500um quartz wafer with nominal 200nm deep aluminum lines – these are aligned with the flat at left and have width of 38um and pitch of 40um with 2um gap

Yellow blobs are not of interest – these are test areas

coverslipArea of final dna crystal application

red+black sharpie marks indicate center of location of area of interest

These are dna crystals from the center of wafer – this is the region of interest

Grating was pre-warmed to 37 deg. C. 100uL of 200uM pre-cursor dna (5’-GGA CAG ATG GGA-3’) in buffer solution was applied near center of grating. (dna+buffer was pre-heated to 37 deg C for 2 hours). Grating was allowed to rest at room temperature in a sealed chamber with buffer solution in bottom of chamber to provide humid atmosphere for growth. About 16 hours later, the drop was wicked away and a glass coverslip was placed over site of crystal growth.

buffer composition: 120mM magnesium formate dihydrate, 50mM LiCl and 10% w/w 2-methyl-2-4-pentadiol

line analysis of afm scan of Al grating as recieved from WSU, groove depth measures about 160nm

area exposed overnight to growth buffer only

area exposed overnight to 200uM dna in growth buffer - blue arrows indicate some of the visible crystals

transmitted light images of grating with (right) and without (left) dna treatment

top lit optical images of grating with (bottom) and without (top) dna treatment -image at top was treated with buffer only, no dna

-the crystals in the bottom image appear to grow largely from the grooves in the grating

line analysis of afm scan of Al grating as measured outside dna application area, groove depth measured along line as shown

depths measured 165nm and 166nm

depths measured 102nm and 128nm

line analysis of afm scan of Al grating as measured inside dna application area, groove depth measured along line as shown-the difference in groove depth is likely due to dna crystal accumulation in bottom of grooves - also visible are apparent crystals growing from sides of the groove