Praveen Kumar Sehgal

Central Leather Research Institute, Chennai, Tamil Nādu, India

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Publications (63)119.05 Total impact

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    ABSTRACT: This work discusses the preparation and characterization of novel collagen scaffolds by using unnatural D-amino acids (Coll-D-AAs)-assisted 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxyl succinimide(NHS)-initiated crosslinking. The mechanical strength, hydrothermal and structural stability, resistance to biodegradation and the biocompatibility of Coll-D-AAs matrices were investigated. The results from Thermo mechanical analysis, Differential scanning calorimetric analysis and Thermo gravimetric analysis of the Coll-D-AAs matrices indicate a significant increase in the tensile strength (TS, 180 ± 3), % elongation (% E, 80 ± 9), elastic modulus (E, 170 ± 4) denaturation temperature (T d, 108 ± 4) and a significant decrease in decomposition rate (T g, 64 ± 6). Scanning electron microscopic and Atomic force microscopic analyses revealed a well-ordered with properly oriented and well-aligned structure of the Coll-D-AAs matrices. FT-IR results suggest that the incorporation of D-AAs favours the molecular stability of collagen matrix. The D-AAs stabilizing the collagen matrices against degradation by collagenase would have been brought about by protecting the active sites in collagen. The Coll-D-AAs matrices have good biocompatibility when compared with native collagen matrix. Molecular docking studies also indicate better understanding of bonding pattern of collagen with D-AAs. These Coll-D-AAs matrices have been produced in high mechanical strength, thermally and biologically stable, and highly biocompatible forms that can be further manipulated into the functional matrix suitable in designing scaffolds for tissue engineering and regenerative medical applications.
    Journal of Biomaterials Science Polymer Edition 02/2013; 24(3):344-64. · 1.70 Impact Factor
  • Journal of Cleaner Production 01/2013; · 3.59 Impact Factor
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    ABSTRACT: A biodurable porous scaffold of collagen with good biocompatibility and enhanced wound healing potential is prepared through casting technique using tannic acid (TA) as crosslinker. The morphological analysis of the tannic acid cross-linked collagen scaffold (TCCs) distinctively shows scaly interlinks with large pores. The enzymatic stability of the scaffold is characterized in vitro to detail the role of TA in stabilization of collagen matrix against collagenolytic degradation. TCCs shows more stability (>54%) against collagenase than that of the collagen scaffolds (Cs). The attenuated total reflectance Fourier transform infrared analysis of the TCCs confirms the noncovalent interaction between collagen and TA. The biocompatibility of the scaffold (TCCs) in vitro has been established using 3T3 fibroblasts. Therapeutic and wound healing potential of the TCCs has been studied in vivo using excision wound model in rats. The results clearly indicates that the TCCs has greater and significant effect in wound closure and increased the wound healing rate compared with native Cs. This biocompatible and biodurable scaffold may find broad applications in the tissue engineering and drug delivery applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
    Journal of Biomedical Materials Research Part B Applied Biomaterials 12/2012; · 2.31 Impact Factor
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    Dataset: Reprint 3
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    Dataset: Reprint 4
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    ABSTRACT: This work discusses the preparation and characterization of collagen scaffold with presence of D-Lysine (Coll-D-Lys)-assisted 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-initiated cross linking. The mechanical strength, thermal and structural stability, resistance to biodegradation and cell viability of this scaffold was investigated. The results of the Coll-D-Lys-EDC/NHS scaffold also indicate an increase in the tensile strength (T(S) ), percentage of elongation (% E), denaturation temperature (T(d) ), and decrease the decomposition rate. Scanning electron microscopic (SEM) and atomic force microscopic (AFM) analyses revealed a well ordered with properly oriented and well-aligned structure of scaffold. The D-Lys stabilizes the scaffold against degradation by collagenase than L-Lys. The cell assay showed more than 98 ± 2% fibroblast viability (NIH 3T3) after 72 h of culture Coll-D-Lys-scaffold when compared with native Coll and Coll-L-Lys-scaffold. The proteolytic machinery is not well equipped to deal with Coll-D-Lys-scaffold than Coll-L-Lys-scaffold. Incorporating D-Lys in scaffold design has the potential to improve existing collagen stability and create new topologies inaccessible to homochiral molecules. This method may assist in the functionalization of the scaffold for regenerative applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
