1D to 2D Self Assembly of Cyclic Peptides

Preparation and assembly of SiO2@TiO2 photoresponsive colloidal rings

We report the synthesis of SiO2 colloidal rings coated with TiO2, which enable photoresponsive self-assembly into porous ordered structures and hybrid assembly for the capture and release of non-active colloids in a hydrogen peroxide (H2O2) solution. Such assemblies originate from a concentration gradient generated by the TiO2-mediated decomposition of H2O2 under ultraviolet (UV) irradiation. The work provides a straightforward strategy to fabricate active colloids with ring-like shapes for the controlled assembly of open crystalline colloidal materials.

Colorimetry/fluorescence dual-signal sensing system based on peptide nanotubes activating hemin and PPIX for sensitive detection of tannic acid

Recently, it has become valuable to develop strategies based on multi-mode sensors to detect analytes related to human health, food safety and environmental pollution. In this study, KL@PPIX-hemin composite prepared by immobilizing hemin and protoporphyrin IX (PPIX) on self-assembled peptide nanotubes (PNTs) through multiple non-covalent interactions were used for colorimetric/fluorescent dual-mode sensing of tannic acid (TA). PNTs as a carrier can provide the hydrophobic microenvironment for hemin and PPIX to protect them from dimerization, thus activating their respective peroxidase-mimicking activity and fluorescence emission. Further experiments show that the composite could catalyze H2O2 to oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to generate blue ox-TMB, which could exactly quench the emission of PPIX by inner filter effect. The added TA can reduce ox-TMB to TMB and further turn on the fluorescence of system. A colorimetric/fluorescent dual-mode sensing system for TA was thus constructed and a low limit of detection (13.2 nM) was obtained. In addition, the analytical strategy has been successfully applied to accurate TA determination in actual tea samples. The method was also combined with smartphone to achieve visual detection of TA, which provides a broad prospect for portable and rapid tannic acid analysis.

Chirality Effects in Peptide-Based Dynamic Combinatorial Chemistry

Naturally occurring peptides are almost exclusively composed of L-amino acids, and the incorporation of D-amino acids can profoundly alter their ability to fold and self-assemble. Here we explore the effects of chirality on the formation of disulfide dynamic combinatorial libraries (DCLs) generated by short cysteine-rich peptides. Our findings consistently show that heterochiral tripeptides form more diverse DCLs than their homochiral counterparts. The most complex library appears to encompass all possible cyclic species up to 19mers. Given that each of these species exists as a mixture of parallel and antiparallel isomers, we estimate this library to contain a total of 2,045 distinct compounds-a remarkable result considering that the library generated by the analogous homochiral peptide predominantly contains two dimers. In certain situations, peptide chirality also affects the relative stability of parallel and antiparallel isomers. Taken together, these results show that small changes in peptide chirality can be dramatically amplified through the formation of cyclic species.

Supramolecular oral delivery technologies for polypeptide-based drugs

Oral supramolecular drug delivery systems (SDDSs) have shown promising potential, along with a rapid increase in the development of polypeptide-based drugs. Biofriendly, biocompatible, and multistimulation-responsive SDDSs achieve their unique deliverability via noncovalent bonds, which can encapsulate drugs and release them at the target site along the oral tract. In this review, we analyze the oral tract from an anatomical perspective and explain the potential physical, microenvironmental, and systematic barriers, as well as the properties of drug delivery. After understanding the specific environment at different oral sites, the application of SDDSs to the mouth, stomach, small intestine, and cell targeting is summarized. Finally, this review summarizes the application of SDDSs for the successful delivery of drugs and describes how to overcome the barriers of SDDSs in drug delivery using a more biofriendly approach.

Self-assembled nanotubes from the supramolecular polymerization of discrete cyclic entities

Inspired by the extraordinary attributes displayed by nanotubes in Nature, the creation of self-assembled nano-sized hollow tubes is an area of significant and growing interest given its potential application in transmembrane ion channels, ion sensing or catalysis, among others. One of the most utilized strategies employed to build these supramolecular entities implies the stacking of discrete cyclic units. Given the intrinsic dynamicity of the forces that drive the self-assembly processes, this approach offers substantial advantages when compared to inorganic or covalent approaches, ranging from tunable pore designs to error correction, to name a few. Herein we focus on the different approaches explored to design discrete cyclic entities as building blocks for the construction of self-assembled nanotubes, as well as the analytical tools used to elucidate the resulting structures. Attending to the nature of the bond involved in the formation of the cycle, we have distinguised three main categories: covalent, non-novalent and dynamic-covalent cycles. This review thus constitutes a roadmap to build self-assembled nanotubes based on soft matter and paves the way to expand their current applications.

Biomimetic Parallel Vein-like Two-Dimensional Supramolecular Layers Containing Embedded One-Dimensional Conduits Driven by Cation-π Interaction and Hydrogen Bonding to Promote Photocatalytic Hydrogen Evolution

Two-dimensional supramolecular assemblies (2DSAs) with well-defined nanostructures have emerged as promising candidates for diverse applications, particularly in photocatalysis. However, it still remains a significant challenge to simultaneously achieve effective electron transport and multiple active sites in 2DSA, even though this is crucial for enhancing photocatalytic performance. This reason can be attributed to the lack of a suitable structural paradigm that enables both effective intermolecular orbital overlap and increased substrate contact. Inspired by the parallel venation of monocotyledons that can facilitate substrate transfer, we overcome the limitation, in this study, by integrating parallel-arranged one-dimensional (1D) conduits with edge-on packing motifs to construct biomimetic, parallel vein-like two-dimensional supramolecular layers (PV-2DSLs) through the hierarchical self-assembly of cationically modified, rigid multiarmed monomers. The resulting PV-2DSLs exhibit a long-range aromatic cation-π stacking that can facilitate electron transport. Importantly, the unique structural feature of these PV-2DSLs is the orderly and parallel embedding of 1D conduits within the 2D plane, which is significantly different from the conventional channels formed by the vertical stacking of 2D porous materials. These conduits promote multielectron transfer pathways, leading to enhanced charge separation and carrier transport when coupled with long-range aromatic cation-π stacking. As a consequence, these PV-2DSLs exhibit long excited state lifetime, leading to significantly improved hydrogen production rates up to 3.5 mmol g-1 h-1, which is approximately 17.5 times higher than that of the counterpart without 1D conduits (0.2 mmol g-1 h-1).

