Surface Of SWCNT Research Articles

Covalent Attachment of Horseradish Peroxidase to Single‐Walled Carbon Nanotubes for Hydrogen Peroxide Detection

AbstractSingle‐walled carbon nanotubes (SWCNTs) are desirable nanoparticles for sensing biological analytes due to their photostability and intrinsic near‐infrared fluorescence. Previous strategies for generating SWCNT nanosensors have leveraged nonspecific adsorption of sensing modalities to the hydrophobic SWCNT surface that often require engineering new molecular recognition elements. An attractive alternate strategy is to leverage pre‐existing molecular recognition of proteins for analyte specificity, yet attaching proteins to SWCNT for nanosensor generation remains challenging. Toward this end, a generalizable platform is introduced to generate protein‐SWCNT‐based optical sensors and use this strategy to synthesize a hydrogen peroxide (H2O2) nanosensor by covalently attaching horseradish peroxidase (HRP) to the SWCNT surface. A concentration‐dependent response is demonstrated to H2O2, confirming the nanosensor can image H2O2 in real‐time, and assess the nanosensor's selectivity for H2O2 against a panel of biologically relevant analytes. Taken together, these results demonstrate successful covalent attachment of enzymes to SWCNTs while preserving both intrinsic SWCNT fluorescence and enzyme function. It is anticipated this platform can be adapted to covalently attach other proteins of interest including other enzymes for sensing or antibodies for targeted imaging and cargo delivery.

Investigation of adsorption properties of SF6 decomposed gases (SO2 and SO2F2) on pristine and Ti-decorated SWCNT surfaces: A DFT study

DFT calculations were employed to investigate the adsorption of gases produced from SF6 decomposition (SO2 and SO2F2) on pristine and Ti- -decorated single-walled carbon nanotubes (Ti-(8,0) SWCNT). All structures were relaxed and their structural and electronic properties were investigated before and after gas adsorption on the surface of the nanotubes. (Ti-(8,0) SWCNT) was found to have high chemisorption sensitivity to Ti, SO2F2 and SO2 adsorptions on its surface. The electronic properties of (8,0) SWCNT were altered from semiconductor to metallic upon decoration with Ti, as demonstrated by the calculated band structures and the density of states (DOS). SO2F2 and SO2 adsorption on the surface of (Ti-(8,0) SWCNT) from different sides transformed the conductor (Ti-(8,0) SWCNT) into a semiconductor nanotube. To more carefully study the nature of adsorption, partial density of states (PDOS) calculations were also made. Additionally, Ti decoration induced a magnetization of approximately 2.61 ?B in (8,0) SWCNT, which disappeared after gas adsorption.

Orientation-Guided Immobilization of Probe DNA on swCNT-FET for Enhancing Sensitivity of EcoRV Detection.

We present a novel approach that integrates electrical measurements with molecular dynamics (MD) simulations to assess the activity of type-II restriction endonucleases, specifically EcoRV. Our approach employs a single-walled carbon nanotube field-effect transistor (swCNT-FET) functionalized with the EcoRV substrate DNA, enabling the detection of enzymatic cleavage events. Notably, we leveraged the methylene blue (MB) tag as an "orientation guide" to immobilize the EcoRV substrate DNA in a specific direction, thereby enhancing the proximity of the DNA cleavage reaction to the swCNT surface and consequently improving the sensitivity in EcoRV detection. We conducted computational modeling to compare the conformations and electrostatic potential (ESP) of MB-tagged DNA with its MB-free counterpart, providing strong support for our electrical measurements. Both conformational and ESP simulations exhibited robust agreement with our experimental data. The inhibitory efficacy of the EcoRV inhibitor aurintricarboxylic acid (ATA) was also evaluated, and the selectivity of the sensing device was examined.

Nitric Oxide Detection Using a Corona Phase Molecular Recognition Site on Chiral Single-Walled Carbon Nanotubes.

