Integrated Graphene Oxide Purification-Lateral Flow Test Strips (iGOP-LFTS) for Direct Detection of PCR Products with Enhanced Sensitivity and Specificity

An integrated graphene oxide purification-lateral flow test strip (iGOP-LFTS) was developed for on-strip purifying and visually detecting polymerase chain reaction (PCR) products with an improved sensitivity as well as a more stringent specificity. PCR products amplified with a pair of biotin- and digoxin-labeled primers were directly pipetted onto GO pads, on which graphene oxide selectively adsorbed residual primers and primer-dimers with the aid of a running buffer containing MgCl₂ and Tween 20. By stacking up three GO pads to increase the surface area for adsorption, 83.4% of double-stranded DNA with a length of 30 bp and 98.6% of 20-nt primers could be removed from a 10-μL DNA mixture. Since no primers interfered with detection, the increase of the sample loading volume from 5 to 20 μL could improve the signal-to-noise ratio of the test line 1.6 fold using the iGOP-LFTS while no changes were observed using the conventional LFTS. The limit of detection of the iGOP-LFTS was determined to be 30 copies of bacteriophage λ-DNA with naked eyes and this limit could be further decreased to 3 copies by loading 20 μL of the sample, which corresponded to a 1000-fold improvement compared to that of the LFTS detected by naked eyes. When the ImageJ analysis was employed, a 100-fold decrease of the detection limit can be obtained. In addition, due to the removal of the primer-dimers, the dim test line observed in the negative control of the LFTS was eliminated using the iGOP-LFTS. A mock clinical specimen spiked with defective HIV-1 (human immunodeficiency virus) viruses was successfully analyzed using a two-step reverse transcription-PCR with 30 amplification cycles followed by the iGOP-LFTS detection. These significant improvements were achieved without introducing any additional hands-on operations and instrumentations

Enhancing Li–S Battery Performance with Limiting Li[N(SO₂F)₂] Content in a Sulfolane-Based Sparingly Solvating Electrolyte

By enhancing the stability of the lithium metal anode and mitigating the formation of lithium dendrites through electrolyte design, it becomes feasible to extend the lifespan of lithium–sulfur (Li–S) batteries. One widely accepted approach involves the utilization of Li[N(SO2F)2] (Li[FSA]), which holds promise in stabilizing the lithium anode by facilitating the formation of an inorganic-dominant solid electrolyte interface (SEI) film. However, the use of Li[FSA] encounters limitations due to inevitable side reactions between lithium polysulfides (LiPSs) and [FSA] anions. In this study, our focus lies in precisely controlling the composition of the SEI film and the morphology of the deposited lithium, as these two critical factors profoundly influence lithium reversibility. Specifically, by subjecting an initial charging process to an elevated temperature, we have achieved a significant enhancement in lithium reversibility. This improvement is accomplished through the employment of a LiPS sparingly solvating electrolyte with a restricted Li[FSA] content. Notably, these optimized conditions have resulted in an enhanced cycling performance in practical Li–S pouch cells. Our findings underscore the potential for improving the cycling performance of Li–S batteries, even when confronted with challenging constraints in electrolyte design

Survival of islet allografts from the donors of WT mice and PD L1-deficient mice.

<p>Blood glucose levels and islet graft survival in the recipients bearing islets from WT mice and PDL1- deficient mice are shown (N = 8). Diabetes was induced in BALB/c mice with STZ, followed by transplantation of four hundred islets isolated from WT or PDL1- deficient mice. The blood glucose levels are shown in Fig 2A in comparison with the glucose levels of the recipients transplanted with the islets from WT mice. Euglycemia was maintained for a shorter duration in the recipients bearing islets from PD-L1-deficient mice (Fig 2B). Graft survival was calculated by the Kaplan-Meier method and compared using a log-rank test (P = 0.0008). The results show that the survival time of the recipients transplanted with islets from PD-L1-deficient mice was clearly shorter compared with that of the recipients bearing islets from WT mice.</p