Functionalization of sol-gel coatings with organophosphorus compounds for prosthetic devices

Sol-gel coatings are proposed as surface treatments for titanium-based materials to promote the osseointegration of prosthetic devices with the host. As precursors of sol-gel synthesis, two silanes were selected: 3-methacryloxypropyltrimethoxy silane and 2 tetramethyl orthosilane. Sol-gel synthesis was functionalized with the addition of two different organophosphorus compounds, namely, tris(trimethylsilyl) phosphite and tris(trimethylsilyl) phosphate. Depending on the organophosphorus compound, phosphorus was incorporated into the sol-gel network by different mechanisms: organophosphate was incorporated following a hydrolysis/polycondensation reaction with the precursors of synthesis (two organopolysiloxanes), whereas organophosphite was introduced into the network through transformation of trivalent phosphorus to pentavalent phosphorus following a Michaelis-Arbuzov reaction and subsequent reaction of hydrolysis/polycondensation. When compared to the control coating, which has good adhesion coating-substrate, only the addition of the organophosphite ensured good adhesion without altering synthesis. The resulting coating modified with organophosphite was subjected to cellular study and the concentration of this compound was varied to reach the highest enhancement of proliferation. It was demonstrated that by increasing the amount of organophosphite cell proliferation increased. Inspection of the surfaces of the coatings revealed that by increasing the quantity of organophosphite, adhesion to the substrate was compromised. Thus, an intermediate quantity of organophosphite was considered the most suitable for application on metallic prosthetic devices.