3D Droplet-Based Microfluidic Device Easily Assembled from Commercially Available Modules Online Coupled with ICPMS for Determination of Silver in Single Cell.

Abstract

More recently, single-cell analysis based on ICPMS has made considerable headway while a challenge remains to differentiate single cell from doublets during the analysis. One burgeoning solution is to encapsulate single cell into droplets on the platform of the microfluidic chip. However, the manufacture of the droplet-based microfluidic chip requires sophisticated fabrication and limits its potential application. In this paper, we presented an off-the-shelf three-dimensional (3D) microfluidic device by assembling commercially available parts without any proficient manufacturing process. Uniform monodisperse microdroplet was generated from the 3D microfluidic device with a size variation of 1.5%, and the innner diameter of the 3D microfluidic device was the same as the nebulizer (150 μm). The proposed 3D microfluidic device-time-resolved ICPMS system was applied to detect silver in single AgNPs (51 nm), and the result is in good agreement with conventional acid digestion method, demonstrating the accuracy of the method. Silver uptake behaviors in HepG2 cells were then studied by incubating with Ag+ or AgNPs under biocompatible conditions. The results revealed that the cell-to-cell variability in terms of the diversity of cells incubated with AgNPs was wider than those cells incubated with Ag+ from the aspect of the content distribution of silver at the single-cell level.