Biofuel Cells Research Articles

Development of Malate Biosensor-Containing Hydrogels and Living Cell-Based Sensors.

Malate is a key intermediate in the citric acid cycle, an enzymatic cascade that is central to cellular energy metabolism and that has been applied to make biofuel cells. To enable real-time sensing of malate levels, we have engineered a genetically encoded, protein-based fluorescent biosensor called Malon specifically responsive to malate by performing structure-based mutagenesis of the Cache-binding domain of the Citron GFP-based biosensor. Malon demonstrates high specificity and fluorescence activation in response to malate, and has been applied to monitor enzymatic reactions in vitro. Furthermore, we successfully incorporated Malon into redox polymer hydrogels and bacterial cells, enabling analysis of malate levels in these materials and living systems. These results show the potential for fluorescent biosensors in enzymatic cascade monitoring within biomaterials and present Malon as a novel tool for bioelectronic devices.

Expanding the Genetic Code of Bioelectrocatalysis and Biomaterials.

Genetic code expansion is a promising genetic engineering technology that incorporates noncanonical amino acids into proteins alongside the natural set of 20 amino acids. This enables the precise encoding of non-natural chemical groups in proteins. This review focuses on the applications of genetic code expansion in bioelectrocatalysis and biomaterials. In bioelectrocatalysis, this technique enhances the efficiency and selectivity of bioelectrocatalysts for use in sensors, biofuel cells, and enzymatic electrodes. In biomaterials, incorporating non-natural chemical groups into protein-based polymers facilitates the modification, fine-tuning, or the engineering of new biomaterial properties. The review provides an overview of relevant technologies, discusses applications, and highlights achievements, challenges, and prospects in these fields.

Implementation of a simple functionalisation of graphene (Gii-Sens) in the determination of a suitable linker for use in biocatalytic devices

We adapted a single-step method to functionalise three-dimensional graphene foam (Gii-Sens) electrodes with a 1-pyrenebutyric acid N-hydroxysuccinimide ester (Pyr-NHS). The physical and chemical properties of these functionalised electrodes were subsequently probed via Raman spectroscopy, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy. Combined with data acquired from cyclic voltammetry and electrical impedance spectroscopy, we confirmed the presence of Pyr-NHS on the surface of the graphene foam in sufficient quantity for it to serve as a suitable linker for the immobilisation of the enzyme glucose dehydrogenase (GDH) on the electrode. Evidence of this immobilisation was provided through electrochemical characterisation, before demonstrating an active enzyme response from GDH via the mediated oxidation of glucose at the electrode surface. A proportional relationship between the concentration of glucose and the peak anodic current from the redox mediator p-aminophenol led to the determination of a high sensitivity of 22.7µA/mM/cm2 and a limit of detection of 5.25 µM. Such a result confirms the viability of these functionalised graphene foam electrodes as a metal-free high-performing anode within miniaturised, glucose-based biocatalytic devices, including enzymatic biofuel cells and biosensors.

Dual-functional carbon nanotube yarn supercapacitor for real-time reactive oxygen species monitoring and sustainable energy supply in implantable device

Smart stents integrate embedded sensors and advanced technology, providing a real-time diagnostic feedback, particularly for detection of thrombotic events. A continuous monitoring reactive oxygen species (ROS) in blood vessels is crucial for cardiovascular disease. The provision of a continuous power supply to sensors integrated within blood vessels is challenging. This study introduces a novel device that combines a sensor and supercapacitor, functioning as a ROS sensor and enabling continuous charging and discharging within blood vessels. This device uses yarn-shaped electrodes integrated with cytochrome c and carbon nanotubes (Cyt.c/CNT). The Cyt.c/CNT electrode exhibits a high specificity to ROS with an sensitivity (49.02 μA μM−1 cm−2), as a real-time biosensor for monitoring of cellular ROS levels in living cells. In addition, it exhibited an energy storage performance of 257.95 mF cm−2 as a supercapacitor and maintained a stable performance during 10,000 repeated cycles in various biofluids. Notably, the integration of the Cyt.c/CNT electrode with an enzymatic biofuel cell enables continuous charging and discharging in a biofluid, making it a promising system for in-vivo applications. This study presents the potential of Cyt.c for ROS sensing as well as its potential as an energy storage system, showing new possibilities for implantable devices for cardiovascular diseases.

