Changes in adenosine triphosphate (ATP) and peroxynitrite (ONOO − ) concentrations have been correlated in a number of diseases including ischemia-reperfusion injury and drug-induced liver injury. Herein, we report the development of a fluorescent probe ATP-LW, which enables the simultaneous detection of ONOO − and ATP. ONOO − selectively oxidizes the boronate pinacol ester of ATP-LW to afford the fluorescent 4-hydroxy-1,8-naphthalimide product NA-OH (λ ex = 450 nm, λ em = 562 nm or λ ex = 488 nm, λ em = 568 nm). In contrast, the binding of ATP to ATP-LW induces the spirolactam ring opening of rhodamine to afford a highly emissive product (λ ex = 520 nm, λ em = 587 nm). Due to the differences in emission between the ONOO − and ATP products, ATP-LW allows ONOO − levels to be monitored in the green channel (λ ex = 488 nm, λ em = 500−575 nm) and ATP concentrations in the red channel (λ ex = 514 nm, λ em = 575−650 nm). The use of ATP-LW as a combined ONOO − and ATP probe was demonstrated using hepatocytes (HL-7702 cells) in cellular imaging experiments. Treatment of HL-7702 cells with oligomycin A (an inhibitor of ATP synthase) resulted in a reduction of signal intensity in the red channel and an increase in that of the green channel as expected for a reduction in ATP concentrations. Similar fluorescence changes were seen in the presence of SIN-1 (an exogenous ONOO − donor).

In this work, we set out to develop an endoplasmic reticulum (ER) directed ESIPT-based ONOO ratiometric fluorescent probe (ABAH-LW). ABAH-LW was synthesized in four steps and found to have a high sensitivity and selectivity towards the detection of ONOO. ABAH-LW was able to detect low concentrations of ONOO (limit of detection = 21.4 nM) within seconds producing a ratiometric change in fluorescence intensity. ABAH-LW further demonstrated the ability to ratiometrically image endogenous and exogenous ONOO in HeLa cells. Moreover, co-localization experiments were carried out using commercially available ER-Tracker Red, Lyso-Tracker Red and Mito-Tracker-Red, which were co-stained with ABAH-LW in HeLa cells. For ER-Tracker Red, Pearson's correlation co-efficient of 0.93 was determined and 3D surface plot analysis illustrated a large overlap between ABAH-LW and ER-Tracker Red using both red and blue channels. In addition some co-localisation with Mito-Tracker Red and ABAH-LW was observed (0.73).

The transition metal-based layered double hydroxides (LDHs) have been extensively studied as promising functional nanomaterials owing to their excellent electrochemical activity and tunable chemical composition. In this work, using acetate anions (Ac–) as intercalating elements, the NiCo-LDH nanosheets arraying on Ni foam with different amounts of Ac– anion intercalation or volume of hydrothermal solution were prepared by a simple hydrothermal method. The optimized amount of Ac– anions expanded the interlayer space of LDH nanosheets from 0.8 to 0.94 nm. An ultrahigh specific capacity of 1200 C g–1 at 1 A g–1 (690 C g–1 without Ac– anions), an outstanding rate capability of 72.5% at 30 A g–1, and a cycle stability of 79.90% after 4500 cycles were mainly attributed to the higher interlayer spacing of Ac– anion intercalation. The enlarged interlayer spacing was beneficial for stabilizing the α-phase of LDHs and accelerating the electron transport and electrolyte penetration in the electrochemical reaction. This work sheds light on the mechanisms of the interlayer spacing regulation of NiCo-LDH nanosheets and offers a promising strategy to synthesize functional nanomaterials with excellent electrochemical performance via integrating their unique layered structure and interlayer anion exchange characteristics.

A new GFP (green fluorescent protein) fluorophore-based probe (Lys-V) was designed and synthesized for mapping lysosomal viscosity in live cells.