Semiconducting single-walled carbon nanotubes (s-SWCNT) are structures that fluoresce in the near-infrared region. By coating SWCNT surfaces with polymeric materials such as single-chain DNA, changes in fluorescence emission occur in the presence of reagents. In this way, polymer-coated SWCNT structures allow them to be used as optical sensors for single molecule detection. Especially today, the inadequacy of the methods used in the detection of cellular molecules makes the early diagnosis of diseases such as cancer difficult at the single-molecule level. In this study, the detection of nitric oxide (NO) signals, which are a marker of cancer, was carried out at the single-molecule level. In this context, a sensor structure was formed by coating the 7,6-chiral s-SWCNT surface with ssDNA with different oligonucleotide lengths (AT). The sensor structure was characterized by using UV-vis spectroscopy and Raman spectroscopy microscopy. After formation of the sensor structure, a selectivity library was created using various molecules. As a result of the coating of the SWCNT (7,6) surface with DNA corona phase formation, Raman peaks at 195 and 276 cm-1 were observed to shift to the right. Additionally, the selectivity library results showed that the (AT)30 sequence can be used in NO detection. As a result of the studies using SWCNT (7.6)- (AT)30, the limit of detection (LOD) and limit of determination (LOQ) values of the sensor against NO were found to be 1.24 and 4.13 μM, respectively.

Evolution of High-Affinity ssDNA Sequence to Carbon Nanotube

Colloidal ssDNA-wrapped single walled carbon nanotube (ssDNA-SWCNT) has been used as the second near-infrared (NIR-II, 1000 -1700 nm) fluorescent nanoprobes with outstanding biocompatibility, and acts as various optical nano sensors for biological analytes such as a dopamine and serotonin. The stability and affinity of ssDNA on the SWCNT surface significantly depends on the sequence of ssDNA, however the large-scale quantitative analysis between ssDNA sequence library, which has high affinity to the SWCNT surface, was repeatedly selected from a random ssDNA(N30) library (~1018) and the resulting sequence data was analyzed. The binding affinity of ssDNA to SWCNT was quantitatively characterized. To quantitatively analyze the kinetics of the process which occurs solvatochromic shift by sodium cholate, assumed the dynamics follow a first-order kinetic model and fit the experimental data using exponential regression, from which decay time constants were determined. As a result, the highest binding affinity of ssDNA to SWCNT was quantitatively characterized by time constant (1.5 X106 sec) which increased by 100 times compared to the N30 random library. Through analysis of the ssDNA sequences with high affinity for the SWCNT surface, we found that the sequences contain high contents of cytosine and adenine nucleotides and complementary base pairs appeared at distance of 5 to 8 bases. This novel sequence library can be applied for the preparation of the ultra-stable ssDNA-SWCNT dispersion and used for anchoring surface ligands for SWCNT as biosensor. Figure 1

Iridium‐Catalyzed Single‐Walled Carbon Nanotube Synthesis by Alcohol‐Gas‐Source Method Under Low Ethanol Pressure: Growth Temperature Dependence

AbstractSingle‐walled carbon nanotubes (SWCNTs) are grown via an Ir‐catalyzed gas‐source‐type cold‐wall chemical vapor deposition (CVD) method under high vacuum. A nozzle injector is used to supply ethanol gas. The grown SWCNT surface shows a colored concentric morphology. This corresponds to the in‐plane distribution of SWCNT lengths, which is induced by in‐plane variations in the ethanol pressure. Raman spectroscopy and scanning electron microscopy are used to investigate the dependence of the SWCNT yield on the growth temperature and ethanol pressure. The ethanol pressure that gives the highest SWCNT yield decreases with decreasing growth temperature. Optimization of the ethanol pressure enables SWCNT growth between 500 °C and 800 °C, and vertically aligned SWCNTs are grown at 700 °C and 800 °C. The SWCNT diameters are small at all growth temperatures, namely less than 0.9 nm for growth at 500 °C and 600 °C, and less than 1.0 nm for growth at 700 °C and 800 °C. The estimated activation energy for SWCNT growth with an Ir catalyst is 0.97 eV, which is much smaller than that with a Co catalyst.

Construction of a cement–rebar nanoarchitecture for a solution‐processed and flexible film of a Bi2Te3/CNT hybrid toward low thermal conductivity and high thermoelectric performance

AbstractSolution processability and flexibility still remain major challenges for many thermoelectric (TE) materials, including bismuth telluride (Bi2Te3), a typical and commercially available TE material. Here, we report a new solution‐processed method to prepare a flexible film of a Bi2Te3/single‐walled carbon nanotube (SWCNT) hybrid, where the dissolved Bi2Te3 ion precursors are mixed with dispersed SWCNTs in solution and recrystallized on the SWCNT surfaces to form a “cement–rebar”‐like architecture. The hybrid film shows an n‐type characteristic, with a stable Seebeck coefficient of −100.00 ± 1.69 μV K−1 in air. Furthermore, an extremely low in‐plane thermal conductivity of ∼0.33 W m−1 K−1 is achieved at 300 K, and the figure of merit (ZT) reaches 0.47 ± 0.02. In addition, the TE performance is independent of mechanical bending. The unique “cement–rebar”‐like architecture is believed to be responsible for the excellent TE performances and the high flexibility. The results provide a new avenue for the fabrication of solution‐processable and flexible TE hybrid films and will speed up the applications of flexible electronics and energy conversion.

