Rapid Growth and Fusion of Protocells in Surface‐Adhered Membrane Networks

Elevated temperatures might have promoted the nucleation, growth, and replication of protocells on the early Earth. Recent reports have shown evidence that moderately high temperatures not only permit protocell assembly at the origin of life, but can have actively supported it. Here, the fast nucleation and growth of vesicular compartments from autonomously formed lipid networks on solid surfaces, induced by a moderate increase in temperature, are shown. Branches of the networks, initially consisting of self‐assembled interconnected nanotubes, rapidly swell into microcompartments which can spontaneously encapsulate RNA fragments. The increase in temperature further causes fusion of adjacent network‐connected compartments, resulting in the redistribution of the RNA. The experimental observations and the mathematical model indicate that the presence of nanotubular interconnections between protocells facilitates the fusion process.     

How Protocells Can Make ‘Stuff’ Much More Interesting

Rachel Armstrong explains why living systems with their own metabolisms provide more exciting and far-reaching solutions than conventional building materials. She also explicitly explains why the pursuit of protocell technology, which enables us to artificially design living systems, is so much more promising than established methods, such as incorporating high-maintenance biological features – green walls or roofs – into existing urban context or applying biomimicry to traditional materials. Copyright © 2011 John Wiley & Sons, Ltd.     

Biomimicry of Cellular Motility and Communication Based on Synthetic Soft‐Architectures

Cells, sophisticated membrane‐bound units that contain the fundamental molecules of life, provide a precious library for inspiration and motivation for both society and academia. Scientists from various disciplines have made great endeavors toward the understanding of the cellular evolution by engineering artificial counterparts (protocells) that mimic or initiate structural or functional cellular aspects. In this regard, several works have discussed possible building blocks, designs, functions, or dynamics that can be applied to achieve this goal. Although great progress has been made, fundamental—yet complex—behaviors such as cellular communication, responsiveness to environmental cues, and motility remain a challenge, yet to be resolved. Herein, recent efforts toward utilizing soft systems for cellular mimicry are summarized—following the main outline of cellular evolution, from basic compartmentalization, and biological reactions for energy production, to motility and communicative behaviors between artificial cell communities or between artificial and natural cell communities. Finally, the current challenges and future perspectives in the field are discussed, hoping to inspire more future research and to help the further advancement of this field.     

Soil and Protoplasm: The Hylozoic Ground Project

Housed in the Canadian Pavilion in the Giardini in Venice during the 2010 Architecture Biennale, the Hylozoic Ground project provided visitors with the unique experience of interacting with a responsive and ‘live’ textile matrix. Philip Beesley and Rachel Armstrong describe the extraordinary ‘soil-less’ environment that they collaborated on and how it provides a new model for a synthetic but evolutionary ecology. Copyright © 2011 John Wiley & Sons, Ltd.     

Chemical Information Exchange in Organized Protocells and Natural Cell Assemblies with Controllable Spatial Positions

An ultrasound‐based platform is established to prepare homogenous arrays of giant unilamellar vesicles (GUVs) or red blood cell (RBCs), or hybrid assemblies of GUV/RBCs. Due to different responses to the modulation of the acoustic standing wave pressure field between the GUVs and RBCs, various types of protocell/natural cell hybrid assemblies are prepared with the ability to undergo reversible dynamic reconfigurations from vertical to horizontal alignments, or from 1D to 2D arrangements. A two‐step enzymatic cascade reaction between transmitter glucose oxidase‐containing GUVs and peroxidase‐active receiver RBCs is used to implement chemical signal transduction in the different hybrid micro‐arrays. Taken together, the obtained results suggest that the ultrasound‐based micro‐array technology can be used as an alternative platform to explore chemical communication pathways between protocells and natural cells, providing new opportunities for bottom‐up synthetic biology.     

Coordinated Membrane Fusion of Proteinosomes by Contact‐Induced Hydrogel Self‐Healing

Controlled membrane fusion of proteinosome‐based protocells is achieved via a hydrogel‐mediated process involving dynamic covalent binding, self‐healing, and membrane reconfiguration at the contact interface. The rate of proteinosome fusion is dependent on dynamic Schiff base covalent interchange, and is accelerated in the presence of encapsulated glucose oxidase and glucose, or inhibited with cinnamyl aldehyde due to enzyme‐mediated decreases in pH or competitive covalent binding, respectively. The coordinated fusion of the proteinosomes leads to the concomitant transportation and redistribution of entrapped payloads such as DNA and dextran. Silica colloids with amino‐functionalized surfaces undergo partial fusion with the proteinosomes via a similar dynamic hydrogel‐mediated mechanism. Overall, the strategy provides opportunities for the development of interacting colloidal objects, control of collective behavior in soft matter microcompartmentalized systems, and increased complexity in synthetic protocell communities.