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To test the hypothesis that an abiotic Earth and its inert atmosphere could form chemically reactive carbon-and nitrogen-containing compounds, we designed a plasma electrochemical setup to mimic lightning-induced electrochemistry under steady-state conditions of the early Earth. Air-gap electrochemical reactions at air-water-ground interfaces lead to remarkable yields, with up to 40 moles of carbon dioxide being reduced into carbon monoxide and formic acid, and 3 moles of gaseous nitrogen being fixed into nitrate, nitrite, and ammonium ions, per mole of transmitted electrons. Interfaces enable reactants (e.g., minerals) that may have been on land, in lakes, and in oceans to participate in radical and redox reactions, leading to higher yields compared to gas-phase-only reactions. Cloud-to-ground lightning strikes could have generated high concentrations of reactive molecules locally, establishing diverse feedstocks for early life to emerge and survive globally. [ABSTRACT FROM AUTHOR]

Phosphorylation reactions of glycerol were studied using different inorganic phosphates such as sodium phosphate, trimetaphosphate (a condensed phosphate), and struvite. The reactions were carried out in two non-aqueous solvents: formamide and a eutectic solvent consisting of choline-chloride and glycerol in a ratio of 1:2.5. The glycerol reacted in formamide and in the eutectic solvent with phosphate to yield its phosphorylated derivatives in the presence of silicates such as quartz sand and kaolinite clay. The reactions were carried out by heating glycerol with a phosphate source at 85 °C for one week and were analyzed by 31P-nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The yield of the phosphorylated glycerol was improved by the presence of silicates, and reached 90% in some experiments. Our findings further support the proposal that non-aqueous solvents are advantageous for the prebiotic synthesis of biomolecules, and suggest that silicates may have aided in the formation of organophosphates on the prebiotic earth. [ABSTRACT FROM AUTHOR]

The RNA World hypothesis is central to many current theories regarding the origin and early evolution of life. However, the formation of RNA by plausible prebiotic reactions remains problematic. Formidable challenges include glycosidic bond formation between ribose and the canonical nucleobases, as well as the inability of nucleosides to mutually select their pairing partners from a complex mixture of other molecules prior to polymerization. Here we report a one-pot model prebiotic reaction between a pyrimidine nucleobase (2,4,6-triaminopyrimidine, TAP) and ribose, which produces TAP-ribose conjugates in high yield (60-90%). When cyanuric acid (CA), a plausible ancestral nucleobase, is mixed with a crude TAP +ribose reaction mixture, micrometer-length supramolecular, noncovalent assemblies are formed. A major product of the TAP +ribose reaction is a β-ribofuranoside of TAP, which we term TARC. This nucleoside is also shown to efficiently form supramolecular assemblies in water by pairing and stacking with CA These results provide a proof-of-concept system demonstrating that several challenges associated with the prebiotic emergence of RNA, or pre-RNA polymers, may not be as problematic as widely believed. [ABSTRACT FROM AUTHOR]

This paper describes the fabrication of elastomeric three‐dimensional (3D) structures starting from two‐dimensional (2D) sheets using a combination of direct‐ink printing and relaxation of strain. These structures are fabricated in a two‐step process: first, elastomeric inks are deposited as 2D structures on a stretched elastomeric sheet, and second, after curing of the elastomeric inks, relaxation of strain in the 2D sheet causes it to deform into a 3D shape. To predict bending of elastomeric objects fabricated with this technique, a simple mechanical model is developed. The strategy of using initially 2D materials to fabricate 3D structures offers four new features that complement digital fabrication techniques. (i) It provides a simple route to create shapes with complex curves, suspended features, and internal cavities. (ii) It is a faster method of fabricating some types of shapes than "conventional" 3D printing, because the features are printed in 2D. (iii) It forms surfaces that can be both smoother, and structured in a way that is not compatible with layer‐by‐layer processing. (iv) It forms structures that can be deformed reversibly after fabrication by reapplying strain. This paper demonstrates these features by fabrication of helices, structures inspired by cubes and tables, "pop‐up" structures, and soft grippers. Printing two‐dimensional (2D) structures on stretched, elastomeric substrates forms three‐dimensional (3D) structures upon relaxation. This technique allows for precise control over the curvature of 3D structures by exact ink patterning, provides a number of advantages over commonly used technologies for 3D printing, and is attractive for rapid prototyping and fabrication of structures that are deformable and/or contain hollow components. [ABSTRACT FROM AUTHOR]

