Supramolecular Polyphenol-DNA Microparticles for In Vivo Adjuvant and Antigen Co-Delivery and Immune Stimulation

Polyphenol Mediated Assembly: Tailored Nano-Dredger Unblocks Axonal Autophagosomes Retrograde Transport Traffic Jam for Accelerated Alzheimer's Waste Clearance

Clear-cut evidence has linked defective autophagy to Alzheimer's disease (AD). Recent studies underscore a unique hurdle in AD neuronal autophagy: impaired retrograde axonal transport of autophagosomes, potent enough to induce autophagic stress and neurodegeneration. Nonetheless, pertinent therapy is unavailable. Here, a novel combinational therapy composed of siROCK2 and lithospermic acid B (LA) is introduced, tailored to dredge blocked axonal autophagy by multi-mitigating microtubule disruption, ATP depletion, oxidative stress, and autophagy initiation impediments in AD. Leveraging the recent discovery of multi-interactions between polyphenol LA and siRNA, ε-Poly-L-lysine, and anionic lipid nanovacuoles, LA and siROCK2 are successfully co-loaded into a fresh nano-drug delivery system, LIP@PL-LA/siRC, via a ratio-flexible and straightforward fabrication process. Further modification with the TPL peptide onto LIP@PL-LA/siRC creates a brain-neuron targeted, biocompatible, and pluripotent nanomedicine, named "Nano-dredger" (T-LIP@PL-LA/siRC). Nano-dredger efficiently accelerates axonal retrograde transport and lysosomal degradation of autophagosomes, thereby facilitating the clearance of neurotoxic proteins, improving neuronal complexity, and alleviating memory defects in 3×Tg-AD transgenic mice. This study provides a fresh and flexible polyphenol/siRNA co-delivery paradigm and furnishes conceptual proof that dredging axonal autophagy represents a promising AD therapeutic avenue.

Nanomaterial-assisted delivery of CpG oligodeoxynucleotides for boosting cancer immunotherapy

Cancer immunotherapy aims to improve immunity to not only eliminate the primary tumor but also inhibit metastasis and recurrence. It is considered an extremely promising therapeutic approach that breaks free from the traditional paradigm of oncological treatment. As the medical community learns more about the immune system's mechanisms that "turn off the brake" and "step on the throttle", there is increasingly successful research on immunomodulators. However, there are still more restrictions than countermeasures with immunotherapy related to immunomodulators, such as low responsiveness and immune-related adverse events that cause multiple adverse reactions. Therefore, medical experts and materials scientists attempted to the efficacy of immunomodulatory treatments through various methods, especially nanomaterial-assisted strategies. CpG oligodeoxynucleotides (CpG) not only act as an adjuvant to promote immune responses, but also induce autophagy. In this review, the enhancement of immunotherapy using nanomaterial-based CpG formulations is systematically elaborated, with a focus on the delivery, protection, synergistic promotion of CpG efficacy by nanomaterials, and selection of the timing of treatment. In addition, we also discuss and prospect the existing problems and future directions of research on nanomaterials in auxiliary CpG therapy.

Spatial Engineering of Heterotypic Antigens on a DNA Framework for the Preparation of Mosaic Nanoparticle Vaccines with Enhanced Immune Activation against SARS-CoV-2 Variants

Mosaic nanoparticle vaccines with heterotypic antigens exhibit broad-spectrum antiviral capabilities, but the impact of antigen proportions and distribution patterns on vaccine-induced immunity remains largely unexplored. Here, we present a DNA nanotechnology-based strategy for spatially assembling heterotypic antigens to guide the rational design of mosaic nanoparticle vaccines. By utilizing two aptamers with orthogonal selectivity for the original SARS-CoV-2 spike trimer and Omicron receptor-binding domain (RBD), along with a DNA soccer-ball framework, we precisely manipulate the spacing, stoichiometry, and overall distribution of heterotypic antigens to create mosaic nanoparticles with average, bipolar, and unipolar antigen distributions. Systematic in vitro and in vivo immunological investigations demonstrate that 30 heterotypic antigens in equivalent proportions, with an average distribution, lead to higher production of broad-spectrum neutralizing antibodies compared to the bipolar and unipolar distributions. Furthermore, the precise assembly utilizing our developed methodology reveals that a mere increment of five Omicron RBD antigens on a nanoparticle (from 15 to 20) not only diminishes neutralization against the Omicron variant but also triggers excessive inflammation. This work provides a unique perspective on the rational design of mosaic vaccines by highlighting the significance of the spatial placement and proportion of heterotypic antigens in their structure-activity mechanisms.

