Facile Synthesis of a Multifunctional Porous Organic Polymer Nanosonosensitizer (mHM@HMME) for Enhanced Cancer Sonodynamic Therapy

Sonodynamic therapy (SDT), which involves the activation of sonosensitizers to generate cytotoxic reactive oxygen species under ultrasound irradiation, is a promising noninvasive modality for cancer treatment. However, the clinical translational application of SDT is impeded by the lack of efficient sonosensitizers, the inefficient accumulation of sonosensitizers at tumor sites, and the complicated immunosuppressive tumor microenvironment. Herein, we developed a facilely synthesized multifunctional porous organic polymer nanosonosensitizer (mHM@HMME) for enhanced SDT. Specifically, mHM@HMME nanosonosensitizers were prepared by incorporating chemotherapeutic mitoxantrone into the one-step synthesis process of disulfide bond containing porous organic polymers, followed by loading with organic sonosensitizer (HMME) and camouflaging with a cancer cell membrane. Due to the cancer cell membrane camouflage, this multifunctional mHM@HMME nanosonosensitizer showed prolonged blood circulation and tumor targeting aggregation. Under ultrasound irradiation, the mHM@HMME nanosonosensitizer exhibited a satisfactory SDT performance both in vitro and in vivo. Moreover, the potent SDT combined with glutathione-responsive drug release in tumor cells induced robust immunogenic cell death to enhance the antitumor effect of SDT in turn. Overall, this facilely synthesized multifunctional mHM@HMME nanosonosensitizer shows great potential application in enhanced SDT.

Highly Elastic and Anisotropic Wood-Derived Composite Scaffold with Antibacterial and Angiogenic Activities for Bone Repair

Scaffold-based tissue engineering is a promising strategy to address the rapidly growing demand for bone implants, but developing scaffolds with bone extracellular matrix-like structures, suitable mechanical properties, and multiple biological activities remains a huge challenge. Here, it is aimed to develop a wood-derived composite scaffold with an anisotropic porous structure, high elasticity, and good antibacterial, osteogenic, and angiogenic activities. First, natural wood is treated with an alkaline solution to obtain a wood-derived scaffold with an oriented cellulose skeleton and high elasticity, which can not only simulate collagen fiber skeleton in bone tissue but also greatly improve the convenience of clinical implantation. Subsequently, chitosan quaternary ammonium salt (CQS) and dimethyloxalylglycine (DMOG) are further modified on the wood-derived elastic scaffold through a polydopamine layer. Among them, CQS endows the scaffold with good antibacterial activity, while DMOG significantly improves the scaffold's osteogenic and angiogenic activities. Interestingly, the mechanical characteristics of the scaffolds and the modified DMOG can synergistically enhance the expression of yes-associated protein/transcriptional co-activator with PDZ binding motif signaling pathway, thereby effectively promoting osteogenic differentiation. Therefore, this wood-derived composite scaffold is expected to have potential application in the treatment of bone defects.

Green synthesis of glyco-CuInS2 QDs with visible/NIR dual emission for 3D multicellular tumor spheroid and in vivo imaging

Glyco-quantum dots (glyco-QDs) have attracted significant interest in bioimaging applications, notably in cancer imaging, because they effectively combine the glycocluster effect with the exceptional optical properties of QDs. The key challenge now lies in how to eliminate the high heavy metal toxicity originating from traditional toxic Cd-based QDs for in vivo bioimaging. Herein, we report an eco-friendly pathway to prepare nontoxic Cd-free glyco-QDs in water by the "direct" reaction of thiol-ending monosaccharides with metal salts precursors. The formation of glyco-CuInS₂ QDs could be explained by a nucleation-growth mechanism following the LaMer model. As-prepared four glyco-CuInS₂ QDs were water-soluble, monodispersed, spherical in shape and exhibited size range of 3.0-4.0 nm. They exhibited well-separated dual emission in the visible region (500-590 nm) and near-infrared range (~ 827 nm), which may be attributable to visible excitonic emission and near-infrared surface defect emission. Meanwhile, the cell imaging displayed the reversibly distinct dual-color (green and red) fluorescence in tumor cells (HeLa, A549, MKN-45) and excellent membrane-targeting properties of glyco-CuInS₂ QDs based on their good biorecognition ability. Importantly, these QDs succeed in penetrating uniformly into the interior (the necrotic zone) of 3D multicellular tumor spheroids (MCTS) due to their high negative charge (zeta potential values ranging from - 23.9 to - 30.1 mV), which overcame the problem of poor penetration depth of existing QDs in in vitro spheroid models. So, confocal analysis confirmed their excellent ability to penetrate and label tumors. Thus, the successful application in in vivo bioimaging of these glyco-QDs verified that this design strategy is an effective, low cost and simple procedure for developing green nanoparticles as cheap and promising fluorescent bioprobes.

Effect of Ionization Degree of Poly(amidoamine) Dendrimer and 5-Fluorouracil on the Efficiency of Complex Formation-A Theoretical and Experimental Approach

Due to their unique structure, poly(amidoamine) (PAMAM) dendrimers can bind active ingredients in two ways: inside the structure or on their surface. The location of drug molecules significantly impacts the kinetics of active substance release and the mechanism of internalization into the cell. This study focuses on the effect of the protonation degree of the G4PAMAM dendrimer and the anticancer drug 5-fluorouracil (5FU) on the efficiency of complex formation. The most favorable conditions for constructing the G4PAMAM-5FU complex are a low degree of protonation of the dendrimer molecule with the drug simultaneously present in a deprotonated form. The fluorine components in the XPS spectra confirm the formation of the stable complex. Through SAXS and DLS methods, a decrease in the dendrimer's molecular size resulting from protonation changes at alkaline conditions was demonstrated. The gradual closure of the dendrimer structure observed at high pH values makes it difficult for the 5FU molecules to migrate to the interior of the support structure, thereby promoting drug immobilization on the surface. The ¹H NMR and DOSY spectra indicate that electrostatic interactions determine the complex formation process. Through MD simulations, the localization profile and the number of 5FU molecules forming the complex were visualized on an atomic scale.

Synthesis of mesoporous-structured MIL-68(Al)/MCM-41-NH2 for methyl orange adsorption: Optimization and Selectivity

Here, we report a novel amino-modified mesoporous-structured aluminum-based metal-organic framework adsorbent, MIL-68(Al)/MCM-41-NH₂, for dye sewage treatment. The introduction of molecular sieves overcomes the inherent defects of microporous MOFs in contaminant transfer and provides more active sites to enhance adsorption efficiency. Compared with using organic amino ligands directly, this strategy is ten times cheaper. The composite was well characterized and analyzed in terms of morphology, structure and chemical composition. Batch experiments were carried out to study the influences of essential factors on the process, such as pH and temperature. In addition, their interactions and the optimum conditions were examined using response surface methodology (RSM). The adsorption kinetics, isotherms and thermodynamics were systematically elucidated. In detail, the adsorption process conforms to pseudo-second-order kinetics and follows the Sips and Freundlich isothermal models. Moreover, the maximum adsorption capacity Q_s of methyl orange (MO) was 477 mg g^-1. It could be concluded that the process was spontaneous, exothermic, and entropy-reducing. Several binary dye systems have been designed for selective adsorption research. Our material has an affinity for anionic pigments. The adsorption mechanisms were discussed in depth. The electrostatic interaction might be the dominant effect. Meanwhile, hydrogen bonding, π-π stacking, and pore filling might be important driving forces. The excellent thermal stability and recyclability of the adsorbent are readily noticed. After five reuse cycles, the composite still possesses a removal efficiency of 90% for MO. Overall, the efficient and low-cost composite can be regarded as a promising adsorbent for the selective adsorption of anionic dyes from wastewater.

Degradable Multifunctional Porphyrin-Based Porous Organic Polymer Nanosonosensitizer for Tumor-Specific Sonodynamic, Chemo- and Immunotherapy

Sonodynamic therapy (SDT) benefiting from its intrinsic merits, such as noninvasiveness and deep tissue penetrability, is receiving increasing considerable attention in reactive oxygen species (ROS)-based tumor treatment. However, current sonosensitizers usually suffer from low tumor lesion accumulation, insufficient ROS generation efficiency under ultrasound, and non-biodegradability, which seriously impede the therapeutic outcomes. Additionally, it is difficult that SDT alone can completely eradicate tumors because of the complex and immunosuppressive tumor microenvironment (TME). Herein, we simultaneously employ sonosensitive porphyrin building blocks and glutathione (GSH)-responsive disulfide bonds to construct a novel degradable multifunctional porphyrin-based hollow porous organic polymer (POP) nanosonosensitizer (H-Pys-HA@M/R), which combine SDT, "on-demand" chemotherapy, and immunotherapy. Taking the unique advantages of POPs with designable structures and high specific surface area, this H-Pys-HA@M/R nanosonosensitizer can achieve tumor target accumulation, GSH-triggered drug release, and low-frequency ultrasound-activating ROS generation with encouraging results. Furthermore, this multifunctional nanosonosensitizer can effectively evoke immunogenic cell death (ICD) response through the combination of SDT and chemotherapy for both primary and distal tumor growth suppression. Meanwhile, H-Pys-HA@M/R exhibits favorable biodegradation and biosafety. Therefore, this study provides a new strategy for reasonably designing and constructing POP-related sonosensitizers combining SDT/chemotherapy/immunotherapy triple treatment modalities to eradicate malignant tumors.