Photothermal Therapy of Temperature-sensitive Polymer/CuS Nanoparticles Composite Microspheres in Cancer

The copper sulfide (CuS) nano-particles which have the photothermal effect were prepared by wet chemical method. The polymer gel/copper sulfide [P (NIPAAm-co-NVP)/CuS (NNC/CuS) composite microspheres which possess both temperature sensitivity and photothermal effect were synthesized, using N-isopropylacrylamide (NIPAAm) and N-Vinylpyrrolidone (NVP) as monomers, laponite as crosslinking agents, then CuS nanoparticles were adsorbed. Drug delivery performance and drug controlled release properties were also studied. The results showed that both CuS nanoparticles and composite microspheres had a very wide spectral absorption band in the near infrared region. In the 980 nm (0.5 W/cm(2)) laser irradiation case, NNC/CuS composite microspheres exhibit a good photothermal effect, the temperature of composite microspheres can raise to 51.9 degrees C in 8 min. It can effetively kill Hela cell, the killing effect getting better with the increase of irradiation time. The drug loading is 0.15 mg/mg, the cumulative drug release rate is 75% at pH = 5.5 PBS buffer and 63% at pH = 7.4. The photothermal effect can also effectively regulate drug release from temperature sensitive drug loaded microspheres. In drug release phase, the drug release rate was much improved when treated with 980 nm laser irradiation. On the other hand, the cell toxicity of NNC/CuS composite microspheres was notably decreased. The cell viability of the composite microspheres was 90.9% compared with 63% of CuS nanoparticles.