Drug Integrating Amphiphilic Nano-Assemblies: 2. Spatiotemporal Distribution within Inflammation Sites

The need for chronic systemic immunosuppression, which is associated with unavoidable side-effects, greatly limits the applicability of allogeneic cell transplantation for regenerative medicine applications including pancreatic islet cell transplantation to restore insulin production in type 1 diabetes (T1D). Cell transplantation in confined sites enables the localized delivery of anti-inflammatory and immunomodulatory drugs to prevent graft loss by innate and adaptive immunity, providing an opportunity to achieve local effects while minimizing unwanted systemic side effects. Nanoparticles can provide the means to achieve the needed localized and sustained drug delivery either by graft targeting or co-implantation. Here, we evaluated the potential of our versatile platform of drug-integrating amphiphilic nanomaterial assemblies (DIANAs) for targeted drug delivery to an inflamed site model relevant for islet transplantation. We tested either passive targeting of intravenous administered spherical nanomicelles (nMIC; 20-25 nm diameter) or co-implantation of elongated nanofibrils (nFIB; 5 nm diameter and >1 μm length). To assess the ability of nMIC and nFIB to target an inflamed graft site, we used a lipophilic fluorescent cargo (DiD and DiR) and evaluated the in vivo biodistribution and cellular uptake in the graft site and other organs, including draining and non-draining lymph nodes, after systemic administration (nMIC) and/or graft co-transplantation (nFIB) in mice. Localized inflammation was generated either by using an LPS injection or by using biomaterial-coated islet-like bead implantation in the subcutaneous site. A cell transplant inflammation model was used as well to test nMIC- and nFIB-targeted biodistribution. We found that nMIC can reach the inflamed site after systemic administration, while nFIB remains localized for several days after co-implantation. We confirmed that DIANAs are taken up by different immune cell populations responsible for graft inflammation. Therefore, DIANA is a useful approach for targeted and/or localized delivery of immunomodulatory drugs to decrease innate and adaptive immune responses that cause graft loss after transplantation of therapeutic cells.

Efficient Production of Self-Assembled Bioconjugate Nanovaccines against Klebsiella pneumoniae O2 Serotype in Engineered Escherichia coli

Nanoparticles (NPs) have been surfacing as a pivotal platform for vaccine development. In our previous work, we developed a cholera toxin B subunit (CTB)-based self-assembled nanoparticle (CNP) and produced highly promising bioconjugate nanovaccines by loading bacterial polysaccharide (OPS) in vivo. In particular, the Klebsiella pneumoniae O2 serotype vaccine showcased a potent immune response and protection against infection. However, extremely low yields limited its further application. In this study, we prepared an efficient Klebsiella pneumoniae bioconjugate nanovaccine in Escherichia coli with a very high yield. By modifying the 33rd glycine (G) in the CNP to aspartate (D), we were able to observe a dramatically increased expression of glycoprotein. Subsequently, through a series of mutations, we determined that G33D was essential to increasing production. In addition, this increase only occurred in engineered E. coli but not in the natural host K. pneumoniae strain 355 (Kp355) expressing OPSKpO2. Next, T-cell epitopes were fused at the end of the CNP(G33D), and animal experiments showed that fusion of the M51 peptide induced high antibody titers, consistent with the levels of the original nanovaccine, CNP-OPSKpO2. Hence, we provide an effective approach for the high-yield production of K. pneumoniae bioconjugate nanovaccines and guidance for uncovering glycosylation mechanisms and refining glycosylation systems.

Production of Promising Heat-Labile Enterotoxin (LT) B Subunit-Based Self-Assembled Bioconjugate Nanovaccines against Infectious Diseases

Nanoparticles (NPs) have been widely utilized in vaccine design. Although numerous NPs have been explored, NPs with adjuvant effects on their own have rarely been reported. We produce a promising self-assembled NP by integrating the pentameric Escherichia coli heat-labile enterotoxin B subunit (LTB) (studied as a vaccine adjuvant) with a trimer-forming peptide. This fusion protein can self-assemble into the NP during expression, and polysaccharide antigens (OPS) are then loaded in vivo using glycosylation. We initially produced two Salmonella paratyphi A conjugate nanovaccines using two LTB subfamilies (LTIB and LTIIbB). After confirming their biosafety in mice, the data showed that both nanovaccines (NP(LTIB)-OPSSPA and NP(LTIIbB)-OPSSPA) elicited strong polysaccharide-specific antibody responses, and NP(LTIB)-OPS resulted in better protection. Furthermore, polysaccharides derived from Shigella or Klebsiella pneumoniae were loaded onto NP(LTIB) and NP(LTIIbB). The animal experimental results indicated that LTIB, as a pentamer module, exhibited excellent protection against lethal infections. This effect was also consistent with that of the reported cholera toxin B subunit (CTB) modular NP in all three models. For the first time, we prepared a novel promising self-assembled NP based on LTIB. In summary, these results indicated that the LTB-based nanocarriers have the potential for broad applications, further expanding the library of self-assembled nanocarriers.

Modular Self-Assembling Dendrimer Nanosystems for Magnetic Resonance and Multimodality Imaging of Tumors

Bioimaging is a powerful tool for diagnosing tumors but remains limited in terms of sensitivity and specificity. Nanotechnology-based imaging probes able to accommodate abundant imaging units with different imaging modalities are particularly promising for overcoming these limitations. In addition, the nanosized imaging agents can specifically increase the contrast of tumors by exploiting the enhanced permeability and retention effect. A proof-of-concept study is performed on pancreatic cancer to demonstrate the use of modular amphiphilic dendrimer-based nanoprobes for magnetic resonance (MR) imaging (MRI) or MR/near-infrared fluorescence (NIRF) multimodality imaging. Specifically, the self-assembly of an amphiphilic dendrimer bearing multiple Gd3+ units at its terminals, generates a nanomicellar agent exhibiting favorable relaxivity for MRI with a good safety profile. MRI reveals an up to two-fold higher contrast enhancement in tumors than in normal muscle. Encapsulating the NIRF dye within the core of the nanoprobe yields an MR/NIRF bimodal imaging agent for tumor detection that is efficient both for MRI, at Gd3+ concentrations 1/10 the standard clinical dose, and for NIRF imaging, allowing over two-fold stronger fluorescence intensities. These self-assembling dendrimer nanosystems thus constitute effective probes for MRI and MR/NIRF multimodality imaging, offering a promising nanotechnology platform for elaborating multimodality imaging probes in biomedical applications.

Self-Assembly of a Novel Pentapeptide into Hydrogelated Dendritic Architecture: Synthesis, Properties, Molecular Docking and Prospective Applications

Currently, ultrashort oligopeptides consisting of fewer than eight amino acids represent a cutting-edge frontier in materials science, particularly in the realm of hydrogel formation. By employing solid-phase synthesis with the Fmoc/tBu approach, a novel pentapeptide, FEYNF-NH2, was designed, inspired by a previously studied sequence chosen from hen egg-white lysozyme (FESNF-NH2). Qualitative peptide analysis was based on reverse-phase high performance liquid chromatography (RP-HPLC), while further purification was accomplished using solid-phase extraction (SPE). Exact molecular ion confirmation was achieved by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-ToF MS) using two different matrices (HCCA and DHB). Additionally, the molecular ion of interest was subjected to tandem mass spectrometry (MS/MS) employing collision-induced dissociation (CID) to confirm the synthesized peptide structure. A combination of research techniques, including Fourier-transform infrared spectroscopy (FTIR), fluorescence analysis, transmission electron microscopy, polarized light microscopy, and Congo red staining assay, were carefully employed to glean valuable insights into the self-assembly phenomena and gelation process of the modified FEYNF-NH2 peptide. Furthermore, molecular docking simulations were conducted to deepen our understanding of the mechanisms underlying the pentapeptide's supramolecular assembly formation and intermolecular interactions. Our study provides potential insights into amyloid research and proposes a novel peptide for advancements in materials science. In this regard, in silico studies were performed to explore the FEYNF peptide's ability to form polyplexes.

