Modulation of the foreign body reaction for implants in the subcutaneous space: microdialysis probes as localized drug delivery/sampling devices

by Mou, Xiaodun; Lennartz, Michelle R.; Loegering, Daniel J.; Stenken, Julie Ann

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Modulation of the foreign body reaction is considered to be an important step toward creation of implanted sensors with reliable long-term performance. In this work, microdialysis probes were implanted into the subcutaneous space of Sprague-Dawley rats. The probe performance was evaluated by comparing collected endogenous glucose concentrations with internal standard calibration (2-deoxyglucose, antipyrine, and vitamin B12). Probes were tested until failure, which for this work was defined as loss of fluid flow. In order to determine the effect of fibrous capsule formation on probe function, monocyte chemoattractant protein-1/CC chemokine ligand 2 (MCP-1/CCL2) was delivered locally via the probe to increase capsule thickness and dexamethasone 21-phosphate was delivered to reduce capsule thickness. Probes delivering MCP-1 had a capsule that was twice the thickness (500-600 μm) of control probes (200-225 μm) and typically failed 2 days earlier than control probes. Probes delivering dexamethasone 21-phosphate had more fragile capsules and the probes typically failed 2 days later than controls. Unexpectedly, extraction efficiency and collected glucose concentrations exhibited minor differences between groups. This is an interesting result in that the foreign body capsule formation was related to the duration of probe function but did not consistently relate to probe calibration.

Journal
Journal of Diabetes Science and Technology
Volume
5
Issue
3
Year
2011
Start Page
619
ISBN/ISSN
1932-2968
PMID
21722577
DOI
10.1177/193229681100500316