title: Hybrid shell engineering of animal cells for immune protections and regulation of drug delivery: towards the design of "artificial organs".
abstract: BACKGROUND
  With the progress in medicine, the average human life expectancy is continuously increasing. At the same time, the number of patients who require full organ transplantations is augmenting. Consequently, new strategies for cell transplantation are the subject of great interest.
  
  
  RESULTS
  This work reports the design, the synthesis and the characterisation of robust and biocompatible mineralised beads composed of two layers: an alginate-silica composite core and a Ca-alginate layer. The adequate choice of materials was achieved through cytotoxicity LDH release measurement and in vitro inflammatory assay (IL-8) to meet the biocompatibility requirements for medical purpose. The results obtained following this strategy provide a direct proof of the total innocuity of silica and alginate networks for human cells as underscored by the non-activation of immune defenders (THP-1 monocytes). The accessible pore size diameter of the mineralised beads synthesized was estimated between 22 and 30 nm, as required for efficient immuno-isolation without preventing the diffusion of nutrients and metabolites. The model human cells, HepG2, entrapped within these hybrid beads display a high survival rate over more than six weeks according to the measurements of intracellular enzymatic activity, respiration rate, as well as the "de novo" biosynthesis and secretion of albumin out of the beads.
  
  
  CONCLUSIONS
  The current study shows that active mammalian cells can be protected by a silica-alginate hybrid shell-like system. The functionality of the cell strain can be maintained. Consequently, cells coated with an artificial and a biocompatible mineral shell could respond physiologically within the human body in order to deliver therapeutic agents in a controlled fashion (i.e. insulin), substituting the declining organ functions of the patient.
authors: Laboratory of Inorganic Materials Chemistry, Department of Chemistry, The University of Namur (FUNDP), Namur, Belgium.
authors: Philippe
authors: P
authors: Dandoy
authors: Christophe F
authors: CF
authors: Meunier
authors: Carine
authors: C
authors: Michiels
authors: Bao-Lian
authors: BL
authors: Su
mesh_terms: D000418:Albumins / Q000378:metabolism; D000464:Alginates / Q000494:pharmacology; D000818:Animals; D001187:Artificial Organs; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D018914:Cells, Immobilized / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004058:Diffusion / Q000187:drug effects; D016503:Drug Delivery Systems / Q000379:methods*; D005456:Fluorescent Dyes / Q000378:metabolism; D020723:Glucuronic Acid / Q000494:pharmacology; D056945:Hep G2 Cells; D006603:Hexuronic Acids / Q000494:pharmacology; D006801:Humans; D007109:Immunity; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D016209:Interleukin-8 / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010101:Oxygen Consumption / Q000187:drug effects; D012822:Silicon Dioxide / Q000494:pharmacology; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000418:Albumins; D000464:Alginates; D001672:Biocompatible Materials; D005456:Fluorescent Dyes; D006603:Hexuronic Acids; D016209:Interleukin-8; D012822:Silicon Dioxide; D020723:Glucuronic Acid