Engineering of Amphiphilic Erlotinib Analogue as Novel Nanomedicine for Non-Small Cell Lung Cancer Therapy

Purpose

Molecular targeted therapy is one of the most pivotal strategies in the treatment of non-small cell lung cancer, yet its curative effect is severely compromised by the poor aqueous solubility, low bioavailability and inadequate tumor accumulation of targeted agents. To enhance the efficacy of targeted agents, we demonstrate a novel self-assemble amphiphilic molecule based on erlotinib as an effective nanodrug for anti-cancer treatment.

Methods

An amphiphilic molecule composed of hydrophobic erlotinib and hydrophilic biotin block was synthesized and characterized by nuclear magnetic resonance (NMR) as well as high-resolution mass spectrometry (HRMS). Then, nanoassemblies of the amphiphilic molecules are formulated by using nanoprecipitation method. Subsequently, the size, morphology, cell uptake, the anticancer activity and in vivo distribution of the newly constructed erlotinib nanodrug were systematically assessed by some methods, including transmission electron microscopy (TEM), dynamic light-scattering (DLS), flow cytometry, in vivo imaging system etc.

Results

We developed a novel nanoformulation of erlotinib, which possesses a high drug loading of 45%. With the features of well-defined structure and small size, the obtained nanodrug could be effectively accumulated in tumor sites and rapidly internalized by cancer cells. Finally, the erlotinib-based nanoformulation showed considerably better anticancer activity compared to free erlotinib both in vitro and in vivo. Moreover, the nanodrug displayed great tolerability.

Conclusion

Combining the advantageous features of both nanotechnology and self-assemble, this novel erlotinib nanomedicine constitutes a promising therapeutic candidate for cancer treatment. This study also underlines the potential use of amphiphilic molecule for improving drug efficacy as well as reducing drug toxicity, which could become a general strategy for the preparation of nanodrugs of active agents.

Deep Learning Empowers the Discovery of Self-Assembling Peptides with Over 10 Trillion Sequences

Self-assembling of peptides is essential for a variety of biological and medical applications. However, it is challenging to investigate the self-assembling properties of peptides within the complete sequence space due to the enormous sequence quantities. Here, it is demonstrated that a transformer-based deep learning model is effective in predicting the aggregation propensity (AP) of peptide systems, even for decapeptide and mixed-pentapeptide systems with over 10 trillion sequence quantities. Based on the predicted AP values, not only the aggregation laws for designing self-assembling peptides are derived, but the transferability relation among the APs of pentapeptides, decapeptides, and mixed pentapeptides is also revealed, leading to discoveries of self-assembling peptides by concatenating or mixing, as consolidated by experiments. This deep learning approach enables speedy, accurate, and thorough search and design of self-assembling peptides within the complete sequence space of oligopeptides, advancing peptide science by inspiring new biological and medical applications.

Self-Calibrating Lanthanide Infinite Coordination Polymer Constructs Fluorescent Probes: A Sensitive Approach for Early Diagnosis of Hepatocellular Carcinoma and Environmental Analysis

The development of a self-calibrating ratio fluorescence probe without the need for additional substrates is a major advancement in biosensing. In this study, at room temperature, a self-calibrating infinite coordination polymer (SSA-Tb-ATP ICPs) has been proposed by self-assembling adenosine triphosphate (ATP) with 5-sulfosalicylic acid (SSA) and Tb3+. Due to the antenna effect, SSA-Tb-ATP ICPs exhibited strong green fluorescence emission of Tb3+ (at 547 nm) and blue fluorescence emission of SSA (at 407 nm). This material offers several advantages over existing detection methods, including simplicity of synthesis and exceptional sensitivity. Our self-calibrating SSA-Tb-ATP ICPs demonstrated excellent performance in detecting alkaline phosphatase (ALP) and phosphate (Pi) in both serum and environmental samples with detection limits of 0.076 U/L and 0.025 μM, respectively. Moreover, we successfully employed the SSA-Tb-ATP ICPs to perform cellular imaging of ALP in both hepatocellular carcinoma cells (HepG2) and normal liver cells (LO2), representing a significant advancement in ALP detection and imaging. The simplicity of the synthesis and high sensitivity make this probe a promising tool for early diagnosis of hepatocellular carcinoma in clinical settings and environment analysis.

Merging Solid-Phase Peptide Synthesis and Automated Glycan Assembly to Prepare Lipid-Peptide-Glycan Chimeras

Biomaterials with improved biological features can be obtained by conjugating glycans to nanostructured peptides. Creating peptide-glycan chimeras requires superb chemoselectivity. We expedite access to such chimeras by merging peptide and glycan solid-phase syntheses employing a bifunctional monosaccharide. The concept was explored in the context of the on-resin generation of a model α(1→6)tetramannoside linked to peptides, lipids, steroids, and adamantane. Chimeras containing a β(1→6)tetraglucoside and self-assembling peptides such as FF, FFKLVFF, and the amphiphile palmitoyl-VVVAAAKKK were prepared in a fully automated manner. The robust synthetic protocol requires a single purification step to obtain overall yields of about 20 %. The β(1→6)tetraglucoside FFKLVFF chimera produces micelles rather than nanofibers formed by the peptide alone as judged by microscopy and circular dichroism. The peptide amphiphile-glycan chimera forms a disperse fiber network, creating opportunities for new glycan-based nanomaterials.

Probing the Biosafety of Implantable Artificial Secretory Granules for the Sustained Release of Bioactive Proteins

Among bio-inspired protein materials, secretory protein microparticles are of clinical interest as self-contained, slow protein delivery platforms that mimic secretory granules of the human endocrine system, in which the protein is both the drug and the scaffold. Upon subcutaneous injection, their progressive disintegration results in the sustained release of the building block polypeptides, which reach the bloodstream for systemic distribution and subsequent biological effects. Such entities are easily fabricated in vitro by Zn-assisted cross-molecular coordination of histidine residues. Using cationic Zn for the assembly of selected pure protein species and in the absence of any heterologous holding material, these granules are expected to be nontoxic and therefore adequate for different clinical uses. However, such presumed biosafety has not been so far confirmed and the potential protein dosage threshold not probed yet. By selecting the receptor binding domain (RBD) from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein as a model protein and using a mouse lab model, we have explored the toxicity of RBD-made secretory granules at increasing doses up to ∼100 mg/kg of animal weight. By monitoring body weight and biochemical blood markers and through the histological scrutiny of main tissues and organs, we have not observed systemic toxicity. Otherwise, the bioavailability of the material was demonstrated by the induction of specific antibody responses. The presented data confirm the intrinsic biosafety of artificial secretory granules made by recombinant proteins and prompt their further clinical development as self-contained and dynamic protein reservoirs.

Voltammetric Sensor for Doxorubicin Determination Based on Self-Assembled DNA-Polyphenothiazine Composite

A novel voltammetric sensor based on a self-assembled composite formed by native DNA and electropolymerized N-phenyl-3-(phenylimino)-3H-phenothiazin-7-amine has been developed and applied for sensitive determination of doxorubicin, an anthracycline drug applied for cancer therapy. For this purpose, a monomeric phenothiazine derivative has been deposited on the glassy carbon electrode from the 0.4 M H2SO4-acetone mixture (1:1 v/v) by multiple potential cycling. The DNA aliquot was either on the electrode modified with electropolymerized film or added to the reaction medium prior to electropolymerization. The DNA entrapment and its influence on the redox behavior of the underlying layer were studied by scanning electron microscopy and electrochemical impedance spectroscopy. The DNA-doxorubicin interactions affected the charge distribution in the surface layer and, hence, altered the redox equilibrium of the polyphenothiazine coating. The voltametric signal was successfully applied for the determination of doxorubicin in the concentration range from 10 pM to 0.2 mM (limit of detection 5 pM). The DNA sensor was tested on spiked artificial plasma samples and two commercial medications (recovery of 90-95%). After further testing on real clinical samples, the electrochemical DNA sensor developed can find application in monitoring drug release and screening new antitumor drugs able to intercalate DNA.

Linkers in fragment-based drug design: an overview of the literature

INTRODUCTION

In fragment-based drug design, fragment linking is a popular strategy where two fragments binding to different sub-pockets of a target are linked together. This attractive method remains challenging especially due to the design of ideal linkers.

AREAS COVERED

The authors review the types of linkers and chemical reactions commonly used to the synthesis of linkers, including those utilized in protein-templated fragment self-assembly, where fragments are directly linked in the presence of the protein. Finally, they detail computational workflows and software including generative models that have been developed for fragment linking.

