Homogeneous Electrochemical Immunoassay Using an Aggregation-Collision Strategy for Alpha-Fetoprotein Detection.

Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity and high efficiency. Homogeneous electrochemical assays, however, are not commonly accessed due to the requirement of electrode immobilization of the recognition elements. Herein, we demonstrate a new homogeneous electrochemical immunoassay based on the aggregation-collision strategy for the quantification of tumor protein biomarker alpha-fetoprotein (AFP). The detection principle relies on the aggregation of AgNPs induced by the molecular biorecognition between AFP and AgNPs-anti-AFP probes, which leads to an increased AgNP size and decreased AgNP concentration, allowing an accurate self-validated dual-mode immunoassay by performing nanoimpact electrochemistry (NIE) of the oxidation of AgNPs. The intrinsic one-by-one analytical capability of NIE as well as the participation of all of the atoms of the AgNPs in signal transduction greatly elevates the detection sensitivity. Accordingly, the current sensor enables a limit of detection (LOD) of 5 pg/mL for AFP analysis with high specificity and efficiency. More importantly, reliable detection of AFP in diluted human sera of hepatocellular carcinoma (HCC) patients is successfully achieved, indicating that the NIE-based homogeneous immunoassay shows great potential in HCC liquid biopsy.

Eu3+-Doped Anionic Zinc-Based Organic Framework Ratio Fluorescence Sensing Platform: Supersensitive Visual Identification of Prescription Drugs.

Advanced techniques for both environmental and biological prescription drug monitoring are of ongoing interest. In this work, a fluorescent sensor based on an Eu3+-doped anionic zinc-based metal-organic framework (Eu3+@Zn-MOF) was constructed for rapid visual analysis of the prescription drug molecule demecycline (DEM), achieving both high sensitivity and selectivity. The ligand 2-amino-[1,1'-biphenyl]-4,4'-dicarboxylic acid (bpdc-NH2) not only provides stable cyan fluorescence (467 nm) for the framework through intramolecular charge transfer of bpdc-NH2 infinitesimal disturbanced by Zn2+ but also chelates Eu3+, resulting in red (617 nm) fluorescence. Through the synergy of photoinduced electron transfer and the antenna effect, a bidirectional response to DEM is achieved, enabling concentration quantification. The Eu3+@Zn-MOF platform exhibits a wide linear range (0.25-2.5 µM) to DEM and a detection limit (LOD) of 10.9 nM. Further, we integrated the DEM sensing platform into a paper-based system and utilized a smartphone for the visual detection of DEM in water samples and milk products, demonstrating the potential for large-scale, low-cost utilization of the technology.

[Clinical Features and Prognosis of Patients with CD5+ Diffuse Large B-Cell Lymphoma].

OBJECTIVE: To analyze the clinical characteristics and prognosis of patients with CD5+ diffuse large B-cell lymphoma (DLBCL). METHODS: The clinical data of 161 newly treated DLBCL patients in Gansu Provincial Hospital from January 2013 to January 2020 were retrospectively analyzed. According to CD5 expression, the patients were divided into CD5+ group and CD5- group. The clinical characteristics and prognosis of the two groups were statistically analyzed. RESULTS: The median age of patients in CD5+ group was 62 years, which was higher than 56 years in CD5- group (P =0.048). The proportion of women in CD5+ group was 62.96%, which was significantly higher than 41.79% in CD5- group (P =0.043). The proportion of patients with IPI score > 2 in CD5+ group was 62.96%, which was higher than 40.30% in CD5- group (P =0.031). Survival analysis showed that the median overall survival and progression-free survival time of patients in CD5+ group were 27(3-77) and 31(3-76) months, respectively, which were both shorter than 30(5-84) and 32.5(4-83) months in CD5- group (P =0.047, P =0.026). Univariate analysis showed that advanced age, positive CD5 expression, triple or double hit at initial diagnosis, high IPI score and no use of rituximab during chemotherapy were risk factors for the prognosis of DLBCL patients. Further Cox multivariate regression analysis showed that these factors were also independent risk factors except for advanced age. CONCLUSION: CD5+ DLBCL patients have a worse prognosis than CD5- DLBCL patients. Such patients are more common in females, with advanced age and high IPI score, which is a special subtype of DLBCL.

Clinically Applicable Homogeneous Assay for Serological Diagnosis of Alpha-Fetoprotein by Impact Electrochemistry.

Tumor protein quantification with high specificity, sensitivity, and efficiency is of great significance to enable early diagnosis and effective treatment. The existing methods for protein analysis usually suffer from high cost, time-consuming operation, and insufficient sensitivity, making them not clinically friendly. In this work, a label-free homogeneous sensor based on the nano-impact electroanalytic (NIE) technique was proposed for the detection of tumor protein marker alpha-fetoprotein (AFP). The detection principle is based on the recovery of current of single PtNP catalyzed hydrazine oxidation due to the release of the pre-adsorbed passivating aptamers on PtNPs from the competition of the stronger binding between the specific interaction of the AFP aptamer and AFP. The intrinsic one-by-one analytical ability of NIE allows highly sensitive detection, which can be further improved by reducing the reaction/incubation volume. Meanwhile, the current sensor avoids a laborious labeling procedure as well as the separation and washing steps due to the in situ characteristic of NIE. Accordingly, the current sensor enables efficient, highly sensitive, and specific AFP analysis. More importantly, the reliable detection of AFP in diluted real sera from hepatocellular carcinoma (HCC) patients is successfully achieved, indicating that the impact electrochemistry-based sensing platform has great potential to be applied in point-of-care devices for HCC liquid biopsy.

Enantioselective oxidation of 1,2-diols with quinine-derived urea organocatalyst.

Quinine-derived urea has been identified as a highly efficient organocatalyst for the enantioselective oxidation of 1,2-diols using bromination reagents as the oxidant. This simple procedure utilizes readily available reagents and operates at ambient temperature to yield a wide range of α-hydroxy ketones in good yield (up to 94%) and excellent enantioselectivity (up to 95% ee).

[Stem sap flow and water consumption of Tamarix ramosissima in hinterland of Taklimakan Desert].

From April to November 2005, the stem sap flow and water consumption of Tamarix ramosissima in the hinterland of Taklimakan Desert was measured by Flow-32 System. The results showed that, in the extremely arid hinterland of Taklimakan Desert and under enough water supply, the average daily water consumption of T. ramosissima with a stem diameter of 3.5 cm and 2.0 cm was 6.322 kg and 1.179 kg, respectively in one growth season. The stem sap flow of T. ramosissima presented a single-peaked curve, with an obvious day and night variation rhythm and fluctuated with environment factors. Under enough water supply, the environmenal factors such as total radiation, wind speed and air temperature were the main factors affecting the stem sap flow, and the dynamics of stem sap flow could be predicted by the liner regression model based on total radiation and wind speed. Because of the extremely arid environment and enough water supply, T. ramosissima had a relatively higher stem sap flow rate and a great water consumption.