Nanoarchitectonics of biomolecular assemblies for functional applications

Cooperative dissolution of peptidomimetic vesicles and amyloid β fibrils

The aggregation of amyloid proteins in the brain is a significant neurotoxic event that contributes to neurodegenerative disorders. The aggregation of amyloid beta (Aβ), particularly Aβ42 monomers, into various forms such as oligomers, protofibrils, fibrils, and amyloid plaques is a key pathological feature in Alzheimer's disease. As a result, Aβ42 is a primary target and the development of molecular strategies for the dissolution of Aβ42 aggregates is considered a promising approach to mitigating Alzheimer's disease pathology. A set of pyrene-conjugated peptidomimetics derived from Aβ14-23 (AkdcPy, AkdmPy, and AkdnPy) by incorporating an unnatural amino acid [kd: cyclo(Lys-Asp)] were studied for their ability to modulate Aβ42 aggregation. AkdcPy and AkdmPy formed vesicular structures in aqueous media. The vesicles of AkdmPy loaded with the neuroprotective compound berberine (Ber), dissipated mutually in the presence of preformed Aβ42 fibrils. During this process, the active drug Ber was released. This work is expected to inspire the development of drug-loaded peptidomimetic-based therapeutic formulations to modulate disorders associated with amyloid toxicity.

Peptide-Based Biomaterials for Bone and Cartilage Regeneration

The healing of osteochondral defects (OCDs) that result from injury, osteochondritis, or osteoarthritis and bear lesions in the cartilage and bone, pain, and loss of joint function in middle- and old-age individuals presents challenges to clinical practitioners because of non-regenerative cartilage and the limitations of current therapies. Bioactive peptide-based osteochondral (OC) tissue regeneration is becoming more popular because it does not have the immunogenicity, misfolding, or denaturation problems associated with original proteins. Periodically, reviews are published on the regeneration of bone and cartilage separately; however, none of them addressed the simultaneous healing of these tissues in the complicated heterogeneous environment of the osteochondral (OC) interface. As regulators of cell adhesion, proliferation, differentiation, angiogenesis, immunomodulation, and antibacterial activity, potential therapeutic strategies for OCDs utilizing bone and cartilage-specific peptides should be examined and investigated. The main goal of this review was to study how they contribute to the healing of OCDs, either alone or in conjunction with other peptides and biomaterials.

Distinguishing anti-PEG antibodies by specificity for the PEG terminus using nanoarchitectonics-based antibiofouling cello-oligosaccharide platforms

The conjugation of poly(ethylene glycol) (PEG) to therapeutic proteins or nanoparticles is a widely used pharmaceutical strategy to improve their therapeutic efficacy. However, conjugation can make PEG immunogenic and induce the production of anti-PEG antibodies, which decreases both the therapeutic efficacy after repeated dosing and clinical safety. To address these concerns, it is essential to analyze the binding characteristics of anti-PEG antibodies to PEG. However, distinguishing anti-PEG antibodies is still a difficult task. Herein, we demonstrate the use of antibiofouling cello-oligosaccharide assemblies tethering one-terminal methoxy oligo(ethylene glycol) (OEG) ligands for distinguishing anti-PEG antibodies in a simple manner. The OEG ligand-tethering two-dimensional crystalline cello-oligosaccharide assemblies were stably dispersed in a buffer solution and had antibiofouling properties against nonspecific protein adsorption. These characteristics allowed enzyme-linked immunosorbent assays (ELISAs) to be simply performed by cycles of centrifugation/redispersion of aqueous dispersions of the assemblies. The simple assays revealed that the specific OEG ligand-tethering assemblies could distinguish anti-PEG antibodies to detect a specific antibody that preferentially binds to the methoxy terminus of the PEG chain with 3 repeating ethylene glycol units. Furthermore, quantitative detection of the antibodies was successfully performed with high sensitivity even in the presence of serum. The detectable and quantifiable range of antibody concentrations covered those required clinically. Our findings open a new avenue for analyzing the binding characteristics of anti-PEG antibodies in biological samples.

