstrated the progress in flexible energy harvesters with integration of flexibility and stretchability for next-generation wearable technologies used for body motion and health monitoring devices. The applications of the above devices to harvest various forms of mechanical energy are explored, as well as the discussion on perspectives and challenges in this field.

Uthpala Garusinghe, Vikram Singh Raghuwanshi, Warren Batchelor et al.

Scientific Reports • 2018

Novel water resistant photocatalytic composites of microfibrillated cellulose (MFC)-polyamide-amine-epichlorohydrin (PAE)-TiO 2 nanoparticles (NPs) were prepared by a simple two-step mixing process. The composites produced are flexible, uniform, reproducible and reusable; they can readily be removed from the pollutant once used. Small amount of TiO 2 NPs are required for the loaded composites to exhibit a remarkable photocatalytic activity which is quantified here as achieving at least 95% of methyl orange degradation under 150 min of UV light irradiation for the composite with best combination. The cellulose network combined with PAE strongly retains NPs and hinders their release in the environment. PAE dosage (10 and 50 mg/g MFC) controls the NP retention in the cellulose fibrous matrix. As TiO 2 content increases, the photocatalytic activity of the composites levels off to a constant; this is reached at 2wt% TiO 2 NPs for 10 mg/g PAE and 20wt% for 50 mg/g PAE. SEM and SAXS analysis confirms the uniform distribution of NPs and their formation of aggregates in the cellulose fibre network. These economical and water resistant photocatalytic paper composites made by a simple, robust and easily scalable process are ideal for applications such as waste water treatment where efficiency, reusability and recyclability are important.

Xiaohui Tang, Pierre-Antoine Haddad, Nathalie Mager et al.

Scientific Reports • 2019

Graphene decorated by palladium (Pd) nanoparticles has been investigated for hydrogen sensor applications. The density of Pd nanoparticles is critical for the sensor performance. We develop a new chemical method to deposit high-density, small-size and uniformly-distributed Pd nanoparticles on graphene. With this method, Pd precursors are connected to the graphene by π-π bonds without introducing additional defects in the hexagonal carbon lattice. Our method is simple, cheap, and compatible with complementary metal-oxide semiconductor (CMOS) technology. This method is used to fabricate hydrogen sensors on 3-inch silicon wafers. The sensors show high performance at room temperature. Particularly, the sensors present a shorter recovery time under light illumination. The sensing mechanism is explained and discussed. The proposed deposition method facilitates mass fabrication of the graphene sensors and allows integration with CMOS circuits for practical applications.

Zhongshan Chen, Yang Li, Yawen Cai et al.

Carbon Research • 2023

Abstract With the fast development of agriculture, industrialization and urbanization, large amounts of different (in)organic pollutants are inevitably discharged into the ecosystems. The efficient decontamination of the (in)organic contaminants is crucial to human health and ecosystem pollution remediation. Covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) have attracted multidisciplinary research interests because of their outstanding physicochemical properties like high stability, large surface areas, high sorption capacity or catalytic activity. In this review, we summarized the recent works about the elimination/extraction of organic pollutants, heavy metal ions, and radionuclides by MOFs and COFs nanomaterials through the sorption-catalytic degradation for organic chemicals and sorption-catalytic reduction-precipitation-extraction for metals or radionuclides. The interactions between the (in)organic pollutants and COFs/MOFs nanomaterials at the molecular level were discussed from the density functional theory calculation and spectroscopy analysis. The sorption of organic chemicals was mainly dominated by electrostatic attraction, π-π interaction, surface complexation and H-bonding interaction, whereas the sorption of radionuclides and metal ions was mainly attributed to surface complexation, ion exchange, reduction and incorporation reactions. The porous structures, surface functional groups, and active sites were important for the sorption ability and selectivity. The doping or co-doping of metal/nonmetal, or the incorporation with other materials could change the visible light harvest and the generation/separation of electrons/holes (e − /h + ) pairs, thereby enhanced the photocatalytic activity. The challenges for the possible application of COFs/MOFs nanomaterials in the elimination of pollutants from water were described in the end.

Wenxi Huang, Qiongling Ding, Hao Wang et al.

Nature Communications • 2023

Timely and remote biomarker detection is highly desired in personalized medicine and health protection but presents great challenges in the devices reported so far. Here, we present a cost-effective, flexible and self-powered sensing device for H 2 S biomarker analysis in various application scenarios based on the structure of galvanic cells. The sensing mechanism is attributed to the change in electrode potential resulting from the chemical adsorption of gas molecules on the electrode surfaces. Intrinsically stretchable organohydrogels are used as solid-state electrolytes to enable stable and long-term operation of devices under stretching deformation or in various environments. The resulting open-circuit sensing device exhibits high sensitivity, low detection limit, and excellent selectivity for H 2 S. Its application in the non-invasive halitosis diagnosis and identification of meat spoilage is demonstrated, emerging great commercial value in portable medical electronics and food security. A wireless sensory system has also been developed for remote H 2 S monitoring with the participation of Bluetooth and cloud technologies. This work breaks through the shortcomings in the traditional chemiresistive sensors, offering a direction and theoretical foundation for designing wearable sensors catering to other stimulus detection requirements.

