title: Non-Cytotoxic Quantum Dot-Chitosan Nanogel Biosensing Probe for Potential Cancer Targeting Agent.
abstract: Quantum dot (Qdot) biosensors have consistently provided valuable information to researchers about cellular activity due to their unique fluorescent properties. Many of the most popularly used Qdots contain cadmium, posing the risk of toxicity that could negate their attractive optical properties. The design of a non-cytotoxic probe usually involves multiple components and a complex synthesis process. In this paper, the design and synthesis of a non-cytotoxic Qdot-chitosan nanogel composite using straight-forward cyanogen bromide (CNBr) coupling is reported. The probe was characterized by spectroscopy (UV-Vis, fluorescence), microscopy (Fluorescence, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering. This activatable ("OFF"/"ON") probe contains a core-shell Qdot (CdS:Mn/ZnS) capped with dopamine, which acts as a fluorescence quencher and a model drug. Dopamine capped "OFF" Qdots can undergo ligand exchange with intercellular glutathione, which turns the Qdots "ON" to restore fluorescence. These Qdots were then coated with chitosan (natural biocompatible polymer) functionalized with folic acid (targeting motif) and Fluorescein Isothiocyanate (FITC; fluorescent dye). To demonstrate cancer cell targetability, the interaction of the probe with cells that express different folate receptor levels was analyzed, and the cytotoxicity of the probe was evaluated on these cells and was shown to be nontoxic even at concentrations as high as 100 mg/L.
authors.affiliation: Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, USA. tyler.maxwell@knights.ucf.edu.|NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. tyler.maxwell@knights.ucf.edu.
authors.forename: Tyler
authors.initials: T
authors.lastname: Maxwell
authors.affiliation: NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. tahminabanu@knights.ucf.edu.|Department of Material Science and Engineering, University of Central Florida, 127600 Pegasus Drive, Engineering 1, Suite 207, Orlando, FL 32816, USA. tahminabanu@knights.ucf.edu.
authors.forename: Tahmina
authors.initials: T
authors.lastname: Banu
authors.affiliation: Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, USA. eprice2@knights.ucf.edu.|NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. eprice2@knights.ucf.edu.
authors.forename: Edward
authors.initials: E
authors.lastname: Price
authors.affiliation: NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. jeremyt@knights.ucf.edu.|Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, 6900 Lake Nona Boulevard, Orlando, FL 32827, USA. jeremyt@knights.ucf.edu.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Tharkur
authors.affiliation: NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. maria.nogueiracampos@ucf.edu.|Institute of Science and Technology, Federal University of Alfenas, Rodovia José Aurélio Vilela, 11999, Poços de Caldas, MG 37715-400, Brazil. maria.nogueiracampos@ucf.edu.
authors.forename: Maria Gabriela Nogueira
authors.initials: MG
authors.lastname: Campos
authors.affiliation: Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, USA. andre@ucf.edu.|NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. andre@ucf.edu.|Department of Material Science and Engineering, University of Central Florida, 127600 Pegasus Drive, Engineering 1, Suite 207, Orlando, FL 32816, USA. andre@ucf.edu.|College of Optics and Photonics, University of Central Florida, P.O. Box 162700, Orlando, FL 32816, USA. andre@ucf.edu.
authors.forename: Andre
authors.initials: A
authors.lastname: Gesquiere
authors.affiliation: Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, USA. swadeshmukul.santra@ucf.edu.|NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA. swadeshmukul.santra@ucf.edu.|Department of Material Science and Engineering, University of Central Florida, 127600 Pegasus Drive, Engineering 1, Suite 207, Orlando, FL 32816, USA. swadeshmukul.santra@ucf.edu.|Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, 6900 Lake Nona Boulevard, Orlando, FL 32827, USA. swadeshmukul.santra@ucf.edu.
authors.forename: Swadeshmukul
authors.initials: S
authors.lastname: Santra
keywords: biosensor; cancer; chitosan; drug delivery; nanogel; quantum dot