Understanding the Role of Solvent Polarity and Amino Acid Composition of Cyclic Peptides in Nanotube Stability

Cyclic peptides (CPs) possess the ability to self-assemble into cyclic peptide nanotubes (CPNTs), which find extensive applications in nanotechnology. The formation and stability of these nanotubes are influenced by multiple factors. The present study explores the stability of CPNTs in various solvents with varying polarity, focusing on three specific peptide sequences: DK4, WL4, and DLKL2. Using molecular dynamics simulations, the effect of solvent polarity and peptide composition on the stability of CPNTs is assessed through the determination of electrostatic, van der Waals, and hydrogen-bonding interactions. The binding free energy between adjacent cyclic peptide rings is analyzed via MM/GBSA and MM/PBSA methods, revealing that DLKL2, an amphiphilic peptide, exhibits greater stability than DK4 and WL4 in nonpolar solvents. The introduction of leucine residues in DLKL2 reduces intramolecular hydrogen bonding and electrostatic interactions, promoting stronger interpeptide backbone hydrogen bonds and maintaining the nanotube's structural integrity. Hydrogen bond lifetimes, computed using the corresponding time correlation function, indicate the longest-lasting hydrogen bonds occur in all the solvent environments except water, further contributing to the stability of DLKL2 nanotubes. Additionally, deformation from circularity in the peptide rings, analyzed using ellipticity values, highlights the degree of structural distortion across solvents, with DK4 showing the highest deviation due to stronger intramolecular interactions. These findings offer valuable insights into the roles of solvent and peptide composition in the self-assembly and stability of CPNTs, which have significant implications for their potential applications in nanotechnology and biomedicine.

Electrospinning of Self-Assembling Oligopeptides into Nanofiber Mats: The Impact of Peptide Composition and End Groups

Low-molecular-weight oligopeptides can be electrospun into nanofiber mats. However, the mechanism underlying their electrospinnability is not well-understood. In this study, we used solid-phase peptide synthesis to produce the oligopeptide FFKK, to which the aromatic end-capping groups naphthalene, pyrene, and tetraphenylporphyrin were attached. Nuclear magnetic resonance, circular dichroism, and electrospray ionization mass spectrometry were used to characterize the oligopeptide structures. We investigated the effect of end-caps and oligopeptide concentration on their self-assembly as well as on their electrospinnability in fluorinated solvents. All oligopeptides with aromatic end-caps were amenable to electrospinning. Attenuated total reflectance Fourier transform infrared spectroscopy and microrheology results support the hypothesis that at sufficiently high concentrations, the self-assembled structures interact strongly, which facilitates electrospinning. Moreover, the results from this fundamental study can be extended to nonpeptidic small molecules possessing strong intermolecular interactions.

Understanding multicomponent low molecular weight gels from gelators to networks

BACKGROUND

The construction of gels from low molecular weight gelators (LMWG) has been extensively studied in the fields of bio-nanotechnology and other fields. However, the understanding gaps still prevent the prediction of LMWG from the full design of those gel systems. Gels with multicomponent become even more complicated because of the multiple interference effects coexist in the composite gel systems.

AIM OF REVIEW

This review emphasizes systems view on the understanding of multicomponent low molecular weight gels (MLMWGs), and summarizes recent progress on the construction of desired networks of MLMWGs, including self-sorting and co-assembly, as well as the challenges and approaches to understanding MLMWGs, with the hope that the opportunities from natural products and peptides can speed up the understanding process and close the gaps between the design and prediction of structures.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key concepts. Firstly, understanding the complicated multicomponent gels systems requires a systems perspective on MLMWGs. Secondly, several protocols can be applied to control self-sorting and co-assembly behaviors in those multicomponent gels system, including the certain complementary structures, chirality inducing and dynamic control. Thirdly, the discussion is anchored in challenges and strategies of understanding MLMWGs, and some examples are provided for the understanding of multicomponent gels constructed from small natural products and subtle designed short peptides.

Pathway-Dependent Catalytic Activity of Short-Peptide-Based Metallozyme: From Promiscuous Activity to Cascade Reaction

Many natural enzymes contain metal ions as cofactors in the active site for biological activity. However, the pathway of the introduction of metal ions in the earliest protein folds for the emergence of higher catalytic activity remains an intriguing open question. Herein, we demonstrate that pathway-dependent self-assembly of short-peptide-based metallozymes results in differences in catalytic activity. Short-peptide-based amyloids with solvent exposed arrays of colocalized catalytic units are able to bind highly soluble Cu2+ ions to demonstrate oxidase-like and RNase-like activity (promiscuity). Further, the metallozyme was able to exhibit higher hydrolase-oxidase cascade activity compared to the mixture of natural enzymes, esterase, and laccase. The collaboration between short-peptide-based amyloid microphases and metal ions suggests that metallozymes might have played a pivotal role in early metabolic processes and biopolymer evolution on the prebiotic earth.

Fabrication of Hierarchical Nanostructures Featuring Amplified Asymmetry Through Co-Assembly of Liquid Crystalline Block Copolymer and Chiral Amphiphiles

The widespread presence of hierarchical asymmetric structures in nature has sparked considerable interest because of their unique functionalities. These ingenious structures across multiple scales often emerge from the transfer and amplification of asymmetry from chiral molecules under various synergistic effects. However, constructing artificial chiral asymmetric structures, particularly in developing hierarchical multicomponent structures analogous to those formed in nature through synergistic non-covalent interactions, still presents tremendous challenges. Herein, we propose a co-assembly strategy to fabricate hierarchical chiral mesostructures by combining a liquid crystalline block copolymer (LC-BCP) with a small molecular amphiphile containing chiral alanine or phenylalanine as a linker. Through a classic solvent-exchange process, chiral amphiphiles embedded within LC-BCP finely regulate the LC ordering effect and facilitate transfer and amplification of asymmetry. Consequently, various co-assembled structures with significant hierarchical chirality features are obtained through synergetic effects. Remarkably, subtle alterations to the side groups of amino acids in the amphiphiles effectively adjust the hierarchical morphology transition. Moreover, the covalent bonding sequence of amino acids in the amphiphiles emerges as a critical factor governing the formation of hierarchical nanofibers and multilayered vesicles exhibiting a superhelical sense.

Peptide-based nanomaterials and their diverse applications

The supramolecular self-assembly of peptides offers a promising avenue for both materials science and biological applications. Peptides have garnered significant attention in molecular self-assembly, forming diverse nanostructures with α-helix, β-sheet, and random coil conformations. These self-assembly processes are primarily driven by the amphiphilic nature of peptides and stabilized by non-covalent interactions, leading to complex nanoarchitectures responsive to environmental stimuli. While extensively studied in biomedical applications, including drug delivery and tissue engineering, their potential applications in the fields of piezoresponsive materials, conducting materials, catalysis and energy harvesting remain underexplored. This review comprehensively elucidates the diverse material characteristics and applications of self-assembled peptides. We discuss the multi-stimuli-responsiveness of peptide self-assemblies and their roles as energy harvesters, catalysts, liquid crystalline materials, glass materials and contributors to electrical conductivity. Additionally, we address the challenges and present future perspectives associated with peptide nanomaterials. This review aims to provide insights into the versatile applications of peptide self-assemblies while concisely summarizing their well-established biomedical roles that have previously been extensively reviewed by various research groups, including our group.

