Microfluidic-integrated biosensors: Prospects for point-of-care diagnostics

There is a growing demand to integrate biosensors with microfluidics to provide miniaturized platforms with many favorable properties, such as reduced sample volume, decreased processing time, low cost analysis and low reagent consumption. These microfluidics-integrated biosensors would also have numerous advantages such as laminar flow, minimal handling of hazardous materials, multiple sample detection in parallel, portability and versatility in design. Microfluidics involves the science and technology of manipulation of fluids at the micro- to nano-liter level. It is predicted that combining biosensors with microfluidic chips will yield enhanced analytical capability, and widen the possibilities for applications in clinical diagnostics. The recent developments in microfluidics have helped researchers working in industries and educational institutes to adopt some of these platforms for point-of-care (POC) diagnostics. This review focuses on the latest advancements in the fields of microfluidic biosensing technologies, and on the challenges and possible solutions for translation of this technology for POC diagnostic applications. We also discuss the fabrication techniques required for developing microfluidic-integrated biosensors, recently reported biomarkers, and the prospects of POC diagnostics in the medical industry.     

Semiconductor quantum dots for in vitro diagnostics and cellular imaging

The need for companion diagnostics, point-of-care testing (POCT) and high-throughput screening in clinical diagnostics and personalized medicine has pushed the need for more biological information from a single sample at extremely low concentrations and volumes. Optical biosensors based on semiconductor quantum dots (QDs) can answer these requirements because their unique photophysical properties are ideally suited for highly sensitive multiplexed detection. Many different biological systems have been successfully scrutinized with a large variety of QDs over the past decade but their future as widely applied commercial biosensors is still open. In this review, we highlight recent in vitro diagnostic and cellular imaging applications of QDs and discuss milestones and obstacles on their way toward integration into real-life diagnostic and medical applications.     

Biosensors as diagnostic tools in clinical applications

Nowadays, the development of new technological solutions in the medical field, in particular biosensors, is a priority and a ground for great scientific and financial investment. From glucose sensors to highly sensible and more precise molecular tools, this biotechnological field has gone through an exponential growth, but still the applications are very limited to the future potential foreseen in the medical area. In the last decade, the advances in the genomic field have permitted the identification of specific biomarkers related to certain diseases, becoming one of the main approaches used in clinical diagnosis. Biomarkers have different clinical values, in the sense that they may provide preventive, predictive, prognostic and therapeutic response related information, not being exclusively used for diagnostic purposes, but also be applied in health management and disease treatment. Therefore, biomarkers allied with biosensors have the potential to revolutionize the way healthcare is managed. The vast choice of bioreceptors such as nucleic acids, antibodies, antigens, enzymes and even whole cells, consents the diagnosis of diseases ranging from viral and bacterial infections to cancer and metabolism disorders. The major appeal of these sensing platforms is that it provides a fast, cost-effective, reliable, highly sensitive and easy way to obtain an earlier clinical diagnosis, which can significantly affect the survival rate or patient's prognosis. This review will explore some of the most recent devices available and its clinical applications.     

生物芯片、生物传感器和生物信息学

近年来,在生物技术和医学研究领域涌现出了许多新技术平台,其中就包括生物芯片技术和生物传感器技术。生物芯片和生物传感器的构建都必须以生物信息学为基础,而两种技术平台应用所得出的数据和结果又反过来大大丰富和充实了生物信息学本身。本分析概述了生物芯片和生物传感器两种技术平台以及生物信息学,对三之间的相互关系进行了讨论。     

Amperometric enzyme biosensors: Past,present and future

Three groups of the amperometric biosensors such as unmediated, mediated and based on direct transfer of electrons have been thoroughly described, and their advantages and disadvantages were shown. The amperometric biosensors are mostly utilized in commercial devices since they are studied to a greater extent and have some advantages. The modern commercial systems based on amperometric biosensors and its applications have been presented. The major field of employing biosensors is medical diagnostics where numerous commercial devices are currently functioning.     

Market analysis of biosensors for food safety

This paper is presented as an overview of the pathogen detection industry. The review includes pathogen detection markets and their prospects for the future. Potential markets include the medical, military, food, and environmental industries. Those industries combined have a market size of $563 million for pathogen detecting biosensors and are expected to grow at a compounded annual growth rate of 4.5%. The food market is further segmented into different food product industries. The overall food-pathogen testing market is expected to grow to $192 million and 34 million tests by 2005. The trend in pathogen testing emphasizes the need to commercialize biosensors for the food safety industry as legislation creates new standards for microbial monitoring. With quicker detection time and reusable features, biosensors will be important to those interested in real time diagnostics of disease causing pathogens. As the world becomes more concerned with safe food and water supply, the demand for rapid detecting biosensors will only increase.     

Exploring biomolecular recognition using optical biosensors.