EXPERT OPINION

The authors believe that fragment linking offers key advantages for compound design, particularly for the design of bivalent inhibitors linking two distinct pockets of the same or different subunits. On the other hand, more studies are needed to increase the potential of protein-templated approaches in FBDD. Important computational tools such as structure-based de novo software are emerging to select suitable linkers. Fragment linking will undoubtedly benefit from developments in computational approaches and machine learning models.

Synthesis and Characterization of Novel Amphiphilic N-Benzyl 1,4-Dihydropyridine Derivatives-Evaluation of Lipid Monolayer and Self-Assembling Properties

Liposomes and other nanoparticles have been widely studied as innovative nanomaterials because of their unique properties. Pyridinium salts, on the basis of 1,4-dihydropyridine (1,4-DHP) core, have gained significant attention due to their self-assembling properties and DNA delivery activity. This study aimed to synthesize and characterize original N-benzyl substituted 1,4-dihydropyridines and evaluate the influence on structure modifications on compound physicochemical and self-assembling properties. Studies of monolayers composed of 1,4-DHP amphiphiles revealed that the mean molecular areas values were dependent on the compound structure. Therefore, the introduction of N-benzyl substituent to the 1,4-DHP ring enlarged the mean molecular area by almost half. All nanoparticle samples obtained by ethanol injection method possessed positive surface charge and average diameter of 395-2570 nm. The structure of the cationic head-group affects the size of the formed nanoparticles. The diameter of lipoplexes formed by 1,4-DHP amphiphiles and mRNA at nitrogen/phosphate (N/P) charge ratios of 1, 2, and 5 were in the range of 139-2959 nm and were related to the structure of compound and N/P charge ratio. The preliminary results indicated that more prospective combination are the lipoplexes formed by pyridinium moieties containing N-unsubstituted 1,4-DHP amphiphile 1 and pyridinium or substituted pyridinium moieties containing N-benzyl 1,4-DHP amphiphiles 5a-c at N/P charge ratio of 5, which would be good candidates for potential application in gene therapy.

Recent Advances in Antimicrobial Peptide Hydrogels

Advances in the number and type of available biomaterials have improved medical devices such as catheters, stents, pacemakers, prosthetic joints, and orthopedic devices. The introduction of a foreign material into the body comes with a risk of microbial colonization and subsequent infection. Infections of surgically implanted devices often lead to device failure, which leads to increased patient morbidity and mortality. The overuse and improper use of antimicrobials has led to an alarming rise and spread of drug-resistant infections. To overcome the problem of drug-resistant infections, novel antimicrobial biomaterials are increasingly being researched and developed. Hydrogels are a class of 3D biomaterials consisting of a hydrated polymer network with tunable functionality. As hydrogels are customizable, many different antimicrobial agents, such as inorganic molecules, metals, and antibiotics have been incorporated or tethered to them. Due to the increased prevalence of antibiotic resistance, antimicrobial peptides (AMPs) are being increasingly explored as alternative agents. AMP-tethered hydrogels are being increasingly examined for antimicrobial properties and practical applications, such as wound-healing. Here, we provide a recent update, from the last 5 years of innovations and discoveries made in the development of photopolymerizable, self-assembling, and AMP-releasing hydrogels.

Study of Innovative GO/PBI Composites as Possible Proton Conducting Membranes for Electrochemical Devices

The appeal of combining polybenzimidazole (PBI) and graphene oxide (GO) for the manufacturing of membranes is increasingly growing, due to their versatility. Nevertheless, GO has always been used only as a filler in the PBI matrix. In such context, this work proposes the design of a simple, safe, and reproducible procedure to prepare self-assembling GO/PBI composite membranes characterized by GO-to-PBI (X:Y) mass ratios of 1:3, 1:2, 1:1, 2:1, and 3:1. SEM and XRD suggested a homogenous reciprocal dispersion of GO and PBI, which established an alternated stacked structure by mutual π-π interactions among the benzimidazole rings of PBI and the aromatic domains of GO. TGA indicated a remarkable thermal stability of the composites. From mechanical tests, improved tensile strengths but worsened maximum strains were observed with respect to pure PBI. The preliminary evaluation of the suitability of the GO/PBI X:Y composites as proton exchange membranes was executed via IEC determination and EIS. GO/PBI 2:1 (IEC: 0.42 meq g^-1; proton conductivity at 100 °C: 0.0464 S cm^-1) and GO/PBI 3:1 (IEC: 0.80 meq g^-1; proton conductivity at 100 °C: 0.0451 S cm^-1) provided equivalent or superior performances with respect to similar PBI-based state-of-the-art materials.

Rational Design of a Self-Assembling High Performance Organic Nanofluorophore for Intraoperative NIR-II Image-Guided Tumor Resection of Oral Cancer

The first line of treatment for most solid tumors is surgical resection of the primary tumor with adequate negative margins. Incomplete tumor resections with positive margins account for over 75% of local recurrences and the development of distant metastases. In cases of oral cavity squamous cell carcinoma (OSCC), the rate of successful tumor removal with adequate margins is just 50-75%. Advanced real-time imaging methods that improve the detection of tumor margins can help improve success rates,overall safety, and reduce the cost. Fluorescence imaging in the second near-infrared (NIR-II) window has the potential to revolutionize the field due to its high spatial resolution, low background signal, and deep tissue penetration properties, but NIR-II dyes with adequate in vivo performance and safety profiles are scarce. A novel NIR-II fluorophore, XW-03-66, with a fluorescence quantum yield (QY) of 6.0% in aqueous media is reported. XW-03-66 self-assembles into nanoparticles (≈80 nm) and has a systemic circulation half-life (t_1/2 ) of 11.3 h. In mouse models of human papillomavirus (HPV)+ and HPV- OSCC, XW-03-66 outperformed indocyanine green (ICG), a clinically available NIR dye, and enabled intraoperative NIR-II image-guided resection of the tumor and adjacent draining lymph node with negative margins. In vitro and in vivo toxicity assessments revealed minimal safety concerns for in vivo applications.

Reduced Graphene Oxide/Waste-Derived TiO2 Composite Membranes: Preliminary Study of a New Material for Hybrid Wastewater Treatment

This work reports the preliminary results of the development of composite self-assembling membranes obtained by the combination of reduced graphene oxide (rGO) with commercial Degussa P25 titanium dioxide (TiO₂). The purpose is to demonstrate the possibility of combining, in the same self-standing material, the capability to treat wastewater containing both inorganic and organic pollutants by exploiting the established ability of rGO to capture metal ions together with that of TiO₂ to degrade organic substances. Moreover, this study also investigates the potential photocatalytic properties of tionite (TIO), to demonstrate the feasibility of replacing commercial TiO₂ with such waste-derived TiO₂-containing material, fulfilling a circular economy approach. Thus, rGO-TiO₂ and rGO-TIO composite membranes, 1:1 by weight, were prepared and characterized by SEM-EDX, XRD, thermogravimetry, as well as by Raman and UV-Vis spectroscopies to verify the effective and homogeneous integration of the two components. Then, they were tested towards 3-mg L^-1 aqueous synthetic solutions of Fe³⁺ and Cu²⁺ ions to evaluate their metal adsorption ability, with values of the order of 0.1-0.2 mmol g_membrane^-1, comparable or even slightly higher than those of pristine rGO. Finally, the ability of the composites to degrade a common organic pesticide, i.e., Imidacloprid^®, was assessed in preliminary photocatalysis experiments, in which maximum degradation efficiencies of 25% (after 3 h) for rGO-TiO₂ and of 21% (after 1 h) for rGO-TIO were found. The result of tionite-containing membranes is particularly promising and worthy of further investigation, given that the anatase content of tionite is roughly 1/6 of the one in commercial TiO₂.

