Silylated Precision Particles for Controlled Release of Proteins

With the recent advances in the development of novel protein based therapeutics, controlled delivery of these biologics is an important area of research. Herein, we report the synthesis of microparticles from bovine serum albumin (BSA) as a model protein using Particle Replication in Non-wetting Templates (PRINT) with specific size and shape. These particles were functionalized at room temperature using multifunctional chlorosilane that cross-link the particles to render them to slowly-dissolving in aqueous media. Mass spectrometric study of the reaction products of diisopropyldichlorosilane with individual components of the particles revealed that they are capable of reacting and forming cross-links. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were also used to confirm the functionalization of the particles. Cross sectional analysis using focused ion beam (FIB) and EDS proved that the functionalization occurs throughout the bulk of the particles and is not just limited to the surface. Circular dichroism data confirmed that the fraction of BSA molecules released from the particles retains its secondary structure thereby indicating that the system can be used for delivering protein based formulations while controlling the dissolution kinetics

Sensitized Photodecomposition of Organic Bisphosphonates By Singlet Oxygen

During efforts to stabilize metal oxide bound chromophores for photoelectrochemical applications, a novel photochemical reaction has been discovered. In the reaction, the bisphosphonate functional groups −C­(PO₃H₂)₂(OH) in the metal complex [Ru­(bpy)₂(4,4′-(C­(OH)­(PO₃H₂)₂bpy)]²⁺ are converted into −COOH and H₃PO₄. The reaction occurs by sensitized formation of ¹O₂ by the lowest metal-to-ligand charge transfer excited state(s) of [Ru­(bpy)₂(4,4′-(C­(PO₃H₂)₂(OH))₂(bpy))]²⁺* followed by ¹O₂ oxidation of the bisphosphonate substituent. A related reaction occurs for the bisphosphonate-based drug, risedronic acid, in the presence of O₂, light, and a singlet oxygen sensitizer ([Ru­(bpy)₃]²⁺ or Rose Bengal)