Multipotential Role of Growth Factor Mimetic Peptides for Osteochondral Tissue Engineering

Articular cartilage is characterized by a poor self-healing capacity due to its aneural and avascular nature. Once injured, it undergoes a series of catabolic processes which lead to its progressive degeneration and the onset of a severe chronic disease called osteoarthritis (OA). In OA, important alterations of the morpho-functional organization occur in the cartilage extracellular matrix, involving all the nearby tissues, including the subchondral bone. Osteochondral engineering, based on a perfect combination of cells, biomaterials and biomolecules, is becoming increasingly successful for the regeneration of injured cartilage and underlying subchondral bone tissue. To this end, recently, several peptides have been explored as active molecules and enrichment motifs for the functionalization of biomaterials due to their ability to be easily chemically synthesized, as well as their tunable physico-chemical features, low immunogenicity issues and functional group modeling properties. In addition, they have shown a good aptitude to penetrate into the tissue due to their small size and stability at room temperature. In particular, growth-factor-derived peptides can play multiple functions in bone and cartilage repair, exhibiting chondrogenic/osteogenic differentiation properties. Among the most studied peptides, great attention has been paid to transforming growth factor-β and bone morphogenetic protein mimetic peptides, cell-penetrating peptides, cell-binding peptides, self-assembling peptides and extracellular matrix-derived peptides. Moreover, recently, phage display technology is emerging as a powerful selection technique for obtaining functional peptides on a large scale and at a low cost. In particular, these peptides have demonstrated advantages such as high biocompatibility; the ability to be immobilized directly on chondro- and osteoinductive nanomaterials; and improving the cell attachment, differentiation, development and regeneration of osteochondral tissue. In this context, the aim of the present review was to go through the recent literature underlining the importance of studying novel functional motifs related to growth factor mimetic peptides that could be a useful tool in osteochondral repair strategies. Moreover, the review summarizes the current knowledge of the use of phage display peptides in osteochondral tissue regeneration.

Biomimetic and Biological Nanoarchitectonics

A post-nanotechnology concept has been assigned to an emerging concept, nanoarchitectonics. Nanoarchitectonics aims to establish a discipline in which functional materials are fabricated from nano-scale components such as atoms, molecules, and nanomaterials using various techniques. Nanoarchitectonics opens ways to form a more unified paradigm by integrating nanotechnology with organic chemistry, supramolecular chemistry, material chemistry, microfabrication technology, and biotechnology. On the other hand, biological systems consist of rational organization of constituent molecules. Their structures have highly asymmetric and hierarchical features that allow for chained functional coordination, signal amplification, and vector-like energy and signal flow. The process of nanoarchitectonics is based on the premise of combining several different processes, which makes it easier to obtain a hierarchical structure. Therefore, nanoarchitectonics is a more suitable methodology for creating highly functional systems based on structural asymmetry and hierarchy like biosystems. The creation of functional materials by nanoarchitectonics is somewhat similar to the creation of functional systems in biological systems. It can be said that the goal of nanoarchitectonics is to create highly functional systems similar to those found in biological systems. This review article summarizes the synthesis of biomimetic and biological molecules and their functional structure formation from various viewpoints, from the molecular level to the cellular level. Several recent examples are arranged and categorized to illustrate such a trend with sections of (i) synthetic nanoarchitectonics for bio-related units, (ii) self-assembly nanoarchitectonics with bio-related units, (iii) nanoarchitectonics with nucleic acids, (iv) nanoarchitectonics with peptides, (v) nanoarchitectonics with proteins, and (vi) bio-related nanoarchitectonics in conjugation with materials.

Chiral assembly of organic luminogens with aggregation-induced emission

Chirality is important to chemistry, biology and optoelectronic materials. The study on chirality has lasted for more than 170 years since its discovery. Recently, chiral materials with aggregation-induced emission (AIE) have attracted increasing interest because of their fascinating photophysical properties. In this review, we discussed the recent development of chiral materials with AIE properties, including their molecular structures, self-assembly and functions. Generally, the most effective strategy to design a chiral AIE luminogen (AIEgen) is to attach a chiral scaffold to an AIE-active fluorophore through covalent bonds. Moreover, some propeller-like or shell-like AIEgens without chiral units exhibit latent chirality upon mirror image symmetry breaking. The chirality of achiral AIEgens can also be induced by some optically active molecules through non-covalent interactions. The introduction of an AIE unit into chiral materials can enhance the efficiency of their circularly polarized luminescence (CPL) in the solid state and the dissymmetric factors of their helical architectures formed through self-assembly. Thus, highly efficient circularly polarized organic light-emitting diodes (CPOLEDs) with AIE characteristics are developed and show great potential in 3D displays. Chiral AIEgens are also widely utilized as "turn on" sensors for rapid enantioselective determination of chiral reagents. It is anticipated that the present review can entice readers to realize the importance of chirality and attract much more chemists to contribute their efforts to chirality and AIE study.