Inherent Capability of Self-Assembling Nanostructures in Specific Proteasome Activation for Cancer Cell Pyroptosis

Understanding the direct interaction of nanostructures per se with biological systems is important for biomedical applications. However, whether nanostructures regulate biological systems by targeting specific cellular proteins remains largely unknown. In the present work, self-assembling nanomicelles are constructed using small-molecule oleanolic acid (OA) as a molecular template. Unexpectedly, without modifications by functional ligands, OA nanomicelles significantly activate cellular proteasome function by directly binding to 20S proteasome subunit alpha 6 (PSMA6). Mechanism study reveals that OA nanomicelles interact with PSMA6 to dynamically modulate its N-terminal domain conformation change, thereby controlling the entry of proteins into 20S proteasome. Subsequently, OA nanomicelles accelerate the degradation of several crucial proteins, thus potently driving cancer cell pyroptosis. For translational medicine, OA nanomicelles exhibit a significant anticancer potential in tumor-bearing mouse models and stimulate immune cell infiltration. Collectively, this proof-of-concept study advances the mechanical understanding of nanostructure-guided biological effects via their inherent capacity to activate proteasome.

Intra- and Intermolecular Cooperativity in the Catalytic Activity of Phosphodiester Cleavage by Self-Assembled Systems Based on Guanidinylated Calix[4]arenes

The calix[4]arene scaffold, blocked in the cone conformation through alkylation with long alkyl chains, and decorated at the upper rim with four guanidine or arginine units, effectively catalyzes the cleavage of the phosphodiester bond of DNA and RNA model compounds in water. An exhaustive kinetic investigation unequivocally points to the existence of spontaneous aggregation phenomena, driven by hydrophobic effect, occurring at different critical concentrations that depend on the identity of the compound. A pronounced superiority of the assembled structures compared with the monomers in solution was observed. Moreover, the catalytically active units, clustered on the macrocyclic tetrafunctional scaffold, were proved to efficiently cooperate in the catalytic mechanism and result in improved reaction rates compared to those of the monofunctional model compounds. The kinetic analysis is also integrated and corroborated with further experiments based on fluorescence spectroscopy and light scattering. The advantage of the supramolecular assemblies based on tetrafunctional calixarenes leads to believe that the active units can cooperate not only intramolecularly but also intermolecularly. The molecules in the aggregates can probably mold, flex and rearrange but, at the same time, keep an ordered structure that favors phosphodiester bond cleavage. This dynamic preorganization can allow the catalytic units to reach a better fitting with the substrates and perform a superior catalytic activity.

[Chemical reaction mechanism of decoction of traditional Chinese medicines: a review]

Complicated chemical reactions occur in the decoction of traditional Chinese medicines(TCMs) which features complex components, influencing the safety, efficacy, and quality controllability of TCMs. Therefore, it is particularly important to clarify the chemical reaction mechanism of TCMs in the decoction. This study summarized eight typical chemical reactions in the decoction of TCMs, such as substitution reaction, redox reaction, isomerization/stereoselective reaction, complexation, and supramolecular reaction. With the "toxicity attenuation and efficiency enhancement" of aconitines and other examples, this study reviewed the reactions in decoction of TCMs, which was expected to clarify the variation mechanisms of key chemical components in this process and to help guide medicine preparation and safe and rational use of medicine in clinical settings. The current main research methods for chemical reaction mechanisms of decoction of TCMs were also summed up and compared. The novel real-time analysis device of decoction system for TCMs was found to be efficient and simple without the pre-treatment of samples. This device provides a promising solution, which has great potential in quantity evaluation and control of TCMs. Moreover, it is expected to become a foundational and exemplary research tool, which can advance the research in this field.

A Diphenylalanine Based Pentapeptide with Fibrillating Self-Assembling Properties

Peptides and their related compounds can self-assemble into diverse nanostructures of different shapes and sizes in response to various stimuli such as pH, temperature or ionic strength. Here we report the synthesis and characterization of a lysozyme derived pentapeptide and its ability to build well-defined fibrillar structures. Lysozyme FESNF peptide fragment was synthesized by solid phase peptide synthesis using the Fmoc/t-Bu strategy, purified by analytical high-performance liquid chromatography (HPLC) and its molecular weight was confirmed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Spectroscopic features of this pentapeptide were investigated by UV-visible spectroscopy and fluorimetry showing the pattern of marginal phenylalanine residues within the peptide sequence. Self-assembling properties were determined using atomic force microscopy (AFM), aggregation index and thioflavin T assay (ThT). FESNF generating fibrillar structures observed by AFM and aggregation propensity were primarily influenced by pH conditions. Moreover, the experimental data were confirmed by molecular dynamics simulation studies. The obtained fibrils will be used next to explore their potential to act as support material for medical and cosmetic application.

Achieving High Thermal Conductivity and Satisfactory Insulating Properties of Elastomer Composites by Self-Assembling BN@GO Hybrids

With increasing heat accumulation in advanced modern electronic devices, dielectric materials with high thermal conductivity (λ) and excellent electrical insulation have attracted extensive attention in recent years. Inspired by mussel, hexagonal boron nitride (hBN) and graphene oxide (GO) are assembled to construct mhBN@GO hybrids with the assistance of poly(catechol-polyamine). Then, mhBN@GO hybrids are dispersed in carboxy nitrile rubber (XNBR) latex via emulsion coprecipitation to form elastomer composites with a high λ and satisfactory insulating properties. Thanks to the uniform dispersion of mhBN@GO hybrids, the continuous heat conduction pathways exert a significant effect on enhancing the λ and decreasing the interface thermal resistance of XNBR composites. In particular, the λ value of 30 vol% mhBN@GO/XNBR composite reaches 0.4348 W/(m·K), which is 2.7 times that of the neat XNBR (0.1623 W/(m·K)). Meanwhile, the insulating hBN platelets hinder the electron transfer between adjacent GO sheets, leading to satisfactory electrical insulation in XNBR composites, whose AC conductivity is as low as 10^-10 S/cm below 100 Hz. This strategy opens up new prospects in the assembly of ceramic and carbonaceous fillers to prepare dielectric elastomer composites with high λ and satisfactory electrical insulation, making them promising for modern electrical systems.

Suitability of high-molecular-weight tissue-derived elastin polypeptides and their particles as cosmetic biomaterials

We aimed to determine the coacervation properties of high-molecular-weight (HMW) tissue-derived elastin (TDE) and to examine the potential use of TDE particles as a cosmetic biomaterial. TDE solutions were filtered and divided into three fractions (1-3) according to the molecular weight of the elastin. The turbidity of fraction 2, which contained a large portion (58%) of HMW elastin polypeptides (>100 kDa), was measured under several pH values (3.0-11.0) and NaCl concentrations (0-1000 mM) to examine its coacervation ability. HMW TDE exhibited coacervation under the physiological conditions (temperature, pH, and NaCl concentration) of the skin surface. We performed inclusion and release experiments using three model chemicals with different molecular weights and measured the size and zeta potential of the fraction 3 particles to investigate the suitability of HMW elastin polypeptides. Fraction 3, which contained a larger portion (64%) of HMW elastin polypeptides, displayed a strong coacervation property at a phase transition temperature of 19.8 ± 0.1°C. The inclusion ratio of the model chemical Biebrich Scarlet (BS) with a molecular weight of <600 was approximately 92.1 ± 0.7%. The release profiles of BS from the particles linearly increased and reached a plateau after 15 days. Moreover, the average size of the particles with BS was 474.2 ± 24.6 nm. The low-molecular-weight (LMW) elastin peptides have moisturizing and whitening functions for the skin. We concluded that TDE, as a mixture of HMW polypeptides and LMW peptides, can potentially serve as a multifunctional and effective cosmetic biomaterial.

Anticorrosion Superhydrophobic Surfaces on AA6082 Aluminum Alloy by HF/HCl Texturing and Self-Assembling of Silane Monolayer

In this paper, the tailoring of superhydrophobic surfaces on AA6082 aluminum alloy by chemical etching in an HF/HCl solution, followed by silane self-assembling, was applied for enhanced corrosion protection in the marine field. In particular, different etching times were considered in order to optimize the treatment effect. The results indicate that all the prepared surfaces, after silanization, were characterized by superhydrophobic behavior with a contact angle higher than 150°. The contact and sliding angles strongly depend on the surface morphology at varying etching times. The optimum was observed with an etching time of 20 s, where a microscale coral-like structure coupled with a homogeneous and ordered pixel-like nanostructure was obtained on the aluminum surface showing a Cassie-Baxter superhydrophobic behavior with a water contact angle of 180° and a sliding angle equal to 0°. All superhydrophobic surfaces achieved an enhanced corrosion protection efficiency and impedance modulus up to two orders of magnitude higher than the as-received AA6082 in simulated seawater.

