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Buprofezin (BUP) is an effective insecticide against Homopteran and Thysanoptera pests. However, exposure to BUP may result in several harmful effects on the non-target organism including human body, such as hepatotoxicity and DNA damage. Therefore, development of a reliable analytical method for BUP holds paramount importance. This study presents a novel albumin-based supramolecular biosensor, DPP@ALB, designed for the sensitive detection of BUP in environmental matrices, including water, soil, and real food samples. The features of this biosensor include a fast response, high sensitivity, and visually detectable fluorescence color change, enabling on-site detection of BUP based on the portable paper strips and 3D-printed miniaturized testing system. Overcoming challenges associated with the low chemical reactivity of BUP, this supramolecular biosensor emerges as the very first fluorescent sensor for efficient and reliable monitoring of BUP with applications in broader areas of environmental analysis and food safety. • The first ratiometric supramolecular biosensor for the detection of buprofezin. • The response is rapid (< 10 s) and the limit of detection is lower than 0.66 ppm. • Ratiometric response to buprofezin originates from the formation of co-binding albumin complex. • On-site detection of buprofezin has been achieved using a portable sensing device. • This biosensor enables detection of buprofezin in food samples and environmental matrices. [ABSTRACT FROM AUTHOR]

Human serum albumin (HSA) is an important biomarker for chronic kidney disease, cardiovascular disease, and liver disease, yet its measurement is subject to the routine clinical laboratories. Pioneering studies have demonstrated that few of the ratiometric fluorescent probes enable the point-of-care (POC) testing of HSA with the aid of affordable domestic apparatuses. Still, the lack of choices of fluorophores restricts the development of such assay. In the present work, we propose two design strategies on the typical donor-acceptor fluorescent probe via the structural engineering. The results suggest that replacement of the dimethylamino group in probe by the weaker electron donating thiophene group can effectively tune the fluorescence response to HSA from off-on to ratiometric, ideally suiting for the POC application. The screened fluorescent probe is capable of detecting HSA with the features of fast response (< 10 s), stable output, high sensitivity (limit of detection = 54 nM), tunable detection range, and great anti-interference. Moreover, the ratiometric fluorescence response to HSA can be recorded and analyzed by the portable miniaturized paper-based or 3D-printed devices at the point of need. The success of structural engineering in the present study provides an efficient way to rationally regulate the fluorescence response mode of the donor-acceptor probes. [Display omitted] ● A donor-acceptor-based probe STF for ratiometric detection of HSA is reported. ● The relationship between structure and spectroscopic properties of probe is revealed. ● STF enables the rapid, sensitive, and selective detection of HSA. ● The portable paper-based testing devices and 3D-printed miniaturized devices are integrated. ● The point-of-care testing of HSA is achieved. [ABSTRACT FROM AUTHOR]

• The strategy of donor engineering to enhance fluorescence brightness is reported. • The methylpiperazine-substituted flavonoid shows high fluorescence brightness in water. • A novel fluorescent probe can sense cysteine both in water and in living cells. Increasing demand for detecting environmental and biological analytes in aqueous solutions based on fluorescent probes has raised the bar for the fluorophores used. Especially, the twisted intramolecular charge transfer (TICT) state of fluorophore can trigger the formation of a charge-separated non-emissive specie, leading to a low fluorescence brightness. In this work, we performed a simple donor engineering on the flavonoid-based fluorophores to regulate the TICT formation. A systematic study on relationship between donor structure and photophysical properties has been carried out. Among a series of flavonoids, the methylpiperazine-substituted one exhibited the strongest fluorescence brightness in water since the methylpiperazine could rigidify the rotation of donor moiety to suppress TICT state. Moreover, a novel fluorescent probe based on this flavonoid successfully realized the cysteine detection both in water and in living cells. This work confirmed the validity of design strategy by inhibiting TICT to enhance the fluorescence brightness, and also provided a practical flavonoid-based fluorophore for further bioimaging applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flavonol-based small-molecule fluorescent probes are reviewed. • ƒÜ The unique photophysical process of flavonol and its advantages in probe design are introduced. • ƒÜ The design mechanism of flavonol-based fluorescent probes has been discussed and categorized. • ƒÜ The sensing performances and applications of probes are summarized. Flavonols, named as 3-hydroxyl-2-phenyl-1-benzopyran-4-one, are important natural botanical functional pigments widely distributing in fruits, vegetables, and flowers. Owing to intramolecular hydrogen bond, the flavonols can undergo the excited-state intramolecular proton transfer (ESIPT) process upon irradiation, leading to unique environmental-sensitive dual emissions, which makes flavonol an ideal fluorophore skeleton for probe design. In this paper, we summarized the recent progress of flavonol-based small-molecule fluorescent probes for diverse sensing applications, including detection of anions, cations, reactive biological species, proteins, DNAs, environmental hazards, and microenvironmental factors. This review highlighted the basic characteristics of flavonol probes in the respect of design principles, photophysical processes, sensing mechanism, sensing performances, and biological applications. The present review article aims to offer a comprehensive summary for researchers to inspire new probe design, and push forward the advancement of flavonol-based fluorescent probes. [ABSTRACT FROM AUTHOR]

Determination of albuminuria at the point-of-care can provide an early diagnosis and monitor the quality management of numerous diseases. Yet for most fluorescent probes, the detection accuracy is not reliable, since urine itself exhibits very strong endogenous fluorescence causing a considerable interference on response signal. We herein report a novel fluorescent probe DNC with an enhanced environmental sensitivity and red-shifted wavelength (> 600 nm) by enlarging its transition dipole moment. The DNC could selectively bind with drug sites of albumin, causing a significant fluorescence enhancement without the interference from urinary fluorescence. Based on this sensing approach, albuminuria could be directly diagnosed at the point-of-care by using a simple homemade test system (even by naked eyes) without complicate pretreatment of urine. [Display omitted] • A novel fluorescent probe enables determination of albuminuria at point-of-care. • This fluorescent probe can give red-emissive response to albumin without the interference from urinary fluorescence. • The A2-level and A3-level albuminuria can be discriminated by naked eyes using this probe. [ABSTRACT FROM AUTHOR]