Mimicking Primitive Photobacteria: Sustainable Hydrogen Evolution Based on Peptide-Porphyrin Co-Assemblies with a Self-Mineralized Reaction Center

A Cost-Effective Hemin-Based Artificial Enzyme Allows for Practical Applications

Nanomaterials excel in mimicking the structure and function of natural enzymes while being far more interesting in terms of structural stability, functional versatility, recyclability, and large-scale preparation. Herein, the story assembles hemin, histidine analogs, and G-quadruplex DNA in a catalytically competent supramolecular assembly referred to as assembly-activated hemin enzyme (AA-heminzyme). The catalytic properties of AA-heminzyme are investigated both in silico (by molecular docking and quantum chemical calculations) and in vitro (notably through a systematic comparison with its natural counterpart horseradish peroxidase, HRP). It is found that this artificial system is not only as efficient as HRP to oxidize various substrates (with a turnover number kcat of 115 s-1) but also more practically convenient (displaying better thermal stability, recoverability, and editability) and more economically viable, with a catalytic cost amounting to <10% of that of HRP. The strategic interest of AA-heminzyme is further demonstrated for both industrial wastewater remediation and biomarker detection (notably glutathione, for which the cost is decreased by 98% as compared to commercial kits).

Self-assembled π-conjugated chromophores: preparation of one- and two-dimensional nanostructures and their use in photocatalysis

Photocatalytic systems have attracted research interest as a clean approach to generate energy from abundant sunlight. In this context, developing efficient and robust photocatalytic structures is crucial. Recently, self-assembled organic chromophores have entered the stage as alternatives to both molecular systems and (in)organic semiconductors. Nanostructures made of self-assembled π-conjugated dyes offer, on the one hand, molecular customizability to tune their optoelectronic properties and activities and on the other hand, provide benefits from heterogeneous catalysis that include ease of separation, recyclability and improved photophysical properties. In this contribution, we present recent achievements in constructing supramolecular photocatalytic systems made of chromophores for applications in water splitting, H2O2 evolution, CO2 reduction, or environmental remediation. We discuss strategies that can be used to prepare ordered photocatalytic systems with an emphasis on the effect of packing between the dyes and the resulting photocatalytic activity. We further showcase supramolecular strategies that allow interfacing the organic nanostructures with co-catalysts, molecules, polymers, and (in)organic materials. The principles discussed here are the foundation for the utilization of these self-assembled materials in photocatalysis.

Pt(II)/Pd(II)-Based Metallosupramolecular Architectures as Light Harvesting Systems and their Applications

The development of artificial light-harvesting systems mimicking the natural photosynthesis method is an ever-growing field of research. Numerous systems such as polymers, metal complexes, POFs, COFs, supramolecular frameworks etc. have been fabricated to accomplish more efficient energy transfer and storage. Among them, the supramolecular coordination complexes (SCCs) formed by non-covalent metal-ligand interaction, have shown the capacity to not only undergo single and multistep energy migration but also to utilize the harvested energy for a wide variety of applications such as photocatalysis, tunable emissive systems, encrypted anti-counterfeiting materials, white light emitters etc. This review sheds light on the light-harvesting behavior of both the 2D metallacycles and 3D metallacages where design ingenuity has been executed to afford energy harvesting by both donor ligands as well as metal acceptors.

Bioinspired Self-Assembly of Metalloporphyrins and Polyelectrolytes into Hierarchical Supramolecular Nanostructures for Enhanced Photocatalytic H2 Production in Water

