Nanomaterials for Healthcare Biosensing Applications

In recent years, an increasing number of nanomaterials have been explored for their applications in biomedical diagnostics, making their applications in healthcare biosensing a rapidly evolving field. Nanomaterials introduce versatility to the sensing platforms and may even allow mobility between different detection mechanisms. The prospect of a combination of different nanomaterials allows an exploitation of their synergistic additive and novel properties for sensor development. This paper covers more than 290 research works since 2015, elaborating the diverse roles played by various nanomaterials in the biosensing field. Hence, we provide a comprehensive review of the healthcare sensing applications of nanomaterials, covering carbon allotrope-based, inorganic, and organic nanomaterials. These sensing systems are able to detect a wide variety of clinically relevant molecules, like nucleic acids, viruses, bacteria, cancer antigens, pharmaceuticals and narcotic drugs, toxins, contaminants, as well as entire cells in various sensing media, ranging from buffers to more complex environments such as urine, blood or sputum. Thus, the latest advancements reviewed in this paper hold tremendous potential for the application of nanomaterials in the early screening of diseases and point-of-care testing

SWCNT-Based Biosensor Modelling for pH Detection

Different forms of CNT delivery have been discovered with several biomedical functions during past decades. The mechanisms of the cellular uptake of CNTs are mainly maintained due to the chemical nature, the cell type, and the features of the molecules, which are used to functionalize the nanotube exterior. Since single-wall carbon Nanotube (SWCNT) has unique chemical and physical properties, it is a great applicant for pH sensing. In addition, ion sensitive FET (ISFET) base on nanostructured SWCNT have covered a new method to help genetic investigators restructure metabolic pathways in cells, recognize the progression of disease, and expand diagnostics and therapeutics. Particularly, because PH sensing is very crucial for the constancy of enzymes, it is essential to extend the cost efficient types of this sensing. In this research, the conductance changes of the CNT-based ISFET device with different pH values can be modelled by ion concentration of the solution. In addition, the electrical current of channel is imagined as a function of pH levels, which can be controlled by a control factor (α). Thus, ISFET based nanostructured SWCNT is proposed focusing on the area of electrical detection of hydrogen ions of the electrolyte membrane. Besides, electrical detection of hydrogen ion applications is suggested to be used by modelling the delivery of SWCNT sheets. In the end, after comparing the proposed model and experimental data, it has been reported that there is a good compatibility between them

Biosensors

A biosensor is defined as a detecting device that combines a transducer with a biologically sensitive and selective component. When a specific target molecule interacts with the biological component, a signal is produced, at transducer level, proportional to the concentration of the substance. Therefore biosensors can measure compounds present in the environment, chemical processes, food and human body at low cost if compared with traditional analytical techniques. This book covers a wide range of aspects and issues related to biosensor technology, bringing together researchers from 11 different countries. The book consists of 16 chapters written by 53 authors. The first four chapters describe several aspects of nanotechnology applied to biosensors. The subsequent section, including three chapters, is devoted to biosensor applications in the fields of drug discovery, diagnostics and bacteria detection. The principles behind optical biosensors and some of their application are discussed in chapters from 8 to 11. The last five chapters treat of microelectronics, interfacing circuits, signal transmission, biotelemetry and algorithms applied to biosensing

High-power biofuel cells based on threedimensional reduced graphene oxide/ carbon nanotube micro-arrays

Miniaturized enzymatic biofuel cells (EBFCs) with high cell performance are promising candidates for powering next-generation implantable medical devices. Here, we report a closed-loop theoretical and experimental study on a micro EBFC system based on three-dimensional (3D) carbon micropillar arrays coated with reduced graphene oxide (rGO), carbon nanotubes (CNTs), and a biocatalyst composite. The fabrication process of this system combines the top–down carbon microelectromechanical systems (C-MEMS) technique to fabricate the 3D micropillar array platform and bottom–up electrophoretic deposition (EPD) to deposit the reduced rGO/CNTs/enzyme onto the electrode surface. The Michaelis–Menten constant KM of 2.1 mM for glucose oxidase (GOx) on the rGO/CNTs/GOx bioanode was obtained, which is close to the KM for free GOx. Theoretical modelling of the rGO/CNT-based EBFC system via finite element analysis was conducted to predict the cell performance and efficiency. The experimental results from the developed rGO/CNT-based EBFC showed a maximum power density of 196.04 µW cm−2 at 0.61 V, which is approximately twice the maximum power density obtained from the rGO-based EBFC. The experimental power density is noted to be 71.1% of the theoretical value

