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The self-assembly of peptides and proteins frequently shows structural plasticity depending on subtle alterations. The acquisition of structural data of these peptide assemblies with atomic level precision will be crucial to understand and predict assembled morphologies.

The two-dimensional (2D) homogeneous assembly of nanoparticle monolayer arrays onto a broad range of substrates constitutes an important challenge for chemistry, nanotechnology, and material science. α-Synuclein (αS) is an intrinsically disordered protein associated with neuronal protein complexes and has a high degree of structural plasticity and chaperone activity. The C-terminal domain of αS has been linked to the noncovalent interactions of this protein with biological targets and the activity of αS in presynaptic connections. Herein, we have systematically studied peptide fragments of the chaperone-active C-terminal sequence of αS and identified a 17-residue peptide that preserves the versatile binding nature of αS. Attachment of this short peptide to gold nanoparticles afforded colloidally stable nanoparticle suspensions that allowed the homogeneous 2D adhesion of the conjugates onto a wide variety of surfaces, including the formation of crystalline nanoparticle superlattices. The peptide sequence and the strategy reported here describe a new adhesive molecule for the controlled monolayer adhesion of metal nanoparticles and sets a stepping-stone toward the potential application of the adhesive properties of αS This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [BIO2015-70092-R, SAF2017-89890-R], the Xunta de Galicia (ED431C 2017/25, 2016-AD031, AGAUR (2017 SGR 324), and Centro Singular de Investigación de Galicia accreditation 2016–2019, ED431G/09), the ISCIII (COV20/00297), and the European Union (European Regional Development Fund – ERDF). X.S. acknowledges funding from the ERC (CONCERT-648201). IRB Barcelona is the recipient of a Severo Ochoa Award (Government of Spain). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Grant (DYNAP-677786), and a Young Investigator Grant from the HFSP (RGY0066/2017) SI

One-dimensional (1D) supramolecular polymers are commonly found in natural and synthetic systems to prompt functional responses that capitalise on hierarchical molecular ordering. Despite amphiphilic self-assembly being significantly studied in the context of aqueous encapsulation and autopoiesis, very little is currently known about the physico-chemical consequences and functional role of 1D supramolecular polymerisation confined in aqueous compartments. Here, we describe the different phenomena that resulted from the chemically triggered supramolecular fibrillation of synthetic peptide amphiphiles inside water microdroplets. The confined connection of suitable dormant precursors triggered a physically autocatalysed chemical reaction that resulted in functional environmental responses such as molecular uptake, fusion and chemical exchange. These results demonstrate the potential of minimalistic 1D supramolecular polymerisation to modulate the behaviour of individual aqueous entities with their environment and within communities., One-dimensional (1D) supramolecular polymers are commonly found in natural and synthetic systems but very little is currently known about the physico-chemical consequences and functional role of 1D supramolecular polymerisation confined in aqueous compartments. Here, the authors describe the different phenomena that resulted from the chemically triggered supramolecular fibrillation of synthetic peptide amphiphiles inside water microdroplets.

Antivirals are now more important than ever. To efficiently inhibit virus replication, antiviral multivalent strategies need sufficient affinity to overcome the excellent matching between the virus and its receptor. This report highlights a phage capsid scaffold strategy that can be used to precisely position sialic acid moieties to inhibit influenza A virus replication.

In this work we report a rational design strategy for the identification of new peptide prototypes for the non-disruptive supramolecular permeation of membranes and the transport of different macromolecular giant cargos. The approach targets a maximal enhancement of helicity in the presence of membranes with sequences bearing the minimal number of cationic and hydrophobic moieties. The here reported folding enhancement in membranes allowed the selective non-lytic translocation of different macromolecular cargos including giant proteins. The transport of different high molecular weight polymers and functional proteins was demonstrated in vesicles and in cells with excellent efficiency and optimal viability. As a proof of concept, functional monoclonal antibodies were transported for the first time into different cell lines and cornea tissues by exploiting the helical control of a short peptide sequence. This work introduces a rational design strategy that can be employed to minimize the number of charges and hydrophobic residues of short peptide carriers to achieve non-destructive transient membrane permeation and transport of different macromolecules., The helical enhancement of a short oligoalanine peptide scaffold in anionic membranes triggered the supramolecular assembly of a nanopore, which allowed the transport and release of proteins in the cytosol of cells and tissues.

This is the peer reviewed version of the following article: S. Díaz, I. Insua, G. Bhak, J. Montenegro, Chem. Eur. J. 2020, 26, 14765, which has been published in final form at https://doi.org/10.1002/chem.202003265. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. The inherent ability of peptides to self-assemble with directional and rationally predictable interactions has fostered a plethora of synthetic two-dimensional (2D) supramolecular biomaterials. However, the design of peptides with hierarchical assembly in different dimensions across mesoscopic lengths remains a challenging task. We here describe the structural exploration of a d/l-alternating cyclic octapeptide capable of assembling one-dimensional (1D) nanotubes in water, which subsequently pack laterally to form giant 2D nanosheets up to 500 μm long with a constant 3.2 nm thickness. Specific amino acid mutations allowed the mapping of structure–assembly relationships that determine 2D self-assembly. Nine peptide modifications were studied, revealing key features in the peptide sequence that nanosheets tolerated, while a total of three peptide variants included modifications that compromised their 2D arrangement. These lessons will serve as guide and inspiration for new 2D supramolecular peptide designs This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [SAF2017-89890-R], Xunta de Galicia (AD031 2016, ED431C 2017/25 and ED431G2019/03) and the European Commission (EC) (European Regional Development Fund-ERDF) Instituto de Salud Carlos III (COV20/00297). I.I. thanks the European Commission (EC) and AEI for MSCA-IF (2018-843332) and Juan de la Cierva (FJCI-2017-31795) fellowships, respectively. J.M. thanks the Ramón y Cajal (RYC-2013-13784), ERC- STG (DYNAP, 2016-677786), ERC-POC (TraffikGene, 2019-838002) and Human Frontier Science Programme Young Investigator Grant (RGY0066/2017) for funding SI

This is the Accepted Manuscript of the following article: Méndez-Ardoy, A., Granja, J., & Montenegro, J. (2018). pH-Triggered self-assembly and hydrogelation of cyclic peptide nanotubes confined in water micro-droplets. Nanoscale Horizons. http://dx.doi.org/10.1039/c8nh00009c The controlled one-dimensional supramolecular polymerization of synthetic building blocks in confined spaces constitutes a key challenge to simplify the understanding of the fundamental physical principles behind the behavior of more complex encapsulated polymer networks. Cyclic peptide nanotubes constitute an optimal scaffold for the fabrication of hierarchical one-dimensional self-assembled architectures. Herein we report the pH-controlled nanotube formation and fibrillation of supramolecular cyclic peptides in confined aqueous droplets. The externally triggered self-assembly of these peptides gave rise to viscoelastic hydrogels in which the one-dimensional molecular arrangement was perfectly preserved from the nano- to the micro-scale. The cyclic peptide building blocks were confined inside water microdroplets and the base-triggered supramolecular polymerization was externally triggered and followed by confocal microscopy showing that the confined fibrillation spanned and affected the shape of the droplet micro container This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [SAF2017-89890-R, CTQ2014-59646-R and CTQ2016-78423-R], the Xunta de Galicia (ED431G/09, ED431C 2017/25 and 2016-AD031) and the ERDF. A. M.-A. received a MCIF from the EC (GLYCONANOPEP-750248). J. M. holds a Ramón y Cajal (RYC-2013-13784), an ERC-Stg (DYNAP-677786) and a Young Investigator Grant from the HFSP (RGY0066/2017) SI

The recent advances in the supramolecular polymerization of synthetic building blocks in aqueous conditions has given rise to new artificial and biocompatible functional materials. However, despite the importance of spatially resolved self‐assembly for natural and artificial molecular machines, the spatial control of supramolecular polymerization with synthetic monomers has not been experimentally established yet. Here we describe a microfluidic‐regulated tandem process of supramolecular polymerization and droplet encapsulation to control the position of self‐assembled microfibrillar bundles of cyclic peptide nanotubes in water droplets. This method allowed the precise preferential localization of the fibres either at the interface or into the core of the droplets. UV absorbance, circular dichroism and fluorescence microscopy indicated that the microfluidic control of the stimuli (changes in pH or ionic strength) can be employed to adjust the packing degree and the spatial position of microfibrillar bundles of cyclic peptide nanotubes. Additionally, this spatially organized supramolecular polymerization of peptide nanotubes was applied in the assembly of highly ordered two‐dimensional droplet networks This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [SAF2017-89890-R, CTQ2016-78423-R], the Xunta de Galicia (ED431G/09, ED431C 2017/25 and 2016-AD031) and the ERDF. A. M.-A. received a MCIF from the EC (GLYCONANOPEP-750248). J. M. holds a Ramón y Cajal (RYC-2013-13784), an ERC-Stg (DYNAP-677786) and a Young Investigator Grant from the HFSP (RGY0066/2017). J. R. G. thanks to the mobility program (PRX17/00147) SI

Despite recent developments in two-dimensional self-assembly, most supramolecular 2D materials are assembled by tedious methodologies, with complex surface chemistry and small sizes. We here report d/l-alternating cyclic peptides that undergo one-dimensional self-assembly into amphiphilic nanotubes, which subsequently arrange as tubular bilayers to form giant nanosheets in the mesoscale. Reversible transitions between the assembled, dispersed, and aggregated states of these nanosheets can be triggered by external stimuli. The characteristic flexibility, defined chemical topology, and length scale of these nanosheets set a clear distinction between this new supramolecular architecture and previously reported 2D nanostructures. The sequential 1D-to-2D self-assembly of peptides described here provides a conceptually new approach to achieve two-dimensional materials with hierarchical organization. These giant nanosheets represent one of the largest 2D supramolecular materials ever made, with potential application as long-range molecular transporters, responsive surfaces, and (bio)sensors This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [SAF2017-89890-R], the Xunta de Galicia (ED431C 2017/25, 2016-AD031 and Centro Singular de Investigación de Galicia accreditation 2016-2019, ED431G/09), the ISCIII (RD16/0008/003), and the European Union (European Regional Development Fund, ERDF). I.I. thanks the European Commission for a Marie Curie fellowship (MSCA-IF-2018-843332) and the Spanish AEI for a Juan de la Cierva—Formación Fellowship (FJCI-2017-31795). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP-677786), and a Young Investigator Grant from the HFSP (RGY0066/2017). We thank Dr. Eugenio Solla, Prof. Juan Granja, Dr. Julian Bergueiro, Dr. Andreas Vargas Jentzsch, and Dr. Mark J. van Raaij for helpful discussions. We also thank Dr. Bergueiro for Figure 1 and Dr. Vargas Jentzsch for assistance with DFT calculations SI

Tracking the pH with spatiotemporal resolution is a critical challenge for synthetic chemistry, chemical biology and beyond. Over the last decade different small probes and supramolecular systems have emerged for in celluloor in vivo pH tracking. However, pH reporting still presents critical limitations such as background reduction, sensor improved stability, cell targeting, endosomal escape, near and far infrared ratiometric pH tracking, adaptation to the new imaging techniques (i.e. super‐resolution), etc. These challenges will demand the combined efforts of synthetic and supramolecular chemistry working together to develop a next generation of smart materials that will resolve the current limitations. In this review we describe the recent advances in the synthesis of small fluorescent probes together with new supramolecular functional systems employed for pH tracking with emphasis in ratiometric probes. The combination of organic synthesis and stimuli‐responsive supramolecular functional materials will be essential to solve future challenges of pH tracking such as the improved signal to noise ratio, on target activation and microenvironment reporting This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [SAF2017-89890-R], the Xunta de Galicia (ED431C 2017/25, 2016-AD031 and Centro Singular de Investigación de Galicia accreditation 2016–2019, ED431G/09), the ISCIII (RD16/0008/003), and the European Union (European Regional Development Fund –ERDF). A.M. received a Marie Curie fellowship (GLYCONANOPEP-750248). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP-677786) and a Young Investigator Grant from the Human Frontier Science Research Program (RGY0066/2017) SI

