From Lab to Home: Ultrasensitive Rapid Detection of SARS-CoV-2 with a Cascade CRISPR/Cas13a-Cas12a System Based Lateral Flow Assay.

Currently, CRISPR/Cas-based molecular diagnostic techniques usually rely on the introduction of nucleic acid amplification to improve their sensitivity, which is usually more time-consuming, susceptible to aerosol contamination, and therefore not suitable for at-home molecular testing. In this research, we developed an advanced CRISPR/Cas13a-Cas12a-based lateral flow assay that facilitated the ultrasensitive and rapid detection of SARS-CoV-2 RNA directly from samples, without the need for nucleic acid amplification. This method was called CRISPR LFA enabling at-home RNA testing (CLEAR). CLEAR used a novel cascade mechanism with specially designed probes that fold into hairpin structures, enabling visual detection of SARS-CoV-2 sequences down to 1 aM sensitivity levels. More importantly, CLEAR had a positive coincidence rate of 100% and a negative coincidence rate of 100% for clinical nasopharyngeal swabs from 16 patients. CLEAR was particularly suitable for at-home molecular testing, providing a low-cost, user-friendly solution that can efficiently distinguish between different SARS-CoV-2 variants. CLEAR overcame the common limitations of high sensitivity and potential contamination associated with traditional PCR-based systems, making it a promising tool for widespread public health application, especially in environments with limited access to laboratory resources.

Ultra-thin and Mechanically Stable LiCoO2-Electrolyte Interphase Enabled by Mg2+ Involved Electrolyte.

LiCoO2 (LCO) cathode materials have attracted significant attention for its potential to provide higher energy density in current Lithium-ion batteries (LIBs). However, the structure and performance degradation are exacerbated by increasing voltage due to the catastrophic reaction between the applied electrolyte and delithiated LCO. The present study focuses on the construction of physically and chemically robust Mg-integrated cathode-electrolyte interface (MCEI) to address this issue, by incorporating Magnesium bis(trifluoromethanesulfonyl)imide (Mg[TFSI]2) as an electrolyte additive. During formation cycles, the strong MCEI is formed and maintained its 2 nm thickness throughout long-term cycling. Notably, Mg is detected not only in the robust MCEI, but also imbedded in the surface of the LCO lattice. As a result, the parasitic interfacial side reactions, surface phase reconstruction, particle cracking, Co dissolution and shuttling are considerably suppressed, resulting in long-term cycling stability of LCO up to 4.5 V. Therefore, benefit from the double protection of the strong MCEI, the Li||LCO coin cell and the Ah-level Graphite||LCO pouch cell exhibit high capacity retention by using Mg-electrolyte, which are 88.13% after 200 cycles and 90.4% after 300 cycles, respectively. This work provides a novel approach for the rational design of traditional electrolyte additives.

Well-dispersed Pt/Nb2O5on zeolitic imidazolate framework derived nitrogen-doped carbon for efficient oxygen reduction reaction.

In this work, an advanced hybrid material was constructed by incorporating niobium pentoxide (Nb2O5) nanocrystals with nitrogen-doped carbon (NC) derived from ZIF-8 dodecahedrons, serving as a support, referred to as Nb2O5/NC. Pt nanocrystals were dispersed onto Nb2O5/NC using a simple impregnation reduction method. The obtained Pt/Nb2O5/NC electrocatalyst showed high oxygen reduction reaction (ORR) activity due to three-phase mutual contacting structure with well-dispersed Pt and Nb2O5NPs. In addition, the conductive NC benefits electron transfer, while the induced Nb2O5can regulate the electronic structure of Pt element and anchor Pt nanocrystals, thereby enhancing the ORR activity and stability. The half-wave potential (E1/2) for Pt/Nb2O5/NC is 0.886 V, which is higher than that of Pt/NC (E1/2= 0.826 V). The stability examinations demonstrated that Pt/Nb2O5/NC exhibited higher electrocatalytic durability than Pt/NC. Our work provides a new direction for synthesis and structural design of precious metal/oxides hybrid electrocatalysts.

Three-dimensional porous structured cobalt- and nitrogen-doped carbon nanotube electrocatalyst derived from cobalt-based zeolitic imidazolate framework nanoleaves for high performance zinc-air battery.

The development of efficient and cost-effective electrocatalysts to overcome the intrinsic sluggish kinetics of the oxygen reduction reaction (ORR) in zinc-air batteries is crucial. In this study, we introduce a strategy that integrates a template-assisted synthesis with subsequent thermal treatment to fabricate an active and stable cobalt-based nitrogen-doped carbon electrocatalyst, denoted as Co-N-CNT. The strategy adjusts the disordered architecture of the zeolitic imidazolate framework (ZIF) through the synergistic effect of bimetallic species, restricted the growth of zeolitic imidazolate framework nanoleaves (ZIF-L) using salt templates, and directed the transformation from a two-dimensional blade-like morphology to a three-dimensional multi-tiered composite structure. Notably, the Co-N-CNT-800 sample, synthesized at an optimized pyrolysis temperature of 800 °C, exhibits a half-wave potential of 0.89 V and demonstrates stability with sustained cycling over 21 h, which is comparable to the performance of commercial Pt/C electrocatalysts. Moreover, when employed as the cathode in zinc-air batteries, Co-N-CNT-800 not only surpasses Pt/C in terms of power density but also exhibits long-term charge/discharge stability. This findings offer a viable pathway for the design of active and cost-effective ORR electrocatalysts, holding promise for applications in the electrochemical energy storage and conversion systems.

Polypyrrole pre-intercalation engineering-induced NH4+ removal in tunnel ammonium vanadate toward high-performance zinc ion batteries.

Ammonium vanadate with stable bi-layered structure and superior mass-specific capacity have emerged as competitive cathode materials for aqueous rechargeable zinc-ion batteries (AZIBs). Nevertheless, fragile NH…O bonds and too strong electrostatic interaction by virtue of excessive NH4+ will lead to sluggish Zn2+ ion mobility, further largely affects the electro-chemical performance of ammonium vanadate in AZIBs. The present work incorporates polypyrrole (PPy) to partially replace NH4+ in NH4V4O10 (NVO), resulting in the significantly enlarged interlayers (from 10.1 to 11.9 Å), remarkable electronic conductivity, increased oxygen vacancies and reinforced layered structure. The partial removal of NH4+ will alleviate the irreversible deammoniation to protect the laminate structures from collapse during ion insertion/extraction. The expanded interlayer spacing and the increased oxygen vacancies by the virtue of the introduction of polypyrrole improve the ionic diffusion, enabling exceptional rate performance of NH4V4O10. As expected, the resulting polypyrrole intercalated ammonium vanadate (NVOY) presents a superior discharge capacity of 431.9 mAh g-1 at 0.5 A g-1 and remarkable cycling stability of 219.1 mAh g-1 at 20 A g-1 with 78 % capacity retention after 1500 cycles. The in-situ electrochemical impedance spectroscopy (EIS), in-situ X-ray diffraction (XRD), ex-situ X-ray photoelectron spectroscopy (XPS) and ex-situ high resolution transmission electron microscopy (HR-TEM) analysis investigate a highly reversible intercalation Zn-storage mechanism, and the enhanced the redox kinetics are related to the combined effect of interlayer regulation, high electronic conductivity and oxygen defect engineering by partial substitution NH4+ of PPy incorporation.