Study On Key Parameters Of Transdermal Delivery Of Hepatitis B Vaccine Mediated By High Intensity Focused Ultrasound

In recent years,with the gradual disclosure of the important role of skin in the protection of human immunity,how to deliver macromolecular antigens into the skin and induce immune activation has become a hot topic in the field of vaccination.In this paper,a new method of percutaneous immunity based on high intensity focused ultrasound(HIFU)is proposed.Compared with the traditional method for percutaneous injection of the vaccine,the method is expected to realize automatic immunity by using the echo positioning and the acoustic beam energy.In this paper,the platform of ultrasound percutaneous immunity is built.The platform can accurately locate the skin samples by ultrasonic echo detection,and then induce micropores on the skin surface by HIFU.Through India ink staining calibration of micropores and fluorescein indication of total in-vivo delivery,we can study the generation rule of ultrasonic skin micropore induction.By using the optimal ultrasonic excitation parameters,we further studied hepatitis B surface antigen in vivo,and verified the safety and effectiveness of this method.The findings of this paper are as follows:(1)in the ultrasonic frequency parameters setting,3.3 MHz frequency is higher than 1.1 MHz frequency,which can induce skin micropores with smaller area and more regular shape;(2)in the negative sound pressure parameters setting,the threshold negative sound pressure at the 1.1 MHz frequency parameter is 20.88 MPa,and the threshold negative sound pressure at the 3.3 MHz frequency parameter is 10.43 MPa;(3)there were individual differences in mice,which showed that the skin of different parts of mice and the skin of different hair follicles density of mice had different tolerance to ultrasound.It was found that the abdominal skin and the skin with high density of hair follicles were more likely to be damaged and the degree of injury was greater.(4)We found that under the same negative pressure parameters,with the different output waveforms of the signal,the degree and probability of skin damage are different,we found that: shorter ultrasound pulses(75 cycles)with higher pulse repetition frequency(4 kHz)resulted in largerand deeper skin delivery regions with higher success rate.(5)it was verified that using ultrasound,adding chemical adjuvants and increasing the number of ultrasonic excitation sites could promote the penetration of the vaccine,and there is synergy between them.It is preliminarily believed that the regulation of skin injury degree can be realized by setting the parameters of ultrasound,mainly the area and depth of injury;Through transdermal delivery of hepatitis B vaccine in vivo,the feasibility of focused ultrasound in delivery of hepatitis B vaccine was verified,and the addition of adjuvants could promote the penetration of the vaccine.This method has the feasibility and prospect of application in percutaneous automatic immunization.