Advancements in the micro/nano-fabrication techniques have opened up new avenues for the development of portable and easier-to-use biosensors. Over the last few years, carbon electrodes have been widely used as sensing units in biosensors due to their attractive physiochemical properties. This book details different strategies to develop functionalized high surface carbon micro/nano-electrodes for electrochemical and biosensing devices. Carbon electrodes were fabricated via carbon-MEMS technique, which is based on pyrolyzing prepatterned photoresist. To increase the surface area of the carbon electrodes, multiple approaches such as (i) fabrication of porous 3D carbon microarrays, (ii) conformal coating of graphene onto 3D carbon microarrays, and (iii) fabrication of controllable carbon nanostructures were investigated. For carbon surface functionalization to covalently attach biomolecules, different oxidation techniques and the resultant surface carbon–oxygen groups were analyzed and compared. Lastly, label-free detection of platelet-derived growth factor oncoprotein, a cancer biomarker, was demonstrated on 3D carbon microarrays platform with sub-nanomolar detection limit.
Most books dedicated to the issues of bio-sensing are organized by the well-known scheme of a biosensor. In this book, the authors have deliberately decided to break away from the conventional way of treating biosensing research by uniquely addressing biomolecule immobilization methods on a solid surface, fluidics issues and biosensing-related transduction techniques, rather than focusing simply on the biosensor. The aim is to provide a contemporary snapshot of the biosensing landscape without neglecting the seminal references or products where needed, following the downscaling (from the micro- to the nanoscale) of biosensors and their respective best known applications. To conclude, a brief overview of the most popularized nanodevices applied to biology is given, before comparing biosensor criteria in terms of targeted applications.
BioMEMS (Biological Micro-Electro-Mechanical Systems) technology, especially for biosensors, plays a critical role in the process of information gathering with the technologically advanced development of our civilization. “Surface stress- based biosensors” are a relatively new class of biosensors, which make use of the free energy change, the underlying concept in any binding reaction, and hence offer a universal platform for biological or chemical sensing. In the book, a new surface stress-based polydimethylsiloxane (PDMS) micro membrane biosensor is proposed, designed, fabricated and tested. Each sensor consists of two micro membranes, one acts as active membrane and the other as reference. This design has sensitive surface stress measurements associated with specific analytes interactions on the active membrane''s surface.
Biosensor employing organelles in immobilized form are widely used in environmental monitoring. These immobilized organelles play vital role in sensitivity, accuracy, and stability of the biosensor system. Some of the organelle used for immobilization is whole cell, protein, enzyme and DNA. Traditionally biosensor used whole cell from one individual strain of microorganism. This concept limits the biosensor detection to certain specific samples alone. Detection of the content of the samples depends on the properties of the immobilized microbial cell. For detection of broad range of samples, novel biosenor using mixed microbial cultures is being designed in this dissertation.
Demand for biosensor research applications is growing steadily. According to a new report by Frost & Sullivan, the biosensor market is expected to reach $14.42 billion by 2016. Clinical diagnostic applications continue to be the largest market for biosensors, and this demand is likely to continue through 2016 and beyond. Biosensor technology for use in clinical diagnostics, however, requires translational research that moves bench science and theoretical knowledge toward marketable products. Despite the high volume of academic research to date, only a handful of biomedical devices have become viable commercial applications. Academic research must increase its focus on practical uses for biosensors. This book is an example of this increased focus, and discusses work to advance microfluidic-based protein biosensor technologies for practical use in clinical diagnostics.
Enzyme electrodes are biochemical transducers. They function by converting biochemical reactions into electrochemical processes. This functionality could potentially give rise to a new generation of implantable medical devices such as biofuel cells and biosensors. The main aim of this study was to fabricate and characterise enzyme electrodes for potential use in these applications. The approach involved testing various materials such as different types of enzyme, polymeric electron transfer mediators, enzyme entrapment materials, conductive supports and matrices and biocompatible polymers. Various enzyme immobilisation methods were used and various polymeric electron transfer mediators were fabricated and tested. The investigation was based primarily on electrochemical techniques. The materials and immobilisation techniques presented could potentially be used to improve future enzyme electrodes. This may be achieved through the novel use of biocompatible and biomimicking polymers, through simple biofuel cell fabrication and with the use of multi analyte biosensors developed during this investigation.
Biomedical electronics and instruments, equipment, diagnostic & detection tools success based on the success of high sensitive biosensors invention and development. Biosensors are the active electronic, semiconductor electronics, optoelectronics or other technologies related devices which sense biological signal from membrane in the form of antibodies, antigens, bacteria''s, viruses, glucose, oxygen, pH etc called signal/stimuli/receptor at the contact of membrane and biosensor with transducer along with biological sensing element called “ion-electron-interfacing” from where signal convert into detectable electrical signals through transduction principles and measured at computerized electronic signal processing system. This monograph strongly related only about optoelectronic biosensor, in which discussed investigated evanescent wave optical fiber biosensor is one of the strong light carry biological information sensation and high speed detection sensor. Book deal with review, research and fundamental modeling.