Dynamic Peptide Nanoframework-Guided Protein Coassembly: Advancing Adhesion Performance with Hierarchical Structures

Hierarchical structures are essential in natural adhesion systems. Replicating these in synthetic adhesives is challenging due to intricate molecular mechanisms and multiscale processes. Here, we report three phosphorylated peptides featuring a hydrophobic self-assembly motif linked to a hydrophilic phosphorylated sequence (pSGSS), forming peptide fibril nanoframeworks. These nanoframeworks effectively coassemble with elastin-derived positively charged proteins (PCP), resulting in complex coacervate-based adhesives with hierarchical structures. Our method enables the controlled regulation of both cohesion and adhesion properties in the adhesives. Notably, the complex adhesives formed by the dityrosine-containing peptide and PCP demonstrate an exceptional interfacial adhesion strength of up to 30 MPa, outperforming most known supramolecular adhesives and rivaling cross-linked chemical adhesives. Additionally, these adhesives show promising biocompatibility and bioactivity, making them suitable for applications such as visceral hemostasis and tissue repair. Our findings highlight the utility of bioinspired hierarchical assembly combined with bioengineering techniques in advancing biomedical adhesives.

Ordered Photoexfoliation for Polypseudorotaxane Nanosheets

Two-dimensional layered structural materials exhibit a wide range of properties due to their ultrahigh specific surface area. However, achieving ordered exfoliation to obtain uniform two-dimensional structures remains challenging. In this study, we developed a supramolecular system by covalently bonding hexathiobenzene (HB) into β-cyclodextrin to create a light-responsive moiety, followed by coassembly with bipyridine and nickel ions to form a polypseudorotaxane (PR) system, which enables an in situ light-induced exfoliation strategy for two-dimensional materials. By further introducing an appropriate ratio of ethanol and applying in situ light irradiation, the gradual evaporation of the solvent ultimately led to the uniform formation of bilayer PR two-dimensional materials. This strategy provides a novel and effective approach for the preparation of two-dimensional layered structural materials from the light perspective.

Two-Dimensional Supramolecular Polymorphism in Cyanine H- and J-Aggregates

We designed a new cyanine dye 1, with two pedant rod-like groups, capable of forming two distinct two-dimensional (2D) supramolecular polymorphs in methylcyclohexane; an H-type aggregate (Agg-H2) and a J-type aggregate (Agg-J). Importantly, these two polymorphs were not accessed through polymerization events, and instead through the thermal transformation of a third particle-like polymorph (Agg-H1) formed by the anti-cooperative assembly of 1. While Agg-H2 is generated upon cooling the solution of Agg-H1 by a thermoreversible polymorph transition, the Agg-J was obtained through a hidden pathway by combining sonication and cooling to the Agg-H1 solution. This is the first report on the obtention of H- and J-type cyanine polymorphs that in turn could be isolated in solid-state to render two new 2D photoactive materials. This paper unveils new strategies for designing 2D supramolecular polymers using calamitic residues, but also undercovers relevant aspects of pathway complexity and polymorph transitions that might be crucial for developing novel photonic systems.

Tailored peptide nanomaterials for receptor targeted prostate cancer imaging

We report the development of a peptide-based optical nanoprobe specifically tailored for prostate cancer imaging. The imaging probe is comprised of cyclic peptide nanotubes, formed via the aqueous co-assembly of four cyclic D,L-alternating octapeptides. The inherent properties of these cyclic building blocks have been carefully selected to enhance their efficacy in imaging applications, through the addition of a cancer targeting peptide and a fluorescent dye. Comprehensive characterization using scanning electron microscopy (FESEM) and low-voltage transmission electron microscopy (LV-TEM) confirms the formation of nanotubes through co-assembly of the cyclic peptides. The resulting nanotubes show an average diameter of 28 nm. Circular dichroism (CD) spectroscopy validates the formation of stable beta-sheet hydrogen bonding structures at both 20 and 37 °C, ensuring their suitability for biomedical applications. Evaluation of PSMA-binding specificity of the resulting peptide nanotubes is assessed using confocal fluorescence microscopy demonstrating receptor-mediated uptake in prostate cancer cells. We anticipate this strategy will provide the basis for the utilization of co-assembled systems for advancing molecular imaging techniques in prostate cancer and other cancers.

The structural and functional impacts of rationally designed cyclic peptides on self-assembly-mediated functionality

Compared with their linear counterparts, cyclic peptides, characterized by their unique topologies, offer superior stability and enhanced functionality. In this review article, the rational design of cyclic peptide primary structures and their significant influence on self-assembly processes and functional capabilities are comprehensively reviewed. We emphasize how strategically modifying amino acid sequences and ring sizes critically dictate the formation and properties of peptide nanotubes (PNTs) and complex assemblies, such as rotaxanes. Adjusting the number of amino acid residues and side chains allows researchers to tailor the diameter, surface properties, and functions of PNTs precisely. In addition, we discuss the complex host-guest chemistry of cyclic peptides and their ability to form rotaxanes, highlighting their potential in the development of mechanically interlocked structures with novel functionalities. Moreover, the critical role of computational methods for accurately predicting the solution structures of cyclic peptides is also highlighted, as it enables the design of novel peptides with tailored properties for a range of applications. These insights set the stage for groundbreaking advances in nanotechnology, drug delivery, and materials science, driven by the strategic design of cyclic peptide primary structures.

Liquid Crystal Behavior of Uniform Short Rods Made from Computationally Designed Parallel Coiled Coil Building Blocks

Parallel, homotetrameric coiled coils were computationally designed using 29 amino acid peptides. These parallel coiled coils, called "bundlemers", have C2 symmetry, with all N-termini displayed from one end of the nanoparticle and all C-termini from the opposite end. This anisotropic display of the peptide termini allowed for the functionalization of two sets of nanoparticles with either maleimide or thiol functionality at the N-terminal region of the constituent peptides. The thiol-Michael conjugation reaction between the N-terminal end of complementary bundlemer nanoparticles formed monodisperse, rigid bundlemer dimer, called "dibundlemer", rods. The constituent, individual bundlemer nanoparticles were characterized with small-angle X-ray scattering (SAXS), Förster resonance energy transfer (FRET), and circular dichroism (CD) spectroscopy to confirm the parallel assembly of the coiled coils, consistent with the computational design. The dibundlemer rods were characterized with SAXS to reveal the uniform dibundlemer nature of the rods. Optical birefringence is observed in concentrated samples of the rods, with polarized optical microscopy (POM) revealing a nematic liquid crystalline behavior.

