title: Protection and Delivery of Anthelmintic Protein Cry5B to Nematodes Using Mesoporous Silicon Particles.
abstract: The ability of nano- and microparticles of partially oxidized mesoporous silicon (pSi) to sequester, protect, and deliver the anthelmintic pore-forming protein Cry5B to nematodes is assessed in vitro and in vivo. Thermally oxidized pSi particles are stable under gastric conditions and show relatively low toxicity to nematodes. Fluorescence images of rhodamine-labeled pSi particles within the nematodes Caenorhabditis elegans and Ancylostoma ceylanicum show that ingestion is dependent on particle size: particles of a 0.4 ± 0.2 μm size are noticeably ingested by both species within 2 h of introduction in vitro, whereas 5 ± 2 μm particles are excluded from C. elegans but enter the pharynx region of A. ceylanicum after 24 h. The anthelmintic protein Cry5B, a pore-forming crystal (Cry) protein derived from Bacillus thuringiensis, is incorporated into the pSi particles by aqueous infiltration. Feeding of Cry5B-loaded pSi particles to C. elegans leads to significant intoxication of the nematode. Protein-loaded particles of size 0.4 μm display the highest level of in vitro toxicity toward C. elegans on a drug-mass basis. The porous nanostructure protects Cry5B from hydrolytic and enzymatic (pepsin) degradation in simulated gastric fluid (pH 1.2) for time periods up to 2 h. In vivo experiments with hookworm-infected hamsters show no significant reduction in worm burden with the Cry5B-loaded particles, which is attributed to slow release of the protein from the particles and/or short residence time of the particles in the duodenum of the animal.
authors.affiliation: †Materials Science and Engineering, ‡Section of Cell and Development Biology, and §Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Chia-Chen
authors.initials: CC
authors.lastname: Wu
authors.affiliation: †Materials Science and Engineering, ‡Section of Cell and Development Biology, and §Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: †Materials Science and Engineering, ‡Section of Cell and Development Biology, and §Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Melanie
authors.initials: M
authors.lastname: Miller
authors.affiliation: †Materials Science and Engineering, ‡Section of Cell and Development Biology, and §Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Raffi V
authors.initials: RV
authors.lastname: Aroian
authors.affiliation: †Materials Science and Engineering, ‡Section of Cell and Development Biology, and §Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sailor
mesh_terms: D000722:Ancylostoma / Q000187:drug effects; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000187:drug effects; D006224:Cricetinae / Q000469:parasitology; D004731:Endotoxins / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D006460:Hemolysin Proteins / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D049329:Nanostructures / Q000008:administration & dosage / Q000737:chemistry; D009348:Nematoda / Q000187:drug effects*; D021261:Parasitic Sensitivity Tests; D010316:Particle Size; D016062:Porosity; D012825:Silicon / Q000008:administration & dosage* / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D012825:Silicon
keywords: A. ceylanicum; Bacillus thuringiensis (Bt); C. elegans; crystal protein; hookworm; oral drug delivery; porous silicon