MOF-MWCNT functionalized sponge as a single-adsorbent in Sin-QuEChERS cleanup platform for efficient multi-pesticide analysis in Codonopsis radix.

High-sensitive electrochemical sensor based on Ni/NiCx-integrated functional carbon nanotubes for simultaneous determination of acetaminophen and dopamine

Plant growth regulators (PGRs) enhance the biosynthesis of plant secondary metabolites but can cause environmental pollution and health risks, especially if synthetic or overused. Here, we developed a simple, high-throughput method using salting-out extraction and LC-MS/MS to analyze 62 PGR residues. The extraction, chromatographic conditions, and spectrometric parameters were systematically optimized. The extraction process was performed with acetonitrile-water (1:1), EN15662 extraction salt and d-SPE sorbent. This method was applied to analyze commercial and field trial Codonopsis Radix (CR) samples. The limit of quantification (LOQ), for 62 PGRs ranged from 0.03 to 82.50 μg/kg, and the limit of detection (LOD) ranged from 0.01 to 18.58 μg/kg. Furthermore, we employed plant metabolomics to assess changes in secondary metabolites in CR following fertilizer application and conducted a correlation analysis to explore the relationship between PGRs and secondary metabolites. In commercial samples, residues of 10 PGRs were detected, while in field trial samples, residues of 7 PGRs were found. In plant metabolomics, the arrangement of CR samples, which have been exposed to different fertilization levels, along the axes of partial least squares-discriminant analysis (PLS-DA) indicates that the chemical composition of CR experiences substantial alterations once a particular fertilization threshold is surpassed. The correlation analysis showed that PGRs boost amino acid metabolite synthesis and inhibit alkaloid biosynthesis. This study focuses on quality and safety concerns from the unchecked use of PGRs in CR production. It offers a framework for standardized cultivation and quality control to ensure the sustainable development of Traditional Chinese Medicine.

Fabrication of novel electrochemical immunosensor by mussel-inspired chemistry and surface-initiated PET-ATRP for the simultaneous detection of CEA and AFP

Codonopsis Radix is commonly used as a tonic in traditional Chinese medicine. However, there is no suitable method to assess the quality of Codonopsis Radix based on multiple components having potential bioactivities. To establish a HPLC/UV method for simultaneous quantitation of polyacetylenes (lobetyol, lobetyolin, lobetyolinin, cordifolioidyne B), phenylpropanoid (tangshenoside I) and pyrrolidine alkaloids (codonopyrrolidiums A, B) in Codonopsis Radix. Large-scale methanol extraction of Codonopsis Radix, followed by chromatographic separation, provided the seven analytes for quantitation standards. Ultrasound-assisted methanol extracts of samples were analysed using reversed phase, gradient elution HPLC monitored at 215 nm. The method developed allowed efficient separation of the seven compounds and the detection and quantitation limits of the seven analytes were 0.10-0.32 µg/mL and 0.35-1.07 µg/mL, respectively. All calibration curves showed good linearities (r>0.9993) within the test ranges. Intraday and interday precisions were good with RSD<2.84%. The recoveries of all analytes ranged from 95.8 to 104.7%. HPLC/UV is an efficient and accurate method of analysis for simultaneous quantitation of seven components in Codonopsis Radix.

Effective NADH sensing by electrooxidation on carbon-nanotube-coated platinum electrodes

Unraveling the chemical constituents, absorption characteristics, and metabolic profile of Codonopsis Radix based on UPLC-Q- Orbitrap MS

A cyclodextrin-deep eutectic solvent-based dispersive liquid-liquid microextraction method for quantitative determination of small molecules in fresh-cut Codonopsis Radix.

