Trypsin stabilized copper nanoclusters as a highly sensitive and selective probe for fluorescence sensing of morin and temperature

Synthesis of novel phenylalanine-coated copper nanoclusters for fluorescent probes to determine the interactions of cancer drugs with DNA

Abiraterone acetate (ATA) is an FDA-approved prodrug that exerts its effects by irreversibly inhibiting the enzymatic activities of 17α-hydroxylase and C17,20-lyase, which are responsible for testosterone production, particularly. Drug-DNA interaction studies are conducted using various methods. In this study, CuNCs were used as a fluorescent probe for the first time to investigate drug-DNA interactions. Additionally, a new synthesis was developed for copper nanoclusters coated with phenylalanine (Phe). Ascorbic acid served as the reducing agent, while Phe was used as a surface functionalizing and stabilizing agent. Phe/CuNCs were characterized using various techniques including TEM, DLS, XPS, UV-Vis spectroscopy, and fluorescence spectroscopy. Optimization studies were conducted for synthesis parameters such as ascorbic acid concentration, Phe concentration, incubation time, and incubation temperature. This new synthesis method offers various advantages such as easy synthesis procedure, short synthesis time, and compatibility with green chemistry principles. Phe/CuNCs were used as a fluorescent probe for ATA-DNA interactions. The binding constant (Ka) between ATA and DNA was calculated as 1.03 × 104. Furthermore, thermodynamic studies indicated that the effective forces involved in ATA-DNA interaction are Van der Waals and hydrogen bonding.

Rapid and accurate quantification of trypsin activity using integrated infrared and ultraviolet spectroscopy with data fusion techniques

Proteases play a crucial role in industrial enzyme formulations, with activity fluctuations significantly impacting product quality and yield. Therefore, developing a method for precise and rapid detection of protease activity is paramount. This study aimed to develop a rapid and accurate method for quantifying trypsin activity using integrated infrared (IR) and ultraviolet (UV) spectroscopy combined with data fusion techniques. The developed method evaluates the enzymatic activity of trypsin under varying conditions, including temperature, pH, and ionic strength. By comparing different data fusion methods, the study identifies the optimal model for accurate enzyme activity prediction. The results demonstrated significant improvements in predictive performance using the feature-level data fusion approach. Additionally, substituting the spectral data of the samples in the validation sets into the best prediction model resulted in a minimal residual difference between predicted and true values, further verifying the model's accuracy and reliability. This innovative approach offers a practical solution for the efficient and precise quantification of enzyme activity, with broad applications in industrial processes.

One-Pot facile synthesis of fluorescent copper nanoclusters for highly selective and sensitive detection of tetracycline

Due to the excellent characteristics, fluorescent copper nanoclusters (Cu NCs) have aroused great interest in recent years. Herein, the simple prepared, environmentally friendly fluorescent Cu NCs were synthesized by using trypsin as the stabilizer and applied for the determination of tetracycline. Uniformly dispersed Try-Cu NCs were obtained with average size of 3.5 ± 0.3 nm and some excellent merits of good water solubility, UV light stability and salt stability. Emission peaks around 460.0 nm were visibly quenched by tetracycline based on static quenching mechanism and inner filter effect (IFE). Two excellent linear relationships were observed between ln(F0/F) and tetracycline concentrations in the range of 1-100 μM and 100-300 μM with limit of detection (LOD) of 0.084 μM. Meanwhile, this nanoprobe exhibited an apparent selectivity for tetracycline detection. Moreover, Try-Cu NCs were successfully employed to determine tetracycline in serum and milk samples after facile pretreatment with satisfactory recovery rates and credible standard deviation. The results suggested that this as-prepared Try-Cu NCs had excellent application prospects in the future.

Histidine-capped copper nanoclusters for in situ amplified fluorescence monitoring of doxycycline through inner filter effect

There is a significant need to accurately measure doxycycline concentrations in view of the adverse effects of an overdose on human health. A fluorescence (FL) detection method was adopted and copper nanoclusters (CuNCs) were synthesized using chemical reduction technology. Based on FL quenching with doxycycline, the prepared CuNCs were used to explore a fluorescent nanoprobe for doxycycline detection. In an optimal sensing environment, this FL nanosensor was sensitive and selective in doxycycline sensing and displayed a linear relationship in the range 0.5-200 μM with a detection limit of 0.092 μΜ. A characterization test demonstrated that CuNCs offered active functional groups for identifying doxycycline using electrostatic interaction and hydrogen bonds. Static quenching and the inner filter effect (IFE) resulted in weakness in the FL of His@CuNCs with doxycycline with great efficiency. This suggested nanosensor was revealed to be a functional model for simple and rapid detection of doxycycline in real samples with very pleasing accuracy.

