Tetrahedral DNA-linked aptamer-antibody-based sandwich-type electrochemical sensor with Ag@Au core-shell nanoparticles as a signal amplifier for highly sensitive detection of α-fetoprotein.

The conventional electrochemical detection strategy for alpha-fetoprotein (AFP) is limited by the antigen-antibody (Ag-Ab) reactions and suffers from low sensitivity and poor reproducibility due to the inconsistency of Ab-modified electrodes. Herein, we designed and explored a sandwich-type electrochemical sensor for highly sensitive detection of AFP based on aptamer (Apt)-AFP-Ab interaction mode with silver@gold (Ag@Au) core-shell nanoparticles (NPs) as a signal amplifier. AuNPs were electrodeposited onto MXene (Ti3C2TX)-modified glassy carbon electrode (GCE) to get AuNPs/MXene/GCE and further used as the signal amplification substrate. The tetrahedral DNA-linked AFP aptamers were immobilized onto AuNPs/MXene/GCE surface via Au-S bonds and used as the sensing and recognition platform for AFP capturing. Ag@AuNPs with core-shell structures were synthesized, characterized, and bound with Ab as detection elements by catalyzing H2O2 reduction. In the presence of AFP, a stable Apt-AFP-Ab sandwich structure was formed owing to the high affinities of aptamer and Ab toward the target AFP. The catalytic current produced by H2O2 reduction increased linearly with the logarithm of AFP concentration from 5 × 10-4 ng/mL to 1 × 105 ng/mL, accompanied by a low detection limit (1.6 × 10-4 ng/mL). Moreover, the novel sandwich-type electrochemical sensor shows high sensitivity, outstanding selectivity, and promising performance in the analysis of actual samples, displaying a broad application prospect in bioanalysis.

Three-dimensional MoS2-graphene aerogel nanocomposites for electrochemical sensing of quercetin.

A facile and novel electrochemical sensing platform is reported for quercetin determination with MoS2 nanoflowers-3D graphene aerogel (3D MoS2-GA) nanocomposite as signal amplified material. The 3D MoS2-GA nanocomposite was synthesized through a two-step hydrothermal method, in which MoS2 nanoflowers were prepared in advance. Characterizations of 3D MoS2-GA were performed by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The 3D MoS2-GA-modified glassy carbon electrode (3D MoS2-GA/GCE) was used to investigate the electrochemical behaviors of quercetin with electrochemical parameters calculated, reaction mechanism discussed, and experimental conditions optimized. Notably, the redox peak current densities of quercetin on 3D MoS2-GA/GCE raised 5.14 and 6.40 times compared with those on a bare GCE. Furthermore, a novel electroanalytical approach was proposed for the sensitive determination of quercetin within the concentration range 0.01 ~ 5.0 µmol/L, accompanied by a low detection limit of 0.0026 µmol/L (at a working potential of 0.38 V vs. Ag/AgCl). The recovery for practical sample analysis ranges from 97.0 to 105%, and the relative standard deviation is less than 4.2%. This established method shows reliable performance in determination of quercetin in tablets and urine samples.

A graphene modified carbon ionic liquid electrode for voltammetric analysis of the sequence of the Staphylococcus aureus nuc gene.

The authors describe a voltammetric method for the detection of the nuc ssDNA sequence originating from Staphylococcus aureus by using a carbon ionic liquid electrode modified with electrodeposited three-dimensional graphene (3DGR). Probe ssDNA was electrostatically adsorbed on the modified electrode by a potentiostatic method. The porous structure and large surface area of 3DGR greatly increase the amount of immobilized probe ssDNA on the interface, which is beneficial for the reaction with target ssDNA. By using Methylene Blue (MB) as the electrochemical probe, the reduction peak current of MB (best measured at -0.30 V vs. SCE) can be used for detecting hybridization. The differential pulse voltammetric current of MB increases linearly in the 1.0 × 10-12 mol L-1 to 1.0 × 10-6 mol L-1 nuc concentration range, and the detection limit is 3.3 × 10-13 mol L-1 (at 3σ). The DNA sensor was successfully applied to the determination of the PCR product of the gene in pork. Graphical abstract Response of an electrochemical DNA biosensor based on the use of a carbon ionic liquid electrode modified with three-dimensional graphene. It enables sensitive voltammetric detection of the specific sequence of the Staphylococcus aureus nuc gene.

