Study On Adsorption And Release Of Mesoporous Silica Nanoparticles For Gene

Gene therapy technology as new biomedical technologies, is to rescue mutantphenotypes by providing deficient cells with a normally functioning or healing gene. Ithas been widely used in the clinical treatment of a variety of genetic diseases andmalignant tumor. The exploiture of good carrier for gene transfer is the foundation andthe key of gene therapy. At the same time, the study of carrier is bottleneck that restrictthe development of gene therapy. As a new materials, Mesoporous silicas nanoparticles(MSN) are widely researched in novel drug carriers and bioactive macromoleculedelivery applications. Especially MSN carrier have attracted a lot of virtues, as they arenontoxic, biocompatible, biodegradable, also is a good carrier for gene therapy.The primary objective of this research is to examine the feasibility of mesoporoussilica nanoparticles SBA-15 with pore size 4~7 nm and MCM-41 with pore size 2~3nm as a gene delivery nanoparticle systems by characterization gene adsorption andrelease of the material. In this study, SBA-15 and MCM-41 were synthesized by routinemethods. Then, the surface of the SBA-15 and MCM-41 were respectively modified byN-(β-aminoethyl)-γ-aminopropyl triethoxysilane (APTS) with a amino-fnctional group.The XRD, FTIR, TEM and BET characteristics showed that SBA-15 and MCM-41 hasclear mesoporous structure. The 3D structure of amino-functionalzation MSN was notviolated. MSN mostly were ball-shaped and elliptical, with size ~150nm.This paper mainly reports adsorption and release of amino-functionalzationSBA-15 and amino-functionalzation MCM-41 for nucleic acid with different molecularweight (DMW). The XRD and FTIR data showed that amino-functionalized MSNforcefully interacted with DNA. The TEM inmage showed amino-functionalized MSNwith DNA retained good mesoporous structure. A results of BET indicated that specificsurface area decreased after supporting DNA. The Characteristic pattern in agarose gelelectrophoresis showed amino-functionalized MCM-41 can protect DNA with 30bp and100bp from DNaseⅠdegradation, but can not protect DNA with 2.7kb. Theamino-functionalized SBA-15 can not protect DNA with 2.7kb, 100bp and 30bp fromDNaseⅠdegradation.The adsorption and release process of amino-functionalized MSN for Herringsperm DNA is investigated. The experimental results demonstrated that adsorption kinetics data for DNA adsorption of amino-functionalized MSN from aqueous solutionswere in good agreement with theⅡkinetic process, but adsorption kinetics ofamino-functionalized MSN for DNA was simulated byⅠkinetic process only in itsinfancy. The adsorption isotherms of amino-functionalized MSN for DNA could besimulated well by Langmuir equation and Freundlich equation, and the correlationcoefficients were above 0.96. The most adsorbable capacity of amino-functionalizedSBA-15 and amino-functionalized MCM-41 for DNA were 60μg/mg and 70μg/mg,respectively. But the adsorbed amount of bare MSN for DNA was found to benegligible.In the experiment release of amino-functionalized MSN for DNA at different pHvalues and ionic strength and in phosphate buffered saline (PBS) or simulated bodyfluid (SBF) were investigated. The experimental results indicated that the release rate ofamino-functionalized MSN for DNA in PBS or SBF were only 2.0%~2.5%, but therelease rate of amino-functionalized MSN for DNAwere 50%~70%.In conclusion, The amino-functionalized MSN is non-toxic, with high geneadsorbance. It can effectively control the release of the gene, and can be taken into cellby endocytosis. It helps to protect the gene transfection through the combination ofMSN and gene. It not only makes the gene high expression in the cells, but avoids theimmunogenicity of the virus vector, as well as potential tumorigenic drawbacks. It couldbe concluded that the MSN are a potential, superior, good gene transfer carrier.