Synthesis and characterization of polypyrrole-hyaluronic acid composite biomaterials for tissue engineering applications.

New tissue engineering technologies will rely on biomaterials that physically support tissue growth and stimulate specific cell functions. The goal of this study was to create a biomaterial that combines inherent biological properties which can specifically trigger desired cellular responses (e.g., angiogenesis) with electrical properties which have been shown to improve the regeneration of several tissues including bone and nerve. To this end, composites of the biologically active polysaccharide hyaluronic acid (HA) and the electrically conducting polymer polypyrrole (PP) were synthesized and characterized. Electrical conductivity of the composite biomaterial (PP/HA) was measured by a four-point probe technique, scanning electron microscopy was used to characterize surface topography, X-ray photoelectron spectroscopy and reflectance infrared spectroscopy were used to evaluate surface and bulk chemistry, and an assay with biotinylated hyaluronic acid binding protein was used to determine surface HA content. PP/HA materials were also evaluated for in vitro cell compatibility and tissue response in rats. Smooth, conductive, HA-containing PP films were produced; these films retained HA on their surfaces for several days in vitro and promoted vascularization in vivo. PP/HA composite biomaterials are promising candidates for tissue engineering and wound-healing applications that may benefit from both electrical stimulation and enhanced vascularization.

Manufacture and characterization of poly(alpha-hydroxy ester) thin films as temporary substrates for retinal pigment epithelium cells.

For many disorders of the retinal pigment epithelium (RPE) for which there are no effective treatments, transplantation of RPE cells may provide a viable means of restoring function. Using a solvent casting technique, we have manufactured thin films of poly(L-lactic acid) and poly(DL-lactic-co-glycolic acid) 75:25 and 50:50. Non-porous, flexible films with controlled thickness as thin as 12 +/- 3 microns and reproducible surface morphologies and flexural properties were produced. Fetal human RPE cells were found to attach to these substrates when cultured in vitro. The films made using this technique may provide a means of transplanting allogeneic RPE cells as a therapy for a number of ocular diseases related to RPE dysfunction.

Assessing the diabetic foot: plantar callus and pressure sensation.

The purpose of this study was to explore the relationship between the loss of protective pressure sensation in the foot and the formation of plantar calluses, two well-known precursors of plantar ulceration, in adults with diabetes referred to an outpatient diabetes education program. Pressure sensation testing was performed using Semmes-Weinstein monofilaments. Foot inspection included the identification and measurement of plantar calluses. Using the Wilcoxon Rank Sum test, groups categorized as sensitive (n = 67) and insensitive (n = 35) were compared on callus formation. The groups had equivalent numbers, areas, and thickness of calluses. The high prevalence of calluses in both sensitive and insensitive groups suggests that additional factors such as age-related changes in the foot and routine footwear must be included in risk assessment of the diabetic foot and in consideration of preventive interventions.

Searching for a dean.

The search for a new dean of a collegiate nursing program offers the faculty and administration an opportunity to clarify their understanding and vision of the future. The authors describe how one nursing faculty, through a search committee, clarified its vision of the future in the process of recruiting, selecting, and evaluating candidates for the deanship.