Phase inversion cellulose acetate propionate membranes showed lowpermeability to hydrogen peroxide aqueous solutions. Their permeability wasincreased by alkaline hydrolysis of the ester linking units. However, thepermeability remained lower than that of an unsubstituted cellulose membrane.The inclusion of hydroxypropyl cellulose in the membrane formulation, followedby an alkaline hydrolysis step, increased permeability to hydrogen peroxideaqueous solutions to 29% of that of an unsubstituted cellulose membrane.

Mixed self-assembled monolayers (SAMs) composed of a medium length, reactive, n-organothiol (11-mercaptoundecanoic acid) and a short length, unreactive, hydrophobic n-alkylthiol (7-heptanethiol) chemisorbed onto evaporated gold surfaces, were used to study the effect of the microenvironment on the structure and activity of immobilized glucose oxidase (GOX). The mixed SAMs were characterized by X-ray photoelectron spectroscopy, contact angle measurements, and cyclic voltammetry. The derivatization of the SAMs for the covalent attachment and the immobilized enzyme were studied by X-ray photoelectron spectroscopy. Quantitative analysis of the amide I band of the infrared spectra of GOX immobilized onto surfaces at the two attainable extremes of the hydrophilicity range available to us indicated that the percentage of β sheet increased with increasing hydrophilicity of the microenvironment. The specific activity of GOX was higher when the enzyme was immobilized onto the hydrophobic microenvironment.

Endophthalmitis, an inflammation of the eye due to perioperative infection, may occur after cataract surgery. Intraocular lenses (IOLs) loaded with an antibiotic have been proposed as an alternative to the conventional postoperative endophthalmitis prophylaxis, since the antibiotic is delivered directly to the target site. In this work, an IOL-based antibiotic releasing system was prepared from a copolymer used in the production of IOLs and a fluoroquinolone used in endophthalmitis prophylaxis (moxifloxacin, MFX). Argon plasma-assisted grafting with 2- hydroxyethyl methacrylate (HEMA) in the presence of MFX was the approach selected for surface modification, with MFX loaded both by entrapment in the grafted polyHEMA coating and by soaking. Surface and bulk properties were evaluated before and after surface modification and the MFX release profiles were obtained both in batch mode (sink conditions) and under hydrodynamic conditions, employing a purpose-built microfluidic cell, which simulated the hydrodynamic conditions around the eye lens. The effect of storage on the release profile of the best system was also assessed. The best system released MFX for ca. 15 days above the minimum inhibitory concentration for Staphylococcus aureus and Staphylococcus epidermidis. The released MFX showed antimicrobial activity against these bacteria and was non-cytotoxic against corneal endothelial cells.