Mehrdad Khatami, Hajar Q. Alijani, Meysam Soltani Nejad et al.

Applied Sciences • 2018

Among an array of hybrid nanoparticles, core-shell nanoparticles comprise of two or more materials, such as metals and biomolecules, wherein one of them forms the core at the center, while the other material/materials that were located around the central core develops a shell. Core-shell nanostructures are useful entities with high thermal and chemical stability, lower toxicity, greater solubility, and higher permeability to specific target cells. Plant or natural products-mediated synthesis of nanostructures refers to the use of plants or its extracts for the synthesis of nanostructures, an emerging field of sustainable nanotechnology. Various physiochemical and greener methods have been advanced for the synthesis of nanostructures, in contrast to conventional approaches that require the use of synthetic compounds for the assembly of nanostructures. Although several biological resources have been exploited for the synthesis of core-shell nanoparticles, but plant-based materials appear to be the ideal candidates for large-scale green synthesis of core-shell nanoparticles. This review summarizes the known strategies for the greener production of core-shell nanoparticles using plants extract or their derivatives and highlights their salient attributes, such as low costs, the lack of dependence on the use of any toxic materials, and the environmental friendliness for the sustainable assembly of stabile nanostructures.

Yu-Sung Chang, Feng-Kuan Chen, Du‐Cheng Tsai et al.

Scientific Reports • 2021

In this study, we use nitrogen-doped to improving the gas-sensing properties of reduced graphene oxide. Graphene oxide was prepared according to a modified Hummers' method and then nitrogen-doped reduced graphene oxide (N-rGO) was synthesized by a hydrothermal method using graphene oxide and NH 4 OH as precursors. The rGO is flat and smooth with a sheet-like morphology while the N-rGO exhibits folded morphology. This type of folding of the surface morphology can increase the gas sensitivity. The N-rGO and the rGO sensors showed n-type and p-type semiconducting behaviors in ambient conditions, respectively, and were responsive to low concentrations of NO gases (< 1000 ppb) at room temperature. The gas-sensing results showed that the N-rGO sensors could detect NO gas at concentrations as low as 400 ppb. The sensitivity of the N-rGO sensor to 1000 ppb NO (1.7) is much better than that of the rGO sensor (0.012). Compared with pure rGO, N-rGO exhibited a higher sensitivity and excellent reproducibility.

Jitendra Wankar, Niranjan G. Kotla, Sonia Gera et al.

Advanced Functional Materials • 2020

Abstract This Review is an overview of the unique characteristics of cyclodextrin in forming an inclusion complex via host–guest noncovalent interactions. The modification of cyclodextrin advances its application as a pharmaceutical solubilizer, fabrication of functional molecular machines such as polyrotaxane, polypseudorotaxane, and polycatenanes and grafting of cyclodextrin with different linear, branched chain polymers. The different stimuli‐based supramolecular assemblies involving cyclodextrin as a key mediator with linked triggering responses on payload release is highlighted. In addition, the applications of cyclodextrin in diagnostic imaging and medical devices is briefly demonstrated. Cyclodextrin is a relatively low cost, biocompatible, biodegradable, and highly explored material with low toxicity for drug formulation, drug delivery, and wide varieties of other biomedical applications such as those in medical devices fabrication, biosensor, tissue engineering, and bio‐imaging. The toxicological profile of cyclodextrin is well established and safe for human consumption in food and medicine.

Karumbaiah N. Chappanda, Osama Shekhah, Omar Yassine et al.

Sensors and Actuators B Chemical • 2017

Wenfang Zhai, Yuanyuan Ma, Dong Chen et al.

InfoMat • 2022

Abstract Developing new methodologies to produce clean and renewable energy resources is pivotal for carbon‐neutral initiatives. Hydrogen (H 2 ) is considered as an ideal energy resource due to its nontoxic, pollution‐free, high utilization rate, and high calorific combustion value. Electrolysis of water driven by the electricity generated from renewable and clean energy sources (e.g., solar energy, wind energy) to produce hydrogen attracts great efforts for hydrogen production with high purity. Recently, the breakthrough of the catalyst activity limit for the hydrogen evolution reaction (HER) catalysts has received extensive attention. Comparatively, fewer reviews have focused on the long‐term stability of HER catalysts, which is indeed decisive for large‐scale electrolytic industrialization. Therefore, a systematic summary concentrated on the durability of HER electrocatalysts would provide a fundamental understanding of the electrocatalytic performance for practical applications and offer new opportunities for the rational design of the highly performed HER electrocatalysts. This review summarizes the research progress toward the HER stability of precious metals, transition metals, and metal‐free electrocatalysts in the past few years. It discusses the challenges in the stability of HER electrocatalysts and the future perspectives. We anticipate that it would provide a valuable basis for designing robust HER electrocatalysts. image

Huiling Tai, Zhen Yuan, Weijian Zheng et al.

