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As a major hazardous additive released from microplastics and nanoplastics, identifying dibutyl phthalate (DBP) in complex matrices attracts a growing concern in environmental monitoring and food safety. For the first time, Cu 2 O/Cu 3 SnS 4 nanoflower is prepared and serves as the photoactive material which can be constructed as a smartphone-based photoelectrochemical (PEC) point-of-care test (POCT). Effectively matching energy levels between Cu 2 O and Cu 3 SnS 4 accelerated the transfer of photogenerated electron-hole pairs, significantly improving the intelligent PEC POCT performance. The novel Cu 2 O/Cu 3 SnS 4 has proven to be the Z-scheme heterojunction by density functional theory calculation. A competitive immunoassay has been realized on a Cu 2 O/Cu 3 SnS 4 modified electrode, dramatically decreasing the photocurrent signal and enhancing POCT sensitivity. The smartphone has been used to record and transfer PEC results. Under optimal conditions, the PEC POCT exhibited a satisfying linear range (0.04–400 ng/mL) and a low detection limit of 7.94 pg/mL in real samples, together with excellent stability, repeatability, reproducibility and selectivity. The PEC POCT system provides good performance and practicability in determining DBP in water and edible oil samples. This proposal provides a practical strategy for the intelligent POCT for environment monitoring and food safety. [Display omitted] • Dibutyl phthalate (DPB) were determined by Cu 2 O/Cu 3 SnS 4 -based PEC POCT. • The Z-scheme transfer pathway of Cu 2 O/Cu 3 SnS 4 was clarified via DFT. • This intelligent POCT platform showed excellent LODs in DPB detection. • DPB in real water and edible oil samples were determined with satisfactory results. [ABSTRACT FROM AUTHOR]

Growing studies focusing on nuclear acid detection via the emerging CRISPR technique demonstrate its promising application. However, limited works solve the identification of non-nucleic acid targets, especially multiple small molecules. To address challenges for point-of-care testing (POCT) in complex matrices for healthcare, environment, and food safety, we developed CRISPR Cas12a-powered highly sensitive, high throughput, intelligent POCT (iPOCT) for multiple small molecules based on a smartphone-controlled reader. As a proof of concept, aflatoxin B1 (AFB1), benzo[a]pyrene (BaP), and capsaicin (CAP) were chosen as multiple targets. First, three antigens were preloaded in independent microwells. Then, the antibody/antigen-induced fluorescent signals were consecutively transferred from the biotin-streptavidin to CRISPR/Cas12a system. Third, the fluorescent signals were recorded by a smartphone-controlled handheld dark-box readout. Under optimization, detection limits in AFB1, BaP, and CAP were 0.00257, 4.971, and 794.6 fg/mL with wide linear ranges up to four orders of magnitude. Using urine, water, soybean oil, wheat, and peanuts as the complex matrix, we recorded high selectivity, considerable recovery, repeatability, and high consistency comparison to HPLC-MS/MS methods. This work promises a practical intelligent POCT platform for multiple targets in lipid-soluble and water-soluble matrices and could be extensively applied for healthcare, environment, and food safety. An intelligent CRISPR/Cas12-empowered immune biosensor was developed for detecting aflatoxin B1, benzo[a]pyrene, and capsaicin in clinical, environmental, and food samples via a smartphone-controlled handheld dark-box readout. [Display omitted] [ABSTRACT FROM AUTHOR]

Complex nanoparticles with hybrid forms of quantum dots and nano-scale templates are highly interesting due to various functionalities and broad applications in point-of-care testing (POCT). High sensitivity and throughput are significant for POCT in clinical applications and food safety, especially for determining multiple targets in complex matrices. Here, we developed the labyrinth-like quantum dot nanobeads (LQDBs) with controlled size, enhanced loading capacity and an intelligent mobile detection format. We reported a smartphone readout using color-selective LQDBs as fluorescent labels for POCT of dual targets in paper-test format. The labyrinth-like nanobeads assembled with QDs provided high colloidal stability, facile functionalization, and a rough surface for more binding sites to monoclonal antibodies enabled by a thin silica layer coating. Using LQDB, the POCT of dual targets was developed assisted with an in-house application on a smartphone. This assay detected aflatoxin B 1 (AFB 1) and zearalenone (ZEN) within 10 min using a competitive immunoassay. The LODs for urine and agricultural products were recorded as 0.002 and 0.02 ng/mL for AFB 1 and ZEN, respectively. Reasonable specificity, repeatability, reproducibility, and validation results were recorded in real samples. This biosensing platform can be widely suitable in clinical healthcare and food safety applications. • A sensitive smartphone-based intelligent sensing strategy for multiple targets. • Labyrinth-like quantum dot nanobeads as fluorescent labels. • Multiple mycotoxins detection within 10 min for health care and food safety. [ABSTRACT FROM AUTHOR]

Complex nanoparticles with hybrid forms of quantum dots and nano-scale templates are highly interesting due to various functionalities and broad applications in point-of-care testing (POCT). High sensitivity and throughput are significant for POCT in clinical applications and food safety, especially for determining multiple targets in complex matrices. Here, we developed the labyrinth-like quantum dot nanobeads (LQDBs) with controlled size, enhanced loading capacity and an intelligent mobile detection format. We reported a smartphone readout using color-selective LQDBs as fluorescent labels for POCT of dual targets in paper-test format. The labyrinth-like nanobeads assembled with QDs provided high colloidal stability, facile functionalization, and a rough surface for more binding sites to monoclonal antibodies enabled by a thin silica layer coating. Using LQDB, the POCT of dual targets was developed assisted with an in-house application on a smartphone. This assay detected aflatoxin B 1 (AFB 1) and zearalenone (ZEN) within 10 min using a competitive immunoassay. The LODs for urine and agricultural products were recorded as 0.002 and 0.02 ng/mL for AFB 1 and ZEN, respectively. Reasonable specificity, repeatability, reproducibility, and validation results were recorded in real samples. This biosensing platform can be widely suitable in clinical healthcare and food safety applications. • A sensitive smartphone-based intelligent sensing strategy for multiple targets. • Labyrinth-like quantum dot nanobeads as fluorescent labels. • Multiple mycotoxins detection within 10 min for health care and food safety. [ABSTRACT FROM AUTHOR]

Designing a photoelectrochemical (PEC) biosensor with preponderant sensitivity and anti-interference is a challenge for detecting small molecules in real samples with complex matrices. To this end, the Bi 2 O 3 /CuBi 2 O 4 was synthesized in one step to enhance visible light's absorption ability, transferring the interfacial carrier's efficiency, a high-active Z-scheme heterojunction, and a photocathode biosensor was proposed. For the first time, we used the density functional theory to verify a Z-scheme transfer pathway of photogenerated electrons in Bi 2 O 3 /CuBi 2 O 4 and the energy band structure of Bi 2 O 3 and CuBi 2 O 4 , respectively. Bi 2 O 3 /CuBi 2 O 4 -based PEC biosensor was developed for competive immunoassay of small molecular, aflatoxin B1 (AFB1) as an example, resulting in a low detection limit of 297.4 fg/mL and a linear range of 1.4 pg/mL-280 ng/mL in urine, water, peanut, and wheat samples. Using spiked experiments, the satisfied repeatability, reproducibility, stability, and specificity of the Bi 2 O 3 /CuBi 2 O 4 -based PEC biosensor indicated a promise for application in health care, the environment, and food. [ABSTRACT FROM AUTHOR]