Soft tissue reactions evoked by implanted gallium phosphide.
Neural devices may play an important role in the diagnosis and therapy of several clinical conditions, such as stroke, trauma or neurodegenerative disorders, by facilitating motor and pain control. Such interfaces, chronically implanted in the CNS, need to be biocompatible and have the ability to stimulate and record nerve signals. However, neural devices of today are not fully optimized. Nanostructured surfaces may improve electrical properties and lower evoked tissue responses. Vertical gallium phosphide (GaP) nanowires epitaxially grown from a GaP surface is one way of creating nanostructured electrodes. Thus, we chose to study the soft tissue reactions evoked by GaP surfaces. GaP and the control material titanium (Ti) were implanted in the rat abdominal wall for evaluation of tissue reactions after 1, 6, or 12 weeks. The foreign-body response was evaluated by measuring the reactive capsule thickness and by quantification of ED1-positive macrophages and total cells in the capsule. Furthermore, the concentration of Ga was measured in blood, brain, liver and kidneys. Statistically significant differences were noticed between GaP and Ti at 12 weeks for total and ED1-positive cell densities in the capsule. The chemical analysis showed that the concentration of Ga in brain, liver and kidneys increased during 12 weeks of implantation, indicating loss of Ga from the implant. Taken together, our results show that the biocompatible properties of GaP are worse than those of the well-documented biomaterial Ti.
Linsmeier
Cecilia E
CE
Neuronano Research Center, BMC F10, Lund University, SE-221 84 Lund, Sweden. cecilia.eriksson_linsmeier@med.lu.se
Wallman
Lars
L
Faxius
Linda
L
Schouenborg
Jens
J
Bjursten
Lars M
LM
Danielsen
Nils
N
D034861:Abdominal Wall / Q000601:surgery; D000818:Animals; D001672:Biocompatible Materials; D005549:Foreign-Body Reaction; D005708:Gallium; D020007:Implants, Experimental; D008297:Male; D010720:Phosphines; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D014025:Titanium
D001672:Biocompatible Materials; D010720:Phosphines; C485338:gallium phosphide; D005708:Gallium; D014025:Titanium