Nanoscale Research Letters • 2016

ZnO nanoparticles and graphene oxide (GO) thin film were deposited on gold interdigital electrodes (IDEs) in sequence via simple spraying process, which was further restored to ZnO/reduced graphene oxide (rGO) bilayer thin film by the thermal reduction treatment and employed for ammonia (NH3) detection at room temperature. rGO was identified by UV-vis absorption spectra and X-ray photoelectron spectroscope (XPS) analyses, and the adhesion between ZnO nanoparticles and rGO nanosheets might also be formed. The NH3-sensing performances of pure rGO film and ZnO/rGO bilayer films with different sprayed GO amounts were compared. The results showed that ZnO/rGO film sensors exhibited enhanced response properties, and the optimal GO amount of 1.5 ml was achieved. Furthermore, the optimal ZnO/rGO film sensor showed an excellent reversibility and fast response/recovery rate within the detection range of 10-50 ppm. Meanwhile, the sensor also displayed good repeatability and selectivity to NH3. However, the interference of water molecules on the prepared sensor is non-ignorable; some techniques should be researched to eliminate the effect of moisture in the further work. The remarkably enhanced NH3-sensing characteristics were speculated to be attributed to both the supporting role of ZnO nanoparticles film and accumulation heterojunction at the interface between ZnO and rGO. Thus, the proposed ZnO/rGO bilayer thin film sensor might give a promise for high-performance NH3-sensing applications.

Mohamed Rachid Tchalala, Prashant M. Bhatt, Karumbaiah N. Chappanda et al.

Nature Communications • 2019

Conventional SO 2 scrubbing agents, namely calcium oxide and zeolites, are often used to remove SO 2 using a strong or irreversible adsorption-based process. However, adsorbents capable of sensing and selectively capturing this toxic molecule in a reversible manner, with in-depth understanding of structure-property relationships, have been rarely explored. Here we report the selective removal and sensing of SO 2 using recently unveiled fluorinated metal-organic frameworks (MOFs). Mixed gas adsorption experiments were performed at low concentrations ranging from 250 p.p.m. to 7% of SO 2 . Direct mixed gas column breakthrough and/or column desorption experiments revealed an unprecedented SO 2 affinity for KAUST-7 (NbOFFIVE-1-Ni) and KAUST-8 (AlFFIVE-1-Ni) MOFs. Furthermore, MOF-coated quartz crystal microbalance transducers were used to develop sensors with the ability to detect SO 2 at low concentrations ranging from 25 to 500 p.p.m.

Nadia Garino, Andrea Lamberti, Stefano Stassi et al.

Electrochimica Acta • 2019

Nahid Torabi, Xinkai Qiu, Manuel López‐Ortiz et al.

Langmuir • 2021

This paper describes the fabrication of microfluidic devices with a focus on controlling the orientation of photosystem I (PSI) complexes, which directly affects the performance of biophotovoltaic devices by maximizing the efficiency of the extraction of electron/hole pairs from the complexes. The surface chemistry of the electrode on which the complexes assemble plays a critical role in their orientation. We compared the degree of orientation on self-assembled monolayers of phenyl-C 61 -butyric acid and a custom peptide on nanostructured gold electrodes. Biophotovoltaic devices fabricated with the C 61 fulleroid exhibit significantly improved performance and reproducibility compared to those utilizing the peptide, yielding a 1.6-fold increase in efficiency. In addition, the C 61 -based devices were more stable under continuous illumination. Our findings show that fulleroids, which are well-known acceptor materials in organic photovoltaic devices, facilitate the extraction of electrons from PSI complexes without sacrificing control over the orientation of the complexes, highlighting this combination of traditional organic semiconductors with biomolecules as a viable approach to coopting natural photosynthetic systems for use in solar cells.

Viktorija Reinikovaite, Šarūnas Žukauskas, Rokas Žalnėravičius et al.

Biosensors • 2022

The development of microbial fuel cells based on electro-catalytic processes is among the novel topics, which are recently emerging in the sustainable development of energetic systems. Microbial fuel cells have emerged as unique biocatalytic systems, which transform the chemical energy accumulated in renewable organic fuels and at the same time reduce pollution from hazardous organic compounds. However, not all microorganisms involved in metabolic/catalytic processes generate sufficient redox potential. In this research, we have assessed the applicability of the microorganism Rhizobium anhuiense as a catalyst suitable for the design of microbial fuel cells. To improve the charge transfer, several redox mediators were tested, namely menadione, riboflavin, and 9,10-phenanthrenequinone (PQ). The best performance was determined for a Rhizobium anhuiense -based bio-anode mediated by menadione with a 0.385 mV open circuit potential and 5.5 μW/cm 2 maximal power density at 0.35 mV, which generated 50 μA/cm 2 anode current at the same potential.

Tong Liu

Sustainability • 2022

Glucose is a ubiquitous source of energy for nearly all living things, and glucose fuel cells (GFCs) are regarded as a sustainable power source because glucose is renewable, easily available, cheap, abundant, non-toxic and easy-to-store. Numerous efforts have been devoted to developing and improving GFC performance; however, there is still no commercially viable devices on the market. Membranes play an essential role in GFCs for the establishment of a suitable local microenvironment, selective ion conducting and prevention of substrate crossover. However, our knowledge on them is still limited, especially on how to achieve comparable efficacy with that of a biological system. This review article provides the first brief overview on these aspects, particularly keeping in sight the research trends, current challenges, and the future prospects. We aim to bring together literature analysis and technological discussion on GFCs and membranes by using bibliometrics, and provide new ideas for researchers in this field to overcome challenges on developing high-performance GFCs.

