Review of NIR-responsive ''Smart'' carriers for photothermal chemotherapy

This review focuses on the versatile applications of near-infrared (NIR)-responsive smart carriers in biomedical applications, particularly drug delivery and photothermal chemotherapy. These carriers demonstrate multi-responsive theranostics capabilities, including pH-dependent drug release, targeted delivery of chemotherapeutics, heat-mediated drug release, and photothermal tumor damage. Biological samples are transparent to NIR light with a suitable wavelength, and therefore, NIR light is advantageous for deep-tissue penetration. It also generates sufficient heat in tissue samples, which is beneficial for on-demand NIR-responsive drug delivery in vivo systems. The development of biocompatible materials with sufficient NIR light absorption properties and drug-carrying functionality has shown tremendous growth in the last five years. Thus, this review offers insights into the current research development of NIR-responsive materials with therapeutic potential and prospects aimed at overcoming challenges to improve the therapeutic efficacy and safety in the dynamic field of NIR-responsive drug delivery.

Supramolecular Nanoarchitectonics Based on Antagonist Peptide Self-Assembly for Treatment of Liver Fibrosis

Therapeutic peptides have attracted increasing attention as anti-fibrotic drug candidates. However, the rapid degradation and insufficient liver accumulation of therapeutic peptides have seriously hampered their clinical translation. Here, the use of supramolecular nanoarchitectonics is reported to fabricate nanodrugs from therapeutic peptides for treating liver fibrosis. Self-assembling antagonist peptides are rationally designed and manipulated into uniform peptide nanoparticles with well-defined nanostructures and uniform sizes. Significantly, the peptide nanoparticles show enhanced accumulation in liver sites and limited distribution in other tissues. In vivo results show that the peptide nanoparticles exhibit greatly enhanced anti-fibrotic activity compared to the pristine antagonist along with good biocompatibility. These results indicate that self-assembly is a promising nanoarchitectonics approach to enhance the anti-fibrotic activity of therapeutic peptides for treating liver fibrosis.

Peptide hydrogels: Synthesis, properties, and applications in food science

Due to the unique and excellent biological, physical, and chemical properties of peptide hydrogels, their application in the biomedical field is extremely wide. The applications of peptide hydrogels are closely related to their unique responsiveness and excellent properties. However, its defects in mechanical properties, stability, and toxicity limit its application in the food field. In this review, we focus on the fabrication methods of peptide hydrogels through the physical, chemical, and biological stimulations. In addition, the functional design of peptide hydrogels by the incorporation with materials is discussed. Meanwhile, the excellent properties of peptide hydrogels such as the stimulus responsiveness, biocompatibility, antimicrobial properties, rheology, and stability are reviewed. Finally, the application of peptide hydrogel in the food field is summarized and prospected.

Nanoarchitectonics beyond perfect order - not quite perfect but quite useful

Nanoarchitectonics, like architectonics, allows the design and building of structures, but at the nanoscale. Unlike those in architectonics, and even macro-, micro-, and atomic-scale architectonics, the assembled structures at the nanoscale do not always follow the projected design. In fact, they do follow the projected design but only for self-assembly processes producing structures with perfect order. Here, we look at nanoarchitectonics allowing the building of nanostructures without a perfect arrangement of building blocks. Here, fabrication of structures from molecules, polymers, nanoparticles, and nanosheets to polymer brushes, layer-by-layer assembly structures, and hydrogels through self-assembly processes is discussed, where perfect order is not necessarily the aim to be achieved. Both planar substrate and spherical template-based assemblies are discussed, showing the challenging nature of research in this field and the usefulness of such structures for numerous applications, which are also discussed here.