Application of Carbon-Microsphere-Modified Electrodes for Electrochemistry of Hemoglobin and Electrocatalytic Sensing of Trichloroacetic Acid.

By using the hydrothermal method, carbon microspheres (CMS) were fabricated and used for electrode modification. The characteristics of CMS were investigated using various techniques. The biocompatible sensing platform was built by immobilizing hemoglobin (Hb) on the micrometer-sized CMS-modified electrode with a layer of chitosan membrane. On the cyclic voltammogram, a couple of quasi-reversible cathodic and anodic peaks appeared, showing that direct electrochemistry of Hb with the working electrode was achieved. The catalytic reduction peak currents of the bioelectrode to trichloroacetic acid was established in the linear range of 2.0~70.0 mmol·L(-1) accompanied by a detection limit of 0.30 mmol·L(-1) (3σ). The modified electrode displayed favorable sensitivity, good reproducibility and stability, which suggests that CMS is promising for fabricating third-generation bioelectrochemical sensors.

Hemin/G-quadruplex and AuNPs-MoS2 based novel dual signal amplification strategy for ultrasensitively sandwich-type electrochemical thrombin aptasensor.

In this work, a novel sandwich-type electrochemical aptasensor based on the dual signal amplification strategy of hemin/G-quadruplex and AuNPs-MoS2 was designed and constructed, which realized the highly sensitive and specific detection of thrombin (TB). In this aptasensor, the 15-mer TB-binding aptamer (TBA-1) modified with thiol group was immobilized on the surface of AuNPs modified glassy carbon electrode (AuNPs/GCE) as capturing elements. Another thiol-modified 29-mer TB-binding aptamer (TBA-2) sequence containing G-quadruplex structure for hemin immobilization was designed. The formed hemin/G-quadruplex/TBA-2 sequence was further combined to the AuNPs decorated flower-like molybdenum disulfide (AuNPs-MoS2) composite surface via Au-S bonds, acting the role of reporter probe. In presence of the target TB, the sandwich-type electrochemical aptamer detection system could be formed properly. With the assistance of the dual signal amplification of AuNPs-MoS2 and hemin/G-quadruplex toward H2O2 reduction, the sandwich-type electrochemical aptasensor was successfully constructed for sensitive detection of TB. The results demonstrate that the fabricated aptasensor displays a wide linear range of 1.0 × 10-6 âˆ¼ 10.0 nM with a low detection limit of 0.34 fM. This proposed aptasensor shows potential application in the detection of TB content in real biological samples with high sensitivity, selectivity, and reliability.

Epithelioid hemangioendothelioma of the retroperitoneal giant type treated with Toripalimab: A case report.

Epithelioid hemangioendotheliomas (EHEs), low-grade malignant tumors of vascular endothelial cell origin, are characterized by vascular endothelial proliferation. In 2002, the World Health Organization classified EHEs as locally aggressive tumors with the potential to metastasize. Currently, the diagnosis of EHE is based on pathology, histological and immunohistochemical examinations. There are no standard treatment guidelines. We here report a 69-year-old man who presented with left-sided chest and abdominal pain for more than 2 months. Enhanced computed tomography of the thorax and abdomen in another hospital suggested a mass in the left adrenal region that was considered malignant. Positron emission tomography- computed tomography in our hospital suggested a large multi-loculated, hypermetabolic, cystic mass in the left adrenal region that was considered malignant. Accordingly, a puncture biopsy of the mass was performed and the diagnosis of EHE confirmed by pathological examination, including immunohistochemical staining. This patient was treated with the programmed death 1 (PD-1) immune checkpoint inhibitor toripalimab with long-term success. The best response was stable disease (SD) with a progression-free survival (PFS) of more than 13 months. The patient is still alive now. Because the sample size of previous studies was small, further studies are needed to determine the safety and efficacy of toripalimab in the treatment of EHE.

