Design Of A TFBG Biochemical Sensing Platform Based On Fermi Energy Level Modulation Of ZnO Nanoflowers

Tilted fiber Bragg grating(TFBG),as a new communication band fiber passive device,has the advantages of low cost,miniaturization,high sensitivity and other sensing advantages of ordinary fiber Bragg grating(FBG),but also has efficient cladding mode coupling characteristics,can flexibly excite the high-order cladding mode,the core energy efficiently coupled to the fiber surface and material interaction to form a different physical field coupling mechanism,to achieve high sensitivity to external perturbations.The high sensitivity of external perturbation perception.However,TFBG bare fiber has a weak swift field and low sensitivity to external environment detection.With the development of SPR and fiber optic sensing technology,TFBG-SPR sensors are attracting attention because of their high sensitivity and the use of gold nanoscale amplification effect,which can enhance the detection sensitivity and reduce the detection limit.Therefore,TFBG fiber optic biochemical detection technology has been widely used in various sensing fields.However,there are still some systematic problems and technical bottlenecks in the development of the sensor: first,bare fiber excitation cladding mode resonance abruptly passing field is limited,coupling efficiency is low,additional two-dimensional material sensitization is required;second,the sensing system is limited by spatially fixed sensing surface volume effect perturbation,the perceived signal is not obvious;finally,the TFBG-SPR sensor can only be excited by TM single polarization,flexibility is limited,while the sensor design process is complex and costly.Therefore,there are contradictions and bottlenecks in many aspects such as polarization dependence of coupled resonance mechanism,flexible spatial extension of the sensing system,and passive capture system.To address the above issues,this paper proposes a mechanism to combine the strong avidin biotin-avidin(BAS)system to modulate the Fermi energy level at the Zn O molecule/solid interface and design a general and efficient sensing platform for biochemical detection.For the doping of S element in Zn O synthesis,the Fermi energy level of the material itself is increased.TFBG is sensitive to the material dielectric constant perception and can effectively sense the refractive index change of Zn O,while combined with the BAS system,the liquid gating effect generated by the binding promotes the electron transfer from Zn O to biotin,which reduces the Fermi energy level of Zn O itself,and the change in transmission spectrum is used to detect the Fermi energy level of Zn O due to the absence of The Fermi energy level change of Zn O caused by the concentration of biotin was detected by the change of transmission spectra.At the same time,biotin is easily modified and can be used for the detection of more biomolecules.The advantages of this biochemical sensing platform are as follows.1.Zn O nanomaterials,with low production cost,mature process and stable detection unit;nanoflowers with large specific surface area,abundant surface functional groups and self-sensitizing ability can simplify the sensing system and reduce the modification process while obtaining higher reproducibility and stability.2.The sensing system relies on Zn O’s own Fermi energy level modulation,breaking the spatial limitation of sensing unit perception;the sensing platform does not need specific polarization state excitation,realizing the mode coupling mechanism without polarization dependence,solving the key bottleneck problem of TFBG coupling mechanism in applications.3.Using the biotin-affinity binding system as a sensing bridge,on the one hand,the biotin-affinity binding produces a liquid gating effect that can modulate the Fermi energy level on the solid surface,and on the other hand,the BAS system,as an immunolabeling bridge,is easy to combine different biomolecules to establish the relationship between the target and the Fermi energy level modulation,and has a multi-level amplification effect.In summary,the proposed biochemical sensing platform based on the Fermi energy level modulation at the molecular/non-metallic material solid interface solves the problems of inflexible fixation and complex signal amplification system of the traditional system,which makes the biochemical sensing platform have better signal amplification characteristics and biochemical detection versatility.