Silicon-Based Sensors for Biomedical Applications: A Review

Abstract

The paper highlights some of the significant works done in the field of medical and biomedical sensing using silicon-based technology. The use of silicon sensors is one of the pivotal and prolonged techniques employed in a range of healthcare, industrial and environmental applications by virtue of its distinct advantages over other counterparts in Microelectromechanical systems (MEMS) technology. Among them, the sensors for biomedical applications are one of the most significant ones, which not only assist in improving the quality of human life but also help in the field of microfabrication by imparting knowledge about how to develop enhanced multifunctional sensing prototypes. The paper emphasises the use of silicon, in different forms, to fabricate electrodes and substrates for the sensors that are to be used for biomedical sensing. The electrical conductivity and the mechanical flexibility of silicon vary to a large extent depending on its use in developing prototypes. The article also explains some of the bottlenecks that need to be dealt with in the current scenario, along with some possible remedies. Finally, a brief market survey is given to estimate a probable increase in the usage of silicon in developing a variety of biomedical prototypes in the upcoming years.

Keywords: biomedical; nanowire; semiconducting; sensors; silicon.

Figure 1

The insertion of wireless pressure sensors into the animal was done (a) at three different places (b) to perform the biocompatibility test and determine the blood pressure [69]. The image has been reproduced with permission from [69].

Figure 2

(a) Schematic diagram of the nanoscaled-FET silicon-based sensors. (b) Binding of the target molecules with the receptors. (c) Surface modification of the FET device done with a π-π interaction process, immobilisation and detection. (d) Release of the neurons on the sensing surface of the FETs to determine the change in current with respect to the time [81]. The image has been reproduced with permission from [81].

Figure 3

The schematic representation of the skein SiNW incorporated FET fabrication process. [82]. The image has been reproduced with permission from [82].

Figure 4

Schematic diagram to represent the interfacing of Bioresorbable sensors with the communication modules for the wireless data transfer. The image also shows the connection of the bioresorbable pressure and temperature sensors integrated with the dissolvable metal interconnect [92]. The image has been reproduced with permission from [92].

Figure 5

Schematic diagram of the fabrication process of the bioresorbable pressure sensors. The sensors were developed with monocrystalline silicon and silicon dioxide layers using thermal oxidation and electron-beam techniques. Two boundary lines were used to separate the strain gauges from the surrounding silicon. The system consisted of piezoresistive sensors, a voltage source and a meter to compensate for the variation of the temperature caused by the variation in the resistance with the pressure [95]. The image has been reproduced with permission from [95].