Here we present the synthesis and post-polymerisation modification of poly(acryloyl hydrazide), a versatile scaffold for the preparation of functional polymers: poly(acryloyl hydrazide) was prepared from commercially available starting materials in a three step synthesis on a large scale, in good yields and high purity. Our synthetic approach included the synthesis of a Boc-protected acryloyl hydrazide, the preparation of polymers via RAFT polymerisation and the deprotection of the corresponding Boc-protected poly(acryloyl hydrazide). Post-polymerisation modification of poly(acryloyl hydrazide) was then demonstrated using a range of conditions for both hydrophilic and hydrophobic aldehydes. These experiments demonstrate the potential of poly(acryloyl hydrazide) as a scaffold in the synthesis of functional polymers, in particular those applications where in situ screening of the activity of the functionalised polymers may be required (e.g. biological applications) This work was supported by the Royal Society, U.K (IE130688) and the Wellcome Trust (177ISSFPP). F. F.-T. thanks the Birmingham Science City and the European Regional Development Fund, the Royal Society (RG140273), and the University of Birmingham (John Evans Fellowship). J. M. thanks funding from MINECO (CTQ2014-59646-R, RYC-2013-1378) the Xunta de Galicia (ED431G/09 and 2016-AD031) and the ERC (Stg-DYNAP-677786) SI

31 p.-6 fig.-14 fig. supl., The cell membrane regulates the exchange of molecules and information with the external environment. However, this control barrier hinders the delivery of exogenous bioactive molecules that can be applied to correct cellular malfunctions. Therefore, the traffic of macromolecules across the cell membrane represents a great challenge for the development of the next generation of therapies and diagnostic methods. Cell‐penetrating peptides are short peptide sequences capable of delivering a broad range of biomacromolecules across the cellular membrane. However, penetrating peptides still suffer from limitations, mainly related to their lack of specificity and potential toxicity. Glycosylation has emerged as a potential promising strategy for the biological improvement of synthetic materials. In this work we have developed a new convergent strategy for the synthesis of penetrating peptides functionalized with glycan residues by an oxime bond connection. The uptake efficiency and intracellular distribution of these glycopeptides have been systematically characterized by means of flow cytometry and confocal microscopy and in zebrafish animal models. The incorporation of these glycan residues into the peptide structure influenced the internalization efficiency and cellular toxicity of the resulting glycopeptide hybrids in the different cell lines tested. The results reported herein highlight the potential of the glycosylation of penetrating peptides to modulate their activity., We acknowledge funding from the Spanish Agencia Estatal de Investigación (AEI; CTQ2014‐59646‐R, SAF2017‐89890‐R, CTQ2016‐76263‐P, CTQ2015‐64597‐C2‐2P), the Xunta de Galicia (ED431G/09, ED431C 2017/25, and 2016‐AD031), and the ERDF. I.G. received a predoctoral fellowship from the Xunta de Galicia (ED481A‐2018/116). A.R. received a predoctoral fellowship from the Fundación Segundo Gil Dávila. J.G.‐V. and L.S. acknowledge financial support received from the Xunta de Galicia (Galicia, Spain) under the Grupos de Referencia Competitiva Programme: Project GRC2014/010. J.M. received a Ramón y Cajal (RYC‐2013‐13784), an ERC Starting Investigator Grant (DYNAP‐677786) and a Young Investigator Grant from the HFSP (RGY0066/2017).

This is the Accepted Manuscript of the following article: Juanes, M., Creese, O., Fernández-Trillo, P., & Montenegro, J. (2019). Messenger RNA delivery by hydrazone-activated polymers. Medchemcomm, 10(7), 1138-1144. doi: 10.1039/c9md00231f The intracellular delivery of DNA and RNA therapeutics requires the assistance of vectors and/or nucleotide modifications to protect the nucleic acids against host nucleases and promote cellular internalization and release. Recently, messenger RNA (mRNA) has attracted much attention due to its transient activity and lack of genome permanent recombination and persistent expression. Therefore, there is a strong interest in the development of conceptually new non-viral vectors with low toxicity that could improve mRNA transfection efficiency. We have recently introduced the potential of polyhydrazones and the importance of the degree of polymerization for the delivery of siRNA and plasmid DNA. Here, we demonstrate that this technology can be easily adapted to the more interesting complexation and delivery inside living cells of mRNA. The polyplexes resulting from the combination of the amphiphilic polyhydrazone were characterized and the transfection efficiency and cell viability were studied for a discrete collection of functionalized polyhydrazones. The results obtained demonstrated the versatility of these polymeric vectors as excellent candidates for the delivery of mRNA and validate the easy adaptability of the technology to more sensitive and therapeutically relevant nucleic acids This work has received financial support from Spanish Agencia Estatal de Investigación (AEI) [CTQ2014-59646-R, SAF2017-89890-R], the Xunta de Galicia (ED431C 2017/25, 2016-AD031 and Centro singular de investigación de Galicia accreditation 2016–2019, ED431G/09) and the European Union (European Regional Development Fund - ERDF). M.J. received a F.P.I. fellowship from MINECO (CTQ2014-59646- R). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP- 677786) and a Young Investigator Grant from the Human Frontier Science Research Program (RGY0066/2017). F.F.T. thanks the Birmingham Science City and the European Regional Development Fund, and the University of Birmingham (John Evans Fellowship). O.C. thanks the Midlands Integrative Biosciences Training Partnership (MIBTP) for the PhD scholarship SI

The formation of oligomeric soluble aggregates is related to the toxicity of amyloid peptides and proteins. In this manuscript, we report the use of a ruthenium polypyridyl complex ([Ru(bpy)2(dpqp)]2+) to track the formation of amyloid oligomers at different times using photoluminescence anisotropy. This technique is sensitive to the rotational correlation time of the molecule under study, which is consequently related to the size of the molecule. [Ru(bpy)2(dpqp)]2+ presents anisotropy values of zero when free in solution (due to its rapid rotation and long lifetime) but larger values as the size and concentration of amyloid-β (Aβ) oligomers increase. Our assays show that Aβ forms oligomers immediately after the assay is started, reaching a steady state at ∼48 h. SDS–PAGE, DLS, and TEM were used to confirm and characterize the formation of oligomers. Our experiments show that the rate of formation for Aβ oligomers is temperature dependent, with faster rates as the temperature of the assay is increased. The probe was also effective in monitoring the formation of α-synuclein oligomers at different times AAM thanks the Welch Foundation (Grant C-1743) and JM thanks AEI (SAF2017-89890-R), ERC (DYNAP-677786) and HFSP (RGY0066/2017) for financial support SI

