Cobalt-Directed Assembly of Antibodies onto Metal-Phenolic Networks for Enhanced Particle Targeting

A tunable LDI-MS platform assisted by metal-phenolic network-coated AuNPs for sensitive and customized detection of amino acids

This study introduces a novel approach for the sensitive and accurate detection of small molecule metabolites, employing metal-phenolic network (MPN) functionalized AuNPs as both adsorbent and matrix to enhance laser desorption/ionization mass spectrometry (LDI-MS) performance. The MPN comprising tannic acid (TA) and transition metal ions (Fe3+, Co2+, Ni2+, Cu2+, or Zn2+) was coated on the surface of AuNPs, forming metal-TA network-coated AuNPs (M-TA@AuNPs). The M-TA@AuNPs provided a tunable surface for specific interactions with analytes, displaying distinct enrichment efficacies for different amino acids, especially for Cu-TA@AuNPs exhibiting the highest affinity for histidine (His). Under the optimized condition, the proposed method enabled ultrasensitive detection of His, with good linearity (R2 = 0.9627) in the low-concentration range (50 nM-1 μM) and a limit of detection (LOD) as low as 0.9 nM. Furthermore, the method was successfully applied to detect His from human urine samples, showcasing its practical applications in clinical diagnostics, particularly in the realm of amino acid-based targeted metabolomics.

Recent advances of copper-based metal phenolic networks in biomedical applications

Metal-phenolic Networks (MPNs) are a novel class of nanomaterial developed gradually in recent years which are self-assembled by metal ions and polyphenolic ligands. Due to their environmental protection, good adhesion, and biocompatibility with green phenolic ligands, MPNs can be used as a new type of nanomaterial. They show excellent properties such as anti-inflammatory, antioxidant, antibacterial, and anticancer, and have been widely studied in the biomedical field. As one of the most common subclasses of the MPNs family, copper-based MPNs have been widely studied for drug delivery, Photodynamic Therapy (PDT), Chemo dynamic Therapy (CDT), antibacterial and anti-inflammatory, bone tissue regeneration, skin regeneration wound repair, and metal ion imaging. In this paper, the preparation strategies of different types of copper-based MPNs are reviewed. Then, the application status of copper-based MPNs in the biomedical field under different polyphenol ligands is introduced in detail. Finally, the existing problems and challenges of copper-based MPNs are discussed, as well as their future application prospects in the biomedical field.

Metal-phenolic network composites: from fundamentals to applications

Composites with tailored compositions and functions have attracted widespread scientific and industrial interest. Metal-phenolic networks (MPNs), which are composed of phenolic ligands and metal ions, are amorphous adhesive coordination polymers that have been combined with various functional components to create composites with potential in chemistry, biology, and materials science. This review aims to provide a comprehensive summary of both fundamental knowledge and advancements in the field of MPN composites. The advantages of amorphous MPNs, over crystalline metal-organic frameworks, for fabricating composites are highlighted, including their mild synthesis, diverse interactions, and numerous intrinsic functionalities. The formation mechanisms and state-of-the-art synthesis strategies of MPN composites are summarized to guide their rational design. Subsequently, a detailed overview of the chemical interactions and structure-property relationships of composites based on different functional components (e.g., small molecules, polymers, biomacromolecules) is provided. Finally, perspectives are offered on the current challenges and future directions of MPN composites. This tutorial review is expected to serve as a fundamental guide for researchers in the field of metal-organic materials and to provide insights and avenues to enhance the performance of existing functional materials in applications across diverse fields.

MPNTEXT: An Interactive Platform for Automatically Extracting Metal-Polyphenol Networks and Their Applications from Scientific Literature

In recent years, metal-polyphenol networks (MPNs) have gained significant attention due to their unique properties and broad applications across various fields. However, the burgeoning volume of MPN literature necessitates the automation of chemical information extraction from the extensive corpus of unstructured data, including scientific publications. To address this challenge, we proposed a platform named MPNTEXT, which utilized natural language processing techniques and machine learning algorithms to efficiently identify and extract pertinent information, thereby assisting users in comprehending complex MPNs and their textual descriptions of applications. Users can enter keywords, such as "Fe", "drug delivery", or "tannic acid", to retrieve relevant information, which is then presented in a structured format. This study aims to provide a user-friendly tool for collecting and retrieving MPN data and promotes data-driven material design. The platform offers researchers a more convenient and efficient way to design versatile MPNs and explore their applications.

A smartphone-based fluorescent biosensor with metal-organic framework biocomposites and cotton swabs for the rapid determination of tetrodotoxin in seafood

BACKGROUND

Tetrodotoxin (TTX) is a potent neurovirulent marine biotoxin that is present in puffer fish and certain marine animals. It is capable of causing severe neurotoxic symptoms and even death when consumed through contaminated seafood. Due to its high toxicity, developing an effective assay for TTX determination in seafood has significant benefits for food safety and human health. Currently, it remains challenging to achieve on-site determination of TTX in seafood. To facilitate mass on-site assays, more affordable technologies utilizing accessible equipment that require no skilled personnel are needed.

RESULTS

A smartphone-based portable fluorescent biosensor is proposed for TTX determination by using metal-organic framework (MOF) biocomposites and cotton swabs. Oriented antibody (Ab)-decorated and fluorescent quantum dot (QD)-loaded MOF biocomposites (QD@MOF*Ab) are rapidly synthesized for binding targets and fluorescent responses by utilizing the tunability of zinc-based MOF. Moreover, facile Ab-immobilized household cotton swabs are utilized as TTX capture tools. TTX forms sandwich immune complexes with QD@MOF*Ab probes, achieving signal amplification. These probes are excited by a portable device to generate bright fluorescent signals, which can be detected by the naked eye, and TTX quantitative results are obtained using a smartphone. When observed with the naked eye, the limit of detection (LOD) is 0.4 ng/mL, while intelligent quantitation presents an LOD of 0.13 ng/mL at logarithmic concentrations of 0.2-400 ng/mL.

SIGNIFICANCE

This biosensor is convenient to use, and an easy-to-operate analysis is completed within 15 min, thus demonstrating excellent performance in terms of detection speed and portability. Furthermore, it successfully determines TTX contents in puffer fish and clam samples, demonstrating its potential for monitoring seafood. Herein, this work provides a favorable rapid sensing platform that is easily portable.

A coordinative modular assembly-constructed self-reinforced nano-therapeutic agent for effective antitumor-immune activation

Immunosuppressive microenvironment and poor immunogenicity are two stumbling blocks in anti-tumor immune activation. Tumor associated macrophages (TAMs) play crucial roles in immunosuppressive microenvironment, while immunogenic cell death (ICD) is a typical strategy to boost immunogenicity. Herein, we developed a coordinative modular assembly-based self-reinforced nanoparticle, (CaO2/TA)-(Fe3+/BSA) which integrated CaO2, Fe3+-tannic acid coordinated networks and albumin under the instruction of molecular dynamics simulation. (CaO2/TA)-(Fe3+/BSA) could significantly enhance Fenton reaction through Fe3+ self-reduction and H2O2 self-sufficiency, and simultaneously increased intracellular accumulation of Ca2+. The self-augmented Fenton reaction with sufficient reactive oxygen species effectively repolarized TAMs and elicited ICD with Ca2+ overload. Besides, (CaO2/TA)-(Fe3+/BSA) was confirmed to self-reinforce deep tumor drug delivery by "treatment-delivery" positive feedback based on gp60-mediated transcytosis and M2-like macrophages repolarization-mediated perfusion promotion. Resultantly, (CaO2/TA)-(Fe3+/BSA) effectively alleviated immunosuppression, provoked local and systemic immune response and potentiated anti-PD-1 antibody therapy. Our strategy highlights a facile and controllable approach to construct penetrated effective antitumor nano-immunotherapeutic agent.

Oxidative Coupling and Self-Assembly of Polyphenols for the Development of Novel Biomaterials

In recent years, the development of biomaterials from green organic sources with nontoxicity and hyposensitivity has been explored for a wide array of biotherapeutic applications. Polyphenolic compounds have unique structural features, and self-assembly by oxidative coupling allows molecular species to rearrange into complex biomaterial that can be used for multiple applications. Self-assembled polyphenolic structures, such as hollow spheres, can be designed to respond to various chemical and physical stimuli that can release therapeutic drugs smartly. The self-assembled metallic-phenol network (MPN) has been used for modulating interfacial properties and designing biomaterials, and there are several advantages and challenges associated with such biomaterials. This review comprehensively summarizes current challenges and prospects of self-assembled polyphenolic hollow spheres and MPN coatings and self-assembly for biomedical applications.

Functions of metal-phenolic networks and polyphenol derivatives in photo(electro)catalysis

Phenolic compounds are ubiquitous in nature because of their unique physical and chemical properties and wide applications, which have received extensive research attention. Phenolic compounds represented by tannic acid (TA) play an important role at the nanoscale. TA with a polyphenol hydroxyl structure can chemically react with organic or inorganic materials, among which metal-phenolic networks (MPNs) formed by coordination with metal ions and polyphenol derivatives formed by interactions with organic matter, exhibit specific properties and functions, and play key roles in photo(electro)catalysis. In this paper, we first introduce the fundamental properties of TA, then summarize the factors influencing the properties of MPNs and structural transformation of polyphenol-derived materials. Subsequently, the functions of MPNs and polyphenol derivatives in photo(electro)catalysis reactions are summarized, encompassing improving interfacial charge carrier separation, accelerating surface reaction kinetics, and enhancing light absorption. Finally, this article provides a comprehensive overview of the challenges and outlook associated with MPNs. Additionally, it presents novel insights into their stability, mechanistic analysis, synthesis, and applications in photo(electro)catalysis.

Design and investigation of targeting agent orientation and density on nanoparticles for enhancing cellular uptake efficiency

The design of targeting agent-conjugated systems is attracting much attention in cell targeted delivery and cancer therapy. However, quantitative study of the ligand density and binding efficiency is still limited due to the technical matters and tedious work involved. In this article, benzoboroxole-modified core-shell magnetic nanoparticles (MSP-AOPB NPs) as a drug carrier model were fabricated and transferrin (Tf) was immobilized on the nanoparticle surface in a site-oriented manner (Tf-MSP-AOPB NPs). The preparation conditions were investigated in detail to optimize the Tf binding efficiency. A suitable reaction temperature, time or initial feeding amount could significantly increase the Tf binding amount. The maximum Tf binding amount on the MSP-AOPB NPs was 184 mg g-1, and the targeting ligand density on the surface could be well controlled by simply adjusting the reaction conditions. In vitro studies demonstrated the excellent Tf-mediated targeting ability and enhanced cellular uptake efficacy by varying the ligand density. The optimal ligand binding amount for achieving the highest cellular uptake efficiency was 94 mg Tf/g, which corresponds to a ligand binding density of about 0.05 Tf/nm2, and the binding efficiency of conjugation was higher than 90%. Moreover, Tf-MSP-AOPB NPs prepared by a site-oriented conjugation strategy showed the best cell targeting ability, and their cellular uptake amount was 25 and 127 times higher than that of physical adsorption and EDC/NHS coupling reaction in HepG2 cells, respectively. This study provides a facile site-oriented bioconjugation technique for different kinds of antibodies, and a suitable ligand density can be easily attained to enhance the cellular uptake efficacy, which shows great significance for targeted delivery and cancer therapy.

