John Garner

PLGA from PolySciTech used in development of imaging technique for analysis of antibacterial coatings on orthopeadic implants.

Blog Post created by John Garner on Mar 4, 2019

Miller 2019 orthopedic antibiotic PLGA polyscitech.jpg

Whenever an implant is surgically placed, there is always the potential for a bacterial infection to occur leading to an orthopedic implant-associated infection. One means to prevent this is to apply a biodegradable polymer coating which releases antibiotics from the implant to prevent the growth of bacteria in the area surrounding the implant. Recently, Researchers at Johns Hopkins University used PLGA (AP082, AP059) from PolySciTech ( to provide for a model antibiotic-releasing implant coating to test an In vivo bioluminescence imaging technique for determining bacterial growth against. This research holds promise for improved development of bacterial-resistant implants to reduce the incidence of infection post-surgery. Read more: Miller, Robert J., John M. Thompson, Jesse Zheng, Mark C. Marchitto, Nathan K. Archer, Bret L. Pinsker, Roger V. Ortines et al. "In Vivo Bioluminescence Imaging in a Rabbit Model of Orthopaedic Implant-Associated Infection to Monitor Efficacy of an Antibiotic-Releasing Coating." JBJS 101, no. 4 (2019): e12. vo_Bioluminescence_Imaging_in_a_Rabbit_Model.9.aspx


“Background: In vivo bioluminescence imaging (BLI) provides noninvasive monitoring of bacterial burden in animal models of orthopaedic implant-associated infection (OIAI). However, technical limitations have limited its use to mouse and rat models of OIAI. The goal of this study was to develop a larger, rabbit model of OIAI using in vivo BLI to evaluate the efficacy of an antibiotic-releasing implant coating. Methods: A nanofiber coating loaded with or without linezolid-rifampin was electrospun onto a surgical-grade locking peg. To model OIAI in rabbits, a medial parapatellar arthrotomy was performed to ream the femoral canal, and a bright bioluminescent methicillin-resistant Staphylococcus aureus (MRSA) strain was inoculated into the canal, followed by retrograde insertion of the coated implant flush with the articular surface. In vivo BLI signals were confirmed by ex vivo colony-forming units (CFUs) from tissue, bone, and implant specimens. Results: In this rabbit model of OIAI (n = 6 rabbits per group), implants coated without antibiotics were associated with significantly increased knee width and in vivo BLI signals compared with implants coated with linezolid-rifampin (p < 0.001 and p < 0.05, respectively). On day 7, the implants without antibiotics were associated with significantly increased CFUs from tissue (mean [and standard error of the mean], 1.4 × 108 ± 2.1 × 107 CFUs; p < 0.001), bone (6.9 × 106 ± 3.1 × 106 CFUs; p < 0.05), and implant (5.1 × 105 ± 2.2 × 105 CFUs; p < 0.05) specimens compared with implants with linezolid-rifampin, which demonstrated no detectable CFUs from any source. Conclusions: By combining a bright bioluminescent MRSA strain with modified techniques, in vivo BLI in a rabbit model of OIAI demonstrated the efficacy of an antibiotic-releasing coating. Clinical Relevance: The new capability of in vivo BLI for noninvasive monitoring of bacterial burden in larger-animal models of OIAI may have important preclinical relevance.”


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