Non-living Matter Research Articles

Molecular foundations for shear-induced dynamics of natural organic matter.

The overall objective of the present work was to quantify how shear, coupled with varying salt concentration, affected the particle size distribution and relaxation/aggregation behavior for various organic sources of nonliving natural organic matter (NNOM) in surface water. NNOM has been implicated as a conditioning agent leading to the formation of biofilms such as algae. NNOM is also a responsible in surface waters for facilitated transport of a variety of anthropogenic pollutants. These are NNOM surface-related phenomena, yet the variable surface area and surface composition of NNOM, which can change dependent on shear rate, is not discussed in the literature. NNOM polymer-like dynamics can interact with stream water velocity differences to determine the process and result of aggregation. The fundamental role of post-shear NNOM molecular structure and dynamic aggregation (self-assembly) is examined here alongside fresh (hydrological) versus mined (terrestrial) NNOM. Shear rate can be seen as a change in the velocities of streamlines in hydrology. In this early work, the response to shear rate for three types of NNOM was measured using a stress-controlled rheometer under varying conditions of ionic strength. Samples were studied for rheological response after a variety of pre-shear conditions, and data then coupled with surface composition data from previously reported fluorescence studies. Interestingly, a size class of 5μm aggregates disappeared when Aldrich humic acid samples were treated with 0.3M Ca2+. Evidence is also presented that the environmental samples flocculated at shear rates up to 400s-1, rather than exhibiting particle breakup, with implications for reducing NNOM surface area. Dynamic response of different NNOM sources was not the same, some sources showing evidence of self-assembly. The molecular response to shear may play an important role in understanding the surface area and composition of NNOM responsible for facilitated transport of pollutants and initiation of biofilms.

Optogenetic Engineered Living Materials.

Engineered living materials (ELM) is a new frontier in materials research that uses living microorganisms to augment nonliving materials with lifelike capabilities, such as responding to external stimuli. This is achieved by genetically programming the microorganisms in an ELM with stimulus-sensing modules. A popular stimulus to remotely control various ELM functions is light, which has been realized thanks to optogenetics. This chapter describes methods to create a simple ELM capable of sensing light and responding to it by producing and releasing a drug. The material component of the ELM will be a Pluronic F127-based hydrogel and the living component will be optogenetically engineered bacteria. Such ELMs are being developed to create smart therapeutic solutions for challenging chronic diseases and variations in the design to improve performance and safety will be mentioned.

In-vitro Cell Culture: A Promising Technology in the Advancement of Science and Research as a Solution to Human and Animal Health Issues

From ancient Romans till late nineties, conceptualized first by Aristotle, it was believed that life evolved from non-living matter, the spontaneous generation theory. With the invention of microscopy, invisible life was for the first time visible as “animalcules”, that were later described as cells and the cell theory and theory of tissue formation came into limelight. In late nineties cell culture methods were discussed and in-vivo as well as in-vitro cell culture was achieved. In-vitro cell culture techniques were defined, improved, augmented and refined with the advancement in biological sciences. The applications of cell culture technology spanned through various fields, in pathology, microbiology, reproduction, physiology and production of biologicals, monoclonal antibodies, vaccines. In-vitro fertilization, embryo splitting and transgene delivery for augmenting fertility in human and animals, production of animal products, key biomolecules, proteins are some of the endowed applications of in-vitro cell culture technique. Cell culture technology has taken leaps and has become a key modelling system for large class of biotechnological interventions, clinical and industrial applications. Production of important hormones, growth factors, biomolecules and therapeutic agents are all blessings of in-vitro cell culture technology. In-vitro cell culture technology has entered into new era of development of organoids, organ chips, RNA/ DNA / recombinant vaccines, transgenic animals, tissue reconstructs etc. in pursuit of achieving better health care and food security. In-vitro cell culture technology has been playing a significant role in the global economy with huge market size in stem cell therapy, human infertility and production of therapeutic biomolecules. The in-vitro cell culture technology is promising, fast evolving, robust and matured technology with huge potential to revolutionize the fields of medicine, biological sciences and biomedical-engineering.

