Related Experiment Video
Updated: Mar 7, 2026
12:25
Counting Proteins in Single Cells with Addressable Droplet Microarrays
Published on: July 6, 2018
9.0K
Convection-Driven Pull-Down Assays in Nanoliter Droplets Using Scaffolded Aptamers
Xiangmeng Qu1,2, Hongbo Zhang2,3, Hong Chen4
1Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University , 500 Dongchuan Road, Shanghai 200241, P. R. China.
Analytical Chemistry
|February 17, 2017
Summary
We developed a rapid DNA nanostructure-supported aptamer pull-down (DNaPull) assay for analyzing single cells. This convective flux method analyzes nano- to picoliter droplets in under 5 minutes, improving efficiency for bioactive molecule detection.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Microfluidics
Background:
- Developing rapid, biocompatible tools for single-cell analysis is a significant challenge in cellular studies.
- Existing methods often lack the speed and sensitivity required for analyzing minute biological samples.
- A need exists for innovative analytical platforms capable of handling ultra-low sample volumes.
Purpose of the Study:
- To develop a rapid, DNA nanostructure-supported aptamer pull-down (DNaPull) assay for analyzing the contents of nano- or picoliter droplets.
- To leverage convective flux in a glass capillary for accelerated reaction times.
- To demonstrate the assay's capability for analyzing various bioactive molecules and single-cell contents.
Main Methods:
- Utilized a DNA nanostructure-supported aptamer pull-down (DNaPull) assay within a glass capillary.
- Implemented convective flux to enhance reaction kinetics, enabling rapid analysis.
- Integrated a microfluidic device to compartmentalize live cells into nanoliter droplets for single-cell analysis.
Main Results:
- The DNaPull assay demonstrated efficient pull-down of target molecules, significantly improved by scaffolded aptamers.
- Convective flux enabled complete reactions in under 5 minutes, an 18-fold improvement over diffusive methods.
- The assay successfully detected small molecules (ATP, LOD 1 μM), a drug (cocaine, LOD 1 μM), and a biomarker (thrombin, LOD 0.1 nM).
- Analyzed intracellular ATP levels from 0–5 lysed HNE1 cells within nanoliter droplets, estimating intracellular ATP at ~3.4 mM.
Conclusions:
- The convection-driven DNaPull assay provides a rapid and sensitive analytical platform for diverse bioactive molecules.
- The microfluidic integration allows for the analysis of molecules from discrete numbers of single cells.
- This analytical platform represents a new paradigm in biosensor design, valuable for single-cell studies.
