 |
The stimuli-responsive polymer micelles can respond to external environmental stimuli such as pH, temperature, light, oxidants, enzymes, and ultrasonic irradiation, and have been widely used in many fields such as drug carriers, sensors, nano-devices, and the like. However, the traditional stimuli-responsive polymers have the defects that they have a single response and cannot be controlled in real time, which limits their further development and application.
Li Bangjing, a researcher at the Chengdu Institute of Biology, Chinese Academy of Sciences, has long devoted himself to the study of self-assembled biomedical materials based on cyclodextrin host-guest recognition, aiming at the defects of traditional stimuli-responsive polymer micelles, and using orthogonal self-assembly of homopolymers. Method (Homopolymer Orthogonal Self-Assembly, HOSA) using ferrocene-modified polyethylene glycol monomethyl ether (mPEG-Fc) and β-cyclodextrin as the reversible host-guest recognition of cyclodextrin and ferrocene Refined N-isopropyl acrylamide (PNIPAM-β-CD) constructs supramolecular block copolymer mPEG-Fc/PNIPAM-β-CD via reversible non-covalent linkage, and studies its oxidant and temperature Dual environment stimulates responsive behavior. In aqueous solution, the fully hydrophilic supramolecular block copolymer mPEG-Fc/PNIPAM-β-CD becomes an amphiphilic molecule when the temperature is higher than the PNIPAM's lower critical solution temperature (LCST). , And further self-assembled in water for micelle structure for drug packaging (as shown).
When hydrogen peroxide is added as an oxidant, due to the oxidation of ferrocene hydrogen peroxide to a positively charged ionized Fc+, Fc+ does not generate inclusions with the cyclodextrin, resulting in the collapse of the original inclusion structure and accompanied by partial release of the drug. The molecular block copolymers were changed to mPEG-Fc+ and PNIPAM-β-CD. Since the temperature is still above the LCST of the PNIPAM, the PNIPAM-β-CD can be reassembled to form a secondary micelle structure with a PNIPAM segment as the hydrophobic core and β-CD as the hydrophilic shell. Some drugs are entrapped in this secondary micelle structure. When the temperature of the system is further lowered below the LCST of the PNIPAM, the PNIPAM chain becomes completely hydrophilic, causing the secondary micelle structure to collapse, accompanied by complete release of the drug. The micellar system has excellent controllable release characteristics, and can utilize a high concentration of H2O2 environment in the tumor cells and a simple ice cooling or cryoprobe method to achieve quantitative drug release.
Related articles were published in the international magazine ACS Macro Letters.
Pool LED Light for Concrete pool
Pool Led Light For Concrete Pool,Swimming Pool Light,Waterproof Concrete Pool Light,Waterproof Led Strip Lights
Guangzhou Qshine Pool Lights Manufacture Co., Ltd , https://www.qshinepoollight.com