title: Composite Porous Silicon-Silver Nanoparticles as Theranostic Antibacterial Agents.
abstract: A theranostic nanoparticle with biochemically triggered antibacterial activity is demonstrated. Metallic silver is deposited onto porous silicon nanoparticles (pSiNPs) by galvanic displacement. When aqueous diaminesilver ([Ag(NH3)2]+) is used as a silver source, the pSiNPs template the crystalline silver as small (mean diameter 13 nm) and well-dispersed nanoparticles embedded within and on the larger (100 nm) pSiNPs. The silver nanoparticles (AgNPs) quench intrinsic photoluminescence (PL) from the porous silicon (pSi) matrix. When exposed to an aqueous oxidant, the AgNPs are preferentially etched, Ag+is released into solution, and PL from the pSi carrier is recovered. The released Ag+results in 90% killing of (Gram-negative) Pseudomonas aeruginosa and (Gram-positive) Staphylococcus aureus within 3 h. When conjugated with the TAT peptide (sequence RKKRRQRRR), the silver-deposited porous silicon (pSi-Ag) nanocomposite shows distinct targeting toward S. aureus bacteria in vitro. Intravenously injected TAT-conjugated pSi-Ag nanoparticles accumulate in the liver, spleen, and lungs of mice, and the in vivo release of Ag+and recovery of PL from pSi are demonstrated by the subsequent intraperitoneal administration of a hexacyanoferrate solution. The released Ag+leads to a significant bacterial count reduction in liver tissue relative to the control. The data demonstrate the feasibility of the targeted and triggered delivery of antibacterial Ag+ion in vivo, using a self-reporting and nontoxic nanocarrier.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Taeho
authors.initials: T
authors.lastname: Kim
authors.affiliation: Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States.|Center for Nanomedicine and Department of Cell, Molecular and Developmental Biology, University of California, Santa Barbara , Santa Barbara, California 93106-9610, United States.
authors.forename: Gary B
authors.initials: GB
authors.lastname: Braun
authors.affiliation: Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: She
authors.affiliation: Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States.
authors.forename: Sazid
authors.initials: S
authors.lastname: Hussain
authors.affiliation: Cancer Research Center, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States.|Center for Nanomedicine and Department of Cell, Molecular and Developmental Biology, University of California, Santa Barbara , Santa Barbara, California 93106-9610, United States.
authors.forename: Erkki
authors.initials: E
authors.lastname: Ruoslahti
authors.affiliation: 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: D000818:Animals; D000900:Anti-Bacterial Agents; D053768:Metal Nanoparticles; D051379:Mice; D008826:Microbial Sensitivity Tests; D012825:Silicon; D012834:Silver; D013211:Staphylococcus aureus; D000068936:Theranostic Nanomedicine
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D012825:Silicon
keywords: Pseudomonas aeruginosa; Staphylococcus aureus; antibacterial; controlled-release drug delivery; electroless deposition; photoluminescence quenching; plasmonic nanoparticles; time-gated photoluminescence