Plasmonic nanoparticles coupled with metallic films forming nanometer scale cavities have recently emerged as a powerful tool for enhancement of light-matter interaction. Despite high efficiency for sensing and light emission, such nanocavities exhibit harmful and uncontrolled optical heating which limits the ranges of light intensities and working temperature. In contrast to plasmonic nanoparticles, all-dielectric counterparts possess low Ohmic losses, high temperature stability along with a strong temperature-dependent Raman response. Here, we demonstrate that a silicon nanoparticle coupled with a thin gold film can serve as a multifunctional metal-dielectric (hybrid) nanocavity operating up to 1200 K. Resonant interaction of light with such nanocavity enables molecular sensing, heat-induced molecular events (protein unfolding), and their real-time tracing with a nanoscale thermometry through the monitoring enhanced Raman scattering both from the nanoparticle and analyzed molecules. We model numerically the thermo-optical properties of the hybrid nanocavity and reveal two alternative regimes of operation -with and without strong optical heating while other functionalities are preserved. We believe that the concept of the multifunctional hybrid nanocavities holds great potential for diverse photochemical and photophysical applications.

Interaction between nanoparticles and biomolecules leads to the formation of biocompatible or bioadverse complexes. Despite the rapid development of nanotechnologies for biology and medicine, relatively little is known about the structure of such complexes. Here, we report on the changes in conformation of a blood protein (bovine serum albumin) adsorbed on the surface of single all-dielectric nanoparticles (silicon and germanium) following light-induced heating to 640 K. This protein is considerably more resistant to heat when adsorbed on the nanoparticle than when in solution or in the solid state. Intriguingly, with germanium nanoparticles this heat resistance is more pronounced than with silicon. These observations will facilitate biocompatible usage of all-dielectric nanoparticles.

The synthesis of new biocomposites exhibiting a synergistic effect is a promising step in the healing of acute and chronic wounds. In the present study we have combined four materials: chlorhexidine digluconate as a antimicrobial agent, lidocaine as a painkiller, chymotrypsin as a necrolytic agent, and sol-gel processed alumina as a carrier for the sustained delivery of drugs and as an established wound healer. Composites were synthesized and characterized for surface morphology, crystalline structure and in vitro drug release. In vivo wound healing efficacy was assessed using a full thickness excision wound model in Wistar rats. The main result, was that a marked decrease in scar size was observed because of the wound healing composite, in fact the area of the scar in the test group of rats was 2.4 times smaller than that in the control group. Wound closure analysis revealed that complete epithelialization was observed after 15 AE 1 days using the biocomposite, whereas this took 17 AE 1 days and 19 AE 1 days using the healing solution alone or pure alumina gel, respectively. It was concluded that the synergistic combination of healing drugs, with sol-gel alumina as dressing material, provides a highly attractive biomaterial for the treatment of surface wounds, burns and foot ulcers.

New nanocomposite material based on sol–gel magnetite for wound healing is described. Composition and drug release profile provides 1.5 fold acceleration wound healing rate and 2 fold lesser scar size.