Linear peptide amphiphiles are excellent biocompatible scaffolds for the hierarchical self-assembly of one dimensional nanostructures in aqueous media. However, their structural exploration and screening of self-assembling properties is often limited by time-consuming synthesis and purification steps. We here describe the application of the oxime bond as a powerful synthetic tool towards the conjugation of peptide heads bearing a hydroxylamine group with hydrophobic aldehyde tails. This methodology allowed the quick prepraration of a small library of oxime-connected peptide amphiphiles, whose supramolecular screening revealed nano-to-micro fibrillation with dependency on their chemical structure. These results demonstrate the simplicity and the synthetic potential of the oxime conjugation for the preparation of peptide amphiphiles with improved self-assembling capabilities This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [CTQ2014-59646-R, SAF2017-89890-R], the Xunta de Galicia (ED431G/09, ED431C 2017/25 and 2016-AD031) and the ERDF. I.I. thanks the Spanish AEI for a Juan de la Cierva -Formación fellowship (FJCI-2017-31795). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP-677786) and a Young Investigator Grant from the Human Frontier Science Research Program (RGY0066/2017) SI

The internalisation and delivery of active substances into cells is a field of growing interest for chemical biology and therapeutics. As we move from small-molecule-based drugs towards bigger cargos, such as antibodies, enzymes, nucleases or nucleic acids, the development of efficient delivery systems becomes critical for their practical application. Different strategies and synthetic carriers have been developed; these include cationic lipids, gold nanoparticles, polymers, cell-penetrating peptides (CPPs), protein surface modification etc. However, all of these methodologies still present limitations relating to the precise targeting of the different intracellular compartments and, in particular, difficulties in access to the cellular cytosol. Additionally, the precise quantification of the cellular uptake of a compound is not enough to demonstrate delivery and/or functional activity. Therefore, methods to determine cellular distributions of cargos and carriers are of critical importance for identifying the barriers that are blocking the activity. Herein we survey the different techniques that can currently be used to track and to monitor the subcellular localisation of the synthetic compounds that we deliver inside cells.

Subnanometric noble metal clusters, composed by only a few atoms, behave like molecular entities and display magnetic, luminescent and catalytic activities. However, non-covalent interactions of molecular metal clusters, lacking of any ligand or surfactant, have not been seen at work. Theoretically attractive and experimentally discernable, van der Waals forces and non-covalent interactions at the metal/organic interfaces will be crucial to understand and develop the next generation of hybrid nanomaterials. Here, we present experimental and theoretical evidence of non-covalent interactions between subnanometric metal (0) silver clusters and aromatic rings and their application in the preparation of 1D self-assembled hybrid architectures with ditopic peptide nanotubes. Atomic force microscopy, fluorescence experiments, circular dichroism and computational simulations verified the occurrence of these interactions in the clean and mild formation of a novel peptide nanotube and metal cluster hybrid materials. The findings reported here confirmed the sensitivity of silver metal clusters of small atomicity towards non-covalent interactions, a concept that could find multiple applications in nanotechnology. We conclude that induced supramolecular forces are optimal candidates for the precise spatial positioning and properties modulation of molecular metal clusters. The reported results herein outline and generalize the possibilities that non-covalent interactions will have in this emerging field This work was supported by the Spanish Ministry of Economy and Competitivity (Mineco) and the ERDF [CTQ2010-15725, CTQ2013-43264-R, MAT2011-28673-C02-01, MAT2012-36754-C02-01], by the Xunta de Galicia (GRC2006/132, GRC2013/044, EM 2012/117). J.M. received a Ramón y Cajal contract from the Mineco. We also thank the ORFEO-CINCA network and Mineco through CTQ2014-51912-REDC SI

The straightforward preparation of glycosyl neoconjugates by oxime (or hydrazone) bond formation represents a key bioorthogonal tool in chemical biology. However, when this strategy is employed by reacting the reducing end of the glycan moiety, the configuration and the stereochemical information is lost due to partial (or complete) opening of the glycan cyclic hemiacetal and the formation of the corresponding opened tautomers. We have completed the synthesis of a library of glycosyl aldehydes to be used as scaffold for the synthesis of neoglycoconjugates via oxime bond formation. These glycosyl aldehydes constitute a simple and accessible alternative to avoid loss of chiral information when conjugating, by oxime (or hydrazone) bonds, the aldehyde functionality present at the reducing end of natural carbohydrates This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [CTQ2014–59646-R], the Xunta de Galicia (ED431G/09, ED431C 2017/25 and 2016-AD031) and the ERDF. J.M. received a Ramón y Cajal (RYC-2013–13784), an ERC-Stg (DYNAP- 677786) and a Young Investigator Grant from the Human Frontier Science Research Program (RGY0066/2017) SI

This manuscript has been accepted after peer review and appears as anAccepted Article online prior to editing, proofing, and formal publicationof the final Version of Record (VoR). This work is currently citable byusing the Digital Object Identifier (DOI) given below. The VoR will bepublished online in Early View as soon as possible and may be differentto this Accepted Article as a result of editing. Readers should obtainthe VoR from the journal website shown below when it is publishedto ensure accuracy of information. The authors are responsible for thecontent of this Accepted Article The intracellular transport of exogenous proteins has emerged as one of the most promising methodologies for biotechnology and chemical biology. Current protein delivery is mainly approached by liposome encapsulation, translational fusion and ionic/hydrophobic non‐covalent aggregation with transporting molecular vehicles. We here introduce the concept of supramolecular recognition and selective transport of proteins by peptide hybrid materials. We have designed a helical amphiphilic cationic peptide that bears two orthogonal alkoxyamines for the precise anchoring of protein ligands. After the attachment of these protein ligands, the peptide showed a high binding affinity for its protein target (i.e. mannose/Concanavalin A, Biotin/Streptavidin). The resulting peptide/protein hybrids were taken up by human cells such as HeLa and HepG2. The concept described in this manuscript could potentially be adapted, through the appropriate choice of ligands, to the transport of other proteins with suitable supramolecular binding motifs This work was partially supported by the Spanish Agencia Estatal de Investigación (AEI) [CTQ2014-59646-R, CTQ2013-43264-R, SAF2017-89890-R], the Xunta de Galicia (ED431G/09, ED431C 2017/25 and 2016-AD031) and the ERDF. We thank Pili Canoa (CACTI, UVIGO) for assistance with the SPR measurements. M.J. received a F.P.I. fellowship from MINECO (CTQ2014-59646-R). J.M. received a Ramón y Cajal (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP- 677786) and a Young Investigator Grant from the Human Frontier Science Research Program (RGY0066/2017) SI