Hierarchical Quatsome-RGD Nanoarchitectonic Surfaces for Enhanced Integrin-Mediated Cell Adhesion

The synthesis and study of the tripeptide Arg-Gly-Asp (RGD), the binding site of different extracellular matrix proteins, e.g., fibronectin and vitronectin, has allowed the production of a wide range of cell adhesive surfaces. Although the surface density and spacing of the RGD peptide at the nanoscale have already shown a significant influence on cell adhesion, the impact of its hierarchical nanostructure is still rather unexplored. Accordingly, a versatile colloidal system named quatsomes, based on fluid nanovesicles formed by the self-assembling of cholesterol and surfactant molecules, has been devised as a novel template to achieve hierarchical nanostructures of the RGD peptide. To this end, RGD was anchored on the vesicle's fluid membrane of quatsomes, and the RGD-functionalized nanovesicles were covalently anchored to planar gold surfaces, forming a state of quasi-suspension, through a long poly(ethylene glycol) (PEG) chain with a thiol termination. An underlying self-assembled monolayer (SAM) of a shorter PEG was introduced for vesicle stabilization and to avoid unspecific cell adhesion. In comparison with substrates featuring a homogeneous distribution of RGD peptides, the resulting hierarchical nanoarchitectonic dramatically enhanced cell adhesion, despite lower overall RGD molecules on the surface. The new versatile platform was thoroughly characterized using a multitechnique approach, proving its enhanced performance. These findings open new methods for the hierarchical immobilization of biomolecules on surfaces using quatsomes as a robust and novel tissue engineering strategy.

Construction of Zn-heptapeptide bionanozymes with intrinsic hydrolase-like activity for degradation of di(2-ethylhexyl) phthalate

Nanozyme with intrinsic enzyme-like activity has emerged as favorite artificial catalyst during recent years. However, current nanozymes are mainly limited to inorganic-derived nanomaterials, while biomolecule-sourced nanozyme (bionanozyme) are rarely reported. Herein, inspired by the basic structure of natural hydrolase family, we constructed 3 oligopeptide-based bionanozymes with intrinsic hydrolase-like activity by implementing zinc induced self-assembly of histidine-rich heptapeptides. Under mild condition, divalent zinc (Zn²⁺) impelled the spontaneous assembly of short peptides (i.e. Ac-IHIHIQI-CONH₂, Ac-IHIHIYI-CONH₂, and Ac-IHVHLQI-CONH₂), forming hydrolase-mimicking bionanozymes with β-sheet secondary conformation and nanofibrous architecture. As expected, the resultant bionanozymes were able to hydrolyze a serious of p-nitrophenyl esters, including not only the simple substrate with short side-chain (p-NPA), but also more complicated ones (p-NPB, p-NPH, p-NPO, and p-NPS). Moreover, the self-assembled Zn-heptapeptide bionanozymes were also proven to be capable of degrading di(2-ethylhexyl) phthalate (DEHP), a typical plasticizer, showing great potential for environmental remediation. Based on this study, we aim to provide theoretical references and exemplify a specific case for directing the construction and application of bionanozyme.

Synthesis, Self-Assembly, and Cell Responses of Aromatic IKVAV Peptide Amphiphiles

Synthetic bioactive aromatic peptide amphiphiles have been recognized as key elements of emerging biomedical strategies due to their biocompatibility, design flexibility, and functionality. Inspired by natural proteins, we synthesized two supramolecular materials of phenyl-capped Ile-Lys-Val-Ala-Val (Ben-IKVAV) and perfluorophenyl-capped Ile-Lys-Val-Ala-Val (PFB-IKVAV). We employed UV-vis absorption, fluorescence, circular dichroism, and Fourier-transform infrared spectroscopy to examine the driving force in the self-assembly of the newly discovered materials. It was found that both compounds exhibited ordered π-π interactions and secondary structures, especially PFB-IKVAV. The cytotoxicity of human mesenchymal stem cells (hMSCs) and cell differentiation studies was also performed. In addition, the immunofluorescent staining for neuronal-specific markers of MAP2 was 4.6 times (neural induction medium in the presence of PFB-IKVAV) that of the neural induction medium (control) on day 7. From analyzing the expression of neuronal-specific markers in hMSCs, it can be concluded that PFB-IKVAV may be a potential supramolecular biomaterial for biomedical applications.

Peptide-based supramolecular assembly drugs toward cancer theranostics

INTRODUCTION

: Peptide-based supramolecular self-assembly has been demonstrated to be a flexible approach for the fabrication of programmable de novo nanodrugs by employing synergistic or reciprocal intermolecular non-covalent interactions; this class of nanomaterials holds significant promise for clinical translation, especially as cancer theranostics.

