A study of the interaction tyrosine and DNA using voltammetry and spectroscopy methods

Sequence Does Not Matter: The Biomedical Applications of DNA-Based Coatings and Cores

Biomedical applications of DNA are diverse but are usually associated with specific recognition of target nucleotide sequences or proteins and with gene delivery for therapeutic or biotechnological purposes. However, other aspects of DNA functionalities, like its nontoxicity, biodegradability, polyelectrolyte nature, stability, thermo-responsivity and charge transfer ability that are rather independent of its sequence, have recently become highly appreciated in material science and biomedicine. Whereas the latest achievements in structural DNA nanotechnology associated with DNA sequence recognition and Watson–Crick base pairing between complementary nucleotides are regularly reviewed, the recent uses of DNA as a raw material in biomedicine have not been summarized. This review paper describes the main biomedical applications of DNA that do not involve any synthesis or extraction of oligo- or polynucleotides with specified sequences. These sequence-independent applications currently include some types of drug delivery systems, biocompatible coatings, fire retardant and antimicrobial coatings and biosensors. The reinforcement of DNA properties by DNA complexation with nanoparticles is also described as a field of further research.

Spectroscopic and electrochemical studies of the interaction between oleuropein, the major bio-phenol in olives, and salmon sperm DNA

Interaction of oleuropein, the major bio-phenol in olive leaf and fruit, with salmon sperm double-stranded DNA was investigated by employing electronic absorption titrations, fluorescence quenching spectroscopy, competitive fluorescence spectroscopy, thermal denaturation and voltammetric studies. Titration of oleuropein with the DNA caused a hypochromism accompanied with a red shift indicating an intercalative mode of interaction. Binding constant of 1.4×10(4) M(-1) was obtained for this interaction. From the curves of fluorescence titration of oleuropein with the DNA, binding constant and binding sites were calculated to be 8.61×10(3) M(-1) and 1.05, respectively. Competitive studies with ethidium bromide (a well-known DNA intercalator) showed that the bio-phenol could take the place of ethidium bromide in the DNA intercalation sites. The interaction of oleuropein with DNA was also studied electrochemically. In the presence of the DNA, the anodic and cathodic peak currents of oleuropein decreased accompanied with increases in peak-to-peak potential separation and formal potential, indicating the intercalation of oleuropein into the DNA double helix. Moreover, melting temperature of the DNA was found to increase in the presence of oleuropein, indicating the stabilization of the DNA double helix due to an intercalative interaction.

Spectroscopic study on interaction between three cationic surfactants with different alkyl chain lengths and DNA

In this study, the interaction between cationic surfactants with different alkyl chain lengths, such as hexyltrimethyl ammonium bromide (HTAB), dodecyltrimethyl ammonium bromide (DTAB) and cetyltrimethyl ammonium bromide (CTAB), and DNA was investigated by UV-vis spectroscopy, fluorescence spectroscopy and viscosity techniques. The results showed that these three cationic surfactants with different hydrocarbon chain lengths could all interact with DNA. Their binding modes were estimated and their interaction strength was compared. In addition, the effects of the surfactant, NaCl and phosphate ion concentrations on the interaction were reviewed. It is wished that this work would provide some valuable references to investigate the influence of cationic surfactants with different alkyl chain lengths on DNA.

Studying non-covalent drug-DNA interactions

Drug-DNA interactions have been extensively studied in the recent past. Various techniques have been employed to decipher these interactions. DNA is a major target for a wide range of drugs that may specifically or non-specifically interact with DNA and affect its functions. Interaction between small molecules and DNA are of two types, covalent interactions and non-covalent interactions. Three major modes of non-covalent interactions are electrostatic interactions, groove binding and intercalative binding. This review primarily focuses on discussing various techniques used to study non-covalent interactions that occur between drugs and DNA. Additionally, we report several techniques that may be employed to analyse the binding mode of a drug with DNA. These techniques provide data that are reliable and simple to interpret.

Spectroscopic analyses on interaction of melamine, cyanuric acid and uric acid with DNA

In this work, the interaction of DNA with melamine (MEL), cyanuric acid (CYA) and uric acid (UA) were studied, respectively, by means of UV-vis, fluorescence, circular dichroism (CD) spectroscopy, viscosity and gel electrophoresis methods. The fluorescence quenching was used to study the interaction models of MEL, CYA and UA with DNA, respectively, and the bimolecular quenching constant (Kq), apparent quenching constant (Ksv), effective binding constant (KA) and corresponding dissociation constant (KD) and binding site number (n) were calculated by adopting Stern-Volmer, Lineweaver-Burk and Double logarithm equations. The results show that MEL, CYA and UA are all able to markedly bind to DNA, and the binding strength order is DNA-UA>DNA-CYA>DNA-MEL. It is wished that these researches would facilitate the understanding of the formation of kidney stones and gout in the body after ingesting excess MEL.