NANOELECTRONIC DEVICES FOR SENSITIVE DETECTION OF BIOMARKERS IN HEALTHCARE MONITORING

In recent years, biosensors have seen an exponential rise of their applications in a number of fields including the field of health care monitoring, particularly in point-of-care diagnostics. With the contemporary rise of nanotechnology, these biosensors have experienced an ever-growing inclusion of nano scale electronic devices or nanoelectronic devices to exploit the plethora of advantages of nanoelectronics. The performances of these nanoelectronic devices, however, largely depend on the nanomaterials used. Especially, carbon-based nanomaterials such as carbon nanotubes (CNTs) and graphene have proven to be superior candidates compared to others because of their multitude of electronic and mechanical properties suitable for biosensing. In particular, graphene-based FET (GFET) that combines the favorable material properties of graphene as well as the device properties of field-effect transistor have demonstrated its potential in biosensing with high sensitivity and signal-to-noise ratio (SNR). Though GFETs have been applied for sensitive detection of a number of analytes, there are still areas for further development in a number of ways—application of the platform for sensing new biomarkers, developing an integrated microfluidics platform, etc. in order to improve the sensing performances as well as applicability in real-world setting. Therefore, in this seminar, I will discuss the current states and challenges of the GFET-based sensing and present my work to further advance this platform. Moreover, development of a flexible GFET biosensor compatible with wearable platform will also be discussed. To provide the biosensors with the required selectivity, DNA-based aptamers with specific affinity towards the target analyte are used. However, conventional techniques for functionalization of aptamers suffer from several challenges including low throughput, poor control, and long turnaround time. To address these challenges, I will present my efforts on the development of new strategies to address these challenges both on CNT and graphene-based platforms

Randomized Network of Single Walled Carbon Nanotubes Thin Film Transistor: Fabrication, Simulation and Application as Biosensor

2011 - 2012Nanoelectronic devices based on nanomaterials, such as carbon nanotubes (CNTs) have attracted remarkable attention as a promising building block for future nanoelectronic circuits due to their exceptional electrical, mechanical and chemical characteristics. The electrical characteristics of CNTs, such as high mobility, quasiballistic conductance and resistance against electromigration, allow to surpass the properties of current Si based complementary metal oxide semiconductor (CMOS) devices. In particular, the large surface area and nanoscale structure makes SWCNTs promising candidates for chemical and biological sensing applications as well. Current research covers broad scientific fields, such as study of materials properties at nanoscale, development, fabrication and simulation of nanoscale structures, for electronics and biomedical applications. However, there is ample space for advancements in both theoretical studies and practical applications for CNT-based systems. This thesis addresses the design and manufacture of thin film transistor (TFT) based on randomized network of single walled carbon nanotubes (SWCNTs) that exploit the unique properties of such materials to create a label-free biosensor for detection of variety biomolecules, particularly proteins. In addition, in order to analyze the electric transport of SWCNTs network in the TFT channel a numerical 3-dimensional (3D) model for the thin film layer is developed. The SWCNTs-TFTs are fabricated by using microfabrication to obtain a micro-interdigitated electrode (μ-IDE) as drain-source electrode. The sizes vary between 2 to 50 μm. Thin-film transistors (TFTs) are fabricated by using SWCNTs thin film as the semiconducting layer and SiO2 thin film as the dielectric layer. The high purity semiconducting network of SWCNTs layer is deposited with an effective technique that combines the silanization of the substrate with vacuum filtration process from dispersed SWCNTs in surfactant solution. . The adopted technique provides a low-cost, fast, simple, and versatile approach to fabricate high-performance SWCNTs-TFTs at room temperature. The morphological arrangement of SWCNTs forming the active layer in the channel of the transistor is checked with scanning electron microscopic (SEM). The TFTs obtained exhibit p-type transistor characteristics and operate in 2 accumulation mode. The results are interpreted by considering the percolation theory. The exponent a of the power law describing the conductivity can be linked to the structural complexity of the SWCNT network. In particular an exponent = 1.7 was found experimentally, showing that the obtained thin film is relatively dense and near percolation. In addition, the experimental data have been compared with the results of the 3D model simulating the charge transport in the SWCNT structures formed in the TFT channel. The simulation results lead to an exponent = 1.8 that is in good agreement with the experimental data. The proposed model seems to be able to reliably reproduce the transport characteristics of the fabricated devices and could be an effective tool to improve the SWCNTs-TFTs structure. Moreover, the fabricated SWCNTs-TFT devices provide a suitable platform for high-performance biosensors in label-free protein detection. The sensing mechanism is demonstrated on a proof of principle level for the interaction of biotin and streptavidin on the SWCNTs surface. It is used as a research model for biosensor application. The SWCNTs thin-film biosensor has high sensitivity and it is capable of detecting streptavidin at concentration of 100 pM. [edited by author]XI n.s

A nonlocal sinusoidal plate model for micro/nanoscale plates

A nonlocal sinusoidal plate model for micro/nanoscale plates is developed based on Eringen’s nonlocal elasticity theory and sinusoidal shear deformation plate theory. The small scale effect is considered in the former theory while the transverse shear deformation effect is included in the latter theory. The proposed model accounts for sinusoidal variations of transverse shear strains through the thickness of the plate, and satisfies the stress-free boundary conditions on the plate surfaces, thus a shear correction factor is not required. Equations of motion and boundary conditions are derived from Hamilton’s principle. Analytical solutions for bending, buckling, and vibration of simply supported plates are presented, and the obtained results are compared with the existing solutions. The effects of small scale and shear deformation on the responses of the micro/nanoscale plates are investigated