Single-atom Ni-N4 provides a robust cellular NO sensor

Abstract

Nitric oxide (NO) has been implicated in a variety of physiological and pathological processes. Monitoring cellular levels of NO requires a sensor to feature adequate sensitivity, transient recording ability and biocompatibility. Herein we report a single-atom catalysts (SACs)-based electrochemical sensor for the detection of NO in live cellular environment. The system employs nickel single atoms anchored on N-doped hollow carbon spheres (Ni SACs/N-C) that act as an excellent catalyst for electrochemical oxidation of NO. Notably, Ni SACs/N-C shows superior electrocatalytic performance to the commonly used Ni based nanomaterials, attributing from the greatly reduced Gibbs free energy that are required for Ni SACs/N-C in activating NO oxidation. Moreover, Ni SACs-based flexible and stretchable sensor shows high biocompatibility and low nanomolar sensitivity, enabling the real-time monitoring of NO release from cells upon drug and stretch stimulation. Our results demonstrate a promising means of using SACs for electrochemical sensing applications.

Synthesis Strategies, Catalytic Applications, and Performance Regulation of Single‐Atom Catalysts

“…SACs have sparked tremendous interest as emerging fields owing to their high atom utilization efficiency [ 206,207 ] Whereas, few studies focused on the applications of SACs in biosensing. [ 208–211 ] In a very recent study, Zhu and co‐workers elaborately designed a new type of photoelectrochemical (PEC) biosensing by coupling DNA with SACs, where single‐atom Pt was anchored on the surface of hollow CdS (HCdS‐Pt 1 ) with multienzyme‐encapsulated DNA flowers (DFs) consisted of horseradish peroxidase (HRP) and glucose oxidase (GOx) to enhance selectivity and sensitivity. HRP&GOx‐DFs enriched by target exosome will bio‐etch HCdS‐Pt 1 , which had been used in in situ sensing of exosomes released by the HepG2 cells.…”

“…Besides the widely reported application in these fields described above, SACs have also attracted intensive research interest in both experimental investigations and theoretical calculations, [ 222–225 ] such as water–gas shift (WGS) reaction, [ 210–212,226–228 ] CO oxidation, [ 34,229–231 ] methane conversion, etc. [ 232–235 ]…”

Selectively Probing Neurochemicals in Living Animals with Electrochemical Systems

“…Recently, using nickel single‐atom based electrocatalyst (Figure 3A), Zhou et al. have demonstrated for the first time the SACs facilities NO oxidation and its successful application in real‐time selective NO sensing in live cellular environment (Figure 3B) [27] . Though SACs show great electrocatalytic properties to some of the physiologically relevant chemicals compared to nanocatalysts, the SACs based biosensors have surprisingly been less exploited, probably because of the challenges in controlling over the catalytic activities and biocompatibility of SACs in complexed biosystems.…”

Atomic Nanoarchitectonics for Catalysis

“…Mao and co‐workers reported a flexible sensor based on a Ni single atom catalyst, which can monitor the release of nitrogen monoxide in cells in real time under the stimulation of drugs and stretching ( Figure ). [ 75 ] Using SiO 2 spheres as templates and controlling the weight percentage of dopamine hydrochloride, Ni(acac) 2 and pyrolysis temperature, Ni atoms were successfully anchored to N‐doped hollow carbon spheres (Ni SACs/N–C). Ni atoms are coordinated by N atoms to form Ni–N 4 , providing a good electrical conductivity in the large surface area support.…”