Catalytic Activity Of Glucose Oxidase Research Articles

Catalytic activity of glucose oxidase after dielectrophoretic immobilization on nanoelectrodes.

Dielectrophoresis (DEP) is an AC electrokinetic effect that is proven to be effective for the immobilization of not only cells, but also of macromolecules, e.g., antibodies and enzyme molecules. In our previous work, we have already demonstrated the high catalytic activity of immobilized horseradish peroxidase after DEP. To evaluate the suitability of the immobilization method for sensing or research in general, we want to test it for other enzymes, too. In this study, glucose oxidase (GOX) from Aspergillus niger was immobilized on TiN nanoelectrode arrays by DEP. Fluorescence microscopy showed the intrinsic fluorescence of the immobilized enzymes flavin cofactor on the electrodes. The catalytic activity of immobilized GOX was detectable, but a fraction of less than 1.3% of the maximum activity that was expected for a full monolayer of immobilized enzymes on all electrodes was stable for multiple measurement cycles. Therefore, the effect of DEP immobilization on the catalytic activity strongly depends on the used enzyme. This article is protected by copyright. All rights reserved.

Metal-organic framework (MOF) hybridized gold nanoparticles as a bifunctional nanozyme for glucose sensing.

Inspired by natural enzymes that possess multiple catalytic activities, here we develop a bifunctional metal-organic frame-work (MOF) for biosensing applications. Ultrasmall gold nano-particles (AuNPs) are grown in the internal cavities of an iron (Fe) porphyrin-based MOF to produce a hybridized nanozyme, AuNPs@PCN-224(Fe), in which AuNPs and PCN-224(Fe) exhibit the catalytic activity of glucose oxidase (GOx) and horseradish peroxidase (HRP), respectively. We established that the bifunctional nanozyme was capable of a cascade reaction to generate hydrogen peroxide in the presence of d-glucose and oxygen in situ, and subsequently activate a colorimetric or chemiluminescent substrate through HRP-mimicking catalytic activity. The nanozyme was selective over a range of other saccharides, and 93% of the catalytic activity was retained after being recycled five times.

An Enzyme-Engineered Nonporous Copper(I) Coordination Polymer Nanoplatform for Cuproptosis-Based Synergistic Cancer Therapy.

Cuproptosis, a newly identified form of regulated cell death that is copper-dependent, offers great opportunities for exploring the use of copper-based nanomaterials inducing cuproptosis for cancer treatment. Here, a glucose oxidase (GOx)-engineered nonporous copper(I) 1,2,4-triazolate ([Cu(tz)]) coordination polymer (CP) nanoplatform, denoted as GOx@[Cu(tz)], for starvation-augmented cuproptosis and photodynamic synergistic therapy is developed. Importantly, the catalytic activity of GOx is shielded in the nonporous scaffold but can be "turned on" for efficient glucose depletion only upon glutathione (GSH) stimulation in cancer cells, thereby proceeding cancer starvation therapy. The depletion of glucose and GSH sensitizes cancer cells to the GOx@[Cu(tz)]-mediated cuproptosis, producing aggregation of lipoylated mitochondrial proteins, the target of copper-induced toxicity. The increased intracellular hydrogen peroxide (H2 O2 ) levels, due to the oxidation of glucose, activates the type I photodynamic therapy (PDT) efficacy of GOx@[Cu(tz)]. The in vivo experimental results indicate that GOx@[Cu(tz)] produces negligible systemic toxicity and inhibits tumor growth by 92.4% in athymic mice bearing 5637 bladder tumors. This is thought to be the first report of a cupreous nanomaterial capable of inducing cuproptosis and cuproptosis-based synergistic therapy in bladder cancer, which should invigorate studies pursuing rational design of efficacious cancer therapy strategies based on cuproptosis.

Antineoplastic Enzyme as Drug Carrier with Activatable Catalytic Activity for Efficient Combined Therapy.

The delivery of glucose oxidase (GOx) requires extra carriers, which suffers from early leakage and exposure of GOx. These issues will be of less concern if GOx itself acts as a drug carrier. However, the catalytic activity of GOx in the blood still needs to be inhibited. Herein, we found that GOx could self-assemble with hydrophobic molecules into uniform and stable nanoparticles (NPs), including sorafenib, 4'-(amino-methyl phenyl)-2,2' : 6',2''-terpyridine modified cyanin and paclitaxel. The catalytic activity of GOx in NPs was significantly inhibited due to the binding of small molecules with its hydrophobic pockets. After dissociation in the tumor acidic microenvironment, the enzyme activity of GOx could be largely recovered. This acidity-triggered "OFF-to-ON" process ensured safe intravenous administration of GOx-based NPs. In vivo experiments showed that the combined starvation therapy and ferroptosis/photothermal therapy/chemotherapy effectively inhibited 4T1 breast tumor growth.

Antineoplastic Enzyme as Drug Carrier with Activatable Catalytic Activity for Efficient Combined Therapy

AbstractThe delivery of glucose oxidase (GOx) requires extra carriers, which suffers from early leakage and exposure of GOx. These issues will be of less concern if GOx itself acts as a drug carrier. However, the catalytic activity of GOx in the blood still needs to be inhibited. Herein, we found that GOx could self‐assemble with hydrophobic molecules into uniform and stable nanoparticles (NPs), including sorafenib, 4′‐(amino‐methyl phenyl)‐2,2′ : 6′,2′′‐terpyridine modified cyanin and paclitaxel. The catalytic activity of GOx in NPs was significantly inhibited due to the binding of small molecules with its hydrophobic pockets. After dissociation in the tumor acidic microenvironment, the enzyme activity of GOx could be largely recovered. This acidity‐triggered “OFF‐to‐ON” process ensured safe intravenous administration of GOx‐based NPs. In vivo experiments showed that the combined starvation therapy and ferroptosis/photothermal therapy/chemotherapy effectively inhibited 4T1 breast tumor growth.

A Novel Luminescent "Nanochip" as a Tandem Catalytic System for Chemiluminescent Detection of Sweat Glucose.

Accurate sweat glucose detection is a promising alternative to invasive finger-prick blood tests, allowing for self-monitoring of blood glucose with good patient compliance. In this study, we have developed a tandem catalytic system, termed as a luminescent "nanochip" (LAON), which was composed of gold nanoparticles (AuNPs) and N-(aminobutyl)-N-(ethylisoluminol) (ABEI)-engineered oxygen-doped carbon nitride (O-g-C3N4), for chemiluminescent detection of sweat glucose. The LAON exhibits dual catalytic activity of glucose oxidase and peroxidase and can not only oxidize glucose to generate H2O2 but catalyze H2O2-mediated luminol chemiluminescence, resulting in sensitive detection of glucose. We identify that the LAON can precisely detect glucose with a detection limit of 0.1 μM, enabling us to measure glucose levels in different biological samples. Particularly, the LAON is capable of sensitively and accurately monitoring dynamic changes in sweat glucose during exercise. Therefore, the LAON provides an alternative approach to supersede invasive blood tests and may improve the management of diabetes mellitus.

A novel peroxidase/oxidase mimetic Fe-porphyrin covalent organic framework enhanced the luminol chemiluminescence reaction and its application in glucose sensing.

A Fe-porphyrin covalent organic framework (Fe-PorCOF) was prepared through a postmodification strategy and characterized using different techniques. Fe-PorCOF exhibits an inherent peroxidase/oxidase mimetic catalytic activity and sharply accelerates chemiluminescence (CL) reactions between luminol and hydrogen peroxide (H2 O2 ) or dissolved oxygen (O2 ) under alkaline conditions. The catalytic role was attributed to a significant increase in production of reactive oxygen species. Using the imminent peroxidase mimetic catalytic activity of Fe-PorCOF, a new CL method was developed for determination of H2 O2 over a linear range from 0.01 to 10.0 μmol·L-1 and with a limit of detection of 5.3 nmol·L-1 . The combination of the peroxidase mimetic catalytic activity of Fe-PorCOF with the catalytic activity of glucose oxidase on glucose oxidation presents a sensitive CL method for glucose assay. The linear range and the detection limit for glucose were 0.05-8.0 μmol·L-1 and 4.0 nmol·L-1 , respectively. The practicability of this method was assessed by determination of glucose in human sera. As a peroxidase/oxidase mimetic, Fe-PorCOF is easy to prepare and exhibits good catalytic efficiency in the luminol reaction. We believe that this strategy will promote the development of a CL field with functional COFs as a catalyst.

Glucose Oxidase-Instructed Traceable Self-Oxygenation/Hyperthermia Dually Enhanced Cancer Starvation Therapy.

