Muraleedharan CV

Publications

• 1.96

  Impact points

  Preparation and analysis of chemically gradient functional bioceramic coating formed by pulsed laser deposition.

  P Rajesh, C V Muraleedharan, S Sureshbabu, Manoj Komath, Harikrishna Varma

  Journal of materials science. Materials in medicine. 11/2011; 23(2):339-48.

  Bioactive ceramic coatings based on calcium phosphates yield better functionality in the human body for a variety of metallic implant devices including orthopaedic and dental prostheses. In the present study chemically and hence functionally gradient bioceramic coating was obtained by pulsed laser d... [more] Bioactive ceramic coatings based on calcium phosphates yield better functionality in the human body for a variety of metallic implant devices including orthopaedic and dental prostheses. In the present study chemically and hence functionally gradient bioceramic coating was obtained by pulsed laser deposition method. Calcium phosphate bioactive ceramic coatings based on hydroxyapatite (HA) and tricalcium phosphate (TCP) were deposited over titanium substrate to produce gradation in physico-chemical characteristics and in vitro dissolution behaviour. Sintered targets of HA and α-TCP were deposited in a multi target laser deposition system. The obtained deposits were characterized by X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis. Inductively coupled plasma spectroscopy was used to estimate the in vitro dissolution behaviour of coatings. The variation in mechanical property of the gradient layer was evaluated through scratch test and micro-indentation hardness. The bioactivity was examined in vitro with respect to the ability of HA layer to form on the surface as a result of contact with simulated body fluid. It could be inferred that chemically gradient functional bioceramic coating can be produced by laser deposition of multiple sintered targets with variable chemical composition.
• 2.19

  Impact points

  Evaluation of alginate dialdehyde cross-linked gelatin hydrogel as a biodegradable sealant for polyester vascular graft.

  Saraswathy Manju, Chirathodi Vayalappil Muraleedharan, Adathala Rajeev, Attipettah Jayakrishnan, Roy Joseph

  Journal of biomedical materials research. Part B, Applied biomaterials. 07/2011; 98(1):139-49.

  Vascular grafts are devices intended to replace compromised arteries in the body and grafts made of polyethylene terephthalate (PET) fabric have been used mainly for synthetic grafting procedures involving medium to large diameter vascular grafts. Though porosity of the graft permits tissue in-growt... [more] Vascular grafts are devices intended to replace compromised arteries in the body and grafts made of polyethylene terephthalate (PET) fabric have been used mainly for synthetic grafting procedures involving medium to large diameter vascular grafts. Though porosity of the graft permits tissue in-growth, it would lead to bleeding through the graft walls immediately after implantation. So it is essential to seal the pores either by preclotting with patient's own blood or by other sealing materials prior to implantation in order to prevent blood leakage through the graft wall. Biodegradable hydrogel materials are ideal candidates for this purpose. Apart from sealing the pores, they offer biocompatible and low-thrombogenic surfaces when coated on vascular graft. In the present study, a biodegradable hydrogel, derived from oxidized alginate and gelatin, has been deposited on PET grafts by dip coating and were characterized for its efficacy on sealing the pores of the graft. Water permeability in the static and pulsatile conditions, burst strength, in vitro cell culture cytotoxicity, hemocompatibility, and endothelial cell adhesion and proliferation of the coated grafts were investigated. Results showed that the alginate dialdehyde cross-linked gelatin hydrogel was nontoxic, hemocompatible, and was efficient in sealing the pores of the graft. Blood perfusion study showed that when hydrogel-coated grafts were exposed to blood for 30 min, they showed little affinity toward platelets or leukocytes. Hemolytic potential of PET was significantly reduced when it was coated with hydrogel. Improved adhesion and proliferation of endothelial cells were observed when PET grafts were coated with hydrogel. Results also showed that coating with hydrogel did not affect the burst strength of the PET graft.

