Light-Harvesting in Biophotonic Optofluidic Microcavities via Whispering-Gallery Modes

Molecular mechanisms underlying sodium percarbonate treatment suppress the recovery and growth of Pseudanabaena sp. in early spring

Increasing frequency and intensity of cyanobacterial blooms in water sources is a growing global issue. Algicides are usually implemented in summer or autumn when blooms break out, however, the blooms will form again when algicide's concentration declines to a certain extent. Preventing the recovery and growth of cyanobacteria in early spring may be conducive to abatement of the blooms in summer or autumn. In this study solid sodium percarbonate (SPC) was used as an algicide to suppress recovery and growth of Pseudanabaena sp., a common odour-producing cyanobacterium, in early spring (12 °C). Results showed that 3.0 and 6.0 mg/L SPC were able to kill most of the algal cells after 12 h treatment at 12 °C, and the residual cells gradually died during the re-cultivation period at 25 °C. As a control, although SPC also caused most of algal cells to lyse at 25 °C, regrowth of cells was found during the period of re-cultivation at 25 °C. Transcriptomic analysis revealed that the dysregulated genes were strongly associated with translation and photosynthesis after SPC treatment. All differentially expressed unigenes related to translation and photosynthesis were down-regulated after SPC oxidation at 12 °C, whereas key genes associated with translation and photosynthesis were upregulated after SPC treatment at 25 °C.

Single-layer semiconductor-decorated flexible 2D protein nanosheets by engineered anchoring for efficient photocatalytic hydrogen production

Protein self-assembly can be accurately manipulated to form ordered nanostructures through various supramolecular forces. This strategy is expected to make significant breakthroughs in the field of new biomimetic functional materials. Specifically, the construction of photocatalytic systems on two-dimensional (2D) flexible protein nanosheets meets a great challenge. We introduce a synthetic methodology for creating single-layer semiconductor-decorated protein 2D materials under mild conditions with enhanced light-driven hydrogen production. This approach employs a bioengineered green fluorescent protein (E4P) with the addition of a Cd-binding peptide, enabling precise control of the assembly of CdS quantum dots (QDs) on the protein's surface. Consequently, we obtained 4.3 nm-thin single-layer 2D protein nanosheets with substantial surface areas ideal for accommodating CdS QDs. By orthogonal incorporation of metal-binding peptides and supramolecular coordination, significantly enhancing the overall photocatalytic efficiency. Our findings demonstrate the potential for stable and efficient hydrogen production, highlighting the adaptability and biocompatibility of protein scaffolds for photocatalysis.

Harsh temperature induces Microcystis aeruginosa growth enhancement and water deterioration during vernalization

Cyanobacterial blooms are seasonal phenomena in eutrophic water. Cyanobacteria grow fast in the warm spring/summer while disappearing in cold autumn/winter. The temperature change induces algal vernalization. However, whether vernalization affects cyanobacterial blooms, and the regulatory signaling mechanisms are unclear. This study used Microcystis aeruginosa as the model cyanobacteria, and 4 °C and 10 °C as the low-temperature stimulation to explore the cell growth, metabolites, and signaling pathways in cyanobacteria vernalization. Low temperatures induced M. aeruginosa vernalization; the growth rate and cell density increased by 35±4% and 33±2%. Vernalization influenced peptidoglycan synthesis and cell permeability. Soluble microbial products (SMPs) in water increased by 109±5%, resulting in water deterioration. Polysaccharides were the predominant SMPs during the initial term of vernalization. Tryptophan protein-like & humic acid-like substances became the main increased SMPs in the middle-later period of vernalization. Harsh temperatures triggered quorum sensing and two-component system. Signaling sensing systems upregulated photosynthesis, glycolysis, TCA cycle, oxidative phosphorylation, and DNA replication, enhancing M. aeruginosa growth and metabolism during vernalization. This study verified that low temperature stimulates cyanobacteria growth and metabolism, and vernalization possibly aggravates cyanobacterial blooms and water deterioration. It provides new insights into the mechanism of seasonal cyanobacterial blooms and the pivotal role of signaling regulation.

Liquid Crystal Biosensors: Principles, Structure and Applications

Liquid crystals (LCs) have been widely used as sensitive elements to construct LC biosensors based on the principle that specific bonding events between biomolecules can affect the orientation of LC molecules. On the basis of the sensing interface of LC molecules, LC biosensors can be classified into three types: LC-solid interface sensing platforms, LC-aqueous interface sensing platforms, and LC-droplet interface sensing platforms. In addition, as a signal amplification method, the combination of LCs and whispering gallery mode (WGM) optical microcavities can provide higher detection sensitivity due to the extremely high quality factor and the small mode volume of the WGM optical microcavity, which enhances the interaction between the light field and biotargets. In this review, we present an overview of the basic principles, the structure, and the applications of LC biosensors. We discuss the important properties of LC and the principle of LC biosensors. The different geometries of LCs in the biosensing systems as well as their applications in the biological detection are then described. The fabrication and the application of the LC-based WGM microcavity optofluidic sensor in the biological detection are also introduced. Finally, challenges and potential research opportunities in the development of LC-based biosensors are discussed.