Cancer theranostics based on glucose oxidase (GOx)-induced starvation therapy has got more and more attention in cancer management. Herein, GOx armed manganese dioxide nanosheets (denoted as MNS-GOx) were developed as cancer nanotheranostic agent for magnetic resonance (MR)/photoacoustic (PA) dual-modal imaging guided self-oxygenation/hyperthermia dually enhanced starvation cancer therapy. The manganese dioxide nanomaterials with different morphologies (such as nanoflowers, nanosheets and nanowires) were synthesized by a biomimetic approach using melanin as a biotemplate. Afterwards, the manganese dioxide nanosheets (MNS) with two sides and large surface area were selected as the vehicle to carry and deliver GOx. The as-prepared MNS-GOx can perform the circular reaction of glucose oxidation and H2O2 decomposition for enhanced starvation therapy. Moreover, the catalytic activity of GOx could be further improved by the hyperthermia of MNS-GOx upon near-infrared laser irradiation. Most intriguingly, MNS-GOx could achieve “turn-on” MR imaging and “turn-off” PA imaging simultaneously. The theranostic capability of MNS-GOx was evaluated on A375 tumor-bearing mice with all tumor elimination. Our findings integrated molecular imaging and starvation-based synergistic cancer therapy, which provided a new platform for cancer nanotheranostics.

A universal one-pot assay strategy based on bio-inorganic cascade catalysts for different analytes by changing pH-dependent activity of enzymes on enzyme mimics

In general, peroxidase mimics show optimal activity at acidic pH, while many enzymes work at physiological pH. To realize one-pot colorimetric detection based on enzyme-nanozyme-coupled system, the usual strategy is to change the pH-dependent activity of nanozymes, which is difficult for most of nanozymes. Unlike common strategies, we changed the pH-dependent activity of enzymes rather than nanozymes. First, we facilely synthesized Co3O4 magnetic peroxidase mimics with uniform size, good dispersibility and superparamagnetism by using protein as templates at mild condition. The as-prepared Co3O4 magnetic nanoparticles (MNPs) were covered with the layers of protein, facilitating the further functionalization with enzymes. Exhilaratingly, we discovered that the immobilization on Co3O4 MNPs could regulated pH-dependent activity of enzymes, such as glucose oxidase (GOx) and glucoamylase (GA). Based on the overlapped pH range between peroxidase-like activity of Co3O4 MNPs and catalytic activity of GOx, the hybrid cascade catalysts were employed for a one-pot glucose detection, exhibiting wide detection range and good selectivity. Furthermore, GA and GOx were co-mobilized on Co3O4 MNPs to realize the one-pot colorimetric starch detection, confirming the universality of the proposed strategy. As an additional bonus, hybrid cascade catalysts could be expediently separated from the reaction solution under the magnetic field in order to rapidly terminate the reaction and recycle enzymes. This work would open an avenue for the various one-pot enzyme-nanozyme-coupled assay.

Adsorption and catalytic activity of glucose oxidase accumulated on OTCE upon the application of external potential

This article describes the adsorption of glucose oxidase (GOx) onto optically transparent carbon electrodes (OTCE) under the effect of applied potential and the analysis of the enzymatic activity of the resulting GOx/OTCE substrates. In order to avoid electrochemical interferences with the enzyme redox center, control electrochemical experiments were performed using flavin adenine dinucleotide (FAD) and GOx/OTCE substrates. Then, the enzyme adsorption experiments were carried out as a function of the potential applied (ranged from the open circuit potential to +950mV), the pH solution, the concentration of enzyme, and the ionic strength on the environment. The experimental results demonstrated that an increase in the adsorbed amount of GOx on the OTCE can be achieved when the potential was applied. Although the increase in the adsorbed amount was examined as a function of the potential, a maximum enzymatic activity was observed in the GOx/OTCE substrate achieved at +800mV. These experiments suggest that although an increase in the amount of enzyme adsorbed can be obtained by the application of an external potential to the electrode, the magnitude of such potential can produce detrimental effects in the conformation of the adsorbed protein and should be carefully considered. As such, the article describes a simple and rational approach to increase the amount of enzyme adsorbed on a surface and can be applied to improve the sensitivity of a variety of biosensors.

