Photodynamic therapy using LCST polymers exerting pH-responsive isothermal phase transition.

In photodynamic therapy (PDT), the inherent physicochemical properties of a photosensitizer (PS) critically affect its biodistribution and therapeutic outcome as well as side effect. Here, we developed a PS-polymer conjugate displaying isothermal hydrophilic-to-hydrophobic phase transition in response to tumorous acidic pH. The polymer backbone was poly(N-isopropylacrylamide (NIPAAm)/2-aminoisoprpylacrylamide (AIPAAm)) (P(NIPAAm/AIPAAm)), which shows lower critical solution temperature (LCST) of 30 °C.

Effect of multiple cyclic RGD peptides on tumor accumulation and intratumoral distribution of IRDye 700DX-conjugated polymers.

Strategic delivery of IRDye 700DX (photosensitizer) is a key for improving its effect in photodynamic therapy. In this study, we have synthesized IRDye 700DX-conjugated polymers containing multiple cyclic RGD peptides to deliver IRDye 700DX selectively to tumor cells and tumor-associated blood vessels overexpressing αβ integrin. Our polymer has a backbone of hydrophilic poly(ethylene glycol)-poly(L-glutamic acid) block copolymer, and cyclic RGD peptides are conjugated to side chains of the poly(L-glutamic acid) while IRDye 700DX is conjugated to the terminal of poly(ethylene glycol).

A general strategy to prepare different types of polysaccharide-graft-poly(aspartic acid) as degradable gene carriers.

Owing to their unique properties such as low cytotoxicity and excellent biocompatibility, poly(aspartic acid) (PAsp) and polysaccharides are good candidates for the development of new biomaterials. In order to construct better gene delivery systems by combining polysaccharides with PAsp, in this work, a general strategy is described for preparing series of polysaccharide-graft-PAsp (including cyclodextrin (CD), dextran (Dex) and chitosan (CS)) gene vectors. Such different polysaccharide-based vectors are compared systematically through a series of experiments including degradability, pDNA condensation capability, cytotoxicity and gene transfection ability.

Poly(aspartic acid)-based degradable assemblies for highly efficient gene delivery.

Due to its good properties such as low cytotoxicity, degradability, and biocompatibility, poly(aspartic acid) (PAsp) is a good candidate for the development of new drug delivery systems. In this work, a series of new PAsp-based degradable supramolecular assemblies were prepared for effective gene therapy via the host-guest interactions between the cyclodextrin (CD)-cored PAsp-based polycations and the pendant benzene group-containing PAsp backbones. Such supramolecular assemblies exhibited good degradability, enhanced pDNA condensation ability, and low cytotoxicity.