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• 1.96

  Impact points

  Laser surface modification of titanium substrate for pulsed laser deposition of highly adherent hydroxyapatite.

  P Rajesh, C V Muraleedharan, Manoj Komath, Harikrishna Varma

  Journal of materials science. Materials in medicine. 05/2011; 22(7):1671-9.

  Biomedical implant devices made out of titanium and its alloys are benefited by a modified surface or a bioactive coating to enhance bone bonding ability and to function effectively in vivo for the intended period of time. In this respect hydroxyapatite coating developed through pulsed laser deposit... [more] Biomedical implant devices made out of titanium and its alloys are benefited by a modified surface or a bioactive coating to enhance bone bonding ability and to function effectively in vivo for the intended period of time. In this respect hydroxyapatite coating developed through pulsed laser deposition is a promising approach. Since the success of the bioactive ceramic coated implant depends mainly on the substrate-coating strength; an attempt has been made to produce micro patterned surface structure on titanium substrate for adherent hydroxyapatite coating. A pulsed Nd-YAG laser beam (355 nm) with 10 Hz repetition rate was used for surface treatment of titanium as well as hydroxyapatite deposition. The unfocussed laser beam was used to modify the substrate surface with 500-18,000 laser pulses while keeping the polished substrate in water. Hydroxyapatite deposition was done in a vacuum deposition chamber at 400 °C with the focused laser beam under 1 × 10⁻³ mbar oxygen pressure. Deposits were analyzed to understand the physico-chemical, morphological and mechanical characteristics. The obtained substrate and coating surface morphology indicates that laser treatment method can provide controlled micro-topography. Scratch test analysis and microindentation hardness values of coating on laser treated substrate indicate higher mechanical adhesion with respect to coatings on untreated substrates.
• 1.79

  Impact points

  A comparative study of titanium nitride (TiN), titanium oxy nitride (TiON) and titanium aluminum nitride (TiAlN), as surface coatings for bio implants

  B Subramanian, CV Muraleedharan, R Ananthakumar, M Jayachandran

  Surface and Coatings Technology. 05/2011;
• 1.96

  Impact points

  Pulsed laser deposition of hydroxyapatite on titanium substrate with titania interlayer.

  P Rajesh, C V Muraleedharan, Manoj Komath, Harikrishna Varma

  Journal of materials science. Materials in medicine. 01/2011; 22(3):497-505.

  Pulsed laser deposition (PLD) has been used to deposit hydroxyapatite (HA) ceramic over titanium substrate with an interlayer of titania. PLD has been identified as a potential candidate for bioceramic coatings over metallic substrates to be used as orthopedic and dental implants because of better p... [more] Pulsed laser deposition (PLD) has been used to deposit hydroxyapatite (HA) ceramic over titanium substrate with an interlayer of titania. PLD has been identified as a potential candidate for bioceramic coatings over metallic substrates to be used as orthopedic and dental implants because of better process control and preservation of phase identity of the coating component. However, direct deposition of hydroxyapatite on titanium at elevated temperature results in the formation of natural oxide layer along with some perovskites like calcium titanate at the interface. This leads to easy debonding of ceramic layer from the metal and thereby affecting the adhesion strength. In the present study, adherent and stable HA coating over Ti6Al4V was achieved with the help of an interlayer of titania. The interlayer was made to a submicron level and HA was deposited consecutively to a thickness of around one micron by exposing to laser ablation at a substrate temperature of 400°C. The deposited phase was identified to be phase pure HA by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and inductively coupled plasma spectrometry. The mechanical behavior of coating evaluated by scratch test indicates that the adhesion strength of HA coating was improved with the presence of titania interlayer.
• 1.96

  Impact points

  Reference biomaterials for biological evaluation.

  Leena Joseph, Arumugham Velayudhan, Muraleedharan V Charuvila, Muraleedharan C Vayalappil

  Journal of materials science. Materials in medicine. 12/2009; 20 Suppl 1:S9-17.

