A PNIPAAm-based thermosensitive hydrogel containing SWCNTs for stem cell transplantation in myocardial repair.

Poly (N-isopropylacrylamide) (PNIPAAm) hydrogel was a widely used carrier in therapeutic agent delivery. However, its bioactivities for encapsulated cells were not satisfactory. In the study, we aimed to determine whether modification with single-wall carbon nanotubes (SWCNTs) could improve the bioactivitis, especially supportive adhesion of PNIPAAm to encapsulated cells and favor their efficacy in myocardial repair. A thermosensitive SWCNTs-modified PNIPAAm hydrogel (PNIPAAm/SWCNTs) were prepared by incorporating the SWCNTs into base PNIPAAm hydrogel. The bioactivities of the resulted hydrogel to brown adipose-derived stem cells (BASCs) were evaluated and compared with the base PNIPAAm hydrpgel in vitro. Then, the PNIPAAm-containing hydrogel was used as carrier for imtromyocardial delivery of BASCs in rats with myocardial infarction. The efficacy of PNIPAAm/SWCNTs hydrogel in stem cell-based myocardial repair was systematically evaluated. In vitro study showed that the PNIPAAm/SWCNTs hydrogel demonstrated significantly higher bioactivities to encapsulated BASCs compared with onefold PNIPAAm hydrogel, including promoting cell adhesion and proliferation. When used as carrier for intramyocardial delivery of BASCs after myocardial infarction, the PNIPAAm/SWCNTs hydrogel significantly enhanced the engraftment of seeding cells in infarct myocardium and augmented their therapeutic efficacies in myocardial infarction (MI). The data provided a supportive evidence for the myocardial application of the SWCNTs-modified hydrogel and offered a new perspective in development or improvement of cardiac tissue engineering scaffold.

Nanomaterials and nanotechnology for skin tissue engineering.

A recent literature review of the field shows that tissue-engineered skin has been in clinical use for the last several decades and that, over this time the technology has advanced rapidly. Despite this progress no synthetic skin yet produced has completely replicated normal, healthy skin. Therefore, researchers must continue to develop materials that successfully overcome the problems with current skin tissue substitutes. This paper is a comprehensive review of the prospects for nanotechnology and nanomaterials to close this gap by mimicking surface properties for reconstruction of a variety of skin tissues. In addition, a number of commercially available products that regenerate different layers of the burn-damaged or chronically wounded skin are reviewed.