Increasing DNA binding affinity of doxorubicin by loading on Fe3O4 nanoparticles: A multi-spectroscopic study

Modulation of protein-ligand interactions in the presence of ZIF-8: Spectroscopy and molecular dynamics simulation

In this paper, we investigated the protein-ligand interactions in the presence of ZIF-8 using multi-spectroscopic approaches and molecular dynamics simulation. Fluorescence experiments and molecular docking results showed that ZIF-8 did not change the type of quenching and interaction force between ciprofloxacin (CIP) and human serum albumin (HSA), but made the binding constant of HSA-CIP to be smaller, suggesting that ZIF-8 maybe accelerate the dissociation of CIP from HSA-CIP complex. Moreover, the effect of ZIF-8 on the physiological function of HSA was explored. Multi-spectroscopic methods revealed that ZIF-8 did not significantly alter the microenvironment of amino acid groups, but cause a slight decrease in the content of α-helical conformation, and a sparse and flexible structure of the protein backbone. These peculiarities might lead to the diminution of HSA's ability to control drugs. In short, ZIF-8 might enhance drug effect due to affecting the binding of drugs to proteins. However, the present study is only a preliminary investigation of the suitability of ZIF-8 as a drug carrier in vitro, and subsequent in vivo experimental studies will be required to further confirm the idea.

Spectroscopic, calorimetric and cytotoxicity studies on the combined binding of daunorubicin and acridine orange to a DNA tetrahedron

Chemotherapy-phototherapy (CTPT) combination drugs co-loaded by targeted DNA nanostructures can achieve controlled drug delivery, reduce toxic side effects and overcome multidrug resistance. Herein, we constructed and characterized a DNA tetrahedral nanostructure (MUC1-TD) linked with the targeting aptamer MUC1. The interaction of daunorubicin (DAU)/acridine orange (AO) alone and in combination with MUC1-TD and the influence of the interaction on the cytotoxicity of the drugs were evaluated. Potassium ferrocyanide quenching analysis and DNA melting temperature assays were used to demonstrate the intercalative binding of DAU/AO to MUC1-TD. The interactions of DAU and/or AO with MUC1-TD were analyzed by fluorescence spectroscopy and differential scanning calorimetry. The number of binding sites, binding constant, entropy and enthalpy changes of the binding process were obtained. The binding strength and binding sites of DAU were higher than those of AO. The presence of AO in the ternary system weakened the binding of DAU to MUC1-TD. In vitro cytotoxicity studies demonstrated that the loading of MUC1-TD augmented the inhibitory effects of DAU and AO and the synergistic cytotoxic effects of DAU + AO on MCF-7 cells and MCF-7/ADR cells. Cell uptake studies showed that the loading of MUC1-TD was beneficial in promoting the apoptosis of MCF-7/ADR cells due to its enhanced targeting to the nucleus. This study has important guiding significance for the combined application of DAU and AO co-loaded by DNA nanostructures to overcome multidrug resistance.

Interaction of doxorubicin delivered by superparamagnetic iron oxide nanoparticles with DNA

We studied the interaction of superparamagnetic iron oxide nanoparticles (SPIONs), covered by trisodium citrate, with doxorubicin (DOX) and DNA using the spectrophotometric method. We calculated the binding parameters in the binary (DOX-SPION and SPION-DNA) and the ternary (DOX-SPION-DNA) systems. Our studies showed that the nanoparticles do not interact with DNA. We also observed that one nanoparticle loads rather a large number of DOX molecules with a quite high binding constant value (kDOX-SPION = 1.2 × 104 M-1). The DNA addition to the DOX-SPION system induces DOX release from the SPION surface and the formation of DOX-DNA complexes. The presence of nanoparticles has almost no effect on the constant of doxorubicin binding to DNA (kDOX-DNA ≈ 3 × 104 M-1). At high DNA concentrations, almost all DOX molecules bind to DNA. Accordingly, the use of SPIONs as DOX carriers does not require an increased drug dose to achieve a therapeutic effect. Thus, SPIONs are perspective nanocarriers for DOX delivery.

