Potentialities of bioinspired metal and metal oxide nanoparticles in biomedical sciences

Abstract

To date, various reports have shown that metallic gold bhasma at the nanoscale form was used as medicine as early as 2500 B.C. in India, China, and Egypt. Owing to their unique physicochemical, biological, and electronic properties, they have broad utilities in energy, environment, agriculture and more recently, the biomedical field. The biomedical domain has been used in drug delivery, imaging, diagnostics, therapeutics, and biosensing applications. In this review, we will discuss and highlight the increasing control over metal and metal oxide nanoparticle structures as smart nanomaterials utilized in the biomedical domain to advance the role of biosynthesized nanoparticles for improving human health through wide applications in the targeted drug delivery, controlled release drug delivery, wound dressing, tissue scaffolding, and medical implants. In addition, we have discussed concerns related to the role of these types of nanoparticles as an anti-viral agent by majorly highlighting the ways to combat the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic, along with their prospects.

Fig. 1. An illustration of nanoparticle synthesis via different biological/green, chemical, and physical methods, along with top-down and bottom-up.

Fig. 2. A schematic illustration showing the positive aspects of green synthesis techniques over chemical and physical routes.

Fig. 3. An illustration of the laboratory-based method to synthesize various metal and metal oxide nanoparticles using plant extracts, algae, fungi, bacteria, and natural extracts, along with the metal salt, which results in the production of the desired metal and metal oxide nanoparticles. Various applications of these biosynthesized metal and metal oxide nanoparticles are also shown in the figure.

Fig. 4. Schematic representation of the biomedical utility of bioinspired metal and metal oxide nanoparticles.

Fig. 5. A schematic representation of Au nanoclusters combined with porphyrin derivative (TSPP) utilized for fluorescence-based bioimaging and photothermal treatment to detect cancer (reproduced with permission from Y. Zhang, J. Li, H. Jiang, C. Zhao and X. Wang, RSC Adv., 2016, 6, 63331–63337 (ref. 67)).

Fig. 6. A schematic representation of the complete procedure of electrochemical biosensing utilizes the surface of the metal oxide nanofiber to immobilize the enzyme. This interaction between the enzyme and metal oxide nanofiber generates signals that are electrochemically detected and amplified (reproduced with permission from K. Mondal and A. Sharma, RSC Adv., 2016, 6, 94595–94616 (ref. 146)).

Fig. 7. Illustration of the mode of mechanism followed by metal and metal oxides to exhibit antibacterial activity against bacteria, like denaturing the protein, generating ROS, increasing oxidative stress inside the cell, and damaging the cell wall.

Fig. 8. Systematic mode of the mechanism of metal oxide nanoparticles loaded with drugs for delivering at the target cell by denaturing the cell's surface proteins.

Fig. 9. Schematic illustration showing the colorimetric detection of SARS on the AuNP-based strips. Strips are coated with antibodies (Abs) that hold the capacity to actively bind with viral antigens (Ag) present on SARS-COV-2 and can subsequently form a conjugate with AuNPs-conjugated secondary Abs. This conjugation will finally result in a color change, indicating the positivity of the tested sample (reproduced with permission from G. Ibrahim Fouad, Bull. Natl. Res. Cent., 2021, 45, 36 [CC BY 4.0] (ref. 258)).

Kshitij R. B. Singh

Vanya Nayak

Jay Singh

Ajaya Kumar Singh

Ravindra Pratap Singh