Mechanical compatibility of sol–gel annealing with titanium for orthopaedic prostheses

Sol–gel processing is an attractive method for large-scale surface coating due to its facile and inexpensive preparation, even with the inclusion of precision nanotopographies. These are desirable traits for metal orthopaedic prostheses where ceramic coatings are known to be osteoinductive and the effects may be amplified through nanotexturing. However there are a few concerns associated with the application of sol–gel technology to orthopaedics. Primarily, the annealing stage required to transform the sol–gel into a ceramic may compromise the physical integrity of the underlying metal. Secondly, loose particles on medical implants can be carcinogenic and cause inflammation so the coating needs to be strongly bonded to the implant. These concerns are addressed in this paper. Titanium, the dominant material for orthopaedics at present, is examined before and after sol–gel processing for changes in hardness and flexural modulus. Wear resistance, bending and pull tests are also performed to evaluate the ceramic coating. The findings suggest that sol–gel coatings will be compatible with titanium implants for an optimum temperature of 500 °C

Increased efficiency of direct nanoimprinting on planar and curved bulk titanium through surface modification

In this work the direct transfer of nanopatterns into titanium is demonstrated. The nanofeatures are imprinted at room temperature using diamond stamps in a single step. We also show that the imprint properties of the titanium surface can be altered by anodisation yielding a significant reduction in the required imprint force for pattern transfer. The anodisation process is also utilised for curved titanium surfaces where a reduced imprint force is preferable to avoid sample deformation and damage. We finally demonstrate that our process can be applied directly to titanium rods

Mehrstichproben-Rangtests bei einseitigen Alternativen zur statistischen Auswertung von Mutagenitaetsexperimenten

TIB: RN 6363 (1985,3) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Grooved surface topography alters matrix-metalloproteinase production by human fibroblasts

Extracellular matrix (ECM) remodelling is an essential physiological process in which matrix-metalloproteinases (MMPs) have a key role. Manipulating the manner in which cells produce MMPs and ECMs may enable the creation of a desired tissue type, i.e. effect repair, or the prevention of tissue invasion (e.g. metastasis). The aim of this project was to determine if culturing fibroblasts on grooved topography altered collagen deposition or MMP production. Human fibroblasts were seeded on planar or grooved polycaprolactone substrates (grooves were 12.5 µm wide with varying depths of 240 nm, 540 nm or 2300 nm). Cell behaviour and collagen production were studied using fluorescence microscopy and the spent culture medium was assessed using gel zymography to detect MMPs. Total collagen deposition was high on the 240 nm deep grooves, but decreased as the groove depth increased, i.e. as cell contact guidance decreased. There was an increase in gelatinase on the 2300 nm deep grooved topography and there was a difference in the temporal expression of MMP-3 observed on the planar surface compared to the 540 nm and 2300 nm topographies. These results show that topography can alter collagen and MMP production. A fuller understanding of these processes may permit the design of surfaces tailored to tissue regeneration e.g. tendon repair

Untersuchung zur Herstellung von galvanisierbaren Mikrostrukturen mit extremer Strukturhoehe durch Abformung mit Kunststoff im Vakuum-Reaktionsgiessverfahren

Dissertation submitted by H. VollmerSIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman