Carboplatin interaction with calf-thymus DNA: A FTIR spectroscopic approach

Synthesis of N-heterocyclic carbene‑selenium complexes modulating apoptosis and autophagy in cancer cells: Probing the interactions with biomolecules and enzymes

Growing cancer resistance is a global threat that calls for development of newer chemotherapeutic analogues especially targeted based therapy to enhance efficacy and selectivity. In this contribution, herein, we report synthesis of selenium incorporated N-heterocyclic carbene (NHC) compounds to explore their potential cytotoxicity against HeLa cells. Test compounds were assured for suitability as drug candidates through physiochemical properties that showed lipophilicity logP 0.85-1.45 for C1-C3 and found stable in biological media (DMEM), whereas, least reactive with N-acetyl cysteine (NAC) and L-glutathione. All the studied compounds showed good cytotoxicity against various cancer strains while compound C1 [3,3-(hexane-1,6-diyl)bis(1-phenethyl-1H-imidazole-2(3H)-selenone)] and C2 [3,3-(hexane-1,6-diyl)bis(1-decyl-1H-imidazole-2(3H)-selenone)] showed promising results with IC50 values of 14.65 ± 0.66 and 8.05 ± 0.35 μg/mL respectively as compared to positive control 21.5 ± 0.05 μg/mL against HeLa cell lines. These compounds showed six-fold higher apoptosis than control with higher accumulation of Ca+ ions intracellularly that alters the expression level of autophagy proteins and increased capase-9 activity. Cell cycle analysis indicated an arrest of cycle in G1 phase of HeLa cells when treated with C1 & C2. Test compounds showed prominent affinity for binding with DNA and inhibiting thioredoxin reductase enzymes in time dependent manners. These findings indicate that Selenium NHC compounds are promising drug candidates to induce cytotoxicity via apoptosis, autophagy and mitochondrial membrane disruptions to manage tumor growth.

Sustainable bioactive hydrogels for organic contaminant elimination in wastewater

Immobilized enzyme bioremediation is a promising technique for eliminating pollutants to alleviate water scarcity pressure but is severely hindered by poor enzymatic activity and stability. An effective charge-assisted H-bonding approach is developed to achieve high laccase loading and enzymatic activity on bio(cellulose)-based hydrogels. Notably, this strategy can be readily extended to lipase and catalase. The bio-based hydrogels are synthesized by grafting deoxyribonucleic acid onto the cellulose backbone through a one-step structural regulation, achieving high mechanical strength, enzyme loading and contaminant capture for degradation. The biocompatible laccase-immobilized hydrogels exhibit significant removal and degradation performance for diverse organic micropollutants, including parent and substituted polycyclic aromatic hydrocarbons, per- and polyfluoroalkyl substances, antibiotics and organic dyes. Further testing focused on parent and substituted polycyclic aromatic hydrocarbons shows minimal influence of various co-existing interfering substances on performance of the laccase-immobilized bioactive hydrogel, with its contaminant removal and degradation efficiency in authentic wastewater being 93.0- and 64.3-fold that of commercial free laccase, respectively. This work provides an effective strategy for sustainable bioremediation of wastewater and other pollutant streams, while simultaneously enabling the development of innovative enzyme catalysts.

Common carp sperm chromatin as an economical and effective remover for benzo(a)pyrene from pollutants

Benzo (a) pyrene is a highly carcinogenic polycyclic aromatic compound, difficult to be degraded, widely present in the environment. However, there is currently no cost-effective and efficient method for removing benzo (a) pyrene. In this study, a feasible method was introduced to cheaply and efficiently adsorb benzo(a)pyrene using chromatin. Scanning electron microscopy analysis showed that the chromatin had a filamentary fiber structure. Fourier transform infrared (FTIR) spectroscopy showed that benzo(a)pyrene formed a bond with the chromatin. Effective binding was confirmed using fluorescence microscopy. Influence factors exploration experiments indicated that the amount of benzo(a)pyrene adsorbed by chromatin was 0.16 mg g-1. The adsorption process of BaP by chromatin is consistent with a pseudo-second-order kinetics model of adsorption. The adsorption isotherm model is consistent with the langmuir isotherm model.This study suggests that chromatin can be utilized as a ordinary and high efficiency adsorbent for removing benzo(a)pyrene and can be utilized in further studies.

Monitoring of DNA structural changes after incorporation of the phenylpyrazole insecticide fipronil

The use of insecticides presents a risk to the environment because they can accumulate in the water, soil, air, and organisms, endangering human and animal health. It is therefore essential to investigate the effects of different groups of insecticides on individual biomacromolecules such as DNA. We studied fipronil, which belongs to the group of phenylpyrazole insecticides. The interaction of fipronil with calf thymus DNA was investigated using spectroscopic methods (absorption and fluorescence spectroscopy) complemented with infrared spectroscopy and viscosity measurement. Fluorescence emission spectroscopy showed the formation of a fipronil/DNA complex with a combined static and dynamic type of quenching. The binding constant was 4.15 × 103 L/mol. Viscosity changes were recorded to confirm/disconfirm the intercalation mode of interaction. A slight change in DNA viscosity in the presence of fipronil was observed. The phenylpyrazole insecticide does not cause significant conformational changes in DNA structure or increase of its chain length. We hypothesize that fipronil is incorporated into the minor groove of the DNA macromolecule via hydrogen interactions as indicated by FT-IR and CD measurements.

Characterization of structural, genotoxic, and immunological effects of methyl methanesulfonate (MMS) induced DNA modifications: Implications for inflammation-driven carcinogenesis

Genotoxic DNA damaging agents are the choice of chemicals for studying DNA repair pathways and the associated genome instability. One such preferred laboratory chemical is methyl methanesulfonate (MMS). MMS, an SN2-type alkylating agent known for its ability to alkylate adenine and guanine bases, causes strand breakage. Exploring the outcomes of MMS interaction with DNA and the associated cytotoxicity will pave the way to decipher how the cell confronts methylation-associated stress. This study focuses on an in-depth understanding of the structural instability, induced antigenicity on the DNA molecule, cross-reactive anti-DNA antibodies, and cytotoxic potential of MMS in peripheral lymphocytes and cancer cell lines. The findings are decisive in identifying the hazardous nature of MMS to alter the intricacies of DNA and morphology of the cell. Structural alterations were assessed through UV-Vis, fluorescence, liquid chromatography, and mass spectroscopy (LCMS). The thermal instability of DNA was analyzed using duplex melting temperature profiles. Scanning and transmission electron microscopy revealed gross topographical and morphological changes. MMS-modified DNA exhibited increased antigenicity in animal subjects. MMS was quite toxic for the cancer cell lines (HCT116, A549, and HeLa). This research will offer insights into the potential role of MMS in inflammatory carcinogenesis and its progression.

