A Lab-in-a-Syringe Device Integrated with a Smartphone Platform: Colorimetric and Fluorescent Dual-Mode Signals for On-Site Detection of Organophosphorus Pesticides

Abstract

Herein, a portable lab-in-a-syringe device integrated with a smartphone sensing platform was designed for rapid, visual quantitative determination of organophosphorus pesticides (OPs) via colorimetric and fluorescent signals. The device was chiefly made up of a conjugate pad labeled with cetyltrimethylammonium bromide-coated gold nanoparticles (CTAB-Au NPs) and a sensing pad modified by ratiometric probes (red-emission quantum dots@SiO 2 nanoparticles@green-emission quantum dots, rQDs@SiO 2 @gQDs probe), which was assembled through a disposable syringe and reusable plastic filter. In the detection system, thiocholine (Tch), the hydrolysis product of thioacetylcholine (ATch) by acetylcholinesterase (AchE), could trigger the aggregation of CTAB-Au NPs, resulting in a significant color change from red to purple. Then, CTAB-Au NPs flowed vertically upward and bound to the rQDs@SiO 2 @gQDs probe on the sensing pad, reducing the fluorescence resonance energy transfer effect between CTAB-Au NPs and gQDs. Meanwhile, rQDs embedded in SiO 2 NPs remained stable as internal reference fluorescence, achieving a color transition from red to green. Thus, based on the inhibition of AChE activity by OPs, a colorimetric and fluorescent dual-mode platform was constructed for on-site detection of OPs. Using glyphosate as a model, with the support of a color recognizer application (APP) on a smartphone, the ratio of red and green channel values could be utilized for accurate OP quantitative analysis ranging from 0 to 10 μM with a detection limit of 2.81 nM (recoveries, 90.8−122.4%; CV, 1.2−3.4%). Overall, the portable lab-in-asyringe device based on a smartphone sensing platform integrated sample monitoring and result analysis in the field, implying great potential for on-site detection of OPs.

Biomimic Nanozymes with Tunable Peroxidase-like Activity Based on the Confinement Effect of Metal–Organic Frameworks (MOFs) for Biosensing

“…Paper-and Gel-Based Sensors for H 2 O 2 and Glucose Detection. Developing a visual, rapid, and real-time strategy for the monitoring of targets has always been an important issue in many fields, such as environment contaminations, 34,35 food safety management, 36 and point-of-care diagnostic tests. 37 Herein, utilizing Hemin@BSA@ZIF-8, a portable and sensitive paper-based colorimetric sensor integrated with a smartphone was designed for the naked-eye and quantitative analysis of H 2 O 2 and glucose.…”

Functional Micro-/Nanostructures in Agrofood Science: Precise Inspection, Hazard Elimination, and Potential Health Risks

“…100 The prepared Atta-Eu-FITC nano probe has the advantages of high sensitivity (LOD = 19 nM), wide detection range (detection linear range of 0−25 μM), and good detection rate for TC in samples such as lake water, tap water, honey, milk, and the like. Wei et al 101 designed a laboratory device based on the integration of nanoprobes and a smartphone sensing platform for rapid and visual quantitative determination of organophosphorus pesticides (OPs) by colorimetric and fluorescence signals. The device mainly consisted of a bonding pad labeled with cetyltrimethylammonium bromide-coated gold nanoparticles (CTAB-AuNPs) and a sensing pad modified by a ratio probe (red-emission QDs@SiO 2 nanoparticles@green-emission QDs, rQDs@SiO 2 @gQDs probe).…”

Two-Dimensional Cobalt-Doped Ti3C2 MXene Nanozyme-Mediated Homogeneous Electrochemical Strategy for Pesticides Assay Based on In Situ Generation of Electroactive Substances

“…However, the excessive and irrational use of pesticides may leave pesticide residues in the environment, which threatens human health and ecosystem security. , Thus, it is necessary to develop stable and reliable analytical strategies to detect specific pesticide residues. Up to now, a variety of analytical methods for pesticide residues, − including chromatography, fluorescence, and colorimetry, have been developed. Unfortunately, the aforementioned techniques are often limited by sophisticated instrumentation, low quantum yield, photobleaching, and interference from colored substances, which may not conform to the requirement for accurate, sensitive, and high-performance sensing of pesticides.…”