Artificial cell microcapsule for oral delivery of live bacterial cells for therapy: design, preparation, and in-vitro characterization.
OBJECTIVE
Bacterial cells can be engineered to synthesize a wide array of disease modifying substrates such as cytokines, vaccines and antibodies; however, their use as an orally delivered therapeutic is limited by poor gastrointestinal (GI) survival and instigation of immunogenic response. Artificial cell microcapsules have been well studied as a means to overcome such problems, however, presently obtainable microcapsules have limitations. This study summarizes a novel microcapsule design specifying its preparation and GI stability in-vitro.


METHODS
Multilayer APPPA microcapsules were designed, prepared and characterized in-vitro for bacterial cell oral delivery using Lactobacillus reuteri cells as a model. Microcapsule structural integrity, mechanical stability, and GI survival studies were performed in simulated gastric (SGF) and intestinal (SIF) fluids in various pH conditions at 37.2 degrees C and compared with presently available alginate/poly-l-lysine/alginate (APA) microcapsules. HPLC was used for the microcapsule membrane permeability study.


RESULTS
Results show that APPPA microcapsules can be prepared for bacterial cell encapsulation and are stable in simulated GI conditions. No microcapsule damage was reported when exposed to SGF and SIF for 12 hours at 250 rpm mechanical shaking at 37.2 degrees C. In addition, 93.2+/-2.3% and 98.9+/-0.6% of microcapsules were undamaged after 24 hours in SGF and SIF respectively. Microcapsule pH stability results show that 92.8+/-3.1% of microcapsules remained intact at pH 1, 3, 5, and 7 and no damage was observed at pH 9.0 when challenged for 24 hours. When exposed for 3 hours with 250 rpm shaking at 37.2 degrees C, no damage of the microcapsules in SGF and SIF at pH, 1,3,5,7, and 9 was observed. Compared to APA microcapsules, APPPA membranes showed superior GI stability and permeability for cell encapsulation.


CONCLUSIONS
Novel APPPA microcapsules have superior features for oral delivery of live bacterial cells and they can be used for various clinical applications. However, further study such as membrane permeability, cytotoxicity, immune protection capacity, and suitability for live bacterial cell oral delivery in-vivo is required.
Ouyang
Wei
W
Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, Quebec, Canada.
Chen
Hongmei
H
Jones
Mitchell L
ML
Metz
Terrence
T
Haque
Tasima
T
Martoni
Christopher
C
Prakash
Satya
S
D000464:Alginates / Q000737:chemistry; D000818:Animals; D002214:Capsules / Q000008:administration & dosage / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers; D016503:Drug Delivery Systems; D015195:Drug Design; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007778:Lactobacillus / Q000378:metabolism; D008099:Liver / Q000382:microbiology; D010316:Particle Size; D010368:Pectins / Q000737:chemistry; D010539:Permeability; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D011107:Polylysine / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000378:metabolism
D000464:Alginates; D002214:Capsules; D004337:Drug Carriers; D006603:Hexuronic Acids; D004364:Pharmaceutical Preparations; D011107:Polylysine; D012710:Serum Albumin, Bovine; D010368:Pectins; D020723:Glucuronic Acid