Color-Coded Single-Particle Pyrophosphate Assay with Dark-Field Optical Microscopy

Abstract

In this work, we demonstrate a convenient yet sensitive color-coded single-particle detection method for the quantification of pyrophosphate (PPi) by using single gold nanoparticle (GNP) as the probe. The design is based on GNP-dependent catalytic deposition of Cu onto the surface of GNPs with reduced nicotinamide adenine dinucleotide (NADH). Without PPi, Cu can be directly reduced to Cu through the gold-catalyzed oxidization of NADH. In the presence of PPi, the coating process is impeded due to the strong coordination capability of PPi with Cu. The selective coating of Cu shell onto the GNPs surface results in the extraordinary red-shift of localized surface plasmon resonance from individual GNPs. By quantitatively counting the fraction of yellow particles with color-coded dark-field optical microscopy, the trace amounts of PPi in solution can be accurately quantified. The limit-of-detection is as low as 1.49 nM with a linear dynamic range of 0-4.29 μM, which is much lower than the spectroscopic measurements in bulk solution. In artificial urine sample, good recovery efficiency was achieved. As a consequence, the method demonstrated herein will find promising applications for the ultrasensitive detection of target biomolecules under biological milieu in the future.

Individual Plasmonic Nanoprobes for Biosensing and Bioimaging: Recent Advances and Perspectives

“…[ 38–80 ] To satisfy the different requirements for the DFM technique, a variety of nanoprobes, including gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), copper nanoparticles (CuNPs), and aluminum (Al)‐based nanostructures have been synthesized. [ 81–85 ] The most commonly employed nanoprobes are AuNPs and AgNPs because of their excellent ability to support plasmons. With the assistance of suitable PNPs, which convert chemical or physical stimuli in their local environment to Rayleigh scattering light signals in a highly efficient way, DFM techniques have been widely applied in studying dynamic systems with rapid kinetics and quantification of biomolecules.…”

Copper (II) Ion-Modified Gold Nanoclusters as Peroxidase Mimetics for the Colorimetric Detection of Pyrophosphate

“…Pyrophosphate (PPi) is a byproduct of the hydrolysis of nucleoside triphosphates and plays an important role in many biological reactions [ 1 ]. According to previous studies, the level of PPi in human urine or synovial fluid has been associated with certain diseases, including chondrocalcinosis, urolithiasis, and even cancer [ 2 , 3 ]. PPi has been shown to inhibit the formation of calcium oxalate and calcium phosphate crystals in the urethra [ 4 ].…”

“…Until now, a variety of different techniques have been devoted to conducting PPi detection, including fluorescence spectroscopy [ 5 , 6 , 7 ], surface-enhanced Raman-scattering (SERS) assays [ 8 ], colorimetric sensing [ 9 , 10 , 11 ], chemiluminescence [ 12 ], electrochemical analysis [ 13 , 14 ], and dark-field optical microscopy (DFM) [ 3 ]. The principle of most of the above methods is based on the complexation of PPi with metal ions (Al 3+ [ 15 ], Fe 3+ [ 9 , 16 ], Ca 2+ [ 11 ], Zn 2+ [ 17 ], and Cu 2+ [ 5 , 6 , 10 , 12 , 13 , 18 ]), as PPi is a good complexing agent.…”

Recent advances of single molecule/particle imaging with optical microscopic methods

“…随后, 该课题组利用Qdots的荧光特性检测了肾素和蛋白激 酶等生物分子 [48,49] . 作为本课题组的重要研究方向之 一, 为了实现生物分子的超灵敏检测, 本课题组一直 致力于新颖纳米探针的开发以及超灵敏检测方法的优 化. Li等 [50] 合成了尺寸均一、分散性良好的上转换纳 米颗粒(UCNPs ; (B) 基于Cu 2+ 在GNPs表面的催 化沉积检测焦磷酸盐 [45] ; (C) 基于单颗粒计数法检测PSA的机理图 [50] ; (D) 基于单分子荧光漂白技术超灵敏检测腺苷 [51] ; (E) 基 于核酸短暂杂交检测端粒酶的示意图、在端粒酶存在和不存在时的单分子荧光随时间变化曲线 [52] (网络版彩图) .…”

“…(A) Schematic illustration of biomarker detection using scattering-based single particle intensity measurement with a dark-field microscope[44]. (B) Schematic diagram of the light path for the optical microscopic imaging of single nanoparticle and the principle of the color-coded SPD for PPi assay[45]. (C) Schematic diagram of the light path for the optical microscopic imaging of UCNPs and the principle of digital immunosorbent assay by single-particle enumeration[50].…”