Beneficial synergy of adsorption-intercalation-conversion mechanisms in Nb₂O₅@nitrogen-doped carbon frameworks for promoted removal of metal ionsviahybrid capacitive deionization

Capacitive deionization (CDI) is an emerging water purification technology, but the ion adsorption capacity of traditional carbon-based CDI electrodes is still unsatisfactory. Herein, a novel faradaic electrode by anchoring Nb2O5nanoparticles on nitrogen-doped carbon frameworks as anodes and activated carbon (AC) as cathodes in a hybrid capacitive deionization (HCDI) system was originally developed to capture Na+ionsviaadsorption-intercalation-conversion mechanisms. The synergistic effects of the nanostructure and carbon coating were beneficial to enhancing electrical conductivity and offering fast Na+ion diffusion pathways. Impressively, the HCDI system demonstrated an excellent ion adsorption capacity of 35.4 mg g−1in a 500 mg L−1NaCl solution at 1.2 V as well as stable regeneration ability.In situRaman andex situXPS measurements unraveled that the mechanism of ion removal from water was the reversible redox reaction of Nb2O5. The new overall understanding of the synergistic effects opens opportunities for the design of HCDI systems for efficient removal of metal ions from saline water.</p

Erythrocyte Membrane Modified Janus Polymeric Motors for Thrombus Therapy

We report the construction of erythrocyte membrane-cloaked Janus polymeric motors (EM-JPMs) which are propelled by near-infrared (NIR) laser irradiation and are successfully applied in thrombus ablation. Chitosan (a natural polysaccharide with positive charge, CHI) and heparin (glycosaminoglycan with negative charge, Hep) were selected as wall materials to construct biodegradable and biocompatible capsules through the layer-by-layer self-assembly technique. By partially coating the capsule with a gold (Au) layer through sputter coating, a NIR-responsive Janus structure was obtained. Due to the asymmetric distribution of Au, a local thermal gradient was generated upon NIR irradiation, resulting in the movement of the JPMs through the self-thermophoresis effect. The reversible "on/off" motion of the JPMs and their motile behavior were easily tuned by the incident NIR laser intensity. After biointerfacing the Janus capsules with an erythrocyte membrane, the EM-JPMs displayed red blood cell related properties, which enabled them to move efficiently in relevant biological environments (cell culture, serum, and blood). Furthermore, this therapeutic platform exhibited excellent performance in ablation of thrombus through photothermal therapy. As man-made micromotors, these biohybrid EM-JPMs hold great promise of navigating in vivo for active delivery while overcoming the drawbacks of existing synthetic therapeutic platforms. We expect that this biohybrid motor has considerable potential to be widely used in the biomedical field

Chromatin Remodeling of Colorectal Cancer Liver Metastasis is Mediated by an HGF‐PU.1‐DPP4 Axis

Colorectal cancer (CRC) metastasizes mainly to the liver, which accounts for the majority of CRC-related deaths. Here it is shown that metastatic cells undergo specific chromatin remodeling in the liver. Hepatic growth factor (HGF) induces phosphorylation of PU.1, a pioneer factor, which in turn binds and opens chromatin regions of downstream effector genes. PU.1 increases histone acetylation at the DPP4 locus. Precise epigenetic silencing by CRISPR/dCas9KRAB or CRISPR/dCas9HDAC revealed that individual PU.1-remodeled regulatory elements collectively modulate DPP4 expression and liver metastasis growth. Genetic silencing or pharmacological inhibition of each factor along this chromatin remodeling axis strongly suppressed liver metastasis. Therefore, microenvironment-induced epimutation is an important mechanism for metastatic tumor cells to grow in their new niche. This study presents a potential strategy to target chromatin remodeling in metastatic cancer and the promise of repurposing drugs to treat metastasis

Bio-inspired short peptide self-assembly: From particles to functional materials

Natural systems are typically featured with tremendous molecular complexity and construct exquisite architectures and functional materials through precise spatial and temporal control. Supramolecular selfassembly from peptides and proteins is believed to be the key player. Thus, knowledge of the fundamental mechanisms driving peptides into vast functional hierarchical structures will certainly help the rational control of self-assembly process, leading to more precise structural organization and functional optimization. In this review, we briefly summarize the recent progress of this burgeoning field mainly from two directions: peptide-based self-assembly and co-assembly with other functional molecules, each part is further divided into two subparts and representative examples are given for each subpart according to their development timeline. At the end of each part, brief summaries of the closely related applications are outlined. For the closing remarks, we conclude with our own understanding of the area and perspectives are given based on recent developments. Overall, this review could be suitable for both new readers to gain a comprehensive overview of the area and experienced readers to get a summary of the development in short peptide self-assembly from particles to functional materials. (c) 2021 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

Engineering and delivery of nanocolloids of hydrophobic drugs

A lot of efforts have been devoted to engineering the delivery of hydrophobic drugs due to the high demand of chemotherapy against cancer. While early developed liposomes and polymeric nanoparticles did not meet the requirements of high drug loading efficiency, pure drug nanoparticles appeared to meet these together with high stability. Current drug delivery systems demand an improved performance over the whole aspects of stability, loading capacity, and therapeutic effects. As a result, both new techniques based on traditional methods and totally new procedures are under investigation. In this review, we focus on the evaluation of pure drug nanolloids fabricated by different engineering protocols with emphasis on the size and morphology, delivery and controlled release, and therapeutic effects of these drug nanocolloids.</p

A versatile cyclic dipeptide hydrogelator: Self-assembly and rheology in various physiological conditions

Peptide-based supramolecular hydrogels as functional soft materials hold great promising for biomedical applications. However, much effort has been devoted to the finding and development of linear peptide hydrogelators and related hydrogel materials. Usually, linear peptide hydrogels are subject to the environmental variations and suffer from rapid enzymatic degradation in physiological conditions, limiting their more broad range of applications. Herein, we discover that a cyclic dipeptide (Cyclo-(Leu-Phe), CLF) can serve as a versatile hydrogelator for formation of supramolecular hydrogels at various physiological and harsh environments including the presence of salts, proteins and enzymes as well as acidic and basic aqueous solutions. Importantly, the CLF hydrogels show robust stability and excellent rheological properties at the various conditions, which are attributable to the rigid molecular structure of cyclic dipeptides and their strong 3-dimentional intermolecular hydrogen bonding networks. Hence, cyclic dipeptides provide a new alternative for development of peptide-based hydrogel materials with properties and functions more adapted for the complex and harsh environments.</p

Water-Insoluble Photosensitizer Nanocolloids Stabilized by Supramolecular Interfacial Assembly towards Photodynamic Therapy

Nanoengineering of hydrophobic photosensitizers (PSs) is a promising approach for improved tumor delivery and enhanced photodynamic therapy (PDT) efficiency. A variety of delivery carriers have been developed for tumor delivery of PSs through the enhanced permeation and retention (EPR) effect. However, a high-performance PS delivery system with minimum use of carrier materials with excellent biocompatibility is highly appreciated. In this work, we utilized the spatiotemporal interfacial adhesion and assembly of supramolecular coordination to achieve the nanoengineering of water-insoluble photosensitizer Chlorin e6 (Ce6). The hydrophobic Ce6 nanoparticles are well stabilized in a aqueous medium by the interfacially-assembled film due to the coordination polymerization of tannic acid (TA) and ferric iron (Fe(III)). The resulting Ce6@ TA-Fe(III) complex nanoparticles (referenced as Ce6@ TA-Fe(III) NPs) significantly improves the drug loading content (similar to 65%) and have an average size of 60 nm. The Ce6@TA-Fe(III) NPs are almost non-emissive as the aggregated states, but they can light up after intracellular internalization, which thus realizes low dark toxicity and excellent phototoxicity under laser irradiation. The Ce6@TA-Fe(III) NPs prolong blood circulation, promote tumor-selective accumulation of PSs, and enhanced antitumor efficacy in comparison to the free-carrier Ce6 in vivo evaluation.</p

Self-Assembled Injectable Peptide Hydrogels Capable of Triggering Antitumor Immune Response

Self-assembled peptide hydrogels are particularly appealing for drug delivery, tissue engineering, and antitumor therapy due to various advantageous features including excellent biocompatibility and biodegradability, defined molecular and higher organized structures, and easy availability. However, the poor mechanical and rheological properties of assembled peptide hydrogels cause difficulties in injection, thus limiting further applications. Herein, injectable peptide-based hydrogels with tunable mechanical and rheological properties were obtained by combination with a positively charged poly peptide (poly-L-lysine, PLL). Electrostatic coupling between PLL and a self-assembling dipeptide (Fmoc-FF) provides a smart switch to enable the fibrous hydrogels to be shear-thinning and self-healing, thus leading to the formation of supramolecular hydrogels with rheological properties suitable for injection. The latter can be flexibly adjusted by merely varying the concentration or the molecular weight of the polypeptide to satisfy a variety of requirements in biological applications. The hydrogels, consisting of helical nanofibers stabilized with disulfide bonds, are prepared and further injected for antitumor therapy. The results demonstrate that the helical fibrous hydrogel, without the addition of antigens, immune regulatory factors, and adjuvants, can activate T cell response and efficiently suppress tumor growth. Therefore, injectable hydrogels self-assembled by a combination of small peptides and biomacromolecules present a great potential for biomedical applications, especially for development of a new type of immuno-responsive materials toward antitumor therapy.</p

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

Robust Photothermal Nanodrugs Based on Covalent Assembly of Nonpigmented Biomolecules for Antitumor Therapy

Photothermal nanodrugs based on biomolecules are critically important for advancing photothermal therapy (PTT). However, constructing photothermal nano drugs from biomolecules is highly challenging because most biomolecules are inherently nonpigmented. Herein, we synthesize well-defined, uniform photothermal nanodrugs through a covalent assembly approach by using nonpigmented peptides and iridoids as building blocks. The resulting photothermal nanodrugs show broad absorption from the UV to the near-infrared region, high photothermal conversion efficiency along with robust photostability, and selective tumor accumulation, leading to highly efficient tumor ablation via PTT. This work represents the first example of photothermal nanodrugs that can be constructed by using nonpigmented biomolecules as building blocks and thus will conceivably promote the preclinical evaluation and clinical translation of PTT