Evaluation of microbial adhesion and biofilm formation on nano-structured and nano-coated ortho-prosthetic materials by a dynamic model

The bio-engineering technologies of medical devices through nano-structuring and coating was recently proposed to improve biocompatibility and to reduce microbial adhesion in the prevention of implantable device-related infections. Our aim was to evaluate the ability of new nano-structured and coated materials to prevent the adhesion and biofilm formation, according to the American Standard Test Method ASTM-E2647-13. The materials composition was determined by X-ray Fluorescence and Laser Induced Breakdown Spectroscopy. Silver release was evaluated by Inductively Coupled Plasma Mass Spectrometry analysis. The gene expression levels of the Quorum Sensing Las and Rhl system were evaluated by the ΔΔCt method. The Log bacterial density (Log CFU/cm2) on TiAl6V4 was 4.41 ± 0.76 and 4.63 ± 1.01 on TiAl6V4-AgNPs compared to 2.57 ± 0.70 on CoCr and 2.73 ± 0.61 on CoCr-AgNPs (P < 0.0001, A.N.O.V.A.- one way test). The silver release was found to be equal to 17.8 ± 0.2 μg/L after the batch phase and 1.3 ± 0.1 μg/L during continuous flow. The rhlR gene resulted in a 2.70-fold increased expression in biofilm growth on the silver nanoparticles (AgNPs) coating. In conclusion, CoCr showed a greater ability to reduce microbial adhesion, independently of the AgNPs coating. The silver release resulted in promoting the up-regulation of the Rhl system. Further investigation should be conducted to optimize the effectiveness of the coating

Le fratture diafisarie delle ossa lunghe. Correzione delle deformità post-traumatiche

ABSTRACT – DIAPHYSEAL FRACTURES OF THE LONG BONES. CORRECTION OF POST-TRAUMATIC DEFORMITIES Long bone deformities as a result of trauma may lead to complications such as chronic pain, abnormal functional loading, cosmetic abnormality, joint arthritis and, if located at the lower limbs, difficult walking. The introduction of the typical circular external fixation played a prominent role in improving the management of these deformities, and second-generation circular devices (hexapod systems connected to computer planning software), which allow for simultaneous correction of all kinds of deformities in adults and children, further improved versatility, patient tolerability and nursing