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Thomas Baltz, Christine Haselier, Stephan Hesse, Frank Meißner, Ingolf Endler, Peter Walter, Gabriele Thumann; Effect of Multi-walled Carbon Nanotubes on R28 retinal precursor Cell Survival. Invest. Ophthalmol. Vis. Sci. 2012;53(14):336.
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© ARVO (1962-2015); The Authors (2016-present)
Interfacing neuronal tissue with extracellular electrodes is a promising approach to regain functionality in patients suffering from neuronal degeneration. For retinal degenerative diseases in which photoreceptors are degenerated, e.g. retinitis pigmentosa, prostheses are being developed to restore vision by electrically stimulating surviving retinal cells. Nano modification of microelectrodes represents a valuable approach to optimize electrode properties, such as charge transfer capacity and signal to noise ratio. Aligned multiwalled carbon nanotubes (MWCNT) are an excellent candidate for interfacing them with neural systems. To assess whether MWCNT are applicable for retinal implants, in a first step MWCNT were synthesized on silicon wafers and the survival of R28 retinal precursor cells grown on these wafers was investigated.
Aligned MWCNT were synthesized on 4-inch silicon wafers by chemical vapour deposition. Substrates were deposited with a SiO2 buffer layer followed by an Al2O3 layer to improve CNT length and homogeneity. Iron particles, 3 nm in diameter, were deposited to act as catalyst for aligned CNT growth. The CNT synthesis was carried out at atmospheric pressure using Ar as carrier gas. R28 cells were seeded on silicon wafer pieces with and without MWCNT, as well as on plastic culture dishes. Cell survival was determined using Fluorescein-Diacetat / Propidiumiodid life-dead-assay.
MWCNT exhibited a length of 14.8 µm and average inner and outer diameters of 5 and 10 nm, respectively. R28 cells proliferate and form confluent monolayers on wafers with and without MWCNT. Compared with uncoated wafers, however, cell death of R28 cells grown on MWCNT coated wafers was slightly increased, on average by an amount of 5.69% (p<0.05). The surviving rates were on average 98.50±0.84%, 97.67±0.4231 and 91.99±1.61% (mean±s.e.m.) for R28 cells grown on plastic dishes, uncoated and MWCNT coated wafers, respectively.
Our current data provide evidence that R28 retinal precursor cells are a sensitive indicator to examine putative toxic effects of biomaterials aimed to contact retinal tissue. MWCNT show a small but significant toxic effect on the survival of R28 cells. Optimization of synthesis parameters of MWCNT should further enhance biocompatibility.
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