A hydrogel coating for cochlear implant arrays with encapsulated adipose-derived stem cells allows brain-derived
Philipp Schendzielorz1, Agmal Scherzed, Kristen Rak
1Comprehensive Hearing Center, Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University of Wuerzburg , Germany.
Conclusion:
Human adipose-derived stem cells (ASCs), encapsulated in a fibrin-collagen hydrogel for the coating of an electrode array, produce sufficient amounts of neurotrophic factors and may be suitable for enhancing the bioelectric interface of cochlear implants (CIs).
Objectives:
To evaluate different hydrogel compositions loaded with ASCs with regard to delivery of neuroactive substances and mechanical suitability for the coating of a CI electrode array.
Methods:
ASCs were cultivated in hydrogels consisting of collagen and fibrin in varying fractions (0:1, 1:1, 1:2, and 1:0). The cell proliferation and viability, as well as the production of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and laminin were determined. Two hydrogel compositions were used as a coating for CI electrode arrays and tested in a scala tympani model.
Results:
Cell proliferation was best in collagen/fibrin hydrogel compositions (1:1 and 1:2) and increasing amounts of BDNF (up to 2.59 ng/ml) and laminin (up to 320 ng/ml) were detected. GDNF production was inconsistent and markedly lower. A sufficient coating of a CI electrode carrier in terms of stability and flexibility was achieved only with mixed compositions, although hydrogels formed bulky and uneven layers on the silicone surfaces.
