title: Biocompatibility and biofouling of MEMS drug delivery devices.
abstract: The biocompatibility and biofouling of the microfabrication materials for a MEMS drug delivery device have been evaluated. The in vivo inflammatory and wound healing response of MEMS drug delivery component materials, metallic gold, silicon nitride, silicon dioxide, silicon, and SU-8(TM) photoresist, were evaluated using the cage implant system. Materials, placed into stainless-steel cages, were implanted subcutaneously in a rodent model. Exudates within the cage were sampled at 4, 7, 14, and 21 days, representative of the stages of the inflammatory response, and leukocyte concentrations (leukocytes/microl) were measured. Overall, the inflammatory responses elicited by these materials were not significantly different than those for the empty cage controls over the duration of the study. The material surface cell density (macrophages or foreign body giant cells, FBGCs), an indicator of in vivo biofouling, was determined by scanning electron microscopy of materials explanted at 4, 7, 14, and 21 days. The adherent cellular density of gold, silicon nitride, silicon dioxide, and SU-8(TM) were comparable and statistically less (p<0.05) than silicon. These analyses identified the MEMS component materials, gold, silicon nitride, silicon dioxide, SU-8(TM), and silicon as biocompatible, with gold, silicon nitride, silicon dioxide, and SU-8(TM) showing reduced biofouling.
authors.affiliation: Department of Biomedical Engineering, Institute of Pathology, Case Western Reserve University, 2085 Adelbert Road, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Voskerician
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Shive
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Shawgo
authors.forename: Horst
authors.initials: H
authors.lastname: von Recum
authors.forename: James M
authors.initials: JM
authors.lastname: Anderson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Cima
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
mesh_terms: D000818:Animals; D001415:Back; D001672:Biocompatible Materials / Q000009:adverse effects*; D002448:Cell Adhesion; D016503:Drug Delivery Systems / Q000009:adverse effects* / Q000295:instrumentation* / Q000379:methods; D004343:Drug Implants / Q000009:adverse effects*; D004581:Electronics; D005122:Exudates and Transudates / Q000276:immunology / Q000378:metabolism; D005260:Female; D005549:Foreign-Body Reaction / Q000175:diagnosis* / Q000209:etiology*; D007958:Leukocyte Count; D008422:Materials Testing / Q000379:methods*; D008904:Miniaturization; D009132:Muscles; D009220:Myositis / Q000175:diagnosis / Q000209:etiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D004343:Drug Implants