To test the hypothesis that an abiotic Earth and its inert atmosphere could form chemically reactive carbon- and nitrogen-containing compounds, we designed a plasma electrochemical setup to mimic lightning-induced electrochemistry under steady-state conditions of the early Earth. Air-gap electrochemical reactions at air-water-ground interfaces lead to remarkable yields, with up to 40 moles of carbon dioxide being reduced into carbon monoxide and formic acid, and 3 moles of gaseous nitrogen being fixed into nitrate, nitrite, and ammonium ions, per mole of transmitted electrons. Interfaces enable reactants (e.g., minerals) that may have been on land, in lakes, and in oceans to participate in radical and redox reactions, leading to higher yields compared to gas-phase-only reactions. Cloud-to-ground lightning strikes could have generated high concentrations of reactive molecules locally, establishing diverse feedstocks for early life to emerge and survive globally., Competing Interests: Competing interests statement:Harvard University has filed patent applications PCT/US2023/077332 and PCT/US2024/017763.

The nature of the processes at the origin of life that selected specific classes of molecules for broad incorporation into cells is controversial. Among those classes selected were polyisoprenoids and their derivatives. This paper tests the hypothesis that polyisoprenoids were early contributors to membranes in part because they (or their derivatives) could facilitate charge transport by quantum tunneling. It measures charge transport across self-assembled monolayers (SAMs) of carboxyl-terminated monoterpenoids (O 2 C(C 9 HX)) and alkanoates (O 2 C(C 7 HX)) with different degrees of unsaturation, supported on silver (Ag TS ) bottom electrodes, with Ga 2 O 3 /EGaIn top electrodes. Measurements of current density of SAMs of linear length-matched hydrocarbons-both saturated and unsaturated-show that completely unsaturated molecules transport charge faster than those that are completely saturated by approximately a factor of ten. This increase in relative rates of charge transport correlates with the number of carbon-carbon double bonds, but not with the extent of conjugation. These results suggest that polyisoprenoids-even fully unsaturated-are not sufficiently good tunneling conductors for their conductivity to have favored them as building blocks in the prebiotic world., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Aqueous solutions of the achiral, monomeric, nucleobase mimics (2,4,6-triaminopyrimidine, TAP, and a cyanuric acid derivative, CyCo6) spontaneously assemble into macroscopic homochiral domains of supramolecular polymers. These assemblies exhibit a high degree of chiral amplification. Addition of a small quantity of one handedness of a chiral derivative of CyCo6 generates exclusively homochiral structures. This system exhibits the highest reported degree of chiral amplification for dynamic helical polymers or supramolecular helices. Significantly, homochiral polymers comprised of hexameric rosettes with structural features that resemble nucleic acids are formed from mixtures of cyanuric acid (Cy) and ribonucleotides (l-, d-pTARC) that arise spontaneously from the reaction of TAP with the sugars. These findings support the hypothesis that nucleic acid homochirality was a result of symmetry breaking at the supramolecular polymer level., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The poor reactivity of insoluble phosphates, such as apatite-group minerals, has been a long-appreciated obstacle for proposed models of prebiotic organophosphate formation. This obstacle presents a significant challenge to the nascent development of an RNA world and other models for the origins of life on Earth. Herein, we demonstrate that a scenario based on the formation of a urea/ammonium formate/water (UAFW) eutectic solution leads to an increase in phosphorylation when compared to urea alone for phosphate sources of varying solubility. In addition, under evaporative conditions and in the presence of MgSO 4 , the UAFW eutectic mobilizes the phosphate sequestered in water-insoluble hydroxyapatite, giving rise to a marked increase in phosphorylation. These results suggest that the prebiotic concentrations of urea in a geologically plausible evaporitic environment could solve the problem of organic phosphorylation on a prebiotic Earth., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)