Oxidation of glucose to gluconic acid using a colloidal catalyst containing gold nanoparticles and glucose oxidase

A simple method for the preparation of colloidal catalysts of the aerobic oxidation of glucose, viz., metal polymeric complexes of gold or its alloy with silver, as well as complexes containing glucose oxidase, was developed. The complexes containing glucose oxidase were synthesized by the covalent immobilization of enzyme in aqueous medium (in the absence of toxic chemicals and solvents) on the shell of the alternate maleic acid copolymer covering a core made of nanogold or its alloy. The catalysts obtained were studied by transmission electron microscopy, spectrophotometry, IR spectroscopy, and light scattering. All the catalysts were active and selective in the process of the aerobic oxidation of glucose to gluconic acid (H2O2 registration method), whereas the catalytic activity of glucose oxidase was 73–96% (relative to the introduced enzyme). The highest activity was found for the colloidal catalysts containing gold and silver alloy in the core at pH 9.0 and T = 50 °C (registration of glucose and gluconic acid by 1H NMR). 1H NMR spectroscopy was used for the first time for the registration of glucose and gluconic acid in such reactions.

Enzymes as bionanoreactors: glucose oxidase for the synthesis of catalytic Au nanoparticles and Au nanoparticle-polyaniline nanocomposites.

The use of biomaterials such as enzymes for the synthesis of functional materials is important because such biologically guided processes can significantly reduce energy consumption in manufacturing processes. Glucose oxidase (GOx) has been exploited as a reducing as well as a stabilising agent for the green chemical synthesis of Au nanoparticles at pH 7.0 under ambient conditions. The synthesized Au nanoparticle-GOx composite was found to act as a highly-effective catalyst towards the reduction of p-nitrophenol to p-aminophenol in the presence of NaBH4. The catalytic activity of GOx was largely inhibited after its participation in the reduction of metal salt to form nanoparticles. A detailed mechanistic investigation was carried out using fluorescence spectroscopy, Fourier transform infra-red (FTIR) spectroscopy and circular dichroism (CD) to gain insights into the conformational changes in the enzyme structure. The catalytic activity of GOx towards the oxidation of glucose was taken advantage of to form a Au nanoparticle-polyaniline (Au NP-PANI) composite at room temperature. The production of the green emeraldine salt form of polyaniline (PANI) was extremely low in case of Au nanoparticle-GOx composite, where GOx was involved as a reducing agent. However, H2O2 generated during the catalytic reaction of GOx acted as a simultaneous reducing and oxidizing agent, leading to the formation of an Au NP-PANI core-shell composite in a controlled fashion.

Opening windows on new biology and disease mechanisms: development of real-time in vivo sensors

From X-ray radiology to blood panels, medicine is informed by the status of in vivo systems and their deviations from normal ranges. It is now widely acknowledged that the fundamental aetiology of many disease states can be understood at the molecular level. Over the past half a century there has been a push towards the development of novel technologies to probe the in vivo molecular status of biological systems for diagnosis, prognosis and response to therapies [1]. This Theme Issue will highlight some of the most recent exciting work in the fields of molecular-, nano-, and micro-scale devices for real-time in vivo sensing. Although this field is already large and growing, this Introduction will attempt to provide context and background for understanding this set of papers, and how they attempt to address the unique challenges that arise in the development of these novel and powerful devices. At the most fundamental level, a sensor is simply a device capable of quantifying or detecting a specific, biologically relevant analyte. Practically, this consists of a detector (such as an electrode, antibody, aptamer, peptide or enzyme) paired with a detection method (which may be optical, electrochemical or magnetic, among others). In this Theme Issue, we will focus on biosensors capable of interrogating the status of biological systems in vivo and at high temporal resolution. These in vivo sensors promise to have great utility in the future, as they will allow continuous, rapid monitoring of biological systems in the context of disease, response to therapy, cell–drug interactions or understanding normal biology. The first real-time in vivo sensors were electrochemical glucose detectors that took advantage of the catalytic activity of glucose oxidase to reliably and simply detect glucose levels over time [2]. These electrochemical detection modalities have since been improved upon and incorporated into devices capable of detecting numerous analytes, including xanthine and lactate [3]. Optical sensors have recently become increasingly popular owing to their high potential for multiplexing and ease of adaptation from existing in vitro assays. For high spatial resolution, these detectors require complex imaging modalities, such as two-photon confocal imaging, for reliable temporal and spatial resolution. Feasible use of such sensors in human patients will probably sacrifice spatial resolution for broad in vivo accuracy, as in embedded optical glucose sensors [4]. Positron emission tomography sensors are well established, with a growing list of increasingly validated substrates for in vivo sensing including glucose metabolism, oxygenation, neurotransmitters and proteases. Detection methods commonly used with in vitro sensors, such asthose that take advantage of surface plasmon resonance or the piezoelectric effect have not yet found wide utility with in vivo sensors. Adaptation of these techniques for in vivo sensing will surely expand the breadth of in vivo sensors in the future. Yasun et al. [5] specifically review recent advances in the field of gold nanorods with exciting potential for in vivo applications, including the development of photoacoustic imaging techniques for cancer. Although the range of in vitro biosensors is enormous, encompassing a huge variety of detection modalities with exquisite sensitivity, the range of in vivo

