Related Experiment Video
Updated: Sep 7, 2025
The Visual Colorimetric Detection of Multi-nucleotide Polymorphisms on a Pneumatic Droplet Manipulation Platform
Published on: September 27, 2016
Identification of Mycoplasma pneumoniae by DNA-modified gold nanomaterials in a colorimetric assay
Dapeng Qin1, Qiuping Gong2, Xin Li1
1Department of Inspection, General Hospital of TISCO, Taiyuan, 030008, China.
Abstract:
Mycoplasma pneumoniae is a highly infectious bacterium and the major cause of pneumonia especially in school-going children. Mycoplasma pneumoniae affects the respiratory tract, and 25% of patients experience health-related problems. It is important to have a suitable method to detect M. pneumoniae, and gold nanoparticle (GNP)-based colorimetric biosensing was used in this study to identify the specific target DNA for M. pneumoniae. The color of GNPs changes due to negatively charged GNPs in the presence of positively charged monovalent (Na+ ) ions from NaCl. This condition is reversed in the presence of a single-stranded oligonucleotide, as it attracts GNPs but not in the presence of double-stranded DNA. Single standard capture DNA was mixed with optimal target DNA that cannot be adsorbed by GNPs; under this condition, GNPs are not stabilized and aggregate at high ionic strength (from 100 mM). Without capture DNA, the GNPs that were stabilized by capture DNA (from 1 μM) became more stable under high ionic conditions and retaining their red color. The GNPs turned blue in the presence of target DNA at concentrations of 1 pM, and the GNPs retained a red color when there was no target in the solution. This method is useful for the simple, easy, and accurate identification of M. pneumoniae target DNA at higher discrimination and without involving sophisticated equipment, and this method provides a diagnostic for M. pneumoniae.
Insights
A new gold nanoparticle (GNP) colorimetric biosensor accurately detects Mycoplasma pneumoniae DNA. This simple, equipment-free method offers a rapid diagnostic tool for identifying this common cause of childhood pneumonia.
Area of Science:
- Biotechnology
- Nanotechnology
- Microbiology
Background:
- Mycoplasma pneumoniae is a significant cause of pneumonia, particularly in children.
- Infectious M. pneumoniae affects the respiratory tract, leading to health issues in 25% of patients.
- Accurate detection methods for M. pneumoniae are crucial for timely diagnosis and treatment.
Purpose of the Study:
- To develop a simple, accurate, and equipment-free method for detecting Mycoplasma pneumoniae DNA.
- To utilize gold nanoparticle (GNP)-based colorimetric biosensing for M. pneumoniae identification.
- To establish a diagnostic tool for M. pneumoniae detection.
Main Methods:
- Gold nanoparticles (GNPs) were employed for colorimetric detection of specific M. pneumoniae DNA targets.
- GNP color changes were observed based on ionic strength and the presence of single-stranded or double-stranded DNA.
- The assay involved mixing capture DNA with target DNA, observing GNP aggregation or stabilization under high ionic strength (100 mM NaCl).
Main Results:
- GNPs aggregated (color change) in the presence of target DNA at concentrations as low as 1 pM.
- GNPs remained stable (red color) in the absence of target DNA.
- The method demonstrated high discrimination and accuracy for M. pneumoniae DNA detection.
Conclusions:
- GNP-based colorimetric biosensing provides a sensitive and specific method for M. pneumoniae DNA detection.
- This technique offers a simple, rapid, and cost-effective diagnostic approach for M. pneumoniae infections.
- The developed biosensor eliminates the need for sophisticated laboratory equipment, facilitating point-of-care diagnostics.