Advanced design of target-driven self-powered sensor assisted by cascade catalytic strategy

In this work, a self-powered microsensor platform based on enzyme biofuel cells (EBFCs) was developed for intelligent monitoring of disease markers miRNA-451. The cascade catalysis system constructed by using the strategy of enzyme-like ZIF-8 nanocapsule incorporation with biological enzymes, which could simultaneously take into account the specificity of biological enzymes and the high activity of nano-enzymes, significantly promoted the electron transfer between glucose and the bio-anode surface, and improved the sensitivity and stability of the sensing system. Meanwhile, the target-triggered hybridisation chain reaction (HCR) amplification strategy to achieve exponential signal amplification based on accurate recognition, and jointly improve the detection sensitivity. As expected, the micro-sensor platform has a wide linear range of 0.5-1.0 fmol/L with a low limit of detection (LOD) of 0.13 fmol/L (S/N=3) and exhibits excellent selectivity, reproducibility and stability in interference assays under optimal detection conditions. The designed self-powered system is simple to construct, easy to transport and the data transmission mode is intelligent and controllable, which is expected to be used in basic biochemical research, clinical diagnosis and environmental monitoring.

A Self-Powered Enzymatic Glucose Sensor Utilizing Bimetallic Nanoparticle Composites Modified Pencil Graphite Electrodes as Cathode.

Enzymatic biofuel cells (EBFC) are promising sources of green energy owing to the benefits of using renewable biofuels, eco-friendly biocatalysts, and moderate operating conditions. In this study, a simple and effective EBFC was presented using an enzymatic composite material-based anode and a nonenzymatic bimetallic nanoparticle-based cathode respectively. The anode was constructed from a glassy carbon electrode (GCE) modified with a multi-walled carbon nanotube (MWCNT) and ferrocene (Fc) as a conductive layer coupled with the enzyme glucose oxidase (GOx) as a sensitive detection layer for glucose. A chitosan layer was also applied to the electrode as a protective layer to complete the composite anode. Chronoamperometry (CA) results show that the MWCNT-Fc-GOx/GCE electrode has a linear relationship between current and glucose concentration, which varied from 1 to 10mM. The LOD and LOQ were calculated for anode as 0.26mM and 0.87mM glucose, respectively. Also the sensitivity of the proposed sensor was calculated as 25.71 A/mM. Moreover, the studies of some potential interferants show that there is no significant interference for anode in the determination of glucose except ascorbic acid (AA), uric acid (UA), and dopamine (DA). On the other hand, the cathode consisted of a disposable pencil graphite electrode (PGE) modified with platinum-palladium bimetallic nanoparticles (Nps) which exhibit excellent conductivity and electron transfer rate for the oxygen reduction reaction (ORR). The constructed EBFC was optimized and characterized using various electroanalytical techniques. The EBFC consisting of MWCNT-Fc-GOx/GCE anode and Pt-PdNps/PGE cathode exhibits an open circuit potential of 285.0mV and a maximum power density of 32.25µWcm-2 under optimized conditions. The results show that the proposed EBFC consisting of an enzymatic composite-based anode and bimetallic nanozyme-based cathode is a unique design and a promising candidate for detecting glucose while harvesting power from glucose-containing natural or artificial fluids.

Cooperative Control of Bioelectrocatalytic Activity for Thermo- and Photo-Switchable Cup-Stacked Carbon Nanofiber Electrodes Modified with Phase Transition Polymer and Heme Peptide.

Empowering biocatalyst-modified electrodes with the ability to both enforce and perceive will enable the development of intrinsically switchable bioelectrode systems, which exhibit autonomous and heteronomous actions specific to living organisms. However, the electrocatalytic activity of switchable bioelectrodes reported so far has been controlled by changes in the rate of substrate transport to biocatalysts. Here, we prepared a cup-stacked carbon nanofiber (CSCNF) electrode modified with a thermoresponsive N-isopropylacrylamide-based polymer containing peroxidase model compounds (HP). As CSCNFs worked as a converter from near-infrared (NIR) light to heat, bioelectrocatalytic activity of the electrode to H2O2 reduction was reversibly controlled by changes in the amount of electroactive HP, based on expanded and contracted states of the polymers induced by not only environmental temperature changes but also external NIR light irradiation. This intrinsically switchable bioelectrode technique would hold promise for adding new performances in electrochemical biosensors and biofuel cells, for example, autonomous and heteronomous tunable sensitivity and capacity.

