Faculty Publications
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Publications by NITK Faculty
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Item Biological and Physical Characterization of Surface-Modified Grade v Titanium Alloy(Hindawi Limited, 2024) Kakunje, M.; Nambiar, S.; Isloor, A.M.; Kabekkodu, S.; Bhat K, U.Surface modification and biomimetic approaches have been widely used to enhance bioinert substances. It is not very clear whether surface alterations and polymer coatings on titanium make it more biologically active and enhance cell adhesion. We tried to focus on the physical and biological characterization of surface-modified titanium disks. Four different surface modifications were done for the titanium disks, ranging from acid etching, sandblasting, polydopamine coating, and polydopamine-based chitosan coating, and were compared with disks without any surface modification. The disks were studied for physical characteristics like surface roughness and contact angle. Human gingival fibroblasts were used to investigate the biological effects of surface modification of titanium alloy surfaces. The wettability of chitosan-coated, acid-etched, and polydopamine-coated titanium was much better than that of the sandblasted surface, indicating that surface energy was higher for acid-etched and coated surfaces than others. The cell seeding with fibroblasts showed increased adhesion to the smoother surfaces as compared to the rougher surfaces. Polydopamine coatings on titanium disks showed the most favorable physical and biological properties compared to others and can be a good surface coating for in vivo implants. © 2024 Mahesh Kakunje et al.Item Pyrene carbaldehyde derived carbon dots for detecting water in alcohol and security printing(Elsevier B.V., 2024) Ullal, N.; Sahoo, B.; Dhanya, D.; Kulkarni, S.D.; Bhat K, U.; AnandThis study focuses on preparing Carbon dots (CDs) from Pyrene-1-carbaldehyde (PCA) using a solvothermal method and further purification using column chromatography. The aggregation-induced emission (AIE) of CDs was systematically investigated in a THF/water medium. The CDs showed red shifts in their photoluminescence (PL) spectra upon increase in water content. Scanning electron microscopic (SEM) images revealed the formation of aggregates, while X-ray diffraction (XRD) confirmed that the d-spacing values remains unchanged. The NMR spectrum of the CDs displayed peaks corresponding to aromatic carbon, which disappeared upon addition of water due to ?-? stacking, indicating aggregate formation. Based on the aggregation-induced fluorescence emission mechanism, detection of water content in alcohol is demonstrated. Moreover, the synthesized CDs were used as fluorescent colorant in screen inks along with polyvinyl alcohol (PVA) and hydroxyethyl cellulose (HEC) as binders. The print proofs obtained on UV-dull paper using PVA-based screen ink exhibited fluorescence emission at longer wavelengths and showcased desirable photostability under prolonged UV exposure compared to the prints obtained using HEC-based ink. Moreover, though the PVA based print appeared blue or cyan fluorescent, the actual yellow emissions from the CDs can be visualised using UV block filter. Such features, masked to the forger, but known to the user can be utilised in checking the authenticity of the print. © 2024 The AuthorsItem Ink formulations using Eu3+ doped strontium aluminates for security printing(Elsevier B.V., 2025) Ullal, N.; Sahoo, B.; Dhanya, D.; Kulkarni, S.D.; Bhat K, U.; P.j, A.; Rao, A.Counterfeiting is a widespread menace that affects multiple sectors of society, which is increasing due to technological advancements and growing globalization of trade. It undermines economic growth, endangers public safety, damages brand integrity, and facilitates criminal activities. The present study focuses on the synthesis of thermally stable europium (Eu3+) doped orthorhombic Sr4All4O25 (SAO) system by solid state method for use as a colorant in the formulation of viz based and polyvinyl alcohol (PVA) based screen inks. The steady state spectrum of Eu3+ doped SAO depicts the charge transfer taking place between host (O2-) and half-filled f-orbital of Eu3+ ion. Mono-exponential decay with lifetime value recorded in milliseconds indicates substitution of single Sr host lattice. The screen prints obtained on UV dull paper using PVA based ink with Eu3+ doped SAO as pigment displayed better photostability and abrasion resistance. Both Viz and PVA based formulations could serve as invisible inks for security printing and information storage applications. The prints produced using the viz-based and PVA-based formulations appeared fluorescent blue under UV illumination, while they exhibited red and green fluorescence, respectively, when viewed through long-pass filters. A user familiar with these features can easily authenticate the prints, whereas replicating them is challenging for counterfeiters. © 2025 The Authors