Coiled Coil Peptide Tiles (CCPTs): Expanding the Peptide Building Block Design with Multivalent Peptide Macrocycles

Owing to their synthetic accessibility and protein-mimetic features, peptides represent an attractive biomolecular building block for the fabrication of artificial biomimetic materials with emergent properties and functions. Here, we expand the peptide building block design space through unveiling the design, synthesis, and characterization of novel, multivalent peptide macrocycles (96mers), termed coiled coil peptide tiles (CCPTs). CCPTs comprise multiple orthogonal coiled coil peptide domains that are separated by flexible linkers. The constraints, imposed by cyclization, confer CCPTs with the ability to direct programmable, multidirectional interactions between coiled coil-forming "edge" domains of CCPTs and their free peptide binding partners. These fully synthetic constructs are assembled using a convergent synthetic strategy via a combination of native chemical ligation and Sortase A-mediated cyclization. Circular dichroism (CD) studies reveal the increased helical stability associated with cyclization and subsequent coiled coil formation along the CCPT edges. Size-exclusion chromatography (SEC), analytical high-performance liquid chromatography (HPLC), and fluorescence quenching assays provide a comprehensive biophysical characterization of various assembled CCPT complexes and confirm the orthogonal colocalization between coiled coil domains within CCPTs and their designed on-target free peptide partners. Lastly, we employ molecular dynamics (MD) simulations, which provide molecular-level insights into experimental results, as a supporting method for understanding the structural dynamics of CCPTs and their complexes. MD analysis of the simulated CCPT architectures reveals the rigidification and expansion of CCPTs upon complexation, i.e., coiled coil formation with their designed binding partners, and provides insights for guiding the designs of future generations of CCPTs. The addition of CCPTs into the repertoire of coiled coil-based building blocks has the potential for expanding the coiled coil assembly landscape by unlocking new topologies having designable intermolecular interfaces.

Incorporation of phenylcarbonyl groups in the sidechain: A tool to induce ordered assembly of peptides on surfaces

The possibility of introducing various functionalities on peptides with relative ease allows them to be used for molecular applications. However, oligopeptides prepared entirely from proteinogenic amino acids seldom assemble as ordered structures on surfaces. Therefore, sidechain modifications of peptides that can increase the intermolecular interactions without altering the constitution of a given peptide become an attractive route to self-assembling them on surfaces. We find that replacing phenylalanine residues with unusual amino acids that have phenylcarbonyl sidechains in oligopeptides increases the formation of ordered self-assembly on a highly ordered pyrolytic graphite surface. Peptides containing the modified amino acids provided extended long-range ordered assemblies, while the analogous peptides containing phenylalanine residues failed to form long-range assemblies. X-ray crystallographic analysis of the bulk structures of these peptides and the analogous peptides containing phenylalanine residues reveal that such modifications do not alter the secondary structure in crystals. It also reveals that the secondary hydrogen bonding interaction through phenylcarbonyl sidechains facilitates extended growth of the peptides on graphite.

Dissipative Self-Assembly of Patchy Particles under Nonequilibrium Drive: A Computational Study

Inspired by biology and implemented using nanotechnology, the self-assembly of patchy particles has emerged as a pivotal mechanism for constructing complex structures that mimic natural systems with diverse functionalities. Here, we explore the dissipative self-assembly of patchy particles under nonequilibrium conditions, with the aim of overcoming the constraints imposed by equilibrium assembly. Utilizing extensive Monte Carlo (MC) and Molecular Dynamics (MD) simulations, we provide insight into the effects of external forces that mirror natural and chemical processes on the assembly rates and the stability of the resulting assemblies comprising 8, 10, and 13 patchy particles. Implemented by a favorable bond-promoting drive in MC or a pulsed square wave potential in MD, our simulations reveal the role these external drives play in accelerating assembly kinetics and enhancing structural stability, evidenced by a decrease in the time to first assembly and an increase in the duration the system remains in an assembled state. Through the analysis of an order parameter, entropy production, bond dynamics, and interparticle forces, we unravel the underlying mechanisms driving these advancements. We also validated our key findings by simulating a larger system of 100 patchy particles. Our comprehensive results not only shed light on the impact of external stimuli on self-assembly processes but also open a promising pathway for expanding the application by leveraging patchy particles for novel nanostructures.

Exploring Macroscopic Dipoles of Designed Cyclic Peptide Ordered Assemblies to Harvest Piezoelectric Properties

Crystalline materials exhibiting non-centrosymmetry and possessing substantial surface dipole moments play a critical role in piezoelectricity. Designing biocompatible self-assembled materials with these attributes is particularly challenging when compared to inorganic materials and ceramics. In this study, we elucidate the crystal conformations of novel cyclic peptides that exhibit self-assembly into tubular structures characterized by unidirectional hydrogen bonding and piezoelectric properties. Unlike cyclic peptides derived from alternating L- and D-amino acids, those derived from new δ-amino acids demonstrate the formation of self-assembled tubes with unidirectional hydrogen bonds. Further, the tightly packed tubular assemblies and higher macrodipole moments result in superior piezoelectric coefficients compared to peptides with lower macrodipole moments. Our findings underscore the potential for designing cyclic peptides with unidirectional hydrogen bonds, thereby paving the way for their application in design of biocompatible piezo- and ferroelectric materials.

Driven Self-Assembly of Patchy Particles Overcoming Equilibrium Limitations

Bridging biological complexity and synthetic material design, we investigate dissipative self-assembly in patchy particle systems. Utilizing Monte Carlo and Molecular Dynamics simulations, we demonstrate how external driving forces mitigate equilibrium trade-offs between assembly time and structural stability, traditionally encountered in self-assembly processes. Our findings also extend to biological-mimicking environments, where we explore the dynamics of patchy particles under crowded conditions. This comprehensive analysis offers insights into advanced material design, opening avenues for innovations in nanotechnology applications.

Complex Pathways Drive Pluripotent Fmoc-Leucine Self-Assemblies

Nature uses complex self-assembly pathways to access distinct functional non-equilibrium self-assemblies. This remarkable ability to steer same set of biomolecules into different self-assembly states is done by avoiding thermodynamic pit. In synthetic systems, on demand control over 'Pathway Complexity' to access self-assemblies different from equilibrium structures remains challenging. Here we show versatile non-equilibrium assemblies of the same monomer via alternate assembly pathways. The assemblies nucleate using non-classical or classical nucleation routes into distinct metastable (transient hydrogels), kinetic (stable hydrogels) and thermodynamic structures [(poly)-crystals and 2D sheets]. Initial chemical and thermal inputs force the monomers to follow different assembly pathways and form soft-materials with distinct molecular arrangements than at equilibrium. In many cases, equilibrium structures act as thermodynamic sink which consume monomers from metastable structures giving transiently formed materials. This dynamics can be tuned chemically or thermally to slow down the dissolution of transient hydrogel, or skip the intermediate hydrogel altogether to reach final equilibrium assemblies. If required this metastable state can be kinetically trapped to give strong hydrogel stable over days. This method to control different self-assembly states can find potential use in similar biomimetic systems to access new materials for various applications.

