The single-layer porous silicon is prepared by electrochemistry etching method,which is used as an immunosensor for determining recombinant mouse zona pellucida 3 fusion protein(r-mZP3) by Raman spectroscopy analysis at room temperature.The molecule binding increases the effective optical thickness(EOT),and thus the Raman spectrum intensity decreases.The concentration and variation of Raman intensity show a good linear quantitative relation.The excellent sensing performance could open the way to a new family of optical sensors for biological standardization.
The enhanced sensitivity of a guided mode biosensor is analyzed by employing double-layered porous silicon grating structures. The grating-coupled waveguide structure consists of two porous silicon grating layers with different refractive indices. simulations are carried out by changing the refractive index, which is due to the binding of biological molecules on the porous silicon pore can increase the refractive index of porous silicon. The numerical results show that this novel guided mode biosensor with a double-layered grating can provide not only a very high sensitivity but also a better reflectivity characteristic.
