Fabrication of Multiresponsive Magnetic Nanocomposite Double-Network Hydrogels for Controlled Release Applications

In situ forming an injectable hyaluronic acid hydrogel for drug delivery and synergistic tumor therapy

Stimulus-responsive injectable hydrogel has the key characteristics of in situ drug-loading ability and the controlled drug release, enabling efficient delivery and precise release of chemotherapy drugs at the tumor site, thereby being used as a local drug delivery system for sustained tumor treatment. This article designed a smart responsive injectable hydrogel loaded with anti-tumor drugs and nanoparticles to achieve efficient and specific synergistic treatment of tumors. Hyaluronic acid (HA) hydrogel obtained by cross-linking HA-SH (HS) and HA-Tyr (HT) through horseradish peroxidase (HRP), and doxorubicin hydrochloride (DOX) and folic acid-polyethylene glycol-amine (FA-PEG-NH2) modified PDA (denoted as PPF) were encapsulated to construct the HS/HT@PPF/D hydrogel. The hydrogel had good biocompatibility, injectability, and could respond to multiple stimuli at the tumor site, thereby achieving controlled drug release. At the same time, PPF gave it excellent photothermal efficiency, photothermal stability and tumor targeting. In vitro and in vivo experimental results showed that the HS/HT@PPF/D hydrogel combined with near-infrared laser irradiation could significantly improve its anti-tumor effect and could almost eliminate the entire tumor mass without obvious adverse reactions. The HS/HT@PPF/D hydrogel could achieve multi-stimulus-responsive drug delivery and be used for precise chemo-photothermal synergistic tumor treatment, thus providing a new platform for local synergistic tumor treatment.

Bio‐Inspired Magnetic‐Responsive Supramolecular‐Covalent Semi‐Convertible Hydrogel

Bio-inspired magnetic-responsive hydrogel is confined in exceedingly narrow spaces for soft robots and biomedicine in either gel state or magnetofluidic sol state. However, the motion of the gel state magnetic hydrogel will be inhibited in various irregular spaces due to the fixed shape and size and the sol-state magnetofluid gel may bring unpredictable residues in the confined narrow space. Inspired by the dynamic liquid lubricating mechanism of biological systems, novel magnetic-responsive semi-convertible hydrogel (MSCH) is developed through imbedding magnetic-responsive gelatin and amino-modified Fe3O4 nanoparticles network into the covalent network of polyvinyl alcohol, which can be switched between gel state and gel-sol state in response to magnetic stimuli. It can be attributed the disassembly of triple-helix structures of the gelatin under the action of the magnetic field, driven by force from the magnetic particles conjugated on the gelatin chain through electrostatic interactions, while the covalent network retains the hydrogel structural integrity. This leads to a sol layer on the MSCH surface enabling the MSCH to pass effectively through the confined channel or obstacle under magnetic field. The present MSCH will provide an alternative mode for magnetic field-related soft robots or actuators.

Luminescent lanthanide-containing gelatin/polydextran/laponite nanocomposite double-network hydrogels for processing and sensing applications

Lanthanide-containing nanomaterials have gained significant popularity for their utilization in polymeric networks, enabling the creation of luminescent nanocomposites for advanced applications. In this study, we developed a new type of lanthanide-containing nanocomposite hydrogels by incorporating terbium-containing laponite (Tb3+@Lap) into the networks of polyethyleneimine-modified gelatin/polydextran aldehyde (PG/PDA) through dynamic bonds. The structures and properties of the Tb3+@Lap-containing nanocomposite double-network (ncDN) hydrogels were comprehensively investigated in comparison with the DN hydrogels with a pure polymeric network and the Lap-containing ncDN hydrogels. The PG/PDA/Tb3+@Lap ncDN hydrogels with multiple dynamic bonds (i.e., imine bonds, coordination bonds, hydrogen bonds, and electrostatic interactions) exhibited remarkable characteristics of shear-thinning and self-healing, making them suitable for the construction of hydrogel scaffolds on a macroscale using fabrication techniques such as electrospinning and 3D printing. Moreover, the PG/PDA/Tb3+@Lap ncDN hydrogels have been demonstrated to act as sensitive and selective luminescent sensors for detecting copper ions. Taken together, a versatile lanthanide-containing ncDN hydrogel platform capable of dynamic features is developed for processing and sensing applications.

All-Natural, Robust, and pH-Responsive Glycyrrhizic Acid-Based Double Network Hydrogels for Controlled Nutrient Release

Supramolecular hydrogels self-assembled from naturally occurring small molecules (e.g., glycyrrhizic acid, GA) are promising materials for controlled bioactive delivery due to their facile fabrication processes, excellent biocompatibility, and versatile stimuli-responsive behaviors. However, most of these natural hydrogels suffer from poor mechanical strength and processability for practical applications. In this work, through adopting a multicomponent gel approach, we developed a novel mechanically robust GA-based hydrogel with an interpenetrating double network (DN) that is composed of a Ca2+-enhanced hydrogen-bond supramolecular GA nanofibril (GN) network and a Ca2+cross-linked natural polysaccharide sodium alginate (ALG) network. Compared to the single GN network (SN) hydrogel, the GN-ALG hybrid hydrogels (GN-ALG-DN) with the hierarchical double-network structure possess excellent mechanical properties and shaping adaptation, encouraging small and large amplitude oscillatory shear (SAOS and LAOS) rheological performances, better thermal stability, higher resistance to large compression deformations, and lower swelling behaviors. Furthermore, the GN-ALG-DN hydrogels exhibit a pH-responsive and sustained release behavior of nutrients (i.e., vitamin B12, VB12), showing a faster VB12 release rate with a higher swelling ratio in an alkaline condition (pH 7.5) than in an acidic condition (pH 2.5). This is ascribed to the fact that the higher dissociation degree of carboxylic groups in GA and ALG molecules in an alkaline environment induces the erosion and looseness of the self-assembled GN network and the ionic-cross-linked ALG network, which can lead to the decomposition of the hybrid hydrogels and thereby increases the release of nutrients. Cytotoxicity tests further demonstrate the excellent biocompatibility of the GN-ALG-DN hydrogels. This study highlights the design of robust shaped and structured supramolecular hydrogels from natural herb small molecules, which can serve as solid, edible, and stimuli-responsive active cargo delivery platforms for food, biomedical, and sustainable applications.

Plasma-Enabled Graphene Quantum Dot Hydrogels as Smart Anticancer Drug Nanocarriers

One of the major challenges on the way to low-cost, simple, and effective cancer treatments is the lack of smart anticancer drug delivery materials with the requisite of site-specific and microenvironment-responsive properties. This work reports the development of plasma-engineered smart drug nanocarriers (SDNCs) containing chitosan and nitrogen-doped graphene quantum dots (NGQDs) for drug delivery in a pH-responsive manner. Through a customized microplasma processing, a highly cross-linked SDNC with only 4.5% of NGQD ratio can exhibit enhanced toughness up to threefold higher than the control chitosan group, avoiding the commonly used high temperatures and toxic chemical cross-linking agents. The SDNCs demonstrate improved loading capability for doxorubicin (DOX) via π-π interactions and stable solid-state photoluminescence to monitor the DOX loading and release through the Förster resonance energy transfer (FRET) mechanism. Moreover, the DOX loaded SDNC exhibits anticancer effects against cancer cells during cytotoxicity tests at minimum concentration. Cellular uptake studies confirm that the DOX loaded SDNC can be successfully internalized into the nucleus after 12 h incubation period. This work provides new insights into the development of smart, environmental-friendly, and biocompatible nanographene hydrogels for the next-generation biomedical applications.

Hydrogel-guided strategies to stimulate an effective immune response for vaccine-based cancer immunotherapy

Cancer vaccines have attracted widespread interest in tumor therapy because of the potential to induce an effective antitumor immune response. However, many challenges including weak immunogenicity, off-target effects, and immunosuppressive microenvironments have prevented their broad clinical translation. To overcome these difficulties, effective delivery systems have been designed for cancer vaccines. As carriers in cancer vaccine delivery systems, hydrogels have gained substantial attention because they can encapsulate a variety of antigens/immunomodulators and protect them from degradation. This enables hydrogels to simultaneously reverse immunosuppression and stimulate the immune response. Meanwhile, the controlled release properties of hydrogels allow for precise temporal and spatial release of loads in situ to further enhance the immune response of cancer vaccines. Therefore, this review summarizes the classification of cancer vaccines, highlights the strategies of hydrogel-based cancer vaccines, and provides some insights into the future development of hydrogel-based cancer vaccines.

Magnetic Nanoparticles: Current Advances in Nanomedicine, Drug Delivery and MRI

Magnetic nanoparticles (MNPs) have evolved tremendously during recent years, in part due to the rapid expansion of nanotechnology and to their active magnetic core with a high surface-to-volume ratio, while their surface functionalization opened the door to a plethora of drug, gene and bioactive molecule immobilization. Taming the high reactivity of the magnetic core was achieved by various functionalization techniques, producing MNPs tailored for the diagnosis and treatment of cardiovascular or neurological disease, tumors and cancer. Superparamagnetic iron oxide nanoparticles (SPIONs) are established at the core of drug-delivery systems and could act as efficient agents for MFH (magnetic fluid hyperthermia). Depending on the functionalization molecule and intrinsic morphological features, MNPs now cover a broad scope which the current review aims to overview. Considering the exponential expansion of the field, the current review will be limited to roughly the past three years.