A Review on Biosensors and Recent Development of Nanostructured Materials-Enabled Biosensors

Abstract

A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal. The design and development of biosensors have taken a center stage for researchers or scientists in the recent decade owing to the wide range of biosensor applications, such as health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery. The main challenges involved in the biosensor progress are (i) the efficient capturing of biorecognition signals and the transformation of these signals into electrochemical, electrical, optical, gravimetric, or acoustic signals (transduction process), (ii) enhancing transducer performance i.e., increasing sensitivity, shorter response time, reproducibility, and low detection limits even to detect individual molecules, and (iii) miniaturization of the biosensing devices using micro-and nano-fabrication technologies. Those challenges can be met through the integration of sensing technology with nanomaterials, which range from zero- to three-dimensional, possessing a high surface-to-volume ratio, good conductivities, shock-bearing abilities, and color tunability. Nanomaterials (NMs) employed in the fabrication and nanobiosensors include nanoparticles (NPs) (high stability and high carrier capacity), nanowires (NWs) and nanorods (NRs) (capable of high detection sensitivity), carbon nanotubes (CNTs) (large surface area, high electrical and thermal conductivity), and quantum dots (QDs) (color tunability). Furthermore, these nanomaterials can themselves act as transduction elements. This review summarizes the evolution of biosensors, the types of biosensors based on their receptors, transducers, and modern approaches employed in biosensors using nanomaterials such as NPs (e.g., noble metal NPs and metal oxide NPs), NWs, NRs, CNTs, QDs, and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

Keywords: biosensors; carbon nanotubes; gold nanoparticles; nanobiosensing; nanomaterials; quantum dots.

Figure 1

Classification of sensors based on measurand, energy/power, physical contact, signal conversion, output signal, comparability, sensor material, specification, and applications (reproduced from White et al. Ref. [6]).

Figure 2

Schematic diagram of typical biosensor consisting of bioreceptor, transducer, electronic system (amplifier and processor), and display (PC or printer) and various types of bioreceptors and transducers used in the biosensors are also shown.

Figure 3

Three generations of the biosensor construction (M_OX: Oxidized mediator; M_Red: Reduced mediator).

Figure 4

Classification of biosensors based on various bioreceptors and transducers used.

Figure 5

Enzyme immobilization techniques.

Figure 6

Schematic diagram of (a) amperometric/voltammetric, (b) potentiometric, (c) conductometric biosensors, and (d) equivalent circuit of the impedimetric biosensor (C_dl = double-layer capacitance of the electrodes, R_sol = resistance of the solution, C_de = capacitance of the electrode, Z_cell = impedance introduced by the bound nanoparticles, and R_cell and C_cell are the resistance and capacitance in parallel).

Figure 7

Schematic diagrams of (a) chemiluminescence biosensor, (b) surface plasmon resonance (SPR) biosensor, and (c) evanescent wave-based optical fiber biosensor.

Figure 8

Schematic diagrams of (a) piezoelectric-based biosensor, (b) quartz crystal microbalance-based biosensor, and (c) magnetoelastic-based biosensor.

Figure 9

Schematic diagrams of (a) enzyme thermistor-based biosensor, (b) Si nanowire-based field-effect transistor (FET) (D is drain and S is the source) biosensor, and (c) surface acoustic wave (SAW)-based biosensor.

Figure 10

Classification of nanomaterials according to their dimensionality.

Figure 11

Types of nanomaterials-based biosensors (nanobiosensors).