Effect of photografting 2-hydroxyethyl acrylate on the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) fibroporous mats

Effect of membrane parameters and filter structure on the efficiency of leukocyte removal by electrospun poly(ethylene-co-vinyl alcohol) membranes

Electrospinning technology is an experimentally verified tool for the generation of membranes with competing efficiency useful for leukodepletion filter, customarily used in blood banks to lessen the risks with blood transfusions. Even though a few electrospun polymers have been reported to be efficient leukodepletion filter membranes, poly(ethylene-co-vinyl alcohol) (EVAL) being one among, owe to their exceptional advantage of being electrospun from a non-toxic solvent like rubbing alcohol. Besides their excellent blood compatibility, EVAL membranes proffer a leukodepletion performance nearly as same as that of commercial leukodepletion filters. However, the role of various membrane parameters on the leukodepletion efficiency of electrospun EVAL membranes need to be disclosed in advance to their commercialization. Hence this study is an attempt to disclose the ability of electrospinning to being tuned towards the fabrication of filters with different membrane parameters including fiber diameter and pore diameter, with a typical example of EVAL. In addition, the impact of filter design upon the leukodepletion performance was also unveiled by comparing a symmetric filter where all the membranes were of uniform pores with that of an asymmetric filter where the pore sizes of upper and lower layer in the filter was different. The results of blood filtration experiments through the developed prototype filters underline the superiority of asymmetric filters over to symmetric one and, the asymmetric filters wherever the fiber diameter was 1.8 and 3 μm, offered rapid and excellent leukodepletion. Membranes with thinner fibers showed an increased flow resistance. The pore sizes of the membranes being 9 - 29 μm, larger than the size of blood cells, alludes to the direct adhesion of leukocytes to filter membranes as the major mechanism of leukocyte removal. Hence it is concluded that despite the suitability of electrospinning for fabrication of leukodepletion filter media, the use of nano-dimension fibers is not preferred for leukocyte adhesion filter when the material of choice is such a polymer with ideal surface chemistry, wettability and inherent ability for leukocyte binding.

A Patterned Butyl Methacrylate-co-2-Hydroxyethyl Acrylate Copolymer with Softening Surface and Swelling Capacity

The tunable swelling and mechanical properties of nanostructures polymers are crucial parameters for the creation of adaptive devices to be used in diverse fields, such as drug delivery, nanomedicine, and tissue engineering. We present the use of anodic aluminum oxide templates as a nanoreactor to copolymerize butyl methacrylate and 2-hydroxyethyl acrylate under radical conditions. The copolymer obtained under confinement showed significant differences with respect to the same copolymer obtained in bulk conditions. Molecular weights, molecular weight dispersities, Young's modulus, and wetting behaviors were significantly modified. The combination of selected monomers allowed us to obtain nanopillar structures with an interesting softening surface and extraordinary swelling capacity that could be of special interest to surface science and specifically, cell culture.

Differential Adhesive and Bioactive Properties of the Polymeric Surface Coated with Graphene Oxide Thin Film

Surface engineering of implantable devices involving polymeric biomaterials has become an essential aspect for medical implants. A surface enhancement technique can provide an array of unique surface properties that improve its biocompatibility and functionality as an implant. Polyurethane-based implants that have found extensively acclaimed usage as an implant in biomedical applications, especially in the area of cardiovascular devices, still lack any mechanism to ward off bacterial or platelet adhesion. To bring out such a defense mechanism we are proposing a surface modification technique. Graphene oxide (GO) in very thin film form was wrapped onto the electrospun fibroporous polycarbonate urethane (PCU) membrane (GOPCU) by a simple method of electrospraying. In the present study, we have developed a simple single-step method for coating a polymeric substrate with a thin GO film and evaluated the novel antiadhesive activity of these films. SEM micrographs after coating showed the presence of very thin GO films over the PCU membrane. On the GOPCU surface, the contact angle was shifted by ∼30°, making the hydrophobic PCU surface slightly hydrophilic, while Raman spectral characterization and mapping showed the presence and distribution of GO over 75% of the membrane. A reduced platelet adhesion on the GOPCU surface was observed; meanwhile, bacterial adhesion also got reduced by 85% for Staphylococcus aureus (Gram positive, cocci) and 64% for Pseudomonas aeruginosa (Gram negative, bacilli). A cell adhesion study conducted using mammalian fibroblast cells projected its proliferation percentage in a MTT assay, with 82% cell survival on PCU and 86% on GOPCU after 24 h culture, while a study for an extended period of 72 h showed 87% of survival on PCU and 88% on GOPCU. This plethora of functionalities by a simple modification technique makes thin GO films a self-sufficient surface engineering material for future biomedical applications.