A high-power hybrid carbon nanotube/three-dimensional reduced graphene oxide glucose/O2 enzymatic biofuel cell

Long-lasting, high-performance enzymatic biofuel cells (EBFCs) are among the most promising candidates for renewable and green power generation. There are two main drawbacks to EBFCs: 1) short enzyme lifetime due to the enzyme's (protein) denaturation; and 2) low electron transfer efficiency as the enzyme's active site is deeply buried inside the non-conductive protein structure of the enzyme. In this study, a hybrid of carbon nanotubes (CNT) and three-dimensional graphene (3DG) was used to immobilize the glucose oxidase (GOx) on the surface of a glassy carbon electrode (GCE) to fabricate a modified bioanode in a glucose/O2 EBFC. This facile and low-cost CNT/3DG hybrid is a solution to the problems of instability, short lifespan, and poor electron transport in EBFCs. The exceptional electrocatalytic activity of the porous CNT/3DG hybrid is demonstrated by its effective immobilization of GOx and ability to collect energy from glucose oxidation by direct electron transfer (DET) while preserving the structure of the enzyme. The CNT acts like a tiny electrical wire that reaches and harvests the electron directly from the flavin adenine dinucleotide (FAD) (the redox center of GOx) and transfers it to the electrode surface, thus enhancing the performance of the EBFC. The immobilized GOx lifetime was increased to 210 days with a maximum power density of 253.36 µWcm-2 at 0.65 V. These results demonstrate the attractive capability of the CNT/3DG hybrid in the development of efficient biofuel cells and biosensors that employ enzymes in their structures.

Signal amplification strategy based on target-controlled release of mediator for ultrasensitive self-powered biosensing of acetamiprid

Self-powered biosensors with high sensitivity have garnered significant interest for their potential applications in the realm of portable sensing. Herein, a self-powered biosensor with a novel signal amplification strategy was developed by integrating target-controlled release of mediator with an enzyme biofuel cell for the ultrasensitive detection of acetamiprid (ACE). Zeolitic imidazolate framework-67 was utilized as both a nanocontainer for capturing the electron mediator 2,2′-azidobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and a precursor for the synthesis of cobalt nanoparticles/nitrogen, sulfur-codoped carbon nanotubes (Co NPs/NS-CNTs), which were employed as the electrode material for constructing both the glucose oxidase-based bioanode and the laccase-based biocathode. The target analyte ACE can specifically bind to its aptamer, leading to the release of ABTS, which cyclically participates in the catalytic reaction of the biocathode, thereby amplifying the electrochemical signal. By leveraging the benefits of ABTS cyclic catalysis and the effective electrocatalysis of bioelectrodes based on Co NPs/NS-CNTs, the self-powered biosensor has a broad detection range of 0.1–1000 fM and a low detection limit of 25 aM toward ACE. The proposed signal amplification approach presents a promising strategy for enhancing sensitivity and enabling portable analysis in applications of food safety, environmental monitoring, and medical diagnostics.

Alcohol Oxidase Linked Enzyme Cascade as Anodic Biofuel Cell Catalyst

Alcohol Oxidase Linked Enzyme Cascade as Anodic Biofuel Cell Catalyst

Hydrogel‐Based Functional Materials for Thermoelectric Applications: Progress and Perspectives

AbstractHydrogels are renowned for their complex structures and unique physicochemical properties, establishing them as key materials in bioenergy harvesting applications. They are used in various applications, including triboelectric nanogenerators, piezoelectric, hydraulic, thermoelectric, and biofuel cells. Among these, hydrogels as key materials for thermoelectric applications represent a technology capable of continuously converting biological energy (thermal energy) into electrical energy. This technology shows great potential and commercial value in body monitoring, energy storage, and human‐machine interaction applications. Given its rapid development, a timely review focusing on the research progress of hydrogels and their composites in thermoelectric technology is presented. This review discusses various types of hydrogels used for thermoelectric power generation and refrigeration, their unique properties, strategies for enhancing their thermoelectric performance, and their applications in the field. Finally, the remaining challenges and feasible strategies are identified for improving the efficiency, stability, application range, and system‐level integration of next‐generation hydrogels for thermoelectric applications.

