Single Nucleotide Polymorphism Genotyping in Single‐Molecule Electronic Circuits

Abstract

among individual genomes and understanding the relationship between genetic variations and their biological functions on a genomic scale have attracted extensive attention from geneticists in the postgenomic era. [1] Single nucleotide polymorphisms (SNPs) are prevalent and abundant genetic mutations. Because of their involvement in the emergence of numerous inherited diseases, SNPs have been used as genetic markers for mapping disease loci, [2] and studying candidate gene association, [3] revealing fundamental information for clinical diagnosis and drug discovery for related genetic diseases. [4] Therefore, various genotyping techniques have been developed for SNP detection, such as allele-specific real-time polymerase chain reaction (PCR) assays, [5] hybridization methods based on artificial DNA probes (molecular beacons, peptide nucleic acids (PNAs), and locked nucleic acids (LNAs)), [6] enzyme-assisted primer extension or chain ligation reaction genotyping by using DNA polymerase or ligase, [7] and enzyme mismatch cleavages. [8] However, most of these methods require pre-or post-treatments such as complex and costly PCR or rolling circle amplification steps to generate large amounts of sample collection or for signal enhancement, significantly restricting their applications. [9] To establish high-throughout, simple, and accurate genotyping techniques, with the ultimate goal of detecting SNPs at the single-molecule/single-event level, it is necessary to develop next-generation SNP-genotyping technology based on single-molecule analysis, which is promising for reducing the number of PCR amplification steps and lowering costs. [10] Molecular beacons (MBs), [6a,11] which are derived from hairpin-loop-structured oligonucleotides containing a fluorophore and quencher at different ends of the strand, have been widely used for biological detection both in vitro and in vivo, such as polymorphism analysis, clinical diagnosis, genotyping, and allele discrimination. [12] Because of their enhanced specificity and sensitivity, MBs are common and effective DNA probes for SNP genotyping. A single-base mismatch can be easily distinguished by measuring the differences in fluorescence intensity induced by the mismatched site after binding to well-matched and single-base mismatched targets due to the dynamic diversities of MB hybridization with different targets. Comparing the thermal stability of probe targets and investigating an optimized temperature range to maximize signal Establishing low-cost, high-throughput, simple, and accurate single nucleotide polymorphism (SNP) genotyping techniques is beneficial for understanding the intrinsic relationship between individual genetic variations and their biological functions on a genomic scale. Here, a straightforward and reliable single-molecule approach is demonstrated for precise SNP authentication by directly measuring the fluctuations in electrical signals in an electronic circuit, which is fabricated from a high-gain field-effect silicon nanowire decorated with a single...

Ultrasensitive Detection and Binding Mechanism of Cocaine in an Aptamer‐based Single‐molecule Device

“…In summary, we have demonstrated an efficient single‐molecule electrical detection by using an aptamer‐based biosensor with high sensitivity to provide insights on the conformational changes of cocaine aptamer upon recognition and binding. The nanocircuit‐based structure is label‐free, ultrasensitive, time‐ saving, low‐cost and reproducible, which will be promising for drug detection in clinical or forensic diagnostic applications. The ultrafast response of single‐molecule kinetics reveals that the cocaine aptamer undergoes reciprocal conversion of two conformations before binding, and the binding of cocaine changes the tertiary structure to a state with a higher conductance.…”

Precise Control of Interfacial Charge Transport for Building Functional Optoelectronic Devices

“…The reliable Si NW‐FET biosensor platform is suitable for real‐time label‐free detection of influenza viruses, with high selectivity and single‐molecule sensitivity (Figure b–d). It is also capable of real‐time detection of single molecule dynamic events, such as DNA hybridization (Figure e,f), adenosine triphosphatase hydrolysis, and antigen–antibody interactions . These advantages imply that it is a promising platform for exploring the dynamics of stochastic processes in biological systems, to improve accurate molecular and even point‐of‐care clinical diagnosis (Figure f).…”

“…Recently, we and some other groups found that more efficient functional and hybrid devices can be realized by building more complicated ternary interfaces (Figure e) such as semiconductor/recognition receptor/environment interfaces for specific light/chemistry/biosensing (Figure e, left), or a dye/single layer graphene (SLG)/titanium oxide (TiO 2 ) ternary interface, for efficient charge transport and photovoltaic conversion (Figure e, middle and right). The key to this idea is to separate the signal recognition from charge transport, each performing its own functions without interfering with the other.…”

Complete Mapping of DNA‐Protein Interactions at the Single‐Molecule Level

“…[ 13 , 26 , 27 , 28 ] In this work, we utilize a single‐biomolecule electrical detection platform based on high‐gain SiNW FETs to realize label‐free detection ( Figure 1 a and Figure S1 , Supporting Information). [ 29 , 30 , 31 ] WRKY family proteins as important transcriptional factors in plants play an important role for signal response, stress control and disease resistance. Remarkably, we monitored every detail of the whole binding process of the W‐box DNA and the WRKY1N protein, the N‐terminal WRKY domain of At WRKY1 ( Arabidopsis WRKY1 protein, a member of WRKY family).…”