Preparation Of The Fe₃O₄/SiO₂Composite Nano-Beads And DNA Purification

Purpose:This paper will explore the preparation conditions for magnetic bionanoparticles complexes to build a separation system centered on magnetic separation techniques. And further focuses on its application performance in biology by testing with multiple DNA extraction methods, specifically on the practicability of fragment screening for complex PCR products after purification.There are two parts to this research:1. Preparation for Fe3O4/SiO2magnetic bionanoparticles complexes:This article practices the universally adopted co-precipitation method by first obtaining superparamagnetic Fe3O4hydromagnetic fluid and then producing the Fe3O4/SiO2magnetic bionanoparticles complexes through sol-gel process. Through manipulating the number of times for the SiO2coating process, two magnetic bionanoparticles are generated. Quality assessment is based on each magnetic bionanoparticle’s DNA absorption and recovery capacity as its biology-application index value.2. Research into Fe3O4/SiO2magnetic bionanoparticles complexes for DNA purification purposes:This section delves into extraction and purification of DNA samples from multiple organisms through the use of Fe3O4/SiO2magnetic bionanoparticles complexes, including extraction and purification of plasmid DNA, purification of PCR product, and performance in DNA absorption and elution of the magnetic bionanoparticles. It also focuses on the adjustments to the system of "magnetic bionanoparticles+buffer solution" in order to attain selective recovery of DNA fragments with different sizes.Results:1. This study has successfully produced Fe3O4/SiO2magnetic bionanoparticles complexes and biology-application index value indicates the plasmid DNA produced by this magnetic bionanoparticle is close to, and even surpass commercial test kits in all areas in quality, quantity and purification index. It is also is in full compliance with the research requirements for future microbiology research applications.2. In the process of using the Fe3O4/SiO2magnetic bionanoparticles complexes to recover purified PCR products and by researching into the system of "magnetic bionanoparticles+buffer solution", this study has also successfully establish the technique system in selective recovery of DNA fragments of different lengths:Using "volume of magnetic bionanoparticles solution:volume of DNA samples" ratio as its parameter, number between0.4-0.5can remove DNA fragments of400bp and below effectively; parameter number0.6can remove DNA fragments of200bp and below effectively; number between0.7-1.2can remove DNA fragments of100bp and below; number between1.3-1.8can remove DNA fragments below100bp.