Nanogels designed for cell-free nucleic acid sequestration

Inflammation-Responsive Polyion Complex Vesicles for Autoimmune Disease Therapy via Cell-Free DNA Scavenging and Inflammatory Microenvironment Modulation

Cell-free DNA (cfDNA) scavenging represents a promising anti-inflammatory modality for autoimmune disease (AID) treatment. However, it remains challenging for existing systems to achieve inflammation-targeted cfDNA scavenging and the management of cfDNA-unrelated inflammatory pathways. Herein, inflammation-responsive polyion complex vesicles (PICsomes) are developed, bridging inflammation-instructed cfDNA scavenging, and methotrexate (MTX) delivery for AID management. A positively charged, PEGylated polypeptide with guanidine side chains (PEG-PG) is developed, which self-assembles with a negatively charged, cis-aconitic anhydride-modified poly-L-lysine (PC) to form the PICsomes and encapsulate MTX disodium salt. The neutrally charged PICsomes feature prolonged blood circulation after systemic administration, allowing for passive accumulation to the inflamed tissues. In the slightly acidic inflammatory microenvironment, PC transforms from negatively charged to positively charged, thereby disintegrating the PICsomes and liberating the PEG-PG and MTX. Consequently, PEG-PG-mediated cfDNA scavenging and MTX-mediated immunosuppression cooperate to inhibit inflammation and ameliorate the inflammatory microenvironment, promoting tissue repair in AID mouse models including collagen-induced arthritis and 2,4,6-trinitrobenzenesulfonic acid-induced colitis.

Nanotechnology-Mediated Immunomodulation Strategy for Inflammation Resolution

Inflammation serves as a common characteristic across a wide range of diseases and plays a vital role in maintaining homeostasis. Inflammation can lead to tissue damage and the onset of inflammatory diseases. Although significant progress is made in anti-inflammation in recent years, the current clinical approaches mainly rely on the systemic administration of corticosteroids and antibiotics, which only provide short-term relief. Recently, immunomodulatory approaches have emerged as promising strategies for facilitating the resolution of inflammation. Especially, the advanced nanosystems with unique biocompatibility and multifunctionality have provided an ideal platform for immunomodulation. In this review, the pathophysiology of inflammation and current therapeutic strategies are summarized. It is mainly focused on the nanomedicines that modulate the inflammatory signaling pathways, inflammatory cells, oxidative stress, and inflammation targeting. Finally, the challenges and opportunities of nanomaterials in addressing inflammation are also discussed. The nanotechnology-mediated immunomodulation will open a new treatment strategy for inflammation therapy.

Colloidal Hydrogel with Staged Sequestration and Release of Molecules Undergoing Competitive Binding

Competitive binding of distinct molecules in the hydrogel interior can facilitate dynamic exchange between the hydrogel and the surrounding environment. The ability to control the rates of sequestration and release of these molecules would enhance the hydrogel's functionality and enable targeting of a specific task. Here, we report the design of a colloidal hydrogel with two distinct pore dimensions to achieve staged, diffusion-controlled scavenging and release dynamics of molecules undergoing competitive binding. The staged scavenging and release strategy was shown for CpG oligodeoxynucleotide (ODN) and human epidermal growth factor (hEGF), two molecules exhibiting different affinities to the quaternary ammonium groups of the hydrogel. Fast ODN scavenging from the ambient environment occurred via diffusion through submicrometer-size hydrogel pores, while delayed hEGF release from the hydrogel was governed by its diffusion through nanometer-size pores. The results of the experiments were in agreement with simulation results. The significance of staged ODN-hEGF exchange was highlighted by the dual anti-inflammation and tissue proliferation hydrogel performance.

Capture and Storage of Cell-Free DNA via Bio-Informational Hydrogel Microspheres

Excessive cell-free DNA (cfDNA) can induce chronic inflammation by activating intracellular nucleic acid sensors. Intervention in cfDNA-mediated "pro-inflammatory signaling transduction" could be a potential alleviating strategy for chronic inflammation, such as in diabetic wounds. However, effectively and specifically downgrading cfDNA concentration in the pathological microenvironment remains a challenge. Therefore, this work prepares free-standing polydopamine nanosheets through DNA-guided assembly and loaded them into microfluidic hydrogel microspheres. The π─π stacking/hydrogen bonding interactions between polydopamine nanosheets and the π-rich bases of cfDNA, along with the cage-like spatial confinement created by the hydrogel polymer network, achieved cfDNA capture and storage, respectively. Catechol in polydopamine nanosheets can also assist in reducing reactive oxygen species (ROS) levels. Efficient cfDNA binding independent of serum proteins, specific interdiction of abnormal activation of cfDNA-associated toll-like receptor 9, as well as down-regulation of inflammatory cytokines and ROS levels are shown in this system. The chronic inflammation alleviating and the pro-healing effects on the mice model with diabetic wounds are also investigated. This work presents a new strategy for capturing and storing cfDNA to intervene in cell signaling transduction. It also offers new insights into the regulatory mechanisms between inflammatory mediators and biomaterials in inflammation-related diseases.

