Nanobioelectroanalysis Based on Carbon/Inorganic Hybrid Nanoarchitectures

The emergence of nanotechnology has opened new horizons for electrochemical biosensors. This review highlights new concepts for electrochemical biosensors based on different carbon/inorganic hybrid nanoarchitectures. Particular attention will be given to hybrid nanostructures involving 1‐ or 2‐dimensional carbon nanotubes or graphene along with inorganic nanoparticles (gold, platinum, quantum dot (QD), metal oxide). Latest advances (from 2007 onwards) in electrochemical biosensors based on such hybrids of carbon/inorganic‐nanomaterial heterostructures are discussed and illustrated in connection to enzyme electrodes for blood glucose or immunoassays of cancer markers. Several strategies for using carbon/inorganic nanohybrids in such bioaffinity and biocatalytic sensing are described, including the use of hybrid nanostructures for tagging or modifying electrode transducers, use of inorganic nanomaterials as surface modifiers along with carbon nanomaterial label carriers, and carbon nanostructure‐based electrode transducers along with inorganic amplification tags. The implications of these nanoscale bioconjugated hybrid materials on the development of modern electrochemical biosensors are discussed along with future prospects and challenges.     

Electrochemical biosensing based on noble metal nanoparticles

The interest in the fabrication of electrochemical biosensors with high sensitivity, selectivity and efficiency is rapidly growing. In recent years, noble metal nanoparticles (NMNPs), with extraordinary conductivity, large surface-to-volume ratio and biocompatibility, have been extensively employed for developing novel electrochemical sensing platforms and improving their performances. Through distinct surface modification strategies (e.g. self-assembly, layer-by-layer, hybridization and sol-gel technology), NMNPs provide well control over the microenvironment of biological molecules retaining their activity, and facilitate the electron transfer between the redox center of biomolecules and electrode surface. Moreover, NMNPs have been involved into biorecognition events (e.g. immunoreactions, DNA hybridization and ligand-receptor interactions) by conjugating with various biomolecules, chemical labels and other nanomaterials, achieving the signal transduction and amplification. The aim of this review is to summarize different strategies for NMNP-based signal amplification, as well as to provide a snapshot of recent advances in the design of electrochemical biosensing platforms, including enzyme/protein sensors focused on their direct electrochemistry on NMNP-modified electrode surface; immunosensors and gene sensors in which NMNPs not only participate into biorecognition, but also act as electroactive tags to enhance the signal output. In addition, NMNP alloy-based multifunctional electrochemical biosensors are briefly introduced in terms of their unique heterostructures and properties.

Plasmonic photoelectrochemical reactions on noble metal electrodes of nanostructures

Plasmonic noble metal nanostructures have been targeted due to their strong surface plasmon resonance at photoelectrochemical interfaces. Recently, it has been concluded that, the plasmonic noble metal nanostructures on photoexcitation permit the transfer of effective hot carriers (hot electron/hole pair) to nearby adsorbed molecules where, the transformed hot carriers can efficiently decrease the activation barrier of a reaction. In this review, our recent achievements in the plasmon-mediated chemical reactions of organic molecules such as para-aminothiophenol, substituted para-aminothiophenol and para-nitrothiophenol at nanostructures modified noble metal electrodes using surface enhanced Raman spectroscopy, electrochemical methods, and theoretical calculations will be discussed.     

贵金属在Ag_2S纳米颗粒中由内向外的迁移现象

纳米颗粒具有明显区别于块体材料的新奇特性,本文利用透射电镜观察,描述并讨论一种发生在贵金属(Au、Ag、Pd和Pt)和硫化银(Ag_2S)构成的核壳结构纳米颗粒中的有趣现象,即贵金属在Ag_2S纳米颗粒中由内向外的迁移。迁移可在室温下进行,其最终结果使最初的核壳结构颗粒演变成由贵金属和Ag_2S构成的异质纳米二聚体结构,如Au-Ag_2S、Ag-Ag_2S、PdAg_2S和Pt-Ag_2S。电镜表征表面实验条件下贵金属在Ag_2S的迁移类似于一种整体迁移的模式且迁移过程中伴随着颗粒形貌结构的演变。贵金属在Ag_2S中的经空位互换的扩散机制或半导体纳米颗粒的自纯化机制可以用来解释这种迁移现象。     

