Biocompatibility and biofouling of MEMS drug delivery devices

• Published in: Biomaterials Vol. 24; no. 11; pp. 1959 - 1967
• Main Authors: Voskerician, Gabriela, Shive, Matthew S., Shawgo, Rebecca S., Recum, Horst von, Anderson, James M., Cima, Michael J., Langer, Robert
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-05-2003
• Subjects: Animals; Back; Biocompatibility; Biocompatible Materials - adverse effects; Biofouling; Cell Adhesion; Drug Delivery Systems - adverse effects; Drug Delivery Systems - instrumentation; Drug Delivery Systems - methods; Drug Implants - adverse effects; Electronics; Exudate analysis; Exudates and Transudates - immunology; Exudates and Transudates - metabolism; Female; Foreign-Body Reaction - diagnosis; Foreign-Body Reaction - etiology; Leukocyte Count; Material surface analysis; Materials Testing - methods; MEMS component materials; Miniaturization; Muscles; Myositis - diagnosis; Myositis - etiology; Rats; Rats, Sprague-Dawley; Surface Properties; Biocompatibility; Exudate analysis; Material surface analysis; Biofouling; MEMS component materials
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/S0142-9612(02)00565-3

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/μl) 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.