Synthesis and Characterization of a Novel Dual-Responsive Nanogel for Anticancer Drug Delivery.

In this study, to reduce the side effects of anticancer drugs and also to increase the efficiency of current drug delivery systems, a pH and temperature-responsive polymeric nanogel was synthesized by copolymerization of N-vinylcaprolactam (VCL) and acrylic acid (AA) monomers (P(VCL-co-AA)) with a novel cross-linker, triethylene glycol dimethacrylate (TEGDMA), as a biocompatible and nontoxic component. The structural and physicochemical features of the P(VCL-co-AA) nanogel were characterized by FT-IR, DLS/Zeta potential, FE-SEM, and 1HNMR techniques. The results indicated that spherical polymeric nanogel was successfully synthesized with a 182 nm diameter. The results showed that the polymerization process continues with the opening of the carbon-carbon double bond of monomers, which was approved by C-C band removing located at 1600 cm-1. Doxorubicin (Dox) as a chemotherapeutic agent was loaded into the P(VCL-co-AA), whit a significant loading of Dox (83%), and the drug release profile was investigated in the physiological and cancerous site simulated conditions. P(VCL-co-AA) exhibited a pH and temperature-responsive behavior, with an enhanced release rate in the cancerous site condition. The biocompatibility and nontoxicity of P(VCL-co-AA) were approved by MTT assay on the normal human foreskin fibroblasts-2 (HFF-2) cell line. Also, Dox-loaded P(VCL-co-AA) had excellent toxic behavior on the Michigan Cancer Foundation-7 (MCF-7) cell line as model cancerous cells. Moreover, Dox-loaded P(VCL-co-AA) had higher toxicity in comparison with free Dox, which would be a vast advantage in reducing Dox side effects in the clinical cancer treatment applications.

The Potential Applications of Hyaluronic Acid Hydrogels in Biomedicine.

Hyaluronic acid (HA) is widely used in the biomedicine due to its biocompatibility, biodegradability, and nontoxic properties. It is crucial for cell signaling role during morphogenesis, inflammation, and wound repair. After hydrogel formation, HA easily is converted to elastic sheets in order to use in preclinical and clinical applications. In addition, HA-derived hydrogels are easily used as vectors for cell and medication in tissue repairing and regenerative medicine. Moreover, in comparison with other polymers, HA -based hydrogels play a key role in in cellular behavior, including stem cell differentiation. The current paper reviews both basic concepts and recent advances in the development of HA-based hydrogels for biomedical applications.

In vivo articular cartilage regeneration through infrapatellar adipose tissue derived stem cell in nanofiber polycaprolactone scaffold.

In this study, we report the development of a nanofiber polycaprolactone scaffold that can act as a stem cell carrier to induce chondrogenesis and promote cartilage repair in vivo. Infrapatellar fat pads were obtained from sheep knee and the stem cells were isolated and characterized by flow cytometry. Defects were created in sheep knee, two defects received adipose tissue derived stem cells (ASCs)-polycaprolactone construct, second group received polycaprolactone (PCL), the third group was chosen as the ASCs group and the fourth group was control group. Morphological evaluation showed that defects treated with ASCs-scaffold constructs were completely filled with cartilage-like tissue, while other groups revealed the formation of a thin layer of cartilage-like tissue in the defects. Real-Time RT-PCR showed the increase in collagen type 2 mRNA levels, aggrecan and Sox9 in ASCs/PCL groups in comparison with the other groups. Immunofluorescence and toluidine blue staining results showed the protein expression of collagen type 2 and formation of round and polygonal clusters of chondrocytes in ASCS/PCL group. According to our results nanofiber polycaprolactone promoted the chondrogenesis of infrapatellar adipose tissue derived stem cells in vivo and could offer significant promise in the biological functionality of stem cell tissue engineering in clinical practice.