title: Fluorescent cadmium telluride quantum dots embedded chitosan nanoparticles: a stable, biocompatible preparation for bio-imaging.
abstract: Fluorescent cadmium telluride quantum dots (CdTe QDs) are an optically attractive option for bioimaging, but are known to display high cytotoxicity. Nanoparticles synthesized from chitosan, a natural biopolymer of β 1-4 linked glucosamine, display good biocompatibility and cellular uptake. A facile, green synthetic strategy has been developed to embed green fluorescent cadmium telluride quantum dots (CdTe QDs) in biocompatible CNPs to obtain a safer preparation than 'as is' QDs. High-resolution transmission electron microscopy showed the crystal lattice corresponding to CdTe QDs embedded in CNPs while thermogravimetry confirmed their polymeric composition. Electrostatic interactions between thiol-capped QDs (4 nm, -57 mV) and CNPs (~300 nm, +38 mV) generated CdTe QDs-embedded CNPs that were stable up to three months. Further, viability of NIH3T3 mouse fibroblast cells in vitro increased in presence of QDs-embedded CNPs as compared to bare QDs. At the highest concentration (10 μg/ml), the former shows 34 and 39% increase in viability at 24 and 48 h, respectively, as compared to the latter. This shows that chitosan nanoparticles do not release the QDs up to 48 h and do not cause extended toxicity. Furthermore, hydrolytic enzymes such as lysozyme and chitinase did not degrade chitosan nanoparticles. Moreover, QDs-embedded CNPs show enhanced internalization in NIH3T3 cells as compared to bare QDs. This method offers ease of synthesis and handling of stable, luminescent, biocompatible CdTe QDs-embedded CNPs with a favorable toxicity profile and better cellular uptake with potential for bioimaging and targeted detection of cellular components.
authors.affiliation: a Centre for Nanobioscience , Agharkar Research Institute , GG Agarkar Road, Pune 411004 , India.
authors.forename: Vandana
authors.initials: V
authors.lastname: Ghormade
authors.forename: Haribhau
authors.initials: H
authors.lastname: Gholap
authors.forename: Sonia
authors.initials: S
authors.lastname: Kale
authors.forename: Vaishnavi
authors.initials: V
authors.lastname: Kulkarni
authors.forename: Suresh
authors.initials: S
authors.lastname: Bhat
authors.forename: Kishore
authors.initials: K
authors.lastname: Paknikar
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D001692:Biological Transport; D019187:Cadmium Compounds / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry* / Q000378:metabolism; D004355:Drug Stability; D005456:Fluorescent Dyes / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D041681:NIH 3T3 Cells; D055620:Optical Phenomena; D045663:Quantum Dots / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D012997:Solvents; D014867:Water; D048271:Chitosan; D013691:Tellurium; C028337:cadmium telluride
keywords: CdTe quantum dots; biocompatible; bioimaging; chitosan nanoparticles; toxicity