In vitro elution of silver nanoparticles from three carrier media

OBJECTIVETo determine and compare the rate, pattern, and completeness of silver nanoparticle (AgNP) elution in vitro over 7 days from 3 carrier media in PBSS. SAMPLEAgNPs in calcium sulfate hemihydrate (CSH) beads, poloxamer 407 gel, and a gelatin sponge. PROCEDURESThree carrier media were used to create constructs containing AgNPs (8,500 ng). All constructs were submerged in PBSS and stored at 38°C for 7 days. Samples were collected after 2, 6, 12, 18, 24, 36, 48, 72, 96, 120, 144, and 168 hours, and AgNP concentration was measured with inductively coupled plasma mass spectrometry. Constructs were tested in quadruplicate. RESULTSSustained release of AgNPs was seen from all constructs for a minimum of 72 hours. Release from all constructs was incomplete, with an initial burst during the first 24 hours followed by a time-dependent decrease in elution rate for up to 168 hours. A mixed-effects model showed a significant difference in AgNP release over time (P < .001) and among media (P < .001). AgNP-gel constructs released the largest quantity of AgNPs (8,401.02 ng [98.84%]), followed by AgNP-sponge constructs (1,503.45 ng [17.69%]). Release from AgNP-CSH bead constructs was 87.824 ng (1.03%), with no additional release after 72 hours. CLINICAL RELEVANCESustained release of AgNPs is possible in vitro, but efficacy against bacterial infections needs to be investigated prior to clinical use.