A versatile CuCo@PDA nanozyme-based aptamer-mediated lateral flow assay for highly sensitive, on-site and dual-readout detection of Aflatoxin B1

Mycotoxin contaminations in food and environment seriously harms human health. Constructing sensitive and point-of-test early-warning tools for mycotoxin determination is in high demand. In this study, a CuCo@PDA nanozyme-based aptamer-mediated lateral flow assay (Apt-LFA) has been elaborately designed for on-site and sensitive determination of mycotoxin Aflatoxin B1 (AFB1). Benefiting from the rich functional groups and excellent peroxidase-like activity, the CuCo@PDA with original dark color can be conjugated with the specific recognition probe (i.e., aptamer), generating colorimetric signal on the test lines of Apt-LFA via a competitive sensing strategy. The signal can further be amplified in-situ by catalytic chromogenic reaction. Therefore, a visual and dual-readout detection of AFB1 has been realized. The developed Apt-LFA provides a flexible detection mode for qualitative and quantitative analysis of AFB1 by naked-eyes observation or smartphone readout. The smartphone-based LFA platform shows a reliable and ultrasensitive determination of AFB1 with the limit of detection (LOD) of 2.2 pg/mL. The recoveries in the real samples are in the range of 95.11-113.77% with coefficients of variations less than 9.84%. This study provides a new approach to realize point-of-test and sensitive detection of mycotoxins in food and environment using nanozyme-based Apt-LFAs.

Ti3C2Tx MXene-Based Fluorescent Aptasensor for Detection of Dimethoate Pesticide

Dimethoate contaminants in food pose a threat to human health. Rapid and sensitive trace detection methods are required to keep food safe. In this study, a novel fluorescent aptasensor was developed for the sensitive detection of dimethoate based on carbon quantum dots labeled with double-stranded DNA (CQDs-apt-cDNA) and Ti3C2Tx flakes. Under optimal conditions, the aptasensor showed a good linear range of 1 × 10-9 to 5 × 10-5 M for dimethoate with a coefficient of determination (R2) of 0.996. Besides, a low detection limit of 2.18 × 10-10 M was obtained. The aptasensor showed high selectivity in interference samples and good reproducibility with an RSD of 3.06% (<5%) for dimethoate detection. Furthermore, the proposed aptasensor was applied to the detection of dimethoate in apple juice and tap water with satisfactory recoveries from 96.2 to 104.4%. Because of these benefits, this aptasensor has the potential and promise for detecting food contaminants in the food industry.

Efficient removal of ethidium bromide from aqueous solutions using chromatin-loaded chitosan polyvinyl alcohol composites

In this work, a novel chromatin-loaded chitosan polyvinyl alcohol composite was developed as a simple, efficient and environmentally friendly adsorbent for the efficient removal of ethidium bromide (EtBr). SEM images showed that the composites were characterized by dense porous and uniformly distributed morphology. The BET analysis showed the presence of mesopores and macropores in the composites. FTIR and XRD results showed that the chromatin was uniformly dispersed in the chitosan-polyvinyl alcohol carrier through hydrogen bonding. The fluorescence microscopy images showed the change of fluorescence effect before and after the adsorption of the material, which indicated that the chromatin was uniformly distributed in the composites and had a good adsorption effect. The optimal experimental conditions were T = 30℃, t = 120 min, pH = 7.4, m = 0.2 g when the composite with only 5% chromatin content had the ability to adsorb EtBr efficiently (minimum concentration 2 mg·L-1: adsorption rate 99%; maximum concentration 20 mg·L-1: adsorption rate 90%).The adsorption kinetics and thermodynamics showed that the EtBr adsorption kinetics of the composite conformed to the pseudo-second-order kinetic model (0.995 < R2 < 0.999) and the Freundlich isothermal model, and was a spontaneous process (ΔH < 0). This study on the immobilization of chromatin will provide a new way and reference for the application of chromatin in the treatment of EtBr pollutants.

Binding interaction of environmental DNA with typical emerging perfluoroalkyl acids and its impact on bioavailability

As the replacement compounds of perfluoroalkyl acids (PFAAs), emerging PFAAs generally exhibit equal or more hazardous toxicity than legacy PFAAs. Numerous DNA as environmental organic matters coexists with emerging PFAAs, but their interactions and the resulting interaction impacts on the bioavailability of emerging PFAAs remain insufficiently understood. Here, we studied the binding strength and mechanism between DNA and emerging PFAAs (perfluorobutyric acid, perfluorobutylsulfonic acid, and hexafluoropropylene oxide dimer acid) using perfluorooctanoic acid as the control, and further investigated the impacts of DNA binding on the bioavailability of the emerging PFAAs. Isothermal titration calorimetry and quantum chemical calculation found that the emerging PFAAs could bind with DNA bases (main thymine) by van der Waals force and halogen-bond, showing the binding affinities in the range of 7.87 × 104 to L/mol to 6.54 × 106 L/mol. The PFAAs-DNA binding significantly decreased the bioavailability of the PFAAs in both seedlings and plants of pakchoi (Brassica chinensis L.), with little differences in bioavailability change extent among PFAAs. The findings highlight the universality and similarity of the DNA binding effects on PFAAs bioavailability, which can be the natural detoxification mechanism for response to the PFAAs pollution.

Vibrational, Optical, Electrochemical, and Electrical Analysis of Normal and Cancer DNA

In the current article, we did characterizations like Fourier Transform Infrared (FT-IR) Spectroscopy, UV-Visible (UV–vis) spectroscopy, Photoluminescence (PL) spectroscopy, Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), Current-Voltage (I-V) characteristics, dielectric spectroscopy, and transient time spectroscopy on normal and cancerous (esophagus) DNA samples. FT-IR confirms the associated functional groups of DNA. Also a significant change in these groups with mutations is observed. From the analysis of UV data, the various optical parameters like optical band gap, disorder energy were estimated and discussed. PL data demonstrate the various emissions and are described as per the existing structure of the molecule. From the CV plots, the energy levels, like highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were also calculated. The EIS data interpretations show well developed changes in various parameters related with nature of the present molecules. Also from I-V characteristics, visible variations were observed and discussed. From the dielectric spectroscopy, a drastic change in the data were seen and described. Dynamic measurements like transient time demonstrates a vital impact on charge storage and hence on the rise and fall time of the molecules. The various calculated parameters related with these methods show changes with normal and mutated DNA. These observed properties shown by these techniques could be explored for further confirmation of the diagnostic of the disease.