Progress in Molecular Nanoarchitectonics and Materials Nanoarchitectonics

Although various synthetic methodologies including organic synthesis, polymer chemistry, and materials science are the main contributors to the production of functional materials, the importance of regulation of nanoscale structures for better performance has become clear with recent science and technology developments. Therefore, a new research paradigm to produce functional material systems from nanoscale units has to be created as an advancement of nanoscale science. This task is assigned to an emerging concept, nanoarchitectonics, which aims to produce functional materials and functional structures from nanoscale unit components. This can be done through combining nanotechnology with the other research fields such as organic chemistry, supramolecular chemistry, materials science, and bio-related science. In this review article, the basic-level of nanoarchitectonics is first presented with atom/molecular-level structure formations and conversions from molecular units to functional materials. Then, two typical application-oriented nanoarchitectonics efforts in energy-oriented applications and bio-related applications are discussed. Finally, future directions of the molecular and materials nanoarchitectonics concepts for advancement of functional nanomaterials are briefly discussed.

Molecular Architectonics-guided Design of Biomaterials

The quest for mastering the controlled engineering of dynamic molecular assemblies is the basis of molecular architectonics. The rational use of noncovalent interactions to programme the molecular assemblies allow the construction of diverse molecular and material architectures with novel functional properties and applications. Understanding and controlling the assembly of molecular systems are daunting tasks owing to the complex factors that govern at the molecular level. Molecular architectures depend on the design of functional molecular modules through the judicious selection of functional core and auxiliary units to guide the precise molecular assembly and co-assembly patterns. Biomolecules with built-in information for molecular recognition are the ultimate examples of evolutionary guided molecular recognition systems that define the structure and functions of living organisms. Explicit use of biomolecules as auxiliary units to command the molecular assemblies of functional molecules is an intriguing exercise in the scheme of molecular architectonics. In this minireview, we discuss the implementation of the principles of molecular architectonics for the development of novel biomaterials with functional properties and applications ranging from sensing, drug delivery to neurogeneration and tissue engineering. We present the molecular designs pioneered by our group owing to the requirement and scope of the article while acknowledging the designs pursued by several research groups that befit the concept.

Threading Intercalator-Induced Nanocondensates and Role of Endogenous Metal Ions in Decondensation for DNA Delivery

The interplay of condensation and decondensation of DNA plays a crucial role in chromosome maintenance and gene expression. The molecular architectonics governing the chromatin condensation-decondensation cycle are worth studying, as DNA performs unique and distinct roles in each state and switches between two states without the loss of structural and functional integrity. This phenomenon has been adapted and implemented in transfection studies. Effective gene delivery into the cells to achieve respectable transfection efficiency has remained a challenge and emphasizes the need for understanding the steps involved in DNA delivery and transfection. Especially, recognizing the factors that effectively regulate DNA decondensation can provide logical solutions to the hurdles affecting the transfection efficiency. We designed a set of small molecule-based threading intercalation ligands as model condensing agents to study various factors influencing the DNA condensation and decondensation process. This study revealed condensation of DNA into nanocondensate by the threading intercalator and endogenous stimuli induced effective decondensation. Further, DNA nanocondensates are tracked using the intrinsic fluorescence in the lower pH of endocytic pathway and were evaluated as nonviral vectors for in cellulo delivery of plasmids. The correlation of decondensation of DNA nanocondensate with endogenous metal ions at their physiological concentrations provided valuable insights and implications for intracellular DNA delivery.