Biosynthesis and Characterization of Co3O4NPs Utilizing Prickly Pear Fruit Extract and its Biological Activities

In the current research, there is a low level of research and information about the interaction of cobalt oxide nanoparticles (Co3O4NPs) in biological systems. This research creates a very simple and cost-effective preparation of cobalt oxide nanoparticles by using prickly pear fruit extract as a reducing agent, which may be further used for biological applications like antimicrobial, antioxidant, DNA interaction and in-vitro anticancer activity. The use of prickly pear fruit extract acts as a good reducing agent and is responsible for easy preparation and reducing the toxicity of cobalt oxide nanoparticles. The fabricated biogenic nanoparticles were confirmed by microscopic and spectroscopic analytical techniques like Ultra Violet-Visible spectrometer, Fourier transforms infrared spectrometer (FTIR), X-ray Diffraction Method (XRD), Energy-dispersive X-ray spectroscopy (EDS), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The average size of the synthesized nanoparticles is 36.24 nm. In the MTT assay, the prepared cobalt oxide NPs haspotential mechanisms of cytotoxicity and in-vitro anticancer activity in Hepatocellular carcinoma cancer cells (HepG2). The microbial activities like antibacterial and antifungal studies of the biosynthesized nanoparticles were performed by the Disc method. The Co3O4NPs with DNA interaction were examined by UV-Visible and fluorescence spectroscopic methods. The binding constant value of biogenic Co3O4NPs with CT-DNA was observed by UV-Visible spectroscopy with a result of 2.57x105mol-1. The binding parameters and quenching constants were observed by fluorescence spectroscopic methods having values of Ksv=7.1x103, kq=7.1x108, Ka=3.47.1x105, n=0.9119. From the findings, Co3O4NPs may be utilized as a medicinal aid for their antibacterial, antifungal, antioxidant, DNA binding and in-vitro anticancer activities.

Metal Cluster Triggered-Assembling Heterogeneous Au-Ag Nanoclusters with Highly Loading Performance and Biocompatible Capability

In this work, we firstly report the preparation of heterogeneously assembled structures Au-Ag nanoclusters (NCs) as good drug carriers with high loading performance and biocompatible capability. As glutathione-protected Au and Ag clusters self-assembled into porous Au-Ag NCs, the size value is about 1.358 (±0.05) nm. The morphology characterization revealed that the diameter of Au-Ag NCs is approximately 120 nm, as well as the corresponding potential ability in loading performance of the metal cluster triggered-assembling process. Compared with individual components, the stability and loading performance of heterogeneous Au-Ag NCs were improved and exhibit that the relative biocompatibility was enhanced. The exact information about this is that cell viability was approximately to 98% when cells were incubated with 100 µg mL−1 particle solution for 3 days. The drug release of Adriamycin from Au-Ag NCs was carried out in PBS at pH = 7.4 and 5.8, respectively. By simulating in vivo and tumor microenvironment, the release efficiency could reach over 65% at pH = 5.8 but less than 30% at pH = 7.2. Using an ultrasound field as external environment can accelerate the assembling process while metal clusters triggered assembling Au-Ag NCs. The size and morphology of the assembled Au-Ag NCs can be controlled by using different power parameters (8 W, 13 W, 18 W) under ambient atmosphere. Overall, a novel approach is exhibited, which conveys assembling work for metal clusters triggers into heterogeneous structures with porous characteristic. Its existing properties such as water-solubility, stability, low toxicity and capsulation can be considered as dependable agents in various biomedical applications and drug carriers in immunotherapies.

Phenylboronic acid-modified polymaleic anhydride-F127 micelles for pH-activated targeting delivery of doxorubicin

Phenylboronic acid (PBA) is a tumor-targeting molecule which selectively recognizes sialic acid (SA) overexpressed in tumors. In the study, PBA, F127 and ethanolamine were conjugated with poly(maleic anhydride) by one-step reaction to form amphiphilic polymer for doxorubicin encapsulation. Two drug-carrying micelles with different mass ratio of polymer to drug were prepared by dialysis method to study effect of PBA on doxorubicin release, tumor-targeting and antitumor activity. The study results showed that doxorubicin release from the formulations was acid-sensitive and affected by the polymer dosage, and its acid-induced release behavior improved its insertion into DNA base pairs. Formulation with high polymer dosage showed better tumor targeting and antitumor activity, and activity of inhibiting HepG2 with higher content of SA-containing glycosphingolipids was higher than that of anti-B16. In vivo studies on the activity of B16-bearing mice showed that the doxorubicin-loaded micelles could inhibit the tumor growth and were safer than free doxorubicin. Thus, the PBA-modified nano-polymer micelles have potential biomedical applications due to their nanostructure and tumor-targeting ability.

