电聚高分子膜固定化酶生物传感器及其进展

本文将电化学聚合高分子膜固定膜酶制备的生物传感器分为以下三种主要类型，并分别 就其发展概况和发展方向进行了评述。即：以溶解氧为电子受体的的生物传感器（第一代电流型生物传感器）；以非氧介全为电子受体的生物传感器（第二代电流型生物传感器）和电子在酶和聚合高分膜之间直接进行转移的传感器（第三代电流型生物传感器）。     

Applications of Amperometric Silica Sol-Gel Modified Enzyme Biosensors

ABSTRACT

The applications of amperometric sol-gel modified enzyme biosensors in numerous analyses of clinical, industrial and environmental importance have been demonstrated. Certain biosensors have been employed as the sensor in a FIA amperometric detector. The results obtained by the biosensors generally corroborate well with the classical or official method. In many cases, the recovery results obtained by the biosensor have been satisfactory.     

The application of boron-doped diamond electrodes in amperometric biosensors

Boron-doped diamond (BDD) electrodes outperform conventional electrodes in terms of high stability, chemical inertness, wide potential window and low background current. Combining the superior properties of BDD electrodes with the merits of biosensors, such as specificity, sensitivity, and fast response, amperometric biosensors based on BDD electrodes have attracted the interests of many researchers. In this review, the latest advances of BDD electrodes with different surfaces including hydrogen-terminated, oxygen-terminated, metal nanoparticles-modified, amine-terminated, and carboxyl-terminated thin films, and microelectrodes, for the construction of various biosensors or the direct detection of biomolecules were demonstrated. The future trends of BDD electrodes in biosensing were also discussed.     

Simulations of Redox Mediation within Bioactive Hydrogels of Amperometric Biosensors

Highly hydrated bioactive hydrogels containing immobilized oxidoreductase enzymes and immobilized redox mediators were simulated as the biorecognition layer of amperometric biosensors. The linear dynamic range of the amperometric response of mediated biosensors increases and moves to higher concentration brackets with an increase in the concentration of mediator. This informs the design of biosensors that target the same analyte but possesses several independently addressable electrodes modified with hydrogels that contain different concentrations of mediator. Increases in enzyme concentration increase the linear dynamic range but does not alter the sensitivity of amperometric biosensors. Both sensitivity and linear dynamic range of mediated amperometric enzyme biosensors may be “tuned” by varying the concentrations of the enzyme and the mediator. Simulations effectively guide the initial domains of study of complex systems such as implantable biosensors.     

Electron-transfer mechanisms in amperometric biosensors

The function of amperometric biosensors is related to electron-transfer processes between the active site of an (immobilized) enzyme and an electrode surface which is poised to an appropriate working potential. Problems and specific features of architectures for amperometric biosensors using different electron-transfer pathways such as mediated electron transfer, electron-hopping in redox polymers, electron transfer using mediator-modified enzymes and carbon-paste electrodes, direct electron transfer by means of self-assembled monolayers or via conducting-polymer chains are discussed.     

基于担载贵金属纳米粒子聚苯二胺的生物传感器

系统论述了基于聚苯二胺的电流型生物传感器,如过氧化氢传感器、葡萄糖传感器和免疫传感器等的探测性能。指出聚苯二胺中的大量氨基/亚胺基及其膜的形态结构有助于加大贵金属纳米粒子的载入量,这种载有贵金属的聚苯二胺对酶的高效锚定作用以及贵金属纳米粒子的快速电子传输能力使其具有明显的电流增敏效果。聚苯二胺膜具有优异的选择透过性能,对抗坏血酸、脲酸、醋氨酚等常见干扰物质具有较强的抗干扰能力。由此制备的生物传感器生物物质探测与分析等领域展现出了广阔的应用前景。     

A Review of Glucose Biosensors Based on Graphene/Metal Oxide Nanomaterials

In recent years, considerable attention has been paid to developing economical yet rapid glucose sensors using graphene and its composites. Recently, the excellent properties of graphene and metal oxide nanoparticles have been combined to provide a new approach for highly sensitive glucose sensors. This review focuses on the development of graphene functionalized with different nanostructured metal oxides (such as copper oxide, zinc oxide, nickel oxide, titanium dioxide, iron oxide, cobalt oxide, and manganese dioxide) for use as glucose biosensors. Additionally, a brief introduction of the electrochemical principles of glucose biosensors (including amperometric, potentiometric, and conductometric) is presented. Finally, the current status and future prospects are outlined for graphene/metal oxide nanomaterials in glucose sensing.     

