Protein detection by optical measurement can be obtained through absorption measurements using wavelengths in the range between 270 and 280 nm. Efficient light sources or optical filters in this wavelength range can avoid the use of spectral measurement for detection [1]. A study about the relationship between the reflectivity in the near UV and the vertical aspect ratio was performed for gratings fabricated using low-cost soft lithography which allows for easy replication of wide-area nanopatterns [2]. The reflectivity was measured at 45° in the UV-visible for samples fabricated in silicon and aluminum. A well-defined reflection peak in the range 270 – 280 nm was found in the reflectivity spectrum with features changing depending on the depth of the gratings. Moreover, wetting properties of the gratings were also investigated using contact angle measurements with water droplets, obtaining hydrophobic or hydrophilic gratings depending on the period and depth of the etching.