Functionalization of Fe3O4/rGO magnetic nanoparticles with resveratrol and in vitro DNA interaction

Based on the previous research, we found that the magnetic nanocomposite Fe₃O₄/rGO (reduced graphene oxide) has a good drug loading effect. Therefore, in this paper, we studied the positive role of Fe₃O₄/rGO as a drug carrier in the interaction between resveratrol (RES) and calf-thymus DNA (ct-DNA). The fluorescence experiment is used to evaluate by the Stern-Volmer equation, the quenching constant of RES - ct-DNA system with and without Fe₃O₄/rGO decreases with the increasing temperature. It was found the quenching mode of RES - ct-DNA and Fe₃O₄/rGO - RES - ct-DNA systems were all static quenching, but the binding constant of RES -ct-DNA increased from 4.14 ± 0.21 × 10⁴ L mol^-1 to 10.12 ± 0.02 × 10⁴ L mol^-1. It was found that Fe₃O₄/rGO formed a ternary complex with RES and ct-DNA by ultraviolet spectrum (UV-vis), resonance light scattering experiments (RLS) and scanning electron microscope (SEM). Meanwhile, Fourier transform infrared (FT-IR) and circular dichroism (CD) experiments show that Fe₃O₄/rGO and Fe₃O₄/rGO loaded with RES have effect on the secondary structure of ct-DNA and change the conformation of ct-DNA. On the cellular level, the comet assay shows that Fe₃O₄/rGO and Fe₃O₄/rGO - RES could not cause DNA strand break to the mouse hepatocytes after 24 co-incubation. These results confirm that Fe₃O₄/rGO nanocomposites have good application potential, which can be used as a good drug carrier in a wide range of therapeutic methods.

Visible-Light-Prompted Synthesis and Binding Studies of 5,6-Dihydroimidazo[2,1-b]thiazoles with BSA and DNA Using Biophysical and Computational Methods

Fused heterocyclic systems containing a bridgehead nitrogen atom have emerged as imperative pharmacophores in the design and development of new drugs. Among these heterocyclic moieties, the imidazothiazole scaffold has long been used in medicinal chemistry for the treatment of various diseases. In this study, we have established a simplistic and environmentally safe regioselective protocol for the synthesis of 5,6-dihydroimidazo[2,1-b]thiazole derivatives from easily available reactants. The reaction proceeds through in situ formation of the α-bromodiketones ensuing trap with imidazolidine-2-thione to provide these versatile bicyclic heterocycles in excellent yields. The synthesized compounds were screened through the molecular docking approach for the most stable complex formation with bovine serum albumin (BSA) and calf thymus deoxyribonucleic acid (ctDNA). The selected compound was further studied using ex vivo binding studies, which revealed moderate interactions with BSA and ctDNA. The binding studies were performed using biophysical approaches including UV-visible spectroscopy, steady-state fluorescence, circular dichroism (CD), and viscosity parameters.

Depicting the DNA Binding and Cytotoxicity Studies against Human Colorectal Cancer of Aquabis (1-Formyl-2-Naphtholato-k2O,O′) Copper(II): A Biophysical and Molecular Docking Perspective

In this study, we attempted to examine the biological activity of the copper(II)–based small molecule aquabis (1-formyl-2-naphtholato-k2O,O′)copper(II) (1) against colon cancer. The characterization of complex 1 was established by analytical and spectral methods in accordance with the single-crystal X-ray results. A monomeric unit of complex 1 exists in an O4 (H2O) coordination environment with slightly distorted square pyramidal geometry (τ = ~0.1). The interaction of complex 1 with calf thymus DNA (ctDNA) was determined by employing various biophysical techniques, which revealed that complex 1 binds to ctDNA at the minor groove with a binding constant of 2.38 × 105 M–1. The cytotoxicity of complex 1 towards human colorectal cell line (HCT116) was evaluated by the MTT assay, which showed an IC50 value of 11.6 μM after treatment with complex 1 for 24 h. Furthermore, the apoptotic effect induced by complex 1 was validated by DNA fragmentation pattern, which clarified that apoptosis might be regulated through the mitochondrial-mediated production of reactive oxygen species (ROS) causing DNA damage pathway. Additionally, molecular docking was also carried out to confirm the recognition of complex 1 at the minor groove.

Doxorubicin Anticancer Drug Monitoring by ds-DNA-Based Electrochemical Biosensor in Clinical Samples

In this research, glassy carbon electrode (GCE) amplified with single-wall carbon nanotubes (SWCNTs) and ds-DNA was fabricated and utilized for voltammetric sensing of doxorubicin with a low detection limit. In this technique, the reduction in guanine signal of ds-DNA in the presence of doxorubicin (DOX) was chosen as an analytical factor. The molecular docking study revealed that the doxorubicin drug interacted with DNA through intercalation mode, which was in agreement with obtained experimental results. The DOX detection performance of ds-DNA/SWCNTs/GCE was assessed at a concentration range of 1.0 nM-20.0 µM. The detection limit was found to be 0.6 nM that was comparable and even better (in many cases) than that of previous electrochemical reported sensors. In the final step, the ds-DNA/SWCNTs/GCE showed powerful ability for determination of the DOX in injection samples with acceptable recovery data.