Fabrication of monometallic (Co,Pd, Pt,Au) and bimetallic (Pt/Au,Au/Pt) thin films with hierarchical architectures as electrocatalysts

Co thin films with novel hierarchical structures were controllably fabricated by simple electrochemical deposition in the absence of hard and soft templates, which were used as sacrificial templates to further prepare noble metal (Pd, Pt, Au) hierarchical micro/nanostructures via metal exchange reactions. SEM characterization demonstrated that the resulting noble metal thin films displayed hierarchical architectures. The as-prepared noble metal thin films could be directly used as the anode catalysts for the electro-oxidation of formic acid. Moreover, bimetallic catalysts (Pt/Au, Au/Pt) fabricated based on the monometallic Au, Pt micro/nanostructures exhibited the higher catalytic activity compared to the previous monometallic catalysts.     

Recent advances in ZnO nanostructures and thin films for biosensor applications: Review

Biosensors have shown great potential for health care and environmental monitoring. The performance of biosensors depends on their components, among which the matrix material, i.e., the layer between the recognition layer of biomolecule and transducer, plays a crucial role in defining the stability, sensitivity and shelf-life of a biosensor. Recently, zinc oxide (ZnO) nanostructures and thin films have attracted much interest as materials for biosensors due to their biocompatibility, chemical stability, high isoelectric point, electrochemical activity, high electron mobility, ease of synthesis by diverse methods and high surface-to-volume ratio. ZnO nanostructures have shown the binding of biomolecules in desired orientations with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes ZnO nanostructures suitable candidate for future small integrated biosensor devices. This review highlights recent advances in various approaches towards synthesis of ZnO nanostructures and thin films and their applications in biosensor technology.     

Synthesis of Au–ZnS hybrid nanostructures and their application for electrochemical biosensor

Au–ZnS core–shell nanostructures were grown onto the transparent indium tin oxide (ITO) thin film-coated glass surface by successive electrodeposition of Au and ZnS in cyclic voltammetry. The resulting hybrid nanostructures were characterized using scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, and electrochemical impedance spectroscopy. The glucose oxidase (GOD) was immobilized onto the surface of the Au–ZnS hybrid nanostructures in silica sol–gel network. Furthermore, the Au–ZnS nanostructures demonstrate an enhanced direct electron transfer between GOD and the electrode due to their unique chemical and electrocatalytic properties and their synergy effect. The analytical performance of the GOD-based electrode was improved greatly compared with that of ITO substrate modified by Au or ZnS nanostructures alone. The proposed enzyme electrode based on Au–ZnS hybrid nanomaterials displays high sensitivity and wide linear range in the determination of glucose. The Au–ZnS hybrid nanostructures have potential for “green chemistry” application in the fabrication of enzyme-based electrochemical biosensors.     

基于局域表面等离子体共振效应的光学生物传感器*

贵金属纳米粒子表现出许多常规块体材料所不具备的优异性能,其中局域表面等离子体共振 (LSPR) 特性是研究热点之一。LSPR 的形状和位置与纳米粒子的组成、大小、形状、介电性质以及局域介质环境密切相关。基于这一特性,贵金属纳米粒子已广泛应用于光学生物传感器、光过滤器和表面增强光谱等领域。本文对各种结构的贵金属纳米粒子的制备方法及其在光学生物传感器中的应用进行了综述,并对 LSPR 纳米传感器的未来发展前景做了展望。     

基于新型纳米传感材料的DNA生物传感器的应用

DNA是构建纳米技术和生物传感技术新设备的良好构建体.DNA生物传感器由于具有灵敏度高、选择性好等特点,近年来获得了飞速发展.研究发现,金属纳米粒子(MNPs)、碳基纳米材料等一系列纳米材料在传感器设计中提高了电化学DNA传感器的传感性能.本文侧重介绍了场效应晶体管、石墨烯、碳纳米管等新型纳米传感材料,以及基于这些材料...     

