The majority of carcinomas that were developed due to the infection with human papillomavirus (HPV) are caused by high-risk HPV types, HPV16 and HPV18. These HPV types contain the E6 and E7 oncogenes, so the fast detection of these oncogenes is an important point to avoid the development of cancer. Many different HPV tests are available to detect the presence of HPV in biological samples. The aim of this study was to design a fast and low cost method for HPV identification employing magnetic isolation, polymerase chain reaction (PCR) and electrochemical detection. These assays were developed to detect the interactions between E6-HPV16 oncogene and magnetizable particles (MPs) using commercial Dynabeads M-280 Streptavidin particles and laboratory-synthesized “homemade” particles called MANs (MAN-37, MAN-127 and MAN-164). The yields of PCR amplification of E6-HPV16 oncogene bound on the particles and after the elution from the particles were compared. A highest yield of E6-HPV16 DNA isolation was obtained with both MPs particles commercial M-280 Streptavidin and MAN-37 due to reducing of the interferents compared with the standard PCR method. A biosensor employing the isolation of E6-HPV16 oncogene with MPs particles followed by its electrochemical detection can be a very effective technique for HPV identification, providing simple, sensitive and cost-effective analysis. Full article

Liposome-based drug delivery systems hold great potential for cancer therapy. The aim of this study was to design a nanodevice for targeted anchoring of liposomes (with and without cholesterol) with encapsulated anticancer drugs and antisense N-myc gene oligonucleotide attached to its surface. To meet this main aim, liposomes with encapsulated doxorubicin, ellipticine and etoposide were prepared. They were further characterized by measuring their fluorescence intensity, whereas the encapsulation efficiency was estimated to be 16%. The hybridization process of individual oligonucleotides forming the nanoconstruct was investigated spectrophotometrically and electrochemically. The concentrations of ellipticine, doxorubicin and etoposide attached to the nanoconstruct in gold nanoparticle-modified liposomes were found to be 14, 5 and 2 µg·mL⁻¹, respectively. The study succeeded in demonstrating that liposomes are suitable for the transport of anticancer drugs and the antisense oligonucleotide, which can block the expression of the N-myc gene. Full article

In this study a device for automatic electrochemical analysis was designed. A three electrodes detection system was attached to a positioning device, which enabled us to move the electrode system from one well to another of a microtitre plate. Disposable carbon tip electrodes were used for Cd(II), Cu(II) and Pb(II) ion quantification, while Zn(II) did not give signal in this electrode configuration. In order to detect all mentioned heavy metals simultaneously, thin-film mercury electrodes (TFME) were fabricated by electrodeposition of mercury on the surface of carbon tips. In comparison with bare electrodes the TMFEs had lower detection limits and better sensitivity. In addition to pure aqueous heavy metal solutions, the assay was also performed on mineralized rock samples, artificial blood plasma samples and samples of chicken embryo organs treated with cadmium. An artificial neural network was created to evaluate the concentrations of the mentioned heavy metals correctly in mixture samples and an excellent fit was observed (R² = 0.9933). Full article

There is an arising and concerning issue in the field of bacterial resistance, which is confirmed by the number of deaths associated with drug-resistant bacterial infections. The aim of this study was to compare the effects of antibiotics on Staphylococcus aureus non-resistant strain and strains resistant to cadmium or lead ions. Metal resistant strains were created by the gradual addition of 2 mM solution of metal ions (cadmium or lead) to the S. aureus culture. An increasing antimicrobial effect of ampicillin, streptomycin, penicillin and tetracycline (0, 10, 25, 50, 75, 150, 225 and 300 µM) on the resistant strains was observed using a method of growth curves. A significant growth inhibition (compared to control) of cadmium resistant cells was observed in the presence of all the four different antibiotics. On the other hand, the addition of streptomycin and ampicillin did not inhibit the growth of lead resistant strain. Other antibiotics were still toxic to the bacterial cells. Significant differences in the morphology of cell walls were indicated by changes in the cell shape. Our data show that the presence of metal ions in the urban environment may contribute to the development of bacterial strain resistance to other substances including antibiotics, which would have an impact on public health. Full article

Guanine-rich sequences of DNA are able to create tetrastranded structures known as G-quadruplexes; they are formed by the stacking of planar G-quartets composed of four guanines paired by Hoogsteen hydrogen bonding. G-quadruplexes act as ligands for metal ions and aptamers for various molecules. Interestingly, the G-quadruplexes form a complex with anionic porphyrin hemin and exhibit peroxidase-like activity. This review focuses on overview of sensing techniques based on G-quadruplex complexes with anionic porphyrins for detection of various analytes, including metal ions such as K⁺, Ca²⁺, Ag⁺, Hg²⁺, Cu²⁺, Pb²⁺, Sr²⁺, organic molecules, nucleic acids, and proteins. Principles of G-quadruplex-based detection methods involve DNA conformational change caused by the presence of analyte which leads to a decrease or an increase in peroxidase activity, fluorescence, or electrochemical signal of the used probe. The advantages of various detection techniques are also discussed. Full article

In this study, we focused on microfluidic electrochemical analysis of zinc complexes (Zn(phen)(his)Cl₂, Zn(his)Cl₂) and ZnS quantum dots (QDs) using printed electrodes. This method was chosen due to the simple (easy to use) instrumentation and variable setting of flows. Reduction signals of zinc under the strictly defined and controlled conditions (pH, temperature, flow rate, accumulation time and applied potential) were studied. We showed that the increasing concentration of the complexes (Zn(phen)(his)Cl₂, Zn(his)Cl₂) led to a decrease in the electrochemical signal and a significant shift of the potential to more positive values. The most likely explanation of this result is that zinc is strongly bound in the complex and its distribution on the electrode is very limited. Changing the pH from 3.5 to 5.5 resulted in a significant intensification of the Zn(II) reduction signal. The complexes were also characterized by UV/VIS spectrophotometry, chromatography, and ESI-QTOF mass spectrometry. Full article

Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes. Full article

Free radicals are chemical particles containing one or more unpaired electrons, which may be part of the molecule. They cause the molecule to become highly reactive. The free radicals are also known to play a dual role in biological systems, as they can be either beneficial or harmful for living systems. It is clear that there are numerous mechanisms participating on the protection of a cell against free radicals. In this review, our attention is paid to metallothioneins (MTs) as small, cysteine-rich and heavy metal-binding proteins, which participate in an array of protective stress responses. The mechanism of the reaction of metallothioneins with oxidants and electrophilic compounds is discussed. Numerous reports indicate that MT protects cells from exposure to oxidants and electrophiles, which react readily with sulfhydryl groups. Moreover, MT plays a key role in regulation of zinc levels and distribution in the intracellular space. The connections between zinc, MT and cancer are highlighted. Full article