Spectroscopic, electrochemical, and molecular docking studies of the interaction between the antihistamine drug desloratadine and dsDNA.

Through the utilization of fluorescence spectroscopy, electrochemical, and molecular docking methods, this research investigates the interaction between the antihistamine drug desloratadine and calf thymus double-stranded DNA (ct-dsDNA). Deoxyguanosine (dGuo) and deoxyadenosine (dAdo) oxidation signals were diminished by incubation with varying concentrations of desloratadine, as determined by differential pulse voltammetry (DPV). This change was ascribed to desloratadine's binding mechanism to ct-dsDNA. The binding constant (Kb) between desloratadine and ct-dsDNA was determined to be 2.2 × 105 M-1 throughout electrochemical experiments. In order to further develop our comprehension of the interaction mechanism between desloratadine and ct-dsDNA, a series of spectroscopic experiments and molecular docking simulations were conducted. The Kb value was found to be 8.85 × 104 M-1 at a temperature of 25 °C by the use of fluorescence spectroscopic techniques. In summary, the utilization of electrochemical and spectroscopic techniques, alongside molecular docking investigations, has led to the prediction that desloratadine has the capability to interact with ct-dsDNA by groove binding.

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.

Unraveling the interaction mechanism between orphan drug Nitisinone and bovine serum albumin through spectroscopic and in silico approaches.

The interaction between Nitisinone (NTBC) and bovine serum albumin (BSA) as the transport protein in a circulating system was investigated for the first time utilizing various analytical (UV-Vis spectrophotometry, fluorescence spectroscopy, dynamic light scattering, and differential scanning calorimetry) and computational (molecular docking and molecular dynamics simulations) methods. The BSA fluorescence intensity was quenched upon interaction with NTBC, and the quenching mechanism was observed as static. The interaction between NTBC and BSA was examined at 288 K, 298 K, and 308 K where the binding constants were found to be 1.44 × 105 ± 0.22 M-1, 5.18 × 104 ± 0.20 M-1, and 3.02 × 104 ± 0.22 M-1 respectively, suggesting an intermediate binding affinity between NTBC and BSA. Changes in the microenvironment surrounding tryptophan and tyrosine residues of BSA were elucidated using 3-D fluorescence spectroscopy. Thermodynamic studies revealed the calculated values of ΔH =  - 54.34 ± 5 kJ/mol and ΔS =  - 0.0908 ± 0.24 kJ/mol K-1, indicating the involvement of van der Waals forces and hydrogen bonds in the interaction between NTBC and BSA. Moreover, the interaction's spontaneous nature was evidenced by negative ΔG values across all temperatures. Using dynamic light scattering, it was observed that higher NTBC concentrations led to a gradual rise in hydrodynamic diameter and notable aggregation of the NTBC-BSA complex. Moreover, changing signal values and shifted peaks of BSA, NTBC, and complex in differential scanning calorimetry curves, meant there were molecular interactions between the NTBC and BSA. In silico approaches also elucidated how NTBC binds to active sites on BSA, further supporting other findings. Moreover, molecular docking studies offer a more profound insight into the changing dynamics of hydrophobic, hydrogen, and halogen bonding involved in stabilizing the NTBC-BSA complex.

Development of a new nanosensor for the determination of food coloring Sunset Yellow in powder drinks using L-cysteine coated copper nanoclusters.

Sunset Yellow (SY), which is an artificial azo dye, is preferable for its high stability and low cost. The determination of SY in foods is extremely important for human health because excessive consumption of SY has harmful effects, such as hyperactivity disorder and cancer. In this method, L-cysteine coated copper nanoclusters (CuNCs) were used as a fluorescence probe. L-cysteine has been used as both a reducing and stabilizing agent. One-step green hydrothermal synthesis of CuNCs was made. L-cysteine-coated CuNCs have been characterized using several of methods. CuNCs quenching mechanism is static and inner filter effect (IFE). The linear range is 0.65-14 µg.ml-1 at optimum conditions. LOD and LOQ values were calculated as 0.1 and 0.35 µg.ml-1, respectively. The proposed method was used for the determination of SY in different type of powder drinks. The developed nanosensor is environmentally friendly, easy, fast, reproducible, and low cost.

