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This research investigates the optical and biocompatible properties of alkali-treated cpTi immersed in aspirin and different molecular weights of polyethylene (PEG). Instrumental characterizations were performed using scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet–visible spectroscopy. Additionally, drug release, antithrombotic, and cell adhesion studies were conducted in in-vitro conditions. The SEM micrographs showed that heat treatment of NaOH modified cpTi substrates increased the average surface pore size by 217%. Raman spectra’s active modes confirmed the presence of titanate groups which intensified the semiconductive nature of alkali-treated cpTi substrates. Further, the semiconductive nature was confirmed through the shift of the energy bandgap from 2.69 to 2.9 eV. The continuous redshift of the absorbance edge with an increase in the molecular weight of PEG indicates improved optical property. Following the Rigter–Peppas dynamic model, the drug release kinetics showed a non-Fickian dispersion (n < 1) and super case II transport (n = 2.21) for PEG-coated cpTi substrates. The alkali-treated cpTi-aspirin-PEG surface exhibits suitable antithrombotic property and interstitial cell adhesion with PEG coating. The modified surface on cpTi demonstrated a promising technique to improve the optical, antithrombotic, and biocompatibility performances, which are the prime requirement for the blood-interacted cardiovascular devices such as stents.

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The present work describes the inhibition studies of free as well as immobilized urease by different heavy metals. Porous silicon (PS) films prepared by electrochemical etching were used for urease immobilization by physical adsorption. The enzyme was subjected to varying concentrations of Cr 6+ , Cr 3+ , Cu 2+ , Fe 2+ , Cd 2+ and Ni 2+ and analyzed for the variation in the activity. To study the effect of other heavy metals on the interaction of urease and Cr 6+ , free as well as immobilized urease was subjected to the combination of each metal ion with Cr 6+. Results proved the sensitivity of free as well as immobilized urease towards heavy metals by observed reduction in activity. Immobilized urease showed less degree of inhibition compared to free urease when tested for inhibition by individual metal ions and in combination with Cr 6+. IC 50 values were found higher for inhibition by the combination of metal ions with Cr 6+. Interaction of heavy metal ions with functional groups in active site of urease and limitations of mass transfer are the two factors responsible for the variation in activity of urease. Relation between the variation of urease activity and amount of heavy metals can be applied in biosensor development for determining the concentration of Cr 6+ present in the water samples.

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