Effects of Different Surface Functionalizations of Silica Nanoparticles on Mesenchymal Stem Cells

Physicochemical properties of nanoparticles, such as particle size, surface charge, and particle shape, have a significant impact on cell activities. However, the effects of surface functionalization of nanoparticles with small chemical groups on stem cell behavior and function remain understudied. Herein, we incorporated different chemical functional groups (amino, DETA, hydroxyl, phosphate, and sulfonate with charges of +9.5, + 21.7, -14.1, -25.6, and -37.7, respectively) to the surface of inorganic silica nanoparticles. To trace their effects on mesenchymal stem cells (MSCs) of rat bone marrow, these functionalized silica nanoparticles were used to encapsulate Rhodamine B fluorophore dye. We found that surface functionalization with positively charged and short-chain chemical groups facilitates cell internalization and retention of nanoparticles in MSCs. The endocytic pathway differed among functionalized nanoparticles when tested with ion-channel inhibitors. Negatively charged nanoparticles mainly use lysosomal exocytosis to exit cells, while positively charged nanoparticles can undergo endosomal escape to avoid scavenging. The cytotoxic profiles of these functionalized silica nanoparticles are still within acceptable limits and tolerable. They exerted subtle effects on the actin cytoskeleton and migration ability. Last, phosphate-functionalized nanoparticles upregulate osteogenesis-related genes and induce osteoblast-like morphology, implying that it can direct MSCs lineage specification for bone tissue engineering. Our study provides insights into the rational design of biomaterials for effective drug delivery and regenerative medicine.

From Nature-Sourced Polysaccharide Particles to Advanced Functional Materials

Polysaccharides constitute over 90% of the carbohydrate mass in nature, which makes them a promising feedstock for manufacturing sustainable materials. Polysaccharide particles (PSPs) are used as effective scavengers, carriers of chemical and biological cargos, and building blocks for the fabrication of macroscopic materials. The biocompatibility and degradability of PSPs are advantageous for their uses as biomaterials with more environmental friendliness. This review highlights the progresses in PSP applications as advanced functional materials, by describing PSP extraction, preparation, and surface functionalization with a variety of functional groups, polymers, nanoparticles, and biologically active species. This review also outlines the fabrication of PSP-derived macroscopic materials, as well as their applications in soft robotics, sensing, scavenging, water harvesting, drug delivery, and bioengineering. The paper is concluded with an outlook providing perspectives in the development and applications of PSP-derived materials.

A review of high internal phase Pickering emulsions: Stabilization, rheology, and 3D printing application

High internal phase Pickering emulsion (HIPPE) is renowned for its exceptionally high-volume fraction of internal phase, leading to flocculated yet deformed emulsion droplets and unique rheological behaviors such as shear-thinning property, viscoelasticity, and thixotropic recovery. Alongside the inherent features of regular emulsion systems, such as large interfacial area and well-mixture of two immiscible liquids, the HIPPEs have been emerging as building blocks to construct three-dimensional (3D) scaffolds with customized structures and programmable functions using an extrusion-based 3D printing technique, making 3D-printed HIPPE-based scaffolds attract widespread interest from various fields such as food science, biotechnology, environmental science, and energy transfer. Herein, the recent advances in preparing suitable HIPPEs as 3D printing inks for various applied fields are reviewed. This work begins with the stabilization mechanism of HIPPEs, followed by introducing the origin of their distinctive rheological behaviors and strategies to adjust the rheological behaviors to prepare more eligible HIPPEs as printing inks. Then, the compatibility between extrusion-based 3D printing and HIPPEs as building blocks was discussed, followed by a summary of the potential applications using 3D-printed HIPPE-based scaffolds. Finally, limitations and future perspectives on preparing HIPPE-based materials using extrusion-based 3D printing were presented.