AREAS COVERED

: In this review, we describe the concept of cancer theranostic drug assembly by employing non-covalent interactions. That is, molecular drugs are formulated into nanoscale and even microscale architectures by peptide-modulated self-assembly. A series of peptide-based supramolecular assembly drugs are discussed, with an emphasis on the relation between structural feature and theranostic performance.

EXPERT OPINION

: Molecular design, manipulation of non-covalent interactions and elucidation of structure-function relationships not only facilitate the implementation of supramolecular self-assembly principles in drug development, but also provide a new means for advancing anticancer nanostructured drugs toward clinical application.

Self-assembled dehydropeptide nanocarrier as a delivery system for antitumor drug temozolomide

Stable molecular conformation and intermolecular forces are essential for peptide self-assembly. In this study, one novel dehydropeptide (DDP) monomer (Boc-(Z)C^α,β-ΔPhe-Gly-NHMe, DDP 1) was prepared; its conformation was confirmed to be more stable than the normal peptide 2 by nuclear magnetic resonance (NMR) and X-ray crystal diffraction experiments. DDP 1 was self-assembled to one novel dehydropeptide nanomaterial (DDPN 1). Fourier transform infrared (FTIR) spectroscopy results showed that hydrogen bonding was the main driving force of self-assembly. Electron microscope images displayed that the DDPN 1 fibers were longer and more stable than peptide 2 nanomaterials. Results of cell activity and enzyme hydrolysis proved that DDPN 1 had excellent biocompatibility and resistance to the enzymatic hydrolysis of protease K. Therefore, the DDPN 1 was used to load the antitumor drug temozolomide (TMZ). Due to intermolecular hydrogen bonds formed between TMZ and DDPN 1, TMZ-loaded DDPN 1 had a high percent entrapment efficiency (EE) of 83.72 ± 4.30% (n = 8) and a percent drug loading efficiency (LE) of 6.70 ± 0.34% (n = 8), and the half-life of TMZ-loaded DDPN 1 was 2.5-3 times longer than that of TMZ at pH 7. The in vitro cell viability results revealed that TMZ-loaded DDPN 1 exhibited higher antitumor activity (IC₅₀ = 552.1 μM) against U118-MG than that of TMZ (IC₅₀ = 1980.1 μM), possibly because that U118-MG cells uptook more TMZ from TMZ-loaded DDPN 1 than from free TMZ directly. This study is expected to inspire the design of biocompatible nanocarriers applied for anti-enzymatic hydrolysis in drug delivery systems.

The Past and the Future of Langmuir and Langmuir-Blodgett Films

The Langmuir-Blodgett (LB) technique, through which monolayers are transferred from the air/water interface onto a solid substrate, was the first method to allow for the controlled assembly of organic molecules. With its almost 100 year history, it has been the inspiration for most methods to functionalize surfaces and produce nanocoatings, in addition to serving to explore concepts in molecular electronics and nanoarchitectonics. This paper provides an overview of the history of Langmuir monolayers and LB films, including the potential use in devices and a discussion on why LB films are seldom considered for practical applications today. Emphasis is then given to two areas where these films offer unique opportunities, namely, in mimicking cell membrane models and exploiting nanoarchitectonics concepts to produce sensors, investigate molecular recognitions, and assemble molecular machines. The most promising topics for the short- and long-term prospects of the LB technique are also highlighted.

Coordination-assembled myricetin nanoarchitectonics for sustainably scavenging free radicals

Oxidative stress can lead to permanent and irreversible damage to cellular components and even cause cancer and other diseases. Therefore, the development of antioxidative reagents is an important strategy to alleviate chronic diseases and maintain the redox balance in cells. Small-molecule bioactive compounds have exhibited huge therapeutic potential as antioxidants and anti-inflammatory agents. Myricetin (Myr), a well-known natural flavonoid, has drawn wide attention because of its high antioxidant, anti-inflammatory, antimicrobial, and anticancer efficacy. Especially regarding antioxidation, Myr is capable of not only chelating intracellular transition metal ions for removing reactive oxygen species, but also of activating antioxidant enzymes and related signal pathways and, thus, of sustainably scavenging radicals. However, Myr is poorly soluble in water, which limits its bioavailability for biomedical applications, and even its clinical therapeutic potential. The antioxidant peptide glutathione (GSH) plays a role as antioxidant in cells and possesses good hydrophilicity and biocompatibility. However, it is easily metabolized by enzymes. To take advantages of their antioxidation activity and to overcome the abovementioned limitations, GSH, Zn²⁺, and Myr were selected to co-assemble into Myr-Zn²⁺-GSH nanoparticles or nanoarchitectonics. This study offers a new design to harness stable, sustainable antioxidant nanoparticles with high loading capacity, high bioavailability, and good biocompatibility as antioxidants.

