Shuian-Yin Lin

Enzymatic detachment of cells might damage important features and functions of cells and could affect subsequent cell‐based applications. Therefore, nonenzymatic cell detachment using thermosensitive polymer matrix is necessary for maintaining cell quality after harvesting. In this study, we prepared thermosensitive PNIPAm‐co‐AAc‐b‐PS and PNIPAm‐co‐AAm‐b‐PS copolymers and low critical solution temperature (LCST) was tuned near to body temperature. Then, spin coated polymer films were prepared for cell adhesion and thermal‐induced cell detachment. The alpha‐step analysis and scanning electron microscope image of the films suggested that the thickness of the films depends on the molecular weight and concentration which ranged from 206 to 1330 nm for PNIPAm‐co‐AAc‐b‐PS and 97.5–497 nm for PNIPAm‐co‐AAm‐b‐PS. The contact angles of the films verified that the polymer surface was moderately hydrophilic at 37°C. Importantly, RAW264.7 cells were convincingly proliferated on the films to a confluent of >80% within 48 h and abled to detach by reducing the temperature. However, relatively more cells were grown on PNIPAm‐co‐AAm‐b‐PS (5%w/v) films and thermal‐induced cell detachment was more abundant in this formulation. As a result, PNIPAm‐co‐AAm‐b‐PS (5%w/v) was further used to coat commercial cytodex 3 microcarriers for 3D cell culturing and interestingly enhanced cell detachment with preserved potential of recovery was observed at a temperature of below LCST. Thus, surface modification of microcarriers with thermosensitive PNIPAm‐co‐AAm‐b‐PS could be vital strategy for nonenzymatic cell detachment and to achieve adequate number of cells with maximum cell viability and functionality.

Polymer-based hydrogels demonstrate superior performance when used as wound dressing. An ideal dressing should possess an active healing function, absorb wound exudates, and provide a moist interface on the wound for rapid injury repair and the prevention of pain and injury during replacement of the dressing. Thus, the aim of this study was to develop a novel, reversible, smart, interpenetrating polymeric network (IPN) by utilizing the thermosensitive network of pluronic F127 (PF127) as a template to regulate the conformation of calcium-ion-crosslinked alginate. We found that the IPN hydrogels formed soft and elastic thermosensitive networks, retaining their form even after absorbing a large amount of wound exudate. The exterior of the hydrogels was made up of a rigid calcium alginate network that supported the entire hydrogel, promoting the stability of the vascular endothelial growth factor (VEGF) payload and controlling its release when the hydrogel was applied topically to wounds. Raman spectroscopy confirmed the layered structure of the hydrogel, which was found to easily disintegrate even after moderate rinsing of the wound with cold phosphate-buffered saline. Taken together, these results show that the IPN hydrogel developed in this study could be a promising delivery platform for growth factors to accelerate wound healing.