Synthesis, crystallographic, DNA binding, and molecular docking/dynamic studies of a privileged chalcone-sulfonamide hybrid scaffold as a promising anticancer agent

In the present study, a drug-like molecular hybrid structure between chalcone and sulfonamide moieties was synthesized and characterized. The structural peculiarities of the synthesized hybrid were further verified by means of single crystal X-ray crystallography. Furthermore, its biological activity as an anticancer agent was evaluated. The synthesized model of chalcone-sulfonamide hybrid 3 was found to have potent anticancer properties against the studied cancer cell lines. Hence, the in vitro binding interaction of hybrid 3 with Calf thymus DNA (CT-DNA) was studied at a simulated physiological pH to confirm its anticancer activity for the first time. This was investigated by applying different spectroscopic techniques, ionic strength measurements, viscosity measurements, thermodynamics, molecular dynamic simulation and molecular docking studies. The obtained results showed a clear binding interaction between hybrid 3 and CT-DNA with a moderate affinity via a minor groove binding mechanism. The binding constant (Kb) at 298 K calculated from the Benesi-Hildebrand equation was found to be 3.49 × 104 M-1. The entropy and enthalpy changes (ΔS0 and ΔH0) were 204.65 J mol-1 K-1 and 35.08 KJ mol-1, respectively, indicating that hydrophobic interactions constituted the major binding forces. The results obtained from molecular docking and dynamic simulation studies confirmed the minor groove binding interaction and the stability of the formed complex. This study can contribute to further understanding of the molecular mechanism of hybrid 3 as a potential antitumor agent and can also guide future clinical and pharmacological studies for rational drug design with enhanced or more selective activity and greater efficacy.[Figure: see text]Communicated by Ramaswamy H. Sarma.

Polymeric Micelles Formulation of Combretastatin Derivatives with Enhanced Solubility, Cytostatic Activity and Selectivity against Cancer Cells

Combretastatin derivatives is a promising class of antitumor agents, tubulin assembly inhibitors. However, due to poor solubility and insufficient selectivity to tumor cells, we believe, their therapeutic potential has not been fully realized yet. This paper describes polymeric micelles based on chitosan (a polycation that causes pH and thermosensitivity of micelles) and fatty acids (stearic, lipoic, oleic and mercaptoundecanoic), which were used as a carrier for a range of combretastatin derivatives and reference organic compounds, demonstrating otherwise impossible delivery to tumor cells, at the same time substantially reduced penetration into normal cells. Polymers containing sulfur atoms in hydrophobic tails form micelles with a zeta potential of about 30 mV, which increases to 40-45 mV when cytostatics are loaded. Polymers with tails of oleic and stearic acids form poorly charged micelles. The use of polymeric 400 nm micelles provides the dissolution of hydrophobic potential drug molecules. Micelles could significantly increase the selectivity of cytostatics against tumors, which has been shown using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, Fourier transform infrared (FTIR) spectroscopy, flow cytometry and fluorescence microscopy. Atomic force microscopy presented the difference between the unloaded micelles and those loaded with the drug: the size of the former was 30 nm on average, while the latter had a "disc-like" shape and a size of about 450 nm. The loading of drugs into the core of micelles was confirmed by UV and fluorescence spectroscopy methods; shifts of absorption and emission maxima into the long-wavelength region by tens of nm was observed. With FTIR spectroscopy, a high interaction efficiency of micelles with the drug on cells was demonstrated, but at the same time, selective absorption was observed: micellar cytostatics penetrate into A549 cancer cells 1.5-2 times better than the simple form of the drugs. Moreover, in normal HEK293T, the penetration of the drug is reduced. The proposed mechanism for reducing the accumulation of drugs in normal cells is the adsorption of micelles on the cell surface and the preservation of cytostatics to penetrate inside the cells. At the same time, in cancer cells, due to the structural features of the micelles, they penetrate inside, merging with the membrane and releasing the drug by pH- and glutathione-sensitive mechanisms. From a methodological point of view, we have proposed a powerful approach to the observation of micelles using a flow cytometer, which, in addition, allows us to quantify the cells that have absorbed/adsorbed cytostatic fluorophore and distinguish between specific and non-specific binding. Thus, we present polymeric micelles as drug delivery systems in tumors using the example of combretastatin derivatives and model fluorophore-cytostatic rhodamine 6G.

Interactions between Extracellular DNA and Perfluoroalkyl Acids (PFAAs) Decrease the Bioavailability of PFAAs in Pakchoi (Brassica chinensis L.)

Perfluoroalkyl acids (PFAAs) are emerging ionic organic pollutants worldwide. Great amounts of extracellular DNA (∼mg/kg) coexist with PFAAs in the environment. However, PFAA-DNA interactions and effects of such interactions have not been well studied. Herein, we used isothermal titration calorimetry (ITC), spectroscopy, and computational simulations to investigate the PFAA-DNA interactions. ITC assays showed that specific binding affinities of PFHxA-DNA, PFOA-DNA, PFNA-DNA, and PFOS-DNA were 5.14 × 10⁵, 3.29 × 10⁵, 1.99 × 10⁵, and 2.18 × 10⁴ L/mol, respectively, which were about 1-2 orders of magnitude stronger than those of PFAAs with human serum albumin. Spectral analysis suggested interactions of PFAAs with adenine (A), cytosine (C), guanine (G), and thymine (T), among which grooves associated with thymine were the major binding sites. Molecular dynamics simulations and quantum chemical calculations suggested that hydrogen bonds and van der Waals forces were the main interaction forces. Such a PFAA-DNA binding decreased the bioavailability of PFAAs in plant seedlings. The findings will help to improve the current understanding of the interaction between PFAAs and biomacromolecules, as well as how such interactions affect the bioavailability of PFAAs.

