12 - Polymeric Micelles for Tumor Theranostics

Abstract

Polymeric micelles that self-assembled from amphiphilic block copolymers have attracted much attention for drug delivery and cancer theranostics, while several candidates are under clinical trial. Polymeric micelles are generally constructed to be 10–100nm in diameter, and composited with a hydrophilic shell which usually is composed of poly(ethylene glycol) (PEG) and a hydrophobic core. Polymeric micelles provide a good platform for cancer therapy and diagnosis (theranostics), which could co-load nucleic acids, anticancer drugs, and antibodies inside the core for therapy, while incorporating contrast agents (CAs) inside the core or conjugating on the surface for imaging. The PEG shell could protect the drugs inside the core from degradation by enzymes. Some targeting moieties, such as sugar, growth factors, phenylboronic acid, antibodies, and aptamer could be decorated on their surface to selectively interact with receptors that are highly expressed on tumor cells to increase the targeting ability. The polymeric micelles are stable in the blood circulation, which could enable delivery of drugs/CAs to tumor tissues through the enhanced permeability and retention effect. The targeting moieties of micelles could specifically interact with the epitopes that are overexpressed on cancer cells to increase the diagnostic selectivity and break down therapeutic limitations, which could also reduce their distribution in normal regions. Polymeric micelles with theranostic functions could be utilized for cancer diagnosis, image-guided therapy, tracing polymeric micelles in the body, and monitoring the therapeutic effects. In this chapter we focus on recent advances of polymeric micelles for tumor optical imaging, MRI, multifunctional imaging, image-guided therapy, and theranostics.