Insight into the binding mechanism of macrolide antibiotic; erythromycin to calf thymus DNA by multispectroscopic and computational approaches

In the present study, the interactions between Erythromycin drug and calf thymus deoxyribonucleic acid (ct-DNA) were explored by multi spectroscopic techniques (UV-Visible, fluorescence, circular dichroism spectroscopies), viscosity, molecular docking simulation, and atomic force microscopy (AFM). In addition, the values of binding constant were calculated by the UV-Visible and fluorescence spectroscopy. Competitive fluorescence study with methylene blue (MB), acridine orange (AO), and Hoechst 33258 were indicated that the Erythromycin drug could displace the DNA-bound Hoechst, which displays the strong competition of Erythromycin with Hoechst to interact with the groove binding site of DNA. In addition, the observed complexes in AFM analysis comprise the chains of ct-DNA and Erythromycin with an average size of 314.05 nm. The results of thermodynamic parameter calculations (ΔS° = -332.103 ± 14 J mol^-1 K^-1 and ΔH° = -115.839 ± 0.02 kJ mol^-1) approved the critical role of van der Waals forces and hydrogen bonds in the complexation of Erythromycin-DNA. Fluorescence spectroscopy results demonstrate the existence of a static enhancement mechanism in the interaction of Erythromycin-DNA. According to the obtained results, Erythromycin drug interacts with the major groove of ct-DNA. These consequences were further supported by the molecular docking study, and it could be determined that DNA-Erythromycin docked model was in a rough correlation with our experimental results.Communicated by Ramaswamy H. Sarma.

DNA-GEL, Novel Nanomaterial for Biomedical Applications and Delivery of Bioactive Molecules

Novel DNA materials promise unpredictable perspectives for applications in cell biology. The realization of DNA-hydrogels built by a controlled association of DNA nanostars, whose binding can be tuned with minor changes in the nucleotide sequences, has been recently described. DNA hydrogels, with specific gelation properties that can be reassambled in desired culture media supplemented with drugs, RNA, DNA molecules and other bioactive compounds offer the opportunity to develop a novel nanomaterial for the delivery of single or multiple drugs in tumor tissues as an innovative and promising strategy. We provide here a comprehensive description of different, recently realized DNA-gels with the perspective of stimulating their biomedical application. Finally, we discuss the possibility to design sophisticated 3D tissue-like DNA-gels incorporating cell spheroids or single cells for the assembly of a novel kind of cellular matrix as a preclinical investigation for the implementation of tools for in vivo delivery of bioactive molecules.

Preparation and Evaluation of Doxorubicin-Loaded PLA-PEG-FA Copolymer Containing Superparamagnetic Iron Oxide Nanoparticles (SPIONs) for Cancer Treatment: Combination Therapy with Hyperthermia and Chemotherapy

Background

Among the novel cancer treatment strategies, combination therapy is a cornerstone of cancer therapy.

Materials and Methods

Here, combination therapy with targeted polymer, magnetic hyperthermia and chemotherapy was presented as an effective therapeutic technique. The DOX-loaded PLA–PEG–FA magnetic nanoparticles (nanocarrier) were prepared via a double emulsion method. The nanocarriers were characterized by particle size, zeta potential, morphology, saturation magnetizations and heat generation capacity, and the encapsulation efficiency, drug content and in-vitro drug release for various weight ratios of PLA:DOX. Then, cytotoxicity, cellular uptake and apoptosis level of nanocarrier-treated cells for HeLa and CT26 cells were investigated by MTT assay, flow cytometry, and apoptosis detection kit.

Results and Conclusions

The synthesized nanoparticles were spherical in shape, had low aggregation and considerable magnetic properties. Meanwhile, the drug content and encapsulation efficiency of nanoparticles can be achieved by varying the weight ratios of PLA:DOX. The saturation magnetizations of nanocarriers in the maximum applied magnetic field were 59/447 emu/g and 28/224 emu/g, respectively. Heat generation capacity of MNPs and nanocarriers were evaluated in the external AC magnetic field by a hyperthermia device. The highest temperature, 44.2°C, was measured in the nanocarriers suspension at w/w ratio 10:1 (polymer:DOX weight ratio) after exposed to the magnetic field for 60 minutes. The encapsulation efficiency improved with increasing polymer concentration, since the highest DOX encapsulation efficiency was related to the nanocarriers’ suspension at w/w ratio 50:1 (79.6 ± 6.4%). However, the highest DOX loading efficiency was measured in the nanocarriers’ suspension at w/w ratio 10:1 (5.14 ± 0.6%). The uptake efficiency and apoptosis level of nanocarrier-treated cells were higher than those of nanocarriers (folic acid free) and free DOX-treated cells in both cell lines. Therefore, this targeted nanocarrier may offer a promising nanosystem for cancer-combined chemotherapy and hyperthermia.