The goal of tissue engineering is to create bioartificial tissues for the replacement of failed or nonfunctional tissue. Porous tissue-engineered scaffolds may be created through a solvent-casting/porogen-leaching technique. Almost exclusively, sodium chloride (NaCl) is the porogen of choice. Previous studies have demonstrated the importance of porosity and pore size in cell adhesion and tissue development, yet the impact of porogen morphology and the chemical effect of porogen residual has not been fully explored. Poly-L-lactide (PLLA) scaffolds were manufactured by a solvent-casting, particulate-leaching method with either glucose or NaCl porogen in an effort to vary pore characteristics and, subsequently, cell adhesion and tissue development. Porogen influence on scaffold morphology and topography was compared via histological techniques and qualitative surface characteristics. Using an in vitro model, scaffolds were seeded with rat aortic smooth muscle cells (SMCs) and evaluated over a 28-day period. Cell attachment and proliferation were subsequently evaluated. Results indicate that initial SMC attachment is higher for scaffolds manufactured with NaCl rather than glucose. The proliferation of SMCs was higher for scaffolds manufactured with glucose and, by day 28, scaffolds manufactured with glucose supported a higher cell population than those processed using NaCl porogen.

Poly(ester amide) copolymers based on L-lactide (2) and a new depsipeptide (1) were prepared by ring opening polymerization in the presence of Sn(Oct)2 as the catalyst. Variable monomer feed ratios up to 2.3 mol% 1 afforded copolymers containing ester and amido functional groups in the backbone. Lower glass transition temperatures and reduced crystallization kinetics and crystallinity compared to homo-polylactide (PLA) was achieved with low levels of amido incorporation. A reactivity comparison between enchainment of 2 and 1 was determined using in situ infrared spectroscopy. An increase in shear viscosity was observed with the increase of 1 content as determined by rheology studies. Cellular compatibility of the co-polymers was investigated by seeding D1 mouse stem cells onto films and characterizing cell morphology by optical microscopy. Preliminary results indicate that these novel materials exhibit reduced cell attachment compared to PLA and, pending further exploration, may have potential use in biomedical applications.

Tissue engineering is a field of bioengineering that merges fundamentals of medicine, engineering, biological science, and materials science to research and produce replacement tissues or organs. In this article, the basics of tissue engineering are discussed, including the different types of cells and matrices researched and how these components are used separately or together for tissue‐engineering applications. After the principles of tissue engineering are described, the role of tissue engineering in medicine is explored with separate discussions on dermal wound treatment, orthopedics, sports medicine, plastic and reconstructive surgery, neurology, and cardiology. Then, the current status of tissue engineering is investigated, from market products to advanced research and manufacturing applications. The article concludes with an exploration of scientific, regulatory, and commercial challenges that must be overcome in order to advance the field of tissue engineering.

A composite that utilizes the osteoinductivity of demineralized bone matrix (DBM) and the attractive characteristics of polylactide (PL) may be useful as a tissue-engineered bone substitute. The objective of this study was to investigate the potential of a composite system consisting of DBM fragments and PL beads to support the attachment and proliferation of multipotent mouse marrow stromal cells and to provide a structure for the cells' differentiation into the osteoblast lineage. Furthermore, the overarching goal was to provide a preliminary assessment of the DBM/PL cultures in order to facilitate the development of injectable composite DBM/PL systems in the long term. Demineralized bone matrix fragments were produced from bovine femurs and polylactide beads were produced by a single emulsion process. Differential scanning calorimetry and gel-permeation chromatography were used to characterize the PL samples. Multipotent mouse marrow stromal cells were cultured on several different substrate mixtures including 100% DBM, 70% DBM:30% PL, 50% DBM:50% PL and 100% PL. Cells were analyzed using a LIVE/DEAD(®) Viability/Cytotoxicity kit as well as scanning electron microscopy. Lactic acid and glucose levels were measured throughout the study. Osteogenic differentiation of the MSCs was assessed with an alkaline phosphatase activity (ALP) assay and RT-PCR for expression of bone sialoprotein, osteocalcin and runt-related transcription factor 2. All cell types attached more readily to DBM fragments than PL beads resulting in more lactic acid production in the samples containing mostly DBM. The ALP activity and gene expression results indicate that the optimal mixture for the D1 line of multipotent mouse marrow stromal cells differentiation into osteoblasts is 100% PL. However, it is likely that the decreased pH in the DBM containing samples resulted in an environment that was not very conducive for osteogenic differentiation.

Cells are used in bone tissue engineering applications to facilitate new bone formation in implants. Enzymatic digestion and marrow removal by either centrifugal force or syringe are three methods used to isolate the cells for culture, but each technique has benefits and drawbacks. This comparative study evaluated the effects of the three cell isolation techniques on the attachment, proliferation, and mineralization of rat bone cells. Cells were isolated, seeded, and cultured following standard protocols for each isolation method. Quantitative assays to determine metabolic activity, lactic acid production, glucose consumption, and amounts of intracellular protein, alkaline phosphatase activity, and extracellular calcium were performed. In addition, cell morphology and viability were examined qualitatively. The results indicate that the cell isolation method affects the attachment, proliferation, and type of tissue formed by cells cultured under identical conditions.