Repeated AFM micropipette usage for antibody spotting.

(a) Bright-field image of a spotted droplet of AlexaFluor647-labeled antibody IgG (10 μg/mL) and (b) the corresponding fluorescence image with an intensity profile plot; scale bar = 50 μm; λex = 640 nm ± 15 nm, λem = 700 nm ± 37.5 nm. (c,d) Bright-field image and corresponding fluorescence image of the same spot as shown in (a,b, pos. 1), as well as the subsequently spotted glycerol-water droplet after the cleaning procedure (pos. 2); time period between the delivery of droplets 1 and 2 about 65 min. (e,f) Bright-field image and corresponding fluorescence image with an intensity plot of a spotted antibody droplet (pos. 3) due to repeated frontloading of the same micropipette after several hours of storage. (g,h) Corresponding images with an additional spotted glycerol-water droplet (pos. 4) after a repeated cleaning procedure; time period between the delivery of droplets 3 and 4 about 43 min.