Tannic Acid-Enabled Antioxidant and Stretchable MXene/Silk Strain Sensors for Diving Training Healthcare

MXene-based conductive hydrogels hold significant promise as epidermal sensors, yet their susceptibility to oxidation represents a formidable limitation. This study addresses this challenge by incorporating MXene into a tannic acid (TA) cross-linked silk fibroin matrix. The resulting conductive hydrogel (denoted as e-dive) exhibits favorable characteristics such as adjustable mechanical properties, self-healing capabilities (both mechanically and electrically), and strong underwater adhesion. The existence of a percolation network of MXene within the nanocomposites guarantees good electrical conductivity. Importantly, the surface interaction of MXene nanosheets with the hydrophobic moiety from TA substantially reduced moisture and oxygen interactions with MXene, thereby effectively mitigating MXene oxidation within hydrogel matrices. This preservation of the electrical characteristics ensures prolonged functional stability. Furthermore, the e-dive demonstrates inherent antibacterial properties, making it suitable for use in underwater environments where bacterial contamination is a concern. The utilization of this advanced e-dive system extends to the correction of diving postures and the facilitation of underwater healthcare and security alerts. Our study presents a robust methodology for enhancing the stability of MXene-based conductive hydrogel electronics, thereby expanding their scope of potential applications.

Phenolic-enabled nanotechnology: a new strategy for central nervous system disease therapy

Polyphenolic compounds have received tremendous attention in biomedicine because of their good biocompatibility and unique physicochemical properties. In recent years, phenolic-enabled nanotechnology (PEN) has become a hotspot of research in the medical field, and many promising studies have been reported, especially in the application of central nervous system (CNS) diseases. Polyphenolic compounds have superior anti-inflammatory and antioxidant properties, and can easily cross the blood‒brain barrier, as well as protect the nervous system from metabolic damage and promote learning and cognitive functions. However, although great advances have been made in this field, a comprehensive review regarding PEN-based nanomaterials for CNS therapy is lacking. A systematic summary of the basic mechanisms and synthetic strategies of PEN-based nanomaterials is beneficial for meeting the demand for the further development of novel treatments for CNS diseases. This review systematically introduces the fundamental physicochemical properties of PEN-based nanomaterials and their applications in the treatment of CNS diseases. We first describe the different ways in which polyphenols interact with other substances to form high-quality products with controlled sizes, shapes, compositions, and surface chemistry and functions. The application of PEN-based nanomaterials in the treatment of CNS diseases is then described, which provides a reference for subsequent research on the treatment of CNS diseases.

An Antibiotic Nanobomb Constructed from pH-Responsive Chemical Bonds in Metal-Phenolic Network Nanoparticles for Biofilm Eradication and Corneal Ulcer Healing

In the treatment of refractory corneal ulcers caused by Pseudomonas aeruginosa, antibacterial drugs delivery faces the drawbacks of low permeability and short ocular surface retention time. Hence, novel positively-charged modular nanoparticles (NPs) are developed to load tobramycin (TOB) through a one-step self-assembly method based on metal-phenolic network and Schiff base reaction using 3,4,5-trihydroxybenzaldehyde (THBA), ε-poly-ʟ-lysine (EPL), and Cu2+ as matrix components. In vitro antibacterial test demonstrates that THBA-Cu-TOB NPs exhibit efficient instantaneous sterilization owing to the rapid pH responsiveness to bacterial infections. Notably, only 2.6 µg mL-1 TOP is needed to eradicate P. aeruginosa biofilm in the nano-formed THBA-Cu-TOB owing to the greatly enhanced penetration, which is only 1.6% the concentration of free TOB (160 µg mL-1). In animal experiments, THBA-Cu-TOB NPs show significant advantages in ocular surface retention, corneal permeability, rapid sterilization, and inflammation elimination. Based on molecular biology analysis, the toll-like receptor 4 and nuclear factor kappa B signaling pathways are greatly downregulated as well as the reduction of inflammatory cytokines secretions. Such a simple and modular strategy in constructing nano-drug delivery platform offers a new idea for toxicity reduction, physiological barrier penetration, and intelligent drug delivery.