The Diphtheria Toxin Translocation Domain Impairs Receptor Selectivity in Cancer Cell-Targeted Protein Nanoparticles

Protein-based materials intended as nanostructured drugs or drug carriers are progressively gaining interest in nanomedicine, since their structure, assembly and cellular interactivity can be tailored by recruiting functional domains. The main bottleneck in the development of deliverable protein materials is the lysosomal degradation that follows endosome maturation. This is especially disappointing in the case of receptor-targeted protein constructs, which, while being highly promising and in demand in precision medicines, enter cells via endosomal/lysosomal routes. In the search for suitable protein agents that might promote endosome escape, we have explored the translocation domain (TD) of the diphtheria toxin as a functional domain in CXCR4-targeted oligomeric nanoparticles designed for cancer therapies. The pharmacological interest of such protein materials could be largely enhanced by improving their proteolytic stability. The incorporation of TD into the building blocks enhances the amount of the material detected inside of exposed CXCR4⁺ cells up to around 25-fold, in absence of cytotoxicity. This rise cannot be accounted for by endosomal escape, since the lysosomal degradation of the new construct decreases only moderately. On the other hand, a significant loss in the specificity of the CXCR4-dependent cellular penetration indicates the unexpected role of the toxin segment as a cell-penetrating peptide in a dose-dependent and receptor-independent fashion. These data reveal that the diphtheria toxin TD displayed on receptor-targeted oligomeric nanoparticles partially abolishes the exquisite receptor specificity of the parental material and it induces nonspecific internalization in mammalian cells.

Computer-Aided Design of Lasso-like Self-Assembling Anticancer Peptides with Multiple Functions for Targeted Self-Delivery and Cancer Treatments

Anticancer peptides are promising drug candidates for cancer treatment, but the short circulation time and low delivery efficiency limit their clinical applications. Herein, we designed several lasso-like self-assembling anticancer peptides (LASAPs) integrated with multiple functions by a computer-aided approach. Among these LASAPs, LASAP1 (CRGDKGPDCGKAFRRFLGALFKALSHLL, 1-9 disulfide bond) was determined to be superior to the others because it can self-assemble into homogeneous nanoparticles and exhibits improved stability in serum. Thus, LASAP1 was chosen for proving the design idea. LASAP1 can self-assemble into nanoparticles displaying iRGD on the surface because of its amphiphilic structure and accumulate to the tumor site after injection because of the EPR effect and iRGD targeting to αVβ3 integrin. The nanoparticles could disassemble in the acidic microenvironment of the solid tumor, and cleaved by the overexpressed hK2, which was secreted by prostate tumor cells, to release the effector peptide PTP-7b (FLGALFKALSHLL), which was further activated by the acidic pH. Therefore, LASAP1 could target the orthotopic prostate tumor in the model mice after intraperitoneal injection and specifically inhibit tumor growth, with low systematic toxicity. Combining the multiple targeting functions, LASAP1 represents a promising design of self-delivery of peptide drugs for targeted cancer treatments.

Formation of Gold Nanoparticle Self-Assembling Films in Various Polymer Matrices for SERS Substrates

Surface-enhanced Raman spectroscopy (SERS) is regarded as a versatile tool for studying the composition and structure of matter. This work has studied the preparation of a SERS substrate based on a self-assembling plasmonic nanoparticle film (SPF) in a polymer matrix. Several synthesis parameters for the SPF are investigated, including the size of the particles making up the film and the concentration and type of the self-assembling agent. The result of testing systems with different characteristics is discussed using a model substance (pseudoisocyanin iodide). These models can be useful in the study of biology and chemistry. Research results contain the optimal parameters for SPF synthesis, maximizing the SERS signal. The optimal procedure for SPF assembly is determined and used for the synthesis of composite SPFs within different polymer matrices. SPF in a polymer matrix is necessary for the routine use of the SERS substrate for various types of analytes, including solid samples or those sensitive to contamination. Polystyrene, polyvinyl alcohol (PVA), and polyethylene are investigated to obtain a polymer matrix for SPF, and various methods of incorporating SPF into a polymer matrix are being explored. It is found that films with the best signal enhancement and reproducibility were obtained in polystyrene. The minimum detectable concentration for the SERS substrate obtained is equal to 10⁻¹⁰ M. We prepared a SERS substrate with an analytical enhancement factor of 2.7 × 10⁴, allowing an increase in the detection sensitivity of analyte solutions of five orders of magnitude.

The in vivo fate of polymeric micelles

This review aims to provide a systemic analysis of the in vivo, as well as subcellular, fate of polymeric micelles (PMs), starting from the entry of PMs into the body. Few PMs are able to cross the biological barriers intact and reach the circulation. In the blood, PMs demonstrate fairly good stability mainly owing to formation of protein corona despite controversial results reported by different groups. Although the exterior hydrophilic shells render PMs "long-circulating", the biodistribution of PMs into the mononuclear phagocyte systems (MPS) is dominant as compared with non-MPS organs and tissues. Evidence emerges to support that the copolymer poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) is first broken down into pieces of PEG and PLA and then remnants to be eliminated from the body finally. At the cellular level, PMs tend to be internalized via endocytosis due to their particulate nature and disassembled and degraded within the cell. Recent findings on the effect of particle size, surface characteristics and shape are also reviewed. It is envisaged that unraveling the in vivo and subcellular fate sheds light on the performing mechanisms and gears up the clinical translation of PMs.

Multicomponent Hydrogel Matrices of Fmoc-FF and Cationic Peptides for Application in Tissue Engineering

In the last years, peptide based hydrogels are being increasingly used as suitable matrices for biomedical and pharmaceutical applications, including drug delivery and tissue engineering. Recently, we decrived the synthesis and the gelation properties of a small library of cationic peptides, containing a Lys residue at the C-teminus and derivatized with a Fmoc group or with the Fmoc-diphenylalanine (FmocFF) at the N-terminus. Here, we demonstrate that the combination of these peptides with the well known hydrogelator FmocFF, in different weight/weight ratios, allows the achievement of seven novel self-sorted hydrogels, which share similar peptide organization of their supramolecular matrix. Rheological and relaxometric characterization highlighted a different mechanical rigidity and water mobility in the gels as demostrated by the storage modulus values (200 Pa<G'<35000 Pa) and by relaxometry, respectively. In vitro studied demonstrated that most of the tested mixed hydrogels do not disturb significantly the cell viability (>95%) over 72h of treatment. Moreover, in virtue to its capability to strongly favour adhesion, spreading and duplication of 3T3-L1 cells, one of the tested hydrogel may be eligible as sinthetic extracellular matrix. This article is protected by copyright. All rights reserved.

Designing Self-Assembling Chimeric Peptide Nanoparticles with High Stability for Combating Piglet Bacterial Infections

As a novel type of antibiotic alternative, peptide-based antibacterial drug shows potential application prospects attributable to their unique mechanism for lysing the membrane of pathogenic bacteria. However, peptide-based antibacterial drugs suffer from a series of problems, most notably their immature stability, which seriously hinders their application. In this study, self-assembling chimeric peptide nanoparticles (which offer excellent stability in the presence of proteases and salts) are constructed and applied to the treatment of bacterial infections. In vitro studies are used to demonstrate that peptide nanoparticles NPs1 and NPs2 offer broad-spectrum antibacterial activity and desirable biocompatibility, and they retain their antibacterial ability in physiological salt environments. Peptide nanoparticles NPs1 and NPs2 can resist degradation under high concentrations of proteases. In vivo studies illustrate that the toxicity caused by peptide nanoparticles NPs1 and NPs2 is negligible, and these nanoparticles can alleviate systemic bacterial infections in mice and piglets. The membrane permeation mechanism and interference with the cell cycle differ from that of antibiotics and mean that the nanoparticles are at a lower risk of inducing drug resistance. Collectively, these advances may accelerate the development of peptide-based antibacterial nanomaterials and can be applied to the construction of supramolecular nanomaterials.

