Review: Recent Developments in Enzyme-Based Biosensors for Biomedical Analysis

The need for simple, rapid, cost-effective, and portable screening methods has boosted the development of practical biosensors with applications in clinical monitoring, and diagnosis of disease. Compared with traditional analytical methods, enzyme-based bioanalytical devices have several distinct advantages such as high sensitivity and specificity, portability, cost-effectiveness, and the possibilities for miniaturization and mass production. Additionally, they can be developed for point-of-care diagnostic testing. This paper reviews recent advances in the development of enzyme biosensors, design characteristics, performances, and applications with a focus on electrochemical and optical sensors. Recent emerging technologies and innovative biosensing designs, such as nanosensors, paper based-sensors, lab-on-a-chip, biochips, and microfluidic devices are discussed. Specific applications in bioanalysis, clinical diagnosis, and pharmacology are discussed.     

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.     

Fully integrated microfluidic separations systems for biochemical analysis

Over the past decade a tremendous amount of research has been performed using microfluidic analytical devices to detect over 200 different chemical species. Most of this work has involved substantial integration of fluid manipulation components such as separation channels, valves, and filters. This level of integration has enabled complex sample processing on miniscule sample volumes. Such devices have also demonstrated high throughput, sensitivity, and separation performance. Although the miniaturization of fluidics has been highly valuable, these devices typically rely on conventional ancillary equipment such as power supplies, detection systems, and pumps for operation. This auxiliary equipment prevents the full realization of a "lab-on-a-chip" device with complete portability, autonomous operation, and low cost. Integration and/or miniaturization of ancillary components would dramatically increase the capability and impact of microfluidic separations systems. This review describes recent efforts to incorporate auxiliary equipment either as miniaturized plug-in modules or directly fabricated into the microfluidic device.     

On-chip electrochemical detection of CdS quantum dots using normal and multiple recycling flow through modes

A flexible hybrid polydimethylsiloxane (PDMS)-polycarbonate (PC) microfluidic chip with integrated screen printed electrodes (SPE) was fabricated and applied for electrochemical quantum dots (QDs) detection. The developed device combines the advantages of flexible microfluidic chips, such as their low cost, the possibility to be disposable and amenable to mass production, with the advantages of electrochemistry for its facility of integration and the possibility to miniaturize the analytical device. Due to the interest in biosensing applications in general and particularly the great demand for labelling alternatives in affinity biosensors, the electrochemistry of cadmium sulfide quantum dots (CdS QDs) is evaluated. Square wave anodic stripping voltammetry (SWASV) is the technique used due to its sensitivity and low detection limits that can be achieved. The electrochemical as well as the microfluidic parameters of the developed system are optimized. The detection of CdS QDs in the range between 50 to 8000 ng mL(-1) with a sensitivity of 0.0009 μA/(ng mL(-1)) has been achieved. In addition to the single in-chip flow through measurements, the design of a recirculation system with the aim of achieving lower detection limits using reduced volumes (25 μL) of sample was proposed as a proof-of-concept.     

Nucleic acid biosensors for environmental pollution monitoring

Nucleic acid-based biosensors are finding increasing use for the detection of environmental pollution and toxicity. A biosensor is defined as a compact analytical device incorporating a biological or biologically-derived sensing element either integrated within or intimately associated with a physicochemical transducer. A nucleic acid-based biosensor employs as the sensing element an oligonucleotide, with a known sequence of bases, or a complex structure of DNA or RNA. Nucleic acid biosensors can be used to detect DNA/RNA fragments or either biological or chemical species. In the first application, DNA/RNA is the analyte and it is detected through the hybridization reaction (this kind of biosensor is also called a genosensor). In the second application, DNA/RNA plays the role of the receptor of specific biological and/or chemical species, such as target proteins, pollutants or drugs. Recent advances in the development and applications of nucleic acid-based biosensors for environmental application are reviewed in this article with special emphasis on functional nucleic acid elements (aptamers, DNAzymes, aptazymes) and lab-on-a-chip technology.     

Microfluidic integration for electrochemical biosensor applications

Electrochemical biosensors are particularly suitable for miniaturization and integration in microfluidic devices. Applications include the detection of whole cells, cell components, proteins, and small molecules to address tasks in the fields of diagnostics and food and environmental control. Microfluidic setups range from simple channels for sample transport to channels with integrated sensing electrodes to highly sophisticated platforms with additional elements for sample preparation. The design of the microfluidics depends on both the type of detection and on the application and sample material. This review summarizes recent work on electrochemical biosensors with integrated microfluidics with the focus on developments for real sample applications, particularly those including measurements with real sample media.     