There is still plenty of room for layer-by-layer assembly for constructing nanoarchitectonics-based materials and devices

Nanoarchitectonics approaches can produce functional materials from tiny units through combination of various processes including atom/molecular manipulation, chemical conversion, self-assembly/self-organization, microfabrication, and bio-inspired procedures. Existing fabrication approaches can be regarded as fitting into the same concept. In particular, the so-called layer-by-layer (LbL) assembly method has huge potential for preparing applicable materials with a great variety of assembling mechanisms. LbL assembly is a multistep process where different components can be organized in planned sequences while simple alignment options provide access to superstructures, for example helical structures, and anisotropies which are important aspects of nanoarchitectonics. In this article, newly-featured examples are extracted from the literature on LbL assembly discussing trends for composite functional materials according to (i) principles and techniques, (ii) composite materials, and (iii) applications. We present our opinion on the present trends, and the prospects of LbL assembly. While this method has already reached a certain maturity, there is still plenty of room for expanding its usefulness for the fabrication of nanoarchitectonics-based materials and devices.

Identification of Water-Soluble Polymers through Discrimination of Multiple Optical Signals from a Single Peptide Sensor

The pollution of water environments is a worldwide concern. Not only marine pollution by plastic litter, including microplastics, but also the spillage of water-soluble synthetic polymers in wastewater have recently gained increasing attention due to their potential risks to soil and water environments. However, conventional methods to identify polymers dissolved in water are laborious and time-consuming. Here, we propose a simple approach to identify synthetic polymers dissolved in water using a peptide-based molecular sensor with a fluorophore unit. Supervised machine learning of multiple fluorescence signals from the sensor, which specifically or nonspecifically interacted with the polymers, was applied for polymer classification as a proof of principle demonstration. Aqueous solutions containing different polymers or multiple polymer species with different mixture ratios were identified successfully. We found that fluorophore-introduced biomolecular sensors have great potential to provide discriminative information regarding water-soluble polymers. Our approach based on the discrimination of multiple optical signals of water-soluble polymers from peptide-based molecular sensors through machine learning will be applicable to next-generation sensing systems for polymers in wastewater or natural environments.

Peptide nanotube functionalized molecularly imprinted polydopamine based single-use sensor for impedimetric detection of malathion

In the present study, a peptide nanotube functionalized polydopamine (p-Dop) based molecularly imprinted (MIP) sensor system was constructed, characterized, and studied for the impedimetric sensing of an organophosphorus pesticide, malathion (MLT). Electropolymerization in the presence of a template (MLT) was utilized as a convenient and effective strategy to generate imprinted p-Dop films on peptide nanotubes (PNTs) modified graphite electrodes (PGEs). Upon the removal of template, the adsorption of MLT on the specific cavities formed in the MIP film was tracked using electrochemical impedance spectroscopy (EIS). To attain optimal sensor response, experimental conditions, such as film thickness, analyte/functional monomer ratio, and desorption/adsorption time, were analyzed. The obtained MIP(p-Dop)-PNT-PGE sensor exhibited high sensitivity for electrochemical MLT analysis with a wide dynamic detection range of 13 pg mL^-1 - 1.3 µg mL^-1 and a LOD of 1.39 pg mL^-1. The combination of a bio-inspired p-Dop-based MIP with the EIS technique allowed excellent sensitivity and selectivity toward MLT sensing which also yielded high recoveries in real samples. The success of this research strategy in real samples revealed its potential for various future environmental applications.