Polypeptides, as natural polyelectrolytes, are assembled into tailored proteins to integrate chromophores and catalytic sites for photosynthesis. Mimicking nature to create the water-soluble nanoassemblies from synthetic polyelectrolytes and photocatalytic molecular species for artificial photosynthesis is still rare. Here, we report the enhancement of the full-spectrum solar-light-driven H2 production within a supramolecular system built by the co-assembly of anionic metalloporphyrins with cationic polyelectrolytes in water. This supramolecular photocatalytic system achieves a H2 production rate of 793 and 685 μmol h-1  g-1 over 24 h with a combination of Mg or Zn porphyrin as photosensitizers and Cu porphyrin as a catalyst, which is more than 23 times higher than that of free molecular controls. With a photosensitizer to catalyst ratio of 10000 : 1, the highest H2 production rate of >51,700 μmol h-1  g-1 with a turnover number (TON) of >1,290 per molecular catalyst was achieved over 24 h irradiation. The hierarchical self-assembly not only enhances photostability through forming ordered stackings of the metalloporphyrins but also facilitates both energy and electron transfer from antenna molecules to catalysts, and therefore promotes the photocatalysis. This study provides structural and mechanistic insights into the self-assembly enhanced photostability and catalytic performance of supramolecular photocatalytic systems.

Hierarchically Organized Cocrystal of Tetra-Anionic Porphyrin and Di-Cationic Viologen: Ion Conformations, Supramolecule Interactions, and Porphyrin Arrays

Ionic co-assembly of tetra-anionic porphyrins has been extensively researched in the construction of hierarchically organized architectures with potential application value in organic semiconductors, sunlight catalysts and supramolecular chirality systems. However, such architectures are difficult to grow to a size suitable for single-crystal X-ray diffraction (SCXRD); the lack of single-crystal structures of these architectures leads to challenges in gaining deeper comprehension about that. This study reports a hierarchically organized cocrystal of meso-tetra(4-sulfonato-phenyl)-porphyrin (TSPP^4- ) and N, N'-diethyl-viologen (DEV²⁺ ), wherein wave-like and saddle-like TSPP^4- ions co-aggregate at a stoichiometric ratio of 1 : 2 to form unique porphyrin arrays; the spectrum characteristics and calculated coulombic exciton coupling energy show that these porphyrin arrays are J-aggregates. We prove that the distortion of porphyrin ring of TSPP^4- strongly correlates with the deflection of its phenyl groups. The crystal comprises six different ionic conformations, and the multiplicity of ionic conformation leads to intricate supramolecular interactions.

Biomimetic mineralization based on self-assembling peptides

Biomimetic science has attracted great interest in the fields of chemistry, biology, materials science, and energy. Biomimetic mineralization is the process of synthesizing inorganic minerals under the control of organic molecules or biomolecules under mild conditions. Peptides are the motifs that constitute proteins, and can self-assemble into various hierarchical structures and show a high affinity for inorganic substances. Therefore, peptides can be used as building blocks for the synthesis of functional biomimetic materials. With the participation of peptides, the morphology, size, and composition of mineralized materials can be controlled precisely. Peptides not only provide well-defined templates for the nucleation and growth of inorganic nanomaterials but also have the potential to confer inorganic nanomaterials with high catalytic efficiency, selectivity, and biotherapeutic functions. In this review, we systematically summarize research progress in the formation mechanism, nanostructural manipulation, and applications of peptide-templated mineralized materials. These can further inspire researchers to design structurally complex and functionalized biomimetic materials with great promising applications.

Bioinspired porphyrin-peptide supramolecular assemblies and their applications

Inspired by the hierarchical chiral assembly of porphyrin-proteins in photosynthetic systems, the hierarchical self-assembly of porphyrin-amino acids/peptides provides a novel strategy for constructing functional materials. How to artificially simulate the assembly of porphyrins, proteins, and other cofactors in the photosynthesis system to obtain persistent strong light capture, charge separation and catalytic reactions has become an important concern in the construction of biomimetic photosynthesis systems. This paper summarizes the different assembly strategies adopted in recent years, the effects of driving forces on self-assembly, and the application of porphyrin-peptides in catalysis and biomedicine, and briefly discusses the challenges and prospects for future research.