Customized Bio‐functionalization of Nanocomposite Carbon Paste Electrodes for Electrochemical Sensing: A Mini Review

Over the past few decades, the (bio)functionalization of carbon nanomaterials (CNMs), such as nanohorns, carbon nanotubes, graphene, graphite and related with a wide range of (bio)modifiers have been extensively studied for their incorporation on different pure metal or carbon electrode surfaces via drop‐casting. However, CNMs are also shown to be important functional additives for polymers, having great potential to produce rigid nanocomposite materials with a range of enhanced properties, including mechanical, optical, electrical, thermal and electrochemical. The high malleability derived from the host polymer allows alternative strategies that can be carried out in order to incorporate different types of (bio)modifiers in/on/into a polymeric nanocomposite electrode. Accordingly, this mini review overviews the main methodologies used for the bio‐functionalization of electrochemical transducers based on nanocomposite carbon paste electrodes (NC‐CPEs). Additionally, the most extensively (bio)modifiers used in electrochemical (bio)sensing, together with their various electrocatalytical performance are also discussed, fact that might serve as a general outlook for planning further research.     

非酶葡萄糖传感器电极材料构建策略

电化学传感器因具有灵敏度高、检测限低等优点而得到广泛应用,将非酶电化学传感器应用于葡萄糖浓度的检测具备重要的研究价值。以金属有机骨架、碳材料和导电聚合物为基底与金属及其衍生物复合,构建的纳米复合材料修饰电极对于葡萄糖的检测具有极高的灵敏度、较低的检测限和快速响应的能力,可应用于实际样品的检测。本文综述了近年来非酶葡萄糖电化学传感器的研究进展,通过对纳米复合材料的性能比较,为非酶葡萄糖传感器的构建提供思路。     

Electrochemical biosensors based on Ti3C2Tx MXene: future perspectives for on-site analysis

MXenes are recently developed two-dimensional layered materials composed of early transition metal carbides and/or nitrides that provide unique characteristics for biosensor applications. This review presents the recent progress made on the usage and applications of MXenes in the field of electrochemical biosensors, including microfluidic biosensors and wearable microfluidic biosensors, and highlights the challenges with possible solutions and future needs. The multilayered configuration and high conductivity make these materials as an immobilization matrix for the biomolecule immobilization with activity retention and to be explored in the fabrication of electrochemical sensors, respectively. First, how the MXene nanocomposite as an electrode modifier affects the sensing performance of the electrochemical biosensors based on enzymes, aptamer/DNA, and immunoassays is well described. Second, recent developments in MXene nanocomposites as wearable biosensing platforms for the biomolecule detection are highlighted. This review pointed out the future concerns and directions for the use of MXene nanocomposites to fabricate advanced electrochemical biosensors with high sensitivity and selectivity. Specifically, possibilities for developing microfluidic electrochemical sensors and wearable electrochemical microfluidic sensors with integrated biomolecule detection are emphasized.     

Nanomaterials as Pseudocatalysts in the Construction of Electrochemical Nonenzymatic Sensors for Healthcare: A Review

Enzymes, primarily different types of oxidases and most commonly peroxidase, are often used in the construction of biosensors. Enzymatic biosensors, due to their small size, easy to handle construction, accuracy and specificity, are powerful healthcare tools commonly used for the diagnosis of diseases for more than 20 years. Unfortunately, the loss of enzymatic activity during the immobilization of enzymes into biosensors has been a recent major problem. Hence, nonenzymatic electrochemical sensors based on organic and inorganic nanostructures have gained great attention in the last few years. In this short review, different types of nanostructures and nanocomposites and their practical applications in the construction of nonenzymatic electrochemical sensors in healthcare and diagnosis are described and summarized.     

Electrochemical Biosensing Systems Based on Carbon Nanotubes and Carbon Nanofibers

Abstract

Carbon nanomaterials are in the forefront of research in a variety of chemical and physical disciplines. Of these, certain nanostructures seem to be suitable for the development of electrochemical biosensors. In particular carbon nanotubes, and carbon nanofibers have specific chemical and physical characteristics that lent them ideal for the development of biosensors with unique analytical characteristics. In particular, their conductivity, surface area, inherent and induced chemical functionalities, and biocompatibility provide the grounds for the development of a new era of electrochemical biosensors. In this review, we will examine the recent developments of biosensor design based on these new nanostructures.     

