Poly(oxanorbornene)-Coated CdTe Quantum Dots as Antibacterial Agents.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Antibiotic resistance in *Escherichia coli* poses a significant global health threat.
• Antimicrobial peptides (AMPs) are a promising alternative, but their clinical application is limited by stability and toxicity.
• Quantum dots (QDs) offer unique optical and electronic properties for biomedical applications.

Purpose of the Study:

• To synthesize and characterize poly(oxanorbornene) molecule (PONs)-coated cadmium telluride quantum dots (CdTe QDs).
• To evaluate the antibacterial activity of PONs-CdTe QDs against *Escherichia coli*.
• To compare the antibacterial and hemolytic activity of PONs-CdTe QDs with free PONs and free CdTe QDs.

Main Methods:

• Synthesis of PONs-CdTe QDs conjugates.
• Determination of minimum inhibitory concentration (MIC) against *E. coli*.
• Assessment of hemolytic activity against red blood cells.

Main Results:

• PONs-CdTe QDs exhibited concentration-dependent additive antibacterial activity against *E. coli*.
• The conjugates showed significantly lower MIC values compared to free PONs and QDs, especially those with high amine density PONs.
• Conjugation of PONs to CdTe QDs reduced hemolytic activity, leading to higher therapeutic indices.

Conclusions:

• PONs-CdTe QDs represent a promising strategy for combating antibiotic-resistant *E. coli*.
• The mechanism of action for PONs-CdTe QDs differs from free PONs.
• Reduced toxicity of PONs-CdTe QDs suggests potential for enhanced therapeutic efficacy in treating bacterial infections.