Preparation and application of DNA-magnetic nanoparticle complexes

• Main Authors: Ya-Ling Liao, 廖雅苓
• Other Authors: Wen-Chien Lee
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/70139709902846519358

碩士 === 國立中正大學 === 化學工程研究所 === 89 === Nanoparticles and DNA conjugation have been used widely in drug delivery, gene therapy and gene transfection. In this study, magnetic nanoparticles (ferro fluids ) were prepared by the method of alkaline precipitation at pH 10 and 60℃. The average diameter of prepared magnetic nanoparticles was determined by photon correlation spectroscopy (PCS) measurement to be in the range of 10~100 nm. The saturated magnetization of particles was measured by SQUID at 25℃ to be 59.7 emu/g. The surface of magnetic nanoparticles was modified by coating using 0.5 g/L polyethyleneimine (PEI). Amino groups on the resultant particles were used for complexing with negnative charged DNA molecules.The zeta potential of nanoparticles changed from 0 to 13.9 mV by PEI coating. The particles size of PEI coated particles was 65.2 nm. The plasmid DNA attached to the PEI-coated nanoparticles could be transformed into E. coli by a high magnetic field. The results indicate that the delivery of DNA to bacterial cells was successful. The transformation efficiency was 149 cfu/μg DNA. The magnetic field influenced significantly on transformation efficiency. The transformation efficiency was 23.7 cfu/μg DNA when the mass ratio of nanoparticle to DNA was 3.87 and the magnetic field was at the saturated magnetization of the nanoparticles (2.15T). A too high or too low value of magnetic field would cause the deadth of cells. Increasing the mass ratio nanoparticles and DNA, the transformation efficiency increased. When the mass ratio increased from 2.4 to 24000, the transformation efficiency increased from 4.0 cfu/μg to 31500 cfu/μg. The results of this work show that nanoparticles could well assist DNA into bacterial cells. In summary, using magnetic nanoparticles as the DNA carrier are highly potential and worthy to be further studied.