Screening for compounds released from deep brain stimulation probes by contact with a brain simulant

Area of Science:

• Biomaterials Science
• Neuroscience
• Analytical Chemistry

Background:

• Deep brain stimulation (DBS) is crucial for neurological conditions, utilizing implantable leads.
• Biocompatibility testing is mandatory for regulatory approval of DBS devices.
• Leachables from DBS probes remain unidentified, posing potential safety concerns.

Purpose of the Study:

• To investigate extractables and leachables from polyurethane (PU)-insulated DBS probes.
• To assess the safety profile of polyether urethane (PEU) and polycarbonate urethane (PCU) in a simulated physiological environment.
• To quantify the migration of chemicals from DBS probe materials.

Main Methods:

• Two PU types (PEU, PCU) were incubated with a brain phantom for 180 days at 37°C.
• Extraction with acetone and n-hexane was performed to identify extractables and estimate leachables.
• Analyses utilized gas/liquid chromatography-mass spectrometry and inductively coupled plasma.
• Surface characterization was conducted before and after incubation.

Main Results:

• Concentrations of 4,4'-diphenylmethane diisocyanate decreased by 81.6% (PEU) and 62.3% (PCU).
• Aluminum was detected in PEU (acetone extract) and decreased by 43.1% after incubation.
• Differences in leachable migration between PEU and PCU were observed and correlated with surface changes.

Conclusions:

• The study identified and quantified specific chemical changes in PU-insulated DBS probes.
• Findings indicate a need for evaluating leachable migration in patients undergoing DBS.
• Understanding leachable profiles is critical for ensuring the long-term safety of DBS devices.