Polymeric scaffolds as building blocks for nanomaterials with biomedical applications

Functional polymers are emerging as strong candidates for a variety of biomedical applications, but progress in this field is slow due to the difficulties associated with the synthesis of libraries of polymers. Polymeric scaffolds facilitate the rapid synthesis of such functional polymers by employing click chemistries as a tool for post-polymerisation modification. Acrylic and acetylene based polyhydrazides have been explored as potential scaffolds for the in situ screening of functionalised polymers for biomedical applications. Poly(acryloyl hydrazide) was prepared from commercially available starting materials using RAFT polymerisation in a three step synthesis, and its postpolymerisation modification using a variety of hydrophilic and hydrophobic aldehydes was investigated. Biocompatible solvents and reaction conditions were determined such that the postpolymerisation modification could be achieved with good yields or better. The applicability of the scaffold was shown during the in situ screening of functional polymers for siRNA delivery, which required no isolation or purification of candidate polymers. Poly(4-ethynylbenzohydrazide) was synthesised using rhodium catalysed polymerisation conditions, towards achieving a helical polymer scaffold. Despite the lack of solubility in aqueous solvents, the stability and post-polymerisation modification was analysed in a variety of conditions, opening the possibility of synthesising biodegradable mimics to naturally occurring helical moieties