Significantly Enhanced Thermoelectric Properties of Copper Phthalocyanine/Single-Walled Carbon Nanotube Hybrids by Iodine Doping.

The copper phthalocyanine/single-walled carbon nanotube (CuPcI/SWCNT) hybrids were fabricated through doping the CuPc/SWCNT mixture using iodine vapor. It was found that both CuPc and SWCNTs were oxidized by iodine vapor resulting in great increase in carrier concentration. Moreover, the strong π-π conjugation interactions between CuPcI- and I-doped SWCNTs make the CuPcI molecules to assemble on the surface of SWCNTs in an ordered face-on packing, which benefits decreasing the carrier transport barrier across the CuPcI/SWCNT interfaces. The combination of iodine bidoping and the ordered face-on packing of CuPcI on the SWCNT surface realizes the synergetic enhancement of carrier concentration and carrier mobility and therefore the great improvement of electrical conductivity. The maximum electrical conductivity (6281 S cm-1) and thermoelectric power factor (∼304 μW m-1 K-2) at room temperature were obtained at a composition of 60 wt % SWCNTs. The power factor value is 3 orders of magnitude higher than the pure CuPcI and 1 order of magnitude higher than SWCNTs. Consequently, the highest ZT value of CuPc/SWCNT hybrids is up to 0.03, which is among the highest value of organic small-molecule complexes.

(Invited) Computational Simulations of Selective Interactions between ssDNA and SWCNTs

Structure-specific interactions between single-stranded DNA oligos and SWCNTs form the basis of important selective sorting methods yet remain poorly understood. Among these interactions is the differential affinity of (ATT)4 for one of the two (7,5) enantiomers. To understand the nature of the affinity difference, we have performed molecular dynamics (MD) simulations followed by free energy (replica exchange) calculations over the temperature range of 290 to 727 K. Comparisons between the conformational free energy landscapes of (ATT)4 structure on right-handed and left-handed (7,5) SWCNTs (respectively known as M and P in stereochemical convention) suggest that (ATT)4 has more contact area with M than with the P enantiomer. However, the corresponding end-to-end distances of (ATT)4 fall nearly in the same region on the landscape. Our standard MD simulations for (ATTT)3 interactions with SWCNTs also suggest that this DNA sequence covers (8,4) SWCNT more effectively than (7,6) and (8,3) SWCNTs, which is consistent with our recent dye-quenching experiments.Other experiments have revealed that when guanines in ssDNA oligos are covalently functionalized to SWCNT sidewalls, the extent of functionalization can depend on the position of the guanine within the oligo. Central positions within long oligos (e.g. T15GT15) lead to greater functionalization than end guanine positions (e.g. T30G). We have performed both standard MD and free energy calculations to investigate the source of this effect. For efficient guanine functionalization of SWCNTs, guanine needs to remain adsorbed on the SWCNT surface. Our computational observations suggest that the central guanine within T15GT15 oligo remains adsorbed on the (6,5) SWCNT surface even when the DNA interacts with other neighboring DNA strands. Under these conditions, the end guanine in T30G is destabilized and tends to desorb from (6,5) SWCNT surface due to inter-strand interactions. Our free energy calculations also suggest that oligos with a central guanine assume more elongated DNA conformations at the surface of a (6,5) SWCNT than do oligos with end guanines. We suggest that DNA elongation is associated with more stable adsorption on the SWCNT surface, supporting efficient covalent functionalization of central guanines. Figure 1

Antioxidant potential of tea assessed by optical absorption spectroscopy in DNA-encased carbon nanotubes

