**Author details**

Baiju John1,2,3

*Nanorods and Nanocomposites*

ing (detection limit ~1.1 fg mL<sup>−</sup><sup>1</sup>

a reported detection limit of 104 ng mL<sup>−</sup><sup>1</sup>

orientation with a detection capacity of 10 ng mL<sup>−</sup><sup>1</sup>

analyzed through electrode response of [Fe(CN)6]

like military, health-care and community fitness initiatives.

I-AuNP-PEDOT-modified Pt electrode electrochemical immunosensor helped in the detection of alpha-fetoprotein (AFP) through electrochemiluminescence (ECL) sens-

immobilize the antibody, the nanoAu-PEDOT facilitated the electron transfer, and Azure I did the catalytic reduction of redox dye with two active amino groups [36]. PANI-AuNP-modified paper working electrodes (PANI-AuNP PWEs) were fabricated for the simultaneous determination of two tumor markers, carcinoembryonic antigen (CEA) and AFP, in real human serum samples [37]. An electrochemical immunosensor for prolactin hormone was also constructed by immobilizing the antigen onto poly (pyrrolepropionic acid) CP and carbon nanotube (pPPA/CNT) hybrids deposited onto a GCE and labeled with AP enzyme with

used to manufacture a bioelectrode for the detection of human C-reactive protein antigen (Ag-αCRP). This was made possible with the inorganic nanoparticles (3-mercaptopropionic acid (MPA)-capped Pt nanoparticles. First, the Ab-αCRP was immobilized covalently through specific carboxyl groups linkages through Pt(MPA)- NPs within the polypyrrole (PPy)-based PNC film by carbodiimide coupling. The resulted electrochemical immunosensor showed excellent fine probe

label-free impedimetric immunosensor based on multifunctional PNCs was based on (polypyrrole–pyrrolepropylic acid–reduced graphene oxide (PPy-PPa-rGO)) for the detection of mycotoxin aflatoxin B1 [40]. An enzyme-free electrochemical immunosensor modeled on the *sandwich* pattern was used for the detection of carbohydrate antigen 72–4 (CA72–4). The sensing electrode was nanoporous gold (NPG) film and asymmetric multicomponent (AMNPs) nanoparticles based on PANI-Au was used as labels. The NPG helped in the creased immobilization of Ab1 on the electrode, while the PANI-Au AMNPs impacted on the reduction capability of the electrochemical immunosensor [41]. The doping of AuNPs and PANI films with potassium ferricyanide over a gold electrode was used to detect a carcinoembryonic antigen (CEA). This PNC-based biocompatible electrochemical immunosensor showed excellent conductivity and redox electroactivity. The detection of CEA was

PNCs have been explored for the construction of novel biosensors using PNC like materials as sensing elements. The efficient combination of different nanoscaled materials with good conductive polymers open a new avenue for utilizing novel PNCs as enhanced elements for constructing electrochemical sensing platforms with high performance. Health monitoring wearable tech like Fitbit or Apple Watch are all based on the PNC electrochemical sensors are of great interest in the health industry for the detection of physiological parameters of the human body. The progress of PNC-based wearable electrochemical sensors to analyses biochemical fluids other than blood such as interstitial fluids, sweat, tears, and saliva invoked interests in Silicon Valley echelons like Google, OrSense, and NovioSense which made the sector more interesting. Another significant challenge is the technical challenges to the wearability of the PNC-based material for manufacturing the same which includes analytical performance and biocompatibility. There is significant progress reported on the PANI-based wearable immunosensor used for epidermal pH monitoring. With all these advances the future of PNC-based devices is promising and applications shall reach out to commercial sensing applications

). The sensing mechanism was as follows: ZnSe QDs

[38]. Polypyrrole (PPy)-based PNC was

[39]. Another

<sup>3</sup><sup>−</sup> as the redox mediator [42].

–10 μg mL<sup>−</sup><sup>1</sup>

**166**

**5. Conclusion**

1 Advanced Polymeric Nanostructured Materials Engineering, Graduate School of Engineering, Toyota Technological Institute, Nagoya, Japan

2 The Center for Biomedical Engineering, UTMB Galveston, Galveston, Texas, USA

3 Duann Innovations and Systems, Houston, TX, USA

\*Address all correspondence to: jonsbaiju@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
