title: Reaction of chitosan with genipin and its fluorogenic attributes for potential microcapsule membrane characterization.
abstract: This study investigates the fluorogenic characteristics of the chitosan-genipin reaction for applications in microencapsulation research. Results showed that the chitosan-genipin reaction generated a colored and fluorescent product, with optimal excitation and emission wavelengths at 369 and 470 nm, respectively. Furthermore, it was found that reaction conditions affected the fluorescence intensity of the product. Mixture at the ratio of 4:1 (chitosan: genipin by weight) fluoresced the most. It also fluoresced stronger if the reaction occurred at higher temperature, with the intensity of 10.4 x 10(5) CPS at 37 degrees C, 5.9 x 10(5) CPS at 20 degrees C, and 2.5 x 10(5) CPS at 4 degrees C. As well, the fluorescence of the mixture developed gradually over time, attaining the emission maxima of 2.9 x 10(5), 7.6 x 10(5), and 10.0 x 10(5) CPS in 1, 6, and 18 h, respectively. Chitosan-coated alginate microcapsules were prepared without prior labeling, to which subsequent genipin treatment was applied in order to examine the potential of using genipin in microcapsule characterization. Chitosan bound to the alginate beads interacted with genipin, from which the resultant fluorescent signals allowed for clear visualization of the chitosan coating under confocal laser scanning microscopy. The relative fluorescence intensity across the chitosan membrane was found to be considerably higher than the controls (175 vs. 50). The membrane thickness measured was 29.2 +/- 7.3 microm. These findings demonstrate a convenient and effective way of characterizing chitosan-based microcapsules using genipin as a fluorogenic marker, a technique that will be useful in microcapsule research and other biomedical applications.
authors.affiliation: Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, 3775 University Street, Montreal, Quebec H3A 2B4, Canada.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Ouyang
authors.forename: Bisi
authors.initials: B
authors.lastname: Lawuyi
authors.forename: Christopher
authors.initials: C
authors.lastname: Martoni
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
mesh_terms: D002214:Capsules / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D057889:Iridoid Glycosides; D039823:Iridoids; D018613:Microscopy, Confocal; D011714:Pyrans / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D002214:Capsules; D020099:Coated Materials, Biocompatible; D005456:Fluorescent Dyes; D057889:Iridoid Glycosides; D039823:Iridoids; D011714:Pyrans; D048271:Chitosan; C007834:genipin