适配体功能化二氧化钛基复合光催化剂选择性降解黄曲霉毒素B_(1)作用研究

Study on selective photocatalysts degradation of aflatoxin B_(1) by aptamer-functionalized TiO_(2)-based composite

为了探究可高效、选择性降解食品中黄曲霉毒素B_(1)(AFB_(1))的方法,采用核酸适配体(aptamer)对磁性氧化石墨烯复合二氧化钛(MGO/TiO_(2))光催化剂材料进行选择性修饰,合成适配体功能化MGO/TiO_(2)光催化复合材料(MGO/TiO_(2)-aptamer),并考察了该光催化剂对AFB_(1)的降解效果及其特异性,探究不同因素对MGO/TiO_(2)-aptamer降解AFB_(1)的影响。结果表明:TiO_(2)与Fe_(3)O_(4)颗粒相对均匀地附着在MGO片层表面,且傅里叶红外光谱显示适配体的骨架、碱基以及CO—NH键特征峰,通过透射电镜发现Ti、Fe元素以及aptamer特有的N、P元素,表明适配体功能化MGO/TiO_(2)材料成功合成;与未修饰的MGO/TiO_(2)材料相比,MGO/TiO_(2)-aptamer对低质量浓度AFB_(1)和混合毒素中AFB_(1)的降解率显著提高,验证了其对低质量浓度毒素的降解增强效果以及选择性降解性能。在优化条件下,当MGO/TiO_(2)-aptamer添加量为6 mg,在pH 3的环境中使用紫外可见光照射120 min后,AFB_(1)降解率可达98.3%,且AFB_(1)的光催化降解遵循Langmuir-Hinshelwood准一级动力学模型。

Aflatoxin B_(1)(AFB_(1))is highly carcinogenic,teratogenic and mutagenic,posing a serious threat to the life safety of humans and animals.In order to explore an effective method for efficient and selective degradation of aflatoxin B_(1)(AFB_(1))in food,the aptamer functionalized modification of magnetic graphene oxide composite titanium dioxide(MGO/TiO_(2))photocatalytic composite(MGO/TiO_(2)-aptamer)was synthesized by aptamer selective modification of MGO/TiO_(2)photocatalyst,and the variation of the degradation effect of MGO/TiO_(2)-aptamer on AFB_(1)at low concentrations and in mixed systems was investigated.The effects of different factors(initial concentration of aptamer,material addition,pH value and light exposure time)on the photocatalytic degradation of AFB_(1)by MGO/TiO_(2)-aptamer were investigated.The kinetic behaviour of MGO/TiO_(2)-aptamer photocatalytic degradation of AFB_(1)at different concentrations was simulated.The results showed that the TiO_(2)and Fe_(3)O_(4)particles were relatively uniformly attached to the surface of MGO sheets,the characteristic peaks of the aptamer′s skeleton,base and CO-NH bonds were evident in the FTIR spectra,Ti and Fe elements as well as the specific N and P elements of the aptamer were found in the TEM diffraction spectra.The specific targeting degradation performance of MGO/TiO_(2)-aptamer on AFB_(1)and the enhanced degradation effect on low concentration of AFB_(1)were successfully verified.In addition,compared with the unmodified MGO/TiO_(2)material,the degradation rate of MGO/TiO_(2)-aptamer in low concentration AFB_(1)or mixed toxins was significantly improved,which verified its degradation enhancement effect and selective degradation performance for low concentration toxins.When the optimized conditions were the MGO/TiO_(2)-aptamer addition of 6 mg and UV-visible light irradiation for 120 min at pH 3,the degradation rate of AFB_(1)could reach 98.3%and the photocatalytic degradation of AFB_(1)followed the first-order kinetic Langmuir-Hinshelwood equation.This study provides a theoretical and data basis for the photocatalytic degradation of AFB_(1)by MGO/TiO_(2)-aptamer and broadens the application of photocatalytic technology in toxin degradation.