Prakash Sojitra¹*, Chhaya Engineer¹, Ankur Raval¹, Devesh Kothwala¹, Arpit Jariwala¹, Haresh Kotadia¹, Subodh Adeshara¹ and Girish Mehta²

Smooth surface is prerequisite for all implantable medical devices to increase biocompatibility. Electropolishing is an effective process for improving surface smoothness of the cardiovascular devices. In this study, electropolishing was employed on laser cut L605 Co-Cr alloy cardiovascular stents to increase surface smoothness. Acid descaling was used as a pretreatment before electropolishing for effective removal of metal oxides generated due to laser-cutting process. Effect of temperature during electropolishing on the rate of material removal was also evaluated. Passivation was carried out after electropolishing of stent to enhance its corrosion resistance in biological environment. The stent was characterized by Optical Microscopy for strut dimension analysis, Scanning Electron Microscopy and Atomic Force Microscopy for its surface smoothness, gravimetric analysis for evaluation of material removal uniformity, EDAX analysis for elemental composition and balloon expandability. It was found that elemental composition of stent remains unaltered after series of chemical treatments including the acid descaling and the electropolishing. Surface roughness of stent after electropolishing was reduced to significant level and such electropolished stents also demonstrated uniform expansion under specific required conditions. 

The present study was carried out to evaluate the in-vitro biocompatibility of cellular and acellular bovine pericardium crosslinked with gluatraldehyde (GA), formadehdye (FA) and 1- ethyl- 3 - (3 - dimethylaminopropyl) carbodiimide (EDC). Pericardium procured from abattoir was divided into to equal halves. One part was crosslinked as such while another part was made acellular and then crosslinked. In-vitro studies included the gross observations, enzymatic degradation (collagenase, elastase and trypsin), free amino group contents determination, moisture percent analysis, SDS-PAGE analysis and in-vitro cell cytotoxicity examination in peripheral blood mononuclear cell (PBMC). GA treatment showed highest resistance to enzymatic degradation and significant reduction (P<0.01) of moisture percentage and free amino acid groups content. SDS-PAGE analysis revealed that GA treated cellular and acellular pericardium expressed highest crosslinking, followed by FA and EDC treated tissues. The stimulation index (SI) revealed that all the biomaterials when used with ConA showed moderate suppression of blastogenic effect of ConA, while suppression was greater when biomaterial was used alone without ConA. 

Commercial pure titanium (cpTi) sheets were subjected to various chemical treatments to study the role of surface chemistry, morphology etc., on improving the bioactivity, the ability to form hydroxyapatite (HA) coating in simulated body fluid (SBF). Both the treated and untreated samples were characterized before and after immersing in SBF by X-ray powder diffraction, scanning electron microscopy and atomic force microscopy techniques. The combination of acid plus alkali treatment seems to nucleate more and dense HA compared to other treatments. The HA nucleates initially along the grain boundaries and then homogenously with immersion time. The overall effect of grain boundary and roughness leading to the formation of higher amount of sodium titanate gel has been proposed for the bioactivity enhancement of cpTi by the proposed surface treatment. 

Durgadas CV¹, Kaladhar K^1#, Divya P¹, Sreenivasan K², Sharma CP¹*

Here we report the blood compatibility and Langmuir monolayer stability at air water interface of gold nanoparticles (GNPs) synthesized using o,o’ bis (2 amino propyl) poly ethylene glycol (M. Wt. 1900) (DAPEG) as capping agent by a one pot synthetic approach. PEGylated GNPs were synthesized with varying concentration of DAPEG using Sodium Borohydride (SBH) as a reducing agent, at room temperature. The NPs were characterized by HRTEM, Dynamic Light Scattering and UV/ Vis absorption spectroscopy. The blood compatibility of the nanoparticles in activating the blood components was investigated by haemolysis assay and platelet activation studies. Our preliminary results show that modified gold nanoparticles are more blood compatible and stabilize the lipid monolayer reflecting the possibility of tuning new hybrid materials.

#Present address: Division of Chemcal and Petroleoum Engineering, Bioengineering, Immunology, Swanson School of Engineering, The McGowan Institute for Regenerative Medicine, University of Pittsburg, Pittsburg, PA, USA

Ige, O.O.¹, Umoru, L.E.², Adeoye, M.O.², Adetunji, A.R.^2,3, Olorunniwo, O.E.² and Akomolafe, I.I.¹