Programmable Invisible Photonic Patterns with Rapid Response Based on Two-Dimensional Colloidal Crystals

The development of invisible patterns via programmable patterning can lead to promising applications in optical encryption. This study reports a facile method for building responsive photonic crystal patterns. Commercially printed patterns were used as a mask to induce invisible patterns revealed by wetting. The masked areas exhibit different swelling kinetics, leading to strong structural colors in the masked area and transparent features in the unmasked area. The contrast could disappear through different wetting behavior, providing a unique and reversible wetting feature. This programmable printing is expected to become an environmentally friendly technique for scalable invisible optical anti-counterfeiting technology

Transcriptome Analysis Reveals Candidate Lignin-Related Genes and Transcription Factors during Fruit Development in Pomelo (Citrus maxima)

Juice sac granulation (a physiological disorder) leads to large postharvest losses of pomelo (Citrus maxima). Previous studies have shown that juice sac granulation is closely related to lignin accumulation, while the molecular mechanisms underlying this disorder remain elusive in pomelo. Our results showed that the lignin content in NC (near the core) and FC (far away from the core) juice sacs overall increased from 157 DPA (days post anthesis) to 212 DPA and reached a maximum at 212 DPA. Additionally, the lignin content of NC juice sacs was higher than that of FC juice sacs. In this study, we used transcriptome-based weighted gene co-expression network analysis (WGCNA) to address how lignin formation in NC and FC juice sacs is generated during the development of pomelo. After data assembly and bioinformatic analysis, we found a most correlated module (black module) to the lignin content, then we used the 11 DEGs in this module as hub genes for lignin biosynthesis. Among these DEGs, PAL (phenylalanine ammonia lyase), HCT (hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase), 4CL2 (4-coumarate: CoA ligase), C4H (cinnamate 4-hydroxylase), C3′H (p-coumarate 3-hydroxylase), and CCoAOMT1 (caffeoyl CoA 3-Omethyltransferase) were the most distinct DEGs in granulated juice sacs. Co-expression analysis revealed that the expression patterns of several transcription factors such as MYB, NAC, OFP6, and bHLH130 are highly correlated with lignin formation. In addition, the expression patterns of the DEGs related to lignin biosynthesis and transcription factors were validated by qRT-PCR, and the results were highly concordant with the RNA-seq results. These results would be beneficial for further studies on the molecular mechanism of lignin accumulation in pomelo juice sacs and would help with citrus breeding

High-Barrier Oxidized Cellulose Nanofibril/Chitosan Coating for Functional Food Packaging Materials

With the continuous introduction of plastic restriction policies by the government and the continuous enhancement of people’s awareness of environmental protection, the demand for food packaging materials has also continued to increase, and the research and development of biodegradable green packaging materials has become the frontier research direction in the field of food packaging materials. In this study, nanocellulose-based coating solution with high barrier properties was prepared from oxidized cellulose nanofibrils (OCNFs) via sodium periodate and compounded with chitosan solution (CTS) and then coated on the substrate paper. Experiments have found that when the mass fraction of the OCNF in the OCNF/CTS coating solution is 0.5%, the coated paper exhibits the optimum comprehensive performance. The oxygen transmission rate of the OCNF/CTS-coated paper dropped to 1.732 × 10–11 cm3·cm/cm2·s·Pa, and the water vapor transmission rate reduced to 2.236 × 10–12 g·cm/cm2·s·Pa. This is due to the fact that the OCNF cross-linking with CTS improves the compactness of the paper surface layer, which in turn enhances its barrier. These findings suggested that the OCNF/CTS-coated paper has great potential and prospect in the application of food packaging materials, which provide a possible positive example of barrier coating in the packaging field