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Updated: Jan 31, 2026

Colorimetric Detection of Bacteria Using Litmus Test
Published on: September 17, 2016
A colorimetric and near-infrared fluorescent probe for cysteine and homocysteine detection
Xiaojing Yang1, Yingying Wang1, Mei-Xia Zhao1
1Key Laboratory of Natural Medicine and Immune-Engineering of Henan Province, Henan University, Kaifeng 475004, China.
Abstract:
By introducing the S-aryl substituents at the central carbon on heptamethine cyanine, we have developed a near-infrared fluorescent probe Cy.7-PT. The probe had the high selectivity for the colorimetric detection of Cys/Hcy with the color changing from light green to blue. Cys could be quantitatively detected and the detection limit is 0.39 μM. Cell imaging and spiked samples experiments prove that the probe Cy.7-PT is suitable for monitoring and visualizing Cys in vitro and living cells.
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