Boosting humoral and cellular immunity with enhanced STING activation by hierarchical mesoporous metal-organic framework adjuvants

Vaccination is essential for preventing and controlling infectious diseases, along with reducing mortality. Developing safe and versatile adjuvants to enhance humoral and cellular immune responses to vaccines remains a key challenge in vaccine development. Here, we designed hierarchical mesoporous MOF-801 (HM801) using a Cocamidopropyl betaine (CAPB) and a Pluronics F127 in an aqueous phase system. Meanwhile, we synthesized a novel SARS-CoV-2 nanovaccine (R@M@HM801) with a high loading capacity for both the STING agonist (MSA-2) and the Delta receptor binding domain (Delta-RBD) antigen. R@M@HM801 enhanced MSA-2 and RBD utilization and effectively co-delivered MSA-2 and RBD antigens to antigen-presenting cells in the draining lymph nodes, thereby promoting the activation of both T and B cells. Lymphocyte single-cell analysis showed that R@M@HM801 stimulated robust CD11b+CD4+ T cells, CXCR5+CD4+ T follicular helper (Tfh), and durable CD4+CD44+CD62L-, CD8+CD44+CD62L- effector memory T cell (TEM) immune responses, and promoted the proliferative activation of CD26+ B cells in vivo. Meanwhile, R@M@HM801 induced stronger specific antibodies and neutralization of pseudovirus against Delta compared to the RBD + MAS-2 and RBD + MAS-2 + Alum vaccines. Our study demonstrated the efficacy of a hierarchical mesoporous HM801 and its potential immune activation mechanism in enhancing adaptive immune responses against viruses and other diseases.

Polyphenolic Nanoparticle Platforms (PARCELs) for In Vitro and In Vivo mRNA Delivery

Despite their successful implementation in the COVID-19 vaccines, lipid nanoparticles (LNPs) still face a central limitation in the delivery of mRNA payloads: endosomal trapping. Improving upon this inefficiency could afford improved drug delivery systems, paving the way toward safer and more effective mRNA-based medicines. Here, we present polyphenolic nanoparticle platforms (PARCELs) as effective mRNA delivery systems. In brief, our investigation begins with a computationally guided structural analysis of 1825 discrete polyphenolic structural data points across 73 diverse small molecule polyphenols and 25 molecular parameters. We then generate structurally diverse PARCELs, evaluating their in vitro mechanism and activity, ultimately highlighting the superior endosomal escape properties of PARCELs relative to analogous LNPs. Finally, we examine the in vivo biodistribution, protein expression, and therapeutic efficacy of PARCELs in mice. In undertaking this approach, the goal of this study is to establish PARCELs as viable delivery platforms for safe and effective mRNA delivery.

Controlled Self-Assembly of Natural Polyphenols Driven by Multiple Molecular Interactions

Nature has exhibited a high degree of control over the structures and functions. Supramolecules have been utilized to mimic the subtle assembly in nature. However, sophisticated synthesis of molecular skeletons or programmable design of the driving forces raises great challenges in fabricating high-level superstructures in a controlled manner. Natural polyphenols show great promises as building blocks for a diverse of assemblies with controlled structures and functionalities. The intrinsically embedded phenolic groups (i. e., catechol and galloyl groups) are readily forming multiple molecular interactions, including coordination, hydrogen bonding, and π-π interactions with various materials of inorganic particles, organic compounds, synthetic polymers, and biomacromolecules, providing the self-assembled structures or nanocoating on surfaces. Subsequent assembly occurred by further bonding of polyphenols to construct supraparticles. To gain control over the self-assembly, the key lies in the interplay among the molecular interactions with one or two being dominant. In this Perspective, we introduce the representative polyphenol-based assemblies and their derived supraparticles to exhibit the effective harness of the controlled self-assembly by polyphenols.

Emerging nanoparticle platforms for CpG oligonucleotide delivery

Unmethylated cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (ODNs), which were therapeutic DNA with high immunostimulatory activity, have been applied in widespread applications from basic research to clinics as therapeutic agents for cancer immunotherapy, viral infection, allergic diseases and asthma since their discovery in 1995. The major factors to consider for clinical translation using CpG motifs are the protection of CpG ODNs from DNase degradation and the delivery of CpG ODNs to the Toll-like receptor-9 expressed human B-cells and plasmacytoid dendritic cells. Therefore, great efforts have been devoted to the advances of efficient delivery systems for CpG ODNs. In this review, we outline new horizons and recent developments in this field, providing a comprehensive summary of the nanoparticle-based CpG delivery systems developed to improve the efficacy of CpG-mediated immune responses, including DNA nanostructures, inorganic nanoparticles, polymer nanoparticles, metal-organic-frameworks, lipid-based nanosystems, proteins and peptides, as well as exosomes and cell membrane nanoparticles. Moreover, future challenges in the establishment of CpG delivery systems for immunotherapeutic applications are discussed. We expect that the continuously growing interest in the development of CpG-based immunotherapy will certainly fuel the excitement and stimulation in medicine research.

