Fabrication and modification of fiber optic probe

Fabrication and modification of fiber optic probe

Remove about 6.5 cm of the coating layer from an 11 cm long quartz optical fiber, and then place it in 30% HF for etching for a suitable time to obtain
a combined probe with the required cone angle (defined as the ratio of the diameter of the core after etching to the diameter of the core without etching, i.e. d2/d, see Figure 1). The length of the cone part is about 0.5 cm. Prepare a pira ha solution (concentrated H2SO4:H2=3:1) and immerse the probe in it for 30 min; then wash it in an ultrasonic cleaner and thoroughly clean it with ultrapure water until the pH value of the cleaning solution is neutral. Finally, blow it dry with nitrogen at room temperature and store it in a vacuum drying oven for later use. For immunoassay, antibodies or antigens must be fixed to the probe surface.

According to the method in the literature, the probe was first silanized, and the clean probe was placed in a 2% MTS toluene solution for 2 hours. It was washed with a toluene solution for 3 times, and then placed in a 0.02 mol/L GMBS ethanol solution. After reacting for 1 hour, it was rinsed with ethanol 3 times and then rinsed with PBS. Finally, the silanized probe was placed in 0.05 L rat IgG for 2 hours, rinsed with PBS, and stored in a 4°C refrigerator for later use.

Preparation of fluorescent dye solution
Accurately weigh 0.5 mg of Cy5.5 dye, dissolve it in 50A LD MSO, prepare 10g/LC Cy5.5 solution, and then use PBS buffer to prepare 10 x 10-7 molVL stock solution. During the experiment, dilute the stock solution as required to prepare Cy5.5 solutions of different concentrations.