5-hydroxymethylcytosine (5-hmC) is an important epigenetic derivative of cytosine and quantitative detection of 5-hmC could be used as a reliable biomarker for a variety of human diseases. Current technologies used in 5-hmC detection are complicated and time/cost inefficient. In this work, we report the first application of antibody-functionalized carbon nanotube field-effect transistors (CNT-FETs) in quantitative detection of 5-hmC from mouse tissues. This method achieves facile and ultra-sensitive 5-hmC detection based on electrical performance device and avoids complicated processing for DNA samples. The 5-hmC content percentages of normal mouse cerebrum, cerebellum, spleen, lung, liver, and heart samples presented in the genomic DNA were measured as 0.653, 0.573, 0.002, 0.020, 0.076, and 0.009, respectively, which is consistent with previous reports. This technology could be developed into facile routine 5-hmC monitoring devices for clinic human disease diagnoses.
Semiconducting single-walled carbon nanotube (CNT) is a promising candidate as a channel material for advanced logic transistors, attributed to the ultra-thin 1-nm cylindrical geometry, high mobility, and high carrier injection velocity. However, the presence of undesired CNT bundles in the CNT arrays for wafer-scale device fabrication, even when utilizing the state-of-the-art dimension-limited self-alignment (DLSA) method, poses challenges. These CNT bundles degrade the transistor gate's efficiency in controlling the flow of charge carriers in the CNT channel, leading to pronounced device-to-device variability. Here, a novel method is introduced to alleviate bundling in CNT arrays assembled via DLSA, by involving small molecule additive to screen the attractive van der Waals force between neighboring CNTs during the DLSA process, resulting in over 50% reduction in CNT bundling. Furthermore, a pioneering methodology for quantifying CNT bundles is presented and employed experimentally to assess bundles in dense CNT arrays assembled by DLSA using transmission electron microscopy. Both experimental data and molecular dynamics simulation reveal that CNT bundling originates from van der Waals attraction between CNTs, and the disturbed liquid-liquid interface by accumulating excess polar molecules. These findings illuminate new pathways for realizing dense, bundle-free CNT arrays. 相似文献
Transmembrane transport analysis is essential for understanding cell physiological processes. Based on an artificial simulation of internal and external cellular environment, this paper introduces an innovative approach to investigate the microscopic behavior of small molecules through porin protein under mechanical curvature of lipid membrane. A flexible device system is developed, enabling quantitative electronic transmembrane analysis. The key transistor comprises a flexible, microporous electrode covered with the support lipid bilayers (SLBs) to mimic artificial cellular membrane, serving as an extended gate of the field-effect transistor (FET). The transmembrane behaviors of charged ions and small molecules can be effectively monitored in real time by this FET-based flexible device system. The flexibility of the electrode allows analyzing the transmembrane behavior under different mechanical bends. In this study, the developed flexible device is employed for the first time to simulate the mechanical bending of cellular membrane embedded with channel proteins and to monitor the transmembrane behavior of small molecules, thus providing a more authentic representation of membrane protein at a curved state. This approach holds the potential to contribute as a platform-based technological advancement, supporting research into toxicological mechanisms and facilitating drug screening endeavors. 相似文献
Aligned carbon nanotube (A-CNT) with high semiconducting purity and high-density have been considered as one of the most promising active channels for field-effect transistors (FETs), but conjugated polymer dispersant residues on the surface of A-CNT have become the main obstacle for its further development in electronics applications. In this work, a series of removable conjugated polymers (CPs) are designed and synthesized to achieve favorable purification and alignment for CNT arrays with a high density of ≈360 CNTs/µm. Furthermore, a removal process of CPs on the CNT array film is developed. Raman spectra show that the CNTs in array film are almost not damaged after the removal process, and the G/D ratio is as high as 35. The field-effect transistors (FETs) are fabricated with a saturation current density up to 600 µA µm−1 and a current on–off ratio of ≈105, even with a relatively long channel length of ≈3 µm. 相似文献