Screening of Self-Assembling of Collagen IV Fragments into Stable Structures Potentially Useful in Regenerative Medicine

The aim of the research was to check whether it is possible to use fragments of type IV collagen to obtain, as a result of self-assembling, stable spatial structures that could be used to prepare new materials useful in regenerative medicine. Collagen IV fragments were obtained by using DMT/NMM/TosO- as a coupling reagent. The ability to self-organize and form stable spatial structures was tested by the CD method and microscopic techniques. Biological studies covered: resazurin assay (cytotoxicity assessment) on BJ, BJ-5TA and C2C12 cell lines; an alkaline version of the comet assay (genotoxicity), Biolegend Legendplex human inflammation panel 1 assay (SC cell lines, assessment of the inflammation activity) and MTT test to determine the cytotoxicity of the porous materials based on collagen IV fragments. It was found that out of the pool of 37 fragments (peptides 1-33 and 2.1-2.4) reconstructing the outer sphere of collagen IV, nine fragments (peptides: 2, 4, 5, 6, 14, 15, 25, 26 and 30), as a result of self-assembling, form structures mimicking the structure of the triple helix of native collagens. The stability of spatial structures formed as a result of self-organization at temperatures of 4 °C, 20 °C, and 40 °C was found. The application of the MST method allowed us to determine the Kd of binding of selected fragments of collagen IV to ITGα1β1. The stability of the spatial structures of selected peptides made it possible to obtain porous materials based on their equimolar mixture. The formation of the porous materials was found for cross-linked structures and the material stabilized only by weak interactions. All tested peptides are non-cytotoxic against all tested cell lines. Selected peptides also showed no genotoxicity and no induction of immune system responses. Research on the use of porous materials based on fragments of type IV collagen, able to form stable spatial structures as scaffolds useful in regenerative medicine, will be continued.

Self-assembling human skeletal organoids for disease modeling and drug testing

Skeletal conditions represent a considerable challenge to health systems globally. Barriers to effective therapeutic development include a lack of accurate preclinical tissue and disease models. Most recently, work was attempted to present a novel whole organ approach to modeling human bone and cartilage tissues. These self-assembling skeletal organoids mimic the cellular milieu and extracellular organization present in native tissues. Bone organoids demonstrated osteogenesis and micro vessel formation, and cartilage organoids showed evidence of cartilage development and maturation. Skeletal organoids derived from both bone and cartilage tissues yielded spontaneous polarization of their cartilaginous and bone components. Using these hybrid skeletal organoids, we successfully generated "mini joint" cultures, which we used to model inflammatory disease and test Adenosine (A_2A ) receptor agonists as a therapeutic agent. The work and respective results indicated that skeletal organoids can be an effective biological model for tissue development and disease as well as to test therapeutic agents.

Facile synthesis of near-infrared bodipy by donor engineering for in vivo tumor targeted dual-modal imaging

Bodipy is one of the most popular dyes for bioimaging, however, a complicated synthetic protocol is needed to create and isolate ideal near-infrared (NIR) emissive Bodipy derivatives for optical bioimaging. It is noticed that the donor species impact the wavelength when the π-conjugation system of green light emissive Bodipy is elongated via a one-step reaction. Herein, several Bodipy dyes bearing different common donors are synthesized. Their optical properties confirm that both absorption and emission peaks of the synthesized Bodipy could be tuned to NIR wavelength by using stronger donors via a facile reaction. The synthesized monocarboxyl Bodipy could conjugate with aminated PEG to yield an amphiphilic polymer, which further self-assembles into a NIR nanoparticle (NP). The NIR NP exhibits preferential tumor accumulation via the enhanced permeation and retention (EPR) effect, making it useful for tumor diagnosis by both fluorescence imaging and photoacoustic tomography.

The Introduction of a Cysteine Residue Modulates The Mechanical Properties of Aromatic-Based Solid Aggregates and Self-Supporting Hydrogels

Peptide-based hydrogels, originated by multiscale self-assembling phenomenon, have been proposed as multivalent tools in different technological areas. Structural studies and molecular dynamics simulations pointed out the capability of completely aromatic peptides to gelificate if hydrophilic and hydrophobic forces are opportunely balanced. Here, the effect produced by the introduction of a Cys residue in the heteroaromatic sequence of (FY)3 and in its PEGylated variant was evaluated. The physicochemical characterization indicates that both FYFCFYF and PEG8-FYFCFYF are able to self-assemble in supramolecular nanostructures whose basic cross-β motif resembles the one detected in the ancestor (FY)3 assemblies. However, gelification occurs only for FYFCFYF at a concentration of 1.5 wt%. After cross-linking of cysteine residues, the hydrogel undergoes to an improvement of the rigidity compared to the parent (FY)3 assemblies as suggested by the storage modulus (G') that increases from 970 to 3360 Pa. The mechanical properties of FYFCFYF are compatible with its potential application in bone tissue regeneration. Moreover, the avalaibility of a Cys residue in the middle of the peptide sequence could allow the hydrogel derivatization with targeting moieties or with biologically relevant molecules.

Preparation of Composite Materials from Self-Assembled Chitin Nanofibers

Although chitin is a representative abundant polysaccharide, it is mostly unutilized as a material source because of its poor solubility and processability. Certain specific properties, such as biodegradability, biocompatibility, and renewability, make nanofibrillation an efficient approach for providing chitin-based functional nanomaterials. The composition of nanochitins with other polymeric components has been efficiently conducted at the nanoscale to fabricate nanostructured composite materials. Disentanglement of chitin microfibrils in natural sources upon the top-down approach and regeneration from the chitin solutions/gels with appropriate media, such as hexafluoro-2-propanol, LiCl/N, N-dimethylacetamide, and ionic liquids, have, according to the self-assembling bottom-up process, been representatively conducted to fabricate nanochitins. Compared with the former approach, the latter one has emerged only in the last one-and-a-half decade. This short review article presents the preparation of composite materials from the self-assembled chitin nanofibers combined with other polymeric substrates through regenerative processes based on the bottom-up approach.

Key Physicochemical Determinants in the Antimicrobial Peptide RiLK1 Promote Amphipathic Structures

Antimicrobial peptides (AMPs) represent a skilled class of new antibiotics, due to their broad range of activity, rapid killing, and low bacterial resistance. Many efforts have been made to discover AMPs with improved performances, i.e., high antimicrobial activity, low cytotoxicity against human cells, stability against proteolytic degradation, and low costs of production. In the design of new AMPs, several physicochemical features, such as hydrophobicity, net positive charge, propensity to assume amphipathic conformation, and self-assembling properties, must be considered. Starting from the sequence of the dodecapeptide 1018-K6, we designed a new 10-aminoacid peptide, namely RiLK1, which is highly effective against both fungi and Gram-positive and -negative bacteria at low micromolar concentrations without causing human cell cytotoxicity. In order to find the structural reasons explaining the improved performance of RiLK1 versus 1018-K6, a comparative analysis of the two peptides was carried out with a combination of CD, NMR, and fluorescence spectroscopies, while their self-assembling properties were analyzed by optical and atomic force microscopies. Interestingly, the different spectroscopic and microscopic profiles exhibited by the two peptides, including the propensity of RiLK1 to adopt helix arrangements in contrast to 1018-K6, could explain the improved bactericidal, antifungal, and anti-biofilm activities shown by the new peptide against a panel of food pathogens.

A Self-Assembling Amphiphilic Peptide Dendrimer-Based Drug Delivery System for Cancer Therapy

Despite being a mainstay of clinical cancer treatment, chemotherapy is limited by its severe side effects and inherent or acquired drug resistance. Nanotechnology-based drug-delivery systems are widely expected to bring new hope for cancer therapy. These systems exploit the ability of nanomaterials to accumulate and deliver anticancer drugs at the tumor site via the enhanced permeability and retention effect. Here, we established a novel drug-delivery nanosystem based on amphiphilic peptide dendrimers (AmPDs) composed of a hydrophobic alkyl chain and a hydrophilic polylysine dendron with different generations (AmPD KK₂ and AmPD KK₂K₄). These AmPDs assembled into nanoassemblies for efficient encapsulation of the anti-cancer drug doxorubicin (DOX). The AmPDs/DOX nanoformulations improved the intracellular uptake and accumulation of DOX in drug-resistant breast cancer cells and increased permeation in 3D multicellular tumor spheroids in comparison with free DOX. Thus, they exerted effective anticancer activity while circumventing drug resistance in 2D and 3D breast cancer models. Interestingly, AmPD KK₂ bearing a smaller peptide dendron encapsulated DOX to form more stable nanoparticles than AmPD KK₂K₄ bearing a larger peptide dendron, resulting in better cellular uptake, penetration, and anti-proliferative activity. This may be because AmPD KK₂ maintains a better balance between hydrophobicity and hydrophilicity to achieve optimal self-assembly, thereby facilitating more stable drug encapsulation and efficient drug release. Together, our study provides a promising perspective on the design of the safe and efficient cancer drug-delivery nanosystems based on the self-assembling amphiphilic peptide dendrimer.