A Bioinspired Light Harvesting System in Aqueous Medium: Highly Efficient Energy Transfer through the Self Assembly of β-Sheet Nanostructures of Poly-d-Lysine

Nature has beautifully assembled its light harvesting pigments within protein scaffolds, which ensures a very high energy transfer. Designing a highly efficient artificial bioinspired light harvesting system (LHS) thus requires the nanoscale spatial orientation and electronic control of the associated chromophores. Although DNA has been used as a scaffold to organize chromophores, proteins or polypeptides, however, are very rarely explored. Here, we have developed a highly efficient, artificial, bioinspired LHS using polypeptide (poly-d-lysine, PDL) nanostructures making use of their β-sheet structure in an aqueous alkaline medium. The chromophores used herein are compatible for an energy transfer process and are nonfluorescent in an aqueous medium but exhibit high fluorescence intensity when bound to the nanostructure of PDL. The close proximity of the chromophores results in an energy transfer efficiency of ∼92% besides generating white light emission at a particular molar ratio between the chromophores.

Porphyrins and phthalocyanines as biomimetic tools for photocatalytic H2 production and CO2 reduction

The increasing energy demand and environmental issues caused by the over-exploitation of fossil fuels render the need for renewable, clean, and environmentally benign energy sources unquestionably urgent. The zero-emission energy carrier, H₂ is an ideal alternative to carbon-based fuels especially when it is generated photocatalytically from water. Additionally, the photocatalytic conversion of CO₂ into chemical fuels can reduce the CO₂ emissions and have a positive environmental and economic impact. Inspired by natural photosynthesis, plenty of artificial photocatalytic schemes based on porphyrinoids have been investigated. This review covers the recent advances in photocatalytic H₂ production and CO₂ reduction systems containing porphyrin or phthalocyanine derivatives. The unique properties of porphyrinoids enable their utilization both as chromophores and as catalysts. The homogeneous photocatalytic systems are initially described, presenting the various approaches for the improvement of photosensitizing activity and the enhancement of catalytic performance at the molecular level. On the other hand, for the development of the heterogeneous systems, numerous methods were employed such as self-assembled supramolecular porphyrinoid nanostructures, construction of organic frameworks, combination with 2D materials and adsorption onto semiconductors. The dye sensitization on semiconductors opened the way for molecular-based dye-sensitized photoelectrochemical cells (DSPECs) devices based on porphyrins and phthalocyanines. The research in photocatalytic systems as discussed herein remains challenging since there are still many limitations making them unfeasible to be used at a large scale application before finding a large-scale application.

"On/Off" Switchable Sequential Light-Harvesting Systems Based on Controllable Protein Nanosheets for Regulation of Photocatalysis

A controllable protein nanostructures-based "On/Off" switchable artificial light-harvesting system (LHS) with sequential multistep energy transfer and photocatalysis was reported herein for mimicking the natural LHS in both structure and function. Single-layered protein nanosheets were first constructed via a reversible covalent self-assembly strategy using cricoid stable protein one (SP1) as building blocks to realize an ordered arrangement of pigments. Fluorescent chromophores like carbon dots (CDs) can be precisely distributed on the protein nanosheets superficially via electrostatic interactions and make the ratio between donors and acceptors adjustable. After being anchored with a photocatalysis center (eosin-5-isothiocyanate, EY), the constructed LHS could sequentially transfer energy between two kinds of chromophores (CD1 and CD2), and further transfer to EY center with a high efficiency of 84%. Interestingly, the Förster resonance energy transfer (FRET) process of our LHS could be reversibly "On/Off" switched by the redox regulated assembly and disassembly of SP1 building blocks. Moreover, the LHS has been further proved to promote the yield of a model cross-coupling hydrogen evolution reaction and regulate the process of the reaction with the FRET process "On/Off" state.