Organic electrochemical transistor-based immuno-sensor using platinum loaded CeO2 nanosphere-carbon nanotube and zeolitic imidazolate framework-enzyme-metal polyphenol network

This work demonstrates an organic electrochemical transistor (OECT) immuno-sensor with a detection limit down to fg mL^-1. The OECT device transforms the antibody-antigen interaction signal by using the zeolitic imidazolate framework-enzyme-metal polyphenol network nanoprobe, which can produce electro-active substance (H₂O₂) through the enzyme-catalytic reaction. The produced H₂O₂ is subsequently electrochemically oxidized at the platinum loaded CeO₂ nanosphere-carbon nanotube modified gate electrode, resulting in an amplified current response of the transistor device. This immuno-sensor realizes the selective determination of vascular endothelial growth factor 165 (VEGF₁₆₅) down to the concentration of 13.6 fg mL^-1. It also shows good applicable capacity for determining the VEGF₁₆₅ that human brain microvascular endothelial cells and U251 human glioblastomas cells secreted in the cell culture medium. The ultrahigh sensitivity of the immuno-sensor is derived from excellent performances of the nanoprobe for enzyme loading and the OECT device for H₂O₂ detection. This work may provide a general way to fabricate the OECT immuno-sensing device with high performances.

Selective Valorization of Glycerol to Formic Acid on a BiVO4 Photoanode through NiFe Phenolic Networks

The integration of the glycerol oxidation reaction (GOR) with the hydrogen evolution reaction in photoelectrochemical (PEC) cells is a desirable alternative to PEC water splitting since a large quantity of glycerol is easily accessible as the byproduct from the biodiesel industry. However, the PEC valorization of glycerol to the value-added products suffers from low Faradaic efficiency and selectivity, especially in acidic conditions, which is beneficial for hydrogen production. Herein, by loading bismuth vanadate (BVO) with a robust catalyst composed of phenolic ligands (tannic acid) coordinated with Ni and Fe ions (TANF), we demonstrate a modified BVO/TANF photoanode for the GOR with a remarkable Faradaic efficiency of over 94% to value-added molecules in a 0.1 M Na₂SO₄/H₂SO₄ (pH = 2) electrolyte. The BVO/TANF photoanode achieved a high photocurrent of 5.26 mA·cm^-2 at 1.23 V versus reversible hydrogen electrode under 100 mW/cm² white light irradiation for formic acid production with 85% selectivity, equivalent to 573 mmol/(m²·h). Transient photocurrent and transient photovoltage techniques and electrochemical impedance spectroscopy along with intensity-modulated photocurrent spectroscopy indicated that the TANF catalyst could accelerate hole transfer kinetics and suppress charge recombination. Comprehensive mechanistic investigations reveal that the GOR is initiated by the photogenerated holes of BVO, while the high selectivity to formic acid is attributed to the selective adsorption of primary hydroxyl groups in glycerol on TANF. This study provides a promising avenue for highly efficient and selective formic acid generation from biomass in acid media via PEC cells.

Direct synthesis of amorphous coordination polymers and metal–organic frameworks

Coordination polymers (CPs) and their subset, metal-organic frameworks (MOFs), can have porous structures and hybrid physicochemical properties that are useful for diverse applications. Although crystalline CPs and MOFs have received the most attention to date, their amorphous states are of growing interest as they can be directly synthesized under mild conditions. Directly synthesized amorphous CPs (aCPs) can be constructed from a wider range of metals and ligands than their crystalline and crystal-derived counterparts and demonstrate numerous unique material properties, such as higher mechanical robustness, increased stability and greater processability. This Review examines methods for the direct synthesis of aCPs and amorphous MOFs, as well as their properties and characterization routes, and offers a perspective on the opportunities for the widespread adoption of directly synthesized aCPs.

Site-Specific Antibody Assembly on Nanoparticles via a Versatile Coating Method for Improved Cell Targeting

Antibody-nanoparticle conjugates are promising candidates for precision medicine. However, developing a controllable method for conjugating antibodies to nanoparticles without compromising the antibody activity represents a critical challenge. Here, a facile and generalizable film-coating method is presented using zeolitic imidazole framework-8 (ZIF-8) to immobilize antibodies on various nanoparticles in a favorable orientation for enhanced cell targeting. Different model and therapeutic antibodies (e.g., Herceptin) are assembled on nanoparticles via a biomineralized film-coating method and exhibited high antibody loading and targeting efficiencies. Importantly, the antibodies selectively bind to ZIF-8 via their Fc regions, which favorably exposes the functional Fab regions to the biological target, thus improving the cell targeting ability of antibody-coated nanoparticles. In combination, molecular dynamics simulations and experimental studies on antibody immobilization, orientation efficiency, and biofunctionality collectively demonstrate that this versatile site-specific antibody conjugation method provides effective control over antibody orientation and leads to improved cell targeting for a variety of nanoparticles.

