(DPNs) were synthetized using a top-down fabrication strategy described previously by the authors . Briefly, the process involved the use of a polyvinyl alcohol (PVA) template, as a hydrophilic mold, presenting an ordinate pattern of cylindrical 1,000 x 400 nm wells, which were carefully filled with a polymeric paste. Specifically, DPN were synthetized using a mixture of poly (lactic acid-co-glycolic acid) (PLGA) and poly (ethylene glycol) di-acrylate (PEG-DA) chains. 50 mg of PLGA was dissolved in 1 mL of dichloromethane (CH2Cl2) and mixed with 6 mg of PEG-DA and any other molecule of interest (drug and prodrugs). Then, 0.6 mg of a photo-initiator (2-Hydroxy-4'-(2hydroxyethoxy)-2-methylpropiophenone) was added into the polymeric solution to allow the crosslinking of the PEGDA chains after exposure to UV-light (366 nm). A fixed volume of polymeric mixture including OA-DTXL or PEG-DTXL (5 µL) was then spread through a blade over the PVA template to accurately fill each well. Finally, DPNs were purified via filtration and centrifugation.