Scientific advances in biomaterials, stem cells, growth and differentiation factors, and biomimetic environments have created unique opportunities to fabricate or improve existing tissues in the laboratory from combinations of engineered extracellular matrices ("scaffolds"), cells, and biologically active molecules. ĭevelopments in the multidisciplinary field of tissue engineering have yielded a novel set of tissue replacement parts and implementation strategies. A further description goes on to say that an "underlying supposition of tissue engineering is that the employment of natural biology of the system will allow for greater success in developing therapeutic strategies aimed at the replacement, repair, maintenance, or enhancement of tissue function". Tissue engineering has also been defined as "understanding the principles of tissue growth, and applying this to produce functional replacement tissue for clinical use". In addition, Langer and Vacanti also state that there are three main types of tissue engineering: cells, tissue-inducing substances, and a cells + matrix approach (often referred to as a scaffold). Micro-mass cultures of C3H-10T1/2 cells at varied oxygen tensions stained with Alcian blueĪ commonly applied definition of tissue engineering, as stated by Langer and Vacanti, is "an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve function or a whole organ". 9 Constructing neural networks in soft material.6.2.10 Self-assembled recombinant spider silk nanomembranes.6.2.6 Thermally induced phase separation.6.2.3 Solvent casting and particulate leaching.3.3 Modern era (20th and 21st centuries).3.2 Enlightenment (17th century–19th century).Poly(dimethylsiloxane) Poly(ethylene glycol) Salt templating Scaffold Tissue engineering.Ĭopyright © 2019 Acta Materialia Inc. Further, bioactivity and osteoinductivity were simultaneously achieved in human bone marrow-derived MSC culture, representing a notable achievement for an exclusively material-based strategy. We were able to show that these PDMS star-PEG hydrogels maintain several key material characteristics for bone repair. Herein, we have fabricated an interconnected, macroporous PEG-DA hydrogel scaffold that utilizes PDMS star-MA as a bioactive and osteoinductive scaffold component. Typically, glass/ceramic fillers are utilized to achieve this through their ability to induce hydroxyapatite formation ("bioactive") and promote MSC differentiation to an osteoblast-like fate ("osteoinductive"). STATEMENT OF SIGNIFICANCE: A tissue engineering scaffold that can inherently guide mesenchymal stem cells (MSCs) to regenerate bone tissue without growth factors would be a more cost-effective and safe strategy for bone repair. However, all templated SIPS PDMS star-PEG hydrogels were confirmed to be bioactive, non-cytotoxic and displayed PDMS star-MA dose-dependent osteogenesis. Distribution of PDMS star-MA within the PEG-DA matrix improved for the lower M n and contributed to differences in specific material properties (e.g. Tunable, interconnected macropores were achieved by utilization of a fused salt template of a specified salt size during fabrication. Finally, cell culture with seeded human bone marrow-derived MSCs (hBMSCs) was used to confirm non-cytotoxicity and characterize osteoinductivity. mineralization when exposed to simulated body fluid, SBF). The distribution of PDMS star-MA within the hydrogels was examined as well as pore size, percent interconnectivity, dynamic and static moduli, hydration, degradation and in vitro bioactivity (i.e. Scaffolds were prepared with PDMS star-MA of two number average molecular weights (M ns) (2k and 7k) with varying PDMS star-MA:PEG-DA ratios and template salt sizes. Herein, we have combined solvent induced phase separation (SIPS) with a fused salt template to create PDMS star-PEG hydrogel scaffolds with controlled PDMS star-MA distribution as well as interconnected macropores of a tunable size to allow for subsequent cell seeding and neotissue infiltration ("osteoconductive"). Previously, we established that hydrogel scaffolds formed by crosslinking methacrylated star poly(dimethylsiloxane) (PDMS star-MA) with diacrylated poly(ethylene glycol) (PEG-DA) promote bone bonding by induction of hydroxyapatite formation ("bioactive") and promote MSC lineage progression toward osteoblast-like fate ("osteoinductive"). A scaffold that is inherently bioactive, osteoinductive and osteoconductive may guide mesenchymal stem cells (MSCs) to regenerate bone tissue in the absence of exogenous growth factors.
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