Dear SilicaFig,
Thank you for your message. Frankly speaking, I did not consider the possibility that TEOS might not be accessible to some, but you are right.
We did not try to use sodium silicates for coating, but it seems it is not too difficult to do, so we might give it a try sometime. If you are planning to try this before we do, it would be great if you could share your experience here for others.
Best regards and thank you,
T.