3-(4-5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2h-tetrazolium and caprolactone

Bone marrow-derived mesenchymal stem cell microtissues (BMSCMT) enhanced cardiomyogenesis in vitro and cardiac repairs of myocardial infarcted hearts in vivo are documented. Producing human BMSCMT onto patches in vitro for cardiac tissue engineering has not been reported. For possibly producing human bone marrow-derived mesenchymal stem cell microtissues (hBMSCMT) on an elastic silk fibroin (SF)-poly(ε-caprolactone) (PCL) based patches is hereby designed. After an elastic SF-PCL (SP) patch is fabricated, hyaluronic acid (HA)/SF-PCL(HSP) and HA-GRGD/SF-PCL(HGSP) patches are fabricated by photochemically grafting HA and HA-GRGD onto SP surfaces. The results show that the proliferations of hBMSC on HGSP patches significantly exceed those on the other patches, as determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Notably, the formation of 5-aza inducing cardiomyogenic differentiations of hBMSCMT/HGSP patches is observed with typical sizes of ≈317 μm wide and 26 μm high. The cardiomyogenesis of hBMSCMT/HGSP patches including the expressions of cardiac-specific genes (e.g., Gata4) and proteins (e.g., connexin43 (CX43)) significantly exceeds those of hBMSC monolayer on the HSP and SP patches. Promoting in vitro cardiomyogenesis of hBMSC with forming cardiomyogenic differentiation of hBMSCMT/HGSP hybrid patch is possibly mediated by the synergistic functions of HA-GRGD on enhancing the activity of F-actin. The hBMSCMT/HGSP cardiac patch may be further employed to cardiac tissue engineering.

Topics: Actins; Biocompatible Materials; Bone Marrow Cells; Caproates; Cell Differentiation; Cell Proliferation; Fibroins; Humans; Hyaluronic Acid; Lactones; Mesenchymal Stem Cells; Myocardial Infarction; Myocytes, Cardiac; Silk; Tetrazolium Salts; Thiazoles; Tissue Culture Techniques; Tissue Engineering; Tissue Scaffolds

Using the 3(rd) generation Grubbs' catalyst as the initiator, diblock brush polymer drug conjugates (BPDCs) were synthesized by sequential ring-opening metathesis polymerization (ROMP) of a hydrophilic poly(ethylene glycol) (PEG)-based norbornene (NB)-functionalized macromonomer and a hydrophobic paclitaxel (PTXL)-based NB-functionalized monomer. These amphiphilic diblock BPDCs had well-defined structures, with narrow molecular weight distributions (Mw/Mn = 1.10-1.16). They self-assembled into multi-molecular nanostructures in aqueous solutions. Although the PTXL moieties were connected to the backbone with cycloacetal-based conjugation linkages, the cleavage of these linkages from the assemblies of diblock BPDCs was relatively slow and exhibited limited acid-sensitivity, indicating a significant influence of the macromolecular structure and assembly of BPDCs on their drug release behaviour. The cytotoxicity study not only showed that the diblock BPDCs are therapeutically effective against cancer cells, but also revealed a correlation between cytotoxicity and grafting structures of BPDCs. In summary, the results obtained in this work provide new insight into the structure-dependent properties of brush polymer-based drug delivery systems.

Topics: Caproates; Cell Line; Drug Carriers; Drug Delivery Systems; Humans; Hydrophobic and Hydrophilic Interactions; Lactones; Macromolecular Substances; Molecular Structure; Norbornanes; Paclitaxel; Polyethylene Glycols; Polymerization; Polymers; Tetrazolium Salts; Thiazoles