Nanomaterial-based functional scaffolds for amperometric sensing of bioanalytes

Functional nanomaterials have emerged as promising candidates in the development of an amperometric sensing platform for the detection and quantification of bioanalytes. The remarkable characteristics of nanomaterials based on metal and metal oxide nanoparticles, carbon nanotubes, and graphene ensure enhanced performance of the sensors in terms of sensitivity, selectivity, detection limit, response time, and multiplexing capability. The electrocatalytic properties of these functional materials can be combined with the biocatalytic activity of redox enzymes to develop integrated biosensing platforms. Highly sensitive and stable miniaturized amperometric sensors have been developed by integrating the nanomaterials and biocatalyst with the transducers. This review provides an update on recent progress in the development of amperometric sensors/biosensors using functional nanomaterials for the sensing of clinically important metabolites such as glucose, cholesterol, lactate, and glutamate, immunosensing of cancer biomarkers, and genosensing.     

Amperometric biosensors based on electrosynthesised polymeric films

The most significant goals achieved in the course of the last decade in the design of amperometric biosensors based on redox enzymes entrapped in electrosynthesised polymeric films are reviewed. Particular emphasis is devoted to non-conducting polymers with built-in permselectivity that revealed very promising materials for designing fast-response and interference-free, H2O2 detecting, amperometric biosensors. The role of surface analytical techniques to provide structural information allowing a better understanding of polymers properties and their relationship with the ultimate performance of the final device is also outlined. The most relevant applications of amperometric biosensors based on electropolymerised films to real samples analysis are also reviewed and some possible future trends highlighted.     

Application of Amperometric Enzyme Biosensors for Wine and Must Analysis

The work presents application of amperometric biosensors based on platinum printed electrodes and immobilized enzymes alcohol oxidase, glucose oxidase and lactate oxidase for wine analysis. Created devices demonstrate wide dynamic range of work, good stability and high selectivity to the substrate, and are successfully applied for analysis of such complex mixtures as wine and must. Good correlation of the results of analysis of different wines and must obtained by amperometric biosensors and chromatography method is shown. Created biosensors can be used as a basis of commercial device for express analysis of ethanol, glucose and lactate in wine and must during its fermentation.     

Amperometric biosensors based on electrosynthesised polymeric films

The most significant goals achieved in the course of the last decade in the design of amperometric biosensors based on redox enzymes entrapped in electrosynthesised polymeric films are reviewed. Particular emphasis is devoted to non-conducting polymers with built-in permselectivity that revealed very promising materials for designing fast-response and interference-free, H₂O₂ detecting, amperometric biosensors. The role of surface analytical techniques to provide structural information allowing a better understanding of polymers properties and their relationship with the ultimate performance of the final device is also outlined. The most relevant applications of amperometric biosensors based on electropolymerised films to real samples analysis are also reviewed and some possible future trends highlighted. Received: 12 November 1999 / Revised: 10 January 2000 / Accepted: 16 January 2000     

Recent developments, characteristics, and potential applications of electrochemical biosensors.

The objective of this study is to analyze the technical importance, performance, techniques, advantages, and disadvantages of the biosensors in general and of the electrochemical biosensors in particular. A product of reaction diffuses to the transducer in the first generation biosensors (based on Clark biosensors). The mediated biosensors or second generation biosensors use specific mediators between the reaction and the transducer to improve sensitivity. The second generation biosensors involve two steps: first, there is a redox reaction between enzyme and substrate that is reoxidized by the mediator, and eventually the mediator is oxidized by the electrode. No normal product or mediator diffusion is directly involved in the third generation biosensors, direct biosensors. Based on the type of transducer, current biosensors are divided into optical, mass, thermal, and electrochemical sensors. They are used in medical diagnostics, food quality controls, environmental monitoring, and other applications. These biosensors are also grouped under two broad categories of sensors: direct and indirect detection systems. Moreover, these systems could be further grouped into continuous or batch operation. Therefore, amperometric biosensors and their current applications are focused on more in detail since they are the most commonly used biosensors in monitoring and diagnosing tests in clinical analysis. Problems related to the commercialization of medical, environmental, and industrial biosensors as well as their performance characteristics, their competitiveness in comparison to the conventional analytical tools, and their costs determine the future development of these biosensors.     