Capillary electrophoresis coupled to biosensor detection

The present review highlights some modern aspects of biosensor revelation, a detection method which has already found a large number of applications in healthcare, food industry and environmental analysis. First, the concept of bio-recognition, which is at the heart of biosensor technology, is discussed, with emphasis on host-guest-like recognition mechanisms. This detection device has been successfully coupled, in its first applications, to chromatographic columns, which allow a high resolution of complex mixtures of analytes prior to interaction with the biosensing unit. The properties of the transducing elements, which should generate a signal (e.g., electrochemical, thermal, acoustic, optical) of proper intensity and of relative fast rise, are additionally evaluated and discussed. The review then focuses on potential applications of biosensing units in capillary electrophoresis (CE) devices. CE appears to be an excellent separation methodology to be coupled to biosensor detection, since it is based on miniaturized electrophoretic chambers, fast analysis times, complete automation in sample handling and data treatment and requires extremely small sample volumes. Although only a few applications of CE-based biosensors have been described up to the present, it is anticipated that this hyphenated technique could have a considerable expansion in the coming years.     

Integration of field effect transistor-based biosensors with a digital microfluidic device for a lab-on-a-chip application

A new platform for lab-on-a-chip system is suggested that utilizes a biosensor array embedded in a digital microfluidic device. With field effect transistor (FET)-based biosensors embedded in the middle of droplet-driving electrodes, the proposed digital microfluidic device can electrically detect avian influenza antibody (anti-AI) in real time by tracing the drain current of the FET-based biosensor without a labeling process. Digitized transport of a target droplet enclosing anti-AI from an inlet to the embedded sensor is enabled by the actuation of electrowetting-on-dielectrics (EWOD). A reduction of the drain current is observed when the target droplet is merged with a pre-existing droplet on the embedded sensor. This reduction of the drain current is attributed to the specific binding of the antigen and the antibody of the AI. The proposed hybrid device consisting of the FET-based sensor and an EWOD device, built on a coplanar substrate by monolithic integration, is fully compatible with current fabrication technology for control and read-out circuitry. Such a completely electrical manner of inducing the transport of bio-molecules, the detection of bio-molecules, the recording of signals, signal processing, and the data transmission process does not require a pump, a fluidic channel, or a bulky transducer. Thus, the proposed platform can contribute to the construction of an all-in-one chip.     

Biosensors for environmental monitoring A global perspective

The intention of this article is to reflect the advances and describe the trends on biosensors for environmental applications. Biosensors are useful analytical tools for environmental monitoring, capable of providing results in real time, simple to use, portable and cost-effective. Some examples of biosensors in advanced stage of development, which have been applied to real samples, as well as of commercial devices, are given. Biosensors designed for measurement of either specific chemicals or their biological effects, such as toxicity biosensors and endocrine effect biosensors, are discussed. This overview also addresses the support provided by public institutions for biosensor research in the USA, Japan and, especially, in Europe. Future prospects of biosensor technology, with special emphasis in the development of new sensing elements, are foreseen.     

Microbial biosensors

A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed.     

Recent progress on microfluidic biosensors for rapid detection of pathogenic bacteria

Rapid on-site detection of pathogenic bacteria with high sensitivity and specificity is becoming an urgent need in public health assurance, medical diagnostics, environmental monitoring, and food safety fields. Despite being reliable and widely used, the existing methods of bacteria detection are cumbersome and time-consuming, which is not conducive to field detection. Microfluidic lab-on-a-chip technology has provided a detective tool for various analytes, due to its miniaturization, portabilit...     

Magnetic nanoparticles in microfluidic and sensing: From transport to detection

Superparamagnetic nanoparticles are attracting significant attention. Therefore, being explored in microsystems for a wide range of applications. Typical examples include lab-on-a-chip and microfluidics for synthesis, detection, separation, and transportation of different bioanalytes, such as biomolecules, cells, and viruses to develop portable, sensitive, and cost-effective biosensing systems. Particularly, microfluidic systems incorporated with magnetic nanoparticles and, in combination with magnetoresistive sensors, shift diagnostic and analytical methods to a microscale level. In this context, nanotechnology enables the miniaturization and integration of a variety of analytical functions in a single chip for manipulation, detection, and recognition of bioanalytes reliably and flexibly. In consideration of the above, recent development and benefits are elaborated herein to discuss the role of magnetic nanoparticles inside the microchannels to design highly efficient disposable point-of-care applications from transportation to the detection of bioanalytes.     

Carbon nanotubes/pentacyaneferrate-modified chitosan nanocomposites platforms for reagentless glucose biosensing

The design, characterization and applicability of a nanostructured biosensor platform are described. The biosensor is developed through the immobilization of three components: a polymeric chitosan network previously modified with a redox mediator (denoted as PCF-Pyr-Ch), an enzyme (glucose oxidase, chosen as a model) and carbon nanotubes onto a solid glassy carbon electrode (C). In order to assess the influence of the nanomaterial in the performance of the resulting analytical device, a second biosensor, free of carbon nanotubes, is developed. The characterization of both biosensing platforms was performed in aqueous phosphate buffer solutions using atomic force microscopy technique. In the presence of glucose, both systems exhibit a clear electrocatalytic activity, and glucose could be amperometrically determined at +0.35 V versus Ag/AgCl. The performance of both biosensors was evaluated in terms of sensitivity, detection limit and linear response range. Finally, the enhancement of the analytical response induced by the presence of carbon nanotubes was evaluated.     