  The variability associated with most of the biological evaluation studies is relatively large and hence experimental controls are frequently employed to ensure that the results are reliable. These experimental controls, either positive or negative controls, could be considered as reference materials... [more] The variability associated with most of the biological evaluation studies is relatively large and hence experimental controls are frequently employed to ensure that the results are reliable. These experimental controls, either positive or negative controls, could be considered as reference materials in the context of biological evaluation. Currently, reference biomaterial needs across the world are not addressed satisfactorily. Affordability and lack of availability of certified reference materials necessitates the development and the use of laboratory developed RMs. A well defined characterization strategy is essential for the successful development of in house reference materials. This article provides an overview of the current international status in the area of reference biomaterials and enumerates the steps involved in the development of an in house reference material. The production and characterization of commercially pure titanium pins for use as negative controls during muscle implantation studies is presented as a case study.

• Titanium Nitride and Diamond Like carbon for cardiovascular applications

  Muraleedharan CV, Bhuvaneshwar GS

  01/2009;

• Validation in medical devices

  Muraleedharan CV

  01/2009: pages 36-57;

  ISBN: 978-81-908710-0-6
• 1.96

  Impact points

  Characterization of surface modified polyester fabric.

  Roy Joseph, R Shelma, A Rajeev, C Muraleedharan

  Journal of materials science. Materials in medicine. 07/2008;

  Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by di... [more] Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.
• 2.82

  Impact points

  Bio-mimetic composite matrix that promotes endothelial cell growth for modification of biomaterial surface.

  C Krishna Prasad, C V Muraleedharan, Lissy K Krishnan

  Journal of biomedical materials research. Part A. 04/2007; 80(3):644-54.

  The incidence of thrombogenesis and occlusion of cardiovascular implants is likely to be reduced by endothelial cell (EC) growth promotion on biomaterials used for device fabrication. However, proper signaling between the matrix proteins deposited on the device surface and the cells grown on it is a... [more] The incidence of thrombogenesis and occlusion of cardiovascular implants is likely to be reduced by endothelial cell (EC) growth promotion on biomaterials used for device fabrication. However, proper signaling between the matrix proteins deposited on the device surface and the cells grown on it is a prime requirement for growth and function. It was demonstrated earlier that a composition of matrix proteins that include fibrin, fibronectin, gelatin, and growth factors maintain a steady proliferation potential and prolong the survival of endothelial cells in vitro. In this study, assessment of the same matrix to prevent EC from dedifferentiation during in vitro culture and to promote endothelialization of biomaterials used for fabrication of cardiovascular implants is carried out. Up/down regulation of m-RNA expression for a prothrombotic molecule-plasminogen activator inhibitor (PAI), and two antithrombotic molecules- nitric oxide synthetase (eNOS) and tissue plasminogen activator (t-PA) are chosen as the indicators of cell dedifferentiation during cell culture and passaging. Immunostaining for vinculin and actin demonstrated that composite coating on biomaterials improves focal adhesion and cytoskeletal organization that increases the quality of EC grown on it. EC proliferation, measured by (3)H-thymidine uptake, on all bare materials was poor and high incidence of cell apoptosis was noticed within 72 h in culture, whereas once coated with composite all materials showed good proliferation and survival. The results suggest that the designed composition of biomimetic adhesive proteins and growth factors is suitable for EC growth, survival, and functional integrity, thus making it suitable for cardiovascular tissue engineering that requires in vitro EC culture.

• Validation as a quality assurance tool in GLP environment

  Muraleedharan CV

  01/2006;

• The saga of Chitra heart valve prosthesis

  Muraleedharan CV, Bhuvaneswar GS

  01/2005;
• 3.17

  Impact points

  Long term tissue response to titanium coated with diamond like carbon.

  M Mohanty, T V Anilkumar, P V Mohanan, C V Muraleedharan, G S Bhuvaneshwar, F Derangere, Y Sampeur, R Suryanarayanan

  Biomolecular engineering. 09/2002; 19(2-6):125-8.