Binding constants, Log K ≈ 6.6 M-1, and NMR characterization of the complexes formed by sulfobetaines and cucurbit[7]uril (CB7) support the electrostatic interaction as major driving force. This very strong binding motif is cross-linked by additional CB7 molecules resulting in the formation of supramolecular nanoparticles (SNPs) with an average diameter of 172 nm and negative surface potential. The time course evolution of the particle size and the surface potential suggests the very fast formation of an amorphous aggregate that absorbs additional amount of sulfobetaine. These aggregates afford very stable (more than two weeks) nanoparticles in aqueous dispersion. The reversibility of the sulfobetaine/CB7 host:guest complexes allows SNPs disaggregation by adding a competitive guest as shown by treatment with tetraethylammonium chloride. The addition of this competitive cation triggers a SNPs to micelle transition. The potential application of these nanoparticles as drug delivery vehicles was investigated by using carboxyfluorescein. These experiments revealed that upon externally induced disruption of the SNPs (by tetraethylammonium chloride) the fluorescent dye was trapped into micellar aggregates that can be further disrupted by cyclodextrin additionhttp://www.usc.es/ Financial support from Ministerio de Economia y Competitividad of Spain (projects CTQ2014-55208-P, CTQ2017-84354-P, CTQ2014-59646-R and MAT2015-67458-P), Xunta de Galicia (GR 2007/085; IN607C 2016/03 and Centro singular de investigación de Galicia accreditation 2016-2019, ED431G/09) and the European Union (European Regional Development Fund – ERDF), is gratefully acknowledged. J.M. received a Ramón y Cajal (RYC-2013- 13784) and a starting grant from the ERC (DYNAP677786) SI

The objective of this Feature Article is to reflect on the importance of established and emerging principles of supramolecular organic chemistry to address one of the most persistent problems in life sciences. The main topic is dynamic covalent chemistry on cell surfaces, particularly disulfide exchange for thiol-mediated uptake. Examples of boronate and hydrazone exchange are added for contrast, comparison and completion. Of equal importance are the discussions of proximity effects in polyions and counterion hopping, and more recent highlights on ring tension and ion pair-π interactions. These lessons from supramolecular organic chemistry apply to cell-penetrating peptides, particularly the origin of "arginine magic" and the "pyrenebutyrate trick," and the currently emerging complementary "disulfide magic" with cell-penetrating poly(disulfide)s. They further extend to the voltage gating of neuronal potassium channels, gene transfection, and the delivery of siRNA. The collected examples illustrate that the input from conceptually innovative chemistry is essential to address the true challenges in biology beyond incremental progress and random screening.

The hydrazone modulation of a penetrating peptide carrier is reported as a suitable and straightforward strategy for the delivery of Cas9 inside living cells., The discovery of RNA guided endonucleases has emerged as one of the most important tools for gene edition and biotechnology. The selectivity and simplicity of the CRISPR/Cas9 strategy allows the straightforward targeting and editing of particular loci in the cell genome without the requirement of protein engineering. However, the transfection of plasmids encoding the Cas9 and the guide RNA could lead to undesired permanent recombination and immunogenic responses. Therefore, the direct delivery of transient Cas9 ribonucleoprotein constitutes an advantageous strategy for gene edition and other potential therapeutic applications of the CRISPR/Cas9 system. The covalent fusion of Cas9 with penetrating peptides requires multiple incubation steps with the target cells to achieve efficient levels of gene edition. These and other recent reports suggested that covalent conjugation of the anionic Cas9 ribonucleoprotein to cationic peptides would be associated with a hindered nuclease activity due to undesired electrostatic interactions. We here report a supramolecular strategy for the direct delivery of Cas9 by an amphiphilic penetrating peptide that was prepared by a hydrazone bond formation between a cationic peptide scaffold and a hydrophobic aldehyde tail. The peptide/protein non-covalent nanoparticles performed with similar efficiency and less toxicity than one of the best methods described to date. To the best of our knowledge this report constitutes the first supramolecular strategy for the direct delivery of Cas9 using a penetrating peptide vehicle. The results reported here confirmed that peptide amphiphilic vectors can deliver Cas9 in a single incubation step, with good efficiency and low toxicity. This work will encourage the search and development of conceptually new synthetic systems for transitory endonucleases direct delivery.

Two of the main types of nanotubular architectures are the single-walled carbon nanotubes (SWCNTs) and the self-assembling cyclic peptide nanotubes (SCPNs). We here report the preparation of the dual composite resulting from the ordered combination of both tubular motifs. In the resulting architecture, the SWCNTs can act as templates for the assembly of SCPNs that engage the carbon nanotubes noncovalently via pyrene "paddles", each member of the resulting hybrid stabilizing the other in aqueous solution. The particular hybrids obtained in the present study formed highly ordered oriented arrays and display complementary properties such as electrical conductivity. Furthermore, a self-sorting of the cyclic peptides toward semiconducting rather than metallic SWCNTs is also observed in the aqueous dispersions. It is envisaged that a broad range of exploitable properties may be achieved and/or controlled by varying the cyclic peptide components of similar SWCNT/SCPN hybrids.

A novel chemoselective one-pot transformation of acetals to silyl ethers is reported. Free hydroxyls, double bonds and triple bonds are unaffected in optimal reaction conditions. This practical, inexpensive protocol allows the selective replacement of acetal-forming protecting groups with silyl groups in a single step under mild conditions.

The lipid bilayer membranes are Nature's dynamic structural motifs that individualize cells and keep ions, proteins, biopolymers and metabolites confined in the appropriate location. The compartmentalization and isolation of these molecules from the external media facilitate the sophisticated functions and connections between the different biological processes accomplished by living organisms. However, cells require assistance from minimal energy shortcuts for the transport of molecules across membranes so that they can interact with the exterior and regulate their internal environments. Ion channels and pores stand out from all other possible transport mechanisms due to their high selectivity and efficiency in discriminating and transporting ions or molecules across membrane barriers. Nevertheless, the complexity of these smart "membrane holes" has driven researchers to develop simpler artificial structures with comparable performance to the natural systems. As a broad range of supramolecular interactions have emerged as efficient tools for the rational design and preparation of stable 3D superstructures, these results have stimulated the creativity of chemists to design synthetic mimics of natural active macromolecules and even to develop artificial structures with functions and properties. In this Account, we highlight results from our laboratories on the construction of artificial ion channel models that exploit the self-assembly of conformationally flat cyclic peptides (CPs) into supramolecular nanotubes. Because of the straightforward synthesis of the cyclic peptide monomers and the complete control over the internal diameter and external surface properties of the resulting hollow tubular suprastructure, CPs are the optimal candidates for the fabrication of ion channels. The ion channel activity and selective transport of small molecules by these structures are examples of the great potential that cyclic peptide nanotubes show for the construction of functional artificial transmembrane transporters. Our experience to date suggests that the next steps for achieving conceptual devices with better performance and selectivity will derive from the topological control over cyclic peptide assembly and the functionalization of the lumen.

