Hi all,
I am looking for the best way to evaluate the biocompatibility of a new titanium coating. Dose anyone got the knowlage how to do it?

Hi gsovak,
Can you be more specific with "check biocompatibility"?
I assume you mean you want to coat a surface with titanium and see if cells can grow either on, or in the presence of it.

Either way you can check viability of cells with stains--methylene blue and trypan blue are two that come to mind. If the cells take the dye, this means the cells are dead. Otherwise, the dye will not cross the membrane. If you have electrically exciteable cells (neurons or cardiac myocytes, for instance) you could use a voltage sensitive dye and try to stimulate them. I highly recommend Di-4-ANNEPDHQ voltage sensitive dye.

If you want to make an adhesive coating for your titanium surface for cells to anchor to, you should try the LBL ("layer-by-layer") method. You coat with sandwich of alternating layers of positively/negatively charged molecules.
I use PEI(+) and laminin(-), three layers of each. I've seen some papers that use LBL on sylgard, coating up to 8 or 16 layers, and they report excellent cell adhesion.

If you want a reference, let me know and I'll dig one up.

Finally, I've found that when I have something potentially noxious in the cell culture due to fabrication/processing that if I soak the component in saline for a week, changing solution daily, there are absolutely no problems with biocompatibility.

Good luck!

Thanks for the answer,
When I asked for biocompatibility check/assay, I meen that I would like to asses if the titanium coating on the titanium disks could be used as a coatng for implants. So I think that after doing what you said with the viability test in the cell culture I need to move to an animal. Most probably a rat. One way would be to implant it paracotaneous and to check for imflamation etc.
The question do you think of any more assays that I nead to use?
Thnks
Guy

If you have access to the equipment/facilities, you could do some confocal scanning of your tissue to check cell morphology and for scarring. That seems to be fairly standard. You can choose whether to open the animal before or after the surgery, but the cell morphology around the implant is usually tell-tale.

There seems to be a fairly lengthy list of titanium in biomed applications, so I'm going to wager that you won't have excessive problems with biocompatibility.

Finally, if you are worried about biocompatibility, you could coat your implant with a nanolayer of dextran. This works in neural cell culture, but I don't know into what tissue you are implanting.

As per Ti6Al4V it is biocompatible.
That is not the main problem/Question. The question that I am asking is regarding an enhancement to the surface ability to osteointegrate by chemical or other methods that I am trying.
So I am looking for ways to ensure that the implants are still biocompatible.

Have considered Atomic Force Microscopy to check for the presence of cytokines in cells contacting the metal? It's an affordable system of real-time immune response monitoring.
There are a number of companies producing cytokine detection tips for AFM.

K

I don't know if this string is still of interest to you, but I have always found that biocompatibility testing, as defined by regulatory agencies, is best performed at contract labs such as Toxikon or NAMSA. For a list of appropriate tests, go to:

http://www.namsa.com/pdfs/biocompat_matrix.pdf

and a nice overview can be found at:

http://www.devicelink.com/mpb/archive/97/05/001.html

Cheers