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Magnetic polyethyleneimine (PEI) microcapsules as retrievable traps for carcinogen electrophiles formed in the
Abstract:
Semi-permeable magnetic microcapsules containing polyethyleneimine (PEI) have been developed as retrievable carcinogen traps. In vitro, the soluble core PEI and membrane both bound reactive substances of limited aqueous stability, such as from [14C]N-methyl-N-nitrosourea ([14C]NMU), and aqueous stable dyes of molecular weight up to 1000. The core/membrane location ratio of binding was dependent upon membrane characteristics of the microcapsule batch used. Microcapsules administered intragastrically to rats bound up to 0.006% of [14C]dimethylhydrazine ([14C]DMH) and 1.4% of [14C]NMU administered i.p. or intrarectally, respectively. Time-dependency of [14C]DMH binding was consistent with labelling of microcapsules within the small intestine. There were no detectable metabolites from [14C]DMH trapped within the colon, whereas binding of [14C]NMU indicated that microcapsules could bind transient species present within the colon in competition with the faecal bulk. These results indicate that this approach could be used to detect highly unstable and possibly genotoxic substances in situ, hitherto unknown, formed within the intestinal lumen.
Insights
Magnetic microcapsules loaded with polyethyleneimine (PEI) effectively trap carcinogens like [14C]NMU and [14C]DMH in vitro and in vivo. This technology shows promise for detecting unknown, unstable genotoxic substances in the gastrointestinal tract.
Area of Science:
- Biomaterials Science
- Toxicology
- Gastroenterology
Background:
- Carcinogen detection in the gastrointestinal tract is challenging due to the instability of many reactive substances.
- Polyethyleneimine (PEI) is a polymer with known binding capabilities for various compounds.
Purpose of the Study:
- To develop and evaluate semi-permeable magnetic microcapsules containing PEI as retrievable traps for carcinogens.
- To assess the in vitro and in vivo binding efficacy of these microcapsules for specific carcinogens.
Main Methods:
- Development of semi-permeable magnetic microcapsules encapsulating PEI.
- In vitro binding assays with [14C]N-methyl-N-nitrosourea ([14C]NMU) and stable dyes.
- In vivo studies in rats involving intragastric, intraperitoneal, and intrarectal administration of microcapsules with radiolabeled carcinogens ([14C]DMH and [14C]NMU).
Main Results:
- Microcapsules demonstrated binding of reactive substances ([14C]NMU) and stable dyes in vitro.
- In vivo, microcapsules bound administered [14C]DMH and [14C]NMU, with binding location correlating with administration route and time.
- No [14C]DMH metabolites were detected in the colon, but [14C]NMU binding indicated capture of transient species.
Conclusions:
- Semi-permeable magnetic microcapsules containing PEI are effective in trapping carcinogens both in vitro and in vivo.
- This approach offers a novel method for in situ detection of unstable and potentially genotoxic substances within the intestinal lumen.