Recent advances in peptide-based nanomaterials for targeting hypoxia

Hypoxia is a prominent feature of many severe diseases such as malignant tumors, ischemic strokes, and rheumatoid arthritis. The lack of oxygen has a paramount impact on angiogenesis, invasion, metastasis, and chemotherapy resistance. The potential of hypoxia as a therapeutic target has been increasingly recognized over the last decade. In order to treat these disease states, peptides have been extensively investigated due to their advantages in safety, target specificity, and tumor penetrability. Peptides can overcome difficulties such as low drug/energy delivery efficiency, hypoxia-induced drug resistance, and tumor nonspecificity. There are three main strategies for targeting hypoxia through peptide-based nanomaterials: (i) using peptide ligands to target cellular environments unique to hypoxic conditions, such as cell surface receptors that are upregulated in cells under hypoxic conditions, (ii) utilizing peptide linkers sensitive to the hypoxic microenvironment that can be cleaved to release therapeutic or diagnostic payloads, and (iii) a combination of the above where targeting peptides will localize the system to a hypoxic environment for it to be selectively cleaved to release its payload, forming a dual-targeting system. This review focuses on recent developments in the design and construction of novel peptide-based hypoxia-targeting nanomaterials, followed by their mechanisms and potential applications in diagnosis and treatment of hypoxic diseases. In addition, we address challenges and prospects of how peptide-based hypoxia-targeting nanomaterials can achieve a wider range of clinical applications.

Recent advances in dopamine-based materials constructed via one-pot co-assembly strategy

Dopamine-based materials have attracted widespread interest due to the outstanding physicochemical and biological properties. Since the first report on polydopamine (PDA) films, great efforts have been devoted to develop new fabrication strategies for obtaining novel nanostructures and desirable properties. Among them, one-pot co-assembly strategy offers a unique pathway for integrating multiple properties and functions into dopamine-based platform in a single simultaneous co-deposition step. This review focuses on the state of the art development of one-pot multicomponent self-assembly of dopamine-based materials and summarizes various single-step co-deposition approaches, including PDA-assisted adaptive encapsulation, co-assembly of dopamine with other molecules through non-covalent interactions or covalent interactions. Moreover, emerging applications of dopamine-based materials in the fields ranging from sensing, cancer therapy, catalysis, oil/water separation to antifouling are outlined. In addition, some critical remaining challenges and opportunities are discussed to pave the way towards the rational design and applications of dopamine-based materials.

Nanoarchitectonics for Hierarchical Fullerene Nanomaterials

Nanoarchitectonics is a universal concept to fabricate functional materials from nanoscale building units. Based on this concept, fabrications of functional materials with hierarchical structural motifs from simple nano units of fullerenes (C60 and C70 molecules) are described in this review article. Because fullerenes can be regarded as simple and fundamental building blocks with mono-elemental and zero-dimensional natures, these demonstrations for hierarchical functional structures impress the high capability of the nanoarchitectonics approaches. In fact, various hierarchical structures such as cubes with nanorods, hole-in-cube assemblies, face-selectively etched assemblies, and microstructures with mesoporous frameworks are fabricated by easy fabrication protocols. The fabricated fullerene assemblies have been used for various applications including volatile organic compound sensing, microparticle catching, supercapacitors, and photoluminescence systems.

Metal-Coordinated Supramolecular Self-Assemblies for Cancer Theranostics

Metal-coordinated supramolecular nanoassemblies have recently attracted extensive attention as materials for cancer theranostics. Owing to their unique physicochemical properties, metal-coordinated supramolecular self-assemblies can bridge the boundary between traditional inorganic and organic materials. By tailoring the structural components of the metal ions and binding ligands, numerous multifunctional theranostic nanomedicines can be constructed. Metal-coordinated supramolecular nanoassemblies can modulate the tumor microenvironment (TME), thus facilitating the development of TME-responsive nanomedicines. More importantly, TME-responsive organic-inorganic hybrid nanomaterials can be constructed in vivo by exploiting the metal-coordinated self-assembly of a variety of functional ligands, which is a promising strategy for enhancing the tumor accumulation of theranostic molecules. In this review, recent advancements in the design and fabrication of metal-coordinated supramolecular nanomedicines for cancer theranostics are highlighted. These supramolecular compounds are classified according to the order in which the coordinated metal ions appear in the periodic table. Furthermore, the prospects and challenges of metal-coordinated supramolecular self-assemblies for both technical advances and clinical translation are discussed. In particular, the superiority of TME-responsive nanomedicines for in vivo coordinated self-assembly is elaborated, with an emphasis on strategies that enhance the accumulation of functional components in tumors for an ideal theranostic outcome.

