**Acknowledgements**

This work received financial support from the Foundation for Research of the State of Rio Grande do Sul (FAPERGS – Project 19/2551-0001362-0), so all thanks.

**157**

Brazil

**Author details**

William Leonardo da Silva\*, Daniel Moro Druzian, Leandro Rodrigues Oviedo,

Nanoscience Graduate Program – Universidade Franciscana, Santa Maria - RS,

© 2021 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,

Pâmela Cristine Ladwig Muraro and Vinícius Rodrigues Oviedo

\*Address all correspondence to: w.silva@ufn.edu.br

provided the original work is properly cited.

*Silver Nanoparticles for Photocatalysis and Biomedical Applications*

*DOI: http://dx.doi.org/10.5772/intechopen.95922*

## **Conflict of interest**

The authors declare no competing interests.

*Silver Nanoparticles for Photocatalysis and Biomedical Applications DOI: http://dx.doi.org/10.5772/intechopen.95922*

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*

biosensor [107]. LSPR-based ones are established on changes in the occurring refractive index now that photons are directed to the nanoparticles, leading them to oscillation [108], being used in biomolecules detection [109]. It is also important to mention that AgNPs are normally functionalized before applying them as biosensors to overcome chemical stability and toxicity aspects [110]. Therefore, coating AgNPs with organic or inorganic materials are the common approaches. Furthermore, polymeric coatings are also used to functionalize AgNPs by using either synthetic polymers, such as (poly)-ethylene glycol (PEG) [111], (poly)-vinyl alcohol (PVA) [112] and (Poly)-vinylpyrrolidone (PVP) [113], or natural polymers such as starch [114], sodium alginate [115] and chitosan [116]. Functionalization with polymeric blends that uses both synthetic and natural polymers is also an interesting approach (e.g. PVA/Chitosan-coated AgNPs [117]). The inorganic coating involves the functionalization of AgNPs with silicon dioxide [118], while organic coating involves citrates mainly [119]. Furthermore, there are plenty of electrochemical-based AgNPs biosensors [120, 121], however, they will not be covered here as the focus is on the plasmonic ones. Another possible application of AgNPs is the surface enhanced Raman Spectroscopy (SERS), which involves the adsorption of molecules on the AgNPs to achieve a high-quality spectroscopy technique. The applications of SERS focus on disease diagnosis caused by microbial infections or cancer [122].

Therefore, AgNPs-based biosensors are good alternatives against conventional sensing devices, as nanostructured biosensors show greater sensibility, reliability, wide limits of detection, precision, speed and provides eye-naked colorimetric assays together with quantitative analysis [123], among other unique characteristics

Regarding the use AgNPs in heterogeneous photocatalysis, it can be proved highly efficient in the degradation a large amount of organic pollutants and inactivation of bacteria and pathogens, under either UV radiation or visible light. Moreover, when supported AgNPs-based nanophotocatalysts are used in wastewater not only the photocatalytic activity is enhanced, but also some operational problems (nanoparticles agglomeration) can be fixed. With respect to the use of AgNPs as antimicrobial agents, it is a current alternative against common pathogens and multi-resistant bacteria due to the toxicity to microorganisms compared to antibiotics and conventional approaches. In addition, AgNPs-based biosensors are resulting in high sensitivity and selectivity aligned to wide detection limits, which turns them suitable for clinical practice. It is worth to point out that the green synthesis of AgNPs is increasing along the years, and when combined with photocatalytic and biomedical applications,

contributes to sustainable development and biocompatibility aspects.

This work received financial support from the Foundation for Research of the State of Rio Grande do Sul (FAPERGS – Project 19/2551-0001362-0), so all thanks.

that are shown in the papers summarized in **Table 3.**

**4. Conclusion**

**Acknowledgements**

**Conflict of interest**

The authors declare no competing interests.

**156**
