Tailoring Plasmonic Nanoheaters Size for Enhanced Theranostic Agent Performance

Area of Science:

• Nanomedicine
• Biomedical Engineering
• Materials Science

Background:

• Theranostic agents integrate diagnostic and therapeutic functions.
• Optimized plasmonic nanoheaters are crucial for effective nanomedicine.
• Selecting high-performance nanoheaters requires a suitable figure of merit.

Purpose of the Study:

• To establish a framework for optimizing metallic nanoparticles for heat generation.
• To identify high-performance plasmonic theranostic agents using the Joule number (Jo).
• To evaluate the size dependence of optical heating in plasmonic nanoparticles.

Main Methods:

• Utilized the Joule number (Jo) as a figure of merit for nanoheater performance.
• Investigated size-dependent optical heating of gold nanospheres (AuNSs) and gold nanorods (AuNRs).
• Evaluated photothermal performance using photoacoustic imaging and photothermal therapy in S180-bearing mice.

Main Results:

• Identified 50 nm AuNSs and 41×10 nm AuNRs as effective nanoheaters.
• AuNRs demonstrated higher Jo values than AuNSs, indicating superior heat generation efficiency.
• Optimized nanoparticles (41×10 nm AuNRs) showed enhanced temperature rise in photothermal therapy compared to larger nanoparticles (90×25 nm AuNRs).

Conclusions:

• The Joule number (Jo) is a reliable metric for selecting optimal plasmonic nanoheaters.
• Optimized nanoparticle size and shape significantly enhance photothermal conversion efficiency.
• Development of economical theranostic agents is facilitated by optimizing nanoheaters for reduced concentration or light fluence.