Hybrid Hydrogel Electrolyte Based on Metal-Organic Supermolecular Self-Assembly and Polymer Chemical Cross-Linking for Rechargeable Aqueous Zn-MnO2 Batteries

Multifunctional metal-organic supramolecular hydrogels have achieved great progress nowadays. However, their applications in aqueous batteries for flexible energy storage devices remain limited due to their unsatisfactory mechanical properties. Here, we report a rapid formation of supramolecular hydrogel by adenosine 5'-monophosphate (AMP) and manganese ions (Mn²⁺). Additionally, the AMP-Mn hydrogel is combined with chemical cross-linking poly(vinyl alcohol) (PVA) polymer networks to form an AMP-Mn/PVA hybrid hydrogel, which effectively solves the problems with regard to the mechanical properties and stability of metal-organic supramolecular hydrogels as well as self-healing of tough chemical cross-linking polymer networks. The AMP-Mn/PVA hybrid hydrogel served as the hydrogel electrolyte to fabricate flexible Zn-MnO₂ batteries, which exhibit fast ion conductivity, excellent electrochemical stability, and robust mechanical strength, indicating feasible practical application prospects. This investigation provides a promising opportunity for the application of metal-organic supramolecular hydrogels in the field of energy storage.

Intrinsic Role of Molecular Architectonics in Enhancing the Catalytic Activity of Lead in Glucose Hydrolysis

Lewis acidity plays a key role in the catalytic activity of lead ion (Pb^II) in the hydrolysis of glucose in solution under harsh synthetic conditions. We report a number of structurally similar d-gluconamide amphiphiles as functional organic ligands with active an -NH center capable of coordinating Pb^II (viz., Pb^II-N-C) in basic condition to enhance the catalytic efficiency through the scheme of molecular architectonics. Amphiphiles with different hydrophobic unit form assembly-architectures with a varying second coordination sphere around the active metal ion center. As a result, the active Pb^II center in each architecture exhibits substantially different efficiency toward catalyzing the glucose hydrolysis under ambient temperature. The catalytic performance of the dynamic and reversible gluconamide-Pb^II assembly-architectures are highly dependent on their chemical environments in solution. Further, the active Pb^II center of gluconamide-Pb^II complex in the assembly architecture and dispersed states exhibits distinct outcomes with the former being a superior catalyst than the latter as well as Pb^II alone. The current study demonstrates the potential of molecular architectonics that relies on the hydrophobic units of designer functional amphiphiles to enrich surface electron density with enhanced σ-donation ability through space which substantially improves the catalytic efficiency of Pb^II toward glucose hydrolysis at ambient temperature.

Molecular architectonics of DNA for functional nanoarchitectures

DNA is the key biomolecule central to almost all processes in living organisms. The eccentric idea of utilizing DNA as a material building block in molecular and structural engineering led to the creation of numerous molecular-assembly systems and materials at the nanoscale. The molecular structure of DNA is believed to have evolved over billions of years, with structure and stability optimizations that allow life forms to sustain through the storage and transmission of genetic information with fidelity. The nanoscale structural characteristics of DNA (2 nm thickness and ca. 40-50 nm persistence length) have inspired the creation of numerous functional patterns and architectures through noncovalent conventional and unconventional base pairings as well as through mutual templating-interactions with small organic molecules and metal ions. The recent advancements in structural DNA nanotechnology allowed researchers to design new DNA-based functional materials with chemical and biological properties distinct from their parent components. The modulation of structural and functional properties of hybrid DNA ensembles of small functional molecules (SFMs) and short oligonucleotides by adapting the principles of molecular architectonics enabled the creation of novel DNA nanoarchitectures with potential applications, which has been termed as templated DNA nanotechnology or functional DNA nanoarchitectonics. This review highlights the molecular architectonics-guided design principles and applications of the derived DNA nanoarchitectures. The advantages and ability of functional DNA nanoarchitectonics to overcome the trivial drawbacks of classical DNA nanotechnology to fulfill realistic and practical applications are highlighted, and an outlook on future developments is presented.

Pteridine derivatives: novel low-molecular-weight organogelators and their piezofluorochromism

Here, π-conjugated compounds based on pteridine derivatives were synthesized and their self-assembling behaviors in a variety of organic solvents and piezofluorochromism were studied.

Synthetic Biology for Multiscale Designed Biomimetic Assemblies: From Designed Self-Assembling Biopolymers to Bacterial Bioprinting

Nature is based on complex self-assembling systems that span from the nanoscale to the macroscale. We have already begun to design biomimetic systems with properties that have not evolved in nature, based on designed molecular interactions and regulation of biological systems. Synthetic biology is based on the principle of modularity, repurposing diverse building modules to design new types of molecular and cellular assemblies. While we are currently able to use techniques from synthetic biology to design self-assembling molecules and re-engineer functional cells, we still need to use guided assembly to construct biological assemblies at the macroscale. We review the recent strategies for designing biological systems ranging from molecular assemblies based on self-assembly of (poly)peptides to the guided assembly of patterned bacteria, spanning 7 orders of magnitude.

