Atomic Layer Deposition Modified Track-Etched Conical Nanochannels for Protein Sensing

Abstract

Nanopore-based devices have recently become popular tools to detect biomolecules at the single-molecule level. Unlike the long-chain nucleic acids, protein molecules are still quite challenging to detect, since the protein molecules are much smaller in size and usually travel too fast through the nanopore with poor signal-to-noise ratio of the induced transport signals. In this work, we demonstrate a new type of nanopore device based on atomic layer deposition (ALD) Al2O3 modified track-etched conical nanochannels for protein sensing. These devices show very promising properties of high protein (bovine serum albumin) capture rate with well time-resolved transport signals and excellent signal-to-noise ratio for the transport events. Also, a special mechanism involving transient process of ion redistribution inside the nanochannel is proposed to explain the unusual biphasic waveshapes of the current change induced by the protein transport.

Nanopore Sensing

“…To impart specificity or to eliminate unwanted surface properties from synthetic pores, a wide selection of surface functionalization approaches can be used. For instance, surface properties of nanopore walls can be altered through covalent binding of organosilane molecules, 69 atomic layer deposition (ALD) of alumina, 70–72 or electrostatic adsorption of molecules that have a charge opposite to the nanopore wall surface. 73, 74 Bioinspired nanopore platforms, such as lipid bilayer coated nanopores, 75, 76 biomimetic nuclear pore complexes, 77 and glass pipettes with ion channels trapped at the tip opening 78–80 also have been developed.…”

Chiral Selective Transport of Proteins by Cysteine‐Enantiomer‐Modified Nanopores

“…[14][15][16] Particularly,s olid-state synthetic nanopores have triggered substantial interest in terms of their outstanding mechanical properties and excellent chemical stability. Consequently,t o address this problem, biomimetic strategies have been recently developed and harnessed to explore various biological processes in vitro.I nt his context, artificial biomimetic nanopores provide ac onvenient and robust platform for the study of protein transport.…”

“…Consequently,t o address this problem, biomimetic strategies have been recently developed and harnessed to explore various biological processes in vitro.I nt his context, artificial biomimetic nanopores provide ac onvenient and robust platform for the study of protein transport. [14][15][16] Particularly,s olid-state synthetic nanopores have triggered substantial interest in terms of their outstanding mechanical properties and excellent chemical stability. [17][18][19] By incorporating functional groups onto the nanopores surface,t he artificial system can readily present versatile gate properties and respond to diverse specific environmental stimuli.…”

Universal Scaling of Robust Thermal Hot Spot and Ionic Current Enhancement by Focused Ohmic Heating in a Conic Nanopore

“…Our experiments were done with three kinds of conic nanopores: single polyethylene terephthalate (PET) polymer pores from ion-track irradiation and asymmetric etching [10], silica nanopipettes with a submicron tip radius, and patch pipettes with a 1–3 μ m tip radius (for cellular patch-clamp experiments) from laser-assisted pulling. SEM and conductance measurement at room temperature shows a typical tip radius R t of 5 nm for the polymer conic pores, 100 nm for the silica nanopipettes, and 500 nm for patch pipettes.…”

“…We reduce the surface charge of the silica pipettes with functionalization by N -(3-Triethoxysilylpropyl)gluconamide and validated their low surface charge with ion-current rectification measurements [11]. Fabrication procedures and characterization details are in the Supplemental Material [10,12–14]. …”