Abstract
To further improve the sensitivity of porous silicon-assembled microcavity biosensors, the detection of porous silicon assembled microcavity by angle spectrum method is also researched. This contribution uses CdSe/ZnS quantum dot-labelled probe DNA to amplify the refractive index and detect it by the angle spectrum method. The first layer is a microcavity layer, and the next is porous silicon with a Bragg structure. After functionalization, different concentrations of target DNA were coupled to construct quantum dot-labelled probe DNA to bind specifically to the target DNA. With the Bragg device based on quartz glass forming an assembled microcavity structure, using a He-Ne laser as the detection light and collimation beam, the angle spectrum method is used to detect different concentrations of target DNA before and after biological reaction with quantum dot-labelled probe DNA and reflect the angle of minimum light intensity. The experimental results show that with increasing target DNA concentration, probe DNA concentration and angle, the detection limit is 13.25 pM. The angle-spectrum method has been successfully used to detect the assembled porous silicon microcavity. The angle-spectrum method has the advantages of spectrometer free and low cost.
Highlights
P OROUS silicon (PSi) has a large surface area, favourable biocompatibility, and adsorption and is widely used in biosensors
The advantages of this paper are as follows: 1) Using the high refractive index of Quantum dots (QDs), the probe molecule is amplified to improve the sensitivity of the biosensor; 2) Due to the limited detection methods that can be used to assemble the microcavity, we studied the angle spectrum method for its detection, using a detector to receive the reflected light, calculate the change of the angle before and after the biological reaction, and get a lower detection limit
Biological detection is performed, in which the angle of incidence is adjusted to θ1, the light intensity is adjusted, and the lowest layer of the PSi microcavity in the biological reaction is added after the refractive index is increased again
Summary
P OROUS silicon (PSi) has a large surface area, favourable biocompatibility, and adsorption and is widely used in biosensors. The advantages of this paper are as follows: 1) Using the high refractive index of QDs, the probe molecule is amplified to improve the sensitivity of the biosensor; 2) Due to the limited detection methods that can be used to assemble the microcavity, we studied the angle spectrum method for its detection, using a detector to receive the reflected light, calculate the change of the angle before and after the biological reaction, and get a lower detection limit. The advantages of this method are spectrometer free and low cost
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