The Sensing Application Of Nanoparticles Based On Solid-state Nanopore

Nanopore is the core component of the fourth-generation gene sequencing technology that promises to achieve rapid detection and costs less than $1,000.It contains bio-nanopore and solid-state nanopore according to the substrate of the nanopore.Bio-nanopore has fixed pore size and good biocompatibility,but its structural stability is greatly influenced by the external environment,the sensitivity of the lipid layer supporting the pore and the pore size vastly limit the condition and range for the detection of the nanopore.In contrast,the advantages of solid-state nanopore are much more pronounced,such as high mechanical strength,stable structure,strong environmental tolerance,controllable aperture and shape,low cost,easy surface and hole marking and modification.In addition to the detection of DNA sequences,solidstate nanopore is also widely used for the detection of biological macromolecules,small molecules,nanoparticles,and metal ions.Microcystin-LR(MC-LR)is a toxic cyanobacterium in natural water,its cyclic stabilizing structure is hardly degraded in water and exists in the ecological circulatory system for a long time.MC-LR has a strong carcinogenic effect on the human body,the content of it in human potable water,prescribed by the World Health Organization,should be less than 1 ?g/L.Most of the methods for detecting MC-LR reported currently are not only time consuming,but also have low sensitivity,it is urgent to explore new methods and techniques for rapid and accurate detection of MC-LR.This subject has proposed a rapid recognition project of MC-LR which is intrinsically different from the detection methods reported before.And it relied on solid-state nanopore detection technology,utilized the advantages of gold nanoparticles(AuNPs)including high surface-to-volume ratio,feasible functionalization with mercapto group,phosphino group,and amino ligand,and unique optical properties.First of all,this study investigated the transport characteristics of two different sizes of AuNPs in nanopore,which obtained different distributions of current blockage generated when different sizes of AuNPs passed through the silicon nitride(Si3N4)nanopore.And it provided the basis for reference of the later detection experiment of MC-LR.After that,the aptamer DNA of MC-LR and its complementary strand DNA(cDNA)were immobilized on AuNPs respectively,and the AuNPs networks obtained through the hybridization of these two complementary strands were uncoupled by the specific interaction of MC-LR and its aptamer.The uncoupled AuNPs networks solution was centrifuged and the AuNPs complexes inside it were detected via nanopore,the proposed Si3N4 nanopore-based AuNPs-aptamer sensor which is capable of specifically recognizing MC-LR was verified on the basis of the current signal generated by the translocation of the AuNPs complexes through the nanopore.