PSMA@Ag复合微球的制备及其在MALDI-MS分析小分子化合物中的应用研究

基质辅助激光解吸电离质谱(MALDI-MS)作为一种有力的分析手段,在生物分子分析中有着广泛的应用,但很难应用于分子量小于500的待测物的分析。该文利用聚多巴胺修饰还原法制备了核壳结构的聚苯乙烯-马来酸酐共聚物@银纳米壳层(PSMA@Ag)复合微球。采用傅立叶红外光谱法验证了聚多巴胺(PDA)的成功修饰。结合扫描电子显微镜(SEM)和紫外-可见光谱(UV-Vis)分析结果,发现Ag纳米壳层成功地包覆在PSMA微球的表面。将制备的PSMA@Ag复合微球作为辅助基质直接应用于MALDI-MS,成功地从0.5μL待测物样品中检测到2 pmol脯氨酸(M_w=115)和1 pmol丝氨酸(M_w=105)。研究结果证明PSMA@Ag微球对MALDI的离子化过程有促进作用,为解决MALDI-MS在分析小分子待测物时背景噪声过大,信号无法分辨的问题提供了一个有效途径。

Fabrication of PSMA@Ag Composite Microbeads and Their Application in Small Molecular Analysis Based on MALDI-MS Platform

As a powerful analysis approach,matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS) has attracted considerable attention in biomolecular analysis.However,this approach could hardly be used in the detection for samples with molecular mass lower than 500.In this work,poly(styrene-co-maleic anhydride) microbead@silver nanoshell(PSMA@Ag) composite microbeads with core-shell structure were synthesized using a polydopamine-modification method.FT-IR results demonstrated the successful coating of polydopamine(PDA).SEM images along with UV-Vis results indicated that Ag nanoparticles were uniformly modified onto the surface of PSMA microbeads.The prepared PSMA@Ag microbeads were directly applied in matrix-assisted laser desorption/ionization mass spectrometry,successfully detecting 2 pmol proline(M_w=115) and 1 pmol serine(M_w=105) in 0.5 μL sample,respectively.This work verified the positive effect of PSMA@Ag microbeads in MALDI-MS laser desorption/ionization process,and provided a promising route for MALDI analysis of the biomolecules with low molecular mass.