Biphasic Microdroplet–Microdroplet Extraction for Ultra‐Trace Enriching Analysis

Abstract

targets, which manifests immense potential for drug development, biological purification, environmental monitoring, and food safety. [8][9][10][11][12][13][14][15] The open-channel microdroplet platform with the characteristics of simple manufacture, no external complicated equipment, low sample consumption, and handy sample manipulation has been applied to cell and drug screening, materials synthesis, environmental monitoring, clinical diagnosis, and high-throughput detection. [16][17][18][19][20][21][22][23] With increasingly diversified and procedural applications, researchers are no longer satisfied with the research in an independent microdroplet, but turn to microdropletmicrodroplet contact, fusion, and information communication including aqueous two-phase detection, cell fusion, reactorcomparting, and so on. [24][25][26][27][28][29][30] Currently, the microdroplet-microdroplet research is overwhelmingly based on a single aqueous phase, which has certain limitations for low aqueous-soluble substances, complex sample matrix, and anisotropy research. The biphasic microdroplet-microdroplet system with a uniform overall microdroplet environment and double-phase microdroplet-microdroplet interface can realize interface reaction, information transmission, and material exchange. [31][32][33][34][35] For these reasons, it is imperative to develop a biphasic microdroplet-microdroplet platform, which will enormously broaden the applications of open-channel microdroplet, including liquid-phase microextraction, nanoparticle interface assembly, targeted drug delivery, and high-throughput screening, medical diagnosis, and molecular imaging. [36][37][38][39][40] Here, we demonstrated a 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFTS)/n-butyl cyanoacrylate (n-BCA) modified mini-pillar platform for biphasic (aqueous and organic) microdroplet-microdroplet enrichment and extraction. PFTS was uniformly bonded by n-BCA (adhesive) to polydimethylsiloxane (PDMS) mini-pillar prepared by template casting method. After coating, the mini-pillar surface displayed multilayer concave microstructure with ultralow surface energy, which enhanced the surface hydrophobicity and from lipophilicity to oleophobicity so that it can compatible with biphasic reagents persistently despite rotation and inversion. The microdropletsmicrodroplets array was subsequently established based on the platform and the applicable extraction parameters for implementing highly efficient biphasic extraction were evaluated. As a proof-of-concept, we achieved extraction analysis of multiple analytes in single-phase, double-phase, and enrichment Enriching trace targets from trace samples is essential for analytical chemistry. Here, a mini-pillar platform for biphasic (aqueous and organic) microdroplet-microdroplet extraction for enrichment analysis is demonstrated. Such mini-pillars with biphasic hydrophobicity can anchor the biphasic microdroplets (organic or aqueous) regardless of rotation and inversion. Methylene blue (MB) and Nile red (NR) are extracted and analy...

Integrated phase separation in microliter droplets for ultratrace-enriching biomarker analysis

“…10,11 In addition, the surface of the minipillars can be used for biosensing purposes through colorimetric, electrochemical, SERS, and fluorescence signals, enabling the detection of target analytes. 10,[12][13][14][15][16][17] Although the minipillars provide an excellent platform for carrying and detecting trace samples, enrichment of low abundant biomarkers in trace samples for sensitive detection remains a challenge.…”

Nanoextraction based on surface nanodroplets for chemical preconcentration and determination

“…9,10 Due to the large active surface area, microscopic droplets are of great interest for preconcentration of target analytes across the droplet-liquid interface at extremely low concentrations. [11][12][13][14] The enhanced preconcentration depends on the partition of the compound between droplet liquid and surrounding sample liquid.…”