Role of Humic Substances in the (Bio)Degradation of Synthetic Polymers under Environmental Conditions

Information on the detection of the presence and potential for degradation of synthetic polymers (SPs) under various environmental conditions is of increasing interest and concern to a wide range of specialists. At this stage, there is a need to understand the relationship between the main participants in the processes of (bio)degradation of SPs in various ecosystems (reservoirs with fresh and sea water, soils, etc.), namely the polymers themselves, the cells of microorganisms (MOs) participating in their degradation, and humic substances (HSs). HSs constitute a macrocomponent of natural non-living organic matter of aquatic and soil ecosystems, formed and transformed in the processes of mineralization of bio-organic substances in environmental conditions. Analysis of the main mechanisms of their influence on each other and the effects produced that accelerate or inhibit polymer degradation can create the basis for scientifically based approaches to the most effective solution to the problem of degradation of SPs, including in the form of microplastics. This review is aimed at comparing various aspects of interactions of SPs, MOs, and HSs in laboratory experiments (in vitro) and environmental investigations (in situ) aimed at the biodegradation of polymers, as well as pollutants (antibiotics and pesticides) that they absorb. Comparative calculations of the degradation velocity of different SPs in different environments are presented. A special place in the analysis is given to the elemental chemical composition of HSs, which are most successfully involved in the biodegradation of SPs. In addition, the role of photo-oxidation and photoaging of polymers under the influence of the ultraviolet spectrum of solar radiation under environmental conditions on the (bio)degradation of SPs in the presence of HSs is discussed.

Cross-Halbach magnetic levitation configuration for density-based measurement, separation and detection

Magnetic levitation (MagLev) is a well-documented and widely-applied technique in accurate, sensitive, and untethered testing of living and non-living materials in both macroscale and microscale. However, most magnetic levitation configurations face the dilemma between working range and sensitivity, since the distance between the two like-pole-facing magnets are in positive relationship with sensitivity, but negative with measuring range. And there exists a maximum distance for MagLev configurations where the misalignment happens when the distance is too large, which is a restriction on the working space and measurement range of the MagLev devices. In this paper, we propose a novel configuration based on the principle of Halbach array, namely the Cross-Halbach MagLev configuration. By doing parallel comparisons with the Standard MagLev consisting of magnets of the same size, we determined the superiority of the Cross-Halbach configuration in magnetic flux density (0.47 T) and B→∙∇B→z (6.25 T2/m), maximum distance (90 mm), sensitivity (525 mm/(g/cm3)) and wide linear zone on B→∙∇B→z (42 mm). To demonstrate and further explore the potential of the Cross-Halbach MagLev, we carried out a series of experiments, including density measurements of standard beads and different polymers, detection and separation of similar polymers with minute difference in density, and nondestructive detection of voids. The results indicate that the proposed magnetic levitation configuration is competent of density-based applications and can serve as a new solution to high-sensitivity measurement and detection.

Multi-laser nanoparticle tracking analysis (NTA): A unique method to visualize dynamic (shear) and dynamic (Brownian motion) light scattering and quantify nonliving natural organic matter (NNOM) in environmental water

Application of simultaneous multi-laser nanoparticle tracking analysis (NTA) to environmental water samples to investigate nonliving natural organic matter (NNOM) is introduced as an innovative method for observing particles directly in their native media. Multi-laser NTA results of particle visualization, particle number concentration, and particle size distribution elucidated particle dynamics in low and high total dissolved solids (TDS) aqueous environmental samples. A pond water sample and concentrate from a reverse osmosis (RO) treatment process (Stage 1) had 1.3 × 108 and 5.62 × 1019 particles/mL, respectively, (at time = 0) after filtration at 0.45 μm. Beyond the traditional applications for this instrument, this research presents novel evidence-based investigations that probe the existence of supramolecular structures in environmental waters during turbulence or quiescence. The pond water sample exhibited time-dependent aggregation as the volume distribution shifted to greater diameter during quiescence, compared to turbulence. Disaggregation (increased numbers of particles over time) was noted in the >250 nm to <600 nm region, and aggregation of >450 nm particles was also noted in the quiescent RO concentrate sample, indicative of depletion of small particles to form larger ones. Multi-laser NTA and dynamic light scattering (DLS) capabilities were compared and contrasted. DLS and NTA are different (complementary) particle sizing techniques. DLS yielded more information about the physical hydrogel in the NNOM hierarchy whereas multi-laser NTA better characterized meta-chemical and chemical hydrogel characteristics. Operationalization of innovation—moving from fundamental investigations to application—is supported by implementing novel analytical instrumentation as we address issues involving climate change, drought, and the scarcity of potable water. Multi-laser NTA can be used as a tool to study and optimize complex water and wastewater treatment processes. Questions about water treatment efficiencies, membrane fouling, assistance of pollutant transport, and carbon capture cycles affected by NNOM will benefit from insights from multi-laser NTA.

Various handcrafted artificial vessels: Evaluation of practicality and feasibility for supermicrosurgery training

BackgroundSupermicrosurgery demands more refined skills compared to traditional microsurgery, necessitating comprehensive training prior to clinical implementation. Despite the existence of various training models, they often fall short in terms of cost, ethical considerations, and infection risk. Our objective was to develop and evaluate novel training models for supermicrosurgery that are cost-effective, ethical, and risk-free. MethodsWe fabricated tubes using polyvinyl alcohol (PVA) liquid glue, polyvinyl acetate resin (PAR) wood glue, and hydrocolloid dressing (HCD), aiming to identify suitable, low-cost candidates for a supermicrosurgery training model. These tubes were anastomosed under a microscope using 10-0 or 11-0 nylon sutures. We assessed the time and cost involved in tube creation, their diameters, and the overall feasibility of the models. ResultsThe average time and cost to fabricate a 15-mm-long luminal tube were 33.5minutes and $0.02 USD for the PVA group, 23minutes and $0.02 USD for the PAR group, and 63seconds and $0.40 USD for the HCD group, respectively. The average diameter of the tubes was 0.49mm in the PVA group, 0.58mm in the PAR group, and 1.55mm in the HCD group. The PVA and PAR tubes, with their transparent and thin walls, facilitated easier evaluation of anastomosis patency compared to the HCD tubes. ConclusionWe have successfully developed new supermicrosurgery training models using non-living materials, characterized by their low cost, absence of ethical concerns, and elimination of infection risk. The PAR and PVA tubes, in particular, are suitable for residents' training in supermicrosurgery.

Protocell Effects on RNA Folding, Function, and Evolution.

ConspectusCreating a living system from nonliving matter is a great challenge in chemistry and biophysics. The early history of life can provide inspiration from the idea of the prebiotic "RNA World" established by ribozymes, in which all genetic and catalytic activities were executed by RNA. Such a system could be much simpler than the interdependent central dogma characterizing life today. At the same time, cooperative systems require a mechanism such as cellular compartmentalization in order to survive and evolve. Minimal cells might therefore consist of simple vesicles enclosing a prebiotic RNA metabolism.The internal volume of a vesicle is a distinctive environment due to its closed boundary, which alters diffusion and available volume for macromolecules and changes effective molecular concentrations, among other considerations. These physical effects are mechanistically distinct from chemical interactions, such as electrostatic repulsion, that might also occur between the membrane boundary and encapsulated contents. Both indirect and direct interactions between the membrane and RNA can give rise to nonintuitive, "emergent" behaviors in the model protocell system. We have been examining how encapsulation inside membrane vesicles would affect the folding and activity of entrapped RNA.Using biophysical techniques such as FRET, we characterized ribozyme folding and activity inside vesicles. Encapsulation inside model protocells generally promoted RNA folding, consistent with an excluded volume effect, independently of chemical interactions. This energetic stabilization translated into increased ribozyme activity in two different systems that were studied (hairpin ribozyme and self-aminoacylating RNAs). A particularly intriguing finding was that encapsulation could rescue the activity of mutant ribozymes, suggesting that encapsulation could affect not only folding and activity but also evolution. To study this further, we developed a high-throughput sequencing assay to measure the aminoacylation kinetics of many thousands of ribozyme variants in parallel. The results revealed an unexpected tendency for encapsulation to improve the better ribozyme variants more than worse variants. During evolution, this effect would create a tilted playing field, so to speak, that would give additional fitness gains to already-high-activity variants. According to Fisher's Fundamental Theorem of Natural Selection, the increased variance in fitness should manifest as faster evolutionary adaptation. This prediction was borne out experimentally during in vitro evolution, where we observed that the initially diverse ribozyme population converged more quickly to the most active sequences when they were encapsulated inside vesicles.The studies in this Account have expanded our understanding of emergent protocell behavior, by showing how simply entrapping an RNA inside a vesicle, which could occur spontaneously during vesicle formation, might profoundly affect the evolutionary landscape of the RNA. Because of the exponential dynamics of replication and selection, even small changes to activity and function could lead to major evolutionary consequences. By closely studying the details of minimal yet surprisingly complex protocells, we might one day trace a pathway from encapsulated RNA to a living system.

Integrated translation and metabolism in a partially self-synthesizing biochemical network.

One of the hallmarks of living organisms is their capacity for self-organization and regeneration, which requires a tight integration of metabolic and genetic networks. We sought to construct a linked metabolic and genetic network in vitro that shows such lifelike behavior outside of a cellular context and generates its own building blocks from nonliving matter. We integrated the metabolism of the crotonyl-CoA/ethyl-malonyl-CoA/hydroxybutyryl-CoA cycle with cell-free protein synthesis using recombinant elements. Our network produces the amino acid glycine from CO2 and incorporates it into target proteins following DNA-encoded instructions. By orchestrating ~50 enzymes we established a basic cell-free operating system in which genetically encoded inputs into a metabolic network are programmed to activate feedback loops allowing for self-integration and (partial) self-regeneration of the complete system.

Medicine, Life, and Transformations of Matter

This Ambix special issue explores premodern alchemical ideas and practices in their entanglements with medicine. It employs diverse methods, from traditional close reading to the new distant-reading framework of computational humanities, to investigate alchemical thought over a timespan of several centuries. In medieval times, everyday practices could offer heuristic models of material transformation – such as the fermentation of bread as a model for metallic transmutation (Schmechel). Paracelsus relied on “fire” to link his natural philosophy with his medical alchemy; new computational methods show how his ideas evolved over time (Hedesan). Early modern medical pluralism favoured the thriving of chemical medicine in Italy; diplomatic efforts introduced chemical remedies into acknowledged pharmacopoeias (Clericuzio). An English physician offers William Cavendish both practical distillation recipes and the hope of learning more about the principles of chemistry (Begley). In eighteenth-century France, Diderot draws on chemical ideas to blur the conceptual boundary between living and non-living matter (Wolfe). The papers largely adhere to integrated history and philosophy of science (iHPS) and to a pragmatist “operational ideal of knowledge” (Chang). They showcase the interdisciplinarity of premodern scientific thought and examine how medicine and alchemy, but also theory and (everyday) practice informed each other fruitfully across the ages.

Naturalizing relevance realization: why agency and cognition are fundamentally not computational.

The way organismic agents come to know the world, and the way algorithms solve problems, are fundamentally different. The most sensible course of action for an organism does not simply follow from logical rules of inference. Before it can even use such rules, the organism must tackle the problem of relevance. It must turn ill-defined problems into well-defined ones, turn semantics into syntax. This ability to realize relevance is present in all organisms, from bacteria to humans. It lies at the root of organismic agency, cognition, and consciousness, arising from the particular autopoietic, anticipatory, and adaptive organization of living beings. In this article, we show that the process of relevance realization is beyond formalization. It cannot be captured completely by algorithmic approaches. This implies that organismic agency (and hence cognition as well as consciousness) are at heart not computational in nature. Instead, we show how the process of relevance is realized by an adaptive and emergent triadic dialectic (a trialectic), which manifests as a metabolic and ecological-evolutionary co-constructive dynamic. This results in a meliorative process that enables an agent to continuously keep a grip on its arena, its reality. To be alive means to make sense of one's world. This kind of embodied ecological rationality is a fundamental aspect of life, and a key characteristic that sets it apart from non-living matter.