Functional Nano-Objects by Electrostatic Self-Assembly: Structure, Switching, and Photocatalysis

The design of functional nano-objects by electrostatic self-assembly in solution signifies an emerging field with great potential. More specifically, the targeted combination of electrostatic interaction with other effects and interactions, such as the positioning of charges on stiff building blocks, the use of additional amphiphilic, π−π stacking building blocks, or polyelectrolytes with certain architectures, have recently promulgated electrostatic self-assembly to a principle for versatile defined structure formation. A large variety of architectures from spheres over rods and hollow spheres to networks in the size range of a few tenths to a few hundred nanometers can be formed. This review discusses the state-of-the-art of different approaches of nano-object formation by electrostatic self-assembly against the backdrop of corresponding solid materials and assemblies formed by other non-covalent interactions. In this regard, particularly promising is the facile formation of triggerable structures, i.e. size and shape switching through light, as well as the use of electrostatically assembled nano-objects for improved photocatalysis and the possible solar energy conversion in the future. Lately, this new field is eliciting an increasing amount of understanding; insights and limitations thereof are addressed in this article. Special emphasis is placed on the interconnection of molecular building block structures and the resulting nanoscale architecture via the key of thermodynamics.

Photolytic Removal of Red Blood Cell Membranes Camouflaged on Nanoparticles for Enhanced Cellular Uptake and Combined Chemo-Photodynamic Inhibition of Cancer Cells

Biomimetic therapeutics offer great potential for drug delivery that avoids immune recognition. However, the coated cell membrane usually hinders the cellular uptake of nanoparticles; thus, structure-changeable formulations have attracted increasing attention. Herein, we report photolytic pyropheophorbide a (PA)-inserted red blood cell (RBC) membrane-camouflaged curcumin dimeric prodrug (CUR₂-TK)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles [(CUR₂-TK)-PLGA@RBC-PA] for enhanced cancer therapy. In these nanoparticles, the inner core was constructed using PLGA and loaded with our synthesized reactive oxygen species (ROS)-responsive cleavable curcumin dimeric prodrug (CUR₂-TK). The nanoparticles generated ROS in response to the light irradiation attributed to the incorporated PA. The ROS further triggered the lysis of the cell membrane and exposed the nanoparticles for enhanced tumor cellular uptake, and the ROS also cleaved CUR₂-TK for controlled CUR drug release. Moreover, the ROS performed photodynamic therapy (PDT). The chemotherapy and PDT produced a combined effect in the treatment of cancer cells, thus enhancing anticancer therapeutic efficacy.

Self-Assembled Porphyrin Nanoleaves with Unique Crossed Transportation of Photogenerated Carriers to Enhance Photocatalytic Hydrogen Production

The preparation of self-assembled porphyrins with orderly stacked nanostructures for emulating natural photosynthesis has stimulated extensive efforts to optimize the energy conversion efficiency. However, the elucidation of how orderly stacked structures promote photocatalysis at the molecular level remains a great challenge. Here, unique porphyrin nanoleaves with designed and ordered structure are synthesized and show a hydrogen evolution rate higher than that of commercial powder. Photodeposition of cocatalysts and Kelvin probe force microscopy measurement suggest selective aggregation of photogenerated electrons and holes at different active sites. Combined with theoretical calculations, we find that the orderly packing changes molecular symmetry and induces a molecular dipole, which increases linearly along the π-π stacking direction and forms a strong built-in electric field. The built-in electric field drives photogenerated electrons and holes for the unique crossed transportation along different directions. These findings reveal how orderly stacked structures promote photocatalysis and provide a novel approach for highly efficient water splitting.

Biomimetic Nanozymes Based on Coassembly of Amino Acid and Hemin for Catalytic Oxidation and Sensing of Biomolecules

Nanoassemblies based on self-assembly of biological building blocks are promising in mimicking the nanostructures, properties, and functionalities of natural enzymes. However, it remains a challenge to design of biomimetic nanozymes with tunable nanostructures and enhanced catalytic activities starting from simple biomolecules. Herein, the construction of nanoassemblies through coassembly of an amphiphilic amino acid and hemin is reported. The nanostructures and morphologies of the resulting nanoassemblies are readily controlled by tuning the molar ratio between the amino acid and hemin, thus leading to tailored peroxidase-mimicking activities of the nanoassemblies. Importantly, the optimized nanoassemblies exhibit a remarkable catalytic efficiency that is comparable to the natural counterpart when considering molecular mass along with good robustness in multiple catalytic cycles. The nanoassemblies are effectively integrated as biomimetic nanozymes in a sensing system for catalytic detection of glucose. Therefore, this work demonstrates that nanozymes with advanced catalytic capabilities can be constructed by self-assembly of minimalist biological building blocks and may thus promote the rational design and catalytic applications of biomimetic nanozymes.

