Bioelectronics with graphene nanostructures

Biophysics Reviews, 2021

The ability to manipulate the electrophysiology of electrically active cells and tissues has enabled a deeper understanding of healthy and diseased tissue states. This has primarily been achieved via input/output (I/O) bioelectronics that interface engineered materials with biological entities. Stable long-term application of conventional I/O bioelectronics advance as materials and processing techniques develop. Recent advancements have facilitated the development of graphene-based I/O bioelectronics with a wide variety of functional characteristics. Engineering the structural, physical, and chemical properties of graphene nanostructures and integration with modern microelectronics have enabled breakthrough high-density electrophysiological investigations. Here, we review recent advancements in 2D and 3D graphene-based I/O bioelectronics and highlight electrophysiological studies facilitated by these emerging platforms. Challenges and present potential breakthroughs that can be addressed via graphene bioelectronics are discussed. We emphasize the need for a multidisciplinary approach across material science, micro-fabrication, and bioengineering to develop the next generation of I/O bioelectronics.

Frontiers of Materials Science, 2018

Graphene is a fascinating material of recent origin whose first isolation was being made possible through micromechanical cleavage of a graphite crystal. Owing to its fascinating properties, graphene has garnered significant attention in the research community for multiple applications. A number of methods have been employed for the synthesis of single-layer and multi-layer graphene. The extraordinary properties of graphene such as its Hall effect at room temperature, high surface area, tunable bandgap, high charge mobility and excellent electrical, conducting and thermal properties allow for the development of sensors of various types and also opened the doors for its use in nanoelectronics, supercapacitors and batteries. Biological aspects of graphene have also been investigated with particular emphasis on its toxicity and drug delivery. In this review, many of the salient aspects of graphene, such as from synthesis to its applications, primarily focusing on sensor applications which are of current interest, are covered.

Sensors and Materials, 2018

Graphene possesses a high surface-to-volume ratio, which enables biomolecules to attach to it for bioelectronic applications. In this article, first, the classification and applications of bioelectronic devices are briefly reviewed. Then, recent work on real fabricated graphenebased bioelectronic devices as well as the analysis of their architecture and design using a computational approach to their charge transport properties are presented and discussed. A comparison to nongraphitic bioelectronic devices is also given. On the macroscale level, the design of devices is elaborated on the basis of a finite element analysis (FEA) approach, and the impact of design on the performance of the devices is discussed. On the nanoscale level, transport phenomena and their mechanisms for different design categories are elaborated on the basis of the density functional theory (DFT) and other quantum chemistry calculations. The calculated and measured charge transport properties of graphene-based bioelectronic devices are also compared with those of other available bioelectronic devices.

Sensors

The advantages conferred by the physical, optical and electrochemical properties of graphene-based nanomaterials have contributed to the current variety of ultrasensitive and selective biosensor devices. In this review, we present the points of view on the intrinsic properties of graphene and its surface engineering concerned with the transduction mechanisms in biosensing applications. We explain practical synthesis techniques along with prospective properties of the graphene-based materials, which include the pristine graphene and functionalized graphene (i.e., graphene oxide (GO), reduced graphene oxide (RGO) and graphene quantum dot (GQD). The biosensing mechanisms based on the utilization of the charge interactions with biomolecules and/or nanoparticle interactions and sensing platforms are also discussed, and the importance of surface functionalization in recent up-to-date biosensors for biological and medical applications.

Materials Today, 2013

Graphene, a single layer 2-dimensional structure nanomaterial with unique physicochemical properties (e.g. high surface area, excellent electrical conductivity, strong mechanical strength, unparalleled thermal conductivity, remarkable biocompatibility and ease of functionalization), has received increasing attention in physical, chemical and biomedical fields. This article selectively reviews current advances of graphene based materials for biomedical applications. In particular, graphene based biosensors for small biomolecules (glucose, dopamine etc.), proteins and DNA detection have been summarized; graphene based bioimaging, drug delivery, and photothermal therapy applications have been described in detail. Future perspectives and possible challenges in this rapidly developing area are also discussed.

Advanced Drug Delivery Reviews, 2011

Graphene's unique properties have made it a popular candidate for nanomaterial based biosensors. Its remarkable characteristics have led to its rapid development in the electrochemical biosensing, field effect transistors, and optical biosensing as well as the creation graphene-metal nanoparticle hybrids for improved performance. This article comprehensively reviews the most recent trends in graphene-based biosensors and attempts to identify the future directions in which the field is likely to thrive.

Diagnostics

Since the discovery of the two-dimensional (2D) carbon material, graphene, just over a decade ago, the development of graphene-based field effect transistors (G-FETs) has become a widely researched area, particularly for use in point-of-care biomedical applications. G-FETs are particularly attractive as next generation bioelectronics due to their mass-scalability and low cost of the technology’s manufacture. Furthermore, G-FETs offer the potential to complete label-free, rapid, and highly sensitive analysis coupled with a high sample throughput. These properties, coupled with the potential for integration into portable instrumentation, contribute to G-FETs’ suitability for point-of-care diagnostics. This review focuses on elucidating the recent developments in the field of G-FET sensors that act on a bioaffinity basis, whereby a binding event between a bioreceptor and the target analyte is transduced into an electrical signal at the G-FET surface. Recognizing and quantifying these t...

Nano Letters, 2013

Semiconducting nanomaterials are being intensively studied as active elements in bioelectronic devices, with the aim of improving spatial resolution. Yet, the consequences of size-reduction on fundamental noise limits, or minimum resolvable signals, and their impact on device design considerations have not been defined. Here, we address these key issues by quantifying the size-dependent performance and limiting factors of graphene (Gra) transducers under physiological conditions. We show that suspended Gra devices represent the optimal configuration for cardiac extracellular electrophysiology in terms of both transducer sensitivity, systematically ∼5× higher than substrate-supported devices, and forming tight bioelectronic interfaces. Significantly, noise measurements on freestanding Gra together with theoretical calculations yield a direct relationship between low-frequency 1/f noise and water dipole-induced disorders, which sets fundamental sensitivity limits for Gra devices in physiological media. As a consequence, a square-root-of-area scaling of Gra transducer sensitivity was experimentally revealed to provide a critical design rule for their implementation in bioelectronics.

Journal of Nanobiotechnology

Diverse properties of graphenic materials have been extensively explored to determine properties that make good electrochemical nanomaterial-based biosensors. These are reviewed by critically examining the influence of graphene nano-morphology, lattice defects and conductivity. Stability, reproducibility and fabrication are discussed together with sensitivity and selectivity. We provide an outlook on future directions for building efficient electrochemical biosensors.

Functional Composites and Structures

The worldwide frontiers of research have experienced a flood of developments in advanced nanomaterials. Among these, graphene, a member of the carbon family, has now replaced many traditional materials and broadened the horizons of material chemistry, analytical chemistry, pharmaceutics, and other multidisciplinary fields. Owing to the exceptional properties of graphene, it has been widely utilized in various nanocomposites as a reinforcing material and for biosensing components. The present review serves as a familiarization for budding researchers in the materials science and analytical fields, where the use of graphene in biosensing-related applications had long been foreseen. Furthermore, we also offer a brief review of graphene's tunable properties for biosensing. This article describes the actual mechanisms of interfaces that interact with graphene, such as immunogenic agents, bacteria, and other biomolecules. We also discuss the application of graphene-based materials to the biosensing of a range of analytes, and the challenges and future perspectives of graphene. Thus, this review gives a detailed insight into biosensing with graphene, graphene's fundamental properties, and application perspectives.