Inner Wall and Outer Surface Distinguished Solid-State Nanopores for Sensing

Abstract

Solid-state nanopores, inspired by biological nanopores, have the advantages of good mechanical properties, stability, and easy modification. They have attracted wide attention in the fields of sequencing, sensing, molecular sieving, nanofluidic devices, nanoelectrochemistry, and energy conversion. Because of the ion/molecule transport characteristic of the pore, the research on solid-state nanopores mainly focuses on the functional modification of its inner wall. In recent years, the outer surface of nanopores has also attracted the attention of researchers, and the functional elements on the outer surface have the functions of anti-interference and ionic signal enhancement. In this perspective, we review research progress of inner wall and outer surface distinguished solid-state nanopores, highlight their processing and advantages, summarize their functions and applications in sensing, and give insight into further research.

Regulating Nonlinear Ion Transport through a Solid-State Pore by Partial Surface Coatings

“…Another example is the osmotic power generators, where it is known that the surface charge densities at both the inner and the outer surface of a nanopore membrane are important for attaining high energy conversion efficiency . To this end, the partial coating method would allow a fine control of the entrance effects to the ion selectivity by the choice of the dielectric layer on the top surface. , …”

“…52 To this end, the partial coating method would allow a fine control of the entrance effects to the ion selectivity by the choice of the dielectric layer on the top surface. 47,53 In the present work, we focus on manufacturing nanopores with oxide coating to gain control of ion transport. Compared with chemical ways of surface modification with soft organic monolayers, physical approaches such as sputtering is a convenient method to coat nanopores with hard dielectric thin films.…”

Stochastic Sensing of Dynamic Interactions and Chemical Reactions with Nanopores/Nanochannels

“…By analyzing the modulation of the ionic current in blocking amplitude, duration, and frequency, this technology has been applied to real-time sensing of DNA, RNA, peptides, proteins, metabolites, and protein–DNA complexes . It has become an important analysis method in the chemical and biological fields. − Especially in single-molecule detection, nanopore sensing technology shows unique advantages, such as being calibration free, with no amplification required, low dosage, readable long sequences, low cost, and high throughput …”

Solid-State Nanopore Sensors with Enhanced Sensitivity through Nucleic Acid Amplification

“…Compared with biological nanopores, solid-state nanopores constructed from artificial materials, including silicon nitride, silicon oxide, graphene, molybdenum disulfide, boron nitride, anodized aluminum oxide, and polymer membranes, have good mechanical strength, excellent chemical stability and thermal stability, can adapt to complex detection environments, and can be reused to save costs . Solid-state nanopores have adjustable shapes and sizes and can be chemically modified on their inner wall or outer surface, making them suitable for detecting various targets . In addition, their stable structure facilitates integration with other detectors or analytical circuits to construct more sensitive sensors for single-molecule detection …”

“…20 Solid-state nanopores have adjustable shapes and sizes and can be chemically modified on their inner wall or outer surface, making them suitable for detecting various targets. 21 In addition, their stable structure facilitates integration with other detectors or analytical circuits to construct more sensitive sensors for single-molecule detection. 22 The principle of nanopore sensing is to monitor the changes in ion flow caused by analytes passing through the pores under a constant applied voltage (Figure 1a).…”