The efficacy and safety of chemo-free therapy in epidermal growth factor receptor tyrosine kinase inhibitor-resistant advanced non-small cell lung cancer: A single-arm, phase II study.

OBJECTIVES: The purpose of this study was to explore the efficacy and safety of toripalimab combined with anlotinib in patients with advanced non-small cell lung cancer (NSCLC) who acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). MATERIALS AND METHODS: Patients who developed resistance after using first- or second-generation EGFR-TKIs as their first-line regimen without EGFR T790M mutation or had disease progression after being treated with third-generation EGFR-TKIs as first- or second-line therapy were enrolled. All patients received toripalimab (240 mg/day on Day 1, intravenously) combined with anlotinib (12 mg/day, Days 1-14, orally) once every 3 weeks. Treatment continued until disease progression, or if toxicity was intolerable. The primary endpoint was the objective response rate (ORR) assessed by the investigator. The secondary endpoint was the progression-free survival (PFS). RESULTS: In total, 19 patients were enrolled between May 2020 and October 2021.The ORR was 0%, and a median PFS was 2.1 months (95% CI 0.251-3.949). Grade ≥3 treatment-related adverse events (AEs) occurred in 11% patients. Common adverse events included hypothyroidism (12/19), fatigue (9/19), and hypertension (8/19). Patients in stable disease (SD) group had lower abundance of EGFR mutation allele frequency (AF) before enrollment than those in progressive disease (PD) group (p = 0.031). Patients without detectable EGFR mutation (EGFR-) had longer PFS compared to the ones with EGFR mutations (p = 0.059). Patients with high levels of soluble programmed cell death ligand 1 (PD-L1) at baseline also tended to have longer PFS (p = 0.160). CONCLUSION: Toripalimab combined with anlotinib was tolerable in EGFR-TKI-resistant advanced NSCLC patients not previously treated with chemotherapy. Patients without detectable EGFR mutation and high soluble PD-L1 levels may benefit from this chemotherapy-free treatment.

A Dramatic Response to Toripalimab With Chemotherapy and Antiangiogenic Agent Followed by Surgery in a Stage IIIB Lung Adenocarcinoma Patient With an Uncommon EGFR Mutation: A Case Report.

Lung cancer patients with high programmed cell death-ligand 1 (PD-L1) expression in tumor cells and epidermal growth factor receptor (EGFR) mutations are rare, but there is no clinical standard for which treatment such patients should receive. Here, we report a 52-year-old male smoker who was diagnosed with stage IIIB lung adenocarcinoma. A rare EGFR G719A mutation was detected in the lymph node samples by next-generation sequencing (NGS), and a high PD-L1 expression was found by immunohistochemistry (IHC). After 10 cycles of induction therapy (toripalimab plus pemetrexed plus nedaplatin plus apatinib), surgery was successfully performed, followed by 2 cycles of consolidation therapy (toripalimab plus pemetrexed) and 4 cycles of maintenance therapy (toripalimab). A progression-free survival (PFS) of 7 months was achieved. In this case, we showed that the programmed cell death protein 1 (PD-1) inhibitor toripalimab plus chemotherapy and apatinib was effective and tolerable in a locally advanced EGFR-mutant non-small cell lung cancer (NSCLC) patient with a positive PD-L1 expression.

Large-scale defect-rich iron/nitrogen co-doped graphene-based materials as the excellent bifunctional electrocatalyst for liquid and flexible all-solid-state zinc-air batteries.

Defect-engineering in transition-metal-doped carbon-based catalyst plays an essential role for improving the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance. Herein, we report a ball-milling induced defect assisted with ZnCl2 strategy for fabricating defect-rich iron/nitrogen co-doped graphene-based materials (Fe-N-G). The substantial mechanical shear forces and the constant corrosion to the carbon matrix by ZnCl2 lead to the creation of abundant defects in graphene-based materials, which facilitates doping for heteroatoms. The defect-rich Fe-N-G catalyst with abundant Fe-Nx active sites displays excellent ORR performance. For OER, the over potential for Fe-N-G outperforms that of RuO2 in 1 M KOH at 10 mA cm-2. The Density Functional Theory calculations unravel that the impressive OER performance is attributable to the introduction of abundant defects. Additionally, the liquid and all-solid-state zinc-air batteries equipped with the prepared material as the air cathode demonstrate high power density, high specific capacity, and long charge-discharge stability. This work offers a practical method for manufacturing high-performance electrocatalysts for environmental and energy-related fields.