Simultaneous determination of lobetyolin and atractylenolide III in Codonopsis Radix by dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent

Multiwalled carbon nanotube (MWCNT) films have been fabricated by using plasma-enhanced chemical vapor deposition system onto Cr–Au patterned alumina substrates, provided with 3nm thick Fe growth catalyst, for NO2 and NH3 gas sensing applications, at sensor temperature in the range of 100–250°C. Nanoclusters of noble metal surface catalysts (Au and Pt) have been sputtered on the surface of MWCNTs to enhance the gas sensitivity with respect to unfunctionalized carbon nanotube films. It was found that the gas sensitivity of Pt- and Au-functionalized MWCNT gas sensors significantly improved by a factor up to an order of magnitude through a spillover effect for NH3 and NO2 gas detections, respectively. The metal-functionalized MWCNT sensors exhibit very high gas sensitivity, fast response, reversibility, good repeatability, and sub-ppm range detection limit with the sensing properties of the MWCNT films tailored by surface catalyst used to functionalize the MWCNT sensors.

We designed a hydrogen peroxide biosensor. The electrochemical detection of H2O2 was performed based on immobilization of cobalt nanoparticles–ferritin (CoNPs–Fer) onto multiwalled carbon nanotubes (MWCNTS) ensnared into chitosan (CS) matrices. Electrochemical techniques such as differential pulse voltammetry (DPV) and cyclic voltammetry (CV) was used to check the property of biosensor. Energy-dispersive X-ray spectroscopy (EDXS) and field emission scanning electron microscopy (FESEM) techniques showed the prosperous immobilization of CoNPs–Fer on the modified GC electrode surface. The hydrogen peroxide-designed biosensor displayed a linear range from 0.2 to 14 nM (R2 = 0.99), a detection limit of 1.29 nM (S/N = 3) and sensitivity of –0.1105 μA/nM.The apparent heterogeneous electron transfer rate constant (Ks) and the charge transfer coefficient (α) were gained 4.19 s–1 and 0.49, respectively. This biosensor can detect hydrogen peroxide with high sensitivity, selectivity, and low detection limit.

High-index {hk0} facets platinum concave nanocubes loaded on multiwall carbon nanotubes and graphene oxide nanocomposite for highly sensitive simultaneous detection of dopamine and uric acid

Hollow nanocages heterostructured NiCo-LDH/MWCNTs electrocatalyst for highly sensitive and non-invasive detection of saliva glucose

A seawater temperature sensing and detection method based on microfibre resonator (MR) by intensity-variation scheme is proposed, which has the advantages of high sensitivity and low detection limit. The dependences of sensitivity on probing wavelength, fibre diametre and ring diametre are studied. Results show that probing wavelength influences the sensitivity by the absorption loss predominantly. Larger absorption loss results in lower sensitivity, which is much different with resonant-wavelength-shift scheme. And sensitivity increases with the increasing ring diametre due to the decreasing bending loss and increasing Q-factor. In addition, there may exist an optimal fibre diametre, with which the sensitivity is maximized. By tuning the parameters of system, sensitivity can be tuned from 0.0784 NI/°C to 13.79 NI/°C (NI is the abbreviation of normalized intensity). Correspondingly, dynamic range changes from 11.77°C to 0.08°C. Additionally, the dependences of detection limit on wavelength, fibre diametre, and ring diametre are also investigated, which are opposite to that of sensitivity. For different temperatures, the dependences of sensitivity and detection limit at some typical temperatures are studied, which shows that high sensitivity and low detection limit are related to high temperature, and the optimal fibre diametres for high sensitivity and low detection limit are the same at different temperatures. The lowest detection limit is estimated to be 10-7°C level, which is four orders of magnitude smaller than that of the traditional method. Results shown here are beneficial to find the optimal parameters for the temperature sensors, and offer helpful references for assembling micro-photonics device used in seawater sensing and detection.

