Rational design of semiconducting polymer brushes as cancer theranostics
Photonic theranostics (PTs) generally contain optical agents for optical sensing of biomolecules and therapeutic components for converting light to heat or chemical energy. Semiconducting polymer nanoparticles (SPNs) as advanced PTs possessing good biocompatibility, stable photophysical properties, sensitive and tunable optical responses from ultraviolet to NIR II window (300-1700 nm) have recently aroused great interest. Although semiconducting polymers (SPs) with various building blocks being synthesized and developed to meet the demands of biophotonic applications, most of the SPNs were made by a nanoprecipitation method that used amphiphilic surfactants to encapsulate SPs. Such binary SPs micelles usually exhibit weakened photophysical properties of SPs and undergo dissociation in vivo. SP brushes (SPBs) are products of functional post-modifications of SP backbones, which endows unique features to SPNs (e.g. enhanced optical properties and multiple chemical reaction sites for the conjunction of organic/inorganic imaging agents and therapeutics). Furthermore, the SPBs-based SPNs can be highly stable due to the supramolecular self-assembly and/or chemical crosslinking. In this review, we highlight the recent progress in the development of SPBs for advanced theranostics.