PC234 Promoting Endothelial Cell Adhesion by Modulation of Prosthetic Surface Topography at the Nano-Scale

Nanotopographic surface engineering can produce a vascular graft surface with the potential to enhance endothelial cell (EC) adhesion. Our aim was to investigate EC response to different nanopit topographies compared to normal, focusing on cell adherence. Two nanopit topographies were studied: the first was a regular symmetric square arrangement (SQ) of diameter 120 nm, center-center spacing of 300 nm, and depth of 100 nm, and the second was a nonsymmetric square surface (NSQ), which provides pits of similar dimensions but with an offset of ±50 nm. The control was smooth topography. Human umbilical vein ECs (HUVECs) were seeded on these substrates and cultured for 5 days. To assess and quantify adherence, In-Cell Western was used to quantify P-myosin and VE-cadherin (cell adhesion proteins). Scanning electron microscopy was used to image the HUVECs and graft surfaces by measuring cell intensity. HUVEC adhesion was present at 5 days on both topographies with a statistically significant upregulation of P-myosin on the NSQ substrate (P < .05) compared with smooth topography. Increased cell counts were found on NSQ, indicating that cell adherence is optimal with this topography (P < .05). Cell intensity measurements were highest with NSQ, showing this topography promotes cell growth. VE-cadherin was upregulated over SQ, and this correlates with a reduced cell count (P < .05). Scanning electron microscopy images show the HUVECs interacting with the different nanopits by way of filopodia. EC adhesion can be increased in vitro by modulating surface topography with nanopits but subtle changes, such as an offset of ±50 nm, can deliver further significant improvement on cell adherence and proliferation. This illustrates the importance of subtle changes in the nanoscale, which can bring around profound changes in cell behavior. Further assessment of the NSQ topography with regards to endothelial cell function is planned. By approximating to normal blood vessel surface, nanotopography, especially nanopits, promises to enhance prosthetic graft function by increasing endothelial adhesion.