  Diamond like carbon (DLC) coatings were deposited on to Ti substrates by plasma enhanced chemical vapor deposition technique. Ti and DLC/Ti samples were implanted in skeletal muscle of rabbits. The samples were explanted after 1, 3, 6 and 12 months and the tissue-cell interaction was studied. Our da... [more] Diamond like carbon (DLC) coatings were deposited on to Ti substrates by plasma enhanced chemical vapor deposition technique. Ti and DLC/Ti samples were implanted in skeletal muscle of rabbits. The samples were explanted after 1, 3, 6 and 12 months and the tissue-cell interaction was studied. Our data indicate both DLC/Ti and bare Ti to be compatible with skeletal muscle.
• 3.17

  Impact points

  Quantitation of platelet adhesion to Ti and DLC-coated Ti in vitro using (125)I-labeled platelets.

  L K Krishnan, N Varghese, C V Muraleedharan, G S Bhuvaneshwar, F Derangère, Y Sampeur, R Suryanarayanan

  Biomolecular engineering. 09/2002; 19(2-6):251-3.

  Measurement of platelet adhesion in vitro is a good indicator of its reactivity to implant devices in vivo. Platelets were labeled with I-125 without affecting its normal morphology and function and the labeled platelets were suspended in platelet poor plasma and exposed to Ti and diamond like carbo... [more] Measurement of platelet adhesion in vitro is a good indicator of its reactivity to implant devices in vivo. Platelets were labeled with I-125 without affecting its normal morphology and function and the labeled platelets were suspended in platelet poor plasma and exposed to Ti and diamond like carbon-coated (DLC) Ti discs, under dynamic conditions, using a parallel plate flow chamber. The test materials were washed, dried, exposed to a phosphor screen and scanned to get the images. The number of platelets that adhered to Ti was found to be higher than those that adhered to DLC coated Ti sample, irrespective of the shear stress which was varied between 2 and 16 dynes/cm(2).
• 0.62

  Impact points

  In vitro cytocompatibility studies of Diamond Like Carbon coatings on titanium.

  T V Kumari, P R Anil Kumar, C V Muraleedharan, G S Bhuvaneshwar, Y Sampeur, F Derangere, R Suryanarayanan

  Bio-medical materials and engineering. 02/2002; 12(4):329-38.

  Diamond like carbon (DLC) films were deposited on to titanium (Ti) substrates by Plasma Enhanced Chemical Vapour Deposition (PECVD) process. The quality of the films were checked by Raman spectra and nano-hardness tests. The cytocompatibility of titanium and DLC coated titanium were studied using co... [more] Diamond like carbon (DLC) films were deposited on to titanium (Ti) substrates by Plasma Enhanced Chemical Vapour Deposition (PECVD) process. The quality of the films were checked by Raman spectra and nano-hardness tests. The cytocompatibility of titanium and DLC coated titanium were studied using continuous cell lines of mouse fibroblast cells ( L-929), Human Osteoblast cells (HOS) and primary human umbilical cord vein endothelial cells (HUVEC). The cellular responses to the materials were assessed both quantitatively and qualitatively. The adhesion and spreading of cells on materials were compared using Ti as a control. Present study indicates an improved cytocompatibility of DLC coated Ti in comparison to bare Ti.
• 1.03

  Impact points

  Development of the Chitra tilting disc heart valve prosthesis.

  G S Bhuvaneshwar, C V Muraleedharan, G A Vijayan, R S Kumar, M S Valiathan

  The Journal of heart valve disease. 08/1996; 5(4):448-58.

