title: A physical model for the size-dependent cellular uptake of nanoparticles modified with cationic surfactants.
abstract: BACKGROUND
  The aim of this work was to improve oral bioavailability. The uptake of a series of quaternary ammonium salt didodecyl dimethylammonium bromide (DMAB)-modified nanoparticles (with uniform sizes ranging from 50 nm to 300 nm) into heterogeneous human epithelial colorectal adenocarcinoma cells (Caco-2) and human colon adenocarcinoma cells (HT-29) was investigated.
  
  
  METHODS
  Coumarin-6 (C6) loaded poly (lactide-co-glycolide) (PLGA) nanoparticles were prepared with DMAB using the emulsion solvent diffusion method. The physicochemical properties and cellular uptake of these nanoparticles were studied. Deserno's model was applied to explain the experimental observations.
  
  
  RESULTS
  The results showed that the surface modification of PLGA nanoparticles with DMAB notably improved the cellular uptake. The cellular uptake was size-dependent and had an optimal particle size of 100 nm. The experimental data was integrated numerically, and was in agreement with the theoretical model.
  
  
  CONCLUSIONS
  These results indicated that the interactions between the charged nanoparticles and the cells resulted from various forces (eg, electrostatic forces, hydrophobic forces, bending and stretching forces, and limited receptor-mediated endocytosis), and the uptake of the nanoparticles occurred as a result of competition.
authors: Clinical Pharmacology Research Center, Ningbo Urinary and Renal Diseases Hospital, Ningbo, China.
authors: Airen
authors: A
authors: Xu
authors: Mingfei
authors: M
authors: Yao
authors: Guangkui
authors: G
authors: Xu
authors: Jingyan
authors: J
authors: Ying
authors: Weicheng
authors: W
authors: Ma
authors: Bo
authors: B
authors: Li
authors: Yi
authors: Y
authors: Jin
mesh_terms: D018938:Caco-2 Cells; D002412:Cations / Q000737:chemistry; D003374:Coumarins / Q000737:chemistry / Q000493:pharmacokinetics; D004655:Emulsions; D019073:HT29 Cells; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000493:pharmacokinetics; D013329:Structure-Activity Relationship; D013501:Surface-Active Agents / Q000737:chemistry* / Q000493:pharmacokinetics; D013844:Thiazoles / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D002412:Cations; D003374:Coumarins; D004655:Emulsions; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D013844:Thiazoles; C517282:coumarin 6; C046112:didodecyldimethylammonium; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid