Bacterial cellulose (BC), obtained from fermented food byproducts (Symbiotic Culture of Bacteria and Yeast, and Nata de Coco), was successfully used as a template for the synthesis of a YBa2Cu3O6+δ (YBCO) superconductor. As previous studies have shown, a dry template is needed to ensure the maximum uptake of the precursor solution. BC used is obtained in a wet state; it must be dried before use as a template. A variety of template drying techniques were investigated to assess the efficacy. This included air, oven, freeze, and solvent exchange drying. Among these, freeze-drying proved to be the most effective method as it best preserved the porous internal structure of the template. The addition of ethylenediaminetetraacetic acid (EDTA), a polychelating acid, also had a beneficial effect on the synthesis, improving both phase purity and the contribution of the superconducting phase. Waste-derived BC was shown to be a suitable substrate for the sol-gel synthesis of cuprate superconductors, providing an alternative to the ionic-liquid/nanocellulose-based approach used previously.

Functional porous superconducting sponges, consisting of YBa 2 Cu 3 O 6+ δ (YBCO) and Bi 2 Sr 2 CaCu 2 O 8+ δ (BSCCO), were created by biotemplating with natural sea sponges.

A protocol for the preparation of fatty acid-functionalized nanohydroxyapatite was developed. These nanoparticles were characterized and used as building blocks for the preparation of Pickering water-in-oil emulsions, which in turn were used as a template for colloidosomes. It is possible to encapsulate proteins in these structures, and their low cellular toxicity was also demonstrated. These structures show structural fragility to pH and temperature changes.

The design and implementation of collective actions in model protocell communities is an on-going challenge in synthetic protobiology. Herein, we covalently graft alginate or chitosan onto the outer surface of semipermeable enzyme-containing silica colloidosomes to produce hairy catalytic protocells with pH-switchable membrane surface charge. Binary populations of the enzymatically active protocells exhibit self-initiated stimulus-responsive changes in spatial organization such that the mixed community undergoes alternative modes of electrostatically induced self-sorting and reversible co-clustering. We demonstrate that co-clustering, but not self-sorting, mitigates signal attenuation in a binary community of enzyme-containing sender and receiver protocells due to increased proximity effects. The level of signal attenuation is correlated with a time-dependent pH-mediated switch in the spatial organization of the sender and receiver populations. Our results pave the way towards the development of programmable networks of adaptive life-like objects and could have implications for the development of interactive cytomimetic materials and agent-based robotics.

The construction of biomimetic agents capable of generating precise outcomes in response to specific molecular inputs is a central challenge for the development of programmable synthetic cells with integrated biomimetic functions. Here, we harness acoustic standing waves to generate periodic microarrays of enzyme-encoded coacervate microdroplets for the implementation of embodied enzyme logic circuits (EELCs). We describe a range of biocatalytic communication channels capable of performing localized and distributed Boolean logic functions in single or segregated populations of model protocells by using a range of molecular inputs, fluorescence or hydrogelation outputs, and programmable response dynamics. To implement long-range collective signal processing, we integrate EELC modules across spatially segregated protocell populations to generate distributed time-regulated logic operations involving negative feedback, pulse generation, and redirected output-input connectivity. Our results provide a step toward the non-DNA programming of model protocell communication and computational networks for miniaturized autonomous sensing devices capable of chemical-based information processing.

The design and construction of continuous flow biochemical reactors comprising immobilized biocatalysts have generated great interest in the efficient synthesis of value-added chemicals. Living cells use compartmentalization and reaction-diffusion processes for spatiotemporal regulation of biocatalytic reactions, and implementing these strategies into continuous flow reactors can offer new opportunities in reactor design and application. Herein, the fabrication of protocell-based continuous flow reactors for enzyme and whole-cell mediated biocatalysis is demonstrated. Semipermeable membranized coacervate vesicles are employed as model protocells that spontaneously sequester enzymes or accumulate living bacteria to produce embodied microreactors capable of single- or multiple-step catalytic reactions. By packing millions of the enzyme/bacteria-containing coacervate vesicles in a glass column, a facile, cost-effective, and modular methodology capable of performing oxidoreductase, peroxidase and lipolytic reactions, enzyme-mediated L-DOPA synthesis, and whole-cell glycolysis under continuous flow conditions, is demonstrated. It is shown that the protocell-nested enzymes and bacterial cells exhibit enhanced activities and stability under deleterious operating conditions compared with their non-encapsulated counterparts. These results provide a step toward the engineering of continuous flow reactors based on cell-like microscale agents and offer opportunities in the development of green and sustainable industrial bioprocessing.

