The interactions of dsDNA with new targeted drug delivery derivatives of doxorubicin (DOX), such as DOX embedded into phospholipid nanoparticles (NPhs) and DOX with the NGR targeted peptide-modified NPhs were studied electrochemically by differential pulse voltammetry technique. Screen-printed electrodes (SPEs), modified with stable fine dispersions of carbon nanotubes (CNTs), were used for quantitative electrochemical investigations of direct electrochemical oxidation of guanine, adenine, and thymine heterocyclic bases of dsDNA, and their changes in the presence of DOX nanoderivatives. Analysing the shifts of peak potentials of nucleobases in the presence of drug, we have shown that the doxorubicin with NGR targeted peptide changed the mode of interaction in DNA–drug complexes from intercalative to electrostatic. Binding constants (K_b) of DNA–drug complexes were calculated in accordance with adenine, guanine, and thymine oxidation signals. Based on our experiments, we have proven that the surface modification of a drug delivery system with NGR targeted peptide dramatically changed the mechanism of interaction of drug with genetic material. DNA-mediated drug toxicity was calculated based on the concentration-dependent “response” of heterocyclic nucleobases on drug influence. DOX, DOX-loaded phospholipid nanoparticles (NPhs), and DOX with NGR addressed peptide-modified NPhs were moderately toxic in the concentration range of 0.5–290 µM.

This study is a continuation of an investigation into the effect of a targeted component, a peptide with an NGR, on the properties of the previously developed doxorubicin phospholipid delivery system. The NGR peptide has an affinity for aminopeptidase N (known as the CD13 marker on the membrane surface of tumor cells) and has been extensively used to target drug delivery systems. This article presents the results of a study investigating the physical properties of the phospholipid composition with and without the peptide chain: particle size, zeta potential, stability in fluids, and dependence of doxorubicin release from nanoparticles at different pH levels (5.0, 6.5, 7.4). The cytotoxic effect of the compositions has also been shown to depend on the dose of the drug used for incubation, the presence of the targeted component in the composition, and the time of incubation time of the substances. There was a significant difference in the cytotoxic effect on HT-1080 (CD13-positive) and MCF-7 (CD13-negative) cells. Cell death pathway analysis has shown that death occurred mainly by apoptosis. We also present data on the effect of doxorubicin embedded in phospholipid nanoparticles with the targeted peptide on DNA assessed by differential pulse voltammetry, the mechanism of action being electrostatic interactions. The interactions of native dsDNA with doxorubicin encapsulated in phospholipid nanoparticles with the targeted peptide were studied electrochemically by differential pulse voltammetry. Here, we have highlighted that the targeted peptide in the doxorubicin composition moved specific interaction of the drug with dsDNA from intercalative mode to electrostatic interactions.

An electrochemical method for the determination of the catalytic activity of L-asparaginase (ASNase) from Erwinia carotovora was proposed. Our approach is based on the electrooxidation of amino acids from L-asparaginase polypeptide backbones. The electrochemical behavior of ASNase on electrodes obtained by screen-printing modified with single-wall carbon nanotubes (SPE/SWCNTs) as sensing elements demonstrated a broad oxidation peak at 0.5–0.6 V centered at 0.531 ± 0.010 V. We have shown that in the presence of the substrate L-asparagine, the oxidation current of the enzyme was reduced in a concentration-dependent manner. The specificity of electrochemical analysis was confirmed in experiments with glycine, an amino acid with no substrate activity on ASNase and does not reduce the oxidation peak of L-asparaginase. The addition of glycine did not significantly influence the amplitude of the oxidation current. The innovative aspects of the proposed electrochemical sensor are the direct monitoring of ASNase catalytic activity and a reagentless approach, which does not require additional reagents or labels.

In the present study, the electrochemical behavior of antiviral drug umifenovir (Umi) and umifenovir encapsulated in phospholipids micelles (nanosome/umifenovir, NUmi) were investigated for the first time on screen-printed electrodes modified by carbon nanotubes. We have shown that Umi can be electro oxidized around the potential of +0.4 V in the concentration range of 50–500 µM (R² = 0.992). Non-overlapping signatures of DNA and umifenovir (10–150 µM) permit to register interaction between umifenovir (or umifenovir encapsulated in phospholipids micelles), purine, and pyrimidine heterocyclic bases of DNA separately. The type of interaction is most likely via electrostatic interactions and groove binding in drug-DNA formed complex, as was revealed based on the values of binding constants Kb and the cathodic shifts of oxidation potentials for heterocyclic bases with increasing Umi or NUmi concentration. The negative values of Gibbs free energy (ΔG) for all nucleobases confirm the process spontaneity. This study is the first one presenting the effect of antiviral drug umifenovir and umifenovir encapsulated in phospholipids micelles on dsDNA as a target of pharmacogenomics.

Objectives: The main aim of our experiments was to demonstrate the suitability of cell-based biosensors for searching for new anticancer medicinal preparations. Methods: The effect of the substance doxorubicin, doxorubicin embedded in phospholipid nanoparticles, and doxorubicin with phospholipid nanoparticles modified by targeting vectors (cRGD and folic acid) on dsDNA and breast cancer cell lines (MCF-7, MDA-MB-231) was studied. Results: In the obtained doxorubicin nanoforms, the particle size was less than 60 nm. Our study of the percentage of doxorubicin inclusion showed the almost complete embeddability of the substance into nanoparticles for all samples, with an average of 95.4 ± 4.6%. The calculation of the toxicity index of the studied doxorubicin samples showed that all substances were moderately toxic drugs in terms of adenine and guanine. The biosensor analysis using electrodes modified with carbon nanotubes showed an intercalation interaction between doxorubicin and its derivatives and dsDNA, except for the composition of doxorubicin with folic acid with a linker length of 2000 (NPh-Dox-Fol(2.0)). The results of the electroanalysis were normalized to the total cell protein (mg) and cell concentration. The highest intensity of the electrochemical signals was observed in intact control cells of the MCF-7 and MDA-MB-231 cell lines. Conclusions: The proposed electrochemical approach is useful for the analysis of cell line responses to the medicinal preparations.

Background/Objectives: Our study brings a new method to properly evaluating drug efficacy at the non-invasive in vitro level. Methods: In this work, the electrochemical mediator-free and reagent-free analysis of cell lines based on the registration of electrochemical profiles of membrane proteins was developed. We studied the specificity of cell lines Wi-38 and HepG2 and the toxic effects of drugs on cell-on-electrode systems. Results: A linear dependence of the peak current on the concentration of cells applied to the electrode in the range from 1 × 10⁵ to 6 × 10⁵ cells/electrode was registered (R² 0.932 for Wi-38 and R² 0.912 for HepG2). The water-soluble form of phosphatidylcholine (wPC) nanoparticles recommended for atherosclerosis treatment and prevention of cardiovascular diseases did not show a toxic effect on the human fibroblast cells, Wi-38, or the human hepatocellular carcinoma cells, HepG2, at sufficiently high concentrations (such as 0.1–1 mg/mL). The antitumor drug doxorubicin, at concentrations of 3 and 10 μg/mL, showed a pronounced toxic effect on the tested cell lines, where the percentage of living cells was 50–55%. Conclusions: A comparative analysis of the cytotoxicity of wPC (0.1–1 mg/mL) and doxorubicin (3–10 μg/mL) on the cell lines Wi-38 and HepG2 using the MTT test and electrochemical approach for the registration of cells showed their clear adequacy.