  BACKGROUND AND AIMS OF THE STUDY: The high prevalence of rheumatic valvular disease in the young population and the high cost of imports necessitated the development of an Indian valve. The development of a tilting disc prosthesis was successfully concluded in February 1995, when the third model com... [more] BACKGROUND AND AIMS OF THE STUDY: The high prevalence of rheumatic valvular disease in the young population and the high cost of imports necessitated the development of an Indian valve. The development of a tilting disc prosthesis was successfully concluded in February 1995, when the third model completed its clinical trial. The tilting disc valve has an integrally machined cobalt alloy cage, an ultra high molecular weight polyethylene disc and a polyester suture ring. The choice of design was based on its superior hydrodynamics and the age distribution of patients, the majority of whom were below 30 years. The polymer-metal combination was selected for its extremely low wear rate and proven durability in the human body. MATERIALS AND METHODS: The hydrodynamic performance was tested under steady and pulsatile flow conditions. The accelerated durability of nine test valves was evaluated at 800-840 cycles/min for over 350 million cycles each. Size 23 mm valves mere implanted in the mitral position of five sheep. In a clinical trial, 306 patients with isolated mitral or aortic valve replacements were followed up for a total of 371 patient years (mean 1.37 years and range 0-4 years). RESULTS: The hydrodynamic performance was comparable to that of proven clinical models. The accelerated testing indicated lifetimes in excess of 50 years and the animal trials showed the valve to be safe. In the clinical trial, there was no incidence of structural failure or paravalvular leak. The linearized rate of late thromboembolism was 6.2%/patient-year (pty), anticoagulant related hemorrhage 0.54%/pty and infective endocarditis 0.54%/pty. At two years, the total actuarial survival was 89.5%. The higher incidence of thromboembolism and the very low incidence of anticoagulant related hemorrhage illustrate the difficulty in the management of anticoagulant therapy in a developing country, while the low incidence of endocarditis reflects their greater resistance to infection. CONCLUSION: These data clearly showed the valve to be safe and comparable to other similar valves in clinical use.

• Failure mode and effect analysis of Chitra heart valve prosthesis

  C.V. Muraleedharan, G.S. Bhuvaneshwar

  Engineering in Medicine and Biology Society, 1995 and 14th Conference of the Biomedical Engineering Society of India. An International Meeting, Proceedings of the First Regional Conference., IEEE; 03/1995

  Artificial heart valves are devices used for replacing diseased natural valves of the human heart. The failure of such a device to perform to its requirements can lead to serious complications, even threatening the life of the recipient. There are many and varied modes of valve failure that can lead... [more] Artificial heart valves are devices used for replacing diseased natural valves of the human heart. The failure of such a device to perform to its requirements can lead to serious complications, even threatening the life of the recipient. There are many and varied modes of valve failure that can lead to departure from specifications. These failure mechanisms can be broadly classified into (1) intrinsic factors, like prosthesis design, materials and fabrication processes, and (2) extrinsic factors due to remodelling of the heart and lungs subsequent to valvular disease and valve replacement. This failure mode and effect analysis (FMEA) is an attempt to identify the various possible failure modes of the Chitra heart valve prosthesis

• PC based instrumentation as an economic method for quality assurance-an experience based on development of hydrocephalus shunt test system

  D.S. Nagesh, S.K. Srinivasan Nair, C.V. Muraleedharan, G.S. Bhuvaneshwar

  Engineering in Medicine and Biology Society, 1995 and 14th Conference of the Biomedical Engineering Society of India. An International Meeting, Proceedings of the First Regional Conference., IEEE; 03/1995