Biophysical characterization of structural and conformational changes in methylmethane sulfonate modified DNA leading to the frizzled backbone structure and strand breaks in DNA

Methyl methanesulfonate (MMS) is a highly toxic DNA-alkylating agent that has a potential to damage the structural integrity of DNA. This work employed multiple biophysical and computational methods to report the MMS mediated structural alterations in the DNA (MMS-DNA). Spectroscopic techniques and gel electrophoresis studies revealed MMS induced exposure of chromophoric groups of DNA; methylation mediated anti→syn conformational change, DNA fragmentation and reduced nucleic acid stability. MMS induced single-stranded regions in the DNA were observed in nuclease S1 assay. FT-IR results indicated MMS mediated loss of the assigned peaks for DNA, partial loss of C-O ribose, loss of deoxyribose region, C-O stretching and bending of the C-OH groups of hexose sugar, a progressive shift in the assigned guanine and adenine peaks, loss of thymine peak, base stacking and presence of C-O-H vibrations of glucose and fructose, indicating direct strand breaks in DNA due to backbone loss. Isothermal titration calorimetry showed MMS-DNA interaction as exothermic with moderate affinity. Dynamic light scattering studies pointed towards methylation followed by the generation of single-stranded regions. Electron microscopy pictured the loss of alignment in parallel base pairs and showed the formation of fibrous aggregates in MMS-DNA. Molecular docking found MMS in close contact with the ribose sugar of DNA backbone having non-bonded interactions. Molecular dynamic simulations confirmed that MMS is capable of interacting with DNA at two levels, one at the level of nitrogenous bases and another at the DNA backbone. The study offers insights into the molecular interaction of MMS and DNA.Communicated by Ramaswamy H. Sarma.

Economical gold recovery cycle from bio-sensing AuNPs: an application for nanowaste and COVID-19 testing kits

We report the controlled growth of biologically active compounds: gold nanoparticles (AuNPs) in various shapes, including their green synthesis, characterization, and studies of their applications towards biological, degradation and recycling. Using spectroscopic methods, studies on responsive binding mechanisms of AuNPs with biopolymers herring sperm deoxyribonucleic acid (hsDNA), bovine serum albumin (BSA), dyes degradation study, and exquisitely gold separation studies/recovery from nanowaste, COVID-19 testing kits, and pregnancy testing kits are discussed. The sensing ability of the AuNPs with biopolymers was investigated via various analytical techniques. The rate of degradation of various dyes in the presence and absence of AuNPs was studied by deploying stirring, IR, solar, and UV-Vis methods. AuNPs were found to be the most active cytotoxic agent against human breast cancer cell lines such as MCF-7 and MDAMB-468. Furthermore, an economical process for the recovery of gold traces from nanowaste, COVID-19 detection kits, and pregnancy testing kits was developed using inexpensive and eco-friendly α-cyclodextrin sugar. This method was found to be easy and safest in comparison with the universally accepted cyanidation process. In the future, small gold jewelry makers and related industries would benefit from the proposed gold-recycling process and it might contribute to their socio-economic growth. The methodologies proposed are also beneficial for trace-level forensic investigation.

Multi-spectroscopic, thermodynamic, and molecular docking/dynamic approaches for characterization of the binding interaction between calf thymus DNA and palbociclib

Studying the binding interaction between biological macromolecules and small molecules has formed the core of different research aspects. The interaction of palbociclib with calf thymus DNA at simulated physiological conditions (pH 7.4) was studied using different approaches, including spectrophotometry, spectrofluorimetry, FT-IR spectroscopy, viscosity measurements, ionic strength measurements, thermodynamic, molecular dynamic simulation, and docking studies. The obtained findings showed an apparent binding interaction between palbociclib and calf thymus DNA. Groove binding mode was confirmed from the findings of competitive binding studies with ethidium bromide or rhodamine B, UV–Vis spectrophotometry, and viscosity assessment. The binding constant (K_b) at 298 K calculated from the Benesi–Hildebrand equation was found to be 6.42 × 10³ M⁻¹. The enthalpy and entropy changes (∆H⁰ and ∆S⁰) were − 33.09 kJ mol⁻¹ and 61.78 J mol⁻¹ K⁻¹, respectively, showing that hydrophobic and hydrogen bonds constitute the primary binding forces. As indicated by the molecular docking results, palbociclib fits into the AT-rich region of the B-DNA minor groove with four base pairs long binding site. The dynamic performance and stability of the formed complex were also evaluated using molecular dynamic simulation studies. The in vitro study of the intermolecular binding interaction of palbociclib with calf thymus DNA could guide future clinical and pharmacological studies for the rational drug scheming with enhanced or more selective activity and greater efficacy.

Using biochar to strengthen the removal of antibiotic resistance genes: Performance and mechanism

In this study, the excess activated sludge was used for pyrolysis to produce biochar with Ce modification. The removal process and mechanism of ampicillin resistance gene (ARG_Amp) by biochar was investigated. The results showed that when pyrolyzing the excess sludge at 400 °C, the organic components in the sludge could be partially pyrolyzed and complexed with Ce. By accepting electrons from phenol or quinone, persistent free radicals (PFRs) were formed on the surface of biochar. On the optimized conditions with the initial ARG_Amp concentration of 41.43 mg/L, the removal ratios of ARG_Amp by adsorption, PFRs, hydroxyl free radicals (·OH) by adding H₂O₂ were 28.37%, 8.26%, and 27.56%. No melted DNA was detected in the treated samples. The oxidation process by PFRs and ·OH can directly destroy the ARG_Amp structure. The phosphodiester bond in the base stacking structure and the phosphate bond in the nucleotide are the possible action sites of PFRs. Treated ARG_Amp products were in the form of base pair residues or short-chain double helix structures. ·OH can be added to the bases of nucleotide molecules to form highly active free radical adducts. They can initiate molecular dehydrogenation and intermolecular proton transfer, resulting in oxidation of the base to the scission of the phosphate sugar backbone.

A fluorescence aptasensor based on carbon quantum dots and magnetic Fe3O4 nanoparticles for highly sensitive detection of 17β-estradiol

Trace amounts of 17β-estradiol (E2) in food and the environment poses a threat to human health, which has created the demand for sensitive analytical methods to detect E2. In this study, a novel fluorescent aptasensor was developed for sensitive detection of E2 based on double-chain hybridization between carbon quantum dots-labelled with E2 aptamer (CQDs-aptamer) and Fe₃O₄ nanoparticles modified by complementary DNA (Fe₃O₄-cDNA). Under the optimal conditions, the aptasensor displayed a good linear range of 10^-11-10^-6 M for E2 with the coefficient of determination (R²) of 0.996, and a low detection limit of 3.48 × 10^-12 M was obtained. Besides, the aptasensor showed high selectivity and good reproducibility for E2 detection, which was successfully applied to the sensitive detection of E2 in milk as compared with tap water and lake water with satisfactory recoveries from 85.21% to 114.80%, suggesting the great significance of this aptasensor for detecting food contaminants in the food industry.

