Major Research Findings

Colloidal silver has garnered attention in the medical field due to its antibacterial properties. 3 study showed that green synthesized colloidal silver (GSCS) does not exhibit toxic effects on primary human nasal epithelial cells. On the other hand, 8 research demonstrated that gold-silver alloy nanoparticles (AgAu NPs) can penetrate Staphylococcus aureus. Furthermore, this study revealed that silver ions are released from AgAu NPs and transformed into pure silver nanoparticles (less than 10nm) within bacteria. This phenomenon can be explained by the reduction of silver ions by microbes.

Moreover, 10 study reported a rapid, high-yield, bioinspired method for synthesizing colloidal silver nanoparticles using Glycyrrhiza glabra root extract. This method enabled the synthesis of nanoparticles with high antibacterial effects. Additionally, 11 study showed that nanosilver can alleviate foreign body reactions and facilitate wound repair by regulating macrophage polarization. A nanosilver-containing collagen-chitosan hybrid scaffold (NAg-CCS) was found to suppress foreign body reactions and promote wound healing. However, 12 research evaluated the toxicity of colloidal silver nanoparticles (Ag NPs) functionalized with olive leaf extract and oleuropein on human trophoblast cells and peripheral blood lymphocytes. The results showed that Ag NPs exhibited cytotoxicity, with Ag/OLE showing the most pronounced cytotoxicity.

13 study synthesized quercetin- and caffeic acid-functionalized chitosan-capped colloidal silver nanoparticles (Ch/Q- and Ch/CA-Ag NPs) and evaluated their antibacterial and anticancer activities. The results indicated that Ch/Q-Ag NPs were more effective against cancer cell lines compared to healthy cells. Additionally, 14 research highlighted the potential of nanosilver-functionalized polysaccharides as a platform for wound dressings. Naturally sourced polysaccharides hold great promise as wound dressings due to their availability, affordability, and biocompatibility. Furthermore, nanosilver has been widely used in wound treatment due to its broad-spectrum antimicrobial effects and lower drug resistance. As a result, wound dressings incorporating nanosilver have gained significant interest in wound healing, and nanosilver-functionalized polysaccharide-based wound dressings offer an affordable option for healing chronic wounds.

Benefits and Risks

Benefit Summary

Colloidal silver has the potential to promote wound healing due to its antibacterial properties. It has also been reported to reduce foreign body reactions by regulating macrophage polarization. Furthermore, the development of synthesis methods using plant-derived components is ongoing, leading to the development of safe and effective nanoparticles. However, some studies have reported cytotoxicity, so safety confirmation is necessary.

Risk Summary

Colloidal silver can exhibit cytotoxicity when used at high concentrations. There are also reports of genotoxic effects. Therefore, caution is advised when using colloidal silver.

Comparison between Studies

Commonalities

Multiple studies have demonstrated the antibacterial properties of colloidal silver. Additionally, there is evidence suggesting that colloidal silver can promote wound healing.

Differences

The synthesis methods and effects of colloidal silver vary across studies. For example, 10 research reported a rapid, high-yield, bioinspired method for synthesizing colloidal silver nanoparticles using Glycyrrhiza glabra root extract. In contrast, 12 research used olive leaf extract and oleuropein to synthesize colloidal silver nanoparticles. The synthesis method can affect the characteristics of the nanoparticles, potentially leading to differences in their effects.

Consistency and Contradictions in Results

While multiple studies have demonstrated the antibacterial effects of colloidal silver, its efficacy and safety require further investigation. Notably, there are discrepancies in the reported cytotoxicity of colloidal silver. Thus, further research on the safety of colloidal silver is warranted.

Considerations for Real-World Application

Colloidal silver, with its antibacterial properties, has potential applications in wound healing and food preservation. However, high concentrations of colloidal silver can lead to cytotoxicity, and genotoxic effects have been reported. Therefore, thorough safety assessment is crucial when incorporating colloidal silver into products. Additionally, colloidal silver is not approved as a pharmaceutical drug by regulatory bodies, limiting its use as a medication. Even as a health food, its efficacy and safety remain unclear, so caution is advised.

Limitations of Current Research

Current research has not fully elucidated the safety and efficacy of colloidal silver. Long-term safety and potential human health impacts remain largely unknown. Furthermore, the mechanism of action of colloidal silver needs further investigation.

Future Research Directions

To gain a clearer understanding of the safety and efficacy of colloidal silver, further research is necessary. Studies evaluating long-term safety and human health impacts are essential. Elucidating the mechanism of action of colloidal silver can pave the way for safer and more effective utilization methods.

Conclusion

Colloidal silver, with its antibacterial properties, holds promise for wound healing and food preservation. However, its safety and efficacy need thorough investigation. Therefore, caution is advised when using colloidal silver. Future research is expected to shed light on its safety and efficacy, leading to better understanding and utilization of this material.