Fulminating gold, the first high-explosive compound to be discovered, disintegrates into a mysterious cloud of purple smoke, the nature of which has been speculated upon since its discovery in the 15th century. In this work, we show that the colour of the smoke is due to the presence of gold nanoparticles.

The taxis of microscale objects in response to environmental chemical gradients represents a fundamental step toward the construction and programming of motile cytomimetic agents. Here, we demonstrate that various modes of autonomous oscillatory movement can be implemented across stratified chemical media by sensory -mediated actuation of protocell buoyancy. We use enzyme powered peptide/polynucleotide protocells as microscale agents that sense and move in response to stationary or diffusive chemical fronts present in their local environment. By using stratified sucrose density gradients of antagonistic enzyme substrates, sustainable non -harmonic oscillatory movements, short-lived quasi -harmonic trajectories, damped harmonic behaviors, and states of protocell levitation are implemented under non -equilibrium conditions. Furthermore, transitions from harmonic to damped oscillatory trajectories provide a spatiotemporal mechanism for transient protocell-mediated reactivity and execute protocell logistics using oscillatory cell-like transporter capable of repeated pick-up and delivery of molecular cargo. Our work provides opportunities for the development of soft microrobotics and sensing/delivery microscale agents.

Fulminating gold, the first high-explosive compound to be discovered, disintegrates in a mysterious cloud of purple smoke, the nature of which has been speculated upon since its discovery in 1585. In this work, we show that the colour of the smoke is due to the presence of gold nanoparticles.

A novel aromatic diamine, 2,5-bis-[4"aminobenzyl)-4'-benzamide]-3,4-diphenyl thiophene (BATP) containing bulky tetraphenyl thiophene group, methylene spacer and preformed amide linkage was synthesized and characterized by FT-IR, NMR ( 1 H, 13 C, DEPT 13 C) and Mass spectrometry.A series of novel aromatic poly(amide-azomethine)s was successfully prepared by solution polycondensation of BATP with aromatic dialdehydes, namely isophthalaldehyde (IPA) and / or terephthaldehyde (TPA) in different mole % proportions.All the poly(amide-azomethine)s were characterized by FT-IR spectroscopy, viscosity measurements, solubility tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray diffraction (XRD).The results of characterization shows that these polymers meet high temperature resistant requirements so could find applications as special materials in aerospace, military and microelectronics industries.

The de novo synthesis and self-assembly of molecules to establish the framework of living systems is a key target in the field of systems chemistry. The construction of synthetic cellular systems from scratch is one important such route to achieve this goal. This Special Collection on Protocells and Prebiotic Systems, guest edited by Dora Tang and Avinash J. Patil, showcases some of the most exciting work done in this field today. (D.Tang photograph copyright MPI-CBG). The de novo synthesis of molecules and their self-assembly to establish the framework of living systems is a key goal of systems chemistry. One route to achieving this is by building synthetic cellular systems from scratch which provides a gateway to understand and control emergence that arises from an integration of functional molecules and biological nanostructures at various length scales. Progress in this area can have significant impact for unravelling the origins of life, synthetic biology and future biomedical applications whilst providing fundamental insights into the mechanisms of biological systems. This Special Collection on Protocells and Prebiotic Systems brings together new and exciting work that is taking place in this field and demonstrates the extraordinary breadth of contributions required to make progress in this area: From prebiotic chemistry, to a survey of the molecular parts which can be used to design and build programmable cell-like compartments, engineer catalytic microreactors or create higher ordered architectures, to the emergence of adaptable systems where chemical environments can tune the physicochemical properties of soft materials. Furthermore, the capability to assimilate these properties to mimic fundamental biological processes such as chemical signaling; motility; energy transduction or cell growth and division are ever increasing. Whilst these examples are crucial for establishing minimal living systems, there are exciting prospects to exploit synthetic-cell-like compartments in wide-ranging applications including biomimetic materials; novel stimuli-responsive delivery platforms; biocatalysis; environmental remediation; tissue engineering; regenerative medicine; living materials and in adaptive integration to biological cells. The opinions expressed in this publication are the view of the author(s) and do not necessarily reflect the opinions or views of ChemSystemsChem, the Publisher, Chemistry Europe, or the affiliated editors. Dora Tang is currently a research group leader at the MPI-CBG, Dresden (Germany). Her multidisciplinary lab reimagines and translates the physical phenemona which drive out of equilibrium processes in cells to novel, robust and dynamic synthetic cellular systems. The minimal systems address questions in origin of life and modern biology. (Photograph copyright MPI-CBG). Avinash J. Patil is a faculty and group leader at the Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol (UK). His research interests cover the design and construction of artificial cells, smart microreactors, and functional hybrid nanomaterials by combining various aspects of biology, materials chemistry, and micro/nanofabrication techniques.