We here describe the application of oxime bond formation between a peptide scaffold and different aldehydes to modify the transporting capabilities of penetrating peptides. We show that bonds such as oximes offer a great synthetic advantage for the modification of the properties of model penetrating peptides. We believe that this approach will allow the development of improved intracellular delivery vehicles This work was supported by the Spanish Ministry of Economy and Competitivity (MINECO) [CTQ2014-59646-R], the Xunta de Galicia (ED431G/09) and the ERDF. J.P. received an F.P.I. fellowship from MINECO. J.M. received a Ramon y Cajal (RYC-2013-13784) and an ERC Starting Investigator Grant (DYNAP-677786) SI

Gene transfection continues to be a major challenge in chemistry, biology and materials sciences. New methodologies and recent breakthroughs have renewed the interest in the discovery and development of new tools for efficient gene transfection. Hydrazone formation between a cationic head and hydrophobic tails has emerged as one of the most promising techniques for nucleotide delivery. In this contribution, we have exploited hydrazone formation to modulate the transfection activity of a parent linear peptide in combination with a plasmid DNA cargo. This strategy allowed the straightforward preparation, under physiologically compatible conditions, of a discrete library of amphiphilic modulated penetrating peptides. Without the requirement of any isolation or purification steps, these modulated amphiphilic peptides were combined with a plasmid DNA and screened in transfection experiments of human HeLa cells. Three of these hydrazone-conjugated peptides were identified as excellent vectors for plasmid delivery with comparable, or even higher, efficiencies and lower toxicity than the commercial reagents employed in routine transfection assays We are thankful to Dr. Irene Lostalé-Seijo for cell culture assistance and discussions. We acknowledge funding from the Spanish Government MINECO: [CTQ2014-59646-R] and [CTQ2015-74621-JIN], the Xunta de Galicia (ED431G/09), the ERDF and the CESGA. R. G.-F. received a FCT Investigator Grant from Portugal (IF/01133/2015). J.M. received a Ramon y Cajal (RYC-2013-13784) and an ERC Starting Investigator Grant (DYNAP-677786) SI

NOTICE: This is the peer reviewed version of the following article: Fuertes A, Juanes M, Granja J, Montenegro J. Supramolecular functional assemblies: dynamic membrane transporters and peptide nanotubular composites. Chem Commun. 2017;53(56):7861-7871. [doi: 10.1039/C7CC02997G]. This article may be used for non-commercial purposes in accordance with RSC Terms and Conditions for self-archiving The fabrication of functional molecular devices constitutes one of the most important current challenges for chemical sciences. The complex processes accomplished by living systems continuously demand the assistance of non-covalent interactions between molecular building blocks. Additionally, these building blocks (proteins, membranes, nucleotides) are also constituted by self-assembled structures. Therefore, supramolecular chemistry is the discipline required to understand the properties of the minimal self-assembled building blocks of living systems and to develop new functional smart materials. In the first part of this feature article, we highlight selected examples of the preparation of supramolecular membrane transporters with special emphasis in the application of dynamic covalent bonds. In the second section of the paper we review recent breakthroughs in the preparation of peptide nanotubes hybrids with functional applications. The development of these devices constitutes an exciting process from where we can learn how to understand and manipulate supramolecular functional assemblies We acknowledge funding from the Spanish Agencia Estatal de Investigación (AEI) (CTQ2014-59646-R and CTQ2016-78423-R), the Xunta de Galicia (ED431G/09 and 2016-AD031) and the ERDF. A. F. and M. J. received F. P. U. and F. P. I. fellowships from MECD and MINECO. J. M. received a Ramon y Cajal Grant (RYC-2013-13784), an ERC Starting Investigator Grant (DYNAP-677786) and a Young Investigator Grant from the Human Frontier Research Program (RGY0066/2017) SI

NOTICE: This is the peer reviewed version of the following article: Salvadó, I, Gamba, I, Montenegro J, Martínez-Costas J, Brea JM, Loza MI, Vázquez López M, Vázquez M.E. Membrane-disrupting iridium(III) oligocationic organometallopeptides. Chem. Commun., 2016,52, 11008-11011. DOI: 10.1039/C6CC05537K. This article may be used for non-commercial purposes in accordance with RSC Terms and Conditions for self-archiving A series of oligoarginine peptide derivatives containing cyclometallated iridium(III) units display remarkable cytotoxicity, comparable to that of cisplatin. In vitro studies with unilamellar vesicles support a membrane-disrupting mechanism of action We are thankful for the support given by the Spanish grants SAF2013-41943-R, CTQ2015-70698-R, CTQ2013-49317-EXP,CTQ2014-59646-R, and BFU2013-43513-R, and the Xunta de Galicia GRC2013-041. Support from COST Action CM1105 and the orfeo-cinqa network (CTQ2014-51912-REDC) is kindly acknowledged SI

An expeditious, highly efficient approach to 11-cis-retinoids was achieved by semihydrogenation of a readily available 11-yne precursor through a hydrosilylation-protodesilylation protocol. The complete chemo-, regio-, and syn-stereoselectivity of the method also allowed direct access to 11- and 12-monodeutero-, and 11,12-dideutero-11-cis-retinoids. The analogous trans series was not accessible by this route, and was synthesized by means of Hiyama coupling.

This paper presents a full account of the use of Hiyama cross-coupling reactions in a highly convergent approach to retinoids in which the key step is construction of the central C10-C11 bond. Representatives of two families of oxygen-activated dienyl silanes (ethoxysilanes and silanols) and of all reported families of "safety-catch" silanols (siletanes, silyl hydrides, allyl-, benzyl-, aryl-, 2-pyridyl- and 2-thienylsilanes) were regio- and stereoselectively prepared and stereospecifically coupled to an appropriate electrophile by treatment with a palladium catalyst and a nucleophilic activator. Both all-trans and 11-cis-retinoids, and their chain-demethylated analogues, were obtained in good yields regardless of the geometry (E/Z) and of the steric congestion in each fragment. This comprehensive study conclusively establishes the Hiyama cross-coupling reaction, with its mild reaction conditions and stable, easily prepared, ecologically advantageous silicon-based coupling partners, as the most effective route to retinoids reported to date.