Layer-by-layer Fabrication of Gold Nanoparticles/Polyaniline Modified Gold Electrodes for Direct Non-enzymatic Oxidation of Glucose

Background: Non-enzymatic direct glucose biofuel cell is a promising technology to harness sustainable renewable energy. Furthermore, monitoring glucose levels is essential for human lives with age. Thus, there is an increasing need to develop highly efficient and stable modified electrodes. Methods: This study reported the manufacture of gold nanoparticles/polyaniline/modified gold electrodes (Au NPs/PANI/Au electrode) based on the electrochemical polymerization method followed by the deposition of gold nanoparticles. The shapes and chemical constitution of the electrodes were examined by using different techniques including SEM, FTIR, XRD, EDS, and Raman spectroscopy techniques. The electrocatalytic efficiency of the present electrodes toward direct glucose oxidation was evaluated by applying cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry techniques. Results: The results exhibited high electrocatalytic performance for direct glucose electrooxidation in alkaline media. The modified electrodes show the ability to electrooxidation of various glucose concentrations (1 μM ̶ 100 μM) with a limit of detection and limit of quantitation of 140 nM and 424 nM, respectively. Furthermore, the Au NPs/PANI/Au electrode showed higher durability, sensitivity, and selectivity toward glucose oxidation than the Au NPs/ Au electrode, which confirmed the role of the PANI layer in enhancing the stability of the modified electrode. Conclusion: Moreover, the molar fraction of glucose to KOH has a crucial role in the output current. Hence, the modified electrodes are great candidates for direct glucose biofuel cell application.

Improving the performance of glucose oxidase biofuel cell by methyl red and chitosan composite electrodes

This research aims to improve the output power of self-pumping glucose enzymatic biofuel cell (EBFC) and modifying the anode. Adding a fixed ratio of methyl red-chitosan (MR-CS) can effectively improve the EBFC efficiency and stability. In addition, chitosan can be obtained from discarded crustacean fishery waste objects such as shrimp and oysters, are also significant to the use of environmentally friendly materials. The catalyst was immobilized on pyrenecarboxaldehyde (PCA), polyethyleneimine (PEI) and multi-wall carbon nanotubes (MWCNT) and combined with glucose oxidase (GOx). Finally, the [PCA/GOx]/PEI/Nafion solution/MWCNT/[MR-CS] catalyst was immobilized on the carbon cloth. Experimental analysis was progressed under the preparation of enzyme-supported electrode to observe the feasibility of the anode electrode. Experiment including Fourier transform infrared spectroscopy (FTIR) to analyze the distribution of functional groups after modification of the carbon cloth electrode, and through the comparison of the ultraviolet–visible spectrometer (UV–Vis), it can be known that the concentration ratio of [MR-CS] is 1:5, the glucose oxidase load can be maximized. Electrochemical analysis (Cyclic Voltammetry, CV) measures the activity of the maximum reaction of the anode material and the corresponding redox peak, and scanning electron microscope (SEM) observes the surface morphology of the modified electrode. Self-pumping glucose enzymatic biofuel cell module was assembled and examined, the results showed that the maximum output power density (MPD) was 2.64 mW/cm2.

Featuring the stagnation point flow of Casson nanofluid with thermal radiation and swimming microorganisms over a stretching sheet: A computational modeling via analytical method

Here, the investigation examines the flow of a nanomaterial toward stagnation point past stretching sheet having microorganism. The thermal radiative and heat generation have been accounted as well as convective boundary conditions. The influence of thermophoretic and Brownian movment has been considered. It has been proposed that the suitable transformation be utilized in order to convert the system of PDEs into ODEs. The analytical solutions are created through the Homotopy Analysis Method (HAM). The physical parameters with modelled equations have been graphically explained with related physical results. The numeric magnitude of drag friction, heat, mass transport and motile microorganism dendity were also computed and described for numerous emerging parameters. The result shows that the flow decreases with the rinsing value of Casson parameter. The impact of enhancing fluid parameters is too depressed the momentum and thermal boundary layer. The augment in the radiation boost the thermal layer whereas an enlargement in the input of the Lb tends to depreciation the motile density. Validation of the work is existed by validating the current outcomes with previous publishing results. The existing and potential applications of bioconvection have generated a new fascination in the theoretical investigation of the synthesis and process control in biofuel cells and bioreactors.

Bioinspired design of rhodium single-atom nanozymes enable a non-poisoning pathway for direct formic acid oxidation in enzymatic biofuel cells

Solving the dilemma of CO poisoning in electrocatalysts is the crucial step in the commercialization of direct formic acid fuel cells, however, it remains a challenge to design catalysts with high reaction tendency for the direct formic acid oxidation reaction (FAOR) as elaborately as natural enzymes. Herein, inspired by formate oxidase (FOD) with a delicate catalytic pocket, we report that rhodium single-atom nanozymes (Rh SAzymes) can catalyze direct FAOR without worrying about CO poisoning. Impressively, Rh SAzymes exhibit non-CO pathway for direct FAOR in both enzyme-like biocatalytic and electrocatalytic conditions. By combining docking studies and density functional theory calculations, we reveal that this striking reaction tendency mainly stems from thermodynamically unfavorable pathway in the generation and adsorption of CO, much more like that of natural FOD. Moreover, we successfully construct the membrane-less FA/O2 enzymatic biofuel with an open-circuit potential (OCP) of 0.68±0.01 V and a maximum power density (Pmax) of 0.41±0.01 mW cm−2. With 100 % selectivity toward direct anti-poisoning pathway and flexible configuration, the device realizes long-term stable operation and miniaturized goals. Our work not only provides a methodological template for exploring the CO-resilient reaction mechanism of enzyme-like biocatalysts as well as their homologous electrocatalysts in canonical reactions of fuel cells but also paves avenues for the integration of nanozymes in energy equipment.

Effects of Cross-linker Chemistry on Bioelectrocatalytic Reactions in a Redox Cross-linked Network of Glucose Dehydrogenase and Thionine.

Enzyme-mediator bioconjugation is emerging as a building block for designing electrode platforms for the construction of biosensors and biofuel cells. Here, we report a one-pot bioconjugation technique for flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) and thionine (TH) using a series of cross-linkers, including epoxy, N-hydroxysuccinimide (NHS), and aldehydes. In this technique, FAD-GDH and thionine are conjugated through an amine cross-linking reaction to generate a redox network, which has been successfully employed for the oxidation of glucose. The bioconjugation chemistry of cross-linkers with the amino groups on FAD-GDH and thionine plays a vital role in generating distinct network structures. The epoxy-type cross-linker reacts with the primary and secondary amines of thionine at room temperature, thereby producing an FAD-GDH-TH-FAD-GDH hyperbranched bioconjugate network, the aldehyde undergoes a rapid cross-linking reaction to produce a network of FAD-GDH-FAD-GDH, while the NHS-based cross-linker can react with the primary amines of both FAD-GDH and thionine, forming an FAD-GDH-cross-linker-TH polymeric network. This reaction has the potential to enable the conjugation of a redox mediator with a FAD-GDH network, which is particularly essential when designing an enzyme electrode platform. The data demonstrated that the polymeric cross-linked network based on the NHS cross-linker exhibited a considerable increase in electron transport while producing a catalytic current of 830 μA cm-2. The cross-linker spacer arm length also affects the overall electrochemical function of the network and its performance; an adequate spacer length containing a cross-linker is required, resulting in a faster electron transfer. Finally, a leaching test confirmed that the stability of the enzyme electrode was improved when the electrode was tested using the redox probe. This study elucidates the relationship between cross-linking chemistry and redox network structure and enhances the high performance of enzyme electrode platforms for the oxidation of glucose.

Textile-Based Membraneless Microfluidic Double-Inlet Hybrid Microbial-Enzymatic Biofuel Cell.

This study reports the development of a textile-based colaminar flow hybrid microbial-enzymatic biofuel cell. Shewanella MR-1 was used as a biocatalyst on the anode, and bienzymatic system catalysts based on glucose oxidase and horseradish peroxidase were applied on an air-breathing cathode to address the overpotential loss in a body-friendly way. A single-layer Y-shaped channel configuration with a double-inlet was adopted. Microchannels of biofuel cells were patterned by silk screen printing with Ecoflex to maintain the flexibility of textile substrates without harm to the human body. The electrodes were fabricated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and a mixture of multiwalled carbon nanotubes and single-walled carbon nanotubes by screen printing. The effects of electrode materials, catalyst type, catalyst concentration, and glucose concentration in the catholyte were investigated to optimize the fuel cell performance. The peak power density (44.9 μW cm-2) and maximum current density (388.9 μA cm-2) of the optimized hybrid biofuel cell were better than those of previously reported textile- or paper-substrate microscale single microbial fuel cells. The developed biofuel cell will be a useful platform as a microscale power source that is harmless to the environment and living organisms.

