Construction of spidroin coacervate microdroplets and regulation of their morphology.

In recent years, developing artificial cells of higher complexity has emerged as being key to simulating advanced life behaviors, among which coacervate microdroplets are a promising kind of model artificial cell. Constructing simple coacervate systems in vitro which can subsequently achieve specific responses to environmental stimuli to form coacervate microdroplet communities are fundamental for studying the interactions between liquid-liquid phase separated molecules and the way such interactions determine material properties, composition and phase behavior. Herein, we propose a membrane-free artificial cell based on recombinant spidroin, NT2RepCT, which utilizes the complex structure of spidroin to provide coacervate microdroplets with a unique population morphology in response to environmental stimuli. By changing the environmental conditions such as protein concentration, pH and temperature, the coacervate microdroplets of single-type, regular adhesion-type and irregular adhesion-type were statistically generalized, and it is highlighted that the adhesion-type of coacervate microdroplets depended on the α-helical percentage, complex folding degree of spidroin and internally hydrophobic environment of the coacervate, while it was inversely proportional to the surface hydrophobic environment. Much more interesting, regulation of the non-enzymatic polymerization reaction of oligonucleotides was successfully achieved by adjusting the population morphology of coacervate microdroplets.

Photosynthesis-Mediated Intracellular Biomineralization of Gold Nanoparticles inside Chlorella Cells towards Hydrogen Boosting under Green Light.

Engineering living microorganisms to enhance green biomanufacturing for the development of sustainable and carbon-neutral energy strategies has attracted the interest of researchers from a wide range of scientific communities. In this study, we develop a method to achieve photosynthesis-mediated biomineralization of gold nanoparticles (AuNPs) inside Chlorella cells, where the photosynthesis-dominated reduction of Au3+ to Au0 allows the formed AuNPs to locate preferentially around the thylakoid membrane domain. In particular, we reveal that the electrons generated by the localized surface plasmon resonance of AuNPs could greatly augment hypoxic photosynthesis, which then promotes the generation and transferring of photoelectrons throughout the photosynthetic chain for augmented hydrogen production under sunlight. We demonstrate that the electrons from AuNPs could be directly transferred to hydrogenase, giving rise to an 8.3-fold enhancement of Chlorella cells hydrogen production independent of the cellular photosynthetic process under monochromatic 560 nm light irradiation. Overall, the photosynthesis-mediated intracellular biomineralization of AuNPs could contribute to a novel paradigm for functionalizing Chlorella cells to augment biomanufacturing.