Emerging chiral two-dimensional materials

Research into 2D materials has been growing with impressive speed since the discovery of graphene. Such layered materials with ultrathin morphologies and extreme aspect ratios currently display a vast range of properties; however, until recently a conspicuously missing property of 2D materials was global chirality. The situation has changed over the past few years with the implementation of several distinct types of ultrathin chiral 2D crystals. Here we offer a forward-looking perspective on this field to comprehend the fundamentals of global chirality in two dimensions and develop new directions. We specifically discuss the experimental achievements of the emerging chiral 2D materials with a focus on their design strategy, synthesis, structural characterization, fundamental physical properties and possible applications. We will highlight how the molecular-scale local chirality could be significantly transmitted and amplified throughout ultrathin single-crystalline 2D structures, resulting in distinctive global chirality that brings more sophisticated functions.

Multi-Responsive Peptide-Based Ultrathin Nanosheets Prepared by a Horizontal Monolayer Assembly

In this study, peptide-based self-assembled nanosheets with a thickness of approximately 1 nm were prepared using a hierarchical covalent physical fabrication strategy. The covalent alternating polymerization of helical peptide E3 with an azobenzene (AZO) structure yielded copolymers CoP(E3-AZO), which physically self-assembled into ultrathin nanosheets in an unanticipated two-dimensional horizontal monolayer arrangement. This special monolayer arrangement enabled the thickness of the nanosheets to be equal to the cross-sectional diameter of a single linear copolymer, which is a rare phenomenon. Molecular dynamics simulations suggested that the synergistic effect of multiple molecular interactions drives the self-assembly of CoP(E3-AZO) into nanosheets and that various methods, including phototreatment, pH adjustment, the addition of additives, and introduction of cosolvents, can alter the molecular interactions and modulate the self-assembly of CoP(E3-AZO), yielding diverse nanostructures. Remarkably, the ultrathin nanosheets selectively inhibited cancer cells at certain concentrations.

Advances in self-assembled nanotechnology in tumor therapy

The emergence of nanotechnology has opened up a new way for tumor therapy. Among them, self-assembled nanotechnology has received extensive attention in medicine due to its simple preparation process, high drug-loading capacity, low toxicity, and low cost. This review mainly summarizes the preparation methods of self-assembled nano-delivery systems, as well as the self-assembled mechanism of carrier-free nanomedicine, polymer-carried nanomedicine, polypeptide, and metal drugs, and their applications in tumor therapy. In addition, we discuss the advantages and disadvantages, future challenges, and opportunities of these self-assembled nanomedicines, which provide important references for the development and application of self-assembled nanotechnology in the field of medical therapy.

Designing Multifunctional Biomaterials via Protein Self-Assembly

Protein self-assembly is a fundamental biological process where proteins spontaneously organize into complex and functional structures without external direction. This process is crucial for the formation of various biological functionalities. However, when protein self-assembly fails, it can trigger the development of multiple disorders, thus making understanding this phenomenon extremely important. Up until recently, protein self-assembly has been solely linked either to biological function or malfunction; however, in the past decade or two it has also been found to hold promising potential as an alternative route for fabricating materials for biomedical applications. It is therefore necessary and timely to summarize the key aspects of protein self-assembly: how the protein structure and self-assembly conditions (chemical environments, kinetics, and the physicochemical characteristics of protein complexes) can be utilized to design biomaterials. This minireview focuses on the basic concepts of forming supramolecular structures, and the existing routes for modifications. We then compare the applicability of different approaches, including compartmentalization and self-assembly monitoring. Finally, based on the cutting-edge progress made during the last years, we summarize the current knowledge about tailoring a final function by introducing changes in self-assembly and link it to biomaterials' performance.

A Chirally Locked Bis-perylene Diimide Macrocycle: Consequences for Chiral Self-Assembly and Circularly Polarized Luminescence

Macrocycles containing chiral organic dyes are highly valuable for the development of supramolecular circularly polarized luminescent (CPL) materials, where a preorganized chiral framework is conducive to directing π-π self-assembly and delivering a strong and persistent CPL signal. Here, perylene diimides (PDIs) are an excellent choice for the organic dye component because, alongside their tunable photophysical and self-assembly properties, functionalization of the PDI's core yields a twisted, chiral π-system, capable of CPL. However, configurationally stable PDI-based macrocycles are rare, and those that are also capable of π-π self-assembly beyond dimers are unprecedented, both of which are advantageous for robust self-assembled chiroptical materials. In this work, we report the first bay-connected bis-PDI macrocycle that is configurationally stable (ΔG⧧ > 155 kJ mol-1). We use this chirally locked macrocycle to uncover new knowledge of chiral PDI self-assembly and to perform new quantitative CPL imaging of the resulting single-crystal materials. As such, we discover that the chirality of a 1,7-disubstituted PDI provides a rational route to designing H-, J- and concomitant H- and J-type self-assembled materials, important arrangements for optimizing (chir)optical and charge/energy transport properties. Indeed, we reveal that CPL is amplified in the single crystals of our chiral macrocycle by quantifying the degree of emitted light circular polarization from such materials for the first time using CPL-Laser Scanning Confocal Microscopy.

A method for in situ self-assembly of the catalytic peptide in enzymatic compartments of glucan particles

Drawing inspiration from cellular compartmentalization, enzymatic compartments play a pivotal role in bringing enzymes and substrates into confined environments, offering heightened catalytic efficiency and prolonged enzyme lifespan. Previously, we engineered bioinspired enzymatic compartments, denoted as TPE-Q18H@GPs, achieved through the spatiotemporally controllable self-assembly of the catalytic peptide TPE-Q18H within hollow porous glucan particles (GPs). This design strategy allows substrates and products to freely traverse, while retaining enzymatic aggregations. The confined environment led to the formation of catalytic nanofibers, resulting in enhanced substrate binding affinity and a more than two-fold increase in the second-order kinetic constant (kcat/Km) compared to TPE-Q18H nanofibers in a dispersed system. In this work, we will introduce how to synthesize the above-mentioned enzymatic compartments using salt-responsive catalytic peptides and GPs.

Peptide-Mediated Nanocarriers for Targeted Drug Delivery: Developments and Strategies

Effective drug delivery is essential for cancer treatment. Drug delivery systems, which can be tailored to targeted transport and integrated tumor therapy, are vital in improving the efficiency of cancer treatment. Peptides play a significant role in various biological and physiological functions and offer high design flexibility, excellent biocompatibility, adjustable morphology, and biodegradability, making them promising candidates for drug delivery. This paper reviews peptide-mediated drug delivery systems, focusing on self-assembled peptides and peptide-drug conjugates. It discusses the mechanisms and structural control of self-assembled peptides, the varieties and roles of peptide-drug conjugates, and strategies to augment peptide stability. The review concludes by addressing challenges and future directions.

