Question

Join borosilicate glass substrates containing a-SiC:H films with substrates containing

titanium films. This will be done by activating the surface of the wafers with APTMS ((3-Aminopropyl) trimethoxysilane) to subsequently bind these molecules with glutaraldehyde.

¿How can I improve biofunctionalization between APTMS ((3- Aminopropyl) trimethoxysilane) and glutaraldehyde?

Answer 1

Physical adsorption is one of the simplest technique used for the binding of biomolecules on the glass surface.

The negatively charged DNA can bind to amine modified glass surface through ionic interactions. That is why APTMS surface treatment is used to chemically couple various ligands to glass or silica surfaces. This chemical is first coupled to glass or silica through the silane which is known as silanization. But by only aminosilanization, it does not result in reproducible results due to poor detection of any analyte. Due to this disadvantage covalent modifications are done which include aldehyde modification(glutaraldehyde binding).

The enzyme or DNA or any analytes are immobilized on functionalized supports using glutaraldehyde which act as a bi-functional cross-linking agent. The linker reacts with the chemically modified glass slides. While the other end is required to immobilize enzymes. To improve the bio-functionalization of the glass slides following steps are taken:

1. The APTMS modified slides are treated with glutaraldehyde (2.5% v/v) in 0.1M PBS at room temperature for 2hours.

2.The slides are then washed and dried.

3. The analytes are spotted onto the slides and incubated in humidified chamber for 24 hours.

4. Blocking of unreacted aldehyde functional group by treatment with sodium borohydride. This ensure the bio functionality of the glass slides.