Photothermal ablation therapy for cancer based on metal nanostructures

Besides conventional surgery, radiation therapy, and chemotherapy, which all tend to have side-effects and damage normal tissues, new medical strategies, such as photothermal sensitization and photo-thermal ablation therapy (PTA) with near-IR laser light, have been explored for treating cancer. Much of the current excitement surrounding nanoscience is directly connected to the promise of new nanotechnology for cancer diagnosis and therapy. The basic principle behind PTA is that heat generated from light can be used to destroy cancer cells. Strong optical absorption and high efficiency of photothermal conversion at the cancer sites are critical to the success of PTA. Because of their unique optical properties, e.g., strong surface plasmon resonance (SPR) absorption, noble metal nanomaterials, such as gold and silver, have been found to significantly enhance photothermal conversion for PTA applications. Substantial effort has been made to develop metal nanostructures with optimal structural and photothermal properties. Ideal metal nanostructures should have strong and tunable SPR, be easy to deliver, have low toxicity, and be convenient for bioconjugation for actively targeting specific cancer cells. This review would highlight some gold nanostructures with various shapes and properties, including nanoparticles (NPs), nanorods (NRs), nanoshells, nanocages, and hollow nanospheres, which have been studied for PTA applications. Among these structures, hollow gold nanospheres (HGNs) exhibit arguably the best combined properties because of their small size (30―50 nm), spherical shape, and strong, narrow, and tunable SPR absorption.

CuS-PNIPAm nanoparticles with the ability to initiatively capture bacteria for photothermal treatment of infected skin

Copper sulfide nanoparticles(CuS NPs)have shown great potential in various application fields,especially in biomedical engineering fields.CuS NPs,with the ability to actively capture and kill bacteria and without the worry of biocompatibility,will greatly expand their applications.Herein,a four-arm star thermosensitive polyisopropylacrylamide(4sPNIPAm)was used to modify CuS NPs(CuS-PNIPAm NPs).The obtained NPs displayed the controlled release of copper ions and higher photothermal conversion ability in comparison with contrast materials CuS-PEG NPs and CuS NPs.Aggregation of CuS-PNIPAm NPs at above 34℃resulted in capturing bacteria by forming the aggregates of NPs-bacteria.Both Staphylococcus aureus and Escherichia coli co-cultured with CuS-PNIPAm NPs were completely killed upon near-infrared irradiation in minutes.Furthermore,CuS-PNIPAm NPs were verified to be a photothermal agent without toxic effect.In in vivo experiment,the NPs effectively killed the bacteria in the wound and accelerated the process of wound repairment.Overall,photothermal treatment by CuS-PNIPAm NPs demonstrates the ability to actively capture and kill bacteria,and has a potential in the treatment of infected skin and the regeneration of skin tissues.The therapy will exert a far-reaching impact on the regeneration of stubborn chronic wounds.

Recent research progress on mixed valence state tungsten based materials

Synthesis and characterization of tungsten based mixed valence state nanoparticles and their novel applications are reviewed.The mixed valence state tungsten based homogeneous nanomaterials such as bronze structure M_(x)WO_(3)(M=Na^(+),K^(+),Rb^(+),Cs^(+),NH_(4)^(+),etc.)and tungsten sub-oxide W_(18)O_(49) possess excellent infrared(IR)light shielding property,implying their great potential applications on heat ray shielding and indoor energy saving effect in summer season.Also,some novel properties such as electric conductivity,bio thermal therapy function and electrochromic properties of mixed valence state tungsten based materials are introduced.The design of components,formation of composites and structure control of thin films are expected to realize the property enhancement and candidates for practice application as window materials.The multifunc-tionality of the mixed valence state based composites also implies great potential on novel applications of various building materials.