At-Home COVID-19 Rapid Antigen Test Down to 0.03 pg mL-1 of Nucleocapsid Protein.

Rapid and ultra-sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for early screening and management of COVID-19. Currently, the real-time reverse transcription polymerase chain reaction (rRT-PCR) is the primary laboratory method for diagnosing SARS-CoV-2. It is not suitable for at-home COVID-19 diagnostic test due to the long operating time, specific equipment, and professional procedures. Here an all-printed photonic crystal (PC) microarray with portable device for at-home COVID-19 rapid antigen test is reported. The fluorescence-enhanced effect of PC amplifies the fluorescence intensity of the labeled probe, achieving detection of nucleocapsid (N-) protein down to 0.03 pg mL-1 . A portable fluorescence intensity measurement instrument gives the result (negative or positive) by the color of the indicator within 5 s after inserting the reacted PC microarray test card. The N protein in inactivated virus samples (with cycle threshold values of 26.6-40.0) can be detected. The PC microarray provides a general and easy-to-use method for the timely monitoring and eventual control of the global coronavirus pandemic.

Reversible formation of coordination bonds in Sn-based metal-organic frameworks for high-performance lithium storage.

Sn-based compounds with buffer matrixes possessing high theoretical capacity, low working voltage, and alleviation of the volume expansion of Sn are ideal materials for lithium storage. However, it is challenging to confine well-dispersed Sn within a lithium active matrix because low-melting-point Sn tends to agglomerate. Here, we apply a metal-organic framework (MOF) chemistry between Sn-nodes and lithium active ligands to create two Sn-based MOFs comprising Sn2(dobdc) and Sn2(dobpdc) with extended ligands from H4dobdc (2,5-dioxido-1,4-benzenedicarboxylate acid) to H4dobpdc (4,4'-dioxidobiphenyl-3,3'-dicarboxylate acid) with molecule-level homodispersion of Sn in organic matrixes for lithium storage. The enhanced utilization of active sites and reaction kinetics are achieved by the isoreticular expansion of the organic linkers. The reversible formation of coordination bonds during lithium storage processes is revealed by X-ray absorption fine structure characterization, providing an in-depth understanding of the lithium storage mechanism in coordination compounds.

Coordination compounds in lithium storage and lithium-ion transport.

Lithium-ion batteries (LIBs) have enabled wireless revolution of portable digital products. However, for high-performance applications such as large-scale energy storage and next-generation portable devices, the energy and power densities as well as the cycle life of LIBs still need to be further enhanced. This can be realized by improving the electrochemical performance of the three main components of LIBs: cathode, anode, and electrolyte. In addition to LIBs, lithium-metal batteries (LMBs) have also attracted considerable attention owing to their ultra-high energy density arising from the lithium-metal anode. However, LMB performance is currently limited by dendrite formation and poor interfacial contact between electrode and electrolyte. Herein we highlight the applications of coordination chemistry in LIBs and LMBs, especially for realization of promising next-generation electrode and electrolyte materials based on coordination compounds with well-defined molecular structures. We start by introducing the development of coordination chemistry from discrete coordination compounds to coordination polymers and metal-organic frameworks. Then, we present the design strategies of coordination compounds for lithium storage and lithium-ion transport. Approaches to enhance the electrochemical properties, working potential, capacity, cycling stability, and rate capability of coordination compound-based electrodes are discussed in detail. The reticular chemistry endowing metal-organic frameworks with desired structures and pore metrics as electrolytes for lithium-ion transmission is also summarized. Finally, the current challenges and promising research directions of coordination chemistry for LIBs and LMBs are presented.