Understanding the basic forces that determine molecular recognition helps to elucidate mechanisms of biological processes and facilitates discovery of innovative biotechnological methods and materials for therapeutics, diagnostics, and separation science. The ability to measure interaction properties of biological macromolecules quantitatively across a wide range of affinity, size, and purity is a growing need of studies aimed at characterizing biomolecular interactions and the structural elements that drive them. Optical biosensors have provided an increasingly impactful technology for such biomolecular interaction analyses. These biosensors record the binding and dissociation of macromolecules in real time by transducing the accumulation of mass of an analyte molecule at the sensor surface coated with ligand molecule into an optical signal. Interactions of analytes and ligands can be analyzed at a microscale and without the need to label either interactant. Sensors enable the detection of bimolecular interaction as well as multimolecular assembly. Most notably, the method is quantitative and kinetic, enabling determination of both steady-state and dynamic parameters of interaction. This article describes the basic methodology of optical biosensors and presents several examples of its use to investigate such biomolecular systems as cytokine growth factor-receptor recognition, coagulation factor assembly, and virus-cell docking.     

Plasmon-Enhanced Fluorescence Biosensors: a Review

Surfaces of metallic films and metallic nanoparticles can strongly confine electromagnetic field through its coupling to propagating or localized surface plasmons. This interaction is associated with large enhancement of the field intensity and local optical density of states which provides means to increase excitation rate, raise quantum yield, and control far field angular distribution of fluorescence light emitted by organic dyes and quantum dots. Such emitters are commonly used as labels in assays for detection of chemical and biological species. Their interaction with surface plasmons allows amplifying fluorescence signal (brightness) that accompanies molecular binding events by several orders of magnitude. In conjunction with interfacial architectures for the specific capture of target analyte on a metallic surface, plasmon-enhanced fluorescence (PEF) that is also referred to as metal-enhanced fluorescence (MEF) represents an attractive method for shortening detection times and increasing sensitivity of various fluorescence-based analytical technologies. This review provides an introduction to fundamentals of PEF, illustrates current developments in design of metallic nanostructures for efficient fluorescence signal amplification that utilizes propagating and localized surface plasmons, and summarizes current implementations to biosensors for detection of trace amounts of biomarkers, toxins, and pathogens that are relevant to medical diagnostics and food control.

     

Recent advances in the development of bioelectronic nose

The olfactory system has the ability to discriminate and identify thousands of odorant compounds at very low concentrations. Recently, many researchers have been trying to develop artificial sensing devices that are based on the olfactory system. A bioelectronic nose, which uses olfactory receptors (ORs) as sensing elements, would benefit naturally optimized molecular recognition. Accordingly, ORs can be effectively used as a biological element in bioelectronic noses. Bioelectronic nose can be classified into cell-based and protein-based biosensors. The cell-based biosensor uses living cells that express olfactory receptors as the biological sensing elements and the protein-based biosensor uses the olfactory receptor protein. The binding of odorant molecules to the ORs can be measured using various methods such as piezoelectric, optic, and electric devices. Thus, bioelectronic nose can be developed by combining the biological sensing elements with these non-biological devices. The application of bioelectronic nose in a wide range of different scientific and medical fields is essentially dependent on the development of highly sensitive and selective biosensors. These sensor systems for the rapid detection of specific odorants are crucial for environmental monitoring, anti-bioterrorism, disease diagnostics, and food safety. In this article, we reviewed recent advances in the development of bioelectronic nose.     

Cancer proteomics: many technologies,one goal

A major goal of the National Cancer Institute is to alleviate patient pain, suffering and death associated with cancer by the year 2015. This goal does not insinuate a cure for cancer, but rather the development of diagnostics and therapeutics that will eventually decrease cancer morbidity and mortality. A part of meeting this goal is to leverage the enormous data-gathering capabilities of proteomic technologies to discover disease-specific biomarkers in serum, plasma, urine, tissues and other biologic samples. The rapid advance in available technologies that have been spurred by the -omics era, has enabled biologic samples to be surveyed for biomarkers in ways never before possible. However, it is not yet clear which specific technologies will be the most successful. Therefore, proteomic laboratories within the National Cancer Institute are taking a multipronged approach to identify disease-specific biomarkers. This review discusses some of these approaches in their context of meeting the National Cancer Institute’s 2015 goal.     

Cancer proteomics: many technologies, one goal

A major goal of the National Cancer Institute is to alleviate patient pain, suffering and death associated with cancer by the year 2015. This goal does not insinuate a cure for cancer, but rather the development of diagnostics and therapeutics that will eventually decrease cancer morbidity and mortality. A part of meeting this goal is to leverage the enormous data-gathering capabilities of proteomic technologies to discover disease-specific biomarkers in serum, plasma, urine, tissues and other biologic samples. The rapid advance in available technologies that have been spurred by the -omics era, has enabled biologic samples to be surveyed for biomarkers in ways never before possible. However, it is not yet clear which specific technologies will be the most successful. Therefore, proteomic laboratories within the National Cancer Institute are taking a multipronged approach to identify disease-specific biomarkers. This review discusses some of these approaches in their context of meeting the National Cancer Institute's 2015 goal.     

