Cartilage is frequently damaged with a limited capacity for repair. Current treatment strategies are insufficient as they form fibrocartilage as opposed to hyaline cartilage, and do not prevent the progression of degenerative changes. There is increasing interest in the use of autologous mesenchymal stem cells (MSC) for tissue regeneration. MSCs that are used to treat articular cartilage defects must not only present a robust cartilaginous production capacity, but they also must not cause morbidity at the harvest site. In addition, they should be easy to isolate from the tissue and expand in culture without terminal differentiation. The source of MSCs is one of the most important factors that may affect treatment. The infrapatellar fat pad (IPFP) acts as an important reservoir for MSC and is located in the anterior compartment of the knee joint in the extra-synovial area. The IPFP is a rich source of MSCs, and in this review, we discuss studies that demonstrate that these cells have shown many advantages over other tissues in terms of ease of isolation, expansion, and chondrogenic differentiation. Future studies in articular cartilage repair strategies and suitable extraction as well as cell culture methods will extend the therapeutical application of IPFP-derived MSCs into additional orthopedic fields, such as osteoarthritis. This review provides the latest research concerning the use of IPFP-derived MSCs in the treatment of articular cartilage damage, providing critical information for the field to grow.

The effects of double release of insulin-like growth factor I (IGF-I) and growth factor β1 (TGF–β1) from nanoparticles on the growth of bone marrow mesenchymal stem cells and their differentiation into cartilage cells were studied on PLGA scaffolds. The release was achieved by using nanoparticles of poly(lactic acid-co-glycolic acid) (PLGA) and poly(N-isopropylacrylamide) (PNIPAM) carrying IGF-I and TGF–β1, respectively. On tissue culture polystyrene (TCPS), TGF-β1 released from PNIPAM nanoparticles was found to have a significant effect on proliferation, while IGF-I encouraged differentiation, as shown by collagen type II deposition. The study was then conducted on macroporous (pore size 200–400 µm) PLGA scaffolds. It was observed that the combination of IGF-I and TGF-β1 yielded better results in terms of collagen type II and aggrecan expression than GF-free and single GF-containing applications. It thus appears that gradual release of a combination of growth factors from nanoparticles could make a significant contribution to the quality of the engineered cartilage tissue. Copyright © 2011 John Wiley & Sons, Ltd.

New gelatin methacryloyl (GelMA)—strontium-doped nanosize hydroxyapatite (SrHA) composite hydrogel scaffolds were developed using UV photo-crosslinking and 3D printing for bone tissue regeneration, with the controlled delivery capacity of strontium (Sr). While Sr is an effective anti-osteoporotic agent with both anti-resorptive and anabolic properties, it has several important side effects when systemic administration is applied. Multi-layer composite scaffolds for bone tissue regeneration were developed based on the digital light processing (DLP) 3D printing technique through the photopolymerization of GelMA. The chemical, morphological, and biocompatibility properties of these scaffolds were investigated. The composite gels were shown to be suitable for 3D printing. In vitro cell culture showed that osteoblasts can adhere and proliferate on the surface of the hydrogel, indicating that the GelMA-SrHA hydrogel has good cell viability and biocompatibility. The GelMA-SrHA composites are promising 3D-printed scaffolds for bone repair.

This study reports the preparation and characterization of Polybutylene Succinate (PBS)-Polycaprolactone (PCL) melt blends (10–40 wt.% PCL) in the presence of a compatibilizer, in order to explore their potential use as a biomaterial. The thermal transitions, as well as the crystallinity of the polymer blends were analyzed by Differential Scanning Calorimetry, the thermomechanical properties were analyzed via Dynamic Mechanical Analysis and phase morphologies were characterized by Scanning Electron Microscopy. Degradation profiles of the blends were analyzed in PBS buffer solution at pH 7.4 at 37°C via pH measurements. Cytotoxicity of the PBS/PCL films were tested by MTS assay.

Tympanic membrane (TM) perforations, primarily induced by middle ear infections, the introduction of foreign objects into the ear, and acoustic trauma, lead to hearing abnormalities and ear infections. We describe the design and fabrication of a novel composite patch containing photocrosslinkable gelatin methacryloyl (GelMA) and keratin methacryloyl (KerMA) hydrogels. GelMA-KerMA patches containing conical microneedles in their design were developed using the digital light processing (DLP) 3D printing approach. Following this, the patches were biofunctionalized by applying a coaxial coating with PVA nanoparticles loaded with gentamicin (GEN) and fibroblast growth factor (FGF-2) with the Electrohydrodynamic Atomization (EHDA) method. The developed nanoparticle-coated 3D-printed patches were evaluated in terms of their chemical, morphological, mechanical, swelling, and degradation behavior. In addition, the GEN and FGF-2 release profiles, antimicrobial properties, and biocompatibility of the patches were examined in vitro. The morphological assessment verified the successful fabrication and nanoparticle coating of the 3D-printed GelMA-KerMA patches. The outcomes of antibacterial tests demonstrated that GEN@PVA/GelMA-KerMA patches exhibited substantial antibacterial efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, cell culture studies revealed that GelMA-KerMA patches were biocompatible with human adipose-derived mesenchymal stem cells (hADMSC) and supported cell attachment and proliferation without any cytotoxicity. These findings indicated that biofunctional 3D-printed GelMA-KerMA patches have the potential to be a promising therapeutic approach for addressing TM perforations.

In this study, fibrous scaffolds based on poly(γ-benzyl-l-glutamate) (PBLG) were investigated in terms of the chondrogenic differentiation potential of human tooth germ stem cells (HTGSCs). Through the solution-assisted bonding of the fibres, fully connected scaffolds with pore sizes in the range 20–400 µm were prepared. Biomimetic modification of the PBLG scaffolds was achieved by a two-step reaction procedure: first, aminolysis of the PBLG fibres’ surface layers was performed, which resulted in an increase in the hydrophilicity of the fibrous scaffolds after the introduction of N⁵-hydroxyethyl-l-glutamine units; and second, modification with the short peptide sequence azidopentanoyl–GGGRGDSGGGY–NH₂, using the 'click' reaction on the previously modified scaffold with 2-propynyl side-chains, was performed. Radio-assay of the ¹²⁵I-labelled peptide was used to evaluate the RGD density in the fibrous scaffolds (which varied in the range 10^–3–10 pm/cm²). All the PBLG scaffolds, especially with density 90 ± 20 fm/cm² and 200 ± 100 fm/cm² RGD, were found to be potentially suitable for growth and chondrogenic differentiation of HTGSCs. Copyright © 2015 John Wiley & Sons, Ltd.