| Ion channels exist extensively on cell membranes and undertake physiological activities such as material exchange and signal transmission between cells.The specific external stimulus factors such as light,voltage,gas signal molecules,ions,and biological macromolecules will cause the internal structure of the ion channel to change,prompting the ion channel to open or close,thereby regulating the transmembrane transmission of substances.This act of opening or closing ion channels is called ion gating.The ion-gating behavior in nature has inspired researchers to develop a variety of biomimic nanochannels,and further applied them to the construction of nanofluidic devices and nanosensors,so as to achieve the functions of material detection and separation,control and transmission.Although the ion channels regulated by various external stimuli have been widely studied,the mechanism of their gating behavior is relatively poorly studied.At present,a variety of biosensors have been used for nucleic acid detection,and solid-state nanochannels have been reported in recent years.They can be used to detect biological macromolecules,small molecules,etc.The solid-state nanochannel materials commonly used are mainly 1D,2D nanomaterials,and the three-dimensional nanoscale environment is considered to be conducive to immobilizing more probe molecules,and increasing the contact area between the probe molecules and the target molecules,in order to achieve more transport or detection signals,thereby improving the sensitivity and specificity of the sensor.Nanochannel detection of DNA is mainly based on the principle of DNA hybridization.Single-stranded target nucleic acid is fixed on the surface of the channel.By adding the target single-stranded nucleic acid that hybridizes with it,the surface charge density of the channel or the effective diameter of the channel is changed to trigger a change in current,then achieve the purpose of detecting DNA.Or it can detect oligonucleotides by forming complexes,but this sensing strategy must introduce multiple sensors to build complex DNA nanostructures in the channel.Therefore,it is still a challenge to develop a simple,economical,efficient and label-free nanochannel biosensor for detecting DNA.Therefore,the research is based on the above research background.This article is divided into the following two parts:(1)Based on the work of Chapter 2 of Dr.IMENE BOUSSOUAR’s thesis---"Highly efficient ion-gated nanochannel based on light response of host-guest interaction",further study the effect of adding gold nanoparticles on the gating efficiency,and explore the preparation of Pillar[6]arenes-gold nanoparticle complex with different sizes and its effect on gating efficiency,and its mechanism is studied in detail.This system is based on the isomerization of the photosensitive molecule-azobenzene,which can regulate the reversal of the surface charge of the nanochannel under the irradiation of ultraviolet light and visible light,thereby achieving the transition of the "ON" and "OFF" states of the ion channel.And the system has stability and cyclability,and shows excellent ion rectification characteristics.(2)In order to develop a simple,economical,fast,efficient,and sensitive nanochannel biosensor,we tried to functionalize the nanochannel for the detection of DNA.Because DNA is made up of base pairs connected by phosphodiester bonds,the exposed bare are phosphate anions and the characteristics of functional groups on each base pair.Based on the charge interaction,we designed a Pillar[6]arenes functionalized nanochannels are applied for DNA detection.This system is simple in the construction method,fast in response,and the minimum response concentration is 1 fM.This system displays high gating efficiency(up to 8.63 1),and has the advantages over anti-interference,stability and reversibility.The construction of the functionalized nanochannel provides a new method for detecting DNA and is expected to be used for the detection of target DNA in actual samples. |
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