Fluorometric determination of ornidazole by using BSA coated copper nanoclusters as a novel turn off sensor.

A fluorescent probe based on bovine serum albumin stabilized copper nanoclusters (BSA-CuNCs) was developed for the selective and sensitive determination of ornidazole (ORN). The nanoclusters were synthesized via a one-pot hydrothermal process in basic media. The synthesized and characterized BSA-CuNCs have less than 3 nm particle size and exhibited blue emission at 405 nm when excited at 325 nm. Synthesized and characterized nanoclusters were successfully applied as a turn-off fluorescent probe for the determination of ORN in pharmaceutical dosage forms. The quenching mechanism created an was inner filter effect (IFE). The method was linear in the concentration range of 0.52-13.56 µg mL-1 with a low limit of detection (LOD) 0.01 µg mL-1. High recovery values (98.5%-102.42%) with low RSD% values (0.25%-2.73%) were obtained. The synthesized nanoclusters can be used as a turn-off probe for ORN determination with their selective, simple, rapid, and inexpensive properties.

Highly luminescent water-dispersed silicon quantum dots for fluorometric determination of oxytetracycline in milk samples.

A fluorescent probe based on silicon quantum dots (SiQDs) was developed for the selective and sensitive detection of oxytetracycline (OTC) via the inner filter effect (IFE). The water-soluble fluorescent SiQD was synthesized based on the reaction of 3-Aminopropyltriethoxysilane (APTES) and sodium citrate as precursors by the one-pot hydrothermal process. The strong fluorescence emission of quantum dots (QDs) was obtained at 440 nm when excited at 350 nm and OTC had a broad absorption band between 200 and 400 nm. The excitation spectrum of SiQDs was completely overlapped with the absorption spectrum of OTC. The light at an excitation wavelength of QDs absorbed by OTC caused a decrease in fluorescence intensity with an increase in the concentration of OTC. Under optimal conditions, the linear concentration range was 0.92-9.2 µg mL1 with a detection limit (LOD; S/N = 3) of 0.19 µg mL -1 . The proposed method was applied to the determination of OTC in milk samples and satisfactory recoveries (98.8-100.5%) with low RSD % values (0.93-2.31%) were achieved. This simple, selective, sensitive, rapid, and cheap method can be used as a promising tool for OTC analysis in food safety.

L-Cysteine capped Mn-doped ZnS quantum dots as a room temperature phosphorescence sensor for in-vitro binding assay of idarubicin and DNA.

L-cysteine capped Mn doped ZnS quantum dots/ Idarubicin (IDA) nanohybrids were used as novel room temperature phosphorescence (RTP) sensor to detect double stranded deoxyribonucleic acid (ds-DNA)/drug interaction. IDA, anthracycline derivative anticancer drug, was adsorbed on the surface of the QDs as an electron acceptor to quench the RTP emission. The RTP intensity of QDs was quenched quickly upon addition of quencher and the reaction reached equilibrium within 2 min. The quenching mechanism of phosphorescence of Mn-doped ZnS QDs by IDA is a combined dynamic and static quenching. The static and dynamic quenching constants were found as 1.1×10(5) M(-1) and 8.7×10(4) M(-1), respectively. The addition of ds-DNA caused formation of ds-DNA/IDA complex and recovered the RTP signal of Mn-doped ZnS QDs, which allowed qualitative analysis. Under optimal conditions, RTP intensity of QDs/IDA nanohybrids increased linearly with the concentration of ds-DNA from 1.2 to 6.0 µM. This method is simple, low cost and avoids from interferences.