Printing has fueled the development of a new class of artificial biosystems for the qualitative andquantitative determination of bioanalytes . In particular, the multiscale organization (from nanometersto millimeters) and multiplexed molecular composition (DNA, proteins, lipids, polymers) of such platformsenable the determination of molecular interactions in conditions mimicking/redesigning those of the livingsystems. Since the development of microarrays platforms , the downsizing of the “analyzable” featuredown to femtoliter (fL) scales has permitted to develop new researches in the field of molecularcondensates/confinement. Herein, two relevant examples of fL-scale systems will be discussed,highlighting their applications in bioanalysis. The first one includes molecular inks containing DNAnanoswitches or CYP2E1 catalyzed enzymatic reactions produced by inkjet printing fL-scale compartmentsinto mineral oil drops . The downscaling triggers the organization of a confined environment at thewater/oil interface, resulting in up-concentration effects and molecular crowding. The employ offluorescence lifetime imaging permits to analyze downscaling induced effects, namely up-concentration,heterogeneity and molecular proximity. The second example consists in fL-scale dropletsproduced by microchannel cantilever spotting (μCS) of inks containing single strand DNA (ssDNA) intoporous substrates (nylon), resulting in oligonucleotides microarrays for sensing applications . Thedownscaling to fL-scale imbibition into porous substrates highlights an intriguing and complex processcontrolled by the interplay of spreading, evaporation and capillary effects, being facilitated by glyceroladditive in the ink. The DNA sequences functionality is demonstrated by hybridization with a fluorolabeledcomplementary sequence, producing a double strand sequence (dsDNA). The signal distribution in the spotis homogeneous and allows for the optical detection of spotted oligonucleotides down to few tents ofzeptomoles.
|Title of host publication||AMYC-BIOMED 2020, Autumn Meeting for Young Chemists in Biomedical Sciences|
|Number of pages||1|
|Publication status||Published - 2020|