Gold nanoparticle and conducting polymer-polyaniline-based nanocomposites for glucose biosensor design

Two new nanocomposite structures (i) glucose oxidase (GOx) entrapped within polyaniline (PANI) layer (GOx/PANI) and (ii) GOx, gold nanoparticles (Au-NPs) entrapped within PANI layer (GOx/Au-NPs/PANI) were developed. These structures were deposited on the surface of carbon rod electrodes and evaluated amperometrically. It was found that in all cases Au-NPs facilitated electron transfer (ET) and they showed a positive effect on the amperometric signals of all evaluated types of electrodes. The sensitivity, apparent Michaelis constants and some other characteristics of developed biosensors were determined and evaluated. Results illustrate that GOx/PANI and GOx/Au-NPs/PANI nanocomposites retain catalytic activity of glucose oxidase and seem to be suitable for the design of amperometric biosensors. In addition we predict possible application of such nanocomposites for some other nanotechnological purposes including biomedical ones.

Evaluation of amperometric glucose biosensors based on glucose oxidase encapsulated within enzymatically synthesized polyaniline and polypyrrole

In this article potential and suitability of enzymatically synthesized conducting polymers polyaniline (PANI) and polypyrrole (PPY) for fabrication of enzymatic amperometric glucose biosensors were evaluated. The polymerisation of these polymers was induced by catalytic activity of glucose oxidase (GOx) from Penicillium vitale cross-linked by glutaraldehyde (GA) on the graphite rod electrode (GOx-electrode) surface. The main precursors for initiation of polymerisation reactions were hydrogen peroxide as an initiator of polymerisation reaction and β- d-gluconic acid as a medium, which reduced the pH towards acidic one is the most suitable for the formation of PANI and PPY. During the polymerisation reactions the immobilized GOx was self-encapsulated within formed PANI or PPY layers in order to form GOx/PANI- and GOx/PPY-modified electrodes (GOx/PANI-electrode and GOx/PPY-electrode, respectively). Kinetic properties of GOx, which is acting as a biocatalyst in GOx/PANI- and GOx/PPY-electrodes, were studied and results were compared with GOx-electrode. The results show that in both GOx/PANI- and GOx/PPY-electrodes self-encapsulated GOx exhibited different parameters of catalysed reaction kinetics due to increasing diffusion limitations if compared with that of the GOx-electrode and it allowed the detection of glucose in a wider concentration interval. Moreover, both GOx/PANI- and GOx/PPY-electrodes exhibited good operational stability and reproducibility of analytical signal. The electrochemical characteristics of formed PANI and PPY in the GOx/PANI- and GOx/PPY-electrodes were also determined. In addition, the influence of temperature, pH and common interfering compounds on the steady-state current response of modified electrodes were investigated and discussed.

聚硫堇/过氧化氢光致电化学敏感界面的构建及其对葡萄糖氧化酶催化活性的测定

A new photoelectrochemical sensing platform for H2O2 was fabricated by electropolymerization of thionine on ITO electrode. This photosensitive interface was employed as an electron acceptor, and H2O2 proceed from enzymatic catalysis was employed as an electron donor, developing a new determination method for catalytic activity of protein. In the paper, the photoelectrochemical response of poly(thionine) immobilized on ITO electrode to H2O2 was described. The effects of bias voltage, pH of electrolyte and concentration of substrate to the photoelectrochemical response were investigated. The feasibility of method was acknowledged through monitoring the catalytic activity of glucose oxidase. The present method is an economical, speedy, simple and convenient technique to detect the catalytic activity of protein without hydrogen peroxidase.