Peptide-Tetrapyrrole Supramolecular Self-Assemblies: State of the Art

The covalent and noncovalent association of self-assembling peptides and tetrapyrroles was explored as a way to generate systems that mimic Nature's functional supramolecular structures. Different types of peptides spontaneously assemble with porphyrins, phthalocyanines, or corroles to give long-range ordered architectures, whose structure is determined by the features of both components. The regular morphology and ordered molecular arrangement of these systems enhance the photochemical properties of embedded chromophores, allowing applications as photo-catalysts, antennas for dye-sensitized solar cells, biosensors, and agents for light-triggered therapies. Chemical modifications of peptide and tetrapyrrole structures and control over the assembly process can steer the organization and influence the properties of the resulting system. Here we provide a review of the field, focusing on the assemblies obtained from different classes of self-assembling peptides with tetrapyrroles, their morphologies and their applications as innovative functional materials.

Recent Progress in Ionic Coassembly of Cationic Peptides and Anionic Species

Peptide assembly has been extensively exploited as a promising platform for the creation of hierarchical nanostructures and tailor-made bioactive materials. Ionic coassembly of cationic peptides and anionic species is paving the way to provide particularly important contribution to this topic. In this review, the recent progress of ionic coassembly soft materials derived from the electrostatic coupling between cationic peptides and anionic species in aqueous solution is systematically summarized. The presentation of this review starts from a brief background on the general importance and advantages of peptide-based ionic coassembly. After that, diverse combinations of cationic peptides with small anions, macro- and/or oligo-anions, anionic polymers, and inorganic polyoxometalates are described. Emphasis is placed on the hierarchical structures, value-added properties, and applications. The molecular design of cationic peptides and the general principles behind the ionic coassembled structures are discussed. It is summarized that the combination of interesting and unique characteristics that arise both from the chemical diversity of peptides and the wide range of anionic species may contribute in a variety of output, including drug delivery, tissue engineering, gene transfection, and antibacterial activity. The emergent new phenomena and findings are illustrated. Finally, the outlook for the peptide-based ionic coassembly systems is also presented.

Peptide-mediated porphyrin based hierarchical complexes for light-to-chemical conversion

We present a new strategy for the biomimetic preparation of integrated photoactive complexes consisting of light harvesting and electron separation/transfer components via the hierarchical assembly of porphyrin and platinum nanoparticles on the surface of short-peptide self-assembled structures. The complexes can catalyze the conversion of visible light energy into chemical energy in the absence of an electron mediator and store it as nicotinamide adenine dinucleotide (NADH). This provides a promising step towards artificial photosystems through precisely controlled interactions of light-capturing agents, electron separators and biomolecules.

Intelligent Bimetallic Nanoagents as Reactive Oxygen Species Initiator System for Effective Combination Phototherapy

Phototherapy is a promising oncotherapy method. However, there are various factors greatly restricted phototherapy development, including poor tumor-specific accumulation, the hypoxia in solid tumor, and the systemic phototoxicity of photosensitizer. Herein, a tumor microenvironment (TME)-responsive intelligent bimetallic nanoagents (HSA-Pd-Fe-Ce6 NAs) composed of human serum albumin (HSA), palladium-iron (Pd-Fe) bimetallic particles, and chlorin e6 (Ce6) was designed for effective combination phototherapy. The Pd-Fe part in the HSA-Pd-Fe-Ce6 NAs would react with the endogenous hydrogen peroxide (H₂O₂) in an acidic ambiance within tumor to generate cytotoxic superoxide anion free radical through the “Fenton-like reaction.” H₂O₂, coupled with highly toxic singlet oxygen (¹O₂) caused by the Ce6 component under the irradiation of 660 nm laser, resulted in synergistic cancer therapy effects in hypoxia surroundings. Besides, this nanoagents could result in hyperpyrexia-induced cell apoptosis because of superior absorption performance in near-infrared wavelength window bringing about excellent photothermal conversion efficiency. The cell cytotoxicity results showed that the survival rate after treated by 40 μg mL^–1 nanoagents was only 17%, which reveals that the HSA-Pd-Fe-Ce6 NAs had the advantage of efficient and controllable phototherapy. In short, it exhibited excellent hypoxia-resistant combination phototherapy efficacy in vitro. Therefore, the multifunctional nanoagents are powerful and provide a new avenue for effective combination phototherapy.