Recent progress in the literature has shown that polymers play a significant role in the green synthesis of metal nanoparticles (MNPs) utilized in the biomedical and pharmaceutical fields. Exceptional characteristics, such as biocompatibility and nontoxicity of the polymers (natural and fewer synthetic), promote their use not just for controlling the particle size, but also for stabilizing the formed MNPs. Polymer-stabilized MNPs exhibit significant superior properties in comparison to their bulk materials and pristine MNP counterparts. The rationale of this chapter is to review the polymers that are employed during the preparation of MNPs, which demonstrate encouraging potential for wound-dressing and anticancer applications. This chapter offers collective information on the polymer-supported nanoparticles or composite derivatives that have been obtained by various synthetic routes. Furthermore, this chapter emphasizes the strategies involved and the role of polymeric materials with nucleating agents, which control the shape and size of NPs. Finally, the potential applications of such nanomaterials, exclusively examined for wound-dressing and anticancer applications, are summarized.

Molecularly crowded coacervate micro-droplets are useful protocell constructs but the absence of a physical membrane limits their application as cytomimetic models. Auxiliary surface-active agents have been harnessed to stabilize the coacervate droplets by irreversible shell formation but endogenous processes of reversible membranization have received minimal attention. Herein, we describe a dynamic alginate/silk coacervate-based protocell model in which membrane-less droplets are reversibly reconfigured and inflated into semipermeable coacervate vesicles by spontaneous self-organization of amphiphilic silk polymers at the droplet surface under non-neutral charge conditions in the absence of auxiliary agents. We show that membranization can be reversibly controlled endogenously by programming the pH within the protocells using an antagonistic enzyme system such that structural reconfigurations in the protocell microstructure are coupled to the trafficking of water-soluble solutes. Our results open new perspectives in the design of hybrid protocell models with dynamical structural properties.

The ability to assemble chemically different gelator molecules into complex supramolecular hydrogels provides excellent opportunities to construct functional soft materials. Herein, we demonstrate the formation of hybrid nucleotide–amino acid supramolecular hydrogels. These are generated by the silver ion (Ag+)-triggered formation of silver–guanosine monophosphate (GMP) dimers, which undergo self-assembly through non-covalent interactions to produce nanofilaments. This process results in a concomitant pH reduction due to the abstraction of a proton from the guanine residue, which triggers the in situ gelation of a pH-sensitive amino acid, N-fluorenylmethyloxycarbonyl tyrosine (FY), to form nucleotide–amino acid hybrid hydrogels. Alterations in the supramolecular structures due to changes in the assembly process are observed, with the molar ratio of Ag:GMP:FY affecting the assembly kinetics, and the resulting supramolecular organisation and mechanical properties of the hydrogels. Higher Ag:GMP stoichiometries result in almost instantaneous gelation with non-orthogonal assembly of the gelators, while at lower molar ratios, orthogonal assembly is observed. Significantly, by increasing the pH as an external stimulus, nanofilaments comprising FY can be selectively disassembled from the hybrid hydrogels. Our results demonstrate a simple approach for the construction of multicomponent stimuli-responsive supramolecular hydrogels with adaptable network and mechanical properties.

Artificial cell-like communities participate in diverse modes of chemical interaction but exhibit minimal interfacing with their local environment. Here we develop an interactive microsystem based on the immobilization of a population of enzyme-active semipermeable proteinosomes within a helical hydrogel filament to implement signal-induced movement. We attach large single-polynucleotide/peptide microcapsules at one or both ends of the helical protocell filament to produce free-standing soft microactuators that sense and process chemical signals to perform mechanical work. Different modes of translocation are achieved by synergistic or antagonistic enzyme reactions located within the helical connector or inside the attached microcapsule loads. Mounting the microactuators on a ratchet-like surface produces a directional push-pull movement. Our methodology opens up a route to protocell-based chemical systems capable of utilizing mechanical work and provides a step towards the engineering of soft microscale objects with increased levels of operational autonomy.