Poor Prognosis of Pulmonary Adenosquamous Carcinoma with NRAS and HRAS Double Mutation.

RAS mutations constitute one of the major tumorigenic mechanisms and are detected in approximately 20% of lung cancers. The most frequent mutated and well-studied RAS isoform is KRAS, which is associated with an overall poor prognosis in non-small-cell lung cancer (NSCLC). However, the clinical significances of NRAS and HRAS in NSCLC are rarely reported. Here, we present a 58-year-old male smoker who was diagnosed with stage IV lung adenosquamous carcinoma. A rare NRAS and HRAS double mutation was detected in the primary tumor and lymph node samples using next-generation sequencing (NGS). The patient showed rapid disease progression and passed away due to respiratory failure after 15 days of osimertinib in combination with cisplatin. To the best of our knowledge, this is the first report associating NRAS and HRAS double mutation in the poor prognosis of NSCLC.

Voltammetric investigation on interaction of protein with chromotrope 2R and its analytical application.

The electrochemical behaviors of the interaction of chromotrope 2R (CH2R) with human serum albumin (HSA) are investigated on the hanging mercury drop electrode with linear sweep voltammetry. In the acidic buffer solution (pH 2.5) CH2R has a well-defined voltammetric reductive wave at -0.34 V (SCE). On the addition of HSA into the CH2R solution, the reductive peak current of CH2R decreases with little movement of the peak potential. The voltammetric study shows that the electrochemical parameters of interaction solution do not change and a new electrochemically non-active complex is formed via interaction of CH2R with HSA, which cannot be reduced on the Hg electrode and results in the decrease of the free concentration of CH2R. The decrease of reductive peak current is proportional to HSA concentration and further used for protein detection. The binding ratio and the binding constant are further calculated with the experimental voltammetric data.

Highly Exposed Active Sites of Fe/N Co-doped Defect-rich Graphene as an Efficient Electrocatalyst for Oxygen Reduction Reaction.

A defect-rich interconnected hierarchical three-dimensional Fe and N co-doped graphene has been prepared by a facile synthesis with poly (2,5-benzimidazole) (ABPBI) as nitrogen and carbon sources and CaCO3 as the template. ABPBI possesses abundant nitrogen, and pyrolysis of ABPBI is helpful to form graphene structure. CaCO3 and its decomposition products CO2 can promote the formation of interconnected hierarchical porous three-dimensional graphene, which possesses more defects and exposed active sites. Benefiting from the defective catalysis mechanism, rich defect catalysts are applied as electrode materials to enhance the catalytic performance for oxygen reduction reaction (ORR). Electrochemically, the half-wave potential (E1/2 ) of Fe-3D-NG#800 is 0.84 V (vs. RHE), and the accelerated durability tests shows the E1/2 of Fe-3D-NG#800 shifted by a 21 mV drop after cyclic voltammetry scanning for 5000 cycles. Therefore, Fe-3D-NG#800 has excellent activity and durability than 20 wt % Pt/C.

Association between Physical Literacy and Physical Activity: A Multilevel Analysis Study among Chinese Undergraduates.

AIM: To examine the association between the perceived physical literacy (PL) and physical activity (PA) levels among Chinese undergraduates. METHODS: Simplified Chinese version of the Perceived Physical Literacy Instrument and the International Physical Activity Questionnaire were used to measure 536 students' perceived PL and PA levels. Pearson's product-moment correlation and multiple linear regression were then used to examine the relationship between the perceived PL and PA levels. Additionally, standard regression analysis was conducted to test for the effects at different demographics. RESULTS: The correlation between perceived PL and PA level was low but significant (r = 0.350, p < 0.01). The multiple linear regression equation was significant (F = 25.228, p < 0.01, ΔR2 = 0.120). Metabolic equivalent values were used to predict PA levels of participants, which were -3818.582 + 272.535 (motivation) + 249.848 (confidence and physical competence) + 149.899 (interaction with the environment). The association of factors such as socio-economic status (SES) (p = 0.092) and grade point average (GPA) (r = 0.119, p = 0.022) were examined using Pearson's product-moment correlation. Gender (p < 0.01) and body mass index (BMI) (p < 0.01) were also explored for their differences. CONCLUSIONS: Perceived PL and PA levels were significantly related. The association between PL and GPA was identical. GPA and BMI showed significant difference between each group. The study offers a path to explore the concept of PL and how it can affect the PA of Chinese undergraduates. Furthermore, on the basis of this study, more research could develop practical interventions for Chinese undergraduates to enhance their PL and engagement in a lifetime of PA.