Peptide Stereochemistry Effects from pKa-Shift to Gold Nanoparticle Templating in a Supramolecular Hydrogel

The divergent supramolecular behavior of a series of tripeptide stereoisomers was elucidated through spectroscopic, microscopic, crystallographic, and computational techniques. Only two epimers were able to effectively self-organize into amphipathic structures, leading to supramolecular hydrogels or crystals, respectively. Despite the similarity between the two peptides' turn conformations, stereoconfiguration led to different abilities to engage in intramolecular hydrogen bonding. Self-assembly further shifted the pKa value of the C-terminal side chain. As a result, across the pH range 4-6, only one epimer predominated sufficiently as a zwitterion to reach the critical molar fraction, allowing gelation. By contrast, the differing pKa values and higher dipole moment of the other epimer favored crystallization. The four stereoisomers were further tested for gold nanoparticle (AuNP) formation, with the supramolecular hydrogel being the key to control and stabilize AuNPs, yielding a nanocomposite that catalyzed the photodegradation of a dye. Importantly, the AuNP formation occurred without the use of reductants other than the peptide, and the redox chemistry was investigated by LC-MS, NMR, and infrared scattering-type near field optical microscopy (IR s-SNOM). This study provides important insights for the rational design of simple peptides as minimalistic and green building blocks for functional nanocomposites.

Bioinspired Amino Acid Based Materials in Bionanotechnology: From Minimalistic Building Blocks and Assembly Mechanism to Applications

Inspired by natural hierarchical self-assembly of proteins and peptides, amino acids, as the basic building units, have been shown to self-assemble to form highly ordered structures through supramolecular interactions. The fabrication of functional biomaterials comprised of extremely simple biomolecules has gained increasing interest due to the advantages of biocompatibility, easy functionalization, and structural modularity. In particular, amino acid based assemblies have shown attractive physical characteristics for various bionanotechnology applications. Herein, we propose a review paper to summarize the design strategies as well as research advances of amino acid based supramolecular assemblies as smart functional materials. We first briefly introduce bioinspired reductionist design strategies and assembly mechanism for amino acid based molecular assembly materials through noncovalent interactions in condensed states, including self-assembly, metal ion mediated coordination assembly, and coassembly. In the following part, we provide an overview of the properties and functions of amino acid based materials toward applications in nanotechnology and biomedicine. Finally, we give an overview of the remaining challenges and future perspectives on the fabrication of amino acid based supramolecular biomaterials with desired properties. We believe that this review will promote the prosperous development of innovative bioinspired functional materials formed by minimalistic building blocks.

Self-assembly of cyclic peptide monolayers by hydrophobic supramolecular hinges

Supramolecular polymerisation of two-dimensional (2D) materials requires monomers with non-covalent binding motifs that can control the directionality of both dimensions of growth. A tug of war between these propagation forces can bias polymerisation in either direction, ultimately determining the structure and properties of the final 2D ensemble. Deconvolution of the assembly dynamics of 2D supramolecular systems has been widely overlooked, making monomer design largely empirical. It is thus key to define new design principles for suitable monomers that allow the control of the direction and the dynamics of two-dimensional self-assembled architectures. Here, we investigate the sequential assembly mechanism of new monolayer architectures of cyclic peptide nanotubes by computational simulations and synthesised peptide sequences with selected mutations. Rationally designed cyclic peptide scaffolds are shown to undergo hierarchical self-assembly and afford monolayers of supramolecular nanotubes. The particular geometry, the rigidity and the planar conformation of cyclic peptides of alternating chirality allow the orthogonal orientation of hydrophobic domains that define lateral supramolecular contacts, and ultimately direct the propagation of the monolayers of peptide nanotubes. A flexible 'tryptophan hinge' at the hydrophobic interface was found to allow lateral dynamic interactions between cyclic peptides and thus maintain the stability of the tubular monolayer structure. These results unfold the potential of cyclic peptide scaffolds for the rational design of supramolecular polymerisation processes and hierarchical self-assembly across the different dimensions of space.

Two-Dimensional Supramolecular Polymerization of a Bis-Urea Macrocycle into a Brick-Like Hydrogen-Bonded Network

We report on a dendronized bis-urea macrocycle 1 self-assembling via a cooperative mechanism into two-dimensional (2D) nanosheets formed solely by alternated urea-urea hydrogen bonding interactions. The pure macrocycle self-assembles in bulk into one-dimensional liquid-crystalline columnar phases. In contrast, its self-assembly mode drastically changes in CHCl3 or tetrachloroethane, leading to 2D hydrogen-bonded networks. Theoretical calculations, complemented by previously reported crystalline structures, indicate that the 2D assembly is formed by a brick-like hydrogen bonding pattern between bis-urea macrocycles. This assembly is promoted by the swelling of the trisdodecyloxyphenyl groups upon solvation, which frustrates, due to steric effects, the formation of the thermodynamically more stable columnar macrocycle stacks. This work proposes a new design strategy to access 2D supramolecular polymers by means of a single non-covalent interaction motif, which is of great interest for materials development.

Recent Advances in the Development of Biomimetic Materials

In this review, we focused on recent efforts in the design and development of materials with biomimetic properties. Innovative methods promise to emulate cell microenvironments and tissue functions, but many aspects regarding cellular communication, motility, and responsiveness remain to be explained. We photographed the state-of-the-art advancements in biomimetics, and discussed the complexity of a "bottom-up" artificial construction of living systems, with particular highlights on hydrogels, collagen-based composites, surface modifications, and three-dimensional (3D) bioprinting applications. Fast-paced 3D printing and artificial intelligence, nevertheless, collide with reality: How difficult can it be to build reproducible biomimetic materials at a real scale in line with the complexity of living systems? Nowadays, science is in urgent need of bioengineering technologies for the practical use of bioinspired and biomimetics for medicine and clinics.

Dual enzyme-powered chemotactic cross β amyloid based functional nanomotors

Nanomotor chassis constructed from biological precursors and powered by biocatalytic transformations can offer important applications in the future, specifically in emergent biomedical techniques. Herein, cross β amyloid peptide-based nanomotors (amylobots) were prepared from short amyloid peptides. Owing to their remarkable binding capabilities, these soft constructs are able to host dedicated enzymes to catalyze orthogonal substrates for motility and navigation. Urease helps in powering the self-diffusiophoretic motion, while cytochrome C helps in providing navigation control. Supported by the simulation model, the design principle demonstrates the utilization of two distinct transport behaviours for two different types of enzymes, firstly enhanced diffusivity of urease with increasing fuel (urea) concentration and secondly, chemotactic motility of cytochrome C towards its substrate (pyrogallol). Dual catalytic engines allow the amylobots to be utilized for enhanced catalysis in organic solvent and can thus complement the technological applications of enzymes.

Dynamic Control of Cyclic Peptide Assembly to Form Higher-Order Assemblies

Chirality correction, asymmetry, ring-chain tautomerism and hierarchical assemblies are fundamental phenomena in nature. They are geometrically related and may impact the biological roles of a protein or other supermolecules. It is challenging to study those behaviors within an artificial system due to the complexity of displaying these features. Herein, we design an alternating D,L peptide to recreate and validate the naturally occurring chirality inversion prior to cyclization in water. The resulting asymmetrical cyclic peptide containing a 4-imidazolidinone ring provides an excellent platform to study the ring-chain tautomerism, thermostability and dynamic assembly of the nanostructures. Different from traditional cyclic D,L peptides, the formation of 4-imidazolidinone promotes the formation of intertwined nanostructures. Analysis of the nanostructures confirmed the left-handedness, representing chirality induced self-assembly. This proves that a rationally designed peptide can mimic multiple natural phenomena and could promote the development of functional biomaterials, catalysts, antibiotics, and supermolecules.