  A PC based system is an attractive alternative to conventional methods of industrial quality assurance for its high reliability at lower cost. A custom assembled system with user friendly software is ideal for industries, especially when the quantity requirement is small. This concept is illustrated... [more] A PC based system is an attractive alternative to conventional methods of industrial quality assurance for its high reliability at lower cost. A custom assembled system with user friendly software is ideal for industries, especially when the quantity requirement is small. This concept is illustrated with an example of the development of a PC based test system for the quality assurance of hydrocephalus shunt-a neurosurgical implant. During the technology transfer of the device, a 16 channel PC controlled test system has been developed for classifying the device according to their pressure-flow characteristics. Here, the speed of the multichannel peristaltic pump is controlled for various flow rates ranging from 5 ml/hour to 50 ml/hour and the corresponding pressure drop sensed by the transducer is amplified, digitized and monitored. Depending on the measured values, the software classifies all the accepted devices in appropriate ranges and rejects the rest. The test results are printed out in proper format. All the subsystems and components used are in modular form and are standard products of leading manufacturers, enabling the user industry to operate and maintain the system without the help of the developer
• 1.83

  Impact points

  Prevention of calcification of tissue valves.

  J Chanda, S B Rao, M Mohanty, A V Lal, C V Muraleedharan, G S Bhuvaneshwar, M S Valiathan

  Artificial organs. 11/1994; 18(10):752-7.

  In this study an attempt was made to find an optimum method of chemical treatment to prevent the calcification of bioprosthetic heart valves. Bovine pericardium was washed in a 5% sodium chloride solution followed by trypsin (Tr) treatment and was kept in 0.1% glutaraldehyde (GA) with a gradual incr... [more] In this study an attempt was made to find an optimum method of chemical treatment to prevent the calcification of bioprosthetic heart valves. Bovine pericardium was washed in a 5% sodium chloride solution followed by trypsin (Tr) treatment and was kept in 0.1% glutaraldehyde (GA) with a gradual increase in concentration up to 0.25% GA and finally posttreated with a 4% chitosan (Ch) solution. Fresh, 0.2% GA, 0.625% GA, and sodium chloride-Tr-GA treated pericardial samples were taken for comparative study. Tensile testing showed comparable strength and elongation at the breaking point for all groups. The thermal shrinkage studies indicated merit of the proposed treatment (5% sodium chloride-trypsin-glutaraldehyde treated pericardia with chitosan and without chitosan posttreatment). Collagenase assay showed that all differently treated (GA) materials were equally resistant to collagenase. All samples were implanted subcutaneously in rats for 2, 4, 8, or 12 weeks for calcification study. Morphological and mineral analyses showed complete prevention of calcification in sodium chloride-trypsin-GA-chitosan treated pericardium (Ca was 1.1 +/- 0.27 mg/g, von Kossa 0) at the 12th week of implantation.
• 7.88

  Impact points

  Use of glutaraldehyde-gentamicin-treated bovine pericardium as a wound dressing.

  J Chanda, S B Rao, M Mohanty, C V Muraleedharan, V L Arthur, G S Bhuvaneshwar, M S Valiathan

  Biomaterials. 02/1994; 15(1):68-70.

  Glutaraldehyde (GA)-pretreated gentamicin post-fixed bovine pericardium has been evaluated as a wound dressing in this study. Two excisions approximately 7 x 4 cm, each of full thickness skin, from the upper and lower parts down to, but not including, the panniculus carnosus were made from the back ... [more] Glutaraldehyde (GA)-pretreated gentamicin post-fixed bovine pericardium has been evaluated as a wound dressing in this study. Two excisions approximately 7 x 4 cm, each of full thickness skin, from the upper and lower parts down to, but not including, the panniculus carnosus were made from the back of the guinea pig. The skin excised from the upper part was placed on the wound bed of the lower part as an autograft, whereas the upper wound was closed using 5% sodium chloride-trypsin-0.1% GA-0.048% gentamicin-treated bovine pericardium and sutured for comparative study. The wounds were inspected every 3-6 d for infection and exudation. Histopathological studies were performed at weekly intervals in the post-operative period. At the fifth week, a very thin linear scar on the epidermal aspect without remarkable contracture was observed and histopathology showed the completion of epithelization across the wounds in all cases. This study demonstrates that GA-pretreated, gentamicin-post-fixed bovine pericardium may be used as an alternative biological dressing in the case of large wounds.