Aquaporin-Inspired CPs/AAO Nanochannels for the Effective Detection of HCHO: Importance of a Hydrophilic/Hydrophobic Janus Device for High-Performance Sensing

Abstract

Probe reactivity has long been considered to play a key role in artificial nanochannel sensors, but systematic studies of membrane wettability on detection performance are currently lacking. Inspired by biological aquaporins, we developed an effective strategy to regulate the hydrophilic/hydrophobic balance by the controllable in situ assembly of coordination polymers (CPs) using BDC-NH 2 on anodic aluminum oxide (AAO) nanochannels to promote HCHO detection. We found that the hydrophobic/hydrophilic balance in CP/AAO heterosomes plays significant roles in the effective detection of HCHO. The hydrophobic AAO barrier layer is necessary to support the confinement effect, while the hydrophilic CP surface is favorable for HCHO to access the channels and then condense with the responsive amine to generate a new imine. The optimized CP/AAO Janus device shows excellent performance in the quantitative analysis of HCHO over a wide range from 100 pM to 1 mM by monitoring the rectified ionic current.

Switchable biomimetic nanochannels for on-demand SO2 detection by light-controlled photochromism

“…Accordingly, asymmetric Janus wettability, i.e., a hydrophilic top surface and a hydrophobic bottom surface, was established on both sides of the SP/AAO nanochannels. As we recently reported 58 , the establishment of Janus wettability not only gated ion transport in the nanochannels but also allowed the nanochannels to achieve an ion rectification effect 59 , 60 . In the right panel of Fig.…”

Biologically Assisted Construction of Advanced Electrode Materials for Electrochemical Energy Storage and Conversion

“…For example, inspired by the amphiphilic characteristics of aquaporin and plasma membranes, which comprise hydrophobic skeleton to stabilize the structure and hydrophilic sites for efficient substance transfer, electrodes with engineered hydrophobicity to ensure robust mechanical stability and high ion migration selectivity were constructed for electrochemical sensors and aqueous batteries. [134][135][136] Janus asymmetric electrodes were also designed with hydrophilic inner surfaces to ensure electrolyte affinity and hydrophobic outer surfaces to avoid electrolyte leakage, resulting in liquidimpermeability and water-floatability. [137] Recently, a more complex design has been proposed by Long, et al with the aim of manipulating oxygen and hydrogen bubbles generated during water electrolysis.…”

“…Ear-of-wheat MWCNTs/Mn 3 O 4 nanocomposite (anode) [139] Bamboo-membrane 2D-2D multilevel graphene/Co 3 O 4 (anode) [241] Honeycomb Bimetallic CoMoO x nanostructures (anode) [243] Nacre shell PPyMADMA binded Si (anode) [104] Spider web Bismuth/CNF (anode) [107] MWCNT/𝛾-Fe 2 O 3 (anode) [108] Pupa-infilled honeycomb Li 2 MnSiO 4 /C (cathode) [244] Spine LiCoO 2 /graphite (full battery) [246] DNA helix LiFeO 4 /graphite (full battery) [247] Lithium-sulfur batteries a) Good LiPSs trapping behavior b) Fast charge/mass transport c) High volume expansion tolerance d) Depressed Li dendrites (for anodes) Dandelion 3D carbon nanotubes coated with S particles (cathode) [257] Ant-nest CNT-nest-S (cathode) [249] Pomegranate LaF 3 doped porous carbon nanofibers (cathode) [258] Hemin enzyme Fe(III) complex grafted on carbon nanotubes (cathode) [259] Intestinal cells ZnO nanowire/C framework (interlayer) [261] Phagocytic cells MWCNTs grafted heptakis(6-amino-6-deoxy)-𝛽-cyclodextrin (interlayer) [262] Mucus layer on fish scales Lithium decylphosphonate layer on Li (anode) [264] Stratum corneum UiO-66-ClO 4 /polydimethylsiloxane layer on Li (anode) [265] Electrocatalysts a) Abundant accessible active sites b) Fast charge/mass transport c) Favorable wettability d) Good durability e) Enzyme mimicking bonding structures Leaf NiCo LDH nanosheets on CuO nanowires (OER) [295] Nanocoral reef Ni(Co,Fe)P nanosheets on WOx nanowire (OER) [296] Mammalian alveoli Au/NiFeOx and Ag/Pt catalyst on pouch-like polyethylene (OER, ORR) [297] Grass carp scales Multiscale structured Pt (Kolbe electrolysis) [126] Subaquatic spiders and diving flies Cu dendrite scaffold (CO 2 reduction) [127] Ultrathin porous Bi 5 O 7 I nanotubes on carbon spheres (NRR) [130] Co 3 O 4 nanosheets on carbon cloth (ORR) [131] Fish scale NiMo alloy and NiFe LDH (HER, OER) [133] Aquaporin and plasma membranes BDC-NH 2 on anodic aluminum oxide (methanal detection) [135] Multiple prototypes (water spider, lotus leave, acati spine)…”

Metal–Organic Framework-Decorated Nanochannel Electrode: Integration of Internal Nanoconfined Space and Outer Surface for Small-Molecule Sensing

“…Moreover, the conventional modification strategy focuses on the signal mediated through the internal portions of nanochannels instead of the function of the outer surface (two ends of a nanochannel). Attempts were made to introduce a specific recognition component (e.g., functional groups and aptamers) into the outer surface of the nanochannels, , which explored the outer surface as an immobilization matrix and provided additional active sites to enrich more targets. However, the potential of the outside portion of nanochannel membranes as a signal generation interface was rarely explored.…”

“…Solid-state nanochannels have been applied in a wide range of fields, including ion/molecular separation, − catalysis, − energy conversion, − and drug delivery, − especially in the sensing field with the increased demand for rapid, sensitive, and real-time detection. − Among recent sensing methods, probing the change of ion current across the axial nanochannels deriving from the presence of analytes has been the dominant signaling strategy. − The Ag/AgCl electrode is the commonly used electrode to collect ion current; however, it usually fails to function in different types of redox reactions, significantly restricting the strategic adaptability. Moreover, the conventional modification strategy focuses on the signal mediated through the internal portions of nanochannels instead of the function of the outer surface (two ends of a nanochannel).…”