Application of nanotechnology in biomedicine

Nanotechnology is the development of engineered devices at the atomic, molecular and macromolecular level in nanometer range. Nanoparticles have potential application in medical field including diagnostics and therapeutics. Nanotechnology devices are being developed for diagnosis of cancer and infectious diseases which can help in early detection of the disease. Advances in nanotechnology also proved beneficial in therapeutic field such as drug discovery, drug delivery and gene/protein delivery. Nanoparticles can be constructed by various methodology so that effect can be targeted at desired site. In this review, some of the applications of nanoparticles in medicine as diagnostics and therapeutics which can be employed safely at the clinical level have been described. On other hand, as the particles become generally smaller their likehood of causing harm to the lung increases. Therefore, there is a need to study safety of nanoparticles.     

Urine as a source for clinical proteome analysis: From discovery to clinical application

The success of clinical proteome analysis should be assessed based on the clinical impact following implementation of findings. Although there have been several technological advancements in mass spectrometry in the last years, these have not resulted in similar advancements in clinical proteomics. In addition, application of proteomic biomarkers in clinical diagnostics and practical improvement in the disease management is extremely rare. In this review, we discuss the relevant issues associated with identification of robust biomarkers of clinical value. Urine appears to be an ideal source of biomarkers, for theoretical, methodological, and practical reasons. Therefore, this review is focused on the search for biomarkers in urine within the last decade. Urine can be used for non-invasive assessment of a variety of diseases including those affecting the urogenital tract and also other pathologies such as cardiovascular disease or appendicitis. We also discuss the importance of data validation, an essential step in translating biomarkers into the clinical practice. Furthermore, we examine several examples of apparently successful proteomic biomarker discovery studies and their implications for disease diagnosis, prognosis, and therapy evaluation. We also discuss some current challenges in this field and reflect on future research prospects. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge.     

Current and emerging commercial optical biosensors.

The field of commercial optical biosensors is rapidly evolving, with new systems and detection methods being developed each year. This review outlines the currently available biosensor hardware and highlights unique features of each platform. Affinity-based biosensor technology, with its high sensitivity, wide versatility and high throughput, is playing a significant role in basic research, pharmaceutical development, and the food and environmental sciences. Likewise, the increasing popularity of biosensors is prompting manufacturers to develop new instrumentation for dedicated applications. We provide a preview of some of the emerging commercial systems that are dedicated to drug discovery, proteomics, clinical diagnostics and routine biomolecular interaction analysis.     

在医疗保健领域开发和使用生物标记物的政策性问题

描述了发展中的生物标记物所处的科学、产业、监管和医疗保健管理系统背景,指出了可能阻碍生物标记物研究、发现、发展、商业化及最终临床应用的一些障碍,聚焦了医疗保健中基于生物标记物的诊断方法和医学检验的应用,探索了生物标记物在改良药物开发中的应用。     

Potential diagnostic applications of biosensors: current and future directions

This review describes recent advances in biosensors of potential clinical applications. Biosensors are becoming increasingly important and practical tools in pathogen detection, molecular diagnostics, environmental monitoring, food safety control as well as in homeland defense. Electrochemical biosensors are particularly promising toward these goals arising due to several combined advantages including low-cost, operation convenience, and miniaturized devices. We review the clinical applications of electrochemical biosensors based on a few selected examples, including enzyme-based biosensors, immunological biosensors and DNA biosensors.     

The application of ultrasound as a rapid method to provide DNA fragments suitable for detection by DNA biosensors

Contamination of food and water supplies by microorganisms such as Escherichia coli, the need for point-of-care bedside analysis of biological samples, and concerns about terrorist attacks using biological organisms, have made the development of fast, reliable, and sensitive analytical methodologies for use in monitoring of pathogens very important. With a variety of biosensors being developed for extremely sensitive and rapid nucleic acid diagnostics, it has become even more important to shift focus towards creation of methods to decrease the amount of time and effort necessary for sample preparation. The application of ultrasound has the potential to create DNA fragments from genomic material with lengths that are suitable for determination using biosensors and microarrays. For example, application of 85 W power at a frequency of 20 kHz can produce a preponderance of fragments of 100-400 base pairs (bp) within several seconds, and sample processing can lead to over 75% conversion from genomic material to fragments in times of 20-30 s. A proportion of these fragments are in a single-stranded state and are suitable for hydridization with immobilized single-stranded DNA probe oligonucleotides using a fiber optic biosensor. Control of factors such as salt concentration, exposure time, ultrasound power, and the initial temperature of the solution, can affect the length and form (single- or double-stranded) of DNA fragments that are generated by ultrasound, and average fragment length can be adjusted by selection of these operating parameters.     