The objective of this account is to summarize our recent progress with functional biosupramolecular systems concisely. The functions covered are artificial photosynthesis, anion transport, and sensing in lipid bilayer membranes. With artificial photosynthesis, the current emphasis is on the construction of ordered and oriented architectures on solid surfaces. Recent examples include the zipper assembly of photosystems with supramolecular n/p-heterojunctions and oriented antiparallel redox gradients. Current transport systems in lipid bilayers reveal new interactions at work. Examples include anion−macrodipole or anion−π interactions. Current attention with membrane-based sensing systems shifts from biosensor approaches with enzymatic signal generation to aptamers (i.e., the DNA version of immunosensing) and differential sensing with dynamic polyion−counterion transporters. The functional diversity accessible with biosupramolecular systems is highlighted, as is the critical importance of cross-fertilization at intertopical convergence zones.

The objective of this study was to introduce differential sensing techniques to synthetic systems that act, like olfactory receptors, as transporters in lipid bilayer membranes. Routine with most alternative chemosensing ensembles, pattern generation has, quite ironically, remained inaccessible in lipid bilayers because the number of available crossresponsive sensor components has been insufficient. To address this challenge, we here report on the use of cationic hydrazides that can react in situ with hydrophobic analytes to produce cationic amphiphiles which in turn can act as countercation activators for polyanionic transporters in fluorogenic vesicles. To expand the dimension of signals generated by this system, a small collection of small peptides containing a positive charge (guanidinium, ammonium) and one to three reactive hydrazides are prepared. Odorants are used as examples for hydrophobic analytes, perfumes to probe compatibility with complex matrices, and counterion-activated calf-thymus DNA as representative polyion–counterion transport system. Principal component and hierarchical cluster analysis of the obtained multidimensional patterns are shown to differentiate at least 21 analytes in a single score plot, discriminating also closely related structures such as enantiomers, cis–trans isomers, single-atom homologs, as well as all tested perfumes. Inverse detection provides access to analytes as small as acetone. The general nature of the introduced methodology promises to find diverse applications in current topics in biomembrane research.

The design, synthesis, and evaluation of small peptides with one to three negative charges and one to three hydrazides as key components of membrane-based synthetic sensing systems are reported. Their spontaneous reaction with hydrophobic aldehydes or ketones gives rapid access to small collections of amphiphilic anions. These anionic amphiphiles can activate polycations as anion transporters in lipid-bilayer membranes. Odorants are used as representative hydrophobic aldehydes and ketones, and cell-penetrating peptides (CPPs) as polycationic transporters in fluorogenic vesicles. Different activities obtained with different counterion activators are used to generate multidimensional patterns that can be recognized by principal component and hierarchical cluster analysis to extract unique “fingerprints” for individual analytes (including enantiomers, cis–trans isomers or perfumes as illustrative analyte mixtures). Comparison of the peptide activators reveals that carboxylates perform better than phosphonates. Gemini-like activators containing two carboxylates and two hydrophobic hydrazone tails are best, whereas excessive charges and tails give weaker activities. This result differs from cationic activators of polyanionic transporters such as DNA, which worked best with octopus amphiphiles with one cationic head and four hydrophobic tentacles.

We report the design, synthesis and evaluation of dynamic "octopus" amphiphiles with emphasis on their efficiency as activators in synthetic membrane-based sensing systems. Previously, we found that the in situ treatment of charged hydrazides with hydrophobic aldehydes or ketones gives amphiphilic counterion activators of polyion transporters in lipid bilayers, and that their efficiency increases with the number of their hydrophobic tails. Herein, we expand this series to amphiphiles with one cationic head (guanidinium or ammonium) and four exchangeable hydrophobic tails. These results, with the highest number of tails reported to date, confirm that dynamic octopus amphiphiles provide access to maximal activity and selectivity. Odorants, such as muscone, carvone, or anisaldehyde are used to outline their usefulness in differential sensing systems that operate based on counterion-activated DNA transporters in fluorogenic vesicles. The enhanced ability of octopus amphiphiles to enable the discrimination of enantiomers as well as that of otherwise intractable ortho, meta, and para isomers and short cyclo-/alkyl tails is demonstrated. These findings identify dynamic octopus amphiphiles as being promising for application to differential sensing, "fragrant" cellular uptake, and slow release.

The first application of the Hiyama reaction to the synthesis of retinoids is reported. A range of organosilicon moieties (siloxanes, silanols and three kinds of "safety-catch" silanols) were successfully coupled, under activation, to obtain trans-retinol or 11-cis-retinol with high yield and stereoselectivity. The advantageous properties of the silicon-based coupling partners and the mild reaction conditions firmly establish the Hiyama reaction as a viable (even superior) alternative to the traditional Suzuki and Stille couplings in the retinoid field.

Palytoxin (PLTX) is a lethal natural toxin often found in Palythoa zoantharians that, together with its congeners, may induce adverse effects in humans after inhalation of toxic aerosols both in open-air and domestic environments, namely in the vicinity of public and private aquaria. In this study, we describe a poisoning of an aquarium hobbyist who was hospitalized after handling a PLTXs-containing zoantharian hexacoral. Furthermore, we provide evidence for water detoxification. The zoantharian was morphologically and genetically identified as Palythoa cf. toxica (Cnidaria: Anthozoa). Palytoxin itself and two new PLTX congeners, a hydroxyPLTX and a deoxyPLTX, were detected and structurally identified by liquid chromatography high resolution multiple stage mass spectrometry (LC-HRMSn, n = 1, 2). Total and individual toxins were quantified by LC-HRMS and sandwich ELISA both in the zoantharian (93.4 and 96.80 μg/g, respectively) and in the transport water (48.3 and 42.56 μg/mL, respectively), with an excellent mean bias of 1.3% between the techniques. Activated carbon adsorbed 99.7% of PLTXs contained in the seawater and this represents a good strategy for preventing aquarium hobbyist poisonings.