Theorising with the mycelium in the commingled world of young children’s musical play

ABSTRACT Inspired by Sheldrake’s study of fungi [Sheldrake, M. 2020. Entangled Life: How Fungi Make Our Worlds, Change Our Minds, and Shape Our Futures. London: Penguin Random House] and Barad’s idea of entanglement [Barad, K. 2007. Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning. Durham: Duke University Press], this paper explores music play with young children and artists, a practice that resists adult-centric approaches. As an embedded researcher within an early years arts organisation, I play with a diffractive methodology to read through ideas of Froebel with posthuman writings. Using slow-motion viewing of a video extract of musical play the vibrant agency of materials and sound emerges in micro-moments of playful music-making. Theorising with the mycelium produces ideas of extravagance, music and sound understood as lively intra-active and wild. It communicates through, and within, living and non-living matter. This view of music asks for artists to ‘do’ and say less, watch more and hold the space for the bursting forth of ripe and ready musical expressions. Through this pedagogical approach, children and adults can experience a sense of becoming with music, with the world.

The Study of Molecules and Processes in Solution: An Overview of Questions, Approaches and Applications

Many industrial processes, several natural processes involving non-living matter, and all the processes occurring within living organisms take place in solution. This means that the molecules playing active roles in the processes are present within another medium, called solvent. The solute molecules are surrounded by solvent molecules and interact with them. Understanding the nature and strength of these interactions, and the way in which they modify the properties of the solute molecules, is important for a better understanding of the chemical processes occurring in solution, including possible roles of the solvent in those processes. Computational studies can provide a wealth of information on solute–solvent interactions and their effects. Two major models have been developed to this purpose: a model viewing the solvent as a polarisable continuum surrounding the solute molecule, and a model considering a certain number of explicit solvent molecules around a solute molecule. Each of them has its advantages and challenges, and one selects the model that is more suitable for the type of information desired for the specific system under consideration. These studies are important in many areas of chemistry research, from the investigation of the processes occurring within a living organism to drug design and to the design of environmentally benign solvents meant to replace less benign ones in the chemical industry, as envisaged by the green chemistry principles. The paper presents a quick overview of the modelling approaches and an overview of concrete studies, with reference to selected crucial investigation themes.

Invasive species drive cross-ecosystem effects worldwide.

Invasive species are pervasive around the world and have profound impacts on the ecosystem they invade. Invasive species, however, can also have impacts beyond the ecosystem they invade by altering the flow of non-living materials (for example, nutrients or chemicals) or movement of organisms across the boundaries of the invaded ecosystem. Cross-ecosystem interactions via spatial flows are ubiquitous in nature, for example, connecting forests and lakes, grasslands and rivers, and coral reefs and the deep ocean. Yet, we have a limited understanding of the cross-ecosystem impacts invasive species have relative to their local effects. By synthesizing emerging evidence, here we demonstrate the cross-ecosystem impacts of invasive species as a ubiquitous phenomenon that influences biodiversity and ecosystem functioning around the world. We identify three primary ways by which invasive species have cross-ecosystem effects: first, by altering the magnitude of spatial flows across ecosystem boundaries; second, by altering the quality of spatial flows; and third, by introducing novel spatial flows. Ultimately, the strong impacts invasive species can drive across ecosystem boundaries suggests the need for a paradigm shift in how we study and manage invasive species around the world, expanding from a local to a cross-ecosystem perspective.