Uncovering the mechanisms of cyclic peptide self-assembly in membranes with the chirality-aware MA(R/S)TINI forcefield

Cyclic peptides (CPs) formed by alternation of D- and L-amino acids (D,L-CPs) can self-assemble into nanotubes (SCPNs) by parallel or/and antiparallel stacking. Different applications have been attributed to these nanotubes, including the disruption of lipid bilayers of specific compositions and the selective transport of ions throughout membranes. Molecular dynamics (MD) simulations have significantly contributed to understand the interaction between CPs, including the structural, dynamic and transport properties of their supramolecular aggregates. The high computational cost of atomic resolution forcefields makes them impractical for simulating the self-assembly of macromolecules, so coarse-grained (CG) models might represent a more feasible solution for this purpose. However, general CG models used for the simulation of biomolecules such as the MARTINI forcefield do not explicitly consider the non-covalent interactions leading to the formation of secondary structure patterns in proteins. This becomes particularly important in the case of CPs due to the D- and L-chirality alternation in their sequence, leading to opposite orientations of the backbone polar groups on both sides of the cyclic ring plane. In order to overcome this limitation, we have extended the MARTINI forcefield to introduce chirality in each residue of the CPs. The new parametrization, which we have called MA(R/S)TINI, reproduces the expected self-assembly patterns for several CP sequences in the presence of different membrane models, explicitly considering the chirality of the CPs and with no significant extra computational cost. Our simulations provide new mechanistic information of how these systems self-assemble in presence of different lipid scenarios, showing that the CP-CP and CP-membrane interactions are sensitive to the peptide sequence chirality. This opens the door to design new bioactive CPs based on CG-MD simulations. A web-based tool for the automatic parameterization of new CP sequences using MA(R/S)TINI, among other functionalities, is under construction (see http://cyclopep.com).

Multistep, site-selective noncovalent synthesis of two-dimensional block supramolecular polymers

Although the principles of noncovalent bonding are well understood and form the basis for the syntheses of many intricate supramolecular structures, supramolecular noncovalent synthesis cannot yet achieve the levels of precision and complexity that are attainable in organic and/or macromolecular covalent synthesis. Here we show the stepwise synthesis of block supramolecular polymers from metal-porphyrin derivatives (in which the metal centre is Zn, Cu or Ni) functionalized with fluorinated alkyl chains. These monomers first undergo a one-dimensional supramolecular polymerization and cyclization process to form a toroidal structure. Subsequently, successive secondary nucleation, elongation and cyclization steps result in two-dimensional assemblies with concentric toroidal morphologies. The site selectivity endowed by the fluorinated chains, reminiscent of regioselectivity in covalent synthesis, enables the precise control of the compositions and sequences of the supramolecular structures, as demonstrated by the synthesis of several triblock supramolecular terpolymers.

Triple Thorpe-Ingold Effect in the Synthesis of 18-Membered C3 Symmetric Lactams Stacking as Endless Supramolecular Tubes

Three C₃ symmetric macrolactams were very efficiently cyclized from their linear precursors. Adequately located substituents are responsible for the enhancement of reactivity that is not observed in the unsubstituted parent. DFT calculations show that the properly folded cyclization precursor, the reactive conformer, is more populated than other conformers, leading to a decrease of free energy of activation. The crystal structure of the ring substituted with three very bulky esters indicates that tubular stacking is preserved.

Two-Dimensional Peptide Assembly via Arene-Perfluoroarene Interactions for Proliferation and Differentiation of Myoblasts

Supramolecular assembly based on aromatic interactions can provide well-defined nanostructures with an understanding of intermolecular interactions at the molecular level. The peptide assembly via a supramolecular approach can overcome the inherent limitations of bioactive peptides, such as proteolytic degradations and rapid internalizations into the cytosol. Although extensive research has been carried out on supramolecular peptide materials with a two-dimensional (2D) structure, more needs to be reported on biological activity studies using well-defined 2D peptide materials. Physical and chemical properties of the 2D peptide assembly attributed to their large surface area and flexibility can show low cytotoxicity, enhanced molecular loading, and higher bioconjugation efficiency in biological applications. Here, we report supramolecular 2D materials based on the pyrene-grafted amphiphilic peptide, which contains a peptide sequence (Asp-Gly-Glu-Ala; DGEA) that is reported to bind to the integrin α2β1 receptor in 2D cell membranes. The addition of octafluoronaphthalene (OFN) to the pyrene-grafted peptide could induce a well-ordered 2D assembly by face-centered arene-perfluoroarene stacking. The DGEA-peptide 2D assembly with a flat structure, structural stability against enzymatic degradations, and a larger size can enhance the proliferation and differentiation of muscle cells via continuous interactions with cell membrane receptors integrin α2β1 showing a low intracellular uptake (15%) compared to that (62%) of the vesicular peptide assembly. These supramolecular approaches via the arene-perfluoroarene interaction provide a strategy to fabricate well-defined 2D peptide materials with an understanding of assembly at the molecular level for the next-generation peptide materials.

Self-healing cyclic peptide hydrogels

Hydrogels are soft materials of great interest in different areas such as chemistry, biology, and therapy. Gels made by the self-assembly of small molecules are known as supramolecular gels. The modulation of their properties by monomer molecular design is still difficult to predict due to the potential impact of subtle structural modifications in the self-assembly process. Herein, we introduce the design principles of a new family of self-assembling cyclic octapeptides of alternating chirality that can be used as scaffolds for the development of self-healing hydrogelator libraries with tunable properties. The strategy was used in the preparation of an amphiphilic cyclic peptide monomer bearing an alkoxyamine connector, which allowed the insertion of different aromatic aldehyde pendants to modulate the hydrophobic/hydrophilic balance and fine-tune the properties of the resulting gel. The resulting amphiphiles were able to form self-healable hydrogels with viscoelastic properties (loss tangent, storage modulus), which were strongly dependent on the nature and number of aromatic moieties anchored to the hydrophilic peptide. Structural studies by SEM, STEM and AFM indicated that the structure of the hydrogels was based on a dense network of peptide nanotubes. Excellent agreement was established between the peptide primary structure, nanotube length distributions and viscoelastic behaviour.