In this work, a resistive sensor based on multiwalled carbon nanotube (MWCNT) - poly(diallyldi- methylammonium chloride) solution (PDDA) composite is proposed for highly sensitive carbon monoxide (CO) detection at room temperature. The surface of MWCNTs is functionalized with PDDA, and the functionalization is investigated by Fourier transform infrared and Raman spectroscopy. The MWCNT-PDDA composite is used as a sensing material with deposited interdigitated electrodes (IDE) of silver (Ag) on glass substrates. The resistance of the sensors changes due to charge transfer from CO to the positively charged quaternary ammonium group present on PDDA. The developed sensors are able to detect very low concentrations of CO gas ranging from 1 to 20 ppm with high sensitivity and limit of detection (LOD) of 127 ppb. The interference of other gases and volatile organic compounds is investigated, and the results are presented. The influence of humidity and temperature on the sensors is also explored. The stability and repeatability of the sensors are examined, and the sensors are almost stable for 2 months with excellent reproducibility. The sensors also follow the Langmuir adsorption/desorption model. The sensors have shown excellent potential for rapid CO gas sensing, and it can be used in wearable electronics applications.

Next-Generation Sequencing (NGS) allows high throughput mutation analysis of oncogenes and tumor suppressor genes by targeted resequencing. However, increased sensitivity for mutation detection due to the spatial heterogeneity of the solid tumor or temporal heterogeneity found within the circulating free DNA (cfDNA) may be needed to identify the key biomarkers that may guide the personalized treatment for patients in the era of precision medicine. ICE COLD-PCR (ICP) technology is capable of simultaneous enrichment of mutations targeted by a ∼50 base reference oligonucleotide in a modified PCR reaction followed by standard Sanger sequencing. In this study, we sought to establish a high sensitivity and high throughput mutation detection platform using ICP combined with NGS. ICP products from low frequency mutation mixtures were enzymatically treated, ligated to the Ion Torrent adapters and analyzed by the Ion Torrent Personal Genome Machine (PGM) and the MiSeq NGS platforms. The ICP-NGS analysis of low-level mutations provided a virtual increase in depth of coverage ahead of NGS analysis that increased the sensitivity of NGS detection. High sensitivity detection of cancer genetic biomarkers from cfDNA has the potential to facilitate cancer diagnosis and provide guidance for personalized cancer treatment by serving as a liquid biopsy when there is no available tumor tissue and as a process for monitoring treatment effectiveness and emergence of drug resistance. To explore the clinical utility of the ICP-NGS platform in detecting cancer mutations in cfDNA, 26 plasma DNA samples harvested from patients with carcinomas were analyzed simultaneously with NGS for PIK3CA exons 9 and 20, KRAS exon 2, and EGFR exons 18 and 19 with or without prior ICP enrichment for mutants. For the 15 variants (P&amp;lt;0.01 and freq&amp;gt;5%) detected by ICP-NGS, only 3 variants were observed in NGS without ICP; even so, the mutant frequency for the 3 variants was low (∼5-10%) without the prior ICP enrichment but was enriched to ∼80-90% after the ICP. More importantly, 12 of the 15 variants detected by ICP-NGS were only detectable in NGS analysis because of the prior ICP enrichment. These results support the application of ICP in front of NGS in high-sensitivity and high-throughput detection of mutants in cfDNA. In conclusion, we have established a platform of mutant enrichment by ICE COLD-PCR followed by NGS analysis that is capable of high sensitivity and high throughput detection of cancer genetic biomarkers. ICP-NGS detected the 80% of mutations in cfDNA that were undetectable without ICP enrichment, suggesting that ICP-NGS has the potential to detect and monitor patients' genetic biomarker in real-time and provide guidance for the personalized cancer treatment. Citation Format: Rui Lin, Sarah Cherubin, Courtney Cubrich, Grant Wu, Ben Legendre, Katherine Richardson. Mutant enrichment by ICE COLD-PCR prior to the next-generation sequencing enables high sensitivity and high throughput detection of cancer biomarkers in patient samples. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1506. doi:10.1158/1538-7445.AM2014-1506