Carbon‐Nanotube Based Electrochemical Biosensors: A Review

This review addresses recent advances in carbon‐nanotubes (CNT) based electrochemical biosensors. The unique chemical and physical properties of CNT have paved the way to new and improved sensing devices, in general, and electrochemical biosensors, in particular. CNT‐based electrochemical transducers offer substantial improvements in the performance of amperometric enzyme electrodes, immunosensors and nucleic‐acid sensing devices. The greatly enhanced electrochemical reactivity of hydrogen peroxide and NADH at CNT‐modified electrodes makes these nanomaterials extremely attractive for numerous oxidase‐ and dehydrogenase‐based amperometric biosensors. Aligned CNT “forests” can act as molecular wires to allow efficient electron transfer between the underlying electrode and the redox centers of enzymes. Bioaffinity devices utilizing enzyme tags can greatly benefit from the enhanced response of the biocatalytic‐reaction product at the CNT transducer and from CNT amplification platforms carrying multiple tags. Common designs of CNT‐based biosensors are discussed, along with practical examples of such devices. The successful realization of CNT‐based biosensors requires proper control of their chemical and physical properties, as well as their functionalization and surface immobilization.     

Phenols monitoring and Hill coefficient evaluation using tyrosinase-based amperometric biosensors

Sensitive amperometric biosensors for phenols compounds, based on tyrosinase (polyphenoloxidase, PPO) immobilized on a Pt electrode in an electropolymerized poly-amphiphilic pyrrole matrix or cross-linked with glutaraldehyde, were constructed and compared. Steady-state amperometric measurements, performed at -50 mV vs. SCE in aqueous phosphate buffer containing LiClO(4) 0.1 M (pH 7) as well as in a chloroform solution containing 0.1 M C(6)H(5)CH(2)N(CH(3))(3)Cl, were used in order to compare the electroanalytical and kinetic parameters of the investigated amperometric biosensors in aqueous and nonaqueous media. It was established that the polypyrrole matrix has a higher efficiency for enzyme retention resulting in higher bioelectrode sensitivity, both in aqueous buffer (690 microA M(-1)) and in chloroform (149 microA M(-1)).     

Amperometric biosensors employing an insoluble oxidant as an interference-removing agent

A strong oxidant membrane is introduced to amperometric biosensors in order to solve the problem associated with interference from readily oxidizable species. The proposed biosensors are in planar format, and are composed of four components, i.e. a base amperometric transducer, an enzyme layer, a protecting membrane, and an oxidant membrane. In this sensor format, interfering species are removed by an oxidation reaction during their diffusion through the oxidant membrane. The oxidant membrane is introduced by dispensing a mixture of an oxidant and a polymer matrix as dissolved in an organic solvent, and thus, could be easily adapted to mass fabrication of miniature biosensors. In this work, several different reagents are examined as oxidants: BaO₂, CeO₂, MnO₂ and PbO₂. Of these, PbO₂ is shown to yield biosensors with the best performance, in terms of reducing interfering signals. Two different matrix systems are devised for use in formulating oxidant membranes: hydrophilic polyurethane (HPU) and cellulose acetate incorporating poly(ethylene glycol) (CA/PEG). While the CA/PEG-type sensor displays better sensitivity and faster response behavior, the HPU-type is shown to exhibit more pronounced interference-removing ability. The analytical utility of the proposed oxidant membrane is demonstrated by fabricating amperometric glucose and creatinine sensors as the model biosensor systems, and by investigating their response characteristics.     