Zero-to-Two Nanoarchitectonics: Fabrication of Two-Dimensional Materials from Zero-Dimensional Fullerene

Nanoarchitectonics of two-dimensional materials from zero-dimensional fullerenes is mainly introduced in this short review. Fullerenes are simple objects with mono-elemental (carbon) composition and zero-dimensional structure. However, fullerenes and their derivatives can create various types of two-dimensional materials. The exemplified approaches demonstrated fabrications of various two-dimensional materials including size-tunable hexagonal fullerene nanosheet, two-dimensional fullerene nano-mesh, van der Waals two-dimensional fullerene solid, fullerene/ferrocene hybrid hexagonal nanosheet, fullerene/cobalt porphyrin hybrid nanosheet, two-dimensional fullerene array in the supramolecular template, two-dimensional van der Waals supramolecular framework, supramolecular fullerene liquid crystal, frustrated layered self-assembly from two-dimensional nanosheet, and hierarchical zero-to-one-to-two dimensional fullerene assembly for cell culture.

Structure-Based Programming of Supramolecular Assemblies in Living Cells for Selective Cancer Cell Inhibition

Here we report on the design, synthesis, and assembly of an enzymatic programmable peptide system inspired by endocytic processes to induce molecular assemblies formation spatiotemporally in living cancer cells, resulting in glioblastoma cell death mainly in necroptosis. Our results indicate the stability and glycosylation of molecules play an essential role in determining the final bioactivity. Detailed mechanistic studies by CLSM, Flow cytometry, western blot, and Bio-EM suggest the site-specific formation of assemblies, which could induce the LMP and activate the downstream cell death pathway. Moreover, we also demonstrate that our strategy can boost the activity of commercial chemotherapy drug by escaping lysosome sequestration. We expected this work would be expanded towards artificial intelligent biomaterials for cancer therapy and imaging precisely.

Supramolecular Nanodrugs Based on Covalent Assembly of Therapeutic Peptides toward In Vitro Synergistic Anticancer Therapy

Therapeutic peptides have attracted significant attention in clinical applications due to their advantages in biological origination and good biocompatibility. However, the therapeutic performance of peptides is usually hindered by their short half-lives in blood and inferior activity. Herein, supramolecular nanodrugs of therapeutic peptides are constructed by covalent assembly of chemotherapeutic peptides through genipin cross-linking. The resulting nanodrugs have intense absorbance in the near-infrared region and high photothermal conversion efficiencies, leading to the possibility of photothermal therapy. The combination of photothermal therapy and chemotherapy using the nanodrugs shows synergistic therapeutic effects on cancer cells. Hence, covalent assembly not only maintains the chemotherapeutic activities of the peptides but also triggers supramolecular photothermal effects, demonstrating that the covalent assembly of therapeutic peptides through genipin cross-linking is an efficient approach in constructing supramolecular nanodrugs toward synergistic anticancer therapy.

Control of parallel versus antiparallel molecular arrangements in crystalline assemblies of alkyl β-cellulosides

HYPOTHESIS

The precise control of parallel versus antiparallel molecular arrangements in synthetic assemblies of biorelated molecules is an attractive research focus from both scientific and technological viewpoints. However, little is known about cellulose-based synthetic assemblies. We hypothesized the existence of potential parameters, such as temperature, salt concentration, salt species, and solvent species, for controlling the molecular arrangement in assemblies of alkyl β-cellulosides with different alkyl chain lengths.

EXPERIMENTAL

The self-assembly of alkyl β-cellulosides was triggered by neutralization-induced water insolubilization. The crystal structures of the cellulose moieties in the assemblies were characterized by attenuated total reflection-Fourier transform infrared absorption spectroscopy and wide-angle X-ray diffraction measurements. The morphologies of the assemblies were also characterized by scanning electron, atomic force, and transmission electron microscopy.

