Invasion and Defense Interactions between Enzyme‐Active Liquid Coacervate Protocells and Living Cells

Abstract

The design and construction of mutual interaction models between artificial microsystems and living cells have the potential to open a wide range of novel applications in biomedical and biomimetic technologies. In this study, an artificial form of invasion‐defense mutual interactions is established in a community of glucose oxidase (GOx)‐containing liquid coacervate microdroplets and living cells, which interact via enzyme‐mediated reactive oxygen species (ROS) damage. The enzyme‐containing coacervate microdroplets, formed via liquid–liquid phase separation, act as invader protocells to electrostatically bind with the host HepG2 cell, resulting in assimilation. Subsequently, the glucose oxidation in the liquid coacervates initiates the generation of H2O2, which serves as an ROS resource to block cell proliferation. As a defense strategy, introduction of catalase (CAT) into the host cells is exploited to resist the ROS damage. CAT‐mediated decomposition of H2O2 leads to the ROS scavenging and results in the recovery of cell viability. The results obtained in the current study highlight the remarkable opportunities for the development of mutual interacting communities on the interface of artificial protocells/living cells. They also provide a new approach for engineering cellular behaviors through exploiting artificial nonliving microsystems.

Giant Coacervate Vesicles As an Integrated Approach to Cytomimetic Modeling

“…1,2 Protocells can be assembled from lipids (vesicles), 3 amphiphilic block copolymers (polymersomes), 4,5 inorganic nanoparticles (colloidosomes), 6,7 protein-polymer nano-conjugates (proteinosomes), 8,9 and polyelectrolytes undergoing liquidliquid microphase separation (coacervation). [10][11][12][13][14][15] Amongst these possibilities, lipid vesicles have been used extensively for studying membrane transport, 16 macromolecular loading, 17 DNA transcription, 18 protein expression, 19 molecular signaling 20 and the origin of life. 21 Giant unilamellar vesicles (GUVs) are often employed as a cytomimetic model system due to the ease of tailoring the composition and structure of their phospholipid bilayer membrane as well as their size, shape, growth, fusion and attendant mechanical/chemical properties.…”

“…Protocells are encapsulated soft microsystems capable of diverse biomimetic functions such as molecular compartmentalization, in vitro gene expression, and proto-metabolism and are therefore of special interest in studies on the origin of life, development of embodied constructs in synthetic biology, and fabrication of small-scale devices in bioengineering and biomedicine. , Protocells can be assembled from lipids (vesicles), amphiphilic block copolymers (polymersomes), , inorganic nanoparticles (colloidosomes), , protein–polymer nanoconjugates (proteinosomes), , and polyelectrolytes undergoing liquid–liquid microphase separation (coacervation). − Among these possibilities, lipid vesicles have been used extensively for studying membrane transport, macromolecular loading, DNA transcription, protein expression, molecular signaling, and the origin of life …”

Construction of Magnetic Nanochains to Achieve Magnetic Energy Coupling in Scaffold

“…To investigate the cells viability induced by the PLLA, PLLA/Fe 3 O 4 and PLLA/Fe 3 O 4 @SiO 2 scaffolds, the cells were strained with calcein AM. Normally, calcein AM only stains living cells, because calcein AM as a dye can be transformed into a membrane impermeable uorescent analogue by the cell esterases, and the uorescence will leak out when the cell membrane is completely damaged [40,41]. As shown in Fig.…”

Engineering of Biocompatible Coacervate-Based Synthetic Cells

“…The relatively straightforward process of mixing oppositely charged polyelectrolytes has given rise to a broad range of materials that are being utilized for complex coacervation. These materials include polyanions (e.g., RNA, ATP, hyaluronic acid, and heparin) and polycations (e.g., diethylaminoethyl (DEAE) dextran, poly­(ethylene argininylaspartate diglyceride) (PEAD), and poly- l -lysine (PLL) , ). However, not all of these materials are appropriate for cocultivation with biological cells, mostly due to their high charge .…”