The Intracellular Uptake Study On The Magnetic Mesoporous Silica Nanoparticles With Different Shapes And Its Mechanism

The intracellular uptake of drug-carrying nanoparticles is the precondition for thetargeted drug release. The shape of nanoparticle is one of the important factorseffecting intracellular uptake, which affects the rates, contents and pathways forcellular uptake. As a consequence, investigation of the cellular uptake and itsmechanism in the nanopaticles with different shapes was very important for screeningan ideal nanocarrier. Among various nanomaterials, magenetic mesoporous silicananoparticles (M-MSN) were extensively applied as chemotherapy delivery carriers,expecilly core-shell mesoporous silica nanoparticles. Our group fabricated a novelJanus magneticmesoporous silica nanoparticles with several good characters, such astumor targeting, good biocompatibility, low toxicity and the controlled release drug,and it is a promising chemotherapy or functional gene vector for cancer therapy.However, the exact effect of nanoparticle shape on in vitro behavior remained poorlyunderstood. This information is of considerable important in understanding how toimprove nanomaterial safety and uptake. Herein, we synthesis three different shapesM-MSNs, they are core-shell M-MSN (M-MSNP0), Janus short rod M-MSN(M-MSNP1) and Janus long rod M-MSN (M-MSNP2).The project focuses on thestudy of the cellular uptake and its mechanism in the three M-MSNs with differentshapes, which might provide the theory base for screening the better nanocarriers inthe treatment of cancer.Research contentsWe synthesis three different shapes M-MSNs, they are core-shell M-MSN(M-MSNP0), Janus short rod M-MSN (M-MSNP2) and Janus long rod M-MSN(M-MSNP2).The characteristics of the nanoparticles and the study of the cellular uptake and its mechanism in the three M-MSNs with different shapes were carriedout.Methods and Results1. The three different shapes M-MSNs were successfully synthesized and qualitycontrol system was formed. The average size of core-shell M-MSNP0is about200nm.The average minor axis of Janus short rod M-MSNP1and long rod M-MSNP2isabout100nm, and the ratios of major axis to minor axis(aspect ratios) are1-1.2and3.5-4.0respectively.2. The three different shapes M-MSNs were characterized with instruments and itis showed that the nanoparticles have good magnetic capacity and mesoporousstructure.3. SRB assay showed that the three M-MSNs do not influence on the cell viabilityof human hepatocarcinoma HepG2, human embryo hepatic cell L02and humancervical carcinoma Hela in the concentrations from0.78μg/ml to50μg/ml, indicatingthat the M-MSNs has good biosafety.4. The cellular uptake contents and distribution image of the M-MSNs wereevaluated in3h and24h by laser scanning confocal fluorescence microscope, flowcytometry and Prussian blue staining. We found that the uptake contents of long rodM-MSNP2is more than short rod M-MSNP1, and the core-shell M-MSNP0haslowest uptake contents in HepG2cell.5. Endocytosis inhibitors were utilized to detect uptake pathways which theM-MSNs are dependent on. The results showed that the endocytosis contentsdecreased by co-culture with Sodium azide, low temperature(4℃)andchlorpromazine，implying that ATP utilizing and clathrin-mediated endocytosis wereinvolved in all three M-MSNs. In addition, short rod M-MSNP1uptake content wasreduced when it was treated together with Nystatin, indicating that short rod enteringinto cells is partially dependent on the caveolae pathway, and the endocytosis of longrods decreased when prior to co-culture with amiloride, suggesting thatmacropinocytosis is involved in the endocytosis of M-MSNP2. All the data showedthat the M-MSNs with different shapes are related to different endocytosis pathways. ConclusionThe three different shapes M-MSNs were successfully synthesized and qualitycontrol system was formed. These nanoparticles have good magnetic capacity andmesoporous structure. SRB assay showed that the M-MSNs have good biosafety. Theendocytosis contents of long rod M-MSNP2is more than short rod M-MSNP1, andthe core-shell M-MSNP0has lowest uptake contents in cytoplasm of HepG2cell. ATPutilizing and clathrin-mediated endocytosiswere involved in all three M-MSNs andthe M-MSNs with different shapes are related to different endocytosis pathways.