Poly-l-lysine (PLL) nanoparticle (NP) system was prepared for the controlled release of curcumin (CUR) by pH stimuli, and its theranostic efficacy on cancer was compared to that of CUR solution in vitro and in vivo. Deoxycholic acid (DOCA), methoxy polyethylene glycol (MPEG) and cyanine 5.5 (cy5.5) were conjugated to the amine group of PLL through condensation reaction (PLL-DOCA-MPEG-cy5.5), followed by encapsulation of CUR by dialysis method (PLL-DOCA-MPEG-cy5.5/CUR NPs). The composition, morphology and size distribution of PLL-DOCA-MPEG-cy5.5 NPs were characterized by proton nuclear magnetic resonance (¹H NMR), transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. In vitro tests exhibited that changes in the charge and size of the NPs at low pH led to the improved cellular uptake of CUR into human hepatoma Hep3B cell line by electrostatically absorptive endocytosis. PEGylation with MPEG was turn out to be very effective to have a prolonged blood circulation time, in turn increased the EPR effect. In addition, the incorporation of Cy5.5 into NPs provided successful biodistribution images in vivo and ex vivo. Our findings suggest that PLL-DOCA-MPEG-cy5.5/CUR NPs may have promising applications in cancer theranosis.

The aim of this study was to investigate the osteogenic potential of bone marrow-derived mesenchymal stem cells (BMSCs) seeded on novel thermosensitive in situ forming hydrogel systems comprising methoxy polyethylene glycol-polycaprolactone (MP) and RGD-conjugated MP (MP–RGD) in vitro and in vivo. Real-time polymerase chain reaction (PCR) together with immunofluorescence staining revealed the strong expression of osteogenic markers (collagen 1 and osteocalcin) of BMSCs in MP/MP–RGD samples compared to MP samples. PCR array testing also showed the upregulation of the interconnected signaling networks regulating cell proliferation and differentiation, which was further verified through the Kyoto Encyclopedia of Genes and Genomes pathway analysis. Histological findings and computed tomographic analysis demonstrated that the MP/MP–RGD hydrogel dramatically promoted new bone formation in a rabbit calvarial defect model. In conclusion, this hydrogel appears to elicit cellular behaviors desired for bone tissue regeneration.

For patients with severe burns that consist of contractures induced by fibrous scar tissue formation, a graft must adhere completely to the wound bed to enable wound healing and neovascularization. However, currently available grafts are insufficient for scar suppression owing to their nonuniform pressure distribution in the wound area. Therefore, considering the characteristics of human skin, which is omnidirectionally stretched via uniaxial stretching, we proposed an auxetic skin scaffold with a negative Poisson’s ratio (NPR) for tight adherence to the skin scaffold on the wound bed site. Briefly, a skin scaffold with the NPR effect was fabricated by creating a fine pattern through 3D printing. Electrospun layers were also added to improve adhesion to the wound bed. Fabricated skin scaffolds displayed NPR characteristics (−0.5 to −0.1) based on pulling simulation and experiment. Finger bending motion tests verified the decreased marginal forces (<50%) and deformation (95%) of the scaffold comprising rarely dead cells and their spindle-shaped morphologies revealed the high cytocompatibility of the developed scaffold. Overall, the developed skin scaffold may help reduce wound strictures in the joints of patients with burns as it exerts less pressure on the wound margin.