Biomaterials are widely used for dental implants, orthopedic devices, cardiac pacemakers and catheters. One of the main concerns on using bio-implants is the risk of infection on the materials used. In this study, our aim is to quantify the effect of controlled surface roughness on the infection resistance of the titanium based bio-materials which are commonly used for orthopedic devices and dental implants. To modify the surface roughness of the surfaces in a controlled manner, Chemical Mechanical Polishing (CMP) technique, which is extensively used in semiconductor industry for the planarization of the interlayer dielectrics and metals, is utilized. To determine the infection resistance of the created films with varying surface roughness, bacteria growth response was studied on titanium plates after CMP.

Surface modification is an important part of fabricating nanoparticles with specific properties and functions. We have designed a dipeptide, which we call NS polypeptide, that consists of four asparagine (N) residues and one serine (S) residue, as a molecule for nanoparticle surface modification. Surface modification of magnetic nanoparticles with the NS polypeptide results in reduction of particle-particle and particle-cell interactions. Here, we describe the surface modification and functionalization of bacterial magnetic particles (BacMPs) by spontaneous integration of temporin L conjugated to NS polypeptide. BacMP membranes were modified temporin L. Furthermore, peptide-modified BacMPs showed high dispersibility in aqueous solution compared to unmodified BacMPs. This surface modification technique may represent a new strategy for reducing non-specific binding of nanoparticles to proteins or cells for use in a variety of protein- or cell-associated applications.

Via the Dissipative Particle Dynamics (DPD) approach, we study the self-assembly of hybrid structures comprising lipids and end-functionalized nanotubes. Individual lipids are composed of a hydrophilic head group and two hydrophobic tails. Each bare nanotube encompasses an ABA architecture, with a hydrophobic shaft (B) and two hydrophilic ends (A). To allow for regulated transport through the nanotube, we also introduce hydrophilic hairs at one end of the tube. The amphiphilic lipids are composed of a hydrophilic head group (A) and two hydrophobic tails (B). We select the dimensions of the nanotube architecture to minimize its hydrophobic mismatch with the lipid bilayer. We find the amphiphilic lipids and functionalized nanotubes to self-assemble into a stable hybrid vesicle or a bicelle in the presence of a hydrophilic solvent. We demonstrate that the morphology of the self-assembled functionalized nanotube-lipid hybrid structures is controlled by the rigidity of the lipid molecules and concentration of the nanotubes.

Corrosion and tribocorrosion tests have been conducted on titanium, Ti-6Al-4V and Ti-10Zr-10Nb-5Ta alloys. The experiments have been conducted in four different electrolytes: NaCl solution, Ringer’s solution, phosphate buffered saline solution (PBS) with and without an addition of bovine serum albumin (BSA).

The electrochemical study showed that, whatever the electrolyte, the passivating film formed on Ti-10Zr-10Nb-5Ta surface is more stable than those obtained on the surface of titanium or Ti-6Al-4V alloy. In addition, Ti-10Zr-10Nb-5Ta presents a better resistance to corrosion. In PBS solution, open circuit potential (OCP) moved to more positive value in comparison with results obtained in NaCl and Ringer’s solutions, whereas addition of BSA moved OCP value towards more negative potential indicating a detrimental effect.

Tribocorrosion tests have been conducted at OCP when sliding against an alumina ball. Friction coefficient, current and volume of material removal at the end of tests have been measured and the results discussed. The influence of the presence of proteins molecules has been particularly analyzed.