Preparation Of Au/DOX-Lip And The Effect Of Theanine Liposomes On Its Antitumor Effect

As a nano carrier,liposomes can carry various drugs to achieve slow-release,targeting and increasing the solubility.The combination of drug loaded liposomes and photosensitive materials can further achieve chemo-photothermal therapy.In the development of some functional food,liposomes can be used to encapsulate functional factors to improve stability and bioavailability.However,the preparation of liposomes is not in line with the requirements of food regulations.It is an urgent problem to introduce liposome technology into the field of food.This paper studied on gold nanoparticles/doxorubicin nano liposome(Au/DOX-Lip)preparation and antitumor property,as well as explored preparation process of theanine-Lip complying with the food regulations,and then proved that the promotion effect of theanine-Lip on the antitumor of Au/DOX-Lip.In this study,we first designed and optimized conditions to synthesize gold nanoparticles in liposomes by self assemble,it had near infrared absorption and photothermal conversion characteristics.Au/DOX-Lip is uniformly spherical under the transmission electron microscope(TEM)and contains irregular gold nanoparticles with a particle size of about 100nm.Energy Dispersive Spectrometer(EDS)shows the existence of gold and oxygen elements.It further proves that liposomes successfully encapsulated gold nanoparticles.The average particle size was about 180nm,and encapsulate efficiency was 87.50%.The UV-vis spectrum shows that there is a peak at 720nm,indicating that it has near infrared absorption and has the potential of photothermal treatment.Under the near infrared light(NIR)irradiation(808nm,2W/cm~2),the Au/DOX-Lip solution(0.3mL)in 10min went up from 23 to 66.2°C,showing the superior photothermal characteristics of Au/DOX-Lip.In addition,the DOX release of Au/DOX-Lip is affected by pH.The drug release rate in pH 7.4 PBS is lower than that of PBS with pH of 5,which is contributed to the targeted release of DOX at tumor site.At the same time,the release of DOX can be promoted by NIR light irradiation after exposure to NIR.In vitro cell uptake experiments showed that the irradiation of NIR can promote the uptake of Au/DOX-Lip by cells.Those results could be explained that the heat of phototransformation enhanced the molecular motion of membrane and promotes the membrane fluidity.Cell experiments confirmed that Au/DOX-Lip after NIR irradiation(Au/DOX-Lip+Laser group)had good antitumor effect.In vivo experiments showed that Au/DOX-Lip had no obvious hepatorenal toxicity,and the tumor inhibition rate was 85.80%.The inhibition rate was higher than that of adriamycin reagents(p<0.01).It is proved that DOX loaded liposomes can significantly enhance the anti-tumor effect.In order to make the preparation of theanine liposomes to comply with the food laws,we substituted the cholesterol with the sterol.And theanine liposomes were successfully prepared by membrane hydration and calcium acetate gradient method.The average size of theanine liposomes was 169.0nm and the encapsulate efficiency was 83.6%.The cell experiments proved that theanine could enhance the antitumor effect of DOX.To further explore the promotion of theanine liposome on anti-tumor effect.Au/DOX-Lip,laser and theanine liposomes were incubated with cells simultaneously.The resullt showed that the antitumor effect of Au/DOX-Lip+Laser+theanine-Lip was much better than any others.Finally,the sleep improvementby of theanine-Lip was also studied.The results showed that compared with the control group mice,theanine and theanine-Lip were prolong the sleeping time of mice,but the time of theanine-Lip is shorter than theanine,this may be because the absorption and release of theanine-Lip need much longer time.