Article

In vitro and in vivo characterization of porous poly-L-lactic acid coatings for subcutaneously implanted glucose sensors.

Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.
Journal of Biomedical Materials Research Part A (impact factor: 2.63). 02/2008; 87(3):792-807. DOI:10.1002/jbm.a.31824 pp.792-807
Source: PubMed

ABSTRACT The purpose of this study was to test the hypothesis that porous poly-L-lactic acid (PLLA) sensor coatings reduce fibrosis and promote blood microvessel formation in tissue adjacent to the sensor surface. Porous PLLA coatings were produced using ammonium bicarbonate as the gas foaming/salt leaching agent, and deployed on functional and nonfunctional sensors. The porous coatings minimally affected sensor accuracy and response rate in vitro. Three-week subcutaneous rat studies of nonfunctional glucose sensors showed the anticipated effect of porous coatings enhancing vascularity and decreasing collagen deposition. In contrast, percutaneous functional sensors with and without porous coatings showed no significant difference in terms of histology or sensor response. In spite of the observation that texturing increases the vascularity of the tissue that surrounds implanted sensors, other factors such as the additional mechanical stresses imposed by percutaneous tethering may override the beneficial effects of the porous coatings.

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Keywords

additional mechanical stresses
 
anticipated effect
 
blood microvessel formation
 
decreasing collagen deposition
 
gas foaming/salt leaching agent
 
nonfunctional glucose sensors
 
nonfunctional sensors
 
percutaneous functional sensors
 
percutaneous tethering
 
PLLA
 
porous coatings
 
porous coatings minimally
 
Porous PLLA coatings
 
porous poly-L-lactic acid
 
response rate
 
sensor response
 
sensor surface
 
surrounds implanted sensors
 
texturing increases
 
Three-week subcutaneous rat studies