Biosensors are analytical devices for selective detection of an analyte or a group of analytes that combine biological material with a physicochemical detector, yielding a measurable signal. Biosensors are used in various fields of human activity, including environmental and clinical analyses, food analyses and control of industrial processes. Most efforts in biosensor studies have been focused on the fabrication of various combinations of biological components and measuring systems; less attention has been paid to the interpretation of factors, affecting the formation of biosensor output signal and the problems of biosensor calibration. So in many cases only a fraction of potentially available information is taken into consideration, making the biosensor analyses less reliable than they actually could be. The present work is an effort to solve some of the problems in biosensor signal analysis, proposing a new approach to signal modelling and calibration of biosensors, based on oxidoreductases; just to promote the application of these biosensors for on-line analyses.
Metallic starch capped gold nanoparticles have been synthesized by the reduction of chloroaurate anions [AuCl4]- solution with hydrazine in the aqueous starch and ethylene glycol solution at room temperature and at atmospheric pressure. The characterization of synthesized gold nanoparticles by UV–Vis spectroscopy, Scanning electron microscopy (SEM), X-ray diffraction (XRD) indicate that average size of pure gold NPs is 5-10 nm, they are spherical in shape and are pure metallic gold. Starch capped gold nanoparticles along with tyrosinase enzyme are effectively entrapped within sol-gel matrix for application in catechol biosensor. Enzymatic reaction between tyrosinase and catechol results in the formation of a colored compound which shows characteristic absorbance at 410 nm. Starch@AuNPs based catechol biosensor showed fast response with linearity for catechol sensing from 1 to 5 mM. Effect of buffer pH and its concentration was also studied and results showed drastic changes in absorption intensity with pH and concentration variation. Along with catechol biosensor, starch capped gold NPs find their application in glucose, urease and peroxide biosensor, owing to their stability.
This book aims towards the introduction of nanobiosensor technology and its extensive application in the biomedical detection of clinically important analytes such as; cancer cells, anticancer drugs, proteins etc. The fabrication of the biosensor system is described using various conducting polymers and nanomaterial composites. The content of the book also describes the step by step characterization of biosensor surface using various analytical techniques such as; x-ray photon spectroscopy, quartz crystal microbalance, scanning electron microscopy, transmission electron microscopy etc. The real sample applications of the biosensor has been explained in detail using various relevant examples. This book is an attempt to explain the graduate students to start up their experiments and also help them to conceptualize ideas and its representation.
Wire electrical discharge machining (WEDM) is used to manufacture conductive hard metal components with intricate shape, greater tolerance and precision. A review of the literature reveals that most of the research work has been directed towards the optimization of WEDM operation and modeling of the process. The present research work has been focused on the detailed study for the effect of cryogenic treatment to wire electrodes used in WEDM. Experimental setup has been developed to conduct the different set of experiments. The untreated and cryogenically treated brass wire electrodes have been tested for various properties, like micro-hardness, tensile strength, conductivity.It has been observed from experimental results that the wire grains are more refined in deep and shallow cryogenically treated wire electrodes. The electrical conductivity of deep and shallow cryogenically treated electrode has significantly improved. From the research work, it has been concluded that the deep and shallow cryogenically treated wire electrodes have enhanced the MRR, improved the surface finish and WWR significantly.
A new micro-fluidic biosensor array for fast online adherent cell monolayer analysis during cell proliferation and stimulation was developed. Quartz crystal resonators and impedimetric sensor responses were analysed by means of impedance spectroscopy. Time-lapse light microscopy was employed for visual characterization of the cells. Four independent units embedded within the same device allow parallelized cell cultivation. An external flow injection system provides automated and parallelized media feed as well as overpressure regime in the system. Thin-film deposition techniques were applied for sensors fabrication. New dedicated sensor interface electronics were developed to allow fast and parallelized spectra acquisition on 32 sensors. Madin-Darby Canine Kidney cells were cultivated in the biosensor array. The cell behavior during cell proliferation and stimulation was analyzed online. It is believed that in the future, the new biosensor array can be successfully employed as a tool supporting standard techniques employed in molecular cell biology for the study of that complex system of communication that governs basic cellular activities and coordinates cell actions.
This monograph presents results of investigations on fields and multipole expansion coefficients in axially symmetric (referred to as 3D) and two dimensional (2D) ion trap mass analysers. 3D mass analysers have a three-electrode geometry with two (electrically shorted) endcap electrodes and one central ring electrode. rf-only or rf/dc potential applied across the electrodes creates a linear trapping field in the central cavity of the mass analyser. 2D mass analysers have four longitudinal electrodes in which the opposite pairs of electrodes are electrically shorted. Here, rf-only or rf/dc potential applied across the pair of electrodes creates a linear trapping field and fragment ions of the analyte gas are trapped along the central axis of the mass analyser. Both these mass analysers have apertures machined on the electrodes (holes in case of 3D traps and slits in case of 2D traps) to permit entry of electrons for ionising the analyte gas and for collection of destabilized fragment ions. This thesis is concerned with how these apertures influence the fields and multipole expansion coefficients within the traps. This thesis is divided into five chapters.