Researchers including Mehdi Tajvidi of University of Maine recently reported on the use of cellulose nanocrystals to print on transparent substrates in ACS Applied Materials & Interfaces. The method uses a cellulose nanocrystal/polymer ink that can be directed to self-assemble at the nanoscale to produce 3D micro-figures by using known surface evaporation phenomenon and surface tension forces (known as birefringent printing, a form of photonic printing). The method has many potential applications, including in anti-fraud applications and has several benefits over other photonic printing methods including low cost, low toxicity, high accuracy, and high contrast. Further, the authors report it is almost impossible to forge.