Non-covalent binding interaction between phthalic acid esters and DNA

The interaction of phthalic acid esters (PAEs) with DNA is known to be responsible for the disruption of endocrine functions and the teratogenic and carcinogenic effects. However, the binding strength and mechanism of this important process has often been neglected. Here, we confirmed the binding interaction between PAEs and DNA via fluorescence titration quenching experiment. The linear fitting curve proved that PAEs could bind to DNA, and the binding constants (K_A) were 4.11 × 10⁵, 1.04 × 10⁵, 7.60 × 10⁴, 1.99 × 10⁴, and 1.42 × 10³ L/mol for diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), dimethyl phthalate (DMP), and benzyl butyl phthalate (BBP), respectively. DNA melting point, UV-vis spectra and Fourier transform infrared spectroscopy (FTIR) analyses revealed that PAEs interact predominantly with thymines in the DNA minor groove. Quantum chemical calculations showed that hydrogen bonding and van der Waals force formation between PAEs and DNA bases dominated the binding interaction. However, PAEs-DNA binding did not induce any DNA conformation change since the circular dichroism and FTIR spectra of B-DNA were not change. The electrostatic surface potential (ESP) might act an important role in PAEs-DNA binding interaction. This work will broaden our understanding of the interaction between PAEs and genetic materials.

Exploring the interaction of Valsartan and Valsartan-Zn(ll) complex with DNA by spectroscopic and in silico methods

Belonging to the Sartan family, antihypertensive drug - Valsartan (Val) had been found to possess antioxidant properties. Also, the zinc complex of Valsartan (VZn) has been recently recognized as inducing agents of the reductive stress effects thus possessing anticancer activity. Hence, in this work an attempt has been made to understand the interaction of Val and VZn with DNA using spectroscopic and in silico methods as DNA has been identified as the target for many anticancer drugs. VZn has been prepared in 2:1 M ratio and characterised by absorbance, FTIR, HRMS, NMR and Job's continuous variation method. VZn has been tested against human lungs cancer cell line which exhibited good anticancer activity (IC₅₀ = 89 µg/mL). Interaction of Val and VZn with ct-DNA under physiological conditions has been studied by spectroscopic techniques such as fluorescence, absorbance, FTIR, circular dichroism (CD) and in silico methods. Fluorescence quenching, DNA melting and viscometric studies confirmed that both ligand and complex bind to the grooves of the ct-DNA. The experimental results have revealed that VZn strongly bind with DNA compared to Val. Docking study suggested that, Val binds at major groove while VZn binds to both minor and major grooves of B-DNA.

FTIR spectroscopy with machine learning: A new approach to animal DNA polymorphism screening

Technological advances in recent decades, especially in molecular genetics, have enabled the detection of genetic DNA markers associated with productive characteristics in animals. However, the prospection of polymorphisms based on DNA sequencing is still expensive for the reality of many food-producing regions around the world, such as Brazil, demanding more accessible prospecting methods. In the present study, the Fourier transform infrared spectroscopy (FTIR) and machine learning algorithms were used to identify single nucleotide polymorphism (SNP) in animal DNA. The fragments of bovine DNA with well-known polymorphisms were used as a model. The DNA fragments were produced and genotyped by PCR-RFLP and classified according to the genotype (homozygous or heterozygous). FTIR spectra of DNA fragments were analyzed by principal component analysis (PCA) and machine learning algorithms. The best results exhibited 75-95% accuracy in the classification of bovine genotypes. Therefore, FTIR spectroscopy and multivariate analysis can be used as an alternative tool for prospecting polymorphisms in animal DNA. The method can contribute with studies to identify genetic markers associated with animal production and indirectly with food production itself, and reduce pressure on available natural resources.

Binding Force and Site-Determined Desorption and Fragmentation of Antibiotic Resistance Genes from Metallic Nanomaterials

Interfacial interactions between antibiotic resistance genes (ARGs) and metallic nanomaterials (NMs) lead to adsorption and fragmentation of ARGs, which can provide new avenues for selecting NMs to control ARGs. This study compared the adsorptive interactions of ARGs (tetM-carrying plasmids) with two metallic NMs (ca. 20 nm), i.e., titanium dioxide (nTiO₂) and zero-valent iron (nZVI). nZVI had a higher adsorption rate (0.06 min^-1) and capacity (4.29 mg/g) for ARGs than nTiO₂ (0.05 min^-1 and 2.15 mg/g, respectively). No desorption of ARGs from either NMs was observed in the adsorptive background solution, isopropanol or urea solutions, but nZVI- and nTiO₂-adsorbed ARGs were effectively desorbed in NaOH and NaH₂PO₄ solutions, respectively. Molecular dynamics simulation revealed that nTiO₂ mainly bound with ARGs through electrostatic attraction, while nZVI bound with PO₄^3- of the ARG phosphate backbones through Fe-O-P coordination. The ARGs desorbed from nTiO₂ remained intact, while the desorbed ARGs from nZVI were splintered into small fragments irrelevant to DNA base composition or sequence location. The ARG removal by nZVI remained effective in the presence of PO₄^3-, natural organic matter, or protein at environmentally relevant concentrations and in surface water samples. These findings indicate that nZVI can be a promising nanomaterial to treat ARG pollution.

Salmon sperm DNA binding study to cabozantinib, a tyrosine kinase inhibitor: Multi-spectroscopic and molecular docking approaches

In the current work, the binding interaction of cabozantinib with salmon sperm DNA (SS-DNA) was studied under simulated physiological conditions (pH 7.4) using fluorescence emission spectroscopy, UV-Vis absorption spectroscopy, viscosity measurement, ionic strength measurement, FT-IR spectroscopy, and molecular modeling methods. The obtained experimental data demonstrated an apparent binding interaction of cabozantinib with SS-DNA. The binding constant (K_b) of cabozantinib with SS-DNA evaluated from the Benesi-Hildebrand plot was equal to 5.79 × 10⁵ at 298 K. The entropy and enthalpy changes (∆S⁰ and ∆H⁰) in the binding interaction of SS-DNA with cabozantinib were 44.13 J mol^-1 K^-1 and -19.72 KJ mol^-1, respectively, demonstrating that the basic binding interaction forces are hydrophobic and hydrogen bonding interactions. Results from UV-Vis absorption spectroscopy, competitive binding interaction with rhodamine B or ethidium bromide, and viscosity measurements revealed that cabozantinib binds to SS-DNA via minor groove binding. The molecular docking results revealed that cabozantinib fits into the AT-rich region of the B-DNA minor groove and the binding site of cabozantinib was 4 base pairs long. Moreover, cabozantinib has eight active torsions, implying a high degree of flexibility in its structure, which played a significant role in the formation of a stable cabozantinib-DNA complex.

Amino, nitro, chloro, hydroxyl and methyl substitutions may inhibit the binding of PAHs with DNA

The binding of PAHs with DNA to form PAH-DNA adducts is a crucial step in PAH-induced carcinogenesis. How functional groups affect this binding is largely unknown. Here, we observed that functional group substitutions strongly inhibited PAH-DNA binding. Additionally, -OH substitution has the most potent inhibitory effect as it causes the smallest change in the electrostatic surface potential. Fourier transform infrared spectroscopy and molecular docking analyses demonstrated that PAH derivatives bind with guanine via intercalation and groove binding and then non-specifically insert into the major/minor grooves of DNA. Quantum chemical calculations suggested that hydrogen/halogen bonding may be essential in affecting the binding of functional group-substituted PAHs with DNA. It was further revealed that Log K_OA and the PAH derivatives' melting points correlated significantly with binding affinity, implying that changes in the physicochemical characteristics are important factors. This study opens a new window for understanding the relationship between highly toxic PAH derivatives and genetic materials.

Amino and hydroxy substitution influences pyrene-DNA binding

Polycyclic aromatic hydrocarbon (PAH)-DNA binding is an essential step in PAH-induced carcinogenesis. A large number of PAHs contain substituents, it is unclear whether functional groups will influence the PAH-DNA binding. Here, we investigated amino (-NH₂) and hydroxy (-OH) substitution on pyrene-DNA binding. Because of the considerable effects of electrostatic surface potential (ESP), -NH₂ substitution significantly facilitated binding by increasing the binding constant (log K_A) from 4.14 L mol^-1 to 12.31 L mol^-1, while -OH substitution inhibited binding by reducing log K_A to 3.68 L mol^-1. Spectroscopy results revealed that pyrene and its derivatives were able to bind with thymine to induce DNA damage or double helix distortion. Quantum chemical calculations showed that -NH₂ substitution induces hydrogen bond formation, thereby enhancing the binding of pyrene with DNA; moreover, binding force changes due to -OH substitution may not be an essential factor. All structural descriptors were not correlated with the quenching constant (K_SV) or binding constant, indicating that changes in physicochemical properties shows no influence on pyrene-DNA binding. The results of this study will improve our understanding of the contribution of functional groups to PAH-DNA binding.

Label-Free and Regenerable Aptasensor for Real-Time Detection of Cadmium(II) by Dual Polarization Interferometry

Recently, numerous aptamer-based biosensors have been developed to detect heavy metal ions. Most of aptamer-based biosensors only can be used to get some quantitative information. The mechanism of the interaction between aptamer and metal ions, however, is rarely studied. In this work, a label-free and regenerable aptamer-based biosensor was constructed using dual polarization interferometry (DPI). This aptasensor was used to investigate the real-time interaction process between cadmium(II) and its aptamer. According to the information on mass, thickness, and density obtained by DPI, a Cd²⁺ concentration-dependent interaction mechanism and conformation of aptamer was proposed. At low Cd²⁺ concentration, Cd²⁺ mainly interacted with phosphate groups on aptamer, resulting in the stretched ssDNA and a few vertical hairpin structures. When adding the high concentration of Cd²⁺, Cd²⁺ primarily bound with bases of DNA by coordination interaction and the conformation of aptamer transferred to a tight and short hairpin structure. In addition, the association rate constant (k_a), dissociation rate constant (k_d) and disassociation constant (K_D) between Cd²⁺ and its aptamer were calculated to be 96 M^-1 S^-1, 2.11 × 10^-5 S^-1, and 220 nM, respectively. The proposed aptasensor showed high sensitivity for Cd²⁺ detection with the detection limit of 0.61 μg/L, which was far below the 5.0 μg/L ranked by the U.S. Environmental Protection Agency. The biosensor also exhibited excellent regenerability and could be used for three cycles without obvious change in response signal. Therefore, the developed method could not only provide quantitative information, but also offered the information on conformation and kinetics for molecular interaction. This method can facilely extend to study the interaction of DNA with other ions, small molecules, or biomacromolecules.

New minor groove covering DNA binding mode of dinuclear Pt(II) complexes with various pyridine-linked bridging ligands and dual anticancer-antiangiogenic activities

New anticancer platinum(II) compounds simultaneously targeting tumor cells and tumor-derived neoangiogenesis, with new DNA interacting mode and large therapeutic window are appealing alternative to improve efficacy of clinical platinum chemotherapeutics. Herein, we describe three novel dinuclear [{Pt(en)Cl}₂(μ-L)]²⁺ complexes with different pyridine-like bridging ligands (L), 4,4'-bipyridine (Pt1), 1,2-bis(4-pyridyl)ethane (Pt2) and 1,2-bis(4-pyridyl)ethene (Pt3), which highly, positively charged aqua derivatives, [{Pt(en)(H₂O)}₂(μ-L)]⁴⁺, interact with the phosphate backbone forming DNA-Pt adducts with an unique and previously undescribed binding mode, called a minor groove covering. The results of this study suggested that the new binding mode of the aqua-Pt(II) complexes with DNA could be attributed to the higher anticancer activities of their chloride analogues. All three compounds, particularly complex [{Pt(en)Cl}₂(μ-4,4'-bipy)]Cl₂·2H₂O (4,4'-bipy is 4,4'-bipyridine) (Pt1), overcame cisplatin resistance in vivo in the zebrafish-mouse melanoma xenograft model, showed much higher therapeutic potential than antiangiogenic drug sunitinib malate, while effectively blocking tumor neovascularization and melanoma cell metastasis. Overall therapeutic profile showed new dinuclear Pt(II) complexes could be novel, effective and safe anticancer agents. Finally, the correlation with the structural characteristics of these complexes can serve as a useful tool for developing new and more effective anticancer drugs.

