Limits...
DNA Optical Detection Based on Porous Silicon Technology: from Biosensors to Biochips

View Article: PubMed Central

ABSTRACT

A photochemical functionalization process which passivates the porous silicon surface of optical biosensors has been optimized as a function of the thickness and the porosity of the devices. The surface modification has been characterized by contact angle measurements. Fluorescence measurements have been used to investigate the stability of the DNA single strands bound to the nanostructured material. A dose-response curve for an optical label-free biosensor in the 6-80 mM range has been realized.

No MeSH data available.


Characterisation of the PSi surface by contact angles measurements. A) The PSi as etched shows a clearly hydrophobic behaviour. B) After the passivation process the PSi surface is hydrophilic thus allowing the penetration of biological solution.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3756702&req=5

f2-sensors-07-00214: Characterisation of the PSi surface by contact angles measurements. A) The PSi as etched shows a clearly hydrophobic behaviour. B) After the passivation process the PSi surface is hydrophilic thus allowing the penetration of biological solution.

Mentions: The surface passivation is also well evident by contact angle measurements: the hydrogenated PSi surface is highly hydrophobic, due to the presence of the Si-H bonds, so that a drop of deionised water exploits a high surface tension which prevents its diffusion in the pores. This behaviour is well depicted in Figure 2A: the contact angle is 137±1 degree, averaging the left and right values of three different drops having the same volumes, and the estimated surface tension is 179 mN/m. After the photoreaction with the UANHS, the Si-H bonds are replaced by the Si-C bonds and the PSi surface shows a hydrophilic behaviour, as shown in Figure 2B: the drop spreads on the surface and the contact angle drastically decreases to 43±3 degree and also the surface tension is lowered to 67 mN/m. In this condition, an aqueous solution can be infiltrated in the nanostructured layer.


DNA Optical Detection Based on Porous Silicon Technology: from Biosensors to Biochips
Characterisation of the PSi surface by contact angles measurements. A) The PSi as etched shows a clearly hydrophobic behaviour. B) After the passivation process the PSi surface is hydrophilic thus allowing the penetration of biological solution.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756702&req=5

f2-sensors-07-00214: Characterisation of the PSi surface by contact angles measurements. A) The PSi as etched shows a clearly hydrophobic behaviour. B) After the passivation process the PSi surface is hydrophilic thus allowing the penetration of biological solution.
Mentions: The surface passivation is also well evident by contact angle measurements: the hydrogenated PSi surface is highly hydrophobic, due to the presence of the Si-H bonds, so that a drop of deionised water exploits a high surface tension which prevents its diffusion in the pores. This behaviour is well depicted in Figure 2A: the contact angle is 137±1 degree, averaging the left and right values of three different drops having the same volumes, and the estimated surface tension is 179 mN/m. After the photoreaction with the UANHS, the Si-H bonds are replaced by the Si-C bonds and the PSi surface shows a hydrophilic behaviour, as shown in Figure 2B: the drop spreads on the surface and the contact angle drastically decreases to 43±3 degree and also the surface tension is lowered to 67 mN/m. In this condition, an aqueous solution can be infiltrated in the nanostructured layer.

View Article: PubMed Central

ABSTRACT

A photochemical functionalization process which passivates the porous silicon surface of optical biosensors has been optimized as a function of the thickness and the porosity of the devices. The surface modification has been characterized by contact angle measurements. Fluorescence measurements have been used to investigate the stability of the DNA single strands bound to the nanostructured material. A dose-response curve for an optical label-free biosensor in the 6-80 mM range has been realized.

No MeSH data available.