Patterned and switchable surfaces for biomaterial applications

Chapter 4 – Formation of a chemically patterned substrate for cell microarray applications4.3.4. Cell microarray formationIn order to test the suitability of the polymer microarrays for subsequent formationof a cell microarray, PLLc on a PEG background were incubated with SK-N-SHneuroblastoma cells. This cell line was used as these cells are known to be adherenton many different surfaces, thus, presenting a good model for studying cell adhesiveproperties [228]. Cell array formation was visualised by fluorescence staining withHoechst 33342 after overnight attachment. The resulting fluorescent images areshown in Figure 4.6A and B.Cells were found to adhere well to PLLc as seen by the high numbers of cellsattached to these regions. Typically, 1400 cells were found on each PLLc with adiameter of approximately 400 µm given an average cell area of 90 µm 2 . The cellpattern formed aligns perfectly with the underlying polymer pattern with the resultantcell adhesive areas being well defined (Figure 4.6B). PEG is well known in its abilityto resist cell attachment and protein adsorption [65, 67, 84], whilst, PLL is known topromote the attachment of many different cell types [229]. Thus, this surfacechemistry is universal in nature, being applicable to most adherent cell lines. Thiswas demonstrated by repeating the same experiment using HEK-293 cells, a differentcell line which also formed clear cell patterns matching the underlying polymerpattern (Figure 4.6C). The PEG background showed significantly less cellattachment for both cell lines, enabling the formation of a well defined surfacepattern containing both low fouling and cell adhesive regions. The general approachof a low fouling background coating combined with a photocrosslinked polymer canbe readily adapted to other low fouling background coatings, polymers andcrosslinker chemistries.4-148