Novel self-powered sandwich type Aptamer sensor for estrogen detection assisted with peroxidase mimic Cu-MOF

A novel self-powered and flexible enzymatic biofuel cell (EBFC)-based aptasensor was developed for the sensitive and selective detection of 17 β-estradiol (E2). A flexible polyvinyl alcohol (PVA)-tannic acid‑carbon nanotube/reduced graphene oxide (PTCR) substrate was modified with gold nanoparticles (AuNPs) and thiolated aptamer 1 (Apt1) to yield Apt1@AuNPs/PTCR. A copper-based metal-organic framework (Cu-MOF) with peroxidase mimicking activity was employed to anchor glucose oxidase (GOD) and Apt2, forming the Cu-MOF@GOD/Apt2 tag. When E2 was recognized by Apt1, the anchored E2 quantitatively recognized Cu-MOF@GOD/Apt2 to create a Cu-MOF@GOD/Apt2-E2-Apt1 sandwich structure for glucose oxidation to generate electrical power. Increased E2 concentrations enhanced Cu-MOF@GOD/Apt2 capture and amplified the electrical signal. The electrical power increased linearly as the E2 concentration increased from 1.0 pM to 1.0 nM. The sensor was successfully applied to various food samples and blood serum detection. This work promoted the application of novel self-powered biosensors for food safety analysis.

Significance of variable thermal conductivity and suction/injection in unsteady MHD mixed convection flow of Casson Williamson nanofluid through heat and mass transport with gyrotactic microorganisms

AbstractThe present paper explores a two‐dimensional mixed bio‐convective unsteady viscous hydro‐magnetic Casson Williamson nanofluid flow model with heat and mass transport incorporating motile microorganisms towards a stretchy spinning disc. The flow concept is accomplished by rotating a stretched disc with a time‐varying angular velocity. By applying a magnetic field normal to the axial direction, a magnetic interaction is taken into consideration. The Casson Williamson nanofluid contains nanosized particles suspended with swimming motile microorganisms and the rotation of the disc is exhibited by buoyancy forces, thermophoresis, suction/injection, zero mass flux conditions, variable thermal conductivity, Joule heating and so forth. The obtained flow narrating differential equations of the model are transformed into ordinary differential system. This is accomplished by simulating boundary value problems using the shooting technique using the ‘ND‐Solve’ approach included in the Mathematica software (Mathematica 12). The implications of the engaged parameters such as Williamson fluid parameter, Casson fluid (CF) parameter, thermophoresis parameter, Brownian motion parameter and so forth, on both axial and radial velocities, temperature, concentration of nanoparticles and microorganisms are explained by means of graphical and tabular constructions. This paper's validity has been confirmed and its findings align with those of other previously published papers. Furthermore, it is found that both the axial and radial velocity profiles are seen to be diminishing functions of the CF parameter. The identified observation may have theoretical implications for a number of engineering procedures, solar energy systems, biofuel cells and extrusion system improvement. Moreover, this work finds application in micro‐fabrication techniques and the chemical industry.

Biofuel cell-based self-powered immunosensor for detection of 17β-estradiol by integrating the target-induced biofuel release and biogate immunoassay.

A novel biofuel cell (BFC)-based self-powered electrochemical immunosensing platform was developed by integrating the target-induced biofuel release and biogate immunoassay for ultrasensitive 17β-estradiol (E2) detection. The carbon nanocages/gold nanoparticle composite was employed in the BFCs device as the electrode material, through which bilirubin oxidase and glucose oxidase were wired to form the biocathode and bioanode, respectively. Positively charged mesoporous silica nanoparticles (PMSN) were encapsulated with glucose molecules as biofuel and subsequently coated by the negatively charged AuNPs-labelled anti-E2 antibody (AuNPs-Ab) serving as a biogate. The biogate could be opened efficiently and the trapped glucose released once the target E2 was recognized and captured by AuNPs-Ab due to the decreased adhesion between the antigen-antibody complex and PMSN. Then, glucose oxidase oxidized the glucose to produce a large number of electrons, resulting in significantly increased open-circuit voltage (EOCV). Promisingly, the proposed BFC-based self-powered immunosensor demonstrated exceptional sensitivity for the detection of E2 in the concentration range from 1.0pgmL-1 to 10.0ngmL -1, with a detection limit of 0.32pgmL-1 (S/N = 3). Furthermore, the prepared BFC-based self-powered homogeneous immunosensor showed significant potential for implementation as a viable prototype for a mobile and an on-site bioassay system in food and environmental safety applications.