Construction of AlGaN/GaN high-electron-mobility transistor-based biosensor for ultrasensitive detection of SARS-CoV-2 spike proteins and virions.

The COVID-19 pandemic has highlighted the need for rapid and sensitive detection of SARS-CoV-2. Here, we report an ultrasensitive SARS-CoV-2 immunosensor by integration of an AlGaN/GaN high-electron-mobility transistor (HEMT) and anti-SARS-CoV-2 spike protein antibody. The AlGaN/GaN HEMT immunosensor has demonstrated the capability to detect SARS-CoV-2 spike proteins at an impressively low concentration of 10-22 M. The sensor was also applied to pseudoviruses and SARS-CoV-2 ΔN virions that display the Spike proteins with a single virion particle sensitivity. These features validate the potential of AlGaN/GaN HEMT biosensors for point of care tests targeting SARS-CoV-2. This research not only provides the first HEMT biosensing platform for ultrasensitive and label-free detection of SARS-CoV-2.

Identification and evaluation of circulating exosomal miRNAs for the diagnosis of postmenopausal osteoporosis.

BACKGROUND: Postmenopausal osteoporosis (PMOP) is a common condition that leads to a loss of bone density and an increased risk of fractures in women. Recent evidence suggests that exosomal miRNAs are involved in regulating bone development and osteogenesis. However, exosomal miRNAs as biomarkers for PMOP diagnosis have not been systematically evaluated. In this study, we aim to identify PMOP-associated circulating exosomal miRNAs and evaluate their diagnostic performance. METHODS: We performed next-generation sequencing and bioinformatics analysis of plasma exosomal miRNAs from 12 PMOP patients and 12 non-osteoporosis controls to identify PMOP-associated exosomal miRNAs, and then validated them in an independent natural community cohort with 26 PMOP patients and 21 non-osteoporosis controls. Exosomes were isolated with the size exclusion chromatography method from the plasma of elder postmenopausal women. The plasma exosomal miRNA profiles were characterized in PMOP paired with controls with next-generation sequencing. Potential plasma exosomal miRNAs were validated by qRT-PCR in the validation cohort, and their performance in diagnosing PMOP was systematically evaluated with the receiver operating characteristic curve. RESULTS: Twenty-seven miRNAs were identified as differentially expressed in PMOP versus controls in sequencing data, of which six exosomal miRNAs (miR-196-5p, miR-224-5p, miR320d, miR-34a-5p, miR-9-5p, and miR-98-5p) were confirmed to be differentially expressed in PMOP patients by qRT-PCR in the validation cohort. The three miRNAs combination (miR-34a-5p + miR-9-5p + miR-98-5p) demonstrated the best diagnostic performance, with an AUC = 0.734. In addition, the number of pregnancies was found to be an independent risk factor that can improve the performance of exosomal miRNAs in diagnosing PMOP. CONCLUSIONS: These results suggested that the plasma exosomal miRNAs had the potential to serve as noninvasive diagnostic biomarkers for PMOP.

Leaching of structural Ca2+ ions from a chalcogenide adsorbent by H+ lifts Cs(I) uptake.

Acidic wastewater containing radioactive 137Cs is difficult to treat by selective adsorption. Abundant H+ under acidic conditions damages the structure of adsorbents and competes with Cs+ for adsorption sites. Herein, we designed a novel layered calcium thiostannate (KCaSnS) that contains Ca2+ as a dopant. The dopant Ca2+ ion is metastable and larger than the ions attempted before. The pristine KCaSnS demonstrated a high Cs+ adsorption capacity of 620 mg/g at 8250 mg/L Cs+ solution and pH 2, which is 68% higher than that at pH 5.5 (370 mg/g), a trend opposite to all previous studies. The neutral condition allowed the release of Ca2+ present only in the interlayer (∼20%); whereas the high acidity facilitated the leaching of Ca2+ from the backbone structure (∼80%). The complete structural Ca2+ leaching was made possible only by a synergistic interaction of highly concentrated H+ and Cs+. Doping a large enough ion, such as Ca2+, to accommodate Cs+ into the Sn-S matrix upon its liberation opens a new way of designing high-performance adsorbents.

Dittmarite-type magnesium phosphates for highly efficient capture of Cs.

The presence of cesium ions (Cs+) in radioactive wastewater has attracted considerable attention owing to their extreme toxic effects. Thus, there is an urgent need to develop adsorbents for Cs+ with high adsorption capacities (q). While phosphate-based adsorbents have advantages for their disposal, previous adsorbents have shown limited q because of their limited capacity for ion exchange, despite showing high theoretical q values. In this study, two dittmarite-type magnesium phosphates, KMgPO4·H2O (KMP) and NH4MgPO4·H2O (NMP), were synthesized because of their ability to contain readily exchangeable cations in their interlayers. KMP and NMP demonstrated remarkable adsorption capacities for Cs+ (qeKMP = 630 mg g-1 and qeNMP = 711 mg g-1), which were the highest among all reported adsorbents and are ∼84 % of their theoretical values. Their distribution coefficients in waters with high divalent ion concentrations were low, which limits their use for the adsorption of Cs+ from such environments. After adsorption, KMP and NMP were structurally transformed into struvite-type CsMgPO4·6H2O (CsMP), which has two different stacking structures, either cubic or hexagonal, depending on the pH of the solution. The high q values of KMP and NMP enable them to reduce the volume of radioactive waste for disposal.