Jirawan Monkrathok, Pattanaphong Janphuang, Somphong Suphachiaraphan et al.

Biosensors • 2024

We designed and optimized a glucose biosensor system based on a screen-printed electrode modified with the NAD-GDH enzyme. To enhance the electroactive surface area and improve the electron transfer efficiency, we introduced graphene oxide (GO) and ferrocene-modified linear poly(ethylenimine) (LPEI-Fc) onto the biosensor surface. This strategic modification exploits the electrostatic interaction between graphene oxide, which possesses a negative charge, and LPEI-Fc, which is positively charged. This interaction results in increased catalytic current during glucose oxidation and helps improve the overall glucose detection sensitivity by amperometry. We integrated the developed glucose sensor into a flow injection (FI) system. This integration facilitates a swift and reproducible detection of glucose, and it also mitigates the risk of contamination during the analyses. The incorporation of an FI system improves the efficiency of the biosensor, ensuring precise and reliable results in a short time. The proposed sensor was operated at a constant applied potential of 0.35 V. After optimizing the system, a linear calibration curve was obtained for the concentration range of 1.0-40 mM (R 2 = 0.986). The FI system was successfully applied to determine the glucose content of a commercial sports drink.

Tsai Garcia‐Perez, Shouzhen Hu, Youngho Wee et al.

Frontiers in Chemistry • 2019

Biofuel cell (BFC) electrodes are typically manufactured by combining enzymes that act as catalysts with conductive carbon nanomaterials in a form of enzyme-nanocomposite. However, a little attention has been paid to effects of the carbon nanomaterials' structural properties on the electrochemical performances of the enzyme-nanocomposites. This work aims at studying the effects of surface and bulk properties of carbon nanomaterials with different degrees of graphitization on the electrochemical performances of glucose oxidase (GOx)-nanocomposites produced by immobilizing GOx within a network of carbon nanopaticles. Two types of carbon nanomaterials were used: graphitized mesoporous carbon (GMC) and purified mesoporous carbon (PMC). Graphitization index, surface functional groups, hydrophobic properties, and rate of aggregation were measured for as-received and acid-treated GMC and PMC samples by using Raman spectrometry, X-ray photoelectron spectroscopy ( XPS), contact angle measurement, and dynamic light scattering (DLS), respectively. In addition to these physical property characterizations, the enzyme loading and electrochemical performances of the GOx-nanocomposites were studied via elemental analysis and cyclic voltammetry tests, respectively. We also fabricated BFCs using our GOx-nanocomposite materials as the enzyme anodes, and tested their performances by obtaining current-voltage (IV) plots. Our findings suggest that the electrochemical performance of GOx-nanocomposite material is determined by the combined effects of graphitization index, electrical conductivity and surface chemistry of carbon nanomaterials.

Muhammad Syafiq Mohd Razib, Wahhida Latip, Jahwarhar Izuan Abdul Rashid et al.

Journal of Chemistry • 2021

Enzymatic detection of organophosphate (OP) compounds can be tailored using highly sensitive and selective enzymes in the development of biosensors. Previously, mutant (YT) phosphotriesterase (PTE) was reported to efficiently hydrolyze Sp and Rp enantiomers of phosphotriester. This study reports the use of phosphotriesterase mutant YT (YT-PTE) immobilized onto reduced graphene oxide (rGO) and fabricated onto a screen-printed carbon electrode (SPCE) for electrochemical detection of OP compounds. Immobilization of YT-PTE onto rGO was secured using N-hydroxysuccinimide (NHS) and N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide (EDC) cross-linker, and the resulting immobilized enzyme was able to retain up to 90% of its activity. Electrochemical analysis of the SPCE/rGO/YT-PTE showed detection of paraoxon in a linear range of 1 mM–0.005 μM with its limit of detection as low as 0.11 μM. SPCE/rGO/YT-PTE exhibited high selectivity towards paraoxon and parathion and have good reproducibility. Furthermore, detection of paraoxon was also possible in a real water sample with only minor interferences.

Maha Khan, Inamuddin Inamuddin

Scientific Reports • 2024

Enzymatic biofuel cells (EBFCs) hold tremendous potential to power biomedical devices, biosensors, and bioelectronics. Unlike conventional toxic batteries, these electrochemical devices are biocompatible, harnessing energy from physiological fluids and producing usable electrical energy. But the commercialization of EBFCs is limited by the low operational stability, limited power output and poor electron transport efficiency of the enzymatic electrodes. In this study, a novel bioanode exhibiting a high electron transfer ability and long-term stability was fabricated. For the preparation of the anode, surfactant-assisted polypyrrole (PPy) was electrochemically co-deposited on a platinum wire with the simultaneous entrapment of vitamin K 3 (VK 3 ) and GOx (glucose oxidase) in the PPy matrix. Herein, conducting PPy acts as an electron transfer enhancer and provides appropriate electrical communication between the active site of the enzyme glucose oxidase (GOx) and the electrode surface. Biocompatible redox mediator vitamin K 3 was employed as an electron transfer mediator to shuttle electrons between the oxidized fuel glucose and surface of the electrode in the electrochemical cell. The electrical conductivity of PPy was measured using the four-probe technique of conductivity measurement of semiconductors. The morphological characterization of as-synthesized anode (PPy/CTAB/VK 3 /GOx) was performed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical characterization was studied by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. It was observed that the room-temperature conductivity of PPy lies in the semiconducting range and it also shows good stability on exposure to laboratory air, making it a promising material to provide electrical contact. The study developed a bioanode producing a modest current density of 6.35 mA cm -2 in 20 mM glucose solution. The stability, current output and ease of manufacturing process of the electrode make it particularly suitable for employment in biofuel cell applications.

