with elasticity and responsiveness are employed in a range of applications [39].

Biosensors based on field-effect transistors (FETs) are found useful for detecting bio­

molecules. Silicon nanowires, carbon nanotubes, and graphene are examples of inorganic

materials which could be used in FET substrates owing to their high surface-to-volume

ratios and comparable electrical potentials of the surface and bulk [40]. One of the major

challenges when using nanocomposites for FET-based biosensors is obtaining the re­

quisite conformity and reproducibility. Rim et al [13]. devised a simple solution treatment

approach for fabricating ultrathin, selective Indium (III) oxide (In2O3) semiconducting

FETs with outstanding device performance and minimal mechanical stress for biological

sensing applications. Two-dimensional transition metals dichalcogenides (TMDs) have

attracted interest in biosensors with intriguing properties, such as a changeable bandgap

and a fast heterogeneous electron-transfer (HET) rate. These materials are, under­

standably, very appealing in the realm of biosensors [41].

In bioelectronics, two-dimensional ultrathin materials with softness and adaptability,

like graphene, can be used. Because the graphene-based soft neural implantation has such

a good elasticity, it can mitigate mechanical injury to neural cells while developing

precise integration with the brain [42].

12.4.2 Wearable and Implantable Devices

As described in the preceding sections, electronics that may be worn or implanted have

made significant advances in biomedical applications [1,13]. Some of these technologies

are being integrated into our modern routines through gadgets such as smartwatches,

bracelets, and protective clothing. In the 1960s, the first implanted cardiac pacemaker for

arrhythmia patients was invented. Nevertheless, millions of patients were treated with

improved pacemakers, implanted cardioverter defibrillators (ICDs), and implantable

deep brain stimulators [43]. Because of the morphological disparity between those brittle,

massive implanted equipment and tender muscle tissue, inadequate electrical and phy­

sicochemical operations, as well as severe immunological reactions, limited their utility

for extended practical purposes [10,44]. To achieve these goals, several soft-material

bioelectronic devices have been proposed. Paper-thin pliable 2D composites have indeed

been recognized among the materials available [20,45].

Inorganic semiconductors are a preferred option for flexible electronics because of their

homogeneity, stability, exceptional electrical characteristics, and scalable manufacturing

[46]. Another area of interest is to utilize the biomechanical energy of our body for self-

powered wearable devices. It needs only a few electrodes that can convert the bio­

mechanical energy during body moving (Figure 12.5). This technique is very simple and

effective to produce biomechanical energy during the walk or exercise, which has great

possibilities for being functional to self-energy wearable and implantable electronics in

the forthcoming days [47].

Inorganic semiconductors could be integrated on soft and fine surfaces because of

breakthroughs in transfer-printing and minimal temperature techniques, allowing

structural fit between electronics and biological tissues. Initially, silicon proved to be a

promising candidate for several wearable and implantable electronics, owing to their

relatively minimal cost, ease of access, and conventional processing technologies [20].

Flexible silicon devices include soft wireless transmission systems based on crystalline

silicons on polymeric materials with high transport mobilities [48], as well as cardiac

electrophysiology recording devices [49]. The indirect bandgap, poor piezoelectric coef­

ficients, rapid ionic dispersion, and biofluid disintegration of silicon, however, limit its

Semiconducting Nanostructured Materials

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