It is essential to develop a simple method to assess food quality quantitatively. Available methods primarily rely on nanotechnology and offer high selectivity and sensitivity. In this study, we aimed to develop a sensitive nanoprobe, and, to this end, a double-stranded DNA-encased HiPco carbon nanotube (dsDNA-HiPco) hybrid was prepared and used to evaluate the antioxidant potential of a Chinese tea against hydrogen peroxide (H2O2) with a range of irradiation wavelengths. The morphology and dispersion of the hybrids were analysed using atomic force microscopy, which showed that dsDNA wrapped on the SWCNT surface well and homogeneous dispersion of the rod-shaped tubes while the concentration of dsDNA was 1 mg mL–1. The antioxidant effect of Chinese tea was evaluated by using near-infrared absorption and photoluminescence of the hybrid. Experimental results revealed that the tea exerted excellent antioxidant effects when the hybrid was pre-treated with 0.03% wt H2O2. Catechin present in the Chinese tea played a pivotal role in exerting the antioxidant effects. Therefore, a simple detection method proposed herein can be successfully applied in various fields, including biology, medicine, and the food industry.

Investigation of Formaldehyde Adsorption on Carbon Nanotubes by Density Functional Theory

Background: Formaldehyde (HCOH) is the most abundant airborne carbonyl indoor volatile organic compound (VOC), which is well-known to cause serious health effects such as respiratory system disease, immune system disorders, and central nervous system damage. Methods: The interaction between HCOH and intrinsic, congeners of Au, Ag, Cu-doped SWCNTs were investigated by density functional theory (DFT) to evaluate the detection of formaldehyde. Results: The results demonstrated that the less adsorption on the surface of intrinsic SWCNT, an HCOH molecule tended to be chemisorbed to the Au, Ag, and Cu atoms of doped SWCNT with larger binding energy of 0.4-0.8 eV and smaller binding distance of 1.9-2.3 Å. Furthermore, charge transfer and density of state studies indicated tha t the electronic properties changed evidently in the most stable HCOH-doped SWCNT systems, mainly at the region of -5.5 to -4.5 eV and Fermi level. Conclusion: More importantly, the adsorption of HCOH affected the electronic conductance of doped SWCNT. It is expected that the results obtained in this study could provide a useful theoretical guidance for the investigation of molecular films interface bonding and design of HCOH sensing devices.

Electrochemical assembly of homogenized poly(3,4-ethylenedioxythiophene methanol)/SWCNT nano-networks and their high performances for supercapacitor electrodes

Homogenized PEDOT/CNT composite is difficult to be fabricated directly from aqueous solution without any solubilizers due to the limitation of insoluble EDOT. Through the introduction of hydroxymethyl group (MeOH) on the EDOT side chain, the designed EDOT-MeOH has very good solubility in aqueous solution. Herein, we firstly used one-step electrochemical co-deposition method to prepare a homogenized PEDOT-MeOH/SWCNT nano-network from the mixed aqueous solution of EDOT-MeOH and SWCNT. SEM and TEM indicated that PEDOT-MeOH uniformly coated on the surface of SWCNT and formed a three-dimensional interpenetrating network. With the increase in the deposited cycles, the thickness of PEDOT-MeOH coating on SWCNT increased regularly. The optimized PEDOT-MeOH/SWCNT nano-network in H2SO4 solution had a specific capacitance of 114.3 mF cm−2 at 5 mV s−1, which was higher than that of PEDOT-MeOH (58.8 mF cm−2), and showed good cycle stability of 80% after 5000 cycles. The enhanced performance mainly comes from the three-dimensional interpenetrating nano-network and the synergistic effect between SWCNT and PEDOT-MeOH. This work realized the facile combination of PEDOT derivatives and SWCNT from pure water solution, which will have good application in electrochemical energy storage devices and in the biosensors and bioelectronics areas due to its good biocompatibility.

Single-Walled Carbon Nanotubes Decorated with Dendrimer-Encapsulated Platinum Nanoparticles as Catalytic Immobilization Matrix for Amperometric Sensing of Glutamate.