Overcoming the On-Target Toxicity in Antibody-Mediated Therapies via an Indirect Active Targeting Strategy

Antibody-based therapies could be led astray when target receptors are expressed on nontarget sites, and the on-target toxicity poses critical challenges to clinical applications. Here, a biomimetic indirect active targeting (INTACT) strategy is proposed based on receptor expression disparities between nontarget sites and the targets. By prebinding the antibodies using cell membrane vesicles with appropriate receptor expressions, the INTACT strategy could filter out the interactions on nontarget sites due to their inferior receptor expression, whereas ensure on-demand release at the targets by competitive binding. The strategy is verified on CD47 antibody, realizing drastic alleviation of its clinically concerned hematotoxicity on a series of animal models including humanized patient-derived xenograft platforms, accompanied by preferable therapeutic effects. Furthermore, the INTACT strategy proves extensive applicability for various systems including antibody, antibody-drug conjugate, and targeted delivery systems, providing a potential platform refining the specificity for frontier antibody-related therapies.

Zinc-Epigallocatechin-3-gallate Network-Coated Nanocomposites against the Pathogenesis of Amyloid-Beta

The aggregation of amyloid beta (Aβ) is a hallmark of Alzheimer's disease (AD), a major cause of dementia and an unmet challenge in modern medicine. In this study, we constructed a biocompatible metal-phenolic network (MPN) comprising a polyphenol epigallocatechin gallate (EGCG) scaffold coordinated by physiological Zn(II). Upon adsorption onto gold nanoparticles, the MPN@AuNP nanoconstruct elicited a remarkable potency against the amyloid aggregation and toxicity of Aβ in vitro. The superior performance of MPN@AuNP over EGCG@AuNP was attributed to the porosity and hence larger surface area of the MPN in comparison with that of EGCG alone. The atomic detail of Zn(II)-EGCG coordination was unraveled by density functional theory calculations and the structure and dynamics of Aβ aggregation modulated by the MPN were further examined by discrete molecular dynamics simulations. As MPN@AuNP also displayed a robust capacity to cross a blood-brain barrier model through the paracellular pathway, and given the EGCG's function as an anti-amyloidosis and antioxidation agent, this MPN-based strategy may find application in regulating the broad AD pathology beyond protein aggregation inhibition.

Anti-oxidant anti-inflammatory and antibacterial tannin-crosslinked citrate-based mussel-inspired bioadhesives facilitate scarless wound healing

The revolutionary role of tissue adhesives in wound closure, tissue sealing, and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing. In contrast to the use of traditionally utilized toxic oxidative crosslinking initiators (exemplified by sodium periodate and silver nitrate), herein, the natural polyphenolic compound tannic acid (TA) was used to achieve near instantaneous (<25s), hydrogen bond mediated gelation of citrate-based mussel-inspired bioadhesives combining anti-oxidant, anti-inflammatory, and antimicrobial activities (3A-TCMBAs). The resulting materials were self-healing and possessed low swelling ratios (<60%) as well as considerable mechanical strength (up to ∼1.0 MPa), elasticity (elongation ∼2700%), and adhesion (up to 40 kPa). The 3A-TCMBAs showed strong in vitro and in vivo anti-oxidant ability, favorable cytocompatibility and cell migration, as well as photothermal antimicrobial activity against both Staphylococcus aureus and Escherichia coli (>90% bacterial death upon near-infrared (NIR) irradiation). In vivo evaluation in both an infected full-thickness skin wound model and a rat skin incision model demonstrated that 3A-TCMBAs + NIR treatment could promote wound closure and collagen deposition and improve the collagen I/III ratio on wound sites while simultaneously inhibiting the expression of pro-inflammatory cytokines. Further, phased angiogenesis was observed via promotion in the early wound closure phases followed by inhibition and triggering of degradation & remodeling of the extracellular matrix (ECM) in the late stage (supported by phased CD31 (platelet endothelial cell adhesion molecule-1) PDGF (platelet-derived growth factor) and VEGF (vascular endothelial growth factor) expression as well as elevated matrix metalloprotein-9 (MMP-9) expression on day 21), resulting in scarless wound healing. The significant convergence of material and bioactive properties elucidated above warrant further exploration of 3A-TCMBAs as a significant, new class of bioadhesive.

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Citrate-based mussel-inspired bioadhesive prepolymers were crosslinked with tannic acid via hydrogen bonding (3A-TCMBAs).

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3A-TCMBAs showed good tissue adhesiveness, self-healing and elastic properties.

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3A-TCMBAs exhibited photothermal antibacterial, antioxidant and anti-inflammatory efficiency.

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3A-TCMBAs could promote scarless wound healing by enabling phased angiogenesis.

Predicting protein function and orientation on a gold nanoparticle surface using a residue-based affinity scale

The orientation adopted by proteins on nanoparticle surfaces determines the nanoparticle's bioactivity and its interactions with living systems. Here, we present a residue-based affinity scale for predicting protein orientation on citrate-gold nanoparticles (AuNPs). Competitive binding between protein variants accounts for thermodynamic and kinetic aspects of adsorption in this scale. For hydrophobic residues, the steric considerations dominate, whereas electrostatic interactions are critical for hydrophilic residues. The scale rationalizes the well-defined binding orientation of the small GB3 protein, and it subsequently predicts the orientation and active site accessibility of two enzymes on AuNPs. Additionally, our approach accounts for the AuNP-bound activity of five out of six additional enzymes from the literature. The model developed here enables high-throughput predictions of protein behavior on nanoparticles, and it enhances our understanding of protein orientation in the biomolecular corona, which should greatly enhance the performance and safety of nanomedicines used in vivo.