Self-Assembled Nanobodies as Selectively Targeted, Nanostructured, and Multivalent Materials

Nanobodies represent valuable tools in advanced therapeutic strategies but their small size (∼2.5 × ∼ 4 nm) and limited valence for interactions might pose restrictions for in vivo applications, especially regarding their modest capacity for multivalent and cooperative interaction. In this work, modular protein constructs have been designed, in which nanobodies are fused to protein domains to provide further functionalities and to favor oligomerization into stable self-assembled nanoparticles. The nanobody specificity for their targets is maintained in such supramolecular complexes. Also, their diameter around 70 nm and multivalent interactivity should favor binding and penetrability into target cells via solvent-exposed receptor. These concepts have been supported by unrelated nanobodies directed against the ricin toxin (A3C8) and the Her2 receptor (EM1), respectively, that were modified with the addition of a reporter protein and a hexa-histidine tag at the C-terminus that promotes self-assembling. The A3C8-based nanoparticles neutralize the ricin toxin efficiently, whereas the EM1-based nanoparticles enable to selective imaging Her2-positive cells. These findings support the excellent extracellular and intracellular functionality of nanobodies organized in form of oligomeric nanoscale assemblies.

Living-Cell MicroRNA Imaging with Self-Assembling Fragments of Fluorescent Protein-Mimic RNA Aptamer

As the cellular roles of RNA abundance continue to increase, there is an urgent need for the corresponding tools to elucidate native RNA functions and dynamics, especially those of short, low-abundance RNAs in live cells. Fluorescent RNA aptamers provide a useful strategy to create the RNA tag and biosensor devices. Corn, which binds with 3,5-difluoro-4-hydroxybenzylidene-imidazolinone-2-oxime (DFHO), is a good candidate for the RNA tag because of its enhanced photostability and red-shifted spectrum. Herein, we report for the first time the utilization of Corn as a split aptamer system, combined with RNA-initiated fluorescence complementation (RIFC), for monitoring RNA self-assembly and sensing microRNA. In this platform, the 28-nt Corn was divided into two nonfunctional halves (named probe I and probe II), and an additional target RNA recognition and stem part was introduced in each probe. The target RNA can trigger the self-assembly reconstitution of the Corn's G-quadruplex scaffold for DFHO binding and turn-on fluorescence. These probes can be transfected stably into mammalian cells and deliver the light-up fluorescent response to microRNA-21 (miR-21). Significantly, the probes have good photostability, with minimal fluorescence loss after continuous irradiation, and can be used for imaging of miR-21 in living mammalian cells. The proposed method is universal and could be applied to the sensing of other tumor-associated RNAs, including messenger RNA and noncoding RNA, as well as for monitoring RNA/RNA interactions. The Corn-based splitting aptamers show promising potential in the real-time visualization and mechanistic analysis of nucleic acids.

Trifaceted Mickey Mouse Amphiphiles for Programmable Self-Assembly, DNA Complexation and Organ-Selective Gene Delivery

Instilling segregated cationic and lipophilic domains with an angular disposition in a trehalose-based trifaceted macrocyclic scaffold allows engineering patchy molecular nanoparticles leveraging directional interactions that emulate those controlling self-assembling processes in viral capsids. The resulting trilobular amphiphilic derivatives, featuring a Mickey Mouse architecture, can electrostatically interact with plasmid DNA (pDNA) and further engage in hydrophobic contacts to promote condensation into transfectious nanocomplexes. Notably, the topology and internal structure of the cyclooligosaccharide/pDNA co-assemblies can be molded by fine-tuning the valency and characteristics of the cationic and lipophilic patches, which strongly impacts the transfection efficacy in vitro and in vivo. Outstanding organ selectivities can then be programmed with no need of incorporating a biorecognizable motif in the formulation. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes by making cyclooligosaccharide patchiness the focus.

Self-Supporting Hydrogels Based on Fmoc-Derivatized Cationic Hexapeptides for Potential Biomedical Applications

Peptide-based hydrogels (PHGs) are biocompatible materials suitable for biological, biomedical, and biotechnological applications, such as drug delivery and diagnostic tools for imaging. Recently, a novel class of synthetic hydrogel-forming amphiphilic cationic peptides (referred to as series K), containing an aliphatic region and a Lys residue, was proposed as a scaffold for bioprinting applications. Here, we report the synthesis of six analogues of the series K, in which the acetyl group at the N-terminus is replaced by aromatic portions, such as the Fmoc protecting group or the Fmoc-FF hydrogelator. The tendency of all peptides to self-assemble and to gel in aqueous solution was investigated using a set of biophysical techniques. The structural characterization pointed out that only the Fmoc-derivatives of series K keep their capability to gel. Among them, Fmoc-K3 hydrogel, which is the more rigid one (G’ = 2526 Pa), acts as potential material for tissue engineering, fully supporting cell adhesion, survival, and duplication. These results describe a gelification process, allowed only by the correct balancing among aggregation forces within the peptide sequences (e.g., van der Waals, hydrogen bonding, and π–π stacking).

Novel temporin L antimicrobial peptides: promoting self-assembling by lipidic tags to tackle superbugs

The rapid development of antimicrobial resistance is pushing the search in the discovering of novel antimicrobial molecules to prevent and treat bacterial infections. Self-assembling antimicrobial peptides, as the lipidated peptides, are a novel and promising class of molecules capable of meeting this need. Based on previous work on Temporin L analogs, several new molecules lipidated at the N- or and the C-terminus were synthesised. Our goal is to improve membrane interactions through finely tuning self-assembly to reduce oligomerisation in aqueous solution and enhance self-assembly in bacterial membranes while reducing toxicity against human cells. The results here reported show that the length of the aliphatic moiety is a key factor to control target cell specificity and the oligomeric state of peptides either in aqueous solution or in a membrane-mimicking environment. The results of this study pave the way for the design of novel molecules with enhanced activities.

Autonomous spheroid formation by culture plate compartmentation

Scaffold-free 3D cell cultures (e.g. pellet cultures) are widely used in medical science, including cartilage regeneration. Their drawbacks are high time/reagent consumption and lack of early readout parameters. While optimisation was achieved by automation or simplified spheroid generation, most culture systems remain expensive or require tedious procedures. The aim of this study was to establish a system for resource efficient spheroid generation. This was achieved by compartmentation of cell culture surfaces utilising laser engraving (grid plates). This compartmentation triggered autonomous spheroid formation via rolling-up of the cell monolayer in human adipose-derived stem cells (ASC/TERT1) and human articular chondrocytes (hAC)-ASC/TERT1 co-cultures, when cultivated on grid plates under chondrogenic conditions. Plates with 3 mm grid size yielded stable diameters (about 300 μm). ASC/TERT1 spheroids fully formed within 3 weeks while co-cultures took 1-2 weeks, forming significantly faster with increasing hAC ratio (p<0.05 and 0.01 for 1:1 and 1:4 ASC/TERT1:hAC ratio respectively). Co-cultures showed slightly lower spheroid diameter, due to earlier spheroid formation and incomplete monolayer formation. However, this was associated with more regular matrix distribution in the co-culture. Both showed differentiation capacity comparable to standard pellet culture in (immune-)histochemistry and RT-qPCR. To assess usability for cartilage repair, spheroids were embedded into a hydrogel (fibrin), yielding cellular outgrowth and matrix deposition, which was especially pronounced in co-cultures. The herein presented novel cell culture system is not only a promising tool for autonomous spheroid generation with the potential of experimental and clinical application in tissue engineering but also for high-throughput analysis for both pharmaceutical and therapeutic uses.

