title: Microencapsulating hepatocytes.
abstract: BACKGROUND
  Because standardization of the cell microencapsulation procedure has not yet been achieved, we performed hepatocyte microencapsulation using alginate (ALG)-poly-l-lysine (PLL)-ALG (APA) polymer.
  
  
  METHODS
  Hepatocytes were microencapsulated using a binozzle air-jet droplet generator. Our study aims were to: (1) clarify how ALG concentration affects the quality of ALG beads; (2) determine how the PLL concentration affects the quality of microcapsules (MCs); (3) ascertain the influence of liquefaction time by sodium citrate (SC) on the quality of the MCs; (4) and clarify how temperature and solution pH, respectively, affect the viability of the hepatocytes inside the MCs.
  
  
  RESULTS
  The concentration of ALG must be > or = 3% (w/v) to generate droplets with satisfactory homogeneity in size and roundness (P < .01). The total quantity of PLL molecules is the essential component for MCs (P < .01). As our results show, the numeric ratio of PLL (milligrams) to MCs (milliliters) is roughly 25:1. SC incubation for 8 minutes resulted in the proper thickness of the MC wall; however, the time varied according to the size of the MCs (P < .05). Temperature and pH, although both difficult to control, exerted great influences on cell viability: 4 degrees C and pH 7.2 were found to be optimal by this study (P < .05).
  
  
  CONCLUSIONS
  Concentrations of ALG and PLL exerted decisive effects on the quality and strength of MCs. Higher concentrations were suggested. Because temperature and pH greatly affected cell viability, they must be properly monitored.
authors.affiliation: Department of General Surgery, First Clinical Hospital of Harbin Medical University, Harbin, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.forename: H C
authors.initials: HC
authors.lastname: Jiang
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.forename: S H
authors.initials: SH
authors.lastname: Pan
authors.forename: Y D
authors.initials: YD
authors.lastname: Li
mesh_terms: D000464:Alginates; D000818:Animals; D002214:Capsules; D017690:Cell Transplantation / Q000379:methods; D022781:Hepatocytes / Q000166:cytology* / Q000502:physiology*; D008297:Male; D011107:Polylysine / Q000031:analogs & derivatives*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000464:Alginates; D002214:Capsules; C051546:alginate-polylysine-alginate; D011107:Polylysine