Inhibition of Staphylococcus Epidermidis Colonization with Fusidic Acid-Impregnated Catheters

The aim of this study was the preparation and characterization of fusidic acid-impregnated peripheral catheters. In the first part of the study, in vitro drug release studies were performed, and the effect of fusidic acid impregnation on adherence of slime positive Staphylococcus epidermidis to catheters was evaluated as in vitro studies. Fusidic acid-impregnated and naïve catheters were incubated with 108 colony forming unit/mL (cfu/mL) slime positive S. epidermidis during the in vitro experiment. After incubation for 2, 4, 6, 8, 12, 24, 48, and 72 h, the number of colonies were determined in an aliquot and adhered to the catheter. During the in vivo experiment, contaminated naïve and fusidic acid-impregnated catheters ( n = 10 rats in both groups) were implanted subcutaneously in the back of the rats. Rats were killed at the end of the seventh day and catheters were removed. Microbiologic assessments from the explanted catheter segments were performed. Fusidic acid impregnation decreased the number of adherent bacteria to the catheters and the number of free bacteria within the liquid medium significantly. There were 3 positive catheter cultures out of 10 in rats implanted with fusidic acid-impregnated catheters, whereas all explanted catheters from naïve group yielded bacterial growth. The mean cfu counts were significantly less in the fusidic acid-impregnated catheter group. In vitro release studies and antibacterial activity studies correlated well. Additionally, morphological evaluations by scanning electron microscopy showed that fewer bacteria were evident on the fusidic acid-impregnated catheters compared with naïve catheters. As a conclusion, catheter impregnation with fusidic acid is effective in preventing colonization in these in vitro and in vivo sets of experiments, with slime-producing S. epidermidis.

Perspectives on: Materials Aspects for Retinal Prostheses

Retinitis pigmentosa and age-related macular degeneration are both incurable eye diseases that lead to blindness due to photoreceptor degeneration. Electrically stimulating the remaining intact nerve cells may generate some useful vision for patients afflicted with these diseases. Various types of retinal prostheses, sub- and epi-retinal electrode arrays, as well as subretinal microphotodiode arrays are considered from a materials and biocompatibility point of view. Other, more innovative approaches to restoring vision, such as microfluidic pumps and activated nanosystems that deliver neurotransmitters in a controlled way and photodynamic therapy are being developed. This article discusses materials aspects of retinal prostheses that are currently in use or under development.

Microwave-assisted Preparation of Magnetic Albumin Microspheres

A new microwave-assisted method was used to prepare magnetic Fe3 O4 particles and magnetic bovine albumin microspheres. The microwave method produced smaller particles and is faster than traditional methods. The optimum conditions to prepare the Fe3O4 particles were three minutes at pH 13 and 80°C. Magnetic microspheres containing albumin were synthesized based on heating times and temperatures to form microspheres with different properties. For example, heating for 4min, at 160°C, yielded smaller sized microspheres (30 μm). Confirmed by XRD, SEM, and FT-IR that iron oxide particles were encapsulated in biocompatible proteins, The thermal stability of the microspheres were determined by DSC and TG. The magnetic properties were determined by UV—VIS spectraphotometry and a Guoy magnetic balance. This microwave process could become a preferred method for the synthesis of magnetized protein microspheres.