AbstractThe use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry. The oxidation of Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes (Lac/CNx-MWCNT) and on graphene oxide (Lac/GO) was used to measure the concentrations of catechol and catechin. Nitrogen-doped multiwalled carbon nanotubes (CNx-MWCNT) were synthesized by spray pyrolysis and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Covalently bonded hybrids with laccase (Lac/CNx-MWCNT and Lac/GO) were generated. Catalytic activity of free enzymes determined with syringaldazine yielded 14 584 UmL?1. With Lac/CNx-MWCNT at concentrations of 6.4 mmol L?1 activity was 9326 U mL?1, while enzyme activity measured with Lac/GO at concentration of 6.4 mmol L?1 was 9 234 U mL?1. The Lac/CNx-MWCNT hybrid showed higher stability than Lac/GO at different ethyl alcohol concentrations. The Lac/CNx-MWCNT hybrid can measure concentrations, not previously reported, as low as 1 × 10?8 mol L?1 by measuring the electric current responses. 相似文献
High frequency performance limits of graphene field-effect transistors (FETs) down to a channel length of 20 nm have been
examined by using self-consistent quantum simulations. The results indicate that although Klein band-to-band tunneling is
significant for sub-100 nm graphene FETs, it is possible to achieve a good transconductance and ballistic on-off ratio larger
than 3 even at a channel length of 20 nm. At a channel length of 20 nm, the intrinsic cut-off frequency remains at a few THz
for various gate insulator thickness values, but a thin gate insulator is necessary for a good transconductance and smaller
degradation of cut-off frequency in the presence of parasitic capacitance. The intrinsic cut-off frequency is close to the
LC characteristic frequency set by graphene kinetic inductance (L) and quantum capacitance (C), which is about 100 GHz·μm divided by the gate length.
相似文献
The use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry. The oxidation of Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes (Lac/CNx-MWCNT) and on graphene oxide (Lac/GO) was used to measure the concentrations of catechol and catechin. Nitrogen-doped multiwalled carbon nanotubes (CNx-MWCNT) were synthesized by spray pyrolysis and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Covalently bonded hybrids with laccase (Lac/CNx-MWCNT and Lac/GO) were generated. Catalytic activity of free enzymes determined with syringaldazine yielded 14 584 UmL−1. With Lac/CNx-MWCNT at concentrations of 6.4 mmol L−1 activity was 9326 U mL−1, while enzyme activity measured with Lac/GO at concentration of 6.4 mmol L−1 was 9 234 U mL−1. The Lac/CNx-MWCNT hybrid showed higher stability than Lac/GO at different ethyl alcohol concentrations. The Lac/CNx-MWCNT hybrid can measure concentrations, not previously reported, as low as 1 × 10−8 mol L−1 by measuring the electric current responses. 相似文献
This work presents a simple model for predicting the thermal conductivity of carbon nanotube (CNT) nanofluids. Effects due
to the high thermal conductivity of CNTs and the percolation of heat through it are considered to be the most important reasons
for their anomalously high thermal conductivity enhancement. A new approach is taken for the modeling, the novelty of which
lies in the prediction of the thermal behaviour of oil based as well as water based CNT nanofluids, which are quite different
from each other in thermal characteristics. The model is found to correctly predict the trends observed in experimental data
for different combinations of CNT nanofluids with varying concentrations. 相似文献
Multiwall carbon nanotubes (MWCNTs) were grown by dielectric barrier discharge (DBD)-type plasma enhanced chemical vapor deposition
(PECVD) method in downstream. The temperature was 973 K and the compositions of gases were methane, hydrogen and oxygen in
the total pressure of 0.05 MPa. The effect of O2 concentration in the mixture on the configuration of carbon nanotubes (CNTs) was investigated in detail. Results from scanning
electron microscope (SEM) and transmission electron microscope (TEM) showed that CNTs grown in CH4/H2 (38.6%/61.4%, volume) mixture have many defects and contained disordered graphitic materials. With the addition of appropriate
amount of O2 (∼0.67%), high-purity CNTs could be obtained. However, no CNT, even no carbon matrix existed under the condition of an excessive
oxygen concentration (>1.0%, volume) in the mixture. In order to understand the role of O2 during CNTs growth, optical emission spectroscopy (OES) was in-situ employed and the results predicted that the improvement of CNTs quality in O2 addition was attributed to the effect of OH oxidation from the reaction of atomic oxygen with hydrogen in the plasma. 相似文献
