Green Process Of Preparation Of Polyethyleneimine Derivatives Research In Cell Scaffold And Mediated Gene Transfection

Polyethyleneimine (PEI) as one of the most typical cationic polymer, has been widely used intissue engineering scaffolds as well as the carrier of gene transfection, but its significantcytotoxicity and poor biocompatibility severely limit its applications. The chemical method for thePEI molecular modification is effective to reduce the cytotoxicity and can improve bloodcompatibility. Electrostatic spinning is an effective preparation of nano or micro fiber productiontechnology level. The nanometer fiber made by Electrostatic spinning has a great specific surfacearea, and can very well simulate the natural extracellular matrix. nanometer fiber can also providea good environment for cell adhesion, proliferation and physiological functions. This papercombined with the advantages of the good biocompatibility of zwitterionic compounds, designand synthesis the zwitterionic compounds PEI derivatives. This paper focuses on the use of highvoltage electrostatic spinning technique to prepare modified material and the low toxicity of theperformance of the nano composite fiber and cell toxicity characterization of polyvinyl alcohol(PVA); And the interaction of modified PEI (PEI-C) as gene carrier in aqueous solution withPlasmid deoxyribonucleic acid (pDNA), the formation of the nano composites, interactionsbetween the carrier biocompatibility, cytotoxicity and gene complexes in vitro transfectionperformance, etc. The research content of this paper is mainly divided into the following severalaspects:In the first section, Using of the concept of green chemistry and based on the rich aminopolymers on carbon dioxide having a strong adsorption, the paper combines the advantages of thegood biocompatibility of zwitterionic compounds with carbon dioxide to modify hyperbranchedPEI25KDa to prepare polyethylene imine derivatives (PEI-C). The paper concludes its nuclearmagnetic analysis, element content detection and Fourier transform infrared spectrometer (FT-IR),characterization of its structure and the change of element content before and after modification.Based on the influence of CO2uptake of PEI in different factors such as time, concentration ofpreparation PEI-C, It is found that the PEI concentration controls between20%~40%; whencarbon dioxide bubbles after0.5h, oxygen content in the PEI has reached27%. Compared withthe undecorated PEI25k, MTT cell toxicity experiments show that cells relative viability of PEI-C remains at around80%; while the cytotoxicity of PEI is enhanced with the increase ofconcentration, and cells relative viability reduces from80%to less than30%. It indicates that thecytotoxicity of PEI-C is significantly reduced.In the second section, we fabricated PEI-C/PVA nanofibers matrixes by electrospinningPEI-C and PVA mixture solution. The influence of the processing parameters such as flow rate,collection distance, voltage, and the polymer concentration on the morphology of the nanofiberswas systematically investigated.Further, fiber membrane crosslinking with glutaraldehyde steamto get water stable nanometer fiber membrane. By using scanning electron microscope (SEM) andFTIR to character its fiber membrane crosslinked before and after the change of the chemical andphysical properties. SEM observation showed that schwann cells in the PEI-C/PVA compositefiber membrane surface of the extracellular matrix distribution is more dense and cell morphologysignificantly is better compared to the extracellular matrix unmodified PEI/PVA composite fibermembrane. When the mass ratio is35:65, MTT cell toxicity experiment further shows that thecells OD value of PEI-C/PVA fiber scaffolds is0.47, being equalled to2times of PEI/PVA fiberscaffolds. The modified composite fiber scaffolds cytotoxicity is decreased obviously comparedwith the unmodified PEI/PVAcomposite fiber scaffolds.The third section describes the material of modified PEI-C is used to study of genetransfection vectors using gel electrophoresis apparatus to investigate the combination of carrierand pDNA ability; The paper studys the size and electric potential of the compounds formed bycarrier and pDNA.Protein adsorption experiment showed that carbon dioxide modified PEI carrierimproved ability to resist protein adsorption; Deoxyribonuclease I (DNase I) protection andrelease experiments show that the PEI-C carrier material has ability to protect pDNA fromnuclease degradation in cells, and it can release the pDNA. MTT cell toxicity experiments showthat the PEI-C carrier gene complexes (pDNA/PEI-C) cytotoxicity significantly reduced comparedwith the undecorated PEI carrier gene complexes (pDNA/PEI); The vitro transfection experimentsconfirmed that the PEI-C can effectively mediated gene transfection. Using Hepa1-6cells andQBC939cells for the model, with the serum, the transfection rate of PEI-C being a transfectioncarrier is above33%in Hepa1-6cells and QBC939cells even reaching higher than thetransfection efficiency when PEI25k being carrier, and with the increase of N/P, the transfectionefficiency grows from about33%to about62%; Without the serum, the cells transfectionefficiency of PEI-C as carrier in the two kinds of cancer cells also remain above20%, being about2.5times higher transfection efficiency than25kda PEI as a carrier, and laser confocal imagesis also identical. the results show that the PEI-C can effectively complete gene transfection.