Gold nanoparticles that absorb near-infrared (NIR) photons are known to efficiently convert light into heat for applications in photothermal therapy of cancer. Development of highly efficient near-infrared photothermal transducers is critical for treatment of highly aggressive cancers and/or large tumors where the penetration of light can be substantially reduced in the innermost part of the tissue. Herein, we report gold nanomatryoshkas (Au/SiO2/Au) as highly efficient photothermal transducers that improve the therapeutic efficacy in highly aggressive triple negative breast cancer (TNBC) tumors in vivo by benchmarking against gold nanoshells.A single dose of intravenous injection of gold nannomatryoshka in combination with a single NIR light laser dose of 2 W/cm2 for 3 min doubles the survival time of mice bearing large (~1000 mm3) TNBC tumors with respect to the control without nanoparticles. We show that gold nanomatryoshkas with a diameter of ~90 nm exhibit a higher absorption cross-section than the benchmark SiO2/Au nanoshells of ~150 nm. The higher absorption cross-section of a nanomatryoshka results in a higher efficiency of photonic to thermal energy conversion. Theoretical calculations of the optical spectrum explain that gold nanomatryoshkas are strong light absorbers with 77% absorption efficiency, but weak scatterers with 23% scattering efficiency. However, nanoshells are weak absorbers with 15% absorption efficiency, but strong scatterers with 85% scattering efficiency. In addition, we show that the accumulation of nanomatryoshkas in tumors is enhanced with respect to nanoshells due to their sub-100 nm diameter. Therefore, these nanomatryoshkas show a double enhancement effect in photothermal therapy by: 1) increasing accumulation of particles in the tumor and 2) the larger light-to-heat conversion efficiency due to the higher absorption efficiency.

Impact of nanoparticle size on photothermal therapy efficacy in triple negative breast cancer

247th National Meeting (2014)

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