Selective determination of ellagic acid in aqueous solution using blue-green emissive copper nanoclusters

Development of beneficial sensors to analyze ellagic acid concentrations is of great importance for food safety and human health. Herein, a facile and fast fluorescent probe was carried out for the excellently selective and sensitive measurement of ellagic acid in real samples through histidine protected copper nanoclusters (histidine@Cu NCs) as a nanosensor. This as-developed histidine@Cu NCs were performed through UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and fluorescence lifetime analysis. The TEM image revealed that this nanomaterial had spherical features with the average diameter of 2.5 ± 0.05 nm. The blue-green fluorescence of this Cu NCs was found under the UV light. Meanwhile, the maximum excitation and emission wavelength were located at 387 nm and 488 nm. After addition of ellagic acid, the fluorescence of histidine@Cu NCs was slowly weakened with excellent linear range of 0.5-300 μM and detection limit of 0.077 μM. The fluorescence weakening mechanism of this nanosensor were attributed to the inner filter effect (IFE) and static quenching. Finally, this as-established analysis platform was successfully employed to measure ellagic acid in real samples.

Preparation of blue fluorescent copper nanoclusters for sensitive and selective sensing of apigenin in pharmaceutical samples

One-pot means was performed for the rapid preparation of copper nanoclusters (Cu NCs), which were employed as a fluorescence system for the sensitive apigenin measurement in pharmaceutical samples. Herein, CuCl₂ aqueous solution was reduced to Cu NCs through ascorbic acid and the Cu NCs were protected through trypsin under 65 ℃ for 4 h. The entire preparation process was rapid, facile and environmentally friendly. The trypsin-capped Cu NCs were demonstrated through ultraviolet-visible spectroscopy, fluorescence spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and fluorescence lifetime, respectively. The Cu NCs revealed blue fluorescence with emission wavelength around 465 nm under the excitation wavelength of 380 nm. The fluorescence weakening feature of Cu NCs with apigenin was observed. On this basis, a facile and sensitive turn-off fluorescent nanoprobe for the sensing of apigenin in real samples was developed. The logarithm of relative fluorescence intensity revealed a good linear relationship with apigenin contents from 0.5 μM to 300 μM with the detection limit of 0.079 μM. The Cu NCs-based fluorescent nanosensor have been employed to measure the apigenin amounts in real samples such as medical saline, bovine and human serum. The results revealed excellent potential of this Cu NCs-based fluorescent nanoprobe for the convention computation of apigenin amounts in real samples.

A novel fluorescent nanoprobe for sensitive detection of 6-thioguanine in human serum based on Cu/Ag nanoclusters

6-Thioguanine (6-TG) is a purine analog anticancer drug used to treat childhood acute leukemia and inflammatory bowel disease; however, the over-dosage use of 6-TG can cause serious adverse effects. Therefore, monitoring the free 6-TG concentration in the human body is critical during drug therapy. In this work, a highly sensitive and rapid fluorescent nanoprobe based on Cu/Ag nanoclusters (NCs) for the detection of 6-TG was developed. The maximum emission wavelength of Cu/Ag NCs was observed at 563 nm with an excitation wavelength of 330 nm. A selective fluorescence quenching effect of 6-TG on the Cu/Ag NCs was found. Under optimum conditions for the determination of 6-TG, a wide linear concentration range from 2.5 to 100 μmol L^-1 was observed with a limit of detection (LOD) of 1.57 μmol L^-1. The characteristics of simple operation, high sensitivity and selectivity make this fluorescent nanoprobe a promising candidate for the detection of 6-TG in biological samples, as demonstrated by the application in spiked human serum with recoveries of 97.6 to 104.8%. In general, this proposed method has good potential for the detection of 6-TG in biological samples.