Multifunctional Antimicrobial Biometallohydrogels Based on Amino Acid Coordinated Self-Assembly

There is a real need for new antibiotics against self-evolving bacteria. One option is to use biofriendly broad-spectrum and mechanically tunable antimicrobial hydrogels that can combat multidrug-resistant microbes. Whilst appealing, there are currently limited options. Herein, broad-spectrum antimicrobial biometallohydrogels based on the self-assembly and local mineralization of Ag⁺ -coordinated Fmoc-amino acids are reported. Such biometallohydrogels have the advantages of localized delivery and sustained release, reduced drug dosage and toxicity yet improved bioavailability, prolonged drug effect, and tunable mechanical strength. Furthermore, they can directly interact with the cell walls and membrane, resulting in the detachment of the plasma membrane and leakage of the cytoplasm. This leads to cell death, triggering a significant antibacterial effect against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria in cells and mice. This study paves the way for developing a multifunctional integration platform based on simple biomolecules coordinated self-assembly toward a broad range of biomedical applications.

Multi-component supramolecular gels induce protonation of a porphyrin exciplex to achieve improved collective optical properties for effective photocatalytic hydrogen generation

Two-porphyrin supramolecular gels induce exciplex formation, protonation and J-aggregation of porphyrins, which render a smaller bandgap, charge separation and good photocatalytic properties.

Water-Soluble, Zwitterionic Poly-photosensitizers as Carrier-Free, Photosensitizer-Self-Delivery System for in Vivo Photodynamic Therapy

Polymeric nanoparticles (NPs) have been widely established to deliver most of the hydrophobic chemo-drugs or photosensitizers (PSs) for cancer therapy. However, this strategy is usually hindered by the relatively low drug loading capacity and the undesired toxicity as well as the immunogenicity caused by the nontherapeutic, polymeric carriers. The carrier-free, drug self-delivery systems, in which the chemo-drugs or their prodrugs themselves formed the NPs without the addition of nontherapeutic carriers, have been extensively developed to achieve a high drug loading capacity and low systemic toxicity. However, most of the driving forces to form the NPs were based on the strong hydrophobic interactions, which were the undesired forces for the porphyrin-based hydrophobic PSs due to the parasitic aggregation-caused quenching effect. Herein, the zwitterionic, water-soluble, and reactive oxygen species (ROS)-cleavable poly-photosensitizers (pPSs) were prepared by the polymerization method, which spontaneously introduced different charges associated with the "desired electrostatic effect" and reduced the "undesired aggregation" by separating the PS monomers using flexible and ROS-cleavable linkers. The obtained pPS could be self-assembled into the nanocomplexes based on the electrostatic effect with a high PS loading capacity, improved singlet oxygen generation ability, and efficient phototoxicity. Upon poly(ethylene glycol) (PEG) or hyaluronic acid (HA) coating on the surface, both pPS/PEG and pPS/HA complexes exhibited enhanced stability under physiological environments and excellent in vivo antitumor efficacy. Moreover, HA-coated complexes also exhibited active tumor targeting. Such a polymerization strategy comprehensively addressed the parasitic issues for the hydrophobic PS self-delivery system in the photodynamic therapy area.