Assemblages as Ecologies

In this essay I draw on my art research and installation ‘Earthly Bodies, Subterranean Rhythms’ to posit assemblages as ecologies: platforms where specific agencies and interactions occur at different scales, including microscopic levels. Based on documentation images of my creative process, I delve into my experience exploring sculptural building and creative possibilities in more-than-human collaboration. This research involved observing subterranean bodies and temporalities, rhizomatic growth and mycorrhizal interactions as well as working in interspecies cooperation with oyster mushroom mycelium and wheatgrass roots. As spatial practices, architecture and sculpture have developed specific building methods. I expand on assemblage, the building method I worked with, seeking to articulate three lenses: sculptural, material and philosophical. Technically, an assemblage is a piece made by bringing together disparate elements. In this case it consisted mainly of ceramics, different earthly substrates, mycelium spawn, soil and seeds. Borrowing from Bennet’s ‘Vibrant Matter’ (2010) and Tsing’s ‘The Mushroom at the End of the World’ (2015) I reflect on living sculptures as interspecies assemblages: spaces of collaboration, cooperation and contamination between living and non-living bodies, matter and forces, human and more-than human agencies. From this perspective, assemblages are more than the sum of their parts as they have the capacity to re-make and transform us through encounters. A polyphony of worlding processes makes the collective architecture we live in: our shared world. Working in interspecies assemblages may enable more respectful and enjoyable ways of collective dwelling.

Morphological Entanglement in Living Systems.

Many organisms exhibit branching morphologies that twist around each other and become entangled. Entanglement occurs when different objects interlock with each other, creating complex and often irreversible configurations. This physical phenomenon is well studied in nonliving materials, such as granular matter, polymers, and wires, where it has been shown that entanglement is highly sensitive to the geometry of the component parts. However, entanglement is not yet well understood in living systems, despite its presence in many organisms. In fact, recent work has shown that entanglement can evolve rapidly and play a crucial role in the evolution of tough, macroscopic multicellular groups. Here, through a combination of experiments, simulations, and numerical analyses, we show that growth generically facilitates entanglement for a broad range of geometries. We find that experimentally grown entangled branches can be difficult or even impossible to disassemble through translation and rotation of rigid components, suggesting that there are many configurations of branches that growth can access that agitation cannot. We use simulations to show that branching trees readily grow into entangled configurations. In contrast to nongrowing entangled materials, these trees entangle for a broad range of branch geometries. We, thus, propose that entanglement via growth is largely insensitive to the geometry of branched trees but, instead, depends sensitively on timescales, ultimately achieving an entangled state once sufficient growth has occurred. We test this hypothesis in experiments with snowflake yeast, a model system of undifferentiated, branched multicellularity, showing that lengthening the time of growth leads to entanglement and that entanglement via growth can occur for a wide range of geometries. Taken together, our work demonstrates that entanglement is more readily achieved in living systems than in their nonliving counterparts, providing a widely accessible and powerful mechanism for the evolution of novel biological material properties.

Modeling grazer-mediated effects of demographic and material connectivity on giant kelp metapopulation dynamics

From dispersal-based metapopulations to meta-ecosystems that arise from flows of non-living materials, spatial connectivity is a major driver of population dynamics. One potentially important process is material transport between populations also linked by individual dispersal. Here, I explored material and demographic connectivity in metapopulations of giant kelp Macrocystis pyrifera, a foundation species that produces both detritus and reproductive spores. Kelp detritus (drift) subsidizes grazers, helping maintain the kelp forest ecosystem state. Drift could potentially be exchanged among kelp patches, but this is less studied than spore dispersal. Therefore, I built an ordinary differential equation (ODE) model to investigate conditions under which drift and/or spore connectivity promotes the kelp forest state. I fit statistical models (generalized linear mixed models, GLMMs) to observational data and used the GLMM’s predictions to validate the ODE model. My results suggest kelp patch dynamics are best explained by connectivity of both drift and spores, and that the impacts of these forms of connectivity depend on local grazer (urchin) abundance. Both models predicted greater kelp persistence in well-connected patches across a range of urchin densities. These effects were largely driven by drift, which reduced grazing in recipient patches and thereby enhanced spore recruitment. While testing these predictions will require greater empirical quantification of interpatch drift transport, my findings indicate drift connectivity may be an important spatial process in kelp forest systems. More broadly, this work highlights the role of meta-ecosystem dynamics within a single ecosystem type, reinforcing the need to expand traditional metapopulation perspectives to consider multiple forms of spatial connectivity.

Quantifying the Influence of X-Ray Irradiation on Cell-Size-Scale Viscoelasticity of Collagen Type 1.

