The promising potential of a RAD‐16 self‐assembly‐peptide hydrogel as a scaffold for tissue‐engineered cartilage was investigated. Within 3 weeks of in vitro culture, chondrocytes within the hydrogel produced a high amount of GAG and type‐II collagen, which are the components of cartilage‐specific extracellular matrix (ECM). With the culture time increased, toluidine‐blue staining for GAG and immuno‐histochemistry staining for type‐II collagen of the chondrocytes‐hydrogel composites became more intense. Analysis of the gene expression of the ECM molecules also confirmed the chondrocytes in the peptide hydrogel maintained their phenotype within 3 weeks of in vitro culture.
A mathematical model is described for surface‐initiated photopolymerization of PEG‐DA forming crosslinked biofunctional PEG hydrogel membranes based on the NF technique. The model includes an additional monomer with biological functionality, which is a common experimental strategy for the design of ECM mimics in tissue engineering in order to direct signaling pathways, and considers concentration‐dependent VP propagation and reaction diffusion termination. The influence of these features on the crosslink density of the soluble and gel phases, the progression through gelation, sol/gel fraction, and molecular weight distribution of biofunctional PEG hydrogel are studied using the NF model. This model may be useful for specific applications of tissue engineering.
Alkaline phosphatase (ALP), an enzyme involved in mineralization of bone, is incorporated into three hydrogel biomaterials to induce their mineralization with calcium phosphate (CaP). These are collagen type I, a mussel‐protein‐inspired adhesive consisting of PEG substituted with catechol groups, cPEG, and the PEG/fumaric acid copolymer OPF. After incubation in Ca‐GP solution, FTIR, EDS, SEM, XRD, SAED, ICP‐OES, and von Kossa staining confirm CaP formation. The amount of mineral formed decreases in the order cPEG > collagen > OPF. The mineral:polymer ratio decreases in the order collagen > cPEG > OPF. Mineralization increases Young's modulus, most profoundly for cPEG. Such enzymatically mineralized hydrogel/CaP composites may find application as bone regeneration materials.
A simplified steady‐state model to predict MWDs of ethylene/butene and ethylene/hexene copolymers produced industrially using heterogeneous Z‐N catalysts is developed. Estimability analysis is used to guide model simplification and to determine which parameters can be estimated using the available data. Scaling of response variables and parameters using information about their uncertainties ensures that appropriate results are obtained from the estimability analysis. Parameter estimates are obtained to provide good predictions of the measured MWDs. Although the parameter values obtained are specific to the Z‐N catalyst of our industrial sponsor, the method should be useful for parameter estimation and model simplification in other catalytic polymerization systems.