Xiaomei Yan, Su Ma, Jing Tang et al.

Electrochimica Acta • 2021

Direct electrochemical electron transfer (DET) of oxidoreductases has attracted increasing attention in pure and applied bioelectrochemistry (e.g. biosensors and biofuel cells) over the last decades. We report here a systematic study of DET-type bioelectrocatalysis of the membrane-bound redox enzyme fructose dehydrogenase (FDH, Gluconobacter sp.), on variable-length and variably terminated thiol self-assembled monolayers (SAMs) both on Au(111) and nanoporous gold (NPG) electrodes. FDH on Au(111) modified by short-chain moderately hydrophilic 2-mercaptoethanol (BME) SAMs exhibits the highest DET activities and largest DET-capable fraction. Fitting of theoretical polarization curves to the data and homology modeling/docking of FDH offer further mechanistic insight. The dependence of the DET efficiency of FDH on the length and differently terminated carbon chain is systematically presented. The decreased DET rate with increasing chain length is associated with increasingly unfavourable long-range electron tunnelling, and not with lowered enzyme loading. The porous structure of NPG is favorable for FDH bioelectrocatalysis by improving both efficient enzyme orientation and operational stability. Overall, our study maps systematically the controlled local environmental structural flexibility of the Au/SAM/enzyme/solution interface, a paradigm for thiol modified surfaces in biosensors and bioelectronics.

Yuan Liu, Luyan Wang, Xue Ni et al.

Materials • 2020

An ultra-highly efficient Graphene Oxide/TiO 2 /Bentonite (GO/TiO 2 /Bent) sponge was synthesized using an in situ hydrothermal method. GO/TiO 2 /Bent sponge with a GO mass concentration of 10% exhibited the highest treatment efficiency of methylene blue (MB), combining adsorption and photocatalytic degradation, and achieved a maximum removal efficiency of 100% within about 70 min. To further prove the ultra-high removal capacity of the sponge, the concentration of MB in water increased to ten times the original concentration. At so high a MB concentration, the removal rate was still as high as 80% in 90 min. The photocatalytic mechanism of GO/TiO 2 /Bent sponge was discussed through XPS, PL and radicals quenching experiments. Here Bent can immobilize TiO 2 and react with a photo-generated hole to increase the amount of hydroxyl radical; effectively enhancing the degradation of MB.GO sponge enlarges the sensitivity range of TiO 2 to visible light by increasing the charge separation of TiO 2 and reducing the recombination of photo-generated electron-hole pairs. Additionally, GO sponge with an interconnected porous structure provides an effective platform to immobilize TiO 2 /bent and makes them be easily recovered. The as-prepared sponge develops a simple and cost-effective strategy to realize the ultra-highly efficient treatment of dyes in wastewater.

Zheng Chen, Zheng Chen, Guowen Dong et al.

Chemical Engineering Journal • 2019

Melesse Tadesse, Yun Liu

Catalysts • 2025

Enzymes, as nature’s precision biocatalysts, hold transformative potential across industrial, environmental, and biomedical sectors. However, their instability, solvent sensitivity, and limited reusability in their free form necessitate advanced immobilization strategies to enhance their robustness and scalability. This review critically examines cutting-edge advancements in enzyme immobilization, focusing on the integration of artificial intelligence (AI), novel nanomaterials, and dynamic carrier systems to overcome the traditional limitations of mass transfer, enzyme leakage, and cost inefficiency. Key innovations such as metal–organic frameworks (MOFs), magnetic nanoparticles, self-healing hydrogels, and 3D-printed scaffolds are highlighted for their ability to optimize enzyme orientation, stability, and catalytic efficiency under extreme conditions. Moreover, AI-driven predictive modeling and machine learning emerge as pivotal tools for rationalizing nanomaterial synthesis, multi-enzyme cascade design, and toxicity assessment, while microfluidic systems enable precise biocatalyst fabrication. This review also explores emerging carrier-free strategies, including cross-linked enzyme aggregates (CLEAs) and DNA-directed immobilization, which minimize diffusion barriers and enhance substrate affinity. Despite progress, challenges persist in regards to eco-friendly nanomaterial production, industrial scalability, and real-world application viability. Future directions emphasize sustainable hybrid material design, AI-aided lifecycle assessments, and interdisciplinary synergies between synthetic biology, nanotechnology, and data analytics. By connecting laboratory innovation with industrial needs, this work provides a forward-thinking framework to harness immobilized enzymes for achieving global sustainability goals, particularly in bioremediation, bioenergy, and precision medicine.

