Hybrid CaCO 3 microparticles coated by sodium poly(styrene sulfonate) (PSS) and aliphatic poly(urethane-amine) (PUA) were developed as thermal-/pH-responsive drug delivery vehicles via LbL self-assembly technique. The DOX release from the CaCO 3 microparticles was higher than 60% within 36 h, whereas the value of PUA/PSS-coated microparticles was only 20%. The results demonstrated that the PUA/PSS multilayer coating could reduce the drug release rate and significantly assuage the initial burst release of DOX. In addition, the drug release of the hybrid microparticles was found to be thermal-/pH-dual responsive. More interestingly, more than 90% of DOX was released in 36 h at pH 2.1 and 55 °C owing to the combined action of the dissolution of the CaCO 3 core and the shrinkage of aliphatic PUA.
Yifeng Chen,Yiduo Chen,Wenzhong Cao,Jing Wang,Peng Zhang,Jian Ji
Implantable cardiovascular devices have revolutionized the treatment of cardiovascular diseases, yet their long-term functionality without causing thrombosis is a persistent challenge. Although the surface modification of anticoagulant coating has greatly improved the biocompatibility of the devices, its long-term stability in complex physiological environments still remains questionable. Herein, the stability of three anticoagulant hydrogel coatings, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(sodium 2-acryloyl-2-methylpropanesulfonate) (PAMPS), and poly(4-styrenesulfonate sodium) (PSS), is studied. The fabrication of these coatings onto device surfaces is validated by using X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. In vitro anticoagulation assays confirm the coatings’ significant anticoagulant effects. Among all three coatings, the PSS coating demonstrated superior chemical and mechanical stability in the comprehensive tests, showing great potential for improving the long-term anticoagulant performance of implantable cardiovascular devices.
PVA/PSS composite gel membrane electrode for membrane capacitive deionization (MCDI) was fabricated and characterised in the present study. The composite electrode with ion exchange surface is prepared by coating glutaraldehyde cross-linked polyvinyl alcohol (PVA) composite hydrogel, with Poly (Sodium 4-Styrenesulfonate) (PSS) added into the network, on the surface of activated carbon (AC) electrode. The feasibility of the gel membrane is analyzed by rheological, swelling rates and ion exchange capacity tests. Then electrochemical test and desalination test are used to study the performance of the MCDI electrode. The results show that coating of composite hydrogel layer improved the hydrophilicity, specific capacitance and lower interfacial electron transfer resistance of the electrode. Finally, we assemble the asymmetrical CDI cell with PVA/PSS composite gel electrode and AC electrode. Compared with the AC electrode, the salt adsorption capacity of PVA6-PSS15 can reach 18.9 mg g−1 and stable charge efficiency at 73.0% at operating voltage of 1.2 V. The decrease in specific capacitance of PVA6-PSS15 after 50 cycles is 1.33%, indicating that the electrode has a good cycling life. The gel membrane coated electrode prepared by PSS provides a new idea for the development of MCDI.
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