Monitoring oxidative stress biomarkers in the lipidome: is there a roadmap for "human inspection"?

Oxidative stress is more and more recognized as the underlying motif for a broad variety of diseases including cancer. Medicine faces the paramount task to develop better diagnostic tools and drug treatment prediction models in the future to significantly enhance the quality of life. Special interest will focus on earlystage disease biomarkers and biomarkers that could predict healing success at the earliest time point after the treatment started. The accelerated formation of so-called reactive oxygen species (ROS) is becoming widely regarded as the underlying process associated with many diseases like myocardial infarction, Alzheimer's, Parkinson's and kidney disease, etc. Once generated within cells and tissues, ROS can react with a variety of cellular metabolites like fatty acids, proteins or DNA. This review investigates the possibilities for various oxidized metabolites as well as proteomics, genomics and bioimaging biomarkers to serve as early-stage disease biomarkers or biomarkers for drug treatment success. We also assess the value of a step-by-step or cascade biomarker approach as a new paradigm in medical diagnostics. Examples are given for possible analytical methodology and tools as well as statistical methods that could be applied. Such an approach may straighten the road toward new medical diagnostics and treatment regimes, which ultimately could lead to a significantly enhanced medical service for patients suffering from chronic and debilitating or deadly diseases including cancer. Examples from recent research are given to show the progress and possibilities for the proposed model.     

Development of biosensors for cancer clinical testing

Biosensors are devices that combine a biochemical recognition/binding element (ligand) with a signal conversion unit (transducer). Biosensors are already used for several clinical applications, for example for electrochemical measurement of blood glucose concentrations. Application of biosensors in cancer clinical testing has several potential advantages over other clinical analysis methods including increased assay speed and flexibility, capability for multi-target analyses, automation, reduced costs of diagnostic testing and a potential to bring molecular diagnostic assays to community health care systems and to underserved populations. They have the potential for facilitating Point of Care Testing (POCT), where state-of-the-art molecular analysis is carried out without requiring a state-of-the-art laboratory. However, not many biosensors have been developed for cancer-related testing. One major challenge in harnessing the potential of biosensors is that cancer is a very complex set of diseases. Tumors vary widely in etiology and pathogenesis. Oncologists rely heavily on histological characterization of tumors and a few biomarkers that have demonstrated clinical utility to aid in patient management decisions. New genomic and proteomic molecular tools are being used to profile tumors and produce "molecular signatures." These signatures include genetic and epigenetic signatures, changes in gene expression, protein profiles and post-translational modifications of proteins. These molecular signatures provide new opportunities for utilizing biosensors. Biosensors have enormous potential to deliver the promise of new molecular diagnostic strategies to patients. This article describes some of the basic elements of cancer biology and cancer biomarkers relevant for the development of biosensors for cancer clinical testing, along with the challenges in using this approach.     

Comparison of Radioimmuno and Carbon Nanotube Field-Effect Transistor Assays for Measuring Insulin-Like Growth Factor-1 in a Preclinical Model of Human Breast Cancer

Background

To realize the promise of personalized medicine, diagnostic instruments used for detecting and measuring biomarkers must become smaller, faster and less expensive. Although most techniques used currently to detect biomarkers are sensitive and specific, many suffer from several disadvantages including their complexity, high cost and long turnaround time. One strategy to overcome these problems is to exploit carbon nanotube (CNT) based biosensors, which are sensitive, use inexpensive disposable components and can be easily adapted to current assay protocols. In this study we investigated the applicability of using a CNT field-effect transistor (CNT-FET) as a diagnostic instrument for measuring cancer biomarkers in serum using a mouse model of Breast Cancer Susceptibility 1-related breast cancer. Insulin like growth factor-1 (IGF-1) was chosen because it is highly relevant in breast cancer and because measuring serum IGF-1 levels by conventional methods is complicated due to specific IGF-1 serum binding proteins.

Findings

Our results show that there is good correlation between the two platforms with respect to detecting serum IGF-1. In fact, the CNT-FETs required only one antibody, gave real-time results and required approximately 100-fold less mouse serum than the radioimmunoassay.

Conclusions

Both IGF-1 radioimmuno and CNT-FET assays gave comparable results. Indeed, the CNT-FET assay was simpler and faster than the radioimmunoassay. Additionally, the low serum sample required by CNT-FETs can be especially advantageous for studies constricted by limited amount of human clinical samples and for mouse studies, since animals often need to be sacrificed to obtain enough serum for biomarker evaluation.