The red seaweed Pyropia yezoensis is a marine crop of important economic value and is widely cultivated in the coastal areas of northern China. The current seedling-raising system relies on the germination of conchospores, a process not fast enough to meet the increasing demand from farmers. In this study, we developed a monospore-dependent seedling method based on the asexual reproduction of the Pyropia thallus. The Pyropia thallus was physically sectioned into small pieces (microthalli) that were cultivated at 15 °C. The algal cells in the microthalli became morphologically condensed, underwent cell division, and then developed into monospores on the 5th day. The monospores were able to attach to the seeding rope in 24 h and germinated into healthy thalli. To optimize the efficiency of monospore release, we tested the effect of temperature and the size and original positions of the microthalli as well as the age of the mother thallus. Microthalli with a size of 30–50 cells from the middle and apex of 21-day-old thalli cultivated at 15 °C yielded the optimum production of monospores. Theoretically, in this thallus-to-thallus seeding strategy, 0.1 g of thallus could produce at least 10⁷ monospores, with the same number of offspring thallus seedlings. Taking all of these advantages together, including the high efficiency, short time, low cost and easy operation, this physical sectioning method could serve as a promising seed source especially for new cultivars with superior traits in Pyropia farming and rapid replenishment of seedlings when thalli undergo disastrous diseases.

Herein, we developed a paper-based smart sensing chip for the real-time, visual, and non-destructive monitoring of food freshness using a ratiometric aggregation-induced emission (AIE) luminogen (i.e., H⁺MQ, protonated 4-(triphenylamine)styryl)quinoxalin-2(1H)-one) as pH sensitive indicators. Upon exposure to amine vapors, the deprotonation of H⁺MQ occurs and triggers its color change from blue to yellow, with the fluorescence redshift from blue to amaranth. Consequently, we successfully achieved the sensitive detection of ammonia vapors by recording the bimodal color and fluorescence changes. Given the high sensitivity of H⁺MQ to ammonia vapor, a paper-based smart sensor chip was prepared by depositing H⁺MQ on the commercial qualitative filter paper through a physical deposition strategy. After being placed inside the sealed containers, the developed H⁺MQ-loaded paper chip was applied to the real-time monitoring of biogenic amine contents according to its color difference and ratio fluorescence change. The detection results were further compared with those obtained by the high-performance liquid chromatography method, which verified the feasibility of the designed paper chip for the food spoilage degree evaluation. Briefly, this work indicates that the designed H⁺MQ-loaded paper chip could be a promising approach for improving food freshness monitoring.

Introduction: The rapid and accurate identification of Mycobacterium tuberculosis (MTB) is essential for effective tuberculosis (TB) control. However, conventional diagnostic methods for MTB suffer from limitations such as low sensitivity, poor specificity, high cost, reliance on specialized instruments, and complex, time-consuming procedures. To address these challenges, there is an urgent need for a simple, rapid, and highly sensitive detection method that can be deployed in point-of-care settings.Methods: We developed a one-pot biosensing system combining recombinase polymerase amplification (RPA) and CRISPR/Cas12a-driven G4-hemin self-assembly for the colorimetric detection of MTB. Glycerol was employed as a phase-separation barrier to prevent interference between RPA amplification and CRISPR/Cas12a trans-cleavage. A single-stranded DNA (ssDNA) probe, designed to self-assemble with ssDNA-hemin into G4-hemin nanozymes upon CRISPR/Cas12a-mediated cleavage, served as the reaction substrate. The ssDNA-hemin further enhanced the catalytic activity of the generated G4-hemin DNAzyme. The entire assay was completed in a single step within 60 min without requiring complex instrumentation.Results and Discussion: Under optimized conditions, the biosensing system achieved ultrasensitive naked-eye detection of MTB with a limit of detection (LOD) of 10 copies/μL, comparable to traditional four-step fluorescent assays. Clinical validation using 104 patient samples demonstrated high concordance with standard diagnostic methods. This approach combines the advantages of recombinase polymerase amplification (RPA), CRISPR/Cas12a specificity, and G4-hemin DNAzyme-based colorimetric signal amplification, enabling simple, equipment-free visual detection. Given its speed, sensitivity, and ease of use, this biosensing system holds significant promise for point-of-care MTB nucleic acid testing in resource-limited settings.