The development of programmable microscale materials with cell-like functions, dynamics and collective behaviour is an important milestone in systems chemistry, soft matter bioengineering and synthetic protobiology. Here, polymer/nucleotide coacervate micro-droplets are reconfigured into membrane-bounded polyoxometalate coacervate vesicles (PCVs) in the presence of a bio-inspired Ru-based polyoxometalate catalyst to produce synzyme protocells (Ru 4 PCVs) with catalase-like activity. We exploit the synthetic protocells for the implementation of multi-compartmentalized cell-like models capable of collective synzyme-mediated buoyancy, parallel catalytic processing in individual horseradish peroxidase-containing Ru 4 PCVs, and chemical signalling in distributed or encapsulated multi-catalytic protocell communities. Our results highlight a new type of catalytic micro-compartment with multi-functional activity and provide a step towards the development of protocell reaction networks.

Introduction: In the current study, we investigate the effect of the inflammation occupying the apical foramen - a phenomenon we refer to as "inflammatory plug" - on the regenerative potential of a root canal therapy. Methods: We performed root canal treatment (RCT) in 12 canine root canals while aseptically instrumenting the apex to a 0.5-mm-wide foramen and obturating the canals with the following materials: collagen sponge, platelet-rich fibrin, and blood clot (no material introduced). Results: We were successful in maintaining the integrity of the periapical tissue in 8 of 12 RCTs. Injury to the periapical tissue occurred during the remaining 4 RCTs, which initiated inflammation accompanied by bone and dentin resorption. Our histologic analyses showed that the resulting inflammatory plug contained abundant M1 macrophages and was associated with an absence of intracanal cellular infiltration. On the contrary, noninflamed samples showed signs of repair, as indicated by the migration of periapical cells throughout the root canal. Conclusions: We conclude that controlling periapical inflammation is key while attempting to achieve dental pulp regeneration.

Compartmentalized protocell objects immobilized in 3D hydrogels provide a step towards the modular assembly of soft functional materials. In their Research Article on page 6853, J. Liu, M. Li, S. Mann, and co-workers present the development of modular hydrogel-based microreactor assemblies comprising millions of polysaccharide–polynucleotide coacervate droplets. An input/output module was used to implement a UV-induced cascade reaction with a spatiotemporal fluorescence read-out.

Immobilization of compartmentalized microscale objects in 3D hydrogels provides a step towards the modular assembly of soft functional materials with tunable architectures and distributed functionalities. Herein, we report the use of a combination of micro-compartmentalization, immobilization, and modularization to fabricate and assemble hydrogel-based microreactor assemblies comprising millions of functionalized polysaccharide-polynucleotide coacervate droplets. The heterogeneous hydrogels can be structurally fused by interfacial crosslinking and coupled as input and output modules to implement a UV-induced photocatalytic/peroxidation nanoparticle/DNAzyme reaction cascade that generates a spatiotemporal fluorescence read-out depending on the droplet number density, intensity of photoenergization, and chemical flux. Our approach offers a route to heterogeneous hydrogels with endogenous reactivity and reconfigurable architecture, and provides a step towards the development of soft modular materials with programmable functionality.

The design and assembly of artificial protocell consortia displaying dynamical behaviours and systems-based properties are emerging challenges in bottom-up synthetic biology. Cellular processes such as morphogenesis and differentiation rely in part on reaction-diffusion gradients, and the ability to mimic rudimentary aspects of these non-equilibrium processes in communities of artificial cells could provide a step to life-like systems capable of complex spatiotemporal transformations. Here we expose acoustically formed arrays of initially identical coacervate micro-droplets to uni-directional or counter-directional reaction-diffusion gradients of artificial morphogens to induce morphological differentiation and spatial patterning in single populations of model protocells. Dynamic reconfiguration of the droplets in the morphogen gradients produces a diversity of membrane-bounded vesicles that are spontaneously segregated into multimodal populations with differentiated enzyme activities. Our results highlight the opportunities for constructing protocell arrays with graded structure and functionality and provide a step towards the development of artificial cell platforms capable of multiple operations.