    Journal of Biomedical Materials Research Part A 10/2012; · 2.83 Impact Factor
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    ABSTRACT: The present work reports the preparation of Poly L-Lactide (PLLA) and Curcumin loaded Poly L-Lactide (CPLLA) nanofibers by electrospinning. A series of PLLA solution (12 wt %) and C-PLLA (12 wt % PLLA) solution containing Curcumin (0.5 wt % and 1 wt %)) were electrospun into nanofibers. SEM images showed the average diameter of PLLA and C-PLLA in the range of 50–200 nm. The TEM images showed the dispersion of Curcumin on C-PLLA nanofibers. The XRD pattern indicated decreases of crystallinity with the increase in the amount of Curcumin. The characteristic peak of Curcumin was confirmed by FTIR. The TGA results showed the degradation of PLLA and C-PLLA close to 300 °C. The percentage porosity and the contact angle of PLLA were found to be 90.2 % and 115±3 ° with deionised water, respectively. The water uptake percentage was found to be 17.6 %. The percentage cumulative release of Curcumin at the end of 8th day for 0.5 and 1.0 wt % formulations was 81.4±1.3 and 86.7±1.7 % respectively. The in-vitro biological cytotoxicity studies were performed using C6 glioma cells and NIH 3T3 fibroblast by MTT assay and SEM analysis.
    Fibers and Polymers 09/2012; 2012, 13,:823-830. · 1.11 Impact Factor
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    Hadassah Janumala, Praveen Kumar Sehgal, Asit Baran Mandal
    Keratitis, 04/2012; , ISBN: 978-953-51-0568-8
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    ABSTRACT: Electrospinning is a desired method to produce ultrathin fibers for tissue engineering. In order to mimic the nanofibrous structure of the extracellular matrix (ECM) poly(propylene carbonate) ultrathin fibers were electrospun using N,N-dimethyl acetamide as solvent. Cationic surfactant, cetyl trimethyl ammonium bromide, was found to aid in the formation of beadless fibers of poly(propylene carbonate). Electrospinning parameters viz. concentration of polymer and that of the surfactant used as an additive, flow rate, electrostatic field, and effect of inner diameter of the needle were investigated and optimized. Scanning electron microscopy showed porous scaffold and fibers of diameter ranging from nano- to submicron range. FTIR spectroscopy and thermal analysis of the obtained fibers ensured the complete evaporation of solvent and optimal thermal stability of fibers for tissue engineering applications. The prepared fibers possess Young's modulus of 10.19 and 26.39 GPa with the tensile strengths of 22.11 and 21.29 MPa under dry and wet conditions, respectively. The fiber mat was measured to have a porosity of 48% and exhibited competent water retention capacity of 64%. Furthermore the scaffold was found to support the adhesion of mouse NIH 3T3 fibroblasts proving its mettle as a potential scaffold for tissue engineering applications.
    Advanced Engineering Materials 04/2012; 14(4). · 1.61 Impact Factor
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    ABSTRACT: In the present study, green and sustainable method or eco-friendly approaches to tanning process based on unnatural D-amino acids (D-AA)-aldehyde (Ald) as a substitute for chrome-free tanning has been attempted. The distribution of optically active D-AA in tanned leather, the hydrothermal stability, the mechanical properties and resistance to collagenolytic activity of tanned leather, the evaluation of eco-friendly characteristics were investigated. Scanning electron microscopic (SEM) and Atomic force microscopic (AFM) analyses indicate the surface morphology and roughness, respectively, of the tanned leather collagen matrix. Shrinkage and Differential scanning calorimetric (DSC) analyses shows that the shrinkage temperature (T(s)) and denaturation temperature (T(d)) of tanned leather are related to the content of D-AA+Ald present in the leather matrix. It has been found that the T(s) of D-AA tanned leather is more than that of Ald tanned leather and also more or less equal to chrome tanned leather. Environmental impact assessment (EIA) shows that the developed process results in significant reduction in total solids content (TSC) and improves better biodegradability of organic compound present in the effluent compared to chrome tanning.
