A cysteine-containing elastin-like polypeptide (ELP2cys) was successfully synthesized and purified, and was shown to behave in a similar fashion to other well-characterized ELPs. Incorporating the ELP2cys as a crosslinking agent into a solution of sulphated hyaluronan (CMHA-S) not only decreased the gelation time of the solution but also increased the crosslinking density of the resultant hydrogel, in turn increasing both the resiliency and stiffness of the construct. Preliminary in vitro work involved culture of human disc cells, followed by their encapsulation within the hydrogel. Unfortunately the results were inconclusive, although it appeared as though the addition of ELP2cys to the matrix did not negatively affect the viability of the cells, as compared to hydrogels with CMHA-S only. This study showed that ELP2cys is a valuable addition to the family of recombinant elastin-like polypeptides, and shows promise as a crosslinking agent in the formation of hyaluronan hydrogels.

A cysteine-containing elastin-like polypeptide (ELP2cys) was successfully synthesized and purified, and was shown to behave in a similar fashion to other well-characterized ELPs. Incorporating the ELP2cys as a crosslinking agent into a solution of sulphated hyaluronan (CMHA-S) not only decreased the gelation time of the solution but also increased the crosslinking density of the resultant hydrogel, in turn increasing both the resiliency and stiffness of the construct. Preliminary in vitro work involved culture of human disc cells, followed by their encapsulation within the hydrogel. Unfortunately the results were inconclusive, although it appeared as though the addition of ELP2cys to the matrix did not negatively affect the viability of the cells, as compared to hydrogels with CMHA-S only. This study showed that ELP2cys is a valuable addition to the family of recombinant elastin-like polypeptides, and shows promise as a crosslinking agent in the formation of hyaluronan hydrogels.

This Master‘s thesis is focused on the preparation of hydrogels based on a hydrophobic derivative of hyaluronic acid palmitoyl hyaluronan in presence of biosurfactant decyl glucoside’s micelles and micelles of surfactant triton X-100. For followed characterization were chosen rheological tests and infrared spectrometry. There was observed influence of preparation method, type and concentration of surfactant and presence of micelles on final features of the hydrogel. Moreover, an experimental test of swelling was performed with interesting results for future research.

The present work addresses poor bone/implant integration and severe bone defects. In both conditions external stimuli is required for new bone to form. A multilayered functional implant coating, comprised of an inner layer of crystalline titanium dioxide (TiO2) and an outer layer of hydroxyapatite (HAP), loaded with bone morphogenetic protein-2 (BMP-2), was proposed as a tool for providing both improved initial bone formation and long-term osseointegration. The in vitro characterization of the implant coatings showed that TiO2 and HAP were more favorable for cell viability, cell morphology and initial cell differentiation, compared to native titanium oxide. Furthermore, significantly higher cell differentiation was observed on surfaces with BMP-2, indicating that a simple soaking process can be used for incorporating bioactive molecules. Moreover, the results suggest that there could be a direct interaction between BMP-2 and HAP, which prolongs the retention of the growth factor, improving its therapeutic effect. For treating severe bone defects a strategy involving BMP-2 delivery from hyaluronan hydrogels was explored. The hydrogels were prepared from two reactive polymers – an aldehyde-modified hyaluronan and a hydrazide-modified poly(vinyl alcohol). Upon mixing, the two components formed a chemically crosslinked hydrogel. In this work the mixing of the hydrogel components was optimized by rheological measurements. Furthermore, an appropriate buffer was selected for in vitro experiments by studying the swelling of hydrogels in PBS and in cell culture medium. A detection method, based on radioactive labeling of BMP-2 with 125I was used to monitor growth factor release both in vitro and in vivo. The results showed a biphasic release profile of BMP-2, where approximately 16 %  and 3 % of the growth factor remained inside the hydrogel after 4 weeks in vitro and in vivo, respectively. The initial fast release phase corresponded to the early ectopic bone formation observed 8 d after injection of the hydrogel formulation in the thigh muscle of rats. The hydrogel formulation could be improved by incorporation of HAP powder into the hydrogel formulation. Furthermore, bone formation could be increased by pre-incubation of the premixed hydrogel components inside the syringe prior to injection. Crushed hydrogels were also observed to induce more bone formation compared to solid hydrogels, when implanted subcutaneously in rats. This was thought to be due to increased surface area of the hydrogel, which allowed for improved cell infiltration.