Pharmaceutical aspects of silver nanoparticles

Abstract

Silver nanoparticles are particles in the size ranging between 1 and 100 nm. The two major methods used for synthesis of silver nanoparticle are the physical and chemical methods with the disadvantage that they are expensive and can also have toxicity. Biological method is being used as an expedient alternative, as this approach is environment-friendly and less toxic and it includes plant extracts, microorganism, fungi, etc. The major applications of silver nanoparticles in the medical field include diagnostic applications and therapeutic applications, apart from its antimicrobial activity. Due to their nanotoxicity, AgNPs have a several drawbacks too. This review presents a complete view of the mechanism of action, synthesis, the pharmacokinetics of silver nanoparticles, different formulations of AgNPs used in biomedical applications, infertility management, antibacterial effects, skin damage, burns, cancer treatment, etc. and various applications of silver nanoparticles together with the possible toxicological challenge.

Ångstrom‐Scale Silver Particles as a Promising Agent for Low‐Toxicity Broad‐Spectrum Potent Anticancer Therapy

“…We also assessed the cytotoxic effects of fructose‐coated AgNPs (F‐AgNPs; F‐AgNPs diameter: 52.75 ± 5.25 nm, AgNPs diameter: 32.60 ± 3.48 nm) on cancer cell lines including BxPC‐3, PC‐3, CNE1, SW480, EC109, and MDA‐MB‐231 by CCK‐8 assay. The results showed that F‐AgNPs exhibited a much lower ability than F‐AgÅPs to inhibit the viability of these cancer cells with IC 50 values >40.5 ng µL −1 (Figure S1b, Supporting Information), which was consistent with the data of previous studies showing that the smaller particles usually have a stronger cytotoxicity . Interestingly, F‐AgÅPs did not show remarkable effects toward many human normal cell lines including vascular smooth muscle cells (VSMC), human microvascular endothelial cells (HMEC), hepatocytes (LO2), and embryonic kidney cells (293FT), resulting in high median IC 50 values (Figure S1c, Supporting Information).…”

“…Alternatively, nanoparticles can passively penetrate the cell membranes and invade subcellular compartments, owing to their small size . Nanoparticles with smaller size have a much stronger penetration ability and greater cytotoxicity, which may better explain why F‐AgÅPs exhibited more potent anticancer effects than F‐AgNPs. Very small particles may, however, easily extravasate across the normal endothelium (that requires sizes less than 1–2 nm) into the surrounding healthy tissues and be rapidly cleared by the kidney as the threshold for the first‐pass elimination by the kidney is around 10 nm .…”

“…Nanoparticles with sizes of 10–100 nm have been suggested to be optimal for cancer therapy, as the particles of these sizes can penetrate the leaky vasculature of tumors, but be restricted from exiting normal vasculature and thereby avoid the rapid renal clearance . AgNPs with smaller size usually have a stronger penetration ability and greater cytotoxicity . Thus, how to obtain AgNPs with the smallest possible sizes as well as efficient tumor accumulation ability has become an important issue for AgNPs‐based cancer therapy.…”

“…The chemical methods employ chemical reducing agents, such as borohydride, citrate, or other organic solvents, which are harmful to human body and hence render them unsuitable for medical purpose . Biological routes using microorganisms are considered safe, nontoxic, and eco‐friendly, but the synthesis methods have potential biohazard risks and require strenuous process of maintaining microbe cultures . In physical approaches, evaporation–condensation and laser ablation are usually used for deriving AgNPs from metal samples .…”

Limitations of Recent Studies Dealing with the Antibacterial Properties of Silver Nanoparticles: Fact and Opinion

“…Thus, the preparation of NPs colloidal solution implies a solvent, a metal source, a reductant and a stabilizer. Several recent review papers describe the different strategies to design NPs, more specifically silver ones for biomedical applications [53][54][55][56][57][58]. In some cases, a unique compound can be used as solvent, reductant and stabilizers or as reductant and stabilizer-e.g., polyol process or citrate-based approach, respectively [59].…”