Browsing by Author "Vijayan, VM"

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    Octreotide-conjugated fluorescent PEGylated polymeric nanogel for theranostic applications
    (Materials Science and Engineering, 2017-03) Vijayan, VM; Shenoy, SJ; Jayabalan, M
    Targeted nanocarriers can significantly increase the efficiency of therapeutic formulations by ensuring the site specific delivery of the cargo. Here in, we report a novel actively targeted fluorescent nanogel, PMB-OctN, based on photoluminescent comacromer [PEG-maleic acid-4 aminobenzoic acid], diethylene glycoldimethacrylate and octreotide. The nanogel has spherical morphology with average particle size around 40 nm. The PMB-OctN can load 78% of anticancer drug and release for 5 days and beyond in a sustained way. The studies on drug delivery of doxorubicin from PMB-OctN carried out with cervical cancer cells. Hela revealed appreciable therapeutic capability. The studies on cellular uptake of the nanogel revealed increased cellular uptake when compared to the nontargeted nanogel. The study on fluorescence bioimaging of the PMB-OctN in mice has demonstrated near-IR imaging capability. Then biodistribution studies of the PMB-OctN in mice have also revealed longer in vivo circulation lifetime. Taken together, these results suggest that the synthesized actively targeted nanogel, PMB-OctN stands as a promising candidate for theranostic applications. As octreotide based therapeutic formulation are already used in clinics, this newly reported strategy of near-IR fluorescence labeling of octreotide has important clinical relevance.
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    Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2015) Vijayan, VM; Komeri, R; Victor, SP; Muthu, J
    We report a novel multi-modal biodegradable photoluminescent comacromer [poly(propylene fumarate)-PEG-glycine] (PLM) having excitation-dependent fluorescence (EDF) for biomedical applications. The photoluminescence of the synthesized PLM in aqueous and solid state condition, fluorescence life time and photo stability were evaluated. Hydrogels and nanogels were prepared from the PLM by cross linking with acrylic acid. Nanogels exhibited spherical morphology with a particle size of 100 nm as evaluated by transmission electron microscopy (TEM). In vitro cytotoxic and hemolytic studies revealed cytocompatibility. Furthermore, cellular imaging of nanogels on L929 fibroblast and Hela cell lines revealed EDF characteristics. We hypothesize that the EDF characteristics of the synthesized PLM may be attributed to the presence of n-pi* interactions of the hydroxyl oxygen atoms of PEG with carbonyl groups of the ester linkages. Taken together, our results indicate that the synthesized PEG-based comacromer can serve as biocompatible fluorophores for various biomedical applications. More importantly, the facile way of synthesizing fluorescent polymers based on PEG with EDF characteristics demonstrated in this work can pave the way for developing more novel biocompatible fluorophores with wide range of biomedical applications. (C) 2015 Elsevier B.V. All rights reserved.
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    Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications.
    (Colloids and Surfaces B: Biointerfaces, 2015-09) Vijayan, VM; Komeri, R; Victor, SP; Muthu, J
    We report a novel multi-modal biodegradable photoluminescent comacromer [poly(propylene fumarate)-PEG-glycine] (PLM) having excitation-dependent fluorescence (EDF) for biomedical applications. The photoluminescence of the synthesized PLM in aqueous and solid state condition, fluorescence life time and photo stability were evaluated. Hydrogels and nanogels were prepared from the PLM by cross linking with acrylic acid. Nanogels exhibited spherical morphology with a particle size of 100 nm as evaluated by transmission electron microscopy (TEM). In vitro cytotoxic and hemolytic studies revealed cytocompatibility. Furthermore, cellular imaging of nanogels on L929 fibroblast and Hela cell lines revealed EDF characteristics. We hypothesize that the EDF characteristics of the synthesized PLM may be attributed to the presence of n–π* interactions of the hydroxyl oxygen atoms of PEG with carbonyl groups of the ester linkages. Taken together, our results indicate that the synthesized PEG-based comacromer can serve as biocompatible fluorophores for various biomedical applications. More importantly, the facile way of synthesizing fluorescent polymers based on PEG with EDF characteristics demonstrated in this work can pave the way for developing more novel biocompatible fluorophores with wide range of biomedical applications.
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    Stimulus responsive nanogel with innate near IR fluorescent capability for drug delivery and bioimaging
    (Colloids and Surfaces B: Biointerfaces, 2016-06) Vijayan, VM; Shenoy, SJ; Victor, SP; Muthu, J
    A brighter, non toxic and biocompatible optical imaging agent is one of the major quests of biomedical research. Here in, we report a photoluminescent comacromer [PEG-poly(propylene fumarate)-citric acid-glycine] and novel stimulus (pH) responsive nanogel endowed with excitation wavelength dependent fluorescence (EDF) for combined drug delivery and bioimaging applications. The comacromer when excited at different wavelengths in visible region from 400 nm to 640 nm exhibits fluorescent emissions from 510 nm to 718 nm in aqueous condition. It has high Stokes shift (120 nm), fluorescent lifetime (7 nanoseconds) and quantum yield (50%). The nanogel, C-PLM-NG, prepared with this photoluminescent comacromer and N,N-dimethyl amino ethylmethacrylate (DMEMA) has spherical morphology with particle size around 100 nm and 180 nm at pH 7.4 (physiological) and 5.5 (intracellular acidic condition of cancer cells) respectively. The studies on fluorescence characteristics of C-PLM NG in aqueous condition reveal large red-shift with emissions from 523 nm to 700 nm for excitations from 460 nm to 600 nm ascertaining the EDF characteristics. Imaging the near IR emission with excitation at 535 nm was accomplished using cut-off filters. The nanogel undergoes pH responsive swelling and releases around 50% doxorubicin (DOX) at pH 5.5 in comparison with 15% observed at pH 7.4. The studies on in vitro cytotoxicity with MTT assay and hemolysis revealed that the present nanogel is non-toxic. The DOX-loaded C-PLM-NG encapsulated in Hela cells induces lysis of cancer cells. The inherent EDF characteristics associated with C-PLM NG enable cellular imaging of Hela cells. The studies on biodistribution and clearance mechanism of C-PLM-NG from the body of mice reveal bioimaging capability and safety of the present nanogel. This is the first report on a polymeric nanogel with innate near IR emissions for bioimaging applications.