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.

Quantum Chemistry Estimation of Adhesion Strength of Hydroxyapatite with Titanium Substrate

One of the ways to improve the fusion of an implant with bone tissue is through the use of biocompatible coatings, in particular, hydroxyapatite (HAp). It is important to assess the strength of the HAp adhesion to the implant. The measure of the strength of the bond of the coating with the substrate is the energy of this bond. Using density functional theory and molecular dynamics, the reaction path, reaction products, oscillation frequency, activation energy and bond energy between different combinations of component anions HAp and Ti (II) – the standard material of implants – are calculated. Using the computational chemistry software suite Gaussian 09 (Revision C.01 was used), the stable configurations of the reactants and products are found, and the binding energy of hydroxyapatite and titanium is then calculated based on the difference in ground energy of reactants and ground energy of products. Thus, the method of adhesion strength estimation between HAp coatings and Ti is proposed based on numerical calculations using MD software, and suggestions are provided on which conditions would be the best for optimal binding strength.

The Effect of Synthesis Parameters on the Size, Composition, and Stability of Iron Nanoparticles

Magnetic nanoparticles (MNPs) have many uses for biomedical applications including drug delivery, magnetic resonance imaging (MRI) contrast agents, theranostics and hyperthermia. MNPs photo-thermally heated by laser light could be used to treat the typically difficult to access tumors such as glioblastomas. Due to their high magnetic saturation, monometallic iron nanoparticles would have an edge over iron oxide nanoparticles currently being investigated for hyperthermia. The goal of this study was to synthesize spherical iron nanoparticles less than 10 nm in diameter by thermal decomposition. The ability of various biocompatible coatings to protect the metallic iron nanoparticles from oxidation was investigated. Coatings studied included Brij, polyethylene glycol and iron oxide. Transmission electron microscopy and Mössbauer spectroscopy were utilized to characterize the coated and uncoated iron nanoparticles’ size and oxidation state to evaluate the effectiveness of the coatings and the procedures in which the coatings were applied. A ferrite shell was found to provide the best stabilization; however, its longer synthesis time increased particle size distribution. Polymer coatings provided biocompatibility but did not prevent oxidation.

Formation of PEO-Coatings for Implants Materials

The paper presents results of investigation of biocompatible coatings on VT1-0 commercially pure titanium formed using plasma electrolytic oxidation (PEO) method. The effects of samples with different surface treatment on the functional activity of cells innate immunity have been studied. The study of enzymes has showed the higher stimulation of cellular metabolism during the first hour of contact with the PEO-coating in comparison with the uncoated titanium. The smallest immunostimulatory influence has been obtained for PEO-coating. It has been established that PEO-layers on titanium affect the functional state of cellular processes accompanying bone mineralization.

ROBOTIC PLASMA SPRAYING SYSTEM FOR IMPLANTS OF COMPLEX STRUCTURE: 3D MODEL AND MOTION PLANNING

The problem of a robotic system creating for plasma spraying of biocompatible coatings on complex shaped implants based on a Fanuc LR Mate 200 id manipulation robot and modeling spraying trajectories using a virtual simulator Roboguide V6.40 is considered. Parametric classification of implants is carried out whenever possible by plasma spraying using robotic devices. The main procedures for implants preparation for spraying were investigated. The 3D UNIVERSE scanner is used for scanning the implant and building its spatial model, the 3D model of the implant is being developed in Geomagic Design X. To build the manipulator program movements taking into account the speed of movement, it is proposed to use fourth order splines, which is built in the Matlab tools with finding of the optimal close spline to the original values. As the example of Cox femoral joint implant, a simulation of robot motion is performed using a virtual simulator Roboguide V6.40 with the possibility of transferring the program to a real Fanuc LR Mate 200 id robot.

Biomimetic Coatings Obtained by Combinatorial Laser Technologies

The modification of implant devices with biocompatible coatings has become necessary as a consequence of premature loosening of prosthesis. This is caused mainly by chronic inflammation or allergies that are triggered by implant wear, production of abrasion particles, and/or release of metallic ions from the implantable device surface. Specific to the implant tissue destination, it could require coatings with specific features in order to provide optimal osseointegration. Pulsed laser deposition (PLD) became a well-known physical vapor deposition technology that has been successfully applied to a large variety of biocompatible inorganic coatings for biomedical prosthetic applications. Matrix assisted pulsed laser evaporation (MAPLE) is a PLD-derived technology used for depositions of thin organic material coatings. In an attempt to surpass solvent related difficulties, when different solvents are used for blending various organic materials, combinatorial MAPLE was proposed to grow thin hybrid coatings, assembled in a gradient of composition. We review herein the evolution of the laser technological process and capabilities of growing thin bio-coatings with emphasis on blended or multilayered biomimetic combinations. These can be used either as implant surfaces with enhanced bioactivity for accelerating orthopedic integration and tissue regeneration or combinatorial bio-platforms for cancer research.