Herein, we report the functional decoration of single-walled carbon nanotubes (swCNTs) with Pt dendrimer-encapsulated nanoparticles (Pt DENs) (dia. (1.78 ± 0.18) nm) for the amperometric sensing of glutamate. The functional decoration of swCNTs was carried out via electrochemical grafting of Pt DENs onto swCNTs, and subsequent cross-linking of glutamate oxidase (GluOx) enzymes to the grafted Pt DENs on swCNT surfaces. The critical role of Pt DENs as catalytic immobilization matrix allowed both the immobilization of GluOx enzymes while maintaining the enzymatic activity of GluOx, and the electrocatalytic oxidation of H₂O₂ generated enzymatically in the presence of glutamate. Taking advantage of Pt DENs as catalytic immobilization matrix, the resulting swCNTs films, denoted as GluOx/Pt DEN/swCNTs, were applied as amperometric sensing platforms that display superior analytical characteristics, including sensitivity, selectivity, stability, and reproducibility, to the non-catalytic counterpart (i.e., GluOx/swCNTs), which led to the promising application of GluOx/Pt DEN/swCNTs to the practical analysis of glutamate in real samples.

Surface characterization and London dispersive surface free energy of functionalized single‐walled carbon nanotubes with a blend of polytetrafluoroethylene by inverse gas chromatography

The SWCNTs and SWCNT‐polytetrafluoroethylene (PTFE) blend were prepared by using simple reaction mixture in the presence of chromosorb (SiO2). Surface morphology of SWCNTs and (SWCNT‐PTFE) blend was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and surface BET analysis. In addition, the surface thermodynamic properties of n‐alkanes and polar probe net retention volumes are measured by inverse gas chromatography (IGC). The London dispersive surface free energy values were found to be decreased linearly with increase of temperature. The specific component of the surface free energy of adsorption for the polar probes was obtained using the Donnet‐Park method. The surface character “S” value (Kb/Ka) at SWCNTs was found to be 0.74, and SWCNT‐PTFE blend surface character value was found to be 0.86. This result demonstrates that the (SWCNT‐PTFE) blend surface contains relatively more acidic sites then that of SWCNT surface. Therefore, the IGC results provide useful complementary information on the (SWCNT‐PTFE) blend surface.

Studying physicochemical characteristics of Flutamide adsorption on the Zn doped SWCNT (5,5), using DFT and MO calculations

In this study, the adsorption of Flutamide (FLT) anticancer drug on the Zn doped single-walled carbon nanotube (5, 5) (SWCNT-Zn (5, 5)) has been investigated. This study has been performed in the gaseous phase and in water and ethanol solvents phases, in the basis and excited states, using density functional theory (DFT) and molecular orbitals (MO) calculation methods. DFT calculations performed at B3LYP quantum chemical level abs at 6-311G (d, p) basis set. Firstly, the structure of FLT was optimized at B3LYP/6-311G (d,p) theoretical level. The obtained results clearly demonstrate the energy stability of the optimized geometries and obviously show that the nature of Flutamide adsorption energy on the surface of SWCNT is in the range of the physisorption. Afterwards, the various structures of SWCNT (5, 5) and the adsorption of FLT on the outer surface of SWCNT (5, 5) was investigated using DFT method. The energies of FLT, SWCNT (5, 5), Zn doped SWCNT (5, 5), HOMO and LUMO orbitals, gap energy and dipole moments were calculated using DFT and MO methods.

SWCNT as a Model Nanosensor for Associated Petroleum Gas Molecules: Via DFT/B3LYP Investigations

We investigated the adsorption of associated petroleum gas (APG) molecules: methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), pentane (C5H12), nitrogen (N2), and carbon dioxide (CO2) on the surface of (6, 0) zigzag SWCNT using density functional theory (DFT) calculations to explore a highly sensitive nanosensor for these molecules which take great attention due to environmental and industrial considerations. To better understand the energetic and electronic properties, which include the adsorption energies, HOMO energies, Fermi level energies, LUMO energies, energy gaps, work functions, dipole moments, and the reactivity descriptors are performed for SWCNT in free mode and interacted with the above gas molecules. The molecular electrostatic potential and the electron density surfaces have been constructed. Moreover, we used orbital analysis counting the density of states (DOS) to finding out the possible orbital hybridization between APG molecules and SWCNT. Based on the results, we believe that SWCNT has potential to be a new effective nanosensor for APG molecules.