Self-assembly as a key player for materials nanoarchitectonics

The development of science and technology of advanced materials using nanoscale units can be conducted by a novel concept involving combination of nanotechnology methodology with various research disciplines, especially supramolecular chemistry. The novel concept is called 'nanoarchitectonics' where self-assembly processes are crucial in many cases involving a wide range of component materials. This review of self-assembly processes re-examines recent progress in materials nanoarchitectonics. It is composed of three main sections: (1) the first short section describes typical examples of self-assembly research to outline the matters discussed in this review; (2) the second section summarizes self-assemblies at interfaces from general viewpoints; and (3) the final section is focused on self-assembly processes at interfaces. The examples presented demonstrate the strikingly wide range of possibilities and future potential of self-assembly processes and their important contribution to materials nanoarchitectonics. The research examples described in this review cover variously structured objects including molecular machines, molecular receptors, molecular pliers, molecular rotors, nanoparticles, nanosheets, nanotubes, nanowires, nanoflakes, nanocubes, nanodisks, nanoring, block copolymers, hyperbranched polymers, supramolecular polymers, supramolecular gels, liquid crystals, Langmuir monolayers, Langmuir-Blodgett films, self-assembled monolayers, thin films, layer-by-layer structures, breath figure motif structures, two-dimensional molecular patterns, fullerene crystals, metal-organic frameworks, coordination polymers, coordination capsules, porous carbon spheres, mesoporous materials, polynuclear catalysts, DNA origamis, transmembrane channels, peptide conjugates, and vesicles, as well as functional materials for sensing, surface-enhanced Raman spectroscopy, photovoltaics, charge transport, excitation energy transfer, light-harvesting, photocatalysts, field effect transistors, logic gates, organic semiconductors, thin-film-based devices, drug delivery, cell culture, supramolecular differentiation, molecular recognition, molecular tuning, and hand-operating (hand-operated) nanotechnology.

Synthesis, Optoelectronic Properties, Self-Association, and Base Pairing of Nucleobase-Functionalized Oligothiophenes

Device-relevant π-conjugated oligothiophenes with the canonical nucleobases directly embedded into the π-framework have been designed, synthesized, and characterized. These oligomers offer the ability to tune optoelectronic properties via the intimate merging of the nucleobase molecular electronic structure with base-pairing fidelity. Analysis of their optical and electronic properties in a hydrogen-bond-disrupting solvent (DMF) indicates that the nucleobase identity influences the intrinsic electronic properties of the semiconductors. These differences are supported by DFT calculations which demonstrate that the HOMO/LUMO orbitals are distributed differently for each compound. The solubility and competition between self-association and base pairing in a hydrogen-bond-supporting solvent (chloroform) was studied to better understand the oligomer behavior under conditions relevant for downstream solution processing into thin-film devices. These solution studies reveal that in each case base-pairing is preferred to self-aggregation; the relatively weak heteroassociation of 1A-1U (35 ± 5 M^-1) should be amenable to facile solution processing and successive hydrogen bond formation in the solid state, while the strong heteroassociation between 1G and 1C (>10⁴ M^-1) should enable assemblies to be preformed in solution. These results are expected to enable the synthesis of more complex π-conjugated architectures and facilitate their extension to optoelectronic devices.

