Preparation and characterization of a gene-activated matrix mimicking extracellular matrix

This study aims to establish a novel gene-activated matrix that mimics the structure and function of extracellular matrix (ECM-m-GAM). The structure, mechanical property and release profile were also characterized. Firstly, the liposome/DNA lipoplex (LPD) was modified with cell penetrating peptide TAT. The obtained TAT-LPD was then mixed with RGD grafting hyaluronic acid solution. After addition of the matrix metalloproteinase (MMPs) sensitive crosslinker (HS-MMP-SH), hyaluronic acid was crosslinked and TAT-LPD was encapsulated in the subsequently formed hydrogel. As a result, the cell adhesion factor RGD, MMPs sensitive substrate and the efficient gene transfer vector TAT-LPD were all integrated in the hyaluronic acid hydrogel, which was named as ECM-m-GAM. The release profile of DNA from ECM-m-GAM in different release medium was evaluated with PicoGreen kits. The results suggested that the mean diameter of the spherical TAT-LPD was (263.0 ±4.30) nm. TAT-LPD was successfully encapsulated in ECM-m-GAM, which had the typical porous network structure of hydrogels. The mechanical strength of GAM was enhanced with the increasing of hyaluronic acid content. When the content was 4%, the elastic modulus of GAM reached 1 600 Pa. The highly elastic GAM may be suitable for implantation and tissue regeneration. The DNA release showed significant MMPs sensitive property. Especially, the released DNA still existed in form of nanoparticles. Bone marrow mesenchymal stem cells (BMSCs) were successfully transfected with GAM and the green fluorescent protein was expressed. The results have laid a solid foundation for future study of the cell transfection and tissue regeneration.