Multifunctional Yolk-Shell Structured Magnetic Mesoporous Polydopamine/Carbon Microspheres for Photothermal Therapy and Heterogenous Catalysis

Smart Polymer Microspheres: Preparation, Microstructures, Stimuli-Responsive Properties, and Applications

Smart polymer microspheres (SPMs) are a class of stimulus-responsive materials that undergo physical, chemical, or property changes in response to external stimuli, such as temperature, pH, light, and magnetic fields. In recent years, their diverse responsiveness and tunable structures have enabled broad applications in biomedicine, environmental protection, information encryption, and other fields. This study provides a detailed review of recent preparation methods of SPMs, focusing on physical methods such as emulsification-solvent evaporation, microfluidics, and electrostatic spraying as well as chemical approaches such as emulsion and precipitation polymerization. Meanwhile, different types of stimulus-responsive behaviors, such as temperature-, pH-, light-, and magnetic-responsiveness, are thoroughly examined. This study also explores the applications of SPMs in drug delivery, tissue engineering, and environmental monitoring, while discussing future technological challenges and development directions in this field.

A multimodal defect-rich nanoreactor triggers sono-piezoelectric tandem catalysis and iron metabolism disruption for implant infections

Tracking and eradicating drug-resistant bacteria are critical for combating implant-associated infections, yet effective antibacterial therapies remain elusive. Herein, we propose an oxygen vacancy-rich (BiFe)0.9(BaTi)0.1O3-x nanoreactor as a piezoelectric sonosensitizer by spatiotemporal ultrasound-driven sono- and chemodynamic tandem catalysis to amplify antibacterial efficacy. The piezoelectric charge carriers under a built-in electric field synchronize the reaction of O2 and H2O, efficiently generating H2O2. The electron-rich oxygen vacancies modulate the local electronic structure of an Fe site. It facilitates reactive oxygen species generation by piezoelectric electrons and accelerates valence state cycles of Fe(III)/Fe(II) to achieve the sustained maintenance of hydroxyl radicals via H2O2/Fe(II)-catalyzed chemodynamic reactions, which lead to bacterial membrane damage. Transcriptomics analysis revealed that intracellular Fe overload induced by excessive Fe(II)-mediated dysregulation of the two-component system disrupts bacterial metabolism, triggering bacterial ferroptosis-like death. Thus, the porous titanium scaffold, engineered with a piezoelectric nanoreactor, demonstrates superior antibacterial efficacy under ultrasound and facilitates osteogenesis via piezoelectric immunomodulation-activated therapy.

A biomimetic dual-targeting nanomedicine for pancreatic cancer therapy

The physiological characteristics of pancreatic cancer (PC) involve the interplay between tumor cells, cancer-associated fibroblasts (CAF) and the extracellular matrix (ECM). This intricate microenvironment contributes to the cancer's resistance to conventional chemoradiotherapy and its poor prognosis. Carbon monoxide (CO), a promising molecule in gas therapy, can effectively penetrate solid tumors and induce tumor cell apoptosis at high concentrations. However, precise dosing control remains a significant challenge in the administration of exogenous CO, and its inherent toxicity at elevated concentrations presents substantial barriers to clinical translation. In this study, we developed a novel biomimetic nanomedical drug delivery system capable of simultaneously targeting CAF and PC tumor cells, degrading the ECM, and inhibiting tumor growth. The strategy integrates iron carbonyl (FeCO), an anti-cancer agent, and losartan (Lo), a drug that degrades tumor matrix, into a biodegradable nanomaterial-mesoporous polydopamine (MPDA). The resulting nanoparticles are then coated with CAF cell membranes (CAFM) and functionalized with plectin-1 targeted peptide (PTP), a molecule that targets PC cells, to construct the (Lo + FeCO)@MPDA@CAFM-PTP nanomedicine. This system utilizes the homologous adhesion properties of CAF membranes to target CAFs, delivering Lo to degrade the ECM. Following ECM degradation, the nanomedicine penetrates further to bind to PC tumor cells via PTP. Then anti-cancer drug FeCO is released to react with the excessive reactive oxygen species (ROS) in PC tumor cells to produce high concentrations of CO, effectively inducing tumor cell apoptosis. The (Lo + FeCO)@MPDA@CAFM-PTP nanomedicine demonstrated significant cytotoxicity against Panc-1 cells in vitro and effectively inhibited PC tumor growth in vivo. This innovative approach holds great promise for advancing pancreatic cancer treatment.

Polydopamine-functionalized capsules: From design to applications

In recent years, polydopamine (PDA)-functionalized capsules have garnered significant interest from researchers in the field of materials, owing to its remarkable properties of adhesion, biocompatibility, photothermal conversion capabilities, chemical reactivity, and so on. At present, numerous studies have reported various structures and morphologies of PDA-functionalized capsules fabricated via diverse strategies, that have found applications across a broad spectrum of disciplines. However, there are few comprehensive and systematic reviews focusing on various preparation strategies of PDA-functionalized capsules with various structures. This paper systematically reviewed the preparation strategies and related applications of PDA-functionalized capsules. These strategies of PDA-functionalized capsules were discussed in detail from four parts including PDA-functionalized capsules based on hollow PDA, mesoporous PDA (MPDA), directly encapsulating emulsion, and surface modification of capsules. Then the review outlined the applications of PDA-functionalized capsules in biomedicine, energy, textiles, and the environment. Furthermore, this review summarized the current research findings on PDA-functionalized capsules and outlines their future development directions. Overall, we aim for this review to inspire researchers and offer valuable guidance for the synthesis and application of advanced PDA-functionalized capsules.

Magnetic yolk-shell structured periodic mesoporous organosilica supported palladium as a powerful and highly recoverable nanocatalyst for the reduction of nitrobenzenes

A novel palladium-loaded yolk-shell structured nanomaterial with magnetite core and phenylene-based periodic mesoporous organosilica (PMO) shell (Fe3O4@YS-Ph-PMO/Pd) nanocatalyst was synthesized for the reduction of nitrobenzenes. The Fe3O4@YS-Ph-PMO/Pd was prepared through cetyltrimethylammonium bromide (CTAB) directed condensation of 1,4-bis(triethoxysilyl)benzene (BTEB) around Fe3O4@silica nanoparticles followed by treatment with palladium acetate. This nanocatalyst was characterized by using Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), low-angle and wide-angle powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) analyses. These analyses showed a magnetic nanomaterial with high chemical and thermal stability for the designed composite. The Fe3O4@YS-Ph-PMO/Pd nanocomposite was employed as a powerful and highly recoverable catalyst in the green reduction of nitroarenes in H2O at room temperature. A variety of nitroarene derivatives were applied as substrate in the presence of 0.9 mol% of Fe3O4@YS-Ph-PMO/Pd catalyst. All nitroarenes were selectively converted to their corresponding amines with high to excellent yields (92-96%) within short reaction times (10-18 min). This catalyst was recovered and reused at least 11 times without significant decrease in efficiency and stability.

Aspergillus oryzae β-D-galactosidase immobilization on glutaraldehyde pre-activated amino-functionalized magnetic mesoporous silica: Performance, characteristics, and application in the preparation of sesaminol

Aspergillus oryzae β-D-galactosidase (β-Gal) efficiently hydrolyzes sesaminol triglucoside into sesaminol, which has higher biological activity. However, β-Gal is difficult to be separate from the reaction mixture and limited by stability. To resolve these problems, β-Gal was immobilized on amino-functionalized magnetic nanoparticles mesoporous silica pre-activated with glutaraldehyde (Fe3O4@mSiO2-β-Gal), which was used for the first time to prepare sesaminol. Under the optimal conditions, the immobilization yield and recovered activity of β-Gal were 57.9 ± 0.3 % and 46.5 ± 0.9 %, and the enzymatic loading was 843 ± 21 Uenzyme/gsupport. The construction of Fe3O4@mSiO2-β-Gal was confirmed by various characterization methods, and the results indicated it was suitable for heterogeneous enzyme-catalyzed reactions. Fe3O4@mSiO2-β-Gal was readily separable under magnetic action and displayed improved activity in extreme pH and temperature conditions. After 45 days of storage at 4 °C, the activity of Fe3O4@mSiO2-β-Gal remained at 92.3 ± 2.8 %, which was 1.29 times than that of free enzyme, and its activity remained above 85 % after 10 cycles. Fe3O4@mSiO2-β-Gal displayed higher affinity and catalytic efficiency. The half-life was 1.41 longer than free enzymes at 55.0 °C. Fe3O4@mSiO2-β-Gal was employed as a catalyst to prepare sesaminol, achieving a 96.7 % conversion yield of sesaminol. The excellent stability and catalytic efficiency provide broad benefits and potential for biocatalytic industry applications.

In Vitro Synergistic Photodynamic, Photothermal, Chemodynamic, and Starvation Therapy Performance of Chlorin e6 Immobilized, Polydopamine-Coated Hollow, Porous Ceria-Based, Hypoxia-Tolerant Nanozymes Carrying a Cascade System

A synergistic therapy agent (STA) with photothermal, photodynamic, chemodynamic, and starvation therapy (PTT, PDT, CDT, and ST) functions was developed. Hollow, mesoporous, and nearly uniform CeO2 nanoparticles (H-CeO2 NPs) were synthesized using a staged shape templating sol-gel protocol. Chlorin e6 (Ce6) was adsorbed onto H-CeO2 NPs, and a thin polydopamine (PDA) layer was formed on Ce6-adsorbed H-CeO2 NPs. Glucose oxidase (GOx) was bound onto PDA-coated Ce6-adsorbed H-CeO2 NPs to obtain the targeted STA (H-CeO2@Ce6@PDA@GOx NPs). A reversible photothermal conversion behavior with the temperature elevations up to 34 °C was observed by NIR laser irradiation at 808 nm. A cascade enzyme system based on immobilized GOx and intrinsic catalase-like activity of H-CeO2 NPs was rendered on STA for enhancing the effectiveness of PDT by elevation of ROS generation and alleviation of hypoxia in a tumor microenvironment. Glucose-mediated generation of highly toxic hydroxyl radicals (·OH) was evaluated for CDT. The effectiveness of PDT on glioblastoma T98G cells was markedly enhanced by O2 generation started by the decomposition of glucose. A similar increase in cell death was also observed when ST and CDT functions were enhanced by photothermal action. The viability of T98G cells decreased to 10.6% by in vitro synergistic action including ST, CDT, PDT, and PTT without using any antitumor agent.

Nitrogen-oxygen co-doped carbon@silica hollow spheres as encapsulated Pd nanoreactors for acetylene dialkoxycarbonylation

The introduction of heteroatoms