CO2 Induces Symmetry Breaking in Layered Dipeptide Crystals

Control of symmetry breaking of materials provides large opportunities to regulate their properties and functions. Herein, we report breaking the symmetry of layered dipeptide crystals by utilizing CO₂ to induce the adjacent monomolecular layers to stack from the opposite to the same direction. The role of CO₂ is to cover the interlayer interaction sites and force the dipeptides to adsorb at asymmetric positions. Further, the dipeptide crystals exhibit far superior piezoelectricity after symmetry breaking and the piezoelectric voltage generated from the dipeptide-based generators becomes more than 500 % higher than before. This work reveals a potential route to engineer structures and properties of layered materials and provides a deep insight into the control of non-covalent interactions.

Antimicrobial nano-assemblies of tryptocidine C, a tryptophan-rich cyclic decapeptide, from ethanolic solutions

Tryptocidine C (TpcC), a Trp-rich cyclodecapeptide is a minor constituent in the antibiotic tyrothricin complex from Brevibacillus parabrevis. TpcC possesses a high tendency to oligomerise in aqueous solutions and dried TpcC forms distinct self-assembled nanoparticles. High-resolution scanning electron microscopy revealed the influence of different ethanol:water solvent systems on TpcC self-assembly, with the TpcC, dried from a high concentration in 15% ethanol, primarily assembling into small nanospheres with 24.3 nm diameter and 0.05 polydispersity. TpcC at 16 μM, near its CMC, formed a variety of structures such as small nanospheres, large dense nanospheroids and facetted 3-D-crystals, as well as sheets and coarse carpet-like structures which depended on ethanol concentration. Drying 16 μM TpcC from 75% ethanol resulted in highly facetted 3-D crystals, as well as small nanospheres, while those in 10% ethanol preparation had less defined facets. Drying from 20 to 50% ethanol led to polymorphic architectures with a few defined nanospheroids and various small nanoparticles, imbedded in carpet- and sheet-like structures. These polymorphic surface morphologies correlated with maintenance of fluorescence properties and the surface-derived antibacterial activity against Staphylococcus aureus over time, while there was a significant change in fluorescence and loss in activity in the 10% and 75% preparations where 3-D crystals were observed. This indicated that TpcC oligomerisation in solutions with 20-50% ethanol leads to metastable structures with a high propensity for release of antimicrobial moieties, while those leading to crystallisation limit active moieties release. TpcC nano-assemblies can find application in antimicrobial coatings, surface disinfectants, food packaging and wound healing materials.

Morphological transition and transformation of 2D nanosheets by controlling the balance of ππ stacking interaction and crystalline driving forces

Nanoscale organic two-dimensional (2D) materials of block polymers (BCPs) have attracted interest on account of their wide potential applications in a range of fields. Herein, we design a new poly(p-phenylenevinylene) (PPV) based BCP that contains a triisopropylsilyl side chain and poly (2-vinyl pyridine) (P2VP) corona, which could assemble into a series of 2D square and rectangular micelles in isopropanol. The aspect ratios and the scales of the 2D micelles can be tuned in two ways, including altering the ratios of the P2VP and PPV-TIPS blocks and their concentrations. By precisely controlling the aspect ratios, micro-scale rod-like micelles are also obtained. From in depth studies of the morphology transition from rectangular micelles to rod-like or square micelles, it is found that the BCPs initially organize into fibers and then assemble into final micelles by the combined forces of π-π interactions and the crystalline force from TIPS side chains. Based on the balance of the two interactions, 2D circle-like micelles are also achieved by heterogenous co-assembly of two kinds of polymers with different cores.

Microfluidic-driven ultrafast self-assembly of a dipeptide into stimuli-responsive 0D, 1D, and 2D nanostructures and as hydrolase mimic

Numerous peptides have been utilized to explore the efficacy of their self-assembly to produce nanostructures to mimic the self-organization capability of biomolecules in nature. Self-assembled nanostructures have significant applicability for a range of diverse applications. While the ability to create self-assembled functional materials has greatly improved, the self-assembly process, which results in ordered 0D, 1D, and 2D nanostructures, is still time-consuming. Moreover, in situ structural transformation from one self-assembled structure to another with different dimensions presents an additional challenge. Therefore, in this report, we demonstrate self-assembly in an ultrafast fashion to access four different nanostructures, namely, twisted bundle (TB), nanoparticle (NP), nanofiber (NF), and nanosheet (NS), from a simple dipeptide with the aid of simple microfluidic reactors by applying different stimuli. Additionally, an integrated microfluidic system enabled rapid structural switchover between two types in an ultrashort period of time. It is interesting to note that the formation of the twisted bundle (TB) morphology enabled the formation of an extended entangled network, which resulted in the formation of a hydrogel (1 w/v%). In addition, the nanostructures obtained using the ultrafast self-assembly process were investigated to study their hydrolase enzyme activity mimicking performance against a model substrate (p-NPA) reaction. Intriguingly, we found that our nanostructures were suitably well ordered, and when taking molecular mass into consideration, showed improved catalytic efficiency as compared to the native enzymes.

Fluorescent Microswimmers Based on Cross-β Amyloid Nanotubes and Divergent Cascade Networks

Shaped through millions of years of evolution, the spatial localization of multiple enzymes in living cells employs extensive cascade reactions to enable highly coordinated multimodal functions. Herein, by utilizing a complex divergent cascade, we exploit the catalytic potential as well as templating abilities of streamlined cross-β amyloid nanotubes to yield two orthogonal roles simultaneously. The short peptide based paracrystalline nanotube surfaces demonstrated the generation of fluorescence signals within entangled networks loaded with alcohol dehydrogenase (ADH). The nanotubular morphologies were further used to generate cascade-driven microscopic motility through surface entrapment of sarcosine oxidase (SOX) and catalase (Cat). Moreover, a divergent cascade network was initiated by upstream catalysis of the substrate molecules through the surface mutation of catalytic moieties. Notably, the resultant downstream products led to the generation of motile fluorescent microswimmers by utilizing the two sets of orthogonal properties and, thus, mimicked the complex cascade-mediated functionalities of extant biology.

Bioinspired enzymatic compartments constructed by spatiotemporally confined in situ self-assembly of catalytic peptide

Enzymatic compartments, inspired by cell compartmentalization, which bring enzymes and substrates together in confined environments, are of particular interest in ensuring the enhanced catalytic efficiency and increased lifetime of encapsulated enzymes. Herein, we constructed bioinspired enzymatic compartments (TPE-Q18H@GPs) with semi-permeability by spatiotemporally controllable self-assembly of catalytic peptide TPE-Q18H in hollow porous glucan particles (GPs), allowing substrates and products to pass in/out freely, while enzymatic aggregations were retained. Due to the enrichment of substrates and synergistic effect of catalytic nanofibers formed in the confined environment, the enzymatic compartments exhibited stronger substrate binding affinity and over two-fold enhancement of second-order kinetic constant (k_cat/K_m) compared to TPE-Q18H nanofibers in disperse system. Moreover, GPs enabled the compartments sufficient stability against perturbation conditions, such as high temperature and degradation. This work opens an intriguing avenue to construct enzymatic compartments using porous biomass materials and has fundamental implications for constructing artificial organelles and even artificial cells.