Biocompatible gold nanorods: one-step surface functionalization, highly colloidal stability, and low cytotoxicity

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Materials Science

Background:

• Gold nanorods (AuNRs) are widely used in biomedical applications.
• Cytotoxicity of AuNRs is often linked to synthesis reagents like CTAB and silver ions.
• Current PEGylation methods result in incomplete surface modification, limiting AuNRs' safety profile.

Purpose of the Study:

• To develop a facile, one-step method for complete surface functionalization of AuNRs with PEG.
• To enhance the biocompatibility and reduce the cytotoxicity of AuNRs.
• To overcome the limitations of partial PEGylation on AuNR surfaces.

Main Methods:

• Utilized Tween 20 for AuNR stabilization.
• Employed bis(p-sulfonatophenyl)phenylphosphine (BSPP) for surface activation.
• Incorporated NaCl for silver etching and complete CTAB removal.
• Achieved one-step surface functionalization and PEGylation.

Main Results:

• Successfully removed surface-bound CTAB and active silver ions.
• Produced fully PEGylated AuNRs with significantly reduced cytotoxicity.
• Demonstrated no apparent toxicity below 5 μg/mL concentration.
• Showcased four times higher cell viability at 80 μg/mL compared to tip-modified AuNRs.

Conclusions:

• The novel one-step method provides a superior approach for producing less toxic AuNRs.
• Complete PEGylation is crucial for mitigating AuNR cytotoxicity.
• This method offers a promising strategy for safer application of AuNRs in nanomedicine.