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。     

Electrochemical Properties of Highly Sensitive and Selective CuO Nanostructures Based Neurotransmitter Dopamine Sensor

In this article, electrochemical properties of CuO nanostructures based dopamine (DA) sensor was investigated. The morphology, structure, optical, and compositional properties of the CuO nanostructures were characterized by using SEM, XRD, UV‐Vis, and XPS techniques. The electrochemical properties were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The CV results indicate that biosensors based on CuO nanostructures exhibit a high selectivity and sensitivity of 0.1975 μA μM^–1 toward DA and effectively avoids the interference of ascorbic acid (AA) and uric acid (UA). The obtained EIS spectra for CuO sensors were analysed using an electrical equivalent circuit to understand the bulk and surface response via the capacitive and resistive parameters. The EIS measurement also leads to the direct determination of parameters like series resistance and ion diffusion phenomena at electrode‐electrolyte interface. The experimental CV and EIS results along with their analysis will have a significant impact on understanding the mechanism of high sensitivity and selectivity performance of CuO based sensors. This study may also lay the basis for efficient characterization of biosensors by coupling both the CV and EIS characterization techniques.     

Self‐Templating Synthesis of Hollow Co3O4 Microtube Arrays for Highly Efficient Water Electrolysis

In spite of recent advances in the synthesis of hollow micro/nanostructures, the fabrication of three‐dimensional electrodes on the basis of these structures remains a major challenge. Herein, we develop an electrochemical sacrificial‐template strategy to fabricate hollow Co₃O₄ microtube arrays with hierarchical porosity. The resultant unique structures and integrated electrode configurations impart enhanced mass transfer and electron mobility, ensuring high activity and stability in catalyzing oxygen and hydrogen evolution reactions. Impressively, the apparent performance can rival that of state‐of‐the‐art noble‐metal and transition‐metal electrocatalysts. Furthermore, this bifunctional electrode can be used for highly efficient overall water splitting, even competing with the integrated performance of Pt/C and IrO₂/C.     

聚苯胺/贵金属复合纳米材料的可控合成及催化应用

导电高分子/贵金属复合纳米材料因其在催化、传感、表面增强拉曼、光热治疗等诸多领域的应用前景而受到广泛关注.本文主要介绍我们课题组近年来利用可控合成策略制备的负载型和包埋型两种结构聚苯胺/贵金属复合纳米材料,以及利用复合纳米材料的结构和功能特性,对其在多相催化领域的应用、结构与催化性能之间构效关系的探索.     

Bacterial synthesized metal and metal salt nanoparticles in biomedical applications: An up and coming approach

In the present scenario, metal nanoparticles have elicited a great deal of interest in biomedical applications because of their unique properties and antimicrobial potentials. Over the past few years, the green nanotechnology has materialized as a momentous approach for the synthesis and fabrication of noble metal salt and metal nanoparticles. The green route synthesis exploits diverse reducing and stabilizing agents from bacterial resources for the successful synthesis of metal nanoparticles. This review mainly focuses on the biosynthesis of the most commonly studied metal and metal salt nanoparticles such as gold, silver, platinum, palladium, copper, cadmium, titanium oxide, zinc oxide, zinc sulphate, cadmium sulphide and many more. These noble nanoparticles can be exploited in pharmaceutical industry as antimicrobial and anti-biofilm agents, targeted delivery of anticancer drugs, biosensors, etc.     

金属氧化物纳米材料的电化学合成与形貌调控研究进展

金属氧化物纳米材料因其丰富的形貌、独特的性能、广泛的应用成为材料合成领域研究的热点.调控金属氧化物纳米材料的形貌对于调变其性能、拓展其应用空间具有重要意义.电化学方法由于操作简单易控、方法灵活多变,因此成为调控金属氧化物形貌的常用方法.本文综述了近年来我们在金属氧化物纳米材料的电化学合成与形貌调控方面已取得的研究结果;总结了不同金属氧化物在电化学过程中晶体生长机制和形貌调控的规律,为实现功能材料的定向合成奠定了基础.