## 3 Results and Discussion
### Fabrication of PG Masks with Controlled Dimensions for Additive Material Transfer  
Soft lithography is the most employed technique to create micro- and nanoscale patterns on solid substrates. Although providing the best resolution, the method is expensive, time-consuming, and involves sometimes up to tens of successive steps [39]. Alternative solutions for engineering smart biofunctional surfaces reported in literatures are microcontact printing [46], dip-pen nanolithography [40], ink-jet printing [47], and laser-induced forward transfer (LIFT) [48]. Each method presents distinct advantages, while also exhibiting specific limitations. Here we introduce the possibility to fabricate micropatterns on solid substrates by employing the mask imaging technique. We first employed PLAE to microfabricate hollow masks on PG using UV laser pulses. In this case, the main advantage of PLAE relies on the high versatility of laser direct writing of almost any kinds of shapes. A representative example of round micropatterns with 200-\(\upmu\)m diameter, formed in PG by LDW followed by annealing, is presented in Figure 7a,b. The laser-irradiated micropatterns were constructed in volume using a lens with a 35-mm focal length and 40-mW power at an optimum scanning speed of 0.1-mm/s. This speed was precisely determined since, for slightly higher speeds, the programmed circle shape becomes elliptical. Two-layer exposure was employed by focusing the laser at 125 \(\upmu\)m first and then 375 \(\upmu\)m below the surface in a 500-\(\upmu\)m-thick PG sample volume. This exposure can modify entire PG glass substrates along the \(z\)-axis so that the subsequent chemical etching treatment can create through-holes in the sample (Figure 7c,d). Figure 6: SEM images of square microchambers obtained in PDMS by replication of the PG mold. (**a**) General view of the square microwells of \(150\times 150\)\(\upmu\)m\({}^{2}\) with 60-\(\upmu\)m depth separated by a 50-\(\upmu\)m thickness wall; (**b**) detailed view of (**a**); (**c**) general view of the square microwells of \(50\times 50\)\(\upmu\)m\({}^{2}\) with 30-\(\upmu\)m depth separated by a 50-\(\upmu\)m thickness wall; (**d**) detailed view of (**c**). In the second step, we employed additive MAPLE technique [3; 49] to generate the micropatterns on silicon by transferring the evaporated material through the PG mask (Figure 8). MAPLE is a physical deposition process, typically applied for assembling delicate compounds, both organic and inorganic, on solid substrates. Detailed theoretical and experimental aspects involved in MAPLE are presented elsewhere [50]. Briefly, the procedure is based on laser evaporation of a frozen target, in which the material of interest is dissolved in a solvent. Typically, the ejected molecules are assembled on the substrate to deposit a continuous thin film, while in this case, the structured PG glass was placed in front of the substrate to generate micropatterns. As an additive process, the height of the patterns could be easily controlled by the number of the laser pulses applied for target evaporation. Figure 8: **(a)** Scheme of MAPLE (Matrix-Assisted Pulsed Laser Evaporation) process; **(b)** PG mask with microholes and silicon substrate after transfer of micropatterns; **(c)** SEM image of the transferred GON (Graphene Oxide Nanomaterials) micropatterns on silicon. Figure 7: Fabrication of PG mask with microholes. PG mask after laser exposure and annealing treatment: (**a**) photograph of the sample; (**b**) optical image of central region. PG mask after chemical etching: (**c**) photograph of the sample; (**d**) optical image of central region, PG mask with microholes. In Figure 8b we show photographs of the PG mask after its use in MAPLE transfer of ejected molecules and silicon substrate on which desired patterns of materials are assembled.