title: Preparation and in vitro antimicrobial activity of silver-bearing degradable polymeric nanoparticles of polyphosphoester-block-poly(L-lactide).
abstract: The development of well-defined polymeric nanoparticles (NPs) as delivery carriers for antimicrobials targeting human infectious diseases requires rational design of the polymer template, an efficient synthetic approach, and fundamental understanding of the developed NPs, e.g., drug loading/release, particle stability, and other characteristics. Herein, we developed and evaluated the in vitro antimicrobial activity of silver-bearing, fully biodegradable and functional polymeric NPs. A series of degradable polymeric nanoparticles (dNPs), composed of phosphoester and L-lactide and designed specifically for silver loading into the hydrophilic shell and/or the hydrophobic core, were prepared as potential delivery carriers for three different types of silver-based antimicrobials-silver acetate or one of two silver carbene complexes (SCCs). Silver-loading capacities of the dNPs were not influenced by the hydrophilic block chain length, loading site (i.e., core or shell), or type of silver compound, but optimization of the silver feed ratio was crucial to maximize the silver loading capacity of dNPs, up to ca. 12% (w/w). The release kinetics of silver-bearing dNPs revealed 50% release at ca. 2.5-5.5 h depending on the type of silver compound. In addition, we undertook a comprehensive evaluation of the rates of hydrolytic or enzymatic degradability and performed structural characterization of the degradation products. Interestingly, packaging of the SCCs in the dNP-based delivery system improved minimum inhibitory concentrations up to 70%, compared with the SCCs alone, as measured in vitro against 10 contemporary epidemic strains of Staphylococcus aureus and eight uropathogenic strains of Escherichia coli. We conclude that these dNP-based delivery systems may be beneficial for direct epithelial treatment and/or prevention of ubiquitous bacterial infections, including those of the skin and urinary tract.
authors.affiliation: Departments of Chemistry, Chemical Engineering, and Materials Science and Engineering, and Laboratory for Synthetic-Biologic Interactions, Texas A&M University , P.O. Box 30012, 3255 TAMU, College Station, Texas 77842, United States.
authors.forename: Young H
authors.initials: YH
authors.lastname: Lim
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Tiemann
authors.forename: Gyu Seong
authors.initials: GS
authors.lastname: Heo
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Wagers
authors.forename: Yohannes H
authors.initials: YH
authors.lastname: Rezenom
authors.forename: Shiyi
authors.initials: S
authors.lastname: Zhang
authors.forename: Fuwu
authors.initials: F
authors.lastname: Zhang
authors.forename: Wiley J
authors.initials: WJ
authors.lastname: Youngs
authors.forename: David A
authors.initials: DA
authors.lastname: Hunstad
authors.forename: Karen L
authors.initials: KL
authors.lastname: Wooley
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D015195:Drug Design; D004926:Escherichia coli / Q000187:drug effects; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry*; D010755:Organophosphates / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D010755:Organophosphates; D011091:Polyesters; D012834:Silver; C033616:poly(lactide)
keywords: (bio)degradable polymeric nanoparticles; Escherichia coli; Staphylococcus aureus; functional polymeric nanoparticles; in vitro antimicrobial efficacy; nanoparticle-based antimicrobial delivery system; silver carbene complexes