L. Mohan

Bio: L. Mohan is an academic researcher from Toyohashi University of Technology. The author has contributed to research in topics: Corrosion & Dielectric spectroscopy. The author has an hindex of 16, co-authored 43 publications receiving 898 citations. Previous affiliations of L. Mohan include Council of Scientific and Industrial Research & Anna University.

Electrophoretic deposition of nanocomposite (HAp + TiO2) on titanium alloy for biomedical applications

Abstract: This paper reports on the corrosion and scratch behavior of TiO 2 + 50%HAp nanoceramic coated Ti–13Nb–13Zr orthopedic implant alloy. An adherent thin coating was obtained using the electrophoretic deposition (EPD) technique at 30 V and sintering at 850 °C. The microstructure of the coated surfaces was characterized by optical microscopy, AFM, and SEM, and the composition of the coating was examined using EDAX. The functional groups and formed phases analyzed using FT-IR, and XRD. Further, the adhesion strength of the coatings was evaluated using scratch tester and the corrosion behavior of all samples was tested in Simulated Body Fluid (SBF-Hank's solution) using a potentiodynamic polarization studies. The sintered coating exhibited higher adhesion, lower porosity and higher density compared to unsintered samples, and higher corrosion resistance compared to the substrate. However, the corrosion resistance of the unsintered coating was superior to that of the sintered one due to the presence of minimal interconnected porosity.

Suture materials – Current and emerging trends

Abstract: Surgical sutures are used to facilitate closure and healing of surgical- or trauma-induced wounds by upholding tissues together to facilitate healing process. There is a wide range of suture materials for medical purpose and the main types include absorbable and nonabsorbable. Recently, there is a growth in the development of classes of suture materials based on their properties and capabilities to improve tissue approximation and wound closure. This review outlines and discusses the current and emerging trends in suture technology including knotless barbed sutures, antimicrobial sutures, bio-active sutures such as drug-eluting and stem cells seeded sutures, and smart sutures including elastic, and electronic sutures. These newer strategies expand the versatility of sutures from being used as just a physical entity approximating opposing tissues to a more biologically active component enabling delivery of drugs and cells to the desired site with immense application potential in both therapeutics and diagnostics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1544-1559, 2016.

Electrochemical behavior and effect of heat treatment on morphology, crystalline structure of self-organized TiO2 nanotube arrays on Ti-6Al-7Nb for biomedical applications.

Abstract: In the present work, we investigate the formation of self-organized titanium oxide nanotube layers by anodic oxidation on titanium alloy Ti–6Al–7Nb in electrolyte solution containing sulfuric acid and hydrofluoric acid. The anodized surface was characterized by micro-Raman, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS). The corrosion behavior of the treated and untreated samples was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks' solution). The investigations show that the native oxide on the sample is replaced by self-assembled nanoarray by anodization. FESEM of samples annealed at 450 to 800 °C show tubular morphology whereas those annealed at 850 °C show collapse of nanotubes. Electrochemical impedance data of the substrate and 10 V anodized samples were fitted with a two-time constant equivalent circuit and that of anodized samples (20, 30 V) with a three-time constant equivalent circuit.

Electrochemical behaviour and bioactivity of self-organized TiO2 nanotube arrays on Ti-6Al-4V in Hanks’ solution for biomedical applications

Abstract: In the present work, the formation of self-organized titanium oxide nanotube layer by anodic oxidation on titanium alloy Ti-6Al-4V and its influence on growth of apatite on Ti-6Al-4V is reported. Anodization was carried out in sulfuric acid and hydrofluoric acid containing electrolyte and the anodized surface was characterized by micro-Raman, XRD and FESEM. The corrosion behavior of the anodized sample was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hanks’ solution). The influence of TiO2 nano tubes on the growth of apatite on the anodized sample was investigated by immersion in Hanks’ solution for 1 and 7 days. The investigations show that the native oxide on the sample is replaced by self assembled nanotube array by anodization. The anodic oxide consist both anatase and rutile. After vacuum annealing at 600 °C, intensity of rutile peak increased. FESEM of samples annealed at 450 °C show tubular morphology whereas those annealed at 600 °C show collapse of nano tubes. Corrosion resistance of the anodized sample was comparable with that of the untreated samples. Electrochemical impedance data of the substrate was fitted with two time constant equivalent circuit and that of anodized samples with three time constant equivalent circuit. FESEM images of immersed samples show that the growth of apatite is more with larger sized deposits on anodized surface as compared to that on the untreated substrate. XPS investigation of immersed sample shows presences of calcium, phosphorous and oxygen in hydroxide/phosphate form on the anodized sample.

Current Trends of Microfluidic Single-Cell Technologies.

Abstract: The investigation of human disease mechanisms is difficult due to the heterogeneity in gene expression and the physiological state of cells in a given population. In comparison to bulk cell measurements, single-cell measurement technologies can provide a better understanding of the interactions among molecules, organelles, cells, and the microenvironment, which can aid in the development of therapeutics and diagnostic tools. In recent years, single-cell technologies have become increasingly robust and accessible, although limitations exist. In this review, we describe the recent advances in single-cell technologies and their applications in single-cell manipulation, diagnosis, and therapeutics development.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

A critical review of multifunctional titanium surfaces: New frontiers for improving osseointegration and host response, avoiding bacteria contamination.

Abstract: Evolution of metal implants progressively shifted the focus from adequate mechanical strength to improved biocompatibility and absence of toxicity and, finally, to fast osseointegration. Recently, new frontiers and challenges of Ti implants have been addressed to improvement of bioactivity, fighting of bacterial infection and biofilm formation, as well as modulation of inflammation. This is closely related to the clinical demand of multifunctional implants able to simultaneously have a number of specific responses with respect to body fluids, cells (osteoblasts, fibroblasts, macrophages) and pathogenic agents (bacteria, viruses). This complex system of multiple biological stimuli and surface responses is a major arena of the current research on biomaterials and biosurfaces. This review covers the strategies explored to this purpose since 2010 in the case of Ti and Ti alloys, considering that the number of related papers doubled about in the last seven years and no review has comprehensively covered this engaging research area yet. The different approaches followed for producing multifunctional Ti-based surfaces involve the use of thick and thin inorganic coatings, chemical surface treatments, and functionalization strategies coupled with organic coatings. Statement of Significance According to the clinical demand of multifunctional implants able to simultaneously have a number of specific responses with respect to body fluids, cells and pathogenic agents, new frontiers of Ti implants have been addressed to improvement of bioactivity, fighting of bacterial infection and biofilm formation, as well as modulation of inflammation. Literature since 2010 is here reviewed. Several strategies for getting bioactive and antibacterial actions on Ti surfaces have been suggested, but they still need to be optimized with respect to several concerns. A further step will be to combine on the same surface a proven ability of modulation of inflammatory response. The achievement of multifunctional surfaces able to modulate inflammation and to promote osteogenesis is a grand challenge.

Advances in metals and alloys for joint replacement

Abstract: Metals, ceramics, polymers, and composites have been employed in joint arthroplasty with ever increasing success since the 1960s. New materials to repair or replace human skeletal joints (e.g. hip, knee, shoulder, ankle, fingers) are being introduced as materials scientists and engineers develop better understanding of the limitations of current joint replacement technologies. Advances in the processing and properties of all classes of materials are providing superior solutions for human health. However, as the average age of patients for joint replacement surgery decreases and the average lifespans of men and women increases worldwide, the demands upon the joint materials are growing. This article focuses solely on advances in metals, highlighting the current and emerging technologies in metals processing, metal surface treatment, and integration of metals into hybrid materials systems. The needed improvements in key properties such as wear, corrosion, and fatigue resistance are discussed in terms of the enhanced microstructures that can be achieved through advanced surface and bulk metal treatments. Finally, far reaching horizons in metals science that may further increase the effectiveness of total joint replacement solutions are outlined.

Electrophoretic deposition of chitosan-based composite coatings for biomedical applications: A review

Abstract: Chitosan is one of the most widely used natural biopolymers for a great variety of biomedical applications owing to its biocompatibility, biodegradability, and antibacterial activity, being generally regarded as a safe material. It can be employed as a dispersant, binder, and surface charge agent for particles in suspension. Electrophoretic deposition (EPD) of chitosan, especially in combination with other materials, is receiving increasing attention for biomedical applications. This article presents a comprehensive review of the field of EPD of chitosan-based composite coatings by highlighting their microstructural, mechanical, surface, and biological properties. Since suspension characteristics have significant influences on the deposition mechanisms, kinetics, and on the overall properties of the electrophoretically deposited coatings, suspension parameters such as concentration, viscosity, and zeta potential are discussed, including chitosan-based suspensions with hydroxyapatite, bioactive glass particles, carbonaceous materials and other inorganic and organic materials. The deposition mechanisms proposed for each composite system are highlighted. Moreover, the effects of key EPD process parameters on the microstructural homogeneity, mechanical properties as well as surface and biological characteristics of the coatings are emphasised, and specific approaches for future research are proposed based on the state-of-the-art and considering EPD produced chitosan-based coatings in applications such as tissue engineering and drug delivery systems.