Architectonics: Design of Molecular Architecture for Functional Applications

The term architectonics has its roots in the architectural and philosophical (as early as 1600s) literature that refers to "the theory of structure" and "the structure of theory", respectively. The concept of architectonics has been adapted to advance the field of molecular self-assembly and termed as molecular architectonics. In essence, the methodology of organizing molecular units in the required and controlled configurations to develop advanced functional systems for materials and biological applications comprises the field of molecular architectonics. This concept of designing noncovalent systems enables to focus on different functional aspects of designer molecules for biological and nonbiological applications and also strengthens our efforts toward the mastery over the art of controlled molecular self-assemblies. Programming complex molecular interactions and assemblies for specific functions has been one of the most challenging tasks in the modern era. Meticulously ordered molecular assemblies can impart remarkable developments in several areas spanning energy, health, and environment. For example, the well-defined nano-, micro-, and macroarchitectures of functional molecules with specific molecular ordering possess potential applications in flexible electronics, photovoltaics, photonic crystals, microreactors, sensors, drug delivery, biomedicine, and superhydrophobic coatings, among others. The functional molecular architectures having unparalleled properties are widely evident in various designs of Nature. By drawing inspirations from Nature, intended molecular architectures can be designed and developed to harvest various functions, as there is an inexhaustible resource and scope. In this Account, we present exquisite designer molecules developed by our group and others with an objective to master the art of molecular recognition and self-assembly for functional applications. We demonstrate the tailor-ability of molecular self-assemblies by employing biomolecules like amino acids and nucleobases as auxiliaries. Naphthalenediimide (NDI), perylenediimide (PDI), and few other molecular systems serve as functional modules. The effects of stereochemistry and minute structural modifications in the molecular designs on the supramolecular interactions, and construction of self-assembled zero-dimensional (OD), one-dimensional (1D), and two-dimensional (2D) nano- and microarchitectures like particles, spheres, cups, bowls, fibers, belts, helical belts, supercoiled helices, sheets, fractals, and honeycomb-like arrays are discussed in extensive detail. Additionally, we present molecular systems that showcase the elegant designs of coassembly, templated assembly, hierarchical assembly, transient self-assembly, chiral denaturation, retentive helical memory, self-replication, supramolecular regulation, supramolecular speciation, supernon linearity, dynamic pathway complexity, supramolecular heterojunction, living supramolecular polymerization, and molecular machines. Finally, we describe the molecular engineering principles learnt over the years that have led to several applications, namely, organic electronics, self-cleaning, high-mechanical strength, and tissue engineering.

Nucleobases, nucleosides, and nucleotides: versatile biomolecules for generating functional nanomaterials

The incorporation of biomolecules into nanomaterials generates functional nanosystems with novel and advanced properties, presenting great potential for applications in various fields. Nucleobases, nucleosides and nucleotides, as building blocks of nucleic acids and biological coenzymes, constitute necessary components of the foundation of life. In recent years, as versatile biomolecules for the construction or regulation of functional nanomaterials, they have stimulated interest in researchers, due to their unique properties such as structural diversity, multiplex binding sites, self-assembly ability, stability, biocompatibility, and chirality. In this review, strategies for the synthesis of nanomaterials and the regulation of their morphologies and functions using nucleobases, nucleosides, and nucleotides as building blocks, templates or modulators are summarized alongside selected applications. The diverse applications range from sensing, bioimaging, and drug delivery to mimicking light-harvesting antenna, the construction of logic gates, and beyond. Furthermore, some perspectives and challenges in this emerging field are proposed. This review is directed toward the broader scientific community interested in biomolecule-based functional nanomaterials.

Nanoarchitectonics from Molecular Units to Living-Creature-Like Motifs

Important points for the fabrication of functional materials are the creation of nanoscale/molecular-scale units and architecting them into functional materials and systems. Recently, a new conceptual paradigm, nanoarchitectonics, has been proposed to combine nanotechnology and other methodologies including supramolecular chemistry, self-assembly and self-organization to satisfy major features of nanoscience and promote the creation of functional materials and systems. In this account article, our recent research results in materials development based on the nanoarchitectonics concept are summarized in two stories, (i) nanoarchitectonics from fullerenes as the simplest nano-units and (ii) dimension-dependent nanoarchitectonics from various structural units. The former demonstrates creativity of the nanoarchitectonics concept only with simple construction stuffs on materials fabrications, and a wide range of material applicability for the nanoarchitectonics strategy is realized in the latter ones.

Hydrogels Based on Ag+ -Modulated Assembly of 5'-Adenosine Monophosphate for Enriching Biomolecules

Supramolecular hydrogels obtained by combining 5'-adenosine monophosphate (AMP) with Ag⁺ were fabricated in this work. Their gelation capability was enhanced by increasing the concentration of Ag⁺ or decreasing the pH. The gels are very sensitive to light, which endows them with potential applications as visible-light photosensitive materials. Coordination between the nucleobase of AMP and Ag⁺ , as well as π-π stacking of nucleobases, are considered to be the main driving forces for self-assembly. The hydrogels successfully achieved the encapsulation and enrichment of biomolecules. Hydrogen bonding between the amino group of guest molecules and silver nanoparticles along the nanofibers drives the enrichment and is considered to be a crucial interaction.