Metal Ion-Directed Functional Metal-Phenolic Materials

Metal ions are ubiquitous in nature and play significant roles in assembling functional materials in fields spanning chemistry, biology, and materials science. Metal-phenolic materials are assembled from phenolic components in the presence of metal ions through the formation of metal-organic complexes. Alkali, alkali-earth, transition, and noble metal ions as well as metalloids interacting with phenolic building blocks have been widely exploited to generate diverse hybrid materials. Despite extensive studies on the synthesis of metal-phenolic materials, a comprehensive summary of how metal ions guide the assembly of phenolic compounds is lacking. A fundamental understanding of the roles of metal ions in metal-phenolic materials engineering will facilitate the assembly of materials with specific and functional properties. In this review, we focus on the diversity and function of metal ions in metal-phenolic material engineering and emerging applications. Specifically, we discuss the range of underlying interactions, including (i) cation-π, (ii) coordination, (iii) redox, and (iv) dynamic covalent interactions, and highlight the wide range of material properties resulting from these interactions. Applications (e.g., biological, catalytic, and environmental) and perspectives of metal-phenolic materials are also highlighted.

Self-Assembly of Oriented Antibody-Decorated Metal-Organic Framework Nanocrystals for Active-Targeting Applications

Antibody (Ab)-targeted nanoparticles are becoming increasingly important for precision medicine. By controlling the Ab orientation, targeting properties can be enhanced; however, to afford such an ordered configuration, cumbersome chemical functionalization protocols are usually required. This aspect limits the progress of Abs-nanoparticles toward nanomedicine translation. Herein, a novel one-step synthesis of oriented monoclonal Ab-decorated metal-organic framework (MOF) nanocrystals is presented. The crystallization of a zinc-based MOF, Zn₂ (mIM)₂ (CO₃ ), from a solution of Zn²⁺ and 2-methylimidazole (mIM), is triggered by the fragment crystallizable (Fc) region of the Ab. This selective growth yields biocomposites with oriented Abs on the MOF nanocrystals (MOF*Ab): the Fc regions are partially inserted within the MOF surface and the antibody-binding regions protrude from the MOF surface toward the target. This ordered configuration imparts antibody-antigen recognition properties to the biocomposite and shows preserved target binding when compared to the parental antibodies. Next, the biosensing performance of the system is tested by loading MOF*Ab with luminescent quantum dots (QD). The targeting efficiency of the QD-containing MOF*Ab is again, fully preserved. The present work represents a simple self-assembly approach for the fabrication of antibody-decorated MOF nanocrystals with broad potential for sensing, diagnostic imaging, and targeted drug delivery.

Nanostructured particles assembled from natural building blocks for advanced therapies

Advanced treatments based on immune system manipulation, gene transcription and regulation, specific organ and cell targeting, and/or photon energy conversion have emerged as promising therapeutic strategies against a range of challenging diseases. Naturally derived macromolecules (e.g., proteins, lipids, polysaccharides, and polyphenols) have increasingly found use as fundamental building blocks for nanostructured particles as their advantageous properties, including biocompatibility, biodegradability, inherent bioactivity, and diverse chemical properties make them suitable for advanced therapeutic applications. This review provides a timely and comprehensive summary of the use of a broad range of natural building blocks in the rapidly developing field of advanced therapeutics with insights specific to nanostructured particles. We focus on an up-to-date overview of the assembly of nanostructured particles using natural building blocks and summarize their key scientific and preclinical milestones for advanced therapies, including adoptive cell therapy, immunotherapy, gene therapy, active targeted drug delivery, photoacoustic therapy and imaging, photothermal therapy, and combinational therapy. A cross-comparison of the advantages and disadvantages of different natural building blocks are highlighted to elucidate the key design principles for such bio-derived nanoparticles toward improving their performance and adoption. Current challenges and future research directions are also discussed, which will accelerate our understanding of designing, engineering, and applying nanostructured particles for advanced therapies.

Macromolecular Engineering of Thermoresponsive Metal-Phenolic Networks

Dynamic nanostructured materials that can react to physical and chemical stimuli have attracted interest in the biomedical and materials science fields. Metal-phenolic networks (MPNs) represent a modular class of such materials: these networks form via coordination of phenolic molecules with metal ions and can be used for surface and particle engineering. To broaden the range of accessible MPN properties, we report the fabrication of thermoresponsive MPN capsules using Fe^III ions and the thermoresponsive phenolic building block biscatechol-functionalized poly(N-isopropylacrylamide) (biscatechol-PNIPAM). The MPN capsules exhibited reversible changes in capsule size and shell thickness in response to temperature changes. The temperature-induced capsule size changes were influenced by the chain length of biscatechol-PNIPAM and catechol-to-Fe^III ion molar ratio. The metal ion type also influenced the capsule size changes, allowing tuning of the MPN capsule mechanical properties. Al^III-based capsules, having a lower stiffness value (10.7 mN m^-1), showed a larger temperature-induced size contraction (∼63%) than Tb^III-based capsules, which exhibit a higher stiffness value (52.6 mN m^-1) and minimal size reduction (<1%). The permeability of the MPN capsules was controlled by changing the temperature (25-50 °C)─a reduced permeability was obtained as the temperature was increased above the lower critical solution temperature of biscatechol-PNIPAM. This temperature-dependent permeability behavior was exploited to encapsulate and release model cargo (500 kDa fluorescein isothiocyanate-tagged dextran) from the capsules; approximately 70% was released over 90 min at 25 °C. This approach provides a synthetic strategy for developing dynamic and thermoresponsive-tunable MPN systems for potential applications in biological science and biotechnology.