Tuning the Supramolecular Structures of Metal-Free Porphyrin via Surfactant Assisted Self-Assembly to Enhance Photocatalytic Performance

Metal-free porphyrin with good planarity is beneficial to π-π stack interactions, which promotes electron coupling and the separation and transfer of photogenerated carriers. It is necessary to develop metal-free porphyrin-based photocatalysts and exploit the photocatalytic mechanism. Herein, metal-free porphyrin (5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, TCPP) was self-assembled through an acid-based neutralization reaction and mixing dual-solvents under surfactants to form different aggregates. Morphology structures, optical and optoelectronic properties of the TCPP aggregates were characterized in detail. TCPP self-assemblies showed higher photocatalytic activities for the degradation of phenol under visible light than untreated TCPP powders, and the aggregates of nanorods formed through the acid-based neutralization reaction in the presence of hexadecyl trimethyl ammonium bromide (CTAB) possessed 2.6 times more activity than the nanofiber aggregates formed through mixing dual-solvents. It was proved that self-assembly methods are crucial for controlling the aggregation of porphyrins to form different aggregations, which have a profound impact on the photocatalytic activity.

Self-assembling peptide-based nanodrug delivery systems

Self-assembling peptide-based nanodrug delivery systems (NDDs), consisting of naturally occurring amino acids, not only share the advantages of traditional nanomedicine but also possess the unique properties of excellent biocompatibility, biodegradability, flexible responsiveness, specific biological function, and synthetic feasibility. Physical methods, enzymatic reaction, chemical reaction, and biosurface induction can yield versatile peptide-based NDDs; flexible responsiveness is their main advantage. Different functional peptides and abundant covalent modifications endow such systems with precise controllability and multifunctionality. Inspired by the above merits, researchers have taken advantage of the self-assembling peptide-based NDDs and achieved the accurate delivery of drugs to the lesion site. The present review outlines the methods for designing self-assembling peptide-based NDDs for small-molecule drugs, with an emphasis on the different drug delivery strategies and their applications in using peptides and peptide conjugates.

Photoactive properties of supramolecular assembled short peptides

Bioinspired nanostructures can be the ideal functional smart materials to bridge the fundamental biology, biomedicine and nanobiotechnology fields. Among them, short peptides are among the most preferred building blocks as they can self-assemble to form versatile supramolecular architectures displaying unique physical and chemical properties, including intriguing optical features. Herein, we discuss the progress made over the past few decades in the design and characterization of optical short peptide nanomaterials, focusing on their intrinsic photoluminescent and waveguiding performances, along with the diverse modulation strategies. We review the complicated optical properties and the advanced applications of photoactive short peptide self-assemblies, including photocatalysis, as well as photothermal and photodynamic therapy. The diverse advantages of photoactive short peptide self-assemblies, such as eco-friendliness, morphological and functional flexibility, and ease of preparation and modification, endow them with the capability to potentially serve as next-generation, bio-organic optical materials, allowing the bridging of the optics world and the nanobiotechnology field.

Highly Efficient Catalytic Performances of Nitro Compounds and Morin via Self-Assembled MXene-Pd Nanocomposites Synthesized through Self-Reduction Strategy

With development of the society, the problem of environmental pollution is becoming more and more serious. There is the urgent need to develop a new type of sustainable green material for degradable pollutants. However, the conventional preparation method is limited by conditions such as cumbersome operation, high energy consumption, and high pollution. Here, a simple method named self-reduction has been proposed, to synthesize highly efficient catalytic nitro compounds and morin self-assembled MXene-Pd nanocomposites. Palladium nanoparticles were grown in situ on MXene nanosheets to form MXene@PdNPs. MXene@PdNPs composites with different reaction times were prepared by adjusting the reduction reaction time. In particular, MXene@PdNPs20 exhibited a high catalytic effect on 4-NP and 2-NA, and the first-order rate constants of the catalysis were 0.180 s-1 and 0.089 s-1, respectively. It should be noted that after eight consecutive catalytic cycles, the conversion to catalyze 4-NP was still greater than 94%, and the conversion to catalyze 2-NA was still greater than 91.8%. Therefore, the research of self-assembled MXene@PdNPs nanocomposites has important potential value for environmental management and sustainable development of human health, and provides new clues for the future research of MXene-based new catalyst materials.