Di Wu,Lingxia Qin,Yeping Cen,Jin Lu,Shaohua Ma,Yufang Hu
The necessity for precise delineation and quantitation of pyrophosphatase (PPase) activities is underscored, especially in aggressive prostate cancer, driving the demand for more refined analytical techniques due to challenges associated with inadequate sensitivity and poor signal amplification. In response, a novel electrochemical method utilizing in-situ copper(II) (Cu(II))-based Fast Scan Cyclic Voltammetry (FSCV) is introduced for the advanced detection of PPase in LNCaP prostate cancer cells. This technique is characterized by the exploitation of competitive binding between Cu(II) and L-Phenylalanine (L-Phe) versus pyrophosphate (PPi), with FSCV technology enhanced by ohmic drop compensation to improve detection sensitivity and signal reliability. Through the application of the FSCV technique transitioned to Current(I)-Voltage(V) analysis, the signal generation is facilitated by an L-Phe-Cu(II) complex, driven by the redox reaction of in-situ Cu(II), specifically its rapid transition from the Cu(0) state back to the Cu(II) state. When this complex is anchored onto a gold substrate modified with cucurbit[7]uril (CB[7]) through supramolecular host–guest interactions, a significant FSCV signal is elicited. A detection limit of 0.05 mU/mL (S/N = 3) is subsequently achieved when the method is applied to the quantification of PPase concentration. Leveraging the FSCV method, we have effectively analyzed PPase activity in LNCaP cells, offering a fresh perspective on tumor marker analysis and fostering advancements in drug development.
Dan Li,Jia Jiang,Dandan Han,Xinyu Yu,Kun Wang,Shuang Zang,Dayong Lu,Aimin Yu,Ziwei Zhang
A new method is proposed for measuring the antioxidant capacity by electron spin resonance spectroscopy based on the loss of electron spin resonance signal after Cu2+ is reduced to Cu+ with antioxidant. Cu+ was removed by precipitation in the presence of SCN–. The remaining Cu2+ was coordinated with diethyldithiocarbamate, extracted into n-butanol and determined by electron spin resonance spectrometry. Eight standards widely used in antioxidant capacity determination, including Trolox, ascorbic acid, ferulic acid, rutin, caffeic acid, quercetin, chlorogenic acid, and gallic acid were investigated. The standard curves for determining the eight standards were plotted, and results showed that the linear regression correlation coefficients were all high enough (r > 0.99). Trolox equivalent antioxidant capacity values for the antioxidant standards were calculated, and a good correlation (r > 0.94) between the values obtained by the present method and cupric reducing antioxidant capacity method was observed. The present method was applied to the analysis of real fruit samples and the evaluation of the antioxidant capacity of these fruits.
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