Nanoparticle-Enabled Multiplexed Electrochemical Immunoassay for Detection of Surface Proteins on Extracellular Vesicles

Extracellular vesicles (EVs) are lipid bilayer particles secreted from various cells. EVs carry molecular information of parent cells and hold considerable promise for early disease diagnostics. This paper describes a general strategy for multiplexed immunosensing of EV surface proteins, focusing on surface markers CD63, CD81, nephrin, and podocin to prove the concept. This sensing strategy entailed functionalizing gold nanoparticles (AuNPs) with two types of antibodies and then tagging with metal ions, either Pb2+ or Cu2+. The metal ions served as redox reporters, generating unique redox peaks at -0.23 and 0.28 V (vs Ag/AgCl) during electrochemical oxidation of Pb2+ and Cu2+, respectively. Capture of EVs on the working electrode, followed by labeling with immunoprobes and square wave voltammetry, produced redox currents proportional to concentrations of EVs and levels of expression of EV surface markers. Importantly, metal-ion tagging of immunoprobes enabled detection of two EV surface markers simultaneously from the same electrode. We demonstrated dual detection of either CD63/CD81 or podocin/nephrin surface markers from urinary EVs. The NP-enabled immunoassay had a sensitivity of 2.46 × 105 particles/mL (or 40.3 pg/mL) for CD63- and 5.80 × 105 particles/mL (or 47.7 pg/mL) for CD81-expressing EVs and a linear range of four orders of magnitude. The limit of detection for podocin and nephrin was 3.1 and 3.8 pg/mL, respectively. In the future, the capacity for multiplexing may be increased by extending the repertoire of metal ions used for redox tagging of AuNPs.

Facile Polyphenol-Europium Assembly Enabled Functional Poly(l-Lactic Acid) Nanofiber Mats with Enhanced Antioxidation and Angiogenesis for Accelerated Wound Healing

Burns, trauma, surgery and chronic diabetic ulcers are the most common reasons causing skin wounds in clinic. Thus, developing a functional wound dressing has been an imperative issue. Herein, functional wound dressing (poly(l-lactic acid) PLLA-((tanic acid (TA)/europium (Eu))_n ) is fabricated through a facile polyphenol-europium ion assembly to ameliorate wound microenvironment via scavenging excessive reactive oxygen species (ROS) and promoting angiogenesis. The physicochemical characterization indicates that the multicycle assembled TA/Eu is uniformly deposited on PLLA-(TA/Eu)_n nanofiber mats surface. In vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant tests display good antioxidant ability by scavenging more than 75% ROS, and significantly increasing the antioxidant enzyme levels in vivo. Cytocompatibility experiments illustrate that PLLA-(TA/Eu)_n nanofiber mats can promote the adhesion and proliferation of human umbilical vein endothelial cells (HUVECs) and L929 cells. Meanwhile, real-time quantitative polymerase chain reaction (PCR) (RT-qPCR) and western blot assays illustrate that it can stimulate proangiogenesis by elevating the expression of angiogenesis-related genes and proteins. In vivo Sprague-Dawley (SD) rats experiments indicate that PLLA-(TA/Eu)_n nanofiber mats can significantly promote wound healing by improving both angiogenesis and antioxidant activity. Taken together, the functional PLLA-(TA/Eu)_n nanofiber mats can offer significant promise as wound dressing for accelerated wound healing.

Systematic Comparison of the Structural and Dynamic Properties of Commonly Used Water Models for Molecular Dynamics Simulations

Water is a unique solvent that is ubiquitous in biology and present in a variety of solutions, mixtures, and materials settings. It therefore forms the basis for all molecular dynamics simulations of biological phenomena, as well as for many chemical, industrial, and materials investigations. Over the years, many water models have been developed, and it remains a challenge to find a single water model that accurately reproduces all experimental properties of water simultaneously. Here, we report a comprehensive comparison of structural and dynamic properties of 30 commonly used 3-point, 4-point, 5-point, and polarizable water models simulated using consistent settings and analysis methods. For the properties of density, coordination number, surface tension, dielectric constant, self-diffusion coefficient, and solvation free energy of methane, models published within the past two decades consistently show better agreement with experimental values compared to models published earlier, albeit with some notable exceptions. However, no single model reproduced all experimental values exactly, highlighting the need to carefully choose a water model for a particular study, depending on the phenomena of interest. Finally, machine learning algorithms quantified the relationship between the water model force field parameters and the resulting bulk properties, providing insight into the parameter-property relationship and illustrating the challenges of developing a water model that can accurately reproduce all properties of water simultaneously.

