Shubin Li’s research while affiliated with Harbin Institute of Technology and other places

Constructing a synthetic community system helps scientist understand the complex interactions among species in a community and its environment. Herein, a two-species community is constructed with species A (artificial cells encapsulating pH-responsive molecules and sucrose) and species B (Saccharomyces cerevisiae), which causes the environment to exhibit pH oscillation behaviour due to the generation and dissipation of CO2. In addition, a three-species community is constructed with species A′ (artificial cells containing sucrose and G6P), species B, and species C (artificial cells containing NAD⁺ and G6PDH). The solution pH oscillation regulates the periodical release of G6P from species A′; G6P then enters species C to promote the metabolic reaction that converts NAD⁺ to NADH. The location of species A′ and B determines the metabolism behaviour in species C in the spatially coded three-species communities with CA′B, CBA′, and A′CB patterns. The proposed synthetic community system provides a foundation to construct a more complicated microecosystem.

The bottom‐up constructed artificial cells help to understand the cell working mechanism and provide the evolution clues for organisms. The energy supply and metabolism mimicry are the key issues in the field of artificial cells. Herein, an artificial cell containing cyanobacteria capable of light harvesting and carbon dioxide fixation is demonstrated to produce glucose molecules by converting light energy into chemical energy. Two downstream “metabolic” pathways starting from glucose molecules are investigated. One involves enzyme cascade reaction to produce H2O2 (assisted by glucose oxidase) first, followed by converting Amplex red to resorufin (assisted by horseradish peroxidase). The other pathway is more biologically relevant. Glucose molecules are dehydrogenated to transfer hydrogens to nicotinamide adenine dinucleotide (NAD⁺) for the production of nicotinamide adenine dinucleotide hydride (NADH) molecules in the presence of glucose dehydrogenase. Further, NADH molecules are oxidized into NAD⁺ by pyruvate catalyzed by lactate dehydrogenase, meanwhile, lactate is obtained. Therefore, the cascade cycling of NADH/NAD⁺ is built. The artificial cells built here pave the way for investigating more complicated energy‐supplied metabolism inside artificial cells.

The bottom-up constructed artificial cells help to understand the cell working mechanism and provide the evolution clues for organisms. Cyanobacteria are believed to be the ancestors of chloroplasts according to endosymbiosis theory. Herein we demonstrate an artificial cell containing cyanobacteria to mimic endosymbiosis phenomenon. The cyanobacteria sustainably produce glucose molecules by converting light energy into chemical energy. Two downstream "metabolic" pathways starting from glucose molecules are investigated. One involves enzyme cascade reaction to produce H2O2 (assisted by glucose oxidase) first, followed by converting Amplex red to resorufin (assisted by horseradish peroxidase). The more biological one involves nicotinamide adenine dinucleotide (NADH) production in the presence of NAD+ and glucose dehydrogenase. Further, NADH molecules are oxidized into NAD+ by pyruvate catalyzed by lactate dehydrogenase, meanwhile, lactate is obtained. Therefore, the sustainable cascade cycling of NADH/NAD+ is built. The artificial cells built here simulate the endosymbiosis phenomenon, meanwhile pave the way for investigating more complicated sustainable energy supplied metabolism inside artificial cells.

In nature, cells self-assemble into spatially coded tissular configurations to execute higher-order biological functions as a collective. This mechanism has stimulated the recent trend in synthetic biology to construct tissue-like assemblies from protocell entities, with the aim to understand the evolution mechanism of multicellular mechanisms, create smart materials or devices, and engineer tissue-like biomedical implant. However, the formation of spatially coded and communicating micro-architectures from large quantity of protocell entities, especially for lipid vesicle-based systems that mostly resemble cells, is still challenging. Herein, we magnetically assemble giant unilamellar vesicles (GUVs) or cells into various microstructures with spatially coded configurations and spatialized cascade biochemical reactions using a stainless steel mesh. GUVs in these tissue-like aggregates exhibit uncustomary osmotic stability that cannot be achieved by individual GUVs suspensions. This work provides a versatile and cost-effective strategy to form robust tissue-mimics and indicates a possible superiority of protocell colonies to individual protocells. To execute higher-order functions, cells self-assemble into spatially coded tissue configurations. Here the authors magnetically assembly giant unilamellar vesicles into three dimensional tissue-mimic structures with collective osmotic stability.

The asymmetric micro/nano motors have attracted great attentions recently, because they convert external physical and chemical energy into the kinetic energy. Red blood cell (RBC) membranes with good deformability and fluidity are excellent natural templates for micromaterial fabrication. Herein, RBC membranes were used as templates to prepare bowl‐like micro‐motors by electroless plating platinum particle onto the membranes. The asymmetric Pt bowl‐like micromotors were driven by hydrogen peroxide.

The chemical signal communication among organelles in the cell is extremely important for life. We hereby demonstrated that the chemical signal communication between two protoorganelles using cascade enzyme reactions in a lipid based artificial cell. Two protoorganelles inside the artificial cell are the large unilamellar vesicles containing glucose oxidase (GOx-LUVs) and the vesicle containing (horseradish peroxidase (HRP) and Amplex red), respectively. The glucose molecules outside the artificial cell penetrate the lipid bilayer through mellitin pores and enter into one protoroganelle (GOx-LUVs) to produce H2O2, which subsequently transport to the other protoorganelle to oxidize Amplex red into red resorufin catalyzed by HRP. The number of GOx-LUVs in an artificial cell is controlled by using GOx-LUVs solution with different density during the electroformation. The reaction rate for resorufin in the protoorganelle increases with more GOx-LUVs inside the artificial cell. The artificial cell developed here paves the way for more complicated signal transduction mechanism study in a eukaryocyte.

Dyestuffs and heavy metal ions in water are seriously harmful to the ecological environment and human health. Three-dimensional (3D) flowerlike Fe(OH)3 microspheres were synthesized through a green yet low-cost injection method, for the removal of organic dyes and heavy metal ions. The Fe(OH)3 microspheres were characterized by thermal gravimetric analysis (TGA), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM) techniques. The adsorption kinetics of Congo Red (CR) on Fe(OH)3 microspheres obeyed the pseudo-second-order model. Cr⁶⁺ and Pb²⁺ adsorption behaviors on Fe(OH)3 microspheres followed the Langmuir isotherm model. The maximum adsorption capacities of the synthesized Fe(OH)3 were 308, 52.94, and 75.64mg/g for CR, Cr⁶⁺, and Pb²⁺ respectively. The enhanced adsorption performance originated from its surface properties and large specific surface area of 250m²/g. The microspheres also have excellent adsorption stability and recyclability. Another merit of the Fe(OH)3 material is that it also acts as a Fenton-like catalyst. These twin functionalities (both as adsorbent and Fenton-like catalyst) give the synthesized Fe(OH)3 microspheres great potential in the field of water treatment.