A combination of (atomic force microscopy)-based fishing (AFM-fishing) and mass spectrometry allows to capture protein molecules from solutions, concentrate and visualize them on an atomically flat surface of the AFM chip and identify by subsequent mass spectrometric analysis. In order to increase the AFM-fishing efficiency we have applied pulsed voltage with the rise time of the front of about 1 ns to the AFM chip. The AFM-chip was made using a conductive material, highly oriented pyrolytic graphite (HOPG). The increased efficiency of AFM-fishing has been demonstrated using detection of cytochrome b5 protein. Selection of the stimulating pulse with a rise time of 1 ns, corresponding to the GHz frequency range, by the effect of intrinsic emission from water observed in this frequency range during water injection into the cell.
Kombinirovannyĭ metod ASM-fishinga i mass-spektrometrii pozvoliaet vylavlivat' belkovye molekuly iz rastvora, kontsentrirovat' i vizualizirovat' ikh na atomarno-rovnoĭ poverkhnosti ASM-chipa, i identifitsirovat' s pomoshch'iu mass-spektrometricheskogo analiza. V rabote predlozhen metod povysheniia éffektivnosti ASM-fishinga za schet prikladyvaniia k ASM-chipu impul'snogo napriazheniia so vremenem narastaniia fronta poriadka odnoĭ nanosekundy (ns). ASM-chip izgotovlen iz provodiashchego materiala – vysokoorientirovannogo piroliticheskogo grafita (VOPG). Povyshenie éffektivnosti ASM-fishinga prodemonstrirovano na primere detektsii belka tsitokhroma b5. Vybor stimuliruiushchego impul'sa s frontom narastaniia odna ns, sootvetstvuiushchim gigagertsovomu diapazonu chastot, byl obuslovlen nabliudaemym nami v étom diapazone chastot éffektom izlucheniia vody pri ee in"ektsii v izmeritel'nuiu iacheĭku.
Keywords: detection of low-copied proteins; protein fishing.