Hydrazide-assisted directional antibody conjugation of gold nanoparticles to enhance immunochromatographic assay

The analytical performance of immunochromatographic assay (ICA) is usually determined by the biological activity of antibody and gold nanoparticle conjugates (AuNP probes). However, conventional probes are constructed using the nondirectional coupling method that can cause the improper orientation of antibodies with the poor accessibility of antigen-binding sites. To address these issues, we report a site-specific directional coupling strategy to enhance the bioactivity of AuNP probes through the specific covalent binding of the aldehyde group in the Fc domain of antibodies with the hydrazide group modified on the surface of AuNPs. Through this design, the antibodies can be erected on the AuNP surface to fully expose the Fab domain and achieve the maximized functional availability. Leveraging these AuNP probes as ICA labels, we demonstrate an improved detection of the hepatitis B surface antigen with less used amount of labeled antibody (0.2 mg/pmol AuNPs), shorter reaction time (10 min), better antibody bioactivity, and higher detection sensitivity (2 ng/mL) compared with the carbodiimide method. Overall, this work provides great promise for the design and the construction of high-performance probes to enhance the detection performance of ICA sensors.

Antipathogenic properties and applications of low-dimensional materials

A major health concern of the 21st century is the rise of multi-drug resistant pathogenic microbial species. Recent technological advancements have led to considerable opportunities for low-dimensional materials (LDMs) as potential next-generation antimicrobials. LDMs have demonstrated antimicrobial behaviour towards a variety of pathogenic bacterial and fungal cells, due to their unique physicochemical properties. This review provides a critical assessment of current LDMs that have exhibited antimicrobial behaviour and their mechanism of action. Future design considerations and constraints in deploying LDMs for antimicrobial applications are discussed. It is envisioned that this review will guide future design parameters for LDM-based antimicrobial applications.

Nanomeshes with Sub-10 nm Pores by Glycerol-Triggered 2D Assembly in Liquid Phases for Fast and Selective Membranes

Nanomeshes having ultrathin thicknesses and penetrating nanopores promise fast diffusion and precise selectivity and are highly desired in diffusion-involved processes such as separation. Herein, we report a liquid-phase two-dimensional (2D) assembly strategy to synthesize phenolic and carbonaceous nanomeshes with sub-10 nm pores and thicknesses. The synthesis is enabled simply by introducing glycerol in the thermopolymerization of resol/polyether micelles dispersed in ethanol. Experimental and simulation results reveal that glycerol's strong ability to form hydrogen bonds constrain the motion of the micelles, directing them to pack and merge exclusively in the lateral direction. Upon removal of polyether, we obtain phenolic nanomeshes with lateral sizes up to hundreds of micrometers, which can be further converted to carbonaceous nanomeshes. As a proof of concept, we use stacked phenolic and carbonaceous nanomeshes as separation membranes. They show superior permselectivity to nanosized solutes with permeance ∼2-110 times higher than that of other membranes.

Phenolic-enabled nanotechnology: versatile particle engineering for biomedicine

Phenolics are ubiquitous in nature and have gained immense research attention because of their unique physiochemical properties and widespread industrial use. In recent decades, their accessibility, versatile reactivity, and relative biocompatibility have catalysed research in phenolic-enabled nanotechnology (PEN) particularly for biomedical applications which have been a major benefactor of this emergence, as largely demonstrated by polydopamine and polyphenols. Therefore, it is imperative to overveiw the fundamental mechanisms and synthetic strategies of PEN for state-of-the-art biomedical applications and provide a timely and comprehensive summary. In this review, we will focus on the principles and strategies involved in PEN and summarize the use of the PEN synthetic toolkit for particle engineering and the bottom-up synthesis of nanohybrid materials. Specifically, we will discuss the attractive forces between phenolics and complementary structural motifs in confined particle systems to synthesize high-quality products with controllable size, shape, composition, as well as surface chemistry and function. Additionally, phenolic's numerous applications in biosensing, bioimaging, and disease treatment will be highlighted. This review aims to provide guidelines for new scientists in the field and serve as an up-to-date compilation of what has been achieved in this area, while offering expert perspectives on PEN's use in translational research.

Artificial Bioaugmentation of Biomacromolecules and Living Organisms for Biomedical Applications

The synergistic union of nanomaterials with biomaterials has revolutionized synthetic chemistry, enabling the creation of nanomaterial-based biohybrids with distinct properties for biomedical applications. This class of materials has drawn significant scientific interest from the perspective of functional extension via controllable coupling of synthetic and biomaterial components, resulting in enhancement of the chemical, physical, and biological properties of the obtained biohybrids. In this review, we highlight the forefront materials for the combination with biomacromolecules and living organisms and their advantageous properties as well as recent advances in the rational design and synthesis of artificial biohybrids. We further illustrate the incredible diversity of biomedical applications stemming from artificially bioaugmented characteristics of the nanomaterial-based biohybrids. Eventually, we aim to inspire scientists with the application horizons of the exciting field of synthetic augmented biohybrids.

Metal-phenolic networks for cancer theranostics

Metal-phenolic networks (MPNs) have shown promising potential in biomedical applications since they provide a rapid, simple and robust way to construct multifunctional nanoplatforms. As a novel nanomaterial self-assembled from metal ions and polyphenols, MPNs can be prepared to assist the theranostics of cancer owing to their bio-adhesiveness, good biocompatibility, versatile drug loading, and stimuli-responsive profile. This Critical Review aims to summarize recent progress in MPN-based nanoplatforms for multimodal tumor therapy and imaging. First, the advantages of MPNs as drug carriers are summarized. Then, various tumor therapeutic modalities based on MPNs are introduced. Next, MPN-based theranostic systems are reviewed. In terms of in vivo applications, specific attention is paid to their biosafety, biodistribution, as well as excretion. Finally, some problems and limitations of MPNs are discussed, along with a future perspective on the field.

