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Nitric oxide (NO) is an important radical gaseous signal molecule generated by nitric oxide synthase (NOS) enzymes that participates under various physiological and biological functions and has many roles in signal transduction and cancer therapy. Interestingly, the NO levels which could be maintained by l-arginine (l-arg) and S-nitrosothiols (RSNO) play a vital role in the maintenance of normal physiology functions. However, the controlled production of NO under physiological pH remains a challenge. Herein, we report pH-responsive multifunctional nanoplatforms based on porphyrin (FePor)-decorated cuprous oxide (Cu2O)-encapsulated metal–organic frameworks (ZIF-8) and then modify with poly-l-arginine (P-Arg) for mediating the synthesis of NO. Under acid conditions in tumor, Cu2O/FePor@ZIF-8@Arg is broken down to rapidly release the composite of Cu2O/FePor and P-Arg. Cu2O in the unprotected Cu2O/FePor reacts with RSNO to generate both NO and Cu2+. FePor in Cu2O/FePor could act as artificial enzymes for catalyzing the oxidation of P-Arg to produce NO under physiological pH. The results implied that the efficient production of NO could induce cancer cell apoptosis. The presented strategy supplies a promising method for designing and constructing multifunctional nanoplatforms for the development of NO therapeutic strategy. [ABSTRACT FROM AUTHOR]

S‐Nitrosothiols (RSNOs) which are important intermediates in circulating reservoirs of nitric oxide (NO), transport and numerous NO signaling pathways play intricate roles in the etiology of several pathologies. However, it is still a challenge to control the release of NO from nitrosylated compounds under physiological pH. In this paper, for the first time, we report the catalytic activity and kinetic study for the modulation of NO release from RSNOs by an array of metal‐organic frameworks (MOFs) (M‐MOF (M′); M=Zr, Cu; and M′=Cu, Pd, no metal) under physiological conditions via time‐dependent absorbance spectra. The result showed that metal active sites as well as the morphology and pore size of MOFs exhibited different activities toward RSNOs. The order of catalytic activity of these MOFs toward RSNOs is ordered in the decreasing sequence: Cu‐MOF(Pd)>Cu‐MOF(Cu)>Cu‐MOF(no metal)>Zr‐MOF(Pd)>Zr‐MOF(Cu)>Zr‐MOF(no metal). In addition, Zr‐MOF(Pd) was as model for cell experiment, demonstrated Zr‐MOF(Pd) could react with RSNOs to generate NO in the complex environment of cell. Collectively, these findings establish a platform for MOFs‐based, highly catalyze RSNOs in biological samples, a powerful tool for expanding the knowledge of the biology and chemistry of NO‐mediated phenomena. [ABSTRACT FROM AUTHOR]

S-nitrosothiols (RSNO) as the potential nitric oxide (NO) storage, transfer and delivery vehicles under physiological condition have been identified as important in a number of disease states. However, a detection and quantification of RSNO method with simple and sensitive in biological media is currently lacking. A novel electrochemical sensing platform based on ionic liquid (IL) and copper porphyrin (PorCu) decorated cuprous oxide (Cu 2 O) nanocomposites was developed to detect RSNO under physiological condition. In this system, RSNO were decomposed by Cu(I) in IL/PorCu/Cu 2 O to release NO, following the generated NO could be oxidized on the electrode to generate current signal. By taking advantage of the synergetic effect of IL, PorCu and Cu 2 O, the sensor exhibited excellent sensitivity and linearity toward various RSNO species in phosphate buffer solution (PBS), pH 7.4. A low detection limit for N-Acetyl-3-(nitrososulfanyl)valine (SNAP), S-nitrosocysteine (CysNO) and S-nitrosoglutathione (GSNO) was 110 nM, 20 nM and 67 nM (S/N = 3), respectively. Furthermore, this method displayed good selectivity, which could be used in complex application. The detection scheme with the features of high sensitivity and ease of operation, implies the potential of IL/PorCu/Cu 2 O for further various complex physiological studies., Competing Interests: Declaration of competing interest We declare that we have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)