Molecular Self-Assembly of Cyclic Dipeptide Derivatives and Their Applications

Cyclic dipeptides (CDPs) are heterocyclic 2,5-diketopiperazines with exceptional structural rigidity, enzymatic stability, and biological activity, exhibiting a substantial tendency to take part in intermolecular interactions. Strong intermolecular interactions driven by unique hydrogen bonding patterns render CDPs with a high propensity to undergo molecular self-assembly. In this Review, the aim is to provide a comprehensive summary of design strategies used to engineer the molecular self-assembly of CDPs into functional nano- and micro-architectures and molecular gels with potential applications in biomedical and materials engineering fields.

Emergent Behaviors in Kinetically Controlled Dynamic Self-Assembly of Synthetic Molecular Systems

Living systems are categorically a kinetic state of matter that exhibits complex functions and emergent behaviors. By contrast, synthetic systems are relatively simple and are typically controlled by the thermodynamic parameters. To understand this inherent difference between the biological and synthetic systems, novel approaches are of vital importance. In this regard, we have designed a three-component molecular system (a triad) by conjugating an amino acid with two functional molecules (naphthalenediimide and pyrene), which facilitates kinetically controlled self-assemblies. Herein, we describe three different molecular aggregation states of triads (entitled State I, State II, and State III) and also the dynamic pathway complexities associated with their transformations from one state to another. By meticulously employing the triads of different molecular aggregation states and the stereochemical information of the amino acid, we report emergent behaviors termed "supramolecular speciation" and "supramolecular regulation". Further, we present a hitherto unknown emergent property in a self-assembled state under the majority-rules experiment, which has been termed "super-nonlinearity". This work provides novel insights into complex synthetic systems having unprecedented functions and properties. Such emergent behaviors of synthetic triads that involve an interplay among complex interactions may find relevance in the context of prebiotic chemical evolution.

Molecular Architectonics of Naphthalenediimides for Efficient Structure-Property Correlation

We present a bioinspired design strategy to effectively tailor the assembly of naphthalenediimides (NDIs) into a wide variety of architectures by functionalizing with amino acid derivatives. This bioinspired process of custom designing and engineering molecular assemblies is termed "bioinspired architectonics". By employing minute structural mutations in the form of α-substituents of amino acids, we successfully engineered molecular assembly of NDIs into zero-dimensional (0D, spheres), one-dimensional (1D, fibers), and two-dimensional (2D, sheets) architectures. The 2D sheets of phenylalanine methylester appended NDI 1 showed remarkable bulk electron mobility of up to 1 cm(2) V(-1)s(-1). With the aid of photophysical, diffraction, and microscopy techniques we rationalize the effect of molecular structure with their ordering and electronic properties in an effort to find structure-property correlations via a bioinspired modular approach.

Combinatorial Approach to Nanoarchitectonics for Nonviral Delivery of Nucleic Acids

Nanoparticles based on cationic polymers, lipids or lipidoids are of great interest in the field of gene delivery applications. The research on these nanosystems is rapidly growing as they hold promise to treat wide variety of human diseases ranging from viral infections to genetic disorders and cancer. Recently, combinatorial design principles have been adopted for rapid generation of large numbers of chemically diverse polymers and lipids capable of forming multifunctional nanocarriers for the use in gene delivery applications. At the same time, current high-throughput screening systems as well as convenient cell assays and readout techniques allow for fast evaluation of cell transfection efficiencies and toxicities of libraries of novel gene delivery agents. This allows for a rapid evaluation of structure-function relationship as well as identification of novel efficient nanocarriers for cell transfection and gene therapy. Here, the recent contribution of high-throughput synthesis to the development of novel nanocarriers for gene delivery applications is described.

Nanoarchitectonics for Dynamic Functional Materials from Atomic-/Molecular-Level Manipulation to Macroscopic Action

Objects in all dimensions are subject to translational dynamism and dynamic mutual interactions, and the ability to exert control over these events is one of the keys to the synthesis of functional materials. For the development of materials with truly dynamic functionalities, a paradigm shift from "nanotechnology" to "nanoarchitectonics" is proposed, with the aim of design and preparation of functional materials through dynamic harmonization of atomic-/molecular-level manipulation and control, chemical nanofabrication, self-organization, and field-controlled organization. Here, various examples of dynamic functional materials are presented from the atom/molecular-level to macroscopic dimensions. These systems, including atomic switches, molecular machines, molecular shuttles, motional crystals, metal-organic frameworks, layered assemblies, gels, supramolecular assemblies of biomaterials, DNA origami, hollow silica capsules, and mesoporous materials, are described according to their various dynamic functions, which include short-term plasticity, long-term potentiation, molecular manipulation, switchable catalysis, self-healing properties, supramolecular chirality, morphological control, drug storage and release, light-harvesting, mechanochemical transduction, molecular tuning molecular recognition, hand-operated nanotechnology.

