title: Synthesis, characterization and biocompatibility of cadmium sulfide nanoparticles capped with dextrin for in vivo and in vitro imaging application.
abstract: BACKGROUND
  The safe use in biomedicine of semiconductor nanoparticles, also known as quantum dots (QDs), requires a detailed understanding of the biocompatibility and toxicity of QDs in human beings. The biological characteristics and physicochemical properties of QDs entail new challenges regarding the management of potential adverse health effects following exposure. At certain concentrations, the synthesis of semiconductor nanoparticles of CdS using dextrin as capping agent, at certain concentration, to reduce their toxicity and improves their biocompatibility.
  
  
  RESULTS
  This study successfully synthesized and characterized biocompatible dextrin-coated cadmium sulfide nanoparticles (CdS-Dx/QDs). The results show that CdS-Dx/QDs are cytotoxic at high concentrations (>2 μg/mL) in HepG2 and HEK293 cells. At low concentrations (<1 μg/mL), CdS-Dx/QDs were not toxic to HepG2 or HeLa cells. CdS-Dx nanoparticles only induced cell death by apoptosis in HEK293 cells at 1 μg/mL concentrations. The in vitro results showed that the cells efficiently took up the CdS-Dx/QDs and this resulted in strong fluorescence. The subcellular localization of CdS-Dx/QDs were usually small and apparently unique in the cytoplasm in HeLa cells but, in the case of HEK293 cells it were more abundant and found in cytoplasm and the nucleus. Animals treated with 100 μg/kg of CdS-Dx/QDs and sacrificed at 3, 7 and 18 h showed a differential distribution in their organs. Intense fluorescence was detected in lung and kidney, with moderate fluorescence detected in liver, spleen and brain. The biocompatibility and toxicity of CdS-Dx/QDs in animals treated daily with 100 μg/kg for 1 week showed the highest level of fluorescence in kidney, liver and brain. Less fluorescence was detected in lung and spleen. There was also evident presence of fluorescence in testis. The histopathological and biochemical analyses showed that CdS-Dx/QDs were non-toxic for rodents.
  
  
  CONCLUSIONS
  The in vitro and in vivo studies confirmed the effective cellular uptake and even distribution pattern of CdS-Dx/QDs in tissues. CdS-Dx/QDs were biocompatible with tissues from rodents. The CdS-Dx/QDs used in this study can be potentially used in bio-imaging applications.
authors.affiliation: Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Cuernavaca, 62210, Mexico. jareyes@uaem.mx.
authors.forename: Jorge
authors.initials: J
authors.lastname: Reyes-Esparza
authors.affiliation: Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Cuernavaca, 62210, Mexico. martinezm@yahoo.com.
authors.forename: Alberto
authors.initials: A
authors.lastname: Martínez-Mena
authors.affiliation: Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Cuernavaca, 62210, Mexico. sanchag@yahoo.com.
authors.forename: Ivonne
authors.initials: I
authors.lastname: Gutiérrez-Sancha
authors.affiliation: Departamento de Física, CINVESTAV-I.P.N., Apartado Postal 14-740, 07000, Mexico, D.F., Mexico. patricia@fis.cinvestav.mx.
authors.forename: Patricia
authors.initials: P
authors.lastname: Rodríguez-Fragoso
authors.affiliation: Departamento de Física, CINVESTAV-I.P.N., Apartado Postal 14-740, 07000, Mexico, D.F., Mexico. bato@fis.cinvestav.mx.
authors.forename: Gerardo Gonzalez
authors.initials: GG
authors.lastname: de la Cruz
authors.affiliation: Departamento de Bioquímica, CINVESTAV-I.P.N., Apartado Postal 14-740, 07000, Mexico, D.F., Mexico. rmflores@cinvestav.mx.
authors.forename: R
authors.initials: R
authors.lastname: Mondragón
authors.affiliation: Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Cuernavaca, 62210, Mexico. mrodriguezf@uaem.mx.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Rodríguez-Fragoso
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D019187:Cadmium Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D016923:Cell Death; D002470:Cell Survival; D003912:Dextrins / Q000138:chemical synthesis* / Q000737:chemistry*; D003952:Diagnostic Imaging / Q000379:methods*; D004705:Endocytosis; D057809:HEK293 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D045663:Quantum Dots / Q000737:chemistry; D013440:Sulfides / Q000138:chemical synthesis* / Q000737:chemistry*; D014018:Tissue Distribution
chemical_list: D001672:Biocompatible Materials; D019187:Cadmium Compounds; D003912:Dextrins; D013440:Sulfides; C034939:cadmium sulfide