Engineering poly(ethylene glycol) particles for targeted drug delivery

Poly(ethylene glycol) (PEG) is considered to be the "gold standard" among the stealth polymers employed for drug delivery. Using PEG to modify or engineer particles has thus gained increasing interest because of the ability to prolong blood circulation time and reduce nonspecific biodistribution of particles in vivo, owing to the low fouling and stealth properties of PEG. In addition, endowing PEG-based particles with targeting and drug-loading properties is essential to achieve enhanced drug accumulation at target sites in vivo. In this feature article, we focus on recent work on the synthesis of PEG particles, in which PEG is the main component in the particles. We highlight different synthesis methods used to generate PEG particles, the influence of the physiochemical properties of PEG particles on their stealth and targeting properties, and the application of PEG particles in targeted drug delivery.

Natural polyphenols for drug delivery and tissue engineering construction: A review

Polyphenols, natural compounds rich in phenolic structures, are gaining prominence due to their antioxidant, anti-inflammatory, antibacterial, and anticancer properties, making them valuable in biomedical applications. Through covalent and noncovalent interactions, polyphenols can bind to biomaterials, enhancing their performance and compensating for their shortcomings. Such polyphenol-based biomaterials not only increase the efficacy of polyphenols but also improve drug stability, control release kinetics, and boost the therapeutic effects of drugs. They offer the potential for targeted drug delivery, reducing off-target impacts and enhancing therapeutic outcomes. In tissue engineering, polyphenols promote cell adhesion, proliferation, and differentiation, thus aiding in the formation of functional tissues. Additionally, they offer excellent biocompatibility and mechanical strength, essential in designing scaffolds. This review explores the significant roles of polyphenols in tissue engineering and drug delivery, emphasizing their potential in advancing biomedical research and healthcare.

Supramolecular self-assembly of EGCG-selenomethionine nanodrug for treating osteoarthritis

Osteoarthritis (OA) has emerged as a significant health concern among the elderly population, with increasing attention paid to ferroptosis-induced OA in recent years. However, the prolonged use of nonsteroidal anti-inflammatory drugs or corticosteroids can lead to a series of side effects and limited therapeutic efficacy. This study aimed to employ the Mannich condensation reaction between epigallocatechin-3-gallate (EGCG) and selenomethionine (SeMet) to efficiently synthesize polyphenol-based nanodrugs in aqueous media for treating OA. Molecular biology experiments demonstrated that EGCG-based nanodrugs (ES NDs) could effectively reduce glutathione peroxidase 4 (GPX4) inactivation, abnormal Fe2+ accumulation, and lipid peroxidation induced by oxidative stress, which ameliorated the metabolic disorder of chondrocytes and other multiple pathological processes triggered by ferroptosis. Moreover, imaging and histopathological analysis of the destabilization of the medial meniscus model in mice confirmed that ES NDs exhibiting significant therapeutic effects in relieving OA. The intra-articular delivery of ES NDs represents a promising approach for treating OA and other joint inflammatory diseases.

Harnessing biomaterial architecture to drive anticancer innate immunity

Immunomodulation is a powerful therapeutic approach that harnesses the body's own immune system and reprograms it to treat diseases, such as cancer. Innate immunity is key in mobilizing the rest of the immune system to respond to disease and is thus an attractive target for immunomodulation. Biomaterials have widely been employed as vehicles to deliver immunomodulatory therapeutic cargo to immune cells and raise robust antitumor immunity. However, it is key to consider the design of biomaterial chemical and physical structure, as it has direct impacts on innate immune activation and antigen presentation to stimulate downstream adaptive immunity. Herein, we highlight the widespread importance of structure-driven biomaterial design for the delivery of immunomodulatory cargo to innate immune cells. The incorporation of precise structural elements can be harnessed to improve delivery kinetics, uptake, and the targeting of biomaterials into innate immune cells, and enhance immune activation against cancer through temporal and spatial processing of cargo to overcome the immunosuppressive tumor microenvironment. Structural design of immunomodulatory biomaterials will profoundly improve the efficacy of current cancer immunotherapies by maximizing the impact of the innate immune system and thus has far-reaching translational potential against other diseases.

Tannic acid-based sustained-release system for protein drugs

In recent years, protein drug development has gained momentum, and simple and facile controlled-release systems without loss of activity are required. Herein, we developed a sustained-release system for protein drugs by exploiting the "astringency" mechanism, namely insoluble precipitate formation by interacting with tannic acid. Tannic acid formed insoluble precipitates with various protein drugs, such as nisin, insulin, lysozyme, ovalbumin, hyaluronidase, and human immunoglobulin G, through hydrophobic interactions and hydrogen bonds. The lysozyme/tannic acid complex retained in vitro lytic activity. Precipitates of the insulin/tannic acid complex prolonged hypoglycemic effects without loss of activity after subcutaneous administration. The ovalbumin/tannic acid complex enhanced anti-ovalbumin antibody production induced by ovalbumin, which may be attributed to its sustained-release profile. Accordingly, tannic acid is useful as a simple and user-friendly drug delivery system for protein drugs.