title: Modulation of the foreign body reaction for implants in the subcutaneous space: microdialysis probes as localized drug delivery/sampling devices.
abstract: 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.
authors: Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA.
authors: Xiaodun
authors: X
authors: Mou
authors: Michelle R
authors: MR
authors: Lennartz
authors: Daniel J
authors: DJ
authors: Loegering
authors: Julie A
authors: JA
authors: Stenken
mesh_terms: D000818:Animals; D000983:Antipyrine / Q000032:analysis; D015190:Blood Glucose Self-Monitoring / Q000379:methods*; D002138:Calibration; D018932:Chemokine CCL2 / Q000627:therapeutic use; D003847:Deoxyglucose / Q000032:analysis; D003907:Dexamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives; D016503:Drug Delivery Systems / Q000379:methods*; D005549:Foreign-Body Reaction / Q000517:prevention & control / Q000628:therapy*; D008297:Male; D017551:Microdialysis / Q000295:instrumentation*; D015233:Models, Statistical; D051381:Rats; D017207:Rats, Sprague-Dawley; D014805:Vitamin B 12 / Q000032:analysis; D015262:Xenobiotics / Q000494:pharmacology
chemical_list: D018932:Chemokine CCL2; D015262:Xenobiotics; C004180:dexamethasone 21-phosphate; D003907:Dexamethasone; D003847:Deoxyglucose; D014805:Vitamin B 12; D000983:Antipyrine