Browsing by Author "Sreeram, KJ"

Now showing 1 - 4 of 4
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    Flower shaped assembly of cobalt ferrite nanoparticles: application as T-2 contrast agent in MRI
    (RSC ADVANCES, 2013) Nidhin, M; Nazeer, SS; Jayasree, RS; Kiran, MS; Nair, BU; Sreeram, KJ
    Material research has moved from generalization to specificity. Progress of nanoscience from synthesis to application oriented tailored synthesis has generated keen interest in the subject. The electrical and magnetic properties of spinel ferrites is one area of nanoscience that is slowing progress towards application oriented research. In this, CoFe2O4, owing to high magnetocrystalline anisotropy, high coercivity and low to moderate saturation magnetization, has found a variety of applications. Clusters of such nanoparticles are predicted to have revolutionary applications. Herein, we report the designed synthesis of cobalt ferrite clusters with a flower like morphology by employing a starch amylose-CTAB complex as a structure directing agent. The ability of starch amylose-CTAB to assemble nanoparticles from a centric core enabled the enhancement of the cluster diameter, leading to a ten fold increase in the T-2 relaxivity when compared to the nanoparticles. The nanoparticles were synthesized from metal-polysaccharide complexes, which led to a narrow particle size distribution, low polydispersity index and positively charged surface, all of which contributed to an enhanced R-2/R-1 value of 82.43, closer to several commercial products. Using starch as a template, along with a low concentration of CTAB, led to low cytotoxicity and high hemocompatibility. In addition, surface starch could provide easy uptake by stem cells and also be linked to light sensitive motifs for dynamic monitoring with MRI.
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    Flower shaped assembly of cobalt ferrite nanoparticles: application as T2 contrast agent in MRI
    (RSC Advances, 2013-04) Nidhin, M; Shaiju Nazeer, SS; Jayasree, RS; Kiran, MS; Nair, BU; Sreeram, KJ
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    Fluorescent nanonetworks: A novel bioalley for collagen scaffolds and Tissue Engineering
    (Scientific Reports(Nature Publishing Group)., 2014) Nidhin, M; Vedhanayagam, M; Sangeetha, S; Shaiju, SN; Jayasree, RS; Sreeram, KJ; Nair, BU
    Native collagen is arranged in bundles of aligned fibrils to withstand in vivo mechanical loads. Reproducing such a process under in vitro conditions has not met with major success. Our approach has been to induce nanolinks, during the self-assembly process, leading to delayed rather than inhibited fibrillogenesis. For this, a designed synthesis of nanoparticles - using starch as a template and a reflux process, which would provide a highly anisotropic (star shaped) nanoparticle, with large surface area was adopted. Anisotropy associated decrease in Morin temperature and superparamagnetic behavior was observed. Polysaccharide on the nanoparticle surface provided aqueous stability and low cytotoxicity. Starch coated nanoparticles was utilized to build polysaccharide - collagen crosslinks, which supplemented natural crosslinks in collagen, without disturbing the conformation of collagen. The resulting fibrillar lamellae showed a striking resemblance to native lamellae, but had a melting and denaturation temperature higher than native collagen. The biocompatibility and superparamagnetism of the nanoparticles also come handy in the development of stable collagen constructs for various biomedical applications, including that of MRI contrast agents.
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    Fluorescent nanonetworks: A novel bioalley for collagen scaffolds and Tissue Engineering
    (Scientific Reports(Nature Publishing Group)., 2014-08) Nidhin, M; Vedhanayagam, M; Sangeetha, S; Kiran, MS; Shaiju, SN; Jayasree, RS; Sreeram, KJ; Nair, BU
    Native collagen is arranged in bundles of aligned fibrils to withstand in vivo mechanical loads. Reproducing such a process under in vitro conditions has not met with major success. Our approach has been to induce nanolinks, during the self-assembly process, leading to delayed rather than inhibited fibrillogenesis. For this, a designed synthesis of nanoparticles - using starch as a template and a reflux process, which would provide a highly anisotropic (star shaped) nanoparticle, with large surface area was adopted. Anisotropy associated decrease in Morin temperature and superparamagnetic behavior was observed. Polysaccharide on the nanoparticle surface provided aqueous stability and low cytotoxicity. Starch coated nanoparticles was utilized to build polysaccharide - collagen crosslinks, which supplemented natural crosslinks in collagen, without disturbing the conformation of collagen. The resulting fibrillar lamellae showed a striking resemblance to native lamellae, but had a melting and denaturation temperature higher than native collagen. The biocompatibility and superparamagnetism of the nanoparticles also come handy in the development of stable collagen constructs for various biomedical applications, including that of MRI contrast agents.