Shenghan Yan, Changqing Liu, Xingguang Luο et al.

Chemical Engineering Journal • 2024

Junyi Yin, Shaolei Wang, Aiden Di Carlo et al.

Med-X • 2023

Abstract Merging electronics with textiles has become an emerging trend since textiles hold magnificent wearing comfort and user-friendliness compared with conventional wearable bioelectronics. Smart textiles can be effectively integrated into our daily wearing to convert on-body biomechanical, biochemical, and body heat energy into electrical signals for long-term, real-time monitoring of physiological states, showing compelling medical and economic benefits. This review summarizes the current progress in self-powered biomonitoring textiles along three pathways: biomechanical, body heat, and biochemical energy conversion. Finally, it also presents promising directions and challenges in the field, as well as insights into future development. This review aims to highlight the frontiers of smart textiles for self-powered biomonitoring, which could contribute to revolutionizing our traditional healthcare into a personalized model. Graphical Abstract Self-powered biomonitoring textiles via biomechanical, body heat, and biochemical energy conversion are discussed in this work. Platform technologies, including piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs), and magnetoelastic generators (MEGs) for biomechanical energy conversion, thermoelectric generators (TEGs) for boy heat energy conversion, and biofuel cells (BFCs) for biochemical energy conversion, are systematically introduced and discussed in a textile form. Working in a self-powered manner with greatly improved wearing comfort, the smart biomonitoring textiles pave a compelling road to personalized healthcare.

Tasnim Aisya Mahmuelee Torlaema, Mohamad Nasir Mohamad Ibrahim, Akil Ahmad et al.

Processes • 2022

Microbial fuel cell (MFC) technology has captured the scientific community’s attention in recent years owing to its ability to directly transform organic waste into electricity through electrochemical processes. Currently, MFC systems faces a number of barriers, with one of the most significant being the lack of organic substrate to provide enough energy for bacterial growth and activity. In the current work, rotten rice was utilized as an organic substrate to boost bacterial activity to produce more energy and break down the organic pollutant hydroquinone in an effort to improve the performance of MFCs. There are only a few studies that considered the waste as an organic substrate and simultaneously degraded the organic pollutant vis-à-vis MFCs. The oxidation of glucose derived from rotten rice generated electrons that were transported to the anode surface and subsequently flowed through an external circuit to the cathode, where they were used to degrade the organic pollutant hydroquinone. The results were consistent with the MFC operation, where the 168-mV voltage was generated over the course of 29 days with a 1000 Ω external resistance. The maximum power and current densities were 1.068 mW/m2 and 123.684 mA/m2, respectively. The hydroquinone degradation was of 68%. For the degradation of organic pollutants and the production of energy, conductive pili-type bacteria such as Lacticaseibacillus, Pediococcus acidilactici and Secundilactobacillus silagincola species were identified during biological characterization. Future recommendations and concluding remarks are also included.

Lyubov S. Kuznetsova, Vyacheslav A. Arlyapov, Olga A. Kamanina et al.

Polymers • 2022

Electropolymerized neutral red, thionine, and aniline were used as part of hybrid nanocomposite conductive polymers, to create an amperometric reagent-less biosensor for glucose determination. The structure of the obtained polymers was studied using infrared (IR) spectroscopy and scanning electron microscopy. Electrochemical characteristics were studied by cyclic voltammetry and impedance spectroscopy. It was shown that, from the point of view of both the rate of electron transfer to the electrode, and the rate of interaction with the active center of glucose oxidase (GOx), the most promising is a new nanocomposite based on poly(neutral red) (pNR) and thermally expanded graphite (TEG). The sensor based on the created nanocomposite material is characterized by a sensitivity of 1000 ± 200 nA × dm 3 /mmol; the lower limit of the determined glucose concentrations is 0.006 mmol/L. The glucose biosensor based on this nanocomposite was characterized by a high correlation (R 2 = 0.9828) with the results of determining the glucose content in human blood using the standard method. Statistical analysis did not reveal any deviations of the results obtained using this biosensor and the reference method. Therefore, the developed biosensor can be used as an alternative to the standard analysis method and as a prototype for creating sensitive and accurate glucometers, as well as biosensors to assess other metabolites.

Hong Lü, Teng Zhang, Yang Zhou et al.

Scientific Reports • 2019

The effect of a 2-aminoanthraquinone-graphene oxide (AQ-GO) composite on the anaerobic dechlorination and degradation of chloroanilines by an enriched bacterial consortium was investigated. The results showed that the maximal degradation efficiency of 20 mg/L 2-chloroaniline (2-CA) reached 91.4% at a dose of 20 mg/L AQ-GO in 30 d. Moreover, the pseudo-first-order rate constant of 2-CA degradation in the AQ-GO-mediated system was 2.9-fold higher than those in AQ- and GO-mediated systems alone. During this process, a synergetic effect between AQ and GO was observed, which was attributed to the increased intracellular and extracellular electron transfer pathways. GC-MS analysis showed that 2-CA could be degraded to hexanoic acid and ultimately mineralized to CO 2 . Illumina MiSeq sequencing revealed that additional AQ-GO significantly increased the relative abundance of Firmicutes. Further analysis showed that the populations of the genera Oscillospira, unclassified Lactobacillales, unclassified Veillonellaceae and Ruminococcus exhibited positive correlations with the rate constant of 2-CA degradation and the dehydrogenase activity of bacterial consortium. These findings indicated that AQ-GO promoted the enrichment of functional bacteria and increased the bacterial activity, resulting in the enhanced dechlorination and degradation of 2-chloroaniline.