    Journal of hazardous materials 02/2012; 215-216:173-82. · 4.33 Impact Factor
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    Materials Science and Engineering C 02/2012; · 2.40 Impact Factor
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    ABSTRACT: Poly(caprolactone) (PCL) electrospun nanofibers were modified by aminolysis and collagen was immobilized on the aminolysed PCL nanofibers. Considering low immunogenic response collagen elicits, immobilization of the same is anticipated to enhance the tissue engineering application of the PCL nanofibers. Amino groups were introduced into PCL nanofibers through aminolysis process. Aminolysis of PCL nanofibers was confirmed by electron dispersive X-ray analysis (EDX). Collagen was immobilized on aminolysed PCL nanofibers using glutaraldehyde as crosslinker. The collagen crosslinking on to PCL nanofibers was established by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The fiber morphologies of PCL nanofibers at different stages were characterized by scanning electron microscopy (SEM). The change in hydrophobicity of PCL nanofibers due to aminolysis and collagen immobilization was determined by water contact angle measurements. Aminolysis followed by collagen immobilization had reduced the intrinsic hydrophobicity of PCL nanofibers. NIH 3T3 fibroblasts were cultured for 2 days on PCL nanofibers, aminolysed PCL nanofibers, and aminolysed PCL nanofibers crosslinked with collagen. Cell attachment and growth were observed by MTT assay in each case. Collagen immobilization improved the biocompatibility of the PCL nanofibers. Thus the modified PCL nanofibers can be used as suitable broad spectrum scaffold for skin, cartilage, bone, cardiac constructs for efficient tissue engineering applications.
    Advanced Engineering Materials 10/2011; 14(4):B149-B154. · 1.61 Impact Factor
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    ABSTRACT: Gingival recession (GR) can result in root sensitivity, esthetic concern to the patient, and predilection to root caries. The purpose of this randomized clinical study was to evaluate (1) the effect of guided tissue regeneration (GTR) procedure using a bioabsorbable collagen membrane, in comparison to autogenous subepithelial connective tissue graft (SCTG) for root coverage in localized gingival recession defects; and (2) the change in width of keratinized gingiva following these two procedures. A total of 10 cases, showing at least two localized Miller's Class I or Class II gingival recession, participated in this study. In a split mouth design, the pairs of defects were randomly assigned for treatment with either SCTG (SCTG Group) or GTR-based collagen membrane (GTRC Group). Both the grafts were covered with coronally advanced flap. Recession depth (RD), recession width (RW), width of keratinized gingiva (KG), probing depth (PD), relative attachment level (RAL), plaque index (PI), and gingival index (GI) were recorded at baseline, 3 and 6 months postoperatively. Six months following root coverage procedures, the mean root coverage was found to be 84.84% ± 16.81% and 84.0% ± 15.19% in SCTG Group and GTRC Group, respectively. The mean keratinized gingival width increase was 1.50 ± 0.70 mm and 2.30 ± 0.67 mm in the SCTG and GTRC group, respectively, which was not statistically significant. It may be concluded that resorbable collagen membrane can be a reliable alternative to autogenous connective tissue graft in the treatment of gingival recession.
    Journal of Indian Society of Periodontology 10/2011; 15(4):353-8.
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    ABSTRACT: We report the detailed studies on the inhibitory effect of tannic acid (TA) on Clostridium histolyticum collagenase (ChC) activity against degradation of extracellular matrix component of collagen. The TA treated collagen exhibited 64% resistance against collagenolytic hydrolysis by ChC, whereas direct interaction of TA with ChC exhibited 99% inhibition against degradation of collagen and the inhibition was found to be concentration dependant. The kinetic inhibition of ChC has been deduced from the extent of hydrolysis of N-[3-(2-furyl) acryloyl]-Leu-Gly-Pro-Ala (FALGPA). This data provides a selective competitive mode of inhibition on ChC activity seems to be influenced strongly by the nature and structure of TA. TA showed inhibitor activity against the ChC by molecular docking method. This result demonstrated that TA containing digalloyl radical possess the ability to inhibit the ChC. The inhibition of ChC in gaining new insight into the mechanism of stabilization of collagen by TA is discussed.
