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.

Suspended tungsten trioxide (WO3) gate AlGaN/GaN heterostructure deep ultraviolet detectors with integrated micro-heater.

A suspended WO3-gate AlGaN/GaN heterostructure photodetector integrated with a micro-heater is micro-fabricated and characterized for ultraviolet photo detection. The transient optical characteristics of the photodetector at different temperatures are studied. The 2DEG-based photodetector shows a recovery (170 s) time under 240 nm illumination at 150 ℃. The measured spectral response of WO3-gate AlGaN/GaN heterostructure shows a high response in deep ultraviolet range. Responsivity at 240 nm wavelength is 4600 A/W at 0.5 V bias. These characteristics support the feasibility of a high accuracy deep UV detector based on the suspended AlGaN/GaN heterostructure integrated with a micro-heater.

Performance-Enhanced 365 nm UV LEDs with Electrochemically Etched Nanoporous AlGaN Distributed Bragg Reflectors.

A 365-nm UV LED was fabricated based on embedded nanoporous AlGaN distributed Bragg reflectors (DBR) by electrochemical etching. The porous DBR had a reflectance of 93.5% at the central wavelength of 365 nm; this is the highest value of porous AlGaN DBRs below 370 nm which has been reported so far. An innovative two-step etching method with a SiO2 sidewall protection layer (SPL) was proposed to protect the n-AlGaN layer and active region of UV LED from being etched by the electrolyte. The DBR-LED with SPL showed 54.3% improvement of maximal external quantum efficiency (EQE) and 65.7% enhancement of optical power at 100 mA without any degeneration in electrical properties, compared with the un-etched standard LED sample. This work has paved the way for the application of electrically-pumped UV LEDs and VCSELs based on nanoporous AlGaN DBRs.

Inhibitory effect of Scutellariae Radix on hepatic fibrosis based on urinary metabonomic / 中国中药杂志

Urinary metabolomics combined with histological progression were utilized to evaluate the therapeutic effect of Scutellariae Radix decoction and baicalin on hepatic fibrosis (HF) and explore their mechanisms, intervention targets and metabolic pathways. HF rat model was established through subcutaneous injection of CCl₄ for 8 weeks. Meanwhile, different doses of Scutellariae Radix decoction and baicalin were administered. Histomorphology of liver tissue was observed and scored by HE and Masson. Urinary metabonomic analysis based on UPLC-Q-TOF-MS was made for the changes of urinary potential biomarkers among different groups at different time points of HF. Finally, it was found that Scutellariae Radix decoction could improve HF by regulating L-tryptophan, 3-methyldioxyindole, 5-hydroxyindoleacetylglycine, kynurenic acid, 4-(2-amino-3-hydroxyphenyl)-2,4-dioxobutanoic acid, methylmalonic acid and L-leucine. However, baicalin could improve HF by regulating L-tryptophan, 3-methyldioxyindole, 5-hydroxyindoleacetylglycine, 4-(2-amino-3-hydroxyphenyl)-2,4-dioxobutanoic acid, kynurenic acid, and methylmalonic acid. These metabolites involved in tryptophan metabolism and valine, leucine and isoleucine degradation pathways. These results indicated that Scutellariae Radix had the multi-target and multi-pathway characteristics in the treatment of HF. Additionally, low-dose Scutellariae Radix decoction and baicalin are showed better efficacies, with no statistically significant difference between them in histomorphology.