Segundo Rojas-Flores, Renny Nazario-Naveda, Evelyn Abanto Paredes et al.

The Open Biotechnology Journal • 2020

Background: Microbial Fuel Cells (MFCs) are promising devices that enable the employment of discarded organic matter, typically gathered around food supply chains, to generate electricity. Aims: In this work, low-cost MFCs in the absence of a proton exchange membrane were fabricated. Methods: They were built on polyvinyl chloride (PVC) plastic tubes with square acrylic sheets at the ends serving as a framework of anode/cathode chambers and using zinc (Zn) and copper (Cu) metals as electrodes. Tomatoes, onions, and potatoes were used as substrates in MFCs and monitored for 21 days. Variables of interest such as voltage, current, pH, and volume were measured through a 100 Ω resistor. Results: The voltage measurements for the onion-based cell showed an upward trend that reaches a peak of 1.01 volts on the last day. Moreover, the greatest current generation was observed in onion cells, in which the current gradually increases from 10.2 to 24.7 mA on the last day. On the other hand, in all substrates, pH ranged from 7.5 and 10, which indicates the slightly alkaline behavior of the solutions. Conclusion: A reduction in the volume of the substrate was observed during the voltage generation. Finally, during the last day, MFCs were connected in series which allowed for the successful generation of 2.35 volts, and consequently, illumination of LED light.

GABRIEL G. DE TOLEDO, Víctor H. Toledo, Alexandre J. C. Lanfredi et al.

Anais da Academia Brasileira de Ciências • 2020

The development of self-disinfectant devices is highly needed to prevent and control infections, mainly caused by virus. In the past years, coronaviruses have been a threat to humanity, causing severe epidemics of respiratory infections such as severe acute respiratory syndrome (SARS), in 2003, and Middle East respiratory syndrome (MERS) in 2012, and presently the SARS-CoV2 is causing the COVID-19 pandemic. Previous studies have demonstrated that surface contamination play a significant role in the spreading of viruses. These studies demonstrated that the production of highly reactive species by copper alloys contributes to rapid elimination of viruses. Nanostructured materials such as semiconductors TiO2, Co3O4 CuO, NiO, and TiO2, and silver nanoparticles can decrease the virus viability on the surfaces when associated with polymers and textiles, especially in conditions of light exposure. In addition, graphene oxide is rising as a promising material for inactivation of viruses due to its capacity of destroying the viral envelope and capsid. The virucidal property of these materials can be enhanced by increasing their functionalization with photosensitizers. The present mini-review brings subsidies for the development of new advanced self-disinfectant materials that can be used in the manufacture of gloves, masks, and a variety of other devices.

Asta Kausaite‐Minkstimiene, Algimantas Kaminskas, Galina Gayda et al.

Biosensors • 2024

This paper describes the study of an amperometric glucose biosensor based on an enzymatic biofuel cell consisting of a bioanode and a biocathode modified with the same enzyme-glucose oxidase (GOx). A graphite rod electrode (GRE) was electrochemically modified with a layer of Prussian blue (PB) nanoparticles embedded in a poly(pyrrole-2-carboxylic acid) (PPCA) shell, and an additional layer of PPCA and was used as the cathode. A GRE modified with a nanocomposite composed of poly(1,10-phenanthroline-5,6-dione) (PPD) and gold nanoparticles (AuNPs) entrapped in a PPCA shell was used as an anode. Both electrodes were modified with GOx by covalently bonding the enzyme to the carboxyl groups of PPCA. The developed biosensor exhibited a wide linear range of 0.15-124.00 mM with an R 2 of 0.9998 and a sensitivity of 0.16 μA/mM. The limit of detection (LOD) and quantification (LOQ) were found to be 0.07 and 0.23 mM, respectively. The biosensor demonstrated exceptional selectivity to glucose and operational stability throughout 35 days, as well as good reproducibility, repeatability, and anti-interference ability towards common interfering substances. The studies on human serum demonstrate the ability of the newly designed biosensor to determine glucose in complex real samples at clinically relevant concentrations.

Brandon G. Roy, Julia L. Rutherford, Anna E. Weaver et al.

Biosensors • 2020

Glutathione is an important biological molecule which can be an indicator of numerous diseases. A method for self-powered detection of glutathione levels in solution has been developed using an enzymatic biofuel cell. The device consists of a glucose oxidase anode and a bilirubin oxidase cathode. For the detection of glutathione, the inhibition of bilirubin oxidase leads to a measurable decrease in current and power output. The reported method has a detection limit of 0.043 mM and a linear range up to 1.7 mM. Being able to detect a range of concentrations can be useful in evaluating a patient's health. This method has the potential to be implemented as a quick, low-cost alternative to previously reported methods.