The Way to Nanoarchitectonics and the Way of Nanoarchitectonics

The critical differences between microtechnology and nanotechnology are discussed, and the necessity of a new paradigm, nanoarchitectonics, is proposed for the future development of nanotechnology. An important task in material fabrication is to harmonize various factors and effects, and to combine them into functional nanomaterials and nanosystems. It is the way of architectonics rather than that of an individual technology. Therefore, a novel terminology, nanoarchitectonics (nano + architecto +nics) has been proposed as a new paradigm of materials science and technology on the nanoscale. The statement by Feynman that "there's plenty of room at the bottom" is really true. With nanoarchitectonics in our hands, we can re-open the door to Feynman's huge room.

Nanoarchitectonics for carbon-material-based sensors

Recently, the nanoarchitectonics concept has been proposed to fabricate functional materials on the basis of concerted harmonization actions to control materials organization.

Organogelation of cyanovinylcarbazole with terminal benzimidazole: AIE and response for gaseous acid

The intense emission of carbazole-modified benzimidazole in xerogel-based film can be quenched rapidly by gaseous acid due to protonation.

Two-Dimensional Peptide and Protein Assemblies

Two-dimensional nanoscale assemblies (nanosheets) represent a promising structural platform to arrange molecular and supramolecular substrates with precision for integration into devices. This nanoarchitectonic approach has gained significant traction over the last decade, as a general concept to guide the fabrication of functional nanoscale devices. Sequence-specific biomolecules, e.g., peptides and proteins, may be considered excellent substrates for the fabrication of two-dimensional nanoarchitectonics. Molecular level instructions can be encoded within the sequence of monomers, which allows for control over supramolecular structure if suitable design principles could be elaborated. Due to the complexity of interactions between protomers, the development of principles aimed toward rational design of peptide and protein nanosheets is at a nascent stage. This review discusses the known two-dimensional peptide and protein assemblies to further our understanding of how to control the arrangement of molecules in two-dimensions.

Bioinspired Reductionistic Peptide Engineering for Exceptional Mechanical Properties

A simple solution-processing and self-assembly approach that exploits the synergistic interactions between multiple hydrogen bonded networks and aromatic interactions was utilized to synthesize molecular crystals of cyclic dipeptides (CDPs), whose molecular weights (~0.2 kDa) are nearly three orders of magnitude smaller than that of natural structural proteins (50–300 kDa). Mechanical properties of these materials, measured using the nanoindentation technique, indicate that the stiffness and strength are comparable and sometimes better than those of natural fibres. The measured mechanical responses were rationalized by recourse to the crystallographic structural analysis and intermolecular interactions in the self-assembled single crystals. With this work we highlight the significance of developing small molecule based bioinspired design strategies to emulate biomechanical properties. A particular advantage of the successfully demonstrated reductionistic strategy of the present work is its amenability for realistic industrial scale manufacturing of designer biomaterials with desired mechanical properties.

Qualitative/chiral sensing of amino acids by naked-eye fluorescence change based on morphological transformation and hierarchizing in supramolecular assemblies of pyrene-conjugated glycolipids

Supramolecular assemblies of fluorescent glycolipids exhibited molecular packing rearrangement as well as morphological transformation, in response to amino acid analytes. Naked-eye detectable fluorescence color changes and hydrogel formation as the result of the amplification of the molecular- and nanometer-scaled changes enabled not only qualitative analysis but also chiral sensing of a specific amino acid among 20 amino acids.

Crystallographic insight-guided nanoarchitectonics and conductivity modulation of an n-type organic semiconductor through peptide conjugation

Crystallographic insight-guided and bio-inspired molecular nanoarchitectonics of an n-type organic semiconductor is described to understand the structure–property correlation, for modulation of functional properties.