Biosensors for the analysis of food- and waterborne pathogens and their toxins

Biosensors are devices which combine a biochemical recognition element with a physical transducer. There are various types of biosensors, including electrochemical, acoustical, and optical sensors. Biosensors are used for medical applications and for environmental testing. Although biosensors are not commonly used for food microbial analysis, they have great potential for the detection of microbial pathogens and their toxins in food. They enable fast or real-time detection, portability, and multipathogen detection for both field and laboratory analysis. Several applications have been developed for microbial analysis of food pathogens, including E. coli O157:H7, Staphylococcus aureus, Salmonella, and Listeria monocytogenes, as well as various microbial toxins such as staphylococcal enterotoxins and mycotoxins. Biosensors have several potential advantages over other methods of analysis, including sensitivity in the range of ng/mL for microbial toxins and <100 colony-forming units/mL for bacteria. Fast or real-time detection can provide almost immediate interactive information about the sample tested, enabling users to take corrective measures before consumption or further contamination can occur. Miniaturization of biosensors enables biosensor integration into various food production equipment and machinery. Potential uses of biosensors for food microbiology include online process microbial monitoring to provide real-time information in food production and analysis of microbial pathogens and their toxins in finished food. Biosensors can also be integrated into Hazard Analysis and Critical Control Point programs, enabling critical microbial analysis of the entire food manufacturing process. In this review, the main biosensor approaches, technologies, instrumentation, and applications for food microbial analysis are described.     

Biosensors based on cholinesterase inhibition for insecticides, nerve agents and aflatoxin B1 detection (review)

The present review reports the research carried out during last 9 years on biosensors based on cholinesterase inhibition for nerve agents, organophosphorus and carbammic insecticides, and aflatoxin B₁ detection. Relative applications in environmental and food areas are also reported. Special attention is paid to the optimization of parameters such as enzyme immobilization, substrate concentration, and incubation time in the case of reversible inhibition by aflatoxin B₁ or irreversible inhibition by organophosphorus and carbamic insecticides, and nerve agents in order to optimize and improve the analytical performances of the biosensor. Evaluation of selectivity of the system is also discussed.     

Increasing the detection speed of an all-electronic real-time biosensor

Biosensor response time, which depends sensitively on the transport of biomolecules to the sensor surface, is a critical concern for future biosensor applications. We have fabricated carbon nanotube field-effect transistor biosensors and quantified protein binding rates onto these nanoelectronic sensors. Using this experimental platform we test the effectiveness of a protein repellent coating designed to enhance protein flux to the all-electronic real-time biosensor. We observe a 2.5-fold increase in the initial protein flux to the sensor when upstream binding sites are blocked. Mass transport modelling is used to calculate the maximal flux enhancement that is possible with this strategy. Our results demonstrate a new methodology for characterizing nanoelectronic biosensor performance, and demonstrate a mass transport optimization strategy that is applicable to a wide range of microfluidic based biosensors.     

Recent advances in nucleic acid amplification-based optical biosensors for disease diagnosisEI北大核心CSCD

Optical biosensors have been widely used in the detection of biomarkers due to their advantages of simple operationquick responsehigh sensitivity and visualization. When constructing optical biosensors nucleic acid amplification technology can be used to improve the analytical performance of optical biosensor which can further realize the highly sensitive detection of biomarkers and provide more accurate information for disease diagnosis. In this reviewrecent advances in nucleic acid amplification-based optical biosensors for disease diagnosis were reviewed the possible problems may exist in practical applications and future development trends were proposed. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

光电化学型半导体生物传感器

光电化学型半导体生物传感器是一种利用半导体的光电特性来检测与光生电流或光生电压相关的待测物质浓度及生化过程参数的分析新技术。随着新兴半导体功能材料及相关加工技术的不断涌现,光电化学型半导体生物传感器已在微型化、集成化、多点及多参数测量方面显现出优势、有望在复杂体系中实现在线高灵敏、快速测定,在生物、医药、环境监测、食品等领域显示出广阔的应用前景。本文主要介绍了光电化学型半导体传感器的基本原理、特点及近几年的研究进展,并对其发展前景做了展望。     

Chitosan-mediated in situ biomolecule assembly in completely packaged microfluidic devices

We report facile in situ biomolecule assembly at readily addressable sites in microfluidic channels after complete fabrication and packaging of the microfluidic device. Aminopolysaccharide chitosan's pH responsive and chemically reactive properties allow electric signal-guided biomolecule assembly onto conductive inorganic surfaces from the aqueous environment, preserving the activity of the biomolecules. A transparent and nonpermanently packaged device allows consistently leak-free sealing, simple in situ and ex situ examination of the assembly procedures, fluidic input/outputs for transport of aqueous solutions, and electrical ports to guide the assembly onto the patterned gold electrode sites within the channel. Both in situ fluorescence and ex situ profilometer results confirm chitosan-mediated in situ biomolecule assembly, demonstrating a simple approach to direct the assembly of biological components into a completely fabricated device. We believe that this strategy holds significant potential as a simple and generic biomolecule assembly approach for future applications in complex biomolecular or biosensing analyses as well as in sophisticated microfluidic networks as anticipated for future lab-on-a-chip devices.