No abstract

No abstract

There is a great demand to understand cell transplantation, migration, division, fusion, and lysis. Correspondingly, illuminant object-labeled bioprobes have been employed as long-term cellular tracers, which could provide valuable insights into detecting these biological processes. In this work, we designed and synthesized a fluorescent polymer, which was comprised of hydrophilic N-isopropylacrylamide polymers as matrix and a hydrophobic tetraphenylethene (TPE) unit as AIE-active cross-linkers (DDBV). It was found that when the feed molar ratio of N-isopropylacrylamides to cross-linkers was 22:1, the produced polymers demonstrated the desirable LCST at 37.5 °C. And also, the temperature sensitivity of polymers could induce phase transfer within a narrow window (32-38 °C). Meanwhile, phase transfer was able to lead the florescent response. And thus, we concluded that two responses occur when one stimulus is input. Therefore, the new cross-linker of DDBV rendered a new performance from PNIPAm and a new chance to create new materials. Moreover, the resulted polymers demonstrated very good biocompatibility with living A549 human lung adenocarcinoma cells and L929 mouse fibroblast cells, respectively. Both of these cells retained very active viabilities in the concentration range of 7.8-125 μL/mg of polymers. Notably, P[(NIPAm)22-(DDBV)1] (P6) could be readily internalized by living cells with a noninvasive manner. The cellular staining by the fluorescent polymer is so indelible that it enables cell tracing for at least 10 passages.

Inspired by marine mussel adhesive proteins, polymers with catechol side groups have been extensively explored in industrial and academic research. Here, Pluronic L-31 alcoholate ions were used as the initiator to prepare a series of polypeptide-Pluronic-polypeptide triblock copolymers via ring-opening polymerization of l-DOPA-N-carboxyanhydride (DOPA-NCA), l-arginine-NCA (Arg-NCA), l-cysteine-NCA (Cys-NCA), and ε-N-acryloyl lysine-NCA (Ac-Lys-NCA). These copolymers demonstrated good biodegradability, biocompatibility, and thermoresponsive properties. Adhesion tests using porcine skin and bone as adherends demonstrated lap-shear adhesion strengths up to 106 kPa and tensile adhesion strengths up to 675 kPa. The antibleeding activity and tissue adhesive ability were evaluated using a rat model. These polypeptide-Pluronic copolymer glues showed superior hemostatic properties and superior effects in wound healing and osteotomy gaps. Complete healing of skin incisions and remodeling of osteotomy gaps were observed in all rats after 14 and 60 days, respectively. These copolymers have potential uses as tissue adhesives, antibleeding, and tissue engineering materials.

No abstract