Purpose:
To investigate the response of trabecular meshwork (TM) endothelial cells to topographically different microstructures and electrospun nanofibers. The topographic effect of the substrates is investigated by quantification of myocilin expression. It is hypothesized that the expression level of myocilin is altered depending on the orientation or scale of the interacting surface of the substrates.
Methods:
Two non-aligned and 2 aligned substrate groups, with one microscale and nanoscale substrate in each group, are investigated relative to a flat surface control. The former consists of 1)microbubble surface and 2)randomly electrospun nanofibers. The latter includes 1)linear microstructures, 2)aligned electrospun nanofibers. A combined micro/nano scale substrate that consists of microstructured electrospun nanofibers is investigated. Poly(etherurethane)urea (PEUU) solution is cured to make a flat surface. A microbubble pattern on the surface is obtained after dissolving KCl crystals on cured flat surfaces. A linear PEUU microstructure is molded by soft lithography. Randomly electrospun fibers are collected on a flat conductive surface by electrospinning. Aligned electrospun fibers are achieved on a rotating collector surface. Microstructured random electrospun fibers are created by using micropatterned electrodes on the collector chip. Three donor eyes are used and western blot is performed three times for each donor. T-tests are performed in SAS with a Bonferroni correction for multiple comparisons.
Results:
Myocilin expression is significantly greater with P≤0.005 in non-aligned group compared to aligned group. Myocilin expression on microstructure PEUU substrate is statistically less than any other single-scale pattern investigated with P≤0.005. Therefore, the orientation effect on myocilin expression is evident in microscale substrates, while the level of myocilin expression is not significantly different based on orientation in nanoscale substrates. In addition, the combined effect of micro and nanoscale of microstructure electrospun fibers is less important compared to individual structure.
Conclusions:
This work shows the topographic parameters of scaffolds can determine cellular characteristics such as the level of protein expression. Topographically random and nanoscale structure are more favorable conditions in TM cell research. Therefore, it will be critical that scaffolds require morphological similarity with natural TM tissue for systematic TM cell study.
Keywords: trabecular meshwork • topography • extracellular matrix