Fast and safe fabrication of a free-standing chitosan/alginate nanomembrane to promote stem cell delivery and wound healing

Abstract

Yi Kong,1,2,* Rui Xu,1,* Mohammad Ali Darabi,2 Wen Zhong,3 Gaoxing Luo,1 Malcolm MQ Xing,1,2 Jun Wu1 1Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns, and Combined Injury, Chongqing Key Laboratory for Diseases Proteomics, Third Military Medical University, Chongqing, People’s Republic of China; 2Department of Mechanical Engineering, Biochemistry and Medical Genetics, Children’s Hospital Research Institute of Manitoba, 3Department of Biosystem Engineering, University of Manitoba, Winnipeg, MB, Canada *These authors contributed equally to this work Abstract: Polymeric ultrathin membranes that are compatible with cells offer tremendous advantages for tissue engineering. In this article, we report a free-standing nanomembrane that was developed using a layer-by-layer self-assembly technique with a safe and sacrificial substrate method. After ionization, two oppositely charged polyelectrolytes, alginate and chitosan, were alternately deposited on a substrate of a solidified gelatin block to form an ultrathin nanomembrane. The space between the two adjacent layers was ~200 nm. The thickness of the nanomembrane was proportional to the number of layers. The temperature-sensitive gelatin gel served as a sacrificial template at 37°C. The free-standing nanomembrane promoted bone marrow stem cell adhesion and proliferation. Fluorescence-activated cell sorting was used to analyze green-fluorescent-protein-positive mesenchymal stem cells from the wounds, which showed a significantly high survival and proliferation from the nanomembrane when cells were transplanted to mouse dorsal skin that had a full-thickness burn. The bone-marrow-stem-cell-loaded nanomembrane also accelerated wound contraction and epidermalization. Therefore, this methodology provides a fast and facile approach to construct free-standing ultrathin scaffolds for tissue engineering. The biocompatibility and free-standing nature of the fabricated nanomembrane may be particularly useful for stem cell delivery and wound healing. Keywords: nanomembrane, layer-by-layer, cell delivery, wound healing

Keywords

• nanomembrane
• layer-by-layer
• cell delivery
• wound healing