NOTICE:This is the peer-reviewed version of the following article:Juan M. Priegue, Daniel N. Crisan, José Martínez-Costas, Juan R. Granja, Francisco Fernandez-Trillo, and Javier Montenegro (2016),“In situ Functionalized Polymers for siRNA Delivery ; Angew. Chem. Int. Ed., 55, 7492–7495 [doi: 10.1002/anie.201601441]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving A new method is reported herein for screening the biological activity of functional polymers across a consistent degree of polymerization and in situ, that is, under aqueous conditions and without purification/isolation of candidate polymers. In brief, the chemical functionality of a poly(acryloyl hydrazide) scaffold was activated under aqueous conditions using readily available aldehydes to obtain amphiphilic polymers. The transport activity of the resulting polymers can be evaluated in situ using model membranes and living cells without the need for tedious isolation and purification steps. This technology allowed the rapid identification of a supramolecular polymeric vector with excellent efficiency and reproducibility for the delivery of siRNA into human cells (HeLa-EGFP). The reported method constitutes a blueprint for the high-throughput screening and future discovery of new polymeric functional materials with important biological applications Royal Society. Grant Number: IE130688 Spanish Ministry of Economy and Competitiveness. Grant Numbers: CTQ2014-59646-R, CTQ2013-43264-R, BFU2013-43513-R Birmingham Science City European Regional Development Fund Royal Society. Grant Number: RG140273 University of Birmingham MEC MINECO ERC. Grant Number: DYNAP-677786 SI

A stereospecific synthesis of 11-cis-retinoids has as its key step the hitherto unexplored palladium-catalyzed cross-coupling of trans-trienyl electrophiles and (1Z,3E)-penta-1,3-dienyl boronates (a Suzuki-Miyaura reaction) or stannanes (a Stille reaction). This highly convergent approach constitutes the first application of cis-organometallic moieties to the synthesis of 11-cis-retinoids and represents a general, straightforward route to the visual chromophore.

The objective of this Feature Article is to reflect on the importance of established and emerging principles of supramolecular organic chemistry to address one of the most persistent problems in life sciences. The main topic is dynamic covalent chemistry on cell surfaces, particularly disulfide exchange for thiol-mediated uptake. Examples of boronate and hydrazone exchange are added for contrast, comparison and completion. Of equal importance are the discussions of proximity effects in polyions and counterion hopping, and more recent highlights on ring tension and ion pair–π interactions. These lessons from supramolecular organic chemistry apply to cell-penetrating peptides, particularly the origin of “arginine magic” and the “pyrenebutyrate trick,” and the currently emerging complementary “disulfide magic” with cell-penetrating poly(disulfide)s. They further extend to the voltage gating of neuronal potassium channels, gene transfection, and the delivery of siRNA. The collected examples illustrate that the input from conceptually innovative chemistry is essential to address the true challenges in biology beyond incremental progress and random screening.

N-Heteroaryl retinals derived from indole, 1-indolizine and 3-indolizine (10 a-c) have been synthesized after their UV/Vis red-shifted absorption properties had been predicted by time-dependent density functional theory (TD-DFT) computations. The three new analogues form artificial pigments upon recombination with bacterioopsin: indolyl retinal 10 a undergoes fast and efficient reconstitution to form a species with a UV/Vis absorbance maximum similar to that of wild-type bacteriorhodopsin, whilst the indolizinyl retinals 10 b and 10 c also reconstitute in significant proportion to give noticeably red-shifted, although unstable, pigments. Significant changes in the pK(a) values of these artificial bacteriorhodopsins are interpreted as arising from nonoptimal binding-site occupancy by the chromophore due to steric constraints.

The rapid transcriptional activation of cellular genes by either type 1 interferons (IFNalpha/beta) or type 2 interferon (IFNgamma) is responsible for many of the pleiotropic effects of these cytokines, including their antiviral, antigrowth, and immunomodulatory activities. Interferon-stimulated gene expression is mediated by transcription factors termed Stats, which upon being tyrosine-phosphorylated, translocate to the nucleus and bind enhancers of interferon-activated genes. We have recently characterized a new Jurkat cell variant, named H123, where IFNalpha stimulates programmed cell death. H123 clones that are resistant to the apoptotic actions of IFNalpha have been selected. One of these clones (Clone 8) is defective in its responses to IFNalpha with regard to activation of genes that require tyrosine phosphorylation of Stat2. Stimulation of Clone 8 cells with IFNalpha induces normal tyrosine phosphorylation of Stat1 and Stat3. Sequencing of Stat2 RNA reveals a substitution of proline 630 located within the Src homology 2 domain of Stat2 to leucine (P630L). Pro-630 and its adjacent amino acids are conserved in all Stat family members but are absent in other proteins that contain Src homology 2 domains. Expression of Stat2 P630L in cells inhibits IFNalpha-stimulated gene expression. These results not only define a critical motif in Stat2 required for its transcriptional activity, but they also provide evidence that resistance to type one IFNs can be mediated by mutations in Stat2 as well as those previously described for Stat1.

Aluminium trichloride catalyses the expeditious direct conversion of tetrahydropyranyl ethers to silyl ethers. This one-step transformation is chemoselective versus deprotection of the acetal and hydrosilylation of unsaturated carbon–carbon bonds, and can also be applied to linear acetals. A possible mechanism is tentatively proposed.

Pattern generation/recognition in lipid bilayers is introduced for the differentiation of anionic biological relevant polymers. The amplification of the polymer differences during transport events allows the straightforward identification of a wide range collection of anionic polymers. The introduced approach displays excellent resolution even for single mutations in short single-stranded oligonuclotides.

Dynamic amphiphiles are amphiphiles with dynamic covalent bridges between their hydrophilic heads and their hydrophobic tails. Their usefulness to activate ion transporters for odorant release and for differential sensing of odorants and perfumes has been demonstrated recently. Here we report that the same "fragrant" dynamic amphiphiles are ideal to screen for new siRNA transfection agents. The advantages of this approach include rapid access to fairly large libraries of complex structures and possible transformation en route to assist uptake and minimize toxicity. We report single component systems that exceed the best commercially available multicomponent cocktails with regard to both efficiency and velocity of EGFP knockdown in HeLa cells. In human primary fibroblasts siRNA mediated enzyme knockdown nearly doubled from >30 for Lipofectamine to >60 for our best hit. The identified structures were predictable neither from literature nor from results in fluorogenic vesicles and thus support the importance of conceptually innovative screening approaches. © 2013 American Chemical Society.