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Celia Morral

Publications and source records attributed to Celia Morral.

2 recordsLinked to original sources

Amino Acid Translocation Through a Dual Nanopore Platform

We demonstrate a dual nanopore platform (DNP) containing a top 2D MoS2 pore in series with a 3 to 5 nm thick SiN pore, vertically separated by 30 nm, with diameters of 1.0 and 3.0 nm, respectively. This platform enables independent probing of analytes by each pore, thereby providing complementary information. We measure translocations of single amino acids (AA) and evaluate current blockades recorded across the two pores upon applying voltage. Small diameters ensured tight passage of individual AAs through the nanopores and provided a good signal-tonoise ratio (RMS current noise of 16 pA_RMS and SNR = 6). We focus on measurements of O-Phospho-L-tyrosine at 400 mV, demonstrating single amino acid detection and a good quantitative agreement with the calculated open pore and blocked currents. Based on these results, future device performance can benefit from slightly smaller pores, specifically the SiN pore, higher voltages and electrolyte concentration, and lower system noise.

physics.app-ph

Reversible nanopore sealing and in situ iron oxide nanoparticle synthesis on thin silicon nitride membranes

We report in-situ synthesis of iron oxide particles inside silicon nitride nanopores via a chemical reaction, monitored by current readout. Nanopores were formed by electroporation on glass chips (diameters from 1.7 to 11.3 nm), transmission electron microscopy (TEM) drilling (diameters from 6.5 to 64.6 nm), or hydrofluoric acid (HF) etching (diameters from 12.6 to 36.2 nm) in 5 to 20 nm thick membranes. Nanopores seal on timescales from ~1 ms to ~3.6 s, across a range of sizes and concentrations. We show single and ~5-pore arrays, as fabricated, after sealing, and after cleaning and pore recovery. These results are independent of fabrication method. Energy dispersive X-ray spectroscopy (EDS), aberration-corrected scanning TEM (AC-STEM), and powder X-ray diffraction (XRD) verify the synthesis of mixed magnetite and maghemite iron oxide. This work advances nanoparticle-nanopore chips for applications in biosensing, plasmonics and photonics when position and size control is required.

cond-mat.mtrl-sci