Diagnosis of nasopharyngeal carcinoma using an ultrasensitive immunoassay method based on nanoparticles.

The detection of the antibody of Epstein-Barr virus (EBV) is critical for the diagnosis of nasopharyngeal carcinoma (NPC). An accurate and scalable point-of-care detection method would support the screening, diagnosis, and monitoring of NPC patients. In this study, firstly, we made an antibody enrichment element, antigen-MNPs, which can screen out specific antibodies in a complex sample. Secondly, signal-amplifying elements were synthesized by labelling inorganic quantum dots (QDs) and anti-antibodies on the surface of flop-ferritin. A sandwich structure is formed among antigen-MNPs, target-antibodies, and anti-antibodies-flop-ferritin@QDs. The antibodies are quantified by fluorescence intensity with a limit of detection (LOD) as low as 10-11 g mL-1. Moreover, the method can detect different types of antibodies and was employed to examine 10 sera from NPC patients and 10 sera from healthy individuals. The result indicates that the simultaneous detection of anti-EBNA-IgG and anti-EBNA-IgA provides an efficient route for early diagnosis of NPC.

Highly selective cesium removal under acidic and alkaline conditions using a novel potassium aluminum thiostannate.

The pH values of nuclear wastewater are extremely low or high, which make the efficient removal of 137Cs a major concern among the issues for safety management and environmental remediation. Existing metal sulfides for Cs+ adsorption have shown poor performance at acidic and alkaline conditions, and the reason has not been revealed yet. Herein, a novel potassium aluminum thiostannate (KAlSnS-3) adsorbent was designed and its Cs+ adsorption mechanism over a wide pH range was investigated. We hypothesized that Al3+ dopant on Sn4+ sites would allow stable adsorption for Cs+ upon its partial release at acidic and alkaline conditions. As a result, KAlSnS-3 demonstrated excellent adsorption performance across a broad pH range (1-13), and high selectivity toward Cs+, even under high salinity conditions (in tap water Kd = 3.12 × 104 mL/g; and in artificial seawater Kd = 3.42 × 103 mL/g). KAlSnS-3 also exhibited rapid adsorption kinetics (R = 97.6% in the first minute), a remarkable adsorption capacity (259.31 mg/g), and a high distribution coefficient (2.09 × 105 mL/g) toward Cs+. In addition, the high reusability of KAlSnS-3 was observed, suggesting its potential for real-world applications. The mechanism for enhancing performance at low and high pH values was discussed with the evidence of crystallinity, elemental concentrations, and binding energy of electrons based on the concept of electrostatic interactions and chemical affinity. In summary, this work provides insights into the mechanism of Cs+ removal under a wide pH range, and the impressive Cs+ adsorption performance indicates the application potential of KAlSnS-3 in wastewater treatment.

Rapid and selective removal of Cs+ from water by layered potassium antimony thiostannate.

137Cs is radioactive and highly hazardous to human health and the environment and its efficient removal from water is still challenging. In this study, potassium antimony tin sulfide (KATS-2) was synthesized using a hydrothermal method and utilized for the first time for cesium removal from water. KATS-2 showed a high maximum ion exchange capacity (358 mg g-1) and distribution coefficient (1.59 × 105 mL g-1) toward Cs+. In particular, KATS-2 showed rapid ion exchange kinetics and reached the adsorption equilibrium within 5 min with 99% removal efficiency. The adsorption was good at a wide active pH range (1-12) even in extreme alkaline conditions (Kd = 3.26 × 104 mL g-1 at pH 12). The effect of coexisting ions was also investigated, and a high selectivity toward Cs+ was maintained even in artificial seawater (Kd = 3.28 × 103 mL g-1). Powder X-ray diffraction and thermogravimetric analysis demonstrated that KATS-2 was chemically and thermally stable. The results showed that owing to its excellent adsorption performance as well as chemical and thermal stability, KATS-2 is a promising adsorbent for Cs+ removal from contaminated water.

Molecular Evidence for Hybrid Origin and Phenotypic Variation of Rosa Section Chinenses.

Rosa sect. Chinenses (Rosaceae) is an important parent of modern rose that is widely distributed throughout China and plays an important role in breeding and molecular biological research. R. sect. Chinenses has variable morphological traits and mixed germplasm. However, the taxonomic status and genetic background of sect. Chinenses varieties remain unclear. In this study, we collected germplasm resources from sect. Chinenses varieties with different morphological traits. Simple sequence repeat (SSR) markers, chloroplast markers, and single copy nuclear markers were used to explore the genetic background of these germplasm resources. We described the origin of hybridization of rose germplasm resources by combining different molecular markers. The results showed that the flower and hip traits of different species in R. sect. Chinenses were significantly different. The SSR analysis showed that the two wild type varieties have different genetic backgrounds. The double petal varieties of R. sect. Chinenses could be hybrids of two wild type varieties. A phylogenetic analysis showed that the maternal inheritance of sect. Chinenses varieties had two different origins. To some extent, variation in the morphological traits of double petal species of R. sect. Chinenses reflects the influence of cultivation process. This study emphasizes that different genetic markers vary in their characteristics. Therefore, analyzing different genetic markers in could provide an insight into highly heterozygous species.