Enzymatic degradation of extracellular DNA exposed to chlorpyrifos and chlorpyrifos-methyl in an aqueous system

The persistence of extracellular DNA (eDNA) is crucial for ensuring species diversity and ecological function in aquatic systems. However, scarce information exists about the impact of pesticides on eDNA, although they often co-exist in the aquatic environment. Using a variety of spectroscopic analyses, eDNA degradation and the associated alterations in DNA secondary structure was investigated by exposing DNase I to tested DNA in the presence of chlorpyrifos, a commonly used organophosphate pesticide. Molecular dynamics simulation was used to explore the weak interactions between the tested DNA and chlorpyrifos. The results indicated that chlorpyrifos significantly enhanced DNA degradation without affecting the enzyme activity of DNase I in an aqueous system. Spectroscopic experiments confirmed that chlorpyrifos and the analog chlorpyrifos-methyl could bind with DNA to cause the bases noncovalent stacking interaction. Molecular simulations further demonstrated that pesticide binding with DNA molecules caused widening of the DNA grooves and destruction of the hydrated layer, which enhanced DNA degradation. The findings presented herein provide novel insight into the genotoxicity and ecotoxicity of chlorpyrifos and chlorpyrifos-methyl, as well as their impacts on DNA persistence in aquatic environments.

Fluorescent hybrid nanospheres induced by single-stranded DNA and magnetic carbon quantum dots

Assembled DNA nanospheres were preparedviaself-assembly with magnetic CQDGd as the building blocks and negatively charged ssDNA as the assembly units.

The Application of ATR-FTIR Spectroscopy and the Reversible DNA Conformation as a Sensor to Test the Effectiveness of Platinum(II) Anticancer Drugs

Platinum(II) complexes have been found to be effective against cancer cells. Cisplatin curbs cell replication by interacting with the deoxyribonucleic acid (DNA), reducing cell proliferation and eventually leading to cell death. In order to investigate the ability of platinum complexes to affect cancer cells, two examples from the class of polyfluorophenylorganoamidoplatinum(II) complexes were synthesised and tested on isolated DNA. The two compounds trans-[N,N′-bis(2,3,5,6-tetrafluorophenyl)ethane-1,2-diaminato(1-)](2,3,4,5,6-pentafluorobenzoato)(pyridine)platinum(II) (PFB) and trans-[N,N′-bis(2,3,5,6-tetrafluorophenyl)ethane-1,2-diaminato(1-)](2,4,6-trimethylbenzoato)(pyridine)platinum(II) (TMB) were compared with cisplatin through their reaction with DNA. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy was applied to analyse the interaction of the Pt^(II) complexes with DNA in the hydrated, dehydrated and rehydrated states. These were compared with control DNA in acetone/water (PFB, TMB) and isotonic saline (cisplatin) under the same conditions. Principle Component Analysis (PCA) was applied to compare the ATR-FTIR spectra of the untreated control DNA with spectra of PFB and TMB treated DNA samples. Disruptions in the conformation of DNA treated with the Pt^(II) complexes upon rehydration were mainly observed by monitoring the position of the IR-band around 1711 cm⁻¹ assigned to the DNA base-stacking vibration. Furthermore, other intensity changes in the phosphodiester bands of DNA at ~1234 cm⁻¹ and 1225 cm⁻¹ and shifts in the dianionic phosphodiester vibration at 966 cm⁻¹ were observed. The isolated double stranded DNA (dsDNA) or single stranded DNA (ssDNA) showed different structural changes when incubated with the studied compounds. PCA confirmed PFB had the most dramatic effect by denaturing both dsDNA and ssDNA. Both compounds, along with cisplatin, induced changes in DNA bands at 1711, 1088, 1051 and 966 cm⁻¹ indicative of DNA conformation changes. The ability to monitor conformational change with infrared spectroscopy paves the way for a sensor to screen for new anticancer therapeutic agents.

Insight into Rapid DNA-Specific Identification of Animal Origin Based on FTIR Analysis: A Case Study

In this study, a methodology has been proposed to identify the origin of animal DNA, employing high throughput extension accessory Fourier transform infrared (HT-FTIR) spectroscopy coupled with chemometrics. Important discriminatory characteristics were identified in the FTIR spectral peaks of 51 standard DNA samples (25 from bovine and 26 from fish origins), including 1710, 1659, 1608, 1531, 1404, 1375, 1248, 1091, 1060, and 966 cm⁻¹. In particular, the bands at 1708 and 1668 cm⁻¹ were higher in fish DNA than in bovine DNA, while the reverse was true for the band at 1530 cm⁻¹ was shown the opposite result. It was also found that the PO₂⁻ V_as/V_s ratio (1238/1094 cm⁻¹) was significantly higher (p < 0.05) in bovine DNA than in fish DNA. These discriminatory characteristics were further revealed to be closely related to the base content and base sequences of different samples. Multivariate analyses, such as principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were conducted, and both the sensitivity and specificity values of PLS-DA model were one. This methodology has been further validated by 20 meat tissue samples (4 from bovine, 5 from ovine, 5 from porcine, and 6 from fish origins), and these were successfully differentiated. This case study demonstrated that FTIR spectroscopy coupled with PLS-DA discriminant model could provide a rapid, sensitive, and reliable approach for the identification of DNA of animal origin. This methodology could be widely applied in food, feed, forensic science, and archaeology studies.

Studies of the binding properties of the food preservative thiabendazole to DNA by computer simulations and NMR relaxation

Thiabendazole (TBZ) is a commonly used food preservative and has a wide range of anthelmintic properties. In this study, computer simulations and experiments were conducted to investigate the interaction mechanism of TBZ and herring sperm DNA (hsDNA) at the molecular level. Molecular docking showed that TBZ interacted with DNA in groove mode and bound in A-T and C-G base pair regions. Molecular dynamics (MD) was used to evaluate the stability of the TBZ-DNA complex and found that the three phases in MD and the hydrogen bonds helped maintain the combination. NMR relaxation indicated that TBZ had a certain affinity to hsDNA with a binding constant of 462.43 L mol-1, and the thiazole ring was the main group bound with DNA. Results obtained from fluorescence experiments showed that the binding of TBZ and hsDNA was predominantly driven by enthalpy through a static quenching mechanism. Circular dichroism and viscosity measurements proved the groove binding mode. The FTIR results clarified the conformational changes of DNA, that the DNA helix became shorter and compact, and the DNA structure transformed from B-form to A-form.