Hemin/G-quadruplexes as DNAzymes for the fluorescent detection of DNA, aptamer–thrombin complexes, and probing the activity of glucose oxidase

Hemin/G-quadruplex catalyzes the H(2)O(2)-mediated oxidation of Amplex Red to the fluorescent product resorufin. This process is implemented to develop hairpin nucleic acid structures for the detection of DNA, to probe the catalytic activity of glucose oxidase, to use the thrombin-aptamer complex as a catalytic readout structure, and to quantitatively analyze telomere chain composition.

New Insights into the Effects of Thermal Treatment on the Catalytic Activity and Conformational Structure of Glucose Oxidase Studied by Electrochemistry, IR Spectroscopy, and Theoretical Calculation

Protein conformational changes may be associated with particular properties such as its function, transportation, assembly, tendency to aggregate, and potential cytotoxicity. In this study, the mechanism of the effects of thermal unfolding of proteins on their catalytic activities and conformational structures were studied by utilizing glucose oxidase (GOx) as a model protein. The characteristic kinetic constants for the enzymatic reaction were evaluated by the use of an electrochemical approach under a substrate-saturated condition. A combination of quantitative second-derivative infrared analysis, two-dimensional infrared correlation spectroscopy (2D IR), and theoretical calculation was used to elucidate the conformational structures that were responsible for inactivation and denaturation of GOx induced by heat. The IR analysis demonstrated that the conformational structures of GOx, especially the α-helix and unordered structures, were greatly dependent on the system temperature. Thermal treatment resulted in the increase of the unordered structure accompanied by the loss of the α-helical structure in GOx conformation. Molecular dynamics (MD) simulations and density functional theory (DFT) calculations revealed that thermal treatment could significantly alter the electronic characteristics and the intramolecular electron transfer ability of FAD (flavin adenine dinucleotide), and hydrogen bond networks formed between FAD and the amino acid residues around the cofactor, leading to the change of the secondary structure and the catalytic activity of GOx. The study essentially paves an effective approach to investigation of the mechanism of protein unfolding.

Effect of silica nanoparticles with different sizes on the catalytic activity of glucose oxidase

In this work we present a strategy for the covalent immobilization of periodate oxidized glucose oxidase (IO(4)(-) - GOx) to aminated silica nanoparticles (ASNPs) modified on gold electrodes. Silica nanoparticles greatly enhanced the catalytic ability of GOx toward the oxidation of glucose and improved the electron transfer between the GOx and the electrode surface. ASNPs of varying size--that is 100, 80, 60, and 30 nm--were prepared, and they were used to fabricate biosensors. Electrochemical impedance spectroscopy (EIS) of ferrocyanide followed the assembly process and verified the successful immobilization of IO(4)(-) - GOx on ASNPs modified on gold electrodes. From the analysis of catalytic signals of biosensors using different sizes of ASNPs under the same conditions, the surface concentration of electrically wired enzyme (Gamma (ET)) was estimated and was found to increase with decreasing ASNPs size. Therefore, the sensitivity of biosensors using smaller ASNPs was higher than that using larger particles. Specifically, we utilized the ASNPs with optimal size (30 nm) to fabricate the glucose biosensor. The resulting electrodes showed a wide linear response to glucose at least to 6 mM and reached 95% of the steady-state current in less than 4 s with a sensitivity of 5.02 microA mM(-1) cm(-2) and a detection limit of 0.01 mM. The biosensor also showed excellent stability and good reproducibility.

Control of catalytic activity of glucose oxidase in layer-by-layer films of chitosan and glucose oxidase

The suitability of the layer-by-layer (LbL) technique, based on the alternate adsorption of oppositely charged materials, for immobilization of biomolecules has been well established. Achieving optimized results depends on the experimental conditions for film fabrication, and in most cases on the film architecture. In this paper we exploit the high catalytic activity of glucose oxidase (GOD) immobilized in LbL films with chitosan in oxidation reactions of glucose to gluconic acid. In addition to confirming previous works that these LbL films can be used in biosensors, we used the films in the reduction of a gold salt to yield metallic gold nanoparticles. The reaction kinetics was monitored by measuring the plasmon resonance band of gold nanoparticles, where the enzyme catalytic activity was found to be 92% of the activity in a homogeneous environment. This high degree of activity preservation for immobilized GOD is promising for various systems involving catalysis by GOD.