Aptamer-guided upconversion nanoconstructs enable proximity-dependent and precise photodynamic therapy for...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Antimicrobial Therapies

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) infections impede wound healing due to slow repair.
• Conventional photodynamic therapy (PDT) causes non-specific oxidative damage, hindering wound recovery.
• Developing targeted antibacterial strategies is crucial for managing drug-resistant infections and improving wound healing.

Purpose of the Study:

• To design and evaluate a DNA aptamer-functionalized upconversion nanoplatform for targeted antibacterial treatment of MRSA.
• To achieve spatially confined, proximity-dependent killing of MRSA while minimizing damage to healthy tissues.
• To investigate the efficacy and biosafety of the nanoplatform for treating MRSA-infected wounds.

Main Methods:

• Construction of an upconversion nanoplatform (UC@PEI-RB@Apt) with DNA aptamers for specific MRSA targeting.
• Utilizing upconversion nanoparticles (UCs) to convert near-infrared (NIR) light into visible light for Rose Bengal (RB) activation.
• Generating reactive oxygen species (ROS) in proximity to bacteria for targeted bacterial elimination.
• Evaluating *in vitro* bactericidal efficiency and biofilm disruption, and *in vivo* wound healing efficacy and biosafety in a murine model.

Main Results:

• The UC@PEI-RB@Apt nanoplatform demonstrated excellent targeting and biofilm disruption capabilities *in vitro*, achieving 99.9% bactericidal efficiency.
• Localized treatment significantly reduced bacterial load and accelerated wound closure in an *in vivo* MRSA-infected wound model.
• Histological analysis confirmed excellent biosafety, with negligible damage to surrounding tissues and major organs.

Conclusions:

• The aptamer-guided nanoplatform offers a precise and effective strategy for combating MRSA infections.
• This approach successfully balances high bactericidal activity with enhanced tissue safety.
• The developed technology shows significant potential for managing drug-resistant infections and promoting wound healing.