Design and synthesis of coumarin-based organoselenium as a new hit for myeloprotection and synergistic therapeutic efficacy in adjuvant therapy

A newly designed organoselenium compound, methyl substituted umbelliferone selenocyanate (MUS), was synthesized as a primary hit against the myelotoxic activity of carboplatin. MUS was administered at 6 mg/kg b.wt, p.o. in concomitant and pretreatment schedules with carboplatin (12 mg/kg b.wt, i.p. for 10 days) in female Swiss albino mouse. MUS treatment reduced (P < 0.001) the percentage of chromosomal aberrations, micronuclei formation, DNA damage and apoptosis in murine bone marrow cells and also enhanced (P < 0.001) the bone marrow cell proliferation of the carboplatin-treated mice. These activities cumulatively restored the viable bone marrow cell count towards normalcy. Myeloprotection by MUS was achieved, in part, due to a significant reduction in the ROS/RNS formation and restoration of glutathione redox pool. Additionally, MUS synergistically enhanced the cytotoxicity of carboplatin against two human cancer cell lines (MCF-7 and Colo-205). Furthermore, MUS can effectively potentiate the antitumour activity of carboplatin against two murine cancers (Dalton's Lymphoma and Sarcoma-180) in vivo. These preclinical findings clearly indicate that MUS can improve the therapeutic index of carboplatin and ensures more effective therapeutic strategy against cancer for clinical development.

hsDNA groove binding, photocatalytic activity, and in vitro breast and colon cancer cell reducing function of greener SeNPs

Selenium nanoparticles (SeNPs) have attracted great attention because of their superior optical properties and wide utilization in biological and biomedical studies. This paper reports an environmentally benign procedure of greener monodispersible SeNP synthesis using the reducing power of Trigonella foenum-graecum extract, characterization and their protective effect against unfolded (Herring sperm DNA) hsDNA. We investigated the anti-cancer activity of SeNPs against MCF-7, MDA MB 435 and COLO-205 cells. The photocatalytic activity of SeNPs was investigated for the degradation of a Sunset Yellow FCF (SYFCF) dye using ultraviolet-B light. The reduction of the Se ion to SeNPs was monitored by ultraviolet-visible spectroscopy (UV-vis). The size and morphology of the SeNPs were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Dynamic Light Scattering (DLS). The SeNPs were stable, and the diameter was homogeneous at around 5-12 nm. Interactions of various concentrations of SeNPs with hsDNA were systematically investigated by UV-vis, fluorescence, circular dichroism (CD), polarimetry and FTIR spectroscopy under physiological conditions. The results from fluorescence spectroscopy indicated that SeNPs quenched the fluorescence intensity of hsDNA with increasing concentrations. The modified Stern-Volmer quenching rate constant Ksv, binding constant K and binding sites n at different temperatures and the corresponding thermodynamic parameters ΔH°, ΔG° and ΔS° were calculated. Hoechst 33258 and methyl green (MG) site markers, melting experiment (Tm), viscosity measurements and sequence specificity verification by DNA bases clarified that SeNPs bind to hsDNA via a groove site. The rate of photocatalytic degradation of the SYFCF dye in the presence and absence of photocatalysts (SeNPs) was studied using UV-vis, the results showed appreciable degradation of the SYFCF dye. Our results suggested that nano Se can be used as a promising selenium species with potential application in cancer treatment. These nanoparticles were found to be the most active cytotoxic agent prepared in a new green synthesis manner, causing >50% inhibition of MCF-7, MDA MB-435 and COLO-205 cell proliferation at concentrations <10(-7) M. Hence these SeNPs could be recognized as promising materials for biomedical applications.

Synthesis and characterisation of arsenic nanoparticles and its interaction with DNA and cytotoxic potential on breast cancer cells

Therapeutic applications of arsenic trioxide (ATO) are limited due to their severe adverse effects. However, nanoparticles of ATO might possess inimitable biologic effects based on their structure and size which differ from their parent molecules. Based on this conception, AsNPs were synthesized from ATO and comparatively analysed for their interaction mechanism with DNA using spectroscopic & electrochemical techniques. Finally, anti-proliferative activity was assessed against different breast cancer cells (MDA-MB-231 & MCF-7) and normal non-cancerous cells (HEK-293). The DNA interaction study revealed that AsNPs and ATO exhibit binding constant values in the order of 10⁶ which indicates strong binding interaction. Binding of AsNPs did not disturb the structural integrity of DNA, on the other hand an opposing effect was observed with ATO through biophysical techniques. Further, in vitro study, confirms cytotoxicity of ATO and AsNPs against different cells, however at particular concentration ATO exhibits more cytotoxicity than that of AsNPs. Furthermore, cytotoxicity was confirmed through acridine orange and comet assay. In conclusion, AsNPs are safer than ATO with comparable efficacy and might be a suitable candidate for the development of novel therapeutic agent against breast cancer and other solid tumours.

Deciphering the intercalative binding modes of benzoyl peroxide with calf thymus DNA

The binding of benzoyl peroxide (BPO), a flour brightener, with calf thymus DNA (ctDNA) was predicted by molecular simulation, and this were confirmed using multi-spectroscopic techniques and a chemometrics algorithm. The molecular docking result showed that BPO could insert into the base pairs of ctDNA, and the adenine bases were the preferential binding sites which were validated by the analysis of Fourier transform infrared spectra. The mode of binding of BPO with ctDNA was an intercalation as supported by the results from ctDNA melting and viscosity measurements, iodide quenching effects and competitive binding investigations. The circular dichroism and DNA cleavage assays indicated that BPO induced a conformational change from B-like DNA structure towards to A-like form, but did not lead to significant damage in the DNA. The complexation was driven mainly by hydrogen bonds and hydrophobic interactions. Moreover, the ultraviolet-visible (UV-vis) spectroscopic data matrix was resolved by a multivariate curve resolution-alternating least-squares algorithm. The equilibrium concentration profiles for the components (BPO, ctDNA and BPO-ctDNA complex) were extracted from the highly overlapping composite response to quantitatively monitor the BPO-ctDNA interaction. This study has provided insights into the mechanism of the interaction of BPO with ctDNA and potential hazards of the food additive.