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Das, Dipankar,Zhang, Shengmin,Noh, Insup Institute of Physics Publishing Ltd 2018 Biomedical Materials Vol.13 No.2
<P>A biocompatible hybrid film has been fabricated using alginate (Alg), alpha-tricalcium phosphate (alpha-TCP) microparticle and calcium chloride through ionic crosslinking as a biomaterial. The 'screeding method' (like a concrete finishing process) has been employed to develop the Alg-alpha-TCP film. For this method, the Alg/alpha-TCP blend has been prepared using an ultra-sonicator and then put on a glass slide. After that, the excess volume of blend has been cut off by skidding another slide along with the surface of the blend to achieve proper grade and flatness. The mechanical strength and flexibility of the film (Alg-alpha-TCP) has been controlled by changing its compositions. The crosslinking phenomenon has been confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), C-13 nuclear magnetic resonance (NMR), x-ray diffraction and thermogravimetric analyses. The ATR-FTIR and C-13 NMR analysis results suggest that carboxylate groups of the alginate are ionically cross-linked with Ca2+ ions, while the alpha-TCP particles reside in the network by physical interaction. The micro-fatigue test results imply high tensile strength (up to 257 MPa) and flexibility (up to 13% elongation) of the Alg-alpha-TCP hybrid films. The SEM analysis suggests the alpha-TCP particles are homogeneously distributed on the surface of Alg-alpha-TCP films, whereas cross-sectional images confirmed the presence of alpha-TCP in the cross-linked network. TGA results demonstrated that thermal stability of the hybrid film was enhanced due to ionic crosslinking and interfacial interaction between alginate and alpha-TCP. The incorporation of alpha-TCP particles diminished the swelling ratio of the hybrid film. The in vitro bone cell (MC3T3) culture and cytotoxicity tests showed that the hybrid film is biocompatible. The hybrid film releases bovine serum albumin and dimethyloxaloylglycine in a controlled way at pH7 and 7.4, and 37 degrees C. Overall, the biocompatible Alg-alpha-TCP hybrid film with excellent mechanical strength and flexibility could be applied as an interfacial film in tissue engineering.</P>
DIPANKAR DAS,Lakshmi Narayan Mishra 장전수학회 2019 Advanced Studies in Contemporary Mathematics Vol.29 No.3
In this paper, we introduce C- algebra valued modular b- metric spaces. Some common xed point theorems for JHR operator pairs with new contractive conditions via C-class functions in C- algebra valued modular b-metric spaces is given here with examples. Some applications on non linear integral equation and on operator equation is also introduced.
Multiple Object Detection and Localization using Range and Color Images for Service Robots
Dipankar Das,Yoshinori Kobayashi,Yoshinori Kuno 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In real-world applications, service robots need to locate and identify objects in ascene. A range sensor provides a robust estimate of depth information, which is useful to accurately locate objects in a scene. On the other hand, color information is an important property for object recognition task. The objective of this paper is to detect and localize multiple objects with in an image using both range and color features. The proposed method uses 3D shape features to generate promising hypotheses with in range images and verifies these hypotheses by using features obtaned from both range and color images.
Das, Dipankar,Cho, Hana,Kim, Nahye,Pham, Thi Thu Hien,Kim, In Gul,Chung, Eun-Jae,Noh, Insup Elsevier 2019 Carbohydrate Polymers Vol.207 No.-
<P><B>Abstract</B></P> <P>Here, we report synthesis of a terpolymeric covalently crosslinked hydrogel of hyaluronate (HA) as biomaterial with elasticity, mechanical properties and cell interactions <I>via</I> conventional free radical polymerization technique. To provide elasticity and mechanical properties, 2-hydroxyethyl acrylate (HEA) was grafted in HA, while to tune cellular interactions, gelatin methacryloyl (GM) was used as crosslinker. The composition and probable structure of the terpolymer (HA-g-pHEA-x-GM) were analysed by FTIR, <SUP>1</SUP>H HR-MAS-NMR, and TGA analyses. The SEM and texture analyses of hydrogel showed interconnected micro-porous network and high mechanical properties, respectively. <I>In vitro</I> biocompatibility was studied against human chondrocytes, whereas, <I>in vivo</I> biocompatibility and tissue regeneration were confirmed using mouse model. The hydrogel releases model protein-bovine serum albumin, and corticosteroid drug-dexamethasone in a sustain way at pH 7.4 and 37 °C. Overall, the tunable mechanical properties, micro-porous network, and cytocompatibility of the HA-g-pHEA-x-GM hydrogel highlights its potential applicability in cartilage tissue engineering and drug delivery.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hyaluronate-based terpolymeric gel was synthesized and physicochemically analysed. </LI> <LI> <I>In vitro</I> cell study showed chondrocytes survival and promotion of cell behaviours. </LI> <LI> <I>In vivo</I> biocompatibility was confirmed using mouse model. </LI> <LI> The hydrogel releases bovine serum albumin and dexamethasone in a sustain way. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Das, Dipankar,Pham, Thi Thu Hien,Noh, Insup Elsevier 2018 Colloids and surfaces. B, Biointerfaces Vol.170 No.-
<P><B>Abstract</B></P> <P>In the present study, a novel terpolymeric hydrogel was developed using sodium hyaluronate (HA), 2-hydroxyethyl acrylate (2-HEA), and poly(ethylene glycol) diacrylate (PEGDA) via free radical polymerization for biomedical applications. To achieve elasticity, swelling ability, porous architecture and sufficient gel strength, hyaluronate was chemically modified by grafting and crosslinking methods using 2-HEA and PEGDA, respectively. The structure and compositions of the fabricated terpolymer (HA-g-p(2-HEA)-x-PEGDA) were verified by FTIR, <SUP>1</SUP>H HR-MAS-NMR, and TGA analyses. The surface morphology and cross-section of the hydrogel was detected by SEM analysis. The gel nature of terpolymer in aqueous medium at 37 °C was confirmed from swelling study, and rheological experiment. Non-cytotoxicity and biocompatibility of the HA-g-p(2-HEA)-x-PEGDA hydrogel were ascertained by <I>in vitro</I> mouse osteoblastic cells (MC3T3) proliferation, and viability studies. Hematoxylin and eosin Y, and Masson’s trichrome stainings were performed to show tissue regeneration ability on the prepared hydrogel. <I>In vitro</I> release results of proangiogenic drug-dimethyloxalylglycine (DMOG), and antibiotics-tetracycline (TCN) showed sustained release behaviour from the prepared hydrogel under different pHs at 37 °C. The mathematical models fitted data imply that both DMOG and TCN release follow first order kinetics, while, the release mechanism is primarily controlled by diffusion as well as erosion process. Finally, the novel biocompatible HA-g-p(2-HEA)-x-PEGDA gel, which showed sustained drugs release, and regeneration ability of extracellular matrix and collagen, could be employed in biomedical applications, especially, for the delivery of DMOG/TCN, and in tissue engineering.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hyaluronate based terpolymeric hydrogel was developed by radical polymerization. </LI> <LI> The hydrogel is biocompatible and releases DMOG, and TCN drugs in a controlled way. </LI> <LI> Extracellular matrix, and collagen were developed after 3 weeks in the gel matrix. </LI> <LI> The synthesized hydrogel could be used for small defect in bone tissue engineering. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>