ACS Sensors最新文献

A low cost, portable optical sensing platform enables rapid and sensitive detection of methyl salicylate (MeSal) in unprocessed samples. The sensing assay is based on a strong photoluminogenic response when MeSal forms a complex with a terbium cation (Tb³⁺) in aqueous buffer. The assay employs an airtight three-well sensing chamber that allows the volatile MeSal to spontaneously diffuse out of a sample well and partition into a neighboring test well where the intense green Tb-photoluminescence is detected by the naked eye or a cell phone camera. This MeSal vapor diffusion process mimics the biological airborne messenger mechanism used by distressed plants to warn their neighbors and prompt a communal defense. Within the assay chamber, the MeSal vapor diffusion acts as a purification step that separates the MeSal photoluminescent signal from the interfering sample background signal. Proof-of-concept experiments show that the optical assay can quickly distinguish a sample of commercial toothpaste that contains 0.48% MeSal from a sample that does not contain MeSal. This type of high-throughput semi-quantitative screening is increasingly mandated by regulatory agencies who have placed upper limits on the amount of added MeSal within cosmetic products. Practical utility for enzyme detection is also demonstrated by using a novel substrate molecule, MeSal-Glc, to detect the presence of the flavor-promoting enzyme β-glucosidase in almond flour, a representative food sample. Many other enzyme detection assays can likely be developed using bespoke substrate molecules that contain MeSal as a releasable reporter unit for Tb-photoluminogenic sensing.

Leukemia stem cell (LSC) phenotyping offers significant potential to enhance minimal residual disease (MRD) monitoring in acute myeloid leukemia (AML), improving therapeutic evaluation and relapse prediction. However, current approaches lack the sufficient sensitivity and specificity to reliably detect rare chemotherapy-resistant LSCs (crLSCs) or identify stem-like phenotypic states, limiting clinical translation. Here, we develop DISCERN (Dual-Aptamer-Initiated Sensing Circuit via Engineered Nanozyme), a colorimetric platform for ultrasensitive LSC phenotyping. DISCERN employs a dual-aptamer system targeting colocalized surface markers (CD33 and CD123) for high-specificity recognition. Its exceptional sensitivity (limit of detection <10 cells/mL) is achieved by a localized catalytic cascade: target-binding initiates on-site rolling circle amplification (RCA), which in turn templates the assembly of PCN-222(Fe) nanozymes that generate amplified colorimetric signals. We demonstrate that DISCERN can track phenotypic plasticity in leukemia cells and identify stem-like subsets in leukemia xenograft models. This cost-effective and robust platform provides a promising tool for AML risk stratification, relapse prediction, and precision therapy.

Aptamer (Apt)-based biosensors are promising tools for resource-limited Norovirus (NoV), where GII.4 is the predominant sub-genotype causing human infections. Considering their urgent and strict needs of on-site renewal, we present a smart regeneration strategy, inspired by the modern electronics industry, on a homemade screen-printed electrode (SPE). Aqueously prepared MXene@MWCNTs-Au-Fc (MWCNTs: multiwalled carbon nanotubes; Fc: ferrocene) and single-strand DNA (ssDNA), semi-complementary to NoV Apt, are permanently assembled onto the SPE. By incubating Apt and methylene blue (MB), Apt-ssDNA structures with MB filling are obtained. NoV competitively combines Apt, dissociates Apt-ssDNA structures, and triggers ratiometric ΔI_MB/I_Fc. Remarkably, a programmable thermal profile is written into a micro controller unit (MCU) of the SPE. With on-chip hardware resources as the heater, error amplifier, and heater driver, the temperature curve is sectionally regulated during Apt-ssDNA regeneration, concurrently promoting reaction and preventing functionalization deterioration. Besides the wide range (1-10⁶ copies mL^-1) and impressive limit of detection (0.67 copies mL^-1), this method shows significantly less I_MB loss than control (98.67% vs 80.26%). For NoV-contaminated beef and pork, the proposed results meet well with certified RT-qPCR (RSDs < 4.89%).