title: Influence of charge on FITC-BSA-loaded chondroitin sulfate-chitosan nanoparticles upon cell uptake in human Caco-2 cell monolayers.
abstract: METHODS
  Chondroitin sulfate-chitosan (ChS-CS) nanoparticles and positively and negatively charged fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA)-loaded ChS-CS nanoparticles were prepared and characterized. The properties of ChS-CS nanoparticles, including cellular uptake, cytotoxicity, and transepithelial transport, as well as findings on field emission-scanning electron microscopy, transmission electron microscopy, and confocal laser scanning microscopy were evaluated in human epithelial colorectal adenocarcinoma (Caco-2) fibroblasts. ChS-CS nanoparticles with a mean particle size of 250 nm and zeta potentials ranging from -30 to +18 mV were prepared using an ionic gelation method.
  
  
  RESULTS
  Standard cell viability assays demonstrated that cells incubated with ChS-CS and FITC-BSA-loaded ChS-CS nanoparticles remained more than 95% viable at particle concentrations up to 0.1 mg/mL. Endocytosis of nanoparticles was confirmed by confocal laser scanning microscopy and measured by flow cytometry. Ex vivo transepithelial transport studies using Caco-2 cells indicated that the nanoparticles were effectively transported into Caco-2 cells via endocytosis. The uptake of positively charged FITC-BSA-loaded ChS-CS nanoparticles across the epithelial membrane was more efficient than that of the negatively charged nanoparticles.
  
  
  CONCLUSIONS
  The ChS-CS nanoparticles fabricated in this study were effectively endocytosed by Caco-2 fibroblasts without significant cytotoxicity at high nanoparticle concentrations. ChS-CS nanoparticles represent a potential novel delivery system for the transport of hydrophilic macromolecules.
authors.affiliation: Biomedical Engineering Program, Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taiwan, Republic of China.
authors.forename: Chieh-shen
authors.initials: CS
authors.lastname: Hu
authors.forename: Chiao-hsi
authors.initials: CH
authors.lastname: Chiang
authors.forename: Po-da
authors.initials: PD
authors.lastname: Hong
authors.forename: Ming-kung
authors.initials: MK
authors.lastname: Yeh
mesh_terms: D000327:Adsorption; D018938:Caco-2 Cells; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism*; D048271:Chitosan / Q000737:chemistry*; D002809:Chondroitin Sulfates / Q000737:chemistry*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry*; D006801:Humans; D053769:Nanocapsules / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000493:pharmacokinetics*; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D053769:Nanocapsules; D012710:Serum Albumin, Bovine; D002809:Chondroitin Sulfates; D048271:Chitosan; D016650:Fluorescein-5-isothiocyanate