X-rays are widely used in mammography and radiotherapy of breast cancer. The research has focused on the effects of X-rays on cells in breast tissues, instead of the tissues' nonliving material, extracellular matrix. It is unclear what the influence of X-ray irradiation is on the matrix's mechanical cues, known to regulate malignant cancer-cell behaviors. Here, we developed a technique based on magnetic microrheology that can quantify the influence of X-ray irradiation on matrix viscoelasticity--or (solid-like) elastic and (liquid-like) viscous characteristics--at cell-size scales. To model breast-tissue extracellular matrix, we used the primary component of the tissue matrix, collagen type 1, as it is for control, and as irradiated by X-rays (tube voltage 50 kV). We used a magnetic microrheometer to measure collagen matrices using 10-μm-diameter magnetic probes. In each matrix, the probes were nanomanipulated using controlled magnetic forces by the microrheometer while the probes' displacements were detected to measure the viscoelasticity. The collagen-matrix data involve with a typical spatial variation in viscoelasticity. We find that higher irradiation doses (320 Gy) locally reduce stiffness (soften) collagen matrices and increase their loss tangent, indicating an elevated liquid-like nature. For lower, clinically relevant irradiation doses (54 Gy), we find insignificant matrix-viscoelasticity changes. We provide this irradiation-related technique for detection, and modification, of matrix viscoelastic cues at cell-size scales. The technique enables enhanced characterization of irradiated tissue constituents in a variety of breast-cancer radiotherapy types.

A dynamic biointerface controls mussel adhesion.

The mussel-adherent secreta interface reveals how nonliving material can be compatible with tissue.

(Photoredox) Organocatalysis in the Emergence of Life: Discovery, Applications, and Molecular Evolution.

ConspectusLife as we know it is built on complex and perfectly interlocking processes that have evolved over millions of years through evolutionary optimization processes. The emergence of life from nonliving matter and the evolution of such highly efficient systems therefore constitute an enormous synthetic and systems chemistry challenge. Advances in supramolecular and systems chemistry are opening new perspectives that provide insights into living and self-sustaining reaction networks as precursors for life. However, the ab initio synthesis of such a system requires the possibility of autonomous optimization of catalytic properties and, consequently, of an evolutionary system at the molecular level. In this Account, we present our discovery of the formation of substituted imidazolidine-4-thiones (photoredox) organocatalysts from simple prebiotic building blocks such as aldehydes and ketones under Strecker reaction conditions with ammonia and cyanides in the presence of hydrogen sulfide. The necessary aldehydes are formed from CO2 and hydrogen under prebiotically plausible meteoritic or volcanic iron-particle catalysis in the atmosphere of the early Earth. Remarkably, the investigated imidazolidine-4-thiones undergo spontaneous resolution by conglomerate crystallization, opening a pathway for symmetry breaking, chiral amplification, and enantioselective organocatalysis. These imidazolidine-4-thiones enable α-alkylations of aldehydes and ketones by photoredox organocatalysis. Therefore, these photoredox organocatalysts are able to modify their aldehyde building blocks, which leads in an evolutionary process to mutated second-generation and third-generation catalysts. In our experimental studies, we found that this mutation can occur not only by new formation of the imidazolidine core structure of the catalyst from modified aldehyde building blocks or by continuous supply from a pool of available building blocks but also by a dynamic exchange of the carbonyl moiety in ring position 2 of the imidazolidine moiety. Remarkably, it can be shown that by incorporating aldehyde building blocks from their environment, the imidazolidine-4-thiones are able to change and adapt to altering environmental conditions without undergoing the entire formation process. The selection of the mutated catalysts is then based on the different catalytic activities in the modification of the aldehyde building blocks and on the catalysis of subsequent processes that can lead to the formation of molecular reaction networks as progenitors for cellular processes. We were able to show that these imidazolidine-4-thiones not only enable α-alkylations but also facilitate other important transformations, such as the selective phosphorylation of nucleosides to nucleotides as a key step leading to the oligomerization to RNA and DNA. It can therefore be expected that evolutionary processes have already taken place on a small molecular level and have thus developed chemical tools that change over time, representing a hidden layer on the path to enzymatically catalyzed biochemical processes.