    Journal of Enzyme Inhibition and Medicinal Chemistry 08/2011; 27(3):451-7. · 1.50 Impact Factor
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    ABSTRACT: The irreversible destruction of extracellular matrix (ECM) such as cartilage, tendon, and bone that comprise synovial joints is the hallmark of both rheumatoid arthritis and osteoarthritis by over-expression of matrix metalloproteinase (MMP)-collagenases. We report herein the detailed study on the inhibitory effects of Withania somnifera extract (WSE) and Cardiospermum halicacabum extract (CHE) on Clostridium histolyticum collagenase (ChC) activity against the degradation of the ECM component of bovine Achilles tendon type I collagen by hydroxyproline assay method. Interaction of WSE and CHE with ChC exhibited 71% and 88% inhibition, respectively, to the collagenolytic activity of ChC against collagen degradation, and the inhibition was found to be concentration-dependent. The inhibition kinetics of ChC by both the extracts has been deduced from the extent of hydrolysis of N-[3-(2-furyl) acryloyl]-Leu-Gly-Pro-Ala. Both WSE and CHE are provided competitive and mixed type inhibition on ChC activity, respectively. Circular dichroism studies of ChC on treatment with WSE and CHE revealed changes in the secondary structure of collagenase. These results suggest that the WSE and CHE facilitated collagen stabilization through collagenase inhibition.
    Applied biochemistry and biotechnology 07/2011; 165(3-4):1075-91. · 1.94 Impact Factor
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    ABSTRACT: In this study, we report on physical and in vitro biological characterization of succinylated collagen (SC). SC was prepared by succinylation of type I bovine tendon collagen. SC swells and dissolves in physiological pH buffers (pH 7.4) Biocompatibility of SC to collagen for fibroblasts was comparable but L6 myoblasts showed pronounced proliferation and differentiation with SC. Using the MALDI-TOF/MS technique, SC was found with increased molecular mass by 16,359 Da per molecule which corresponds to about 54 succinyl groups covalently linked to the collagen strand. Raman spectroscopy revealed the retention of triple helical structure conformation in the presence of linked succinyl groups. New peaks near 1737, 1675 and 1420 cm�1 and decreased intensities near 2440 and 488 cm�1 provides the most convenient marker bands for succinylation of collagen. The intense band regions near 2856–2934, 2724, and 1445 cm�1 also confirms the existence of succinyl groups
    Journal of Molecular Structure THEOCHEM 05/2011; 994:117-124. · 1.37 Impact Factor
  • Soft Materials 01/2011; · 1.43 Impact Factor
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    ABSTRACT: Fabrication of keratin–collagen (KC) 3D scaffold with improved thermal denaturation rate is reported. In vitro application of (KC) scaffold stimulates basic extra cellular matrix constituents. KC Scaffold considerably reduced undesirable properties of both collagen and keratin while collagen incorporation reduces the fragility with increases of strength and flexibility in the scaffold. In addition to this, the scaffold showed homogenous well-interconnected pores in the range of 10–100 µm when observed in scanning electron microscope. Usage of keratin in KC scaffold offers increased biodegradation rate and higher denaturation rate in addition to its rapid cell growth with normal morphology ultimately reaching cell population of 3.9–9.7 million per cm3 after 48 hr in KC scaffold. Circular dichroism (CD) and Fourier transform spectroscopy (FT-IR) of KC showed presence of helical structure of collagen and ß-turns of keratin confirming retention of native structures of both the proteins KC scaffold showed good swelling behavior and water uptake. Our study strongly supports the superidity of KC scaffold over the collagen or keratin when they are independently used for tissue engineering applications.
    Polymers for Advanced Technologies 01/2011; · 1.64 Impact Factor
  • Reactive and Functional Polymers 01/2011; 71:62–69. · 2.51 Impact Factor
  • XXXI IULTCS Congress proceedings 2011; 01/2011

Publication Stats

435 Citations
119.05 Total Impact Points

Institutions

  • 1997–2013
    • Central Leather Research Institute
      • Bio-Products Laboratory (CLRI)
      Chennai, Tamil Nādu, India
  • 2010
    • Monash University (Australia)
      Melbourne, Victoria, Australia
  • 2007
    • Sri Ramachandra University
      • Department of Cardio-Thoracic Surgery
      Porur, State of Tamil Nadu, India