Tariq Altalhi, Amine Mezni, Mohammed A. Amin et al.

Polymers • 2022

This study aims to design a new nanocomposite as a supporting material for wiring the enzyme to develop a bioanode in the enzymatic biofuel cell (EBFC). In this work, polyaniline-based nanocomposite was synthesized by in situ polymerization of aniline monomer. The zeta potential study of the nanofillers was carried out, which reveals the interaction between the nanofillers. The synthesized nanocomposite (MWCNT/ZnS/AgNWs/PANI) was characterized by analytical techniques, such as Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD). Furthermore, the surface morphology and the in-depth information of the synthesized nanocomposite were displayed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. In addition, the as-synthesized nanocomposite and the designed bioanode underwent the electrochemical assessment using different electrochemical techniques such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) for evaluating the electrochemical behavior of the fabricated anodes. The electrochemically regulated bioanode (MWCNT/ZnS/AgNWs/PANI/Frt/GOx) obtained an open-circuit voltage of 0.55 V and produced a maximal current density of 7.6 mA cm -2 at a glucose concentration of 50 mM prepared in phosphate buffer solution (PBS) (pH 7.0) as a supporting electrolyte at a scan rate of 100 mV s -1 .

Michael Holzinger, Serge Cosnier, Paulo Henrique M. Buzzetti

Synthetic Metals • 2022

Fangyuan Zhao, Steffen Hardt, Volker Hartmann et al.

Nature Communications • 2018

Interfacing photosynthetic proteins specifically photosystem 1 (PS1) with electrodes enables light-induced charge separation processes for powering semiartificial photobiodevices with, however, limited long-term stability. Here, we present the in-depth evaluation of a PS1/Os-complex-modified redox polymer-based biocathode by means of scanning photoelectrochemical microscopy. Focalized local illumination of the bioelectrode and concomitant collection of H 2 O 2 at the closely positioned microelectrode provide evidence for the formation of partially reduced oxygen species under light conditions. Long-term evaluation of the photocathode at different O 2 concentrations as well as after incorporating catalase and superoxide dismutase reveals the particularly challenging issue of avoiding the generation of reactive species. Moreover, the evaluation of films prepared with inactivated PS1 and free chlorophyll points out additional possible pathways for the generation of oxygen radicals. To avoid degradation of PS1 during illumination and hence to enhance the long-term stability, the operation of biophotocathodes under anaerobic conditions is indispensable.

Alessandro Iannaci, Adam Myles, Thomas Flinois et al.

Bioelectrochemistry • 2020

Grafting of aryldiazonium cations bearing a p-mannoside functionality over microbial fuel cell (MFC) anode materials was performed to investigate the ability of aryl-glycoside layers to regulate colonisation by biocatalytic biofilms. Covalent attachment was achieved via spontaneous reactions and via electrochemically-assisted grafting using potential step experiments. The effect of different functionalisation protocols on MFC performance is discussed in terms of changes in wettability, roughness and electrochemical response of modified electrodes. Water contact angle measurements (WCA) show that aryl-mannoside grafting yields a significant increase in hydrophilic character. Surface roughness determinations via atomic force microscopy (AFM) suggest a more disordered glycan adlayer when electrografting is used to facilitate chemisorption. MFCs were used as living sensors to successfully test the coated electrodes: the response of the MFCs in terms of start-up time was accelerated when compared to that of MFC equipped with non-modified electrodes, this suggests a faster development of a mature biofilm community resulting from aryldiazonium modifications, as confirmed by cyclic voltammetry of MFC anodes. These results therefore indicate that modification with glycans offers a bioinspired route to accelerating biofilm colonisation without any adverse effects on final MFC outputs.

Sevinç Kurbanoğlu, Muhammad Nadeem Zafar, Federico Tasca et al.

Electroanalysis • 2018

Abstract In the present study, wild type and three mutants of pyranose 2‐oxidase (PyOx‐WT, PyOx‐MT1, PyOx‐MT2, PyOx‐MT3), which showed improved properties for D‐galactose oxidation, were investigated for their oxidising ability when immobilised on graphite electrodes. Four different flexible Os polymers with formal potentials ranging between −0.140 and 0.270 V vs. Ag|AgCl 0.1 M KCl were applied together with the various forms of PyOx to wire graphite electrodes using polyethylene glycol diglycidyl ether as crosslinking reagent. The pH profiles for the electrodes modified with wild type and all PyOx mutants in combination with the Os polymers were investigated with both glucose and galactose, respectively, since the PyOx variants showed an improved catalytic activity for galactose. All modified electrodes showed highest response in the pH range between 8.5–10 and K M , I max values for both glucose and galactose were determined. To prove the catalytic activity, the biosensors were also characterized with cyclic voltammetry. A protein amount 0.26 U was found optimum for PyOx‐WT, 0.36 U for PyOx‐MT1, 0.41 U for PyOx‐MT2 and 0.28 U for PyOx‐MT3 and the analytical characterization of the enzyme electrodes was performed for glucose and galactose under optimized conditions.