Critical comparison of metallized and mediator-based carbon paste glucose biosensors

The performance of metallized carbon oxidase-based biosensors is critically compared with that of mediator-based enzyme electrodes. Dimethyl ferrocene and rhodium metal centers are used as model mediator and catalyst, respectively, in connection to carbon-paste electrode transducers and assays of glucose. The rhodium-containing bioelectrode displays enhanced selectivity (particularly improved discrimination against ascorbic acid), lower sensitivity, faster response time, greater oxygen dependence, and similar detection limit in comparison to the mediated electrode. In addition to assessing the relative merits of both strategies, the data offer useful insights into the behavior of these ‘first’- and ‘second-generation’ oxidase amperometric electrodes.     

A novel amperometric biosensor based on NiO hollow nanospheres for biosensing glucose

NiO hollow nanospheres were synthesized by controlled precipitation of metal ions with urea using carbon microspheres as templates, which were for the first time adopted to construct a novel amperometric glucose biosensor. Glucose oxidase was immobilized on the surface of hollow nanospheres through chitosan-assisted cross-linking technique. Due to the high specific active sites and high electrocatalytic activity of NiO hollow nanospheres, the constructed glucose biosensors exhibited a high sensitivity of 3.43 μA/mM. The low detection limit was estimated to be 47 μM (S/N = 3), and the Michaelis-Menten constant was found to be 7.76 mM, indicating the high affinity of enzyme on NiO hollow nanospheres to glucose. These results show that the NiO hollow nanospheres are a promising material to construct enzyme biosensors.     

Enzymatic Biosensors Based on Carbon Nanotubes Paste Electrodes

The performance of enzymatic biosensors based on the immobilization of different enzymes within a carbon nanotubes paste electrode (CNTPE) prepared by dispersion of multi‐wall carbon nanotubes (MWNT) and mineral oil is reported in this work. The strong electrocatalytic activity of carbon nanotubes towards the reduction of hydrogen peroxide and quinones and the oxidation of NADH have allowed an effective low‐potential amperometric determination of lactate, phenols, catechols and ethanol, in connection with the incorporation of lactate oxidase, polyphenol oxidase and alcohol dehydrogenase/NAD⁺, respectively, within the composite matrix. Compared to the analogous enzymatic CPEs, a great enhancement in the response is observed at the enzymatic CNTPEs. Therefore, highly sensitive lactate, phenols, catechols and alcohols biosensors without using any metal or redox mediator can be obtained with this new composite material.     

Graphene electrochemistry: fabricating amperometric biosensors

The electrochemical sensing of hydrogen peroxide is of substantial interest to the operation of oxidase-based amperometric biosensors. We explore the fabrication of a novel and highly sensitive electro-analytical biosensor using well characterised commercially available graphene and compare and contrast responses using Nafion -graphene and -graphite modified electrodes. Interestingly we observe that graphite exhibits a superior electrochemical response due to its enhanced percentage of edge plane sites when compared to graphene. However, when Nafion, routinely used in amperometric biosensors, is introduced onto graphene and graphite modified electrodes, re-orientation occurs in both cases which is beneficial in the former and detrimental in the latter; insights into this contrasting behaviour are consequently presented providing acuity into sensor design and development where graphene is utilised in biosensors.     

Sol-gel derived ceramic-carbon enzyme electrodes: Glucose oxidase as a test case

Several types of amperometric biosensors comprised of immobilized glucose oxidase in chemically-modified ceramic-carbon matrices are compared. The electrodes are comprised of several building blocks each performing a specific function. Glucose oxidase is used to catalyze the bio-oxidation of glucose; carbon powder imparts conductivity and favorable electrochemical characteristics; the Ormosil network provides rigidity and porosity; and the organic modification of the Ormosil imparts controlled surface polarity. Additionally, hydrophilic chemical modifiers are incorporated in order to control the size of the wetted, electroactive layer; high dispersion of inert metal catalysts is used to enhance hydrogen peroxide oxidation and redox mediators may be co-immobilized when oxygen independent response is desirable. The electrodes can be prepared either in the form of thick supported film, useful for disposable electrodes or as bulk-modified, disk shape electrodes, which can be used as renewable surface electrodes.