Faculty Publications
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Item Probing the influence of strontium doping and annealing temperature on the structure and biocompatibility of hydroxyapatite nanorods(Royal Society of Chemistry, 2024) Patil, H.G.; Rajendran, A.; Lenka, N.; Kumar, B.S.; Murugesan, S.; Anandhan, S.Among numerous biologically important metal cations, strontium (Sr2+) has received much attention in bone tissue regeneration because of its osteoinductive properties combined with its ability to inhibit osteoclast activity. In this study, strontium-doped hydroxyapatite (Sr-HAp) nanorods with varying molar ratios of Ca : Sr (10 : 0, 9 : 1, 5 : 5, 3 : 7 and 0 : 10) were synthesized using the chemical precipitation technique. The synthesized Sr-HAp nanostructures were characterized using powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy, energy dispersive X-ray spectroscopy, and Raman and Fourier transform infrared (FTIR) spectroscopies to understand their structural and morphological features, and composition. XRD results revealed the formation of HAp nanostructures, whose unit cell volume increased as a function of the dopant level. The reaction process investigation showed the formation of hydroxyapatite (HAp), strontium apatite (SAp) and various Sr-HAp phases. FESEM micrographs displayed the morphological transformation of Sr-HAp from nanorods to nanosheets upon increasing the dopant level. In the FTIR spectra, the bands of the PO43− group shifted towards a lower wavenumber upon increasing the dopant concentration in Sr-HAp that signifies the structural distortion due to the presence of a large amount of strontium ions. The peaks of PO43− and OH− vibrations in the Raman spectra were further analysed to corroborate the structural distortion of Sr-HAp. Selected area electron diffraction patterns obtained using TEM reveal the reduced crystallinity of Sr-HAp due to Sr-doping, which is in line with the XRD results. Finally, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that the synthesized Sr-HAp has no toxic effect on the survival and growth of mesenchymal stem cells. In summary, the synthesized novel Sr-HAp nanorods exhibit great promise for bone tissue engineering applications. © 2024 The Royal Society of Chemistry.Item Development of electrospun scaffolds for bone regeneration from strontium-doped hydroxyapatite nanorods and thermoplastic polyurethane elastomer(Elsevier Ltd, 2025) Murugesan, S.; Patil, H.G.; Deshmukh, B.K.; N, S.; Asokan, A.; Mohapatra, A.; Lenka, N.; Anandhan, S.Strontium based biomaterials have gained importance in bone tissue regeneration due to their incredible osteoinductivity and differentiation ability. In this study, strontium-doped hydroxyapatite nanorods [SrHAp, Ca9Sr(PO4)6(OH)2] were synthesized by the coprecipitation method. Subsequently, electrospun fibrous scaffolds were fabricated from thermoplastic polyurethane elastomer (TPU) dispersed with SrHAp nanorods. The loading of SrHAp nanorods in TPU was varied from 1 wt% to 7 wt% in steps of 2. Morphology of electrospun fibrous scaffolds and the dispersion of nanorods in the TPU matrix were characterised by field emission scanning electron microscopy, and elemental mapping by energy-dispersive x-ray spectroscopy, respectively. The scaffolds exhibited 3D interconnected network structure with well-distributed pores. The SrHAp nanorods were observed to be smoothly dispersed in the polymer matrix in the scaffolds using elemental mapping and transmission electron microscopy. The newly developed scaffolds exhibited adequate mechanical strength combined with good biocompatibility and excellent biomineralization characteristics. Further, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay of the electrospun scaffolds against gingiva-derived mesenchymal stem cells (gMSCs) revealed excellent survival and growth rate of the cells. In addition, the osteoinductivity study using gMSCs confirms the better osteodifferentiation in the scaffold containing 5 wt% SrHAp compared with its counterparts by showing the expressions of alkaline phosphatase (ALP), osteocalcin (OCN) and RUNX2. Among all the compositions, the one with 3 wt% SrHAp loading demonstrated promising results in terms of fiber uniformity, improved mechanical properties, and enhanced cell viability. Thus, the SrHAp/TPU scaffolds developed in this study have the potential for use in bone tissue regeneration. © 2025 Elsevier LtdItem Biomimetic Engineering of Robust Gradient Antibacterial Coatings using Hollow Nanoframes of Prussian Blue Analogues(John Wiley and Sons Inc, 2025) He, X.; Wu, H.; Xu, K.; Tang, J.; Li, C.; Gnanasekar, G.; Rao, X.; Murugesan, S.; Barão, V.A.R.; Kang, E.-T.; Xu, L.Photothermal therapy for bacterial infections poses a significant challenge due to the high temperatures required for effective bacterial eradication, which can also harm surrounding healthy tissues. Determining the minimal effective temperature for bacterial destruction is therefore critical. In this study, artificial reef-like manganese-doped Prussian blue (PBMn) nanoframes are developed as photothermal agents and physical cross-linkers to reinforce a phytic acid and cationic polymer network coating. This innovative deposition approach facilitates the creation of a gradient PBMn-enhanced phytic acid-cationic polymer (PC-PBM) coating, achieving a balance between effective photothermal antibacterial activity and reduced heat-induced collateral damage. When applied to a polyurethane (PU) substrate, the gradient PC-PBM coating exhibits excellent photothermal efficiency, biocompatibility, and tunable antibacterial activity. Gene transcriptomics analysis demonstrates significant downregulation of virulence genes and biofilm-forming genes in pathogens following PC-PBM treatment, confirming the antibacterial efficacy of the coating. Both in vitro and in vivo evaluations, including studies in an infected hernia model, underscore the coating's excellent anti-infection performance. This work introduces a robust and biomimetic strategy for constructing gradient coating, advancing photothermal therapy by achieving effective bacterial eradication with reducing collateral damage to healthy tissues. © 2025 Wiley-VCH GmbH.Item Amyloid-like Protein-Metal Sulfide Nanocoatings for Synergistic Photothermal and Antibacterial Implant Surface Protection(American Chemical Society, 2025) Li, K.; Zhang, X.; Xu, L.; Xu, K.; Rao, X.; Murugesan, S.; Barão, V.A.R.; Yang, P.; Kang, E.-T.Preventing bacterial adhesion and biofilm formation is essential for the long-term success of biomedical implants. Implant-associated infections remain a significant clinical challenge, underscoring the urgent need for effective and durable antimicrobial surface strategies. This study develops a nanocoating with dual antibacterial adhesion and photothermal antibacterial properties for biomedical surface modification. Bovine serum albumin-templated metal sulfide (MS@BSA) nanocomposites are synthesized and converted into a stable nanofilm via phase-transitioned BSA (PTB) self-assembly. The MS@PTB coating adheres to various substrates and demonstrates broad-spectrum antibacterial activity. In vitro assays show that the copper sulfide@PTB (CuS@PTB) coating significantly reduces bacterial attachment and suppresses biofilm development upon 808 nm near-infrared irradiation. RNA sequencing identifies differentially expressed genes in common pathogens, indicating disrupted respiration, energy metabolism, and virulence pathways as well as stress responses to heat and copper ions. In vivo experiments using rat subcutaneous infection and abdominal wall defect models demonstrate that CuS@PTB markedly reduces bacterial load and inflammatory responses while accelerating tissue regeneration and maintaining excellent biocompatibility. The results demonstrate the synergistic antibacterial effects of photothermal heating and Cu ion release, supporting CuS@PTB as a promising antimicrobial surface coating for implantable biomaterials. © 2025 American Chemical Society