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Abstract Light emitting diodes of wavelength 410 nm were used to inactivate Listeria monocytogenes stains on paperboard, an increasingly popular food packaging material. The integrity of the cell membranes was examined using differential fluorescent staining. Scanning electron microscopy (SEM) was used to obtain a deeper understanding of L. monocytogenes stain formation on paperboard and the damage caused to the cells by the LEDs. While the planktonic L. monocytogenes population could be completely inactivated following a brief lag phase that lasted about 20 min, the illumination of the sessile population left some persisters despite immediate commencement of the inactivation. Planktonic populations of inocula sized 3, 5 and 7 log CFU/mL were reduced below the detection limit in 54, 80 and 84 min respectively, whereas it took 120 and 390 min to reach constancy in the sessile populations of inocula sized 5 and 7 log CFU/cm2. The number of membrane-damaged cells was seen to increase with the illumination time. SEM images provided evidence of the protection conferred by the stain on the underlying cells. This study demonstrates that blue LEDs have the potential to reduce the risk of L. monocytogenes contamination from paperboard cartons under refrigeration. Highlights • 410 nm LEDs inactivated sessile L. monocytogenes cells on paperboard. • The inactivation kinetics were biphasic, with a shoulder and a tail. • Differential fluorescent staining revealed membrane injury to the Listeria cells. • SEM images provided insights into bacterial attachment and photodynamic damage. [ABSTRACT FROM AUTHOR]

Flexible electronics have gained significant interest due to their potential applications in wearable devices, biomedical sensors, and flexible displays. This study explores the combination of MXene and cellulose nanocrystals (CNC) for the development of flexible, conductive, and degradable materials. CNC and MXene are high-performance nanomaterials with known degradability. CNC can self-assemble into highly ordered layers and act as an ideal structural companion for enabling large surface MXene-based devices with outstanding performance. Three fabrication routes are explored in this work: self-assembly, drop casting, and dip coating. The mechanical and electrical properties of the CNC-MXene composite films were assessed. Tensile testing revealed that dip-coated films in high-loadings of MXene could exhibit enhanced toughness of up to 1.9 MJ‧m−3, higher than pure MXene or CNC. The electrical conductivity of the films varied depending on MXene concentration and drying, exhibiting superior conductivity in self-assembly with higher MXene loading and rapid drying that prevents oxidation. Self-assembled MXene-CNC with a 1:3 MXene-to-CNC ratio maintained high conductivity of 2.2 × 105 S‧m−1. Zeta potential measurements indicate that CNC enhances the stability of MXene dispersion. These findings demonstrate good synergy between CNC and MXenes for applications in flexible, transparent, and environmentally degradable electronic. Composites of cellulose nanocrystals with MXene were fabricated in three different ways: self-assembly, drop casting and dip coating. These composites can be used to tailor flexible, degradable and partially transparent films with controlled conductivity. [Display omitted] [ABSTRACT FROM AUTHOR]

Fruit skin reticulation is accompanied by the formation of a wound-periderm tissue made of suberized cells. The regulatory networks overseeing skin reticulation during fruit development were extensively studied, yet how reticulation affects post-harvest traits remains unknown. We addressed this notion using the common Cucumis sativus and the skin-cracked Sikkim (Cucumis sativus var. sikkimensis) cucumbers. Light and electron microscopy in consort with gas chromatography-mass spectrometry revealed that sativus fruit skin is made of the typical cutin polymer, while the skin of sikkimensis fruit comprised of the aromatic suberin polymer. Comparative post-harvest experiments with different storage temperatures revealed that sikkimensis fruit are more resilient to chilling injuries arise during cold storage, exhibiting lower rates of weight losses, ethylene and CO 2 , electrolyte leakage and lipid peroxidation. We further demonstrate that different storage temperatures affect the contents of skin polymers cutin and suberin in a differential manner. [Display omitted] • The skin of the common cucumber fruit is made of cutin building blocks. • The Sikkim cucumber forms a suberized wound-periderm tissue below its cracked-skin. • The Sikkim cucumber exhibits resilience to chilling injuries during cold storage. • Post-harvest storage temperature affects cucumber fruit skin chemistry. • Cucumber fruit skin polymers play key roles in modulating post-harvest quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • A formulation for biopesticides with UV protection capability has been developed. • The formulation is based on single conidium encapsulation in Pickering emulsion. • Paraffin-in-water emulsions stabilized by TiO 2 -NH 2 particles were developed. • Individual encapsulation of conidia in O/W Pickering emulsion has been confirmed. • Bioassay shows that the formulations give clear UV protection for the conidia. A new formulation for biological pest control with significant UV protection capability has been developed in this research. The formulation is based on individual encapsulation of fungal conidia in an oil/water Pickering emulsion. The droplets size of the emulsions was tuned to meet the demands of single conidia encapsulation in the oil droplets. The emulsions are stabilized by amine-functionalized TiO 2 (titania) nanoparticles (NPs). The droplet size, stability, and structure of the emulsions were investigated at different TiO 2 contents and oil/water phase ratios. Most of the emulsions remained stable for 6 months. The structural properties of the Pickering emulsions were characterized by confocal microscopy and high-resolution cryogenic scanning electron microscopy (cryo-HRSEM). The presence of the TiO 2 particles at the interface was confirmed by both confocal microscopy and cryo-HRSEM. Metarhizium brunneum-7 (Mb7) conidia were added to the emulsions. The successful encapsulation of individual conidia in the oil droplets was confirmed by confocal microscopy. The individual encapsulation of the conidia in the emulsions was significantly improved by dispersing the conidia in a 0.02 % Triton X-100 solution prior to emulsification. In addition, the bioassay results have shown, that exposure of the encapsulated conidia to natural UV light did not change their germination rates, however, the unprotected conidia demonstrated a dramatic decrease in their germination rates. These results confirm the UV protection capability of the studied emulsions. [ABSTRACT FROM AUTHOR]