Hybrid Metal-Phenol Nanoparticles with Polydopamine-like Coating for PET/SPECT/CT Imaging

The validation of metal-phenolic nanoparticles (MPNs) in preclinical imaging studies represents a growing field of interest due to their versatility in forming predesigned structures with unique properties. Before MPNs can be used in medicine, their pharmacokinetics must be optimized so that accumulation in nontargeted organs is prevented and toxicity is minimized. Here, we report the fabrication of MPNs made of a coordination polymer core that combines In(III), Cu(II), and a mixture of the imidazole 1,4-bis(imidazole-1-ylmethyl)-benzene and the catechol 3,4-dihydroxycinnamic acid ligands. Furthermore, a phenolic-based coating was used as an anchoring platform to attach poly(ethylene glycol) (PEG). The resulting MPNs, with effective hydrodynamic diameters of around 120 nm, could be further derivatized with surface-embedded molecules, such as folic acid, to facilitate in vivo targeting and multifunctionality. The prepared MPNs were evaluated for in vitro plasma stability, cytotoxicity, and cell internalization and found to be biocompatible under physiological conditions. First, biomedical evaluations were then performed by intrinsically incorporating trace amounts of the radioactive metals 111In or 64Cu during the MPN synthesis directly into their polymeric matrix. The resulting particles, which had identical physicochemical properties to their nonradioactive counterparts, were used to perform in vivo single-photon emission computed tomography (SPECT) and positron emission tomography (PET) in tumor-bearing mice. The ability to incorporate multiple metals and radiometals into MPNs illustrates the diverse range of functional nanoparticles that can be prepared with this approach and broadens the scope of these nanoconstructs as multimodal preclinical imaging agents.

Not only in silico drug discovery: Molecular modeling towards in silico drug delivery formulations

The use of methods at molecular scale for the discovery of new potential active ligands, as well as previously unknown binding sites for target proteins, is now an established reality. Literature offers many successful stories of active compounds developed starting from insights obtained in silico and approved by Food and Drug Administration (FDA). One of the most famous examples is raltegravir, a HIV integrase inhibitor, which was developed after the discovery of a previously unknown transient binding area thanks to molecular dynamics simulations. Molecular simulations have the potential to also improve the design and engineering of drug delivery devices, which are still largely based on fundamental conservation equations. Although they can highlight the dominant release mechanism and quantitatively link the release rate to design parameters (size, drug loading, et cetera), their spatial resolution does not allow to fully capture how phenomena at molecular scale influence system behavior. In this scenario, the "computational microscope" offered by simulations at atomic scale can shed light on the impact of molecular interactions on crucial parameters such as release rate and the response of the drug delivery device to external stimuli, providing insights that are difficult or impossible to obtain experimentally. Moreover, the new paradigm brought by nanomedicine further underlined the importance of such computational microscope to study the interactions between nanoparticles and biological components with an unprecedented level of detail. Such knowledge is a fundamental pillar to perform device engineering and to achieve efficient and safe formulations. After a brief theoretical background, this review aims at discussing the potential of molecular simulations for the rational design of drug delivery systems.

Polyvalent Biotinylated Aptamer Scaffold for Rapid and Sensitive Detection of Tau Proteins

Biomimetic construction of artificial scaffolds has attracted increasing attention. However, the construction methods usually require redundant materials and procedures, which is inconvenient for further application. Herein, inspired by the polyvalent multifunctional structure in nature, we have designed a polyvalent biotinylated aptamer scaffold (PBAS) which can conduct analytical performance with high sensitivity and simplified procedures. To construct a PBAS, the aptamers are designed to hybridize with prepared linker probes to form polyvalent biotinylated scaffolds, which contain both multiple aptamers and signal labels. Therefore, multifunctional scaffolds can be constructed with high recognition and capture efficiency as well as significant signal amplification. Furthermore, the scaffold can be used for the assay of some disease marker proteins. By taking tau proteins as an example, the proposed aptasensor can exhibit excellent performance with a low detection limit of 153 pg mL^-1 and a short assay time of 50 min, which is much better than most of the previous methods. By assays of tau proteins in both serum and artificial cerebro spinal fluid, the PBAS-based aptasensor can work well. Therefore, the scaffold may be expected to be a powerful analytical tool which may have wide applications in the detection of a variety of analytes.

Medical Applications Based on Supramolecular Self-Assembled Materials From Tannic Acid

Polyphenol, characterized by various phenolic rings in the chemical structure and an abundance in nature, can be extracted from vegetables, grains, chocolates, fruits, tea, legumes, and seeds, among other sources. Tannic acid (TA), a classical polyphenol with a specific chemical structure, has been widely used in biomedicine because of its outstanding biocompatibility and antibacterial and antioxidant properties. TA has tunable interactions with various materials that are widely distributed in the body, such as proteins, polysaccharides, and glycoproteins, through multimodes including hydrogen bonding, hydrophobic interactions, and charge interactions, assisting TA as important building blocks in the supramolecular self-assembled materials. This review summarizes the recent immense progress in supramolecular self-assembled materials using TA as building blocks to generate different materials such as hydrogels, nanoparticles/microparticles, hollow capsules, and coating films, with enormous potential medical applications including drug delivery, tumor diagnosis and treatment, bone tissue engineering, biofunctional membrane material, and the treatment of certain diseases. Furthermore, we discuss the challenges and developmental prospects of supramolecular self-assembly nanomaterials based on TA.