Developing Protein-Antitumoral Drug Nanoconjugates as Bifunctional Antimicrobial Agents

A novel concept about bifunctional antimicrobial drugs, based on self-assembling protein nanoparticles, has been evaluated here over two biofilm-forming pathogens, namely Pseudomonas aeruginosa and Staphylococcus aureus. Two structurally different antimicrobial peptides (GWH1 and PaDBS1R1) were engineered to form regular nanoparticles of around 35 nm, to which the small molecular weight drug Floxuridine was covalently conjugated. Both the assembled peptides and the chemical, a conventional cytotoxic drug used in oncotherapy, showed potent antimicrobial activities that were enhanced by the combination of both molecules in single pharmacological entities. Therefore, the resulting prototypes show promises as innovative nanomedicines, being potential alternatives to conventional antibiotics. The biological performance and easy fabrication of these materials fully support the design of protein-based hybrid constructs for combined molecular therapies, expected to have broad applicability beyond antimicrobial medicines. In addition, the approach taken here validates the functional exploration and repurposing of antitumoral drugs, which at low concentrations perform well as unexpected biofilm-inhibiting agents.

Self-Assembly CNTs@PANi Coffee Rings on Poly(styrene-ethylene-butylene-styrene) Triblock Copolymer for Largely Stretchable Electronics

In this paper, CNTs@PANi nanocomposites were prepared by in-situ oxidation polymerization of aniline, and their structure, morphology and conductivity were characterized. A mixed solvent of toluene and tetrahydrofuran was used to prepare dispersions of CNTs@PANi and poly(styrene-ethylene-butylene-styrene) (SEBS) triblock copolymer, and bilayer composite film was prepared. According to the solvent phase separation and uneven evaporation flux, CNTs@PANi self-assembled into the interconnected coffee ring structure on the SEBS matrix. The prepared bilayer composite film had excellent stretchability, and the conductivity of the functional layer was close to that of CNTs@PANi, which could light up an LED lamp under 100% strain and restore the topological structure. Electrochemical tests showed that the bilayer film had obvious heterogeneity. The impedance characteristics of the CNTs@PANi functional layer and the SEBS matrix were analyzed, and its heterogeneous corrosion resistance mechanism further discussed.

Using a Self-Assembled Two-Dimensional MXene-Based Catalyst (2D-Ni@Ti3C2) to Enhance Hydrogen Storage Properties of MgH2

In this work, we report the remarkable catalytic effects of a novel Ti₃C₂ MXene-based catalyst (Ni@Ti-MX), which was prepared via self-assembling of Ni nanoparticles onto the surface of exfoliated Ti₃C₂ nanosheets. The resultant Ni@Ti-MX catalyst, characterized by ultradispersed Ni nanoparticles being anchored on the monolayer Ti₃C₂ flakes, was introduced into MgH₂ through ball milling. In situ transmission electron microscopy (TEM) analysis revealed that a synergetic catalytic effect of multiphase components (Mg₂Ni, TiO₂, metallic Ti, etc.) derived in the MgH₂ + Ni@Ti-MX composite exhibits remarkable improvements in the hydrogen sorption kinetics of MgH₂. In particular, the MgH₂ + Ni@Ti-MX composite can absorb 5.4 wt % H₂ in 25 s at 125 °C and release 5.2 wt % H₂ in 15 min at 250 °C. Interestingly, it can uptake 4 wt % H₂ in 5 h even at room temperature. Furthermore, the dehydrogenation peak temperature of the MgH₂ + Ni@Ti-MX composite is about 221 °C, which is 50 and 122 °C lower than that of MgH₂ + Ti-MX and MgH₂, respectively. The excellent hydrogen sorption properties of the MgH₂ + Ni@Ti-MX composite are primarily attributed to the peculiar core-shell nanostructured MgH₂@Mg₂NiH₄ hybrid materials and the interfacial coupling effects from different catalyst-matrix interfaces. The results obtained in this study demonstrate that using self-assembling of transition-metal elements on two-dimensional (2D) materials as a catalyst is a promising approach to enhance the hydrogen storage properties of MgH₂.

Formation of Self-Assembled Anticorrosion Films on Different Metals

The review will first discuss shortly the phenomenon of corrosion and enroll some general possibilities to decrease the rate of this deterioration. The stress will be laid upon the presentation of anticorrosive self-assembled molecular (SAM) layers as well as on the preparation technology that is a simple technique, does not need any special device, and can be applied on different solids (metals or non-metals) alone or in combination. The paper groups the chemicals (mainly amphiphiles) that can develop nanolayers on different pure or oxidized metal surfaces. The history of the self-assembled molecular layer will be discussed from the beginning of the first application up to now. Not only the conditions of the nanofilm preparation as well as their characterization will be discussed, but the methods that can evaluate the corrosion-inhibiting efficiency of the SAM layers under a corrosive environment will be demonstrated as well.

Self-Assembling Cyclodextrin-Based Nanoparticles Enhance the Cellular Delivery of Hydrophobic Allicin

Most chemotherapeutics are hydrophobic molecules and need to be converted into hydrophilic formulations before administration. To address this issue, a novel cyclodextrin-based nanoparticle was proposed as a versatile carrier for cellular delivery of hydrophobic molecules. First, the effect of the polylysine (PL)/NH₂-β-cyclodextrin (NH₂-β-CD) ratio on particle size and encapsulation efficiency in prepared complexes was investigated. Subsequently, transmission electron microscopy images showed that the sizes of PL/NH₂-β-CD nanoparticles ranging from 10 to 260 nm decreased with the reduction in the PL/NH₂-β-CD ratio, which was completely consistent with the findings of size distributions. At a PL/NH₂-β-CD ratio of 10, the surface charge on the PL/NH₂-β-CD nanoparticle was maximized at (+52.8 mV), and encapsulation efficiency was optimal (47.2%), which revealed a great advantage in delivery of hydrophobic allicin. In addition, the positive charge of PL chains facilitated the cellular uptake of the PL/NH₂-β-CD-DOX by interacting with the negatively charged cell membrane. Conclusively, this study suggests that the combination of allicin and PL/NH₂-β-CD nanoparticles acting on the S and G2/M phases in cell cycle regulation induces apoptosis and exhibits substantial application in killing cancer cells.

New Human Islet Amyloid Polypeptide Fragments Susceptible to Aggregation

Human Islet Amyloid Polypeptide (hIAPP) plays a key role in the pathogenesis of type II diabetes. The aim of this research was to search for new amyloidogenic fragments of hIAPP. An initial attempt to predict the amyloidogenic cores of polypeptides/proteins using five different computer programs did not provide conclusive results. Therefore, we synthesized hIAPP fragments covering the entire hormone. The fragments were assessed for their aggregation ability, using recommended methods to search for the amyloidogenic fragments of the polypeptides/proteins. It was found that fragments (18-22) H-HSSNN-OH and (33-37) H-GSNTY-NH₂ aggregate and form stable amyloid-like structures. Both of these fragments have a much higher antiproliferative activity relative to the RIN-5F cell compared to the (23-27) H-FGAIL-OH fragment widely regarded as the amyloidogenic core of amylin. The analog of (33-37) H-GSNTY-NH₂ containing a free carboxy group on the C-terminal amino acid (H-GSNTY-OH) does not have amyloidogenic properties and can therefore be considered as a potential inhibitor of amylin aggregation. Research on the use of non-aggregating amylin fragments as potential hormone aggregation inhibitors is ongoing.

Development of Novel Heparin/Protamine Nanoparticles Useful for Delivery of Exogenous Proteins In Vitro and In Vivo

We previously reported that heparin/protamine particles (LHPPs) produced as nanoparticles through simple mixing of raw materials exhibit sustained protein release and can be retained in cells. In the present study, we modified LHPPs without employing any organic synthetic approach. The resulting LHPPs were re-named as improved LHPPs (i-LHPPs) and have the ability to retain cell-penetrating peptides (GRKKRRQRRRPPQ) based on electrostatic interactions. We examined whether i-LHPPs can introduce exogenous proteins (i.e., lacZ protein encoding bacterial β-galactosidase) into cultured cells in vitro, or into murine hepatocytes in vivo through intravenous injection to anesthetized mice. We found an accumulation of the transferred protein in both in vitro cultured cells and in vivo hepatocytes. To the best of our knowledge, reports of successful in vivo delivery to hepatocytes are rare. The i-LHPP-based protein delivery technique will be useful for in vivo functional genetic modification of mouse hepatocytes using Cas9 protein-mediated genome editing targeting specific genes, leading to the creation of hepatic disease animal models for research that aims to treat liver diseases.