Related Experiment Video
Updated: Feb 15, 2026
08:23
Design and Development of Aptamer–Gold Nanoparticle Based Colorimetric Assays for In-the-field Applications
Published on: June 23, 2016
12.8K
Gold nanoparticle-based colorimetric sensing of dipicolinic acid from complex samples
Mirza Muhammad Fahad Baig1, Yu-Chie Chen2
1Department of Applied Chemistry, National Chiao Tung University, 1001 University Road, Hsinchu, 300, Taiwan.
Analytical and Bioanalytical Chemistry
|January 26, 2018
Summary
A new colorimetric method using gold nanoparticles detects dipicolinic acid (DPA) without interference from phosphates. This advancement offers sensitive and selective DPA analysis in complex samples like soil and bacterial spores.
Area of Science:
- Nanotechnology
- Analytical Chemistry
- Biochemistry
Background:
- Dipicolinic acid (DPA) is a neurotoxic compound found in bacterial spores.
- Existing DPA detection methods lack selectivity in the presence of phosphates.
- Developing phosphate-resistant DPA detection is crucial for accurate analysis.
Purpose of the Study:
- To develop a novel, phosphate-insensitive colorimetric method for dipicolinic acid (DPA) detection.
- To utilize gold nanoparticles (AuNPs) complexed with Ca2+ as a sensing platform.
- To enable sensitive and selective quantification of DPA in environmental and biological samples.
Main Methods:
- A colorimetric assay employing glutathione-capped gold nanoparticles (AuNPs@GSH) complexed with Ca2+ was developed.
- AuNP aggregation, indicated by a color change from red to purple, was induced by Ca2+.
- DPA addition reversed the aggregation and color change due to its high affinity for Ca2+.
Main Results:
- The developed method demonstrated high selectivity for DPA, unaffected by phosphate ions.
- A limit of detection as low as ~2 μM for DPA was achieved.
- Successful quantitative detection of DPA in soil and Bacillus cereus spore samples was demonstrated.
Conclusions:
- This gold nanoparticle-based colorimetric method provides a robust platform for phosphate-insensitive DPA detection.
- The assay offers a sensitive, selective, and visually discernible approach for DPA analysis.
- The method's applicability to real-world samples like soil and spores highlights its practical utility.
Related Concept Videos
02:33Lewis Acids and Bases
48.5K
In 1923, G. N. Lewis proposed a generalized definition of acid-base behavior in which acids and bases are identified by their ability to accept or to donate a pair of electrons and form a coordinate covalent bond.
A coordinate covalent bond (or dative bond) occurs when one of the atoms in the bond provides both bonding electrons. For example, a coordinate covalent bond occurs when a water molecule combines with a hydrogen ion to form a hydronium ion. A coordinate covalent bond also results when...
A coordinate covalent bond (or dative bond) occurs when one of the atoms in the bond provides both bonding electrons. For example, a coordinate covalent bond occurs when a water molecule combines with a hydrogen ion to form a hydronium ion. A coordinate covalent bond also results when...
48.5K
02:54Ions as Acids and Bases
26.8K
Salts with Acidic Ions
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
26.8K
03:26Acids, Bases and Neutralization Reactions
64.0K
An acid-base reaction is one in which a hydrogen ion, H+, is transferred from one chemical species to another. Such reactions are of central importance to numerous natural and technological processes, ranging from the chemical transformations within cells or lakes and oceans to the industrial-scale production of fertilizers, pharmaceuticals, and other substances essential to the society.
64.0K
02:58Bronsted-Lowry Acids and Bases
106.2K
The acid-base reaction class has been studied for quite some time. In 1680, Robert Boyle reported traits of acid solutions that included their ability to dissolve many substances, to change the colors of certain natural dyes, and to lose these traits after coming in contact with alkali (base) solutions. In the eighteenth century, it was recognized that acids have a sour taste, react with limestone to liberate a gaseous substance (now known to be CO2), and interact with alkalis to form neutral...
106.2K
02:23Acid-Base Titration Curves
141.9K
A titration curve is a plot of some solution property versus the amount of added titrant. For acid-base titrations, solution pH is a useful property to monitor because it varies predictably with the solution composition and, therefore, may be used to monitor the titration’s progress and detect its endpoint. Acid-base titration can be performed with a strong acid and a strong base, a strong acid and a weak base, or a strong base and a weak acid.
For a titration carried out for 25.00 mL of...
For a titration carried out for 25.00 mL of...
141.9K
03:22Strong Acid and Base Solutions
36.2K
A strong acid is a compound that dissociates completely in an aqueous solution and produces a concentration of hydronium ions equal to the initial concentration of acid. For example, 0.20 M hydrobromic acid will dissociate completely in water and produces 0.20 M of hydronium ions and 0.20 M of bromide ions.
36.2K