FINDINGS

The temperature for the self-assembly, the concentration and species of inorganic salt in the self-assembly solution, and the solvent species (namely, the addition of water-miscible organic solvents into the self-assembly solution) strongly affected the molecular arrangement of the assemblies. The observations suggested that hydrophobic effects between the alkyl groups of the alkyl β-cellulosides and/or interactions of the alkyl β-cellulosides with solvent species were potential factors for controlling the molecular arrangement.

Nanoarchitectonics on living cells

In this review article, the recent examples of nanoarchitectonics on living cells are briefly explained. Not limited to conventional polymers, functional polymers, biomaterials, nanotubes, nanoparticles (conventional and magnetic ones), various inorganic substances, metal-organic frameworks (MOFs), and other advanced materials have been used as components for nanoarchitectonic decorations for living cells. Despite these artificial processes, the cells can remain active or remain in hibernation without being killed. In most cases, basic functions of the cells are preserved and their resistances against external assaults are much enhanced. The possibilities of nanoarchitectonics on living cells would be high, equal to functional modifications with conventional materials. Living cells can be regarded as highly functionalized objects and have indispensable contributions to future materials nanoarchitectonics.

Co-assembled gold nanorod@tripeptide core-shell nanospheres for aqueous Hg2+ removal

The construction of peptide and metal nanoparticles hybrid is attractive to explore their synergistic properties and applications extensively. However, it remains a challenge to fabricate a well-defined and size-controllable short peptide/Au nanoparticles hybrid. Here, we report a facile and flexible co-assembly strategy for the construction of tripeptide coated Au nanorods (AuNRs). The tripeptide (Phe-Phe-Cys, FFC) grows via covalently crosslinking to form spheres. The size of the core@shell nanospheres can be controlled by modulating the amount or size of AuNRs. Especially, the concentration of AuNRs fixes the amount of seeds, which further affect the local concentration of FFC on the surface of AuNRs seed, leading to a narrower diameter of hybrid compared to FFC spheres. Moreover, owing to their synergistic effects, this hybrid exhibits a good adsorption capacity of Hg²⁺ from aqueous solutions by electrostatic interaction and forming into Au/Hg amalgam. This strategy could be extended to the fabrication of other biomolecules and metal nanoparticle hybrids with diverse functions.

Nanoarchitectonics: what's coming next after nanotechnology?

In science and technology today, the crucial importance of the regulation of nanoscale objects and structures is well recognized. The production of functional material systems using nanoscale units can be achieved via the fusion of nanotechnology with the other research disciplines. This task is a part of the emerging concept of nanoarchitectonics, which is a concept moving beyond the area of nanotechnology. The concept of nanoarchitectonics is supposed to involve the architecting of functional materials using nanoscale units based on the principles of nanotechnology. In this focus article, the essences of nanotechnology and nanoarchitectonics are first explained, together with their historical backgrounds. Then, several examples of material production based on the concept of nanoarchitectonics are introduced via several approaches: (i) from atomic switches to neuromorphic networks; (ii) from atomic nanostructure control to environmental and energy applications; (iii) from interfacial processes to devices; and (iv) from biomolecular assemblies to life science. Finally, perspectives relating to the final goals of the nanoarchitectonics approach are discussed.

Disassembly and reassembly of diphenylalanine crystals through evaporation of solvent

HYPOTHESIS

Crystalline self-assemblies of diphenylalanine (FF) are since long back considered to be related to Alzheimer's disease. An improved understanding of the mechanism behind the formation of such structures can lead to strategies for investigating the dynamic processes of assembly and disassembly of FF.

EXPERIMENT

The assembly, disassembly and reassembly of FF crystals are influenced by the solvent composition and can be triggered by evaporation of solvent. In this work these processes are directly monitored, and the structures obtained are analyzed.

FINDINGS

The role of the solvent for assembly, disassembly and reassembly of diphenylalanine crystals has been demonstrated. The initial crystal structure formed via self-assembly of FF monomers can be transformed into needle-like crystals and further to hollow hexagonal microtubes through evaporation of the solvent. It is shown that all the assembly-disassembly processes are spontaneous and driven by thermodynamics. It is also found that some of the crystalline structures exhibit optical waveguiding properties.

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.

