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Biodegradable and biocompatible hyperbranched polymers are synthesized and their potential for dermal drug delivery is investigated.

Despite immense investigations in the field of cancer diagnosis and therapy in recent decades, cancer is still the major cause of morbidity and mortality all over the world. Recently, with the advancement of nanotechnology, designing and preparation of efficient nano-sized structures having the potential of diagnosis and treatment of cancer have been proposed. Among different types of nano-sized materials, biocompatible polymers are seemed to be innovative tools with huge potential in cancer treatment. Advancement in polymer chemistry 10 55 gene delivery 2-7 , cancer diagnosis and therapy 8-11 , nanocarriers 12, 13 , nanomedicine 14-16 , and biomedical applications.

In this work we report on a new method for the cationic polymerization of glycidol by citric acid at ambient and solvent free conditions. In this polymerization, citric acid is a proton donor and is able to incorporate in the structure of polyglycerol by reaction with the activated monomer. The molecular weight and degree of branching of the synthesized polymers are affected by the glycidol/citric acid molar ratios and reaction temperature. Due to the citric acid core of the hyperbranched polyglycerols, they are able to break down into the smaller segments at neutral or acidic conditions. Apart from citric acid, glycidol, and water, other reagents or organic solvents have not been used in the synthetic and purification processes. Taking advantage of the green synthesis and ability to cleave under physiological conditions, in addition to the intrinsic biocompatibility of polyglycerol, the synthesized polymers are promising candidates for future biomedical applications.

Scattering particles constitute a key light trapping solution for thin film photovoltaics where either the particles are embedded in the light absorbing layer or a thick layer of them is used as a reflector. Here we introduce a monolayer of wavelength-scale core-shell silica@Ag particles as a novel light trapping strategy for thin film photovoltaics. These particles show hybrid photonic-plasmonic resonance modes that scatter light strongly and with small parasitic absorption losses in Ag (<1.5%). In addition, their scattering efficiency does not vary significantly with the refractive index of the surrounding medium. A monolayer of these particles is applied as the top-scattering layers in a dye-sensitized solar cells and it improves the short-circuit current density of a cell with 7 μm-thick dye-sensitized layer by 38%. Optical measurements of the scattering properties of these particles confirm that the strong scattering and low-parasitic absorption losses constitute the main reason for this efficient light trapping.