The Study Of Synthesis And Properties Of BBB-permeable And Cell-penetrating Peptide Modified Thermosensitive Gel Carriers

ObjectiveGlioblastoma multiforme(GBM),the most frequent and aggressive form of malignant primary brain tumors,is universally fatal due to its highly diffuse infiltration and striking angiogenic potential surrounding the brain.Despite surgical and medical advances,the prognosis for most brain cancer patients remains dismal and the median survival rarely exceeds 16 months.MethodsWith the remarkable advancements in nanotechnology,variety of inorganic/organic/natural nanomaterials with surface modification of BBB-targeting ligands and/or cell penetrating peptides(CPP)have been created to cross the BBB for highly accurate theranostics of brain tumours.The so-called BBB-crossing nanotechnology is expected to make a revolutionary impact on conventional brain cancer management.ResultsBased on this,the nano gel PEI-PNAPAM was carried to adjust the particle size with its thermosensitive effect,for decreasing the particle size to ensure that the nano gel can pass through the BBB membrane.In addition,the surface of nano gel was modified with cell penetrating peptide(CPP)to enhance the ability of the nano gel to penetrate the BBB.The morphology and particle size were characterized with scanning electron microscopy and dynamic and static laser scattering.The results showed that nano gel with a spherical shape and uniform size was successfully synthesized with a particle size of 600 nm approximately.The temperature-sensitivity characteristics of the Nano gel were studied using a dynamic and static laser scattering instrument.It was found that the particle size of the Nanogel gradually decreased with increasing temperature,and the particle size was 300 nm at a tumor-like temperature of 42 °C.The Nano gel can completely condense DNA at N/P of 30.Compared with the PEI,the particle size distribution and Zeta potential of nano gel with DNA at different N/P,different temperatures,were tested respectively.The results show that the complex formed by the nano gel and DNA has temperature-sensitive properties,and with the increase of N/P,the particle size gradually decreases,and Zeta increases first and then decreases.When N/P is 30,stable nanoparticles are formed.The reporter gene of luciferase was carried to verify the transfection of the nano gel,and the results showed that compared with PEI,the CPP-modified thermosensitive nano gel showed better transfection efficiency in the absence of serum,which was equivalent to PEI.In the presence of serum,the CPP-modified temperature-sensitive nano gel showed a better transfection efficiency that was twice that of PEI.Finally,we constructed a BBB model according to the methods reported in the literature.Due to the temperature-sensitive properties of the carrier,the carrier can adjust the particle size when passing through the BBB,and under the action of the CPP,it can enhance the penetrating ability of the nano-delivery system to BBB,but pure doxorubicin partially blocked.At the same time,the complex system that passes through the BBB membrane can kill the glioma cells.ConclusionsThis paper provides a strategy for the design and synthesis of an effective targeted delivery system for glioma cells.In the future,we can use this system to carry si RNA and DOX to achieve the purpose of synergistically inhibiting tumor growth.