Embedment of Quantum Dots and Biomolecules in a Dipeptide Hydrogel Formed In Situ Using Microfluidics

As low-molecular-weight hydrogelators, dipeptide hydrogel materials are suited for embedding multiple organic molecules and inorganic nanoparticles. Herein, a simple but precisely controllable method is presented that enables the fabrication of dipeptide-based hydrogels by supramolecular assembly inside microfluidic channels. Water-soluble quantum dots (QDs) as well as premixed porphyrins and a dipeptide in dimethyl sulfoxide (DMSO) were injected into a Y-shaped microfluidic junction. At the DMSO/water interface, the confined fabrication of a dipeptide-based hydrogel was initiated. Thereafter, the as-formed hydrogel flowed along a meandering microchannel in a continuous fashion, gradually completing gelation and QD entrapment. In contrast to hydrogelation in conventional test tubes, microfluidically controlled hydrogelation led to a tailored dipeptide hydrogel regarding material morphology and nanoparticle distribution.

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.

The impact of thermal history on the structure of glycylalanylglycine ethanol/water gels

This work revisits several open questions regarding the mechanisms of GAG fibril formation and structure as a function of temperature. The authors recently hypothesized that there is a solubility limit of GAG in ethanol/water that induces self-assembly. In other words, not all peptides can participate in fibrillization and some fraction is still soluble in solution. We show via FTIR spectroscopy that, indeed, free peptides are still present in solution after fibril formation, strongly supporting the solubility model. Furthermore, previous work showed GAG self-assembled into right-handed (phase I) or left-handed (phase II) chiral structures depending on temperature. In this study, we analyze the crystalline structure of phase I and II gels via WAXS and SAXS to compare their crystalline structures and order. Rheological measurements were used to investigate the response of the fibrillar network to temperature. They reveal that the ability of the peptide to self-assemble depends on the solubility at a given temperature and not on thermal history. Furthermore, the gel softening point, the linear viscoelastic gel microstructure, and relaxation spectrum are very similar between phase I and phase II. Overall, the temperature only affects the chirality of the fibrils and the formation kinetics.

Affinity-based thermoresponsive fluorescence switching of proteins conjugated with a polymer-binding peptide

The affinity-based thermoresponsive fluorescence switching of proteins conjugated with a polymer-binding peptide is demonstrated. The specific affinity of the peptide and thermoresponsive structural transitions of the polymer are essential for reliable fluorescence switching behavior.

Solvent Effect on Supramolecular Self-Assembly of Chlorophylls a on Chemically Reduced Graphene Oxide

Solvent plays an important role in the surface interaction of molecules. In this study, we use "chlorophyll a", an archetypical molecule, to investigate its supramolecular self-assembly with chemically reduced graphene oxide in three different types of solvents: polar protic, polar aprotic, and non-polar. It was observed that only a polar protic solvent that can donate protons facilitates the hydrogen bonding between chlorophyll a and chemically reduced graphene oxide nanosheets in a hybrid system. The formation of hydrogen bonds further initiates the other non-covalent interactions such as π-π stacking and hydrophobic interaction, which altogether play a key driving force for supramolecular self-assembly of chlorophylls on chemically reduced graphene oxides. The experimental results are strongly supported by density functional theory calculations, which show robust electron coupling between chlorophylls and chemically reduced graphene oxide.

Supramolecular Chiral Nanoarchitectonics

Exploration of molecular functions and material properties based on the control of chirality would be a scientifically elegant approach. Here, the fabrication and function of chiral-featured materials from both chiral and achiral components using a supramolecular nanoarchitectonics concept are discussed. The contents are classified in to three topics: i) chiral nanoarchitectonics of rather general molecular assemblies; ii) chiral nanoarchitectonics of metal-organic frameworks (MOFs); iii) chiral nanoarchitectonics in liquid crystals. MOF structures are based on nanoscopically well-defined coordinations, while mesoscopic orientations of liquid-crystalline phases are often flexibly altered. Discussion on the effects and features in these representative materials systems with totally different natures reveals the universal importance of supramolecular chiral nanoarchitectonics. Amplification of chiral molecular information from molecules to materials-level structures and the creation of chirality from achiral components upon temporal statistic fluctuations are universal, regardless of the nature of the assemblies. These features are thus surely advantageous characteristics for a wide range of applications.