Characterization of Double-Stranded DNA (dsDNA) on Single-Walled Carbon Nanotubes (SWCNTs)

DNA has been extensively studied due to its versatility as a dispersant of SWCNTs. The specificity and binding affinity of DNA to various analytes has been shown to be strongly sequence dependent. As a result, through modifications of the nucleotide sequence, the DNA conformation on the SWCNT surface can be tailored to suit specific needs for techniques such as single-molecule detection, in vivo imaging, and chirality separation. To date, the majority of research has focused on the interaction between single-stranded DNA and SWCNT surface, with less focus on the nature of the interaction between double-stranded DNA (dsDNA) and SWCNTs. As a result, the exact interaction mechanism governing this type of complex remains strongly debated and largely unknown. In this study, we employ various biochemical methods to infer the conformation of dsDNA on the surface of SWCNTs. Our methods are based on imaging techniques for identifying DNA-modifying enzyme activity in the presence of dsDNA-SWCNT complexes. Our findings suggest that dsDNA can partially retain its native conformation on the SWCNT surface, and the degree of dsDNA accessibility is strongly sequence dependent. These findings offer new possibilities for SWCNT sensing applications that employ dsDNA, such as the optical detection of DNA-protein interactions.

A convenient method of attaching fluorescent dyes on single-walled carbon nanotubes pre-wrapped with DNA molecules

We demonstrated the attachment of different kinds of dyes, Uranine, Rhodamime 800 (R800), and Indocyanine green (ICG), to single-walled carbon nanotubes pre-wrapped with single-stranded DNAs (ssDNA-SWCNTs). A new but simple method was employed, in which a dye solution was added to ssDNA-SWCNTs that had been prepared beforehand in the conventional way. Resulting conjugates of dyes, DNA, and SWCNTs were precisely evaluated by ultraviolet to near-infrared fluorescence/absorbance spectrometry and atomic force microscopy. In particular, simultaneous measurements of fluorescence and absorbance spectroscopy enabled us to find differences in the behaviors of the dyes on SWCNT surfaces. As a result, the fluorescence/absorbance spectra of dyes showed significant changes upon adsorption on SWCNTs. The fluorescence/absorbance peaks of Uranine, R800, and ICG were quenched by 41.3/2.8%, 72.3/48.9%, and 88.3/45.0%, respectively, in the presence of 11.5 μg/mL SWCNTs. We concluded firstly that by pre-wrapping SWCNTs with ssDNA, stable hybrids with these components were obtained even if the dyes used were relatively hydrophobic and secondly that Uranine retained light absorption on the surface of SWCNT while R800 and ICG did not.

Highly enhanced electromechanical properties of PVDF-TrFE/SWCNT nanocomposites using an efficient polymer compatibilizer

PVDF-TrFE/SWCNT nanocomposites with outstanding electromechanical properties were produced using P3HT-PMMA block copolymers as a compatibilizer between PVDF-TrFE and SWCNT. P3HT-PMMA block copolymer coated SWCNT (PTMCNT) was first prepared to utilize π-π stacking interactions between SWCNT and the P3HT block segment. The obtained PTMCNTs are highly compatible with the PVDF-TrFE matrix due to strong hydrogen bonding interaction between the polymer matrix and the PMMA block segment on the surface of SWCNT, leading to a very low percolation behavior at 0.05 wt% of SWCNT in PVDF-TrFE. The obtained electroactive PVDF-TrFE/SWCNT nanocomposites showed ca. 50 times increased electromechanical thickness strain, ca. 3200 times increased elastic energy density, and ca. 460 times increased electrical-to-mechanical energy conversion rate in comparison to those of pristine PVDF-TrFE at the relatively low electric field (50 Vppμm-1). These outstanding properties result from the ultra-low percolation of SWCNT along with uniform local field distribution in PVDF-TrFE, which kept not only intrinsic properties of PVDF-TrFE such as all-trans formed crystalline phase and softness but also enhanced electrical properties including dielectric constant.

A simple and real-time sensing of human serum albumin using antibody-modified CNT-FET

Microalbuminuria is a key indicator for the treatment of cardiovascular or cerebrovascular diseases and death. Therefore, sensitive and specific detection methods of HSA in biological fluids especially in low concentration are necessary in diagnosis and preventive medicine. Here, nanostructured electrical immunosensor is demonstrated for the rapid, sensitive and selective detection of human serum albumin (HSA), using single-walled carbon nanotube (swCNT) field-effect transistor (FETs) functionalized with monoclonal anti-human serum albumin (mAHSA) via simple coating. The selective binding of HSA with mAHSA on the surface of swCNT induces the electrostatic gating effect to the swCNT-FET. The resulting sensor exhibited high sensitivity toward HSA in real time, with good selectivity. The proposed method provides a powerful platform for a real time, sensitive and selective monitoring of HSA in biological fluids.