Circulating tumor DNA detection is correlated to histologic types in patients with early-stage non-small-cell lung cancer.

OBJECTIVES: Circulating tumor DNA (ctDNA) testing in plasma in patients with non-small-cell lung cancer (NSCLC) has the potential to be a supplemental or surrogate tool for tissue biopsy. Detection of genomic abnormalities in ctDNA and their association with clinical characteristics in early-stage NSCLC need to be clarified. MATERIALS AND METHODS: Here, we comprehensively analyzed gene variations of 48 tumor tissues and 48 matched preoperative (pre-op) plasma and 25 postoperative (post-op) plasma from early-stage NSCLC patients using a targeted 546 genes capture-based next generation sequencing (NGS) assay. RESULTS: In early-stage NSCLC, the average mutation allele frequency (MAF) in pre-op plasma ctDNA was lower than that in tissue DNA (tDNA). The concordant gene variations between pre-op ctDNA and tDNA were difficult to detect. However, we found the tissue- pre-op plasma concordant ctDNA mutation detection ratio in lung squamous cell carcinoma (LUSC) was much higher than that in lung adenocarcinoma (LUAD). We also established a LUSC-LUAD classification model by a least absolute shrinkage and selection operator (LASSO) based approach to help separate LUAD from LUSC based on ctDNA profiling. This model included 14 gene mutations and extracted an accuracy of 89.2% in the training set and 91.5% in the testing set. Correlation analysis showed tDNA-ctDNA concordant ratio was related to histologic subtype, gene mutations and tumor size in early-stage NSCLC. CONCLUSION: This study suggests histology subtype and gene mutations could affect ctDNA detection in early-stage NSCLC. NGS-based ctDNA profile has the potential utility in LUSC-LUAD classification.

Three-dimensional reduced graphene oxide aerogel modified electrode for the sensitive quercetin sensing and its application.

Quercetin belongs to flavonoid drug that has favorable properties such as antiviral, anticancer, anti-allergic and anti-tumor. Therefore a sensitive method is highly required for quercetin determination. In this paper, a three-dimensional reduced graphene oxide aerogel (3D-rGA) with excellent porous framework was synthesized via one-step hydrothermal technique. The characteristics and performances of 3D-rGA were checked by SEM, TEM, BET, XRD, Raman, FT-IR, XPS and electrochemical methods, which exhibited good properties including unique porous structure, large surface area and excellent conductivity. 3D-rGA was further used as the modifier on carbon ionic liquid electrode (CILE) to construct a modified electrode, which was applied to sensitive and selective determination of quercetin. Electrochemical responses of quercetin were accelerated with a pair of symmetrical cyclic voltammetric peaks in good shape appeared and the electrochemical parameters were calculated. The sensitive oxidation response of quercetin from differential pulse voltammetry was verified. Under the selected conditions, electroanalysis of quercetin was established by plotting the oxidation peak currents against quercetin concentrations with linear regression analysis. A wider linear range from 0.1 µmol/L to 100.0 µmol/L was obtained with a detection limit of 0.065 µmol/L (3S0/S). This as-explored approach could be successfully utilized for quercetin detection in Ginkgo tablets.

The Gα1-cAMP signaling pathway controls conidiation, development and secondary metabolism in the taxol-producing fungus Pestalotiopsis microspora.

G-protein-mediated signaling pathways regulate fungal morphogenesis, development and secondary metabolism. In this study, we report a gene, pgα1, that putatively encodes the α-subunit of a group I G protein in Pestalotiopsis microspora NK17, which is known to produce various secondary metabolites, including the antitumor drug taxol and pestalotiollide B (PB). Mutants of pgα1 showed retarded vegetative growth, aging of the mycelium, premature conidiation, deformed conidia, significantly increased melanin production, and a sharp decrease in PB production. The introduction of extra copies of pgα1 led to a different phenotype that was characterized by enhanced production of PB. qRT-PCR revealed that the expression of pks1, which encodes melanin polyketide synthase, an enzyme that is involved in 1, 8-dihydroxynaphthalene (DHN) melanin biosynthesis, was up regulated by 55-fold in the absence of pgα1. Changes in conidiation and PB production in pgα1 mutants were able to be restored by the addition of exogenous cAMP. The deficiencies of PB production and conidiation in Δpgα1 were not able to be rescued by deletion or overexpression of a previously reported histone deacetylase gene (hid1), suggesting that pgα1 is able to override the effect of hid1 on PB production and conidiation. Our results suggested that the G protein-cAMP pathway plays a critical role in vegetative growth as well as in asexual development of P. microspora.

Investigation on direct electrochemical and electrocatalytic behavior of hemoglobin on palladium-graphene modified electrode.

Palladium-graphene (Pd-GR) nanocomposite was acted as modifier for construction of the modified electrode with direct electrochemistry of hemoglobin (Hb) realized. By using Nafion as the immobilization film, Hb was fixed tightly on Pd-GR nanocomposite modified carbon ionic liquid electrode. Electrochemical behaviors of Hb modified electrode were checked by cyclic voltammetry and a pair of redox peaks originated from direct electron transfer of Hb was appeared. The Hb modified electrode had excellent electrocatalytic activity to the reduction of trichloroacetic acid and sodium nitrite in the concentration range from 0.6 to 13.0mmol·L-1 and from 0.04 to 0.5 mmol·L-1. Therefore Pd-GR nanocomposite was proven to be a good candidate for the fabrication of third-generation electrochemical biosensor.

[Fading spectrophotometric determination of heparin with brilliant cresyl blue].

A new fading spectrophotometric method for determining trace heparin is proposed in the present paper. In pH 3.0 Britton-Robinson (B-R) buffer solution, brilliant cresyl blue can react with heparin resulting in the decrease of absorbance of BCB at 592 nm. The conditions for the interaction were optimized, and the interferences of coexisting substances were investigated. Under the optimal conditions the reduction of the absorbance is proportional to the concentration of heparin in the range of 0.6-6.0 mg x L(-1) with the detection limit of 0.173 mg x L(-1). The molar absorptivity of the method was calculated to be 1.03 x 10(6) L x mol(-1) x cm(-1). The method has been applied to determine the heparin sodium injection solution with satisfactory results.

A Putative Histone Deacetylase Modulates the Biosynthesis of Pestalotiollide B and Conidiation in Pestalotiopsis microspora.

Fungi of the genus Pestalotiopsis have drawn attention for their capability to produce an array of bioactive secondary metabolites that have potential for drug development. Here, we report the determination of a polyketide derivative compound, pestalotiollide B, in the culture of the saprophytic fungus Pestalotiopsis microspora NK17. Structural information acquired by analyses with a set of spectroscopic and chromatographic techniques suggests that pestalotiollide B has the same skeleton as the penicillide derivatives, dibenzodioxocinones, which are inhibitors of cholesterol ester transfer protein (CETP), and as purpactins A and C', inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). Strain NK17 can make a fairly high yield of pestalotiollide B (i.e., up to 7.22 mg/l) in a constitutive manner in liquid culture. Moreover, we found that a putative histone deacetylase gene, designated as hid1, played a role in the biosynthesis of pestalotiollide B. In the hid1 null mutant, the yield of pestalotiollide B increased approximately 2-fold to 15.90 mg/l. In contrast, deletion of gene hid1 led to a dramatic decrease of conidia production of the fungus. These results suggest that hid1 is a modulator, concerting secondary metabolism and development such as conidiation in P. microspora. Our work may help with the investigation into the biosynthesis of pestalotiollide B and the development for new CETP and ACAT inhibitors.