A Co-Polymerizable Linker for the Covalent Attachment of Fibronectin Makes pHEMA Hydrogels Cell-Adhesive.

Hydrogels are attractive biomaterials because their chemical and mechanical properties can be tailored to mimic those of biological tissues. However, many hydrogels do not allow cell or protein attachment. Therefore, they are post-synthetically functionalized by adding functional groups for protein binding, which then allows cell adhesion in cell culture substrates. However, the degree of functionalization and covalent binding is difficult to analyze in these cases. Moreover, the density of the functional groups and the homogeneity of their distribution is hard to control. This work introduces another strategy for the biofunctionalization of hydrogels: we synthesized a polymerizable linker that serves as a direct junction between the polymeric structure and cell adhesion proteins. This maleimide-containing, polymerizable bio-linker was copolymerized with non-functionalized monomers to produce a bioactive hydrogel based on poly(2-hydroxyethyl methacrylate) (pHEMA). Therefore, the attachment site was only controlled by the polymerization process and was thus uniformly distributed throughout the hydrogel. In this way, the bio-conjugation by a protein-binding thiol-maleimide Michael-type reaction was possible in the entire hydrogel matrix. This approach enabled a straightforward and highly effective biofunctionalization of pHEMA with the adhesion protein fibronectin. The bioactivity of the materials was demonstrated by the successful adhesion of fibroblast cells.

Volumetric Analysis and Clinical Outcome in 54 Patients with Retrobulbar Hematoma.

PURPOSE: Retrobulbar hematoma (RBH) is a rare but serious vision threatening emergency. We analyze the relationship between hematoma volume, visual impairment and outcome. METHODS: Fifty-four patients with RBH receiving orbital decompression were retrospectively included. Volumetric analysis of RBH was performed by semi-automatic segmentation based on preoperative CT scans using ITK-SNAP software. Best corrected visual acuity (BCVA) measurements were obtained and correlated in 2 groups (no light perception (NLP), severe visual impairment) with the hematoma volume. RESULTS: NLP was documented preoperatively in 5/28 and postoperatively in 9/43 patients. Preoperative NLP was significantly associated with a larger hematoma volume (P = .03) and higher hematoma/orbital volume ratio (P = .03). Postoperative severe visual impairment showed significant associations with a larger hematoma volume (P = .02) as well as higher hematoma/orbital volume ratio (P = .02). CONCLUSION: Eyes with severe visual impairment and large hematoma volumes preoperatively are at high risk of permanent vision loss. Hematoma volume calculation might represent an additional prognostic parameter for visual outcome after RBH.