Tobias Charlie, Climent Estela, Gawlitza Kornelia, Rurack Knut
Chemical and Optical Sensing Division, Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter-Str. 11, D-12489 Berlin, Germany.
ACS Appl Mater Interfaces. 2021 Jan 13;13(1):207-218. doi: 10.1021/acsami.0c17940. Epub 2020 Dec 21.
Functional core/shell particles are highly sought after in analytical chemistry, especially in methods suitable for single-particle analysis such as flow cytometry because they allow for facile multiplexed detection of several analytes in a single run. Aiming to develop a powerful bead platform of which the core particle can be doped in a straightforward manner while the shell offers the highest possible sensitivity when functionalized with (bio)chemical binders, polystyrene particles were coated with different kinds of mesoporous silica shells in a convergent growth approach. Mesoporous shells allow us to obtain distinctly higher surface areas in comparison with conventional nonporous shells. While assessing the potential of narrow- as well as wide-pore silicas such as Mobil composition of matter no. 41 (MCM-41) and Santa Barbara amorphous material no. 15 (SBA-15), especially the synthesis of the latter shells that are much more suitable for biomolecule anchoring was optimized by altering the pH and both, the amount and type of the mediator salt. Our studies showed that the best performing material resulted from a synthesis using neutral conditions and MgSO as an ionic mediator. The analytical potential of the particles was investigated in flow cytometric DNA assays after their respective functionalization for individual and multiplexed detection of short oligonucleotide strands. These experiments revealed that a two-step modification of the silica surface with amino silane and succinic anhydride prior to coupling of an amino-terminated capture DNA (c-DNA) strand is superior to coupling carboxylic acid-terminated c-DNA to aminated core/shell particles, yielding limits of detection (LOD) down to 5 pM for a hybridization assay, using labeled complementary single-stranded target DNA (t-DNA) 15mers. The potential of the use of the particles in multiplexed analysis was shown with the aid of dye-doped core particles carrying a respective SBA-15 shell. Characteristic genomic sequences of human papillomaviruses (HPV) were chosen as the t-DNA analytes here, since their high relevance as carcinogens and the high number of different pathogens is a relevant model case. The title particles showed a promising performance and allowed us to unequivocally detect the different high- and low-risk HPV types in a single experimental run.
功能化核/壳颗粒在分析化学中备受追捧，特别是在适用于单颗粒分析的方法中，如流式细胞术，因为它们能够在一次运行中轻松实现对多种分析物的多重检测。为了开发一种强大的微珠平台，其核心颗粒能够以直接的方式进行掺杂，而外壳在用（生物）化学结合剂功能化时能提供尽可能高的灵敏度，采用收敛生长法用不同种类的介孔二氧化硅壳包覆聚苯乙烯颗粒。与传统的无孔壳相比，介孔壳使我们能够获得明显更高的表面积。在评估窄孔和宽孔二氧化硅（如Mobil组成物质编号41（MCM - 41）和圣巴巴拉无定形材料编号15（SBA - 15））的潜力时，特别是通过改变pH值以及介质盐的用量和类型，优化了更适合生物分子锚定的后者壳的合成。我们的研究表明，性能最佳的材料是在中性条件下使用MgSO作为离子介质合成的。在对颗粒进行各自功能化以用于短寡核苷酸链的单独和多重检测后，通过流式细胞术DNA分析研究了颗粒的分析潜力。这些实验表明，在偶联氨基末端捕获DNA（c - DNA）链之前，先用氨基硅烷和琥珀酸酐对二氧化硅表面进行两步修饰，优于将羧酸末端的c - DNA偶联到胺化的核/壳颗粒上，对于使用标记的互补单链靶DNA（t - DNA）1十五聚体的杂交分析，检测限低至5 pM。借助携带相应SBA - 15壳的染料掺杂核心颗粒，展示了颗粒在多重分析中的应用潜力。这里选择人乳头瘤病毒（HPV）的特征基因组序列作为t - DNA分析物，因为它们作为致癌物的高度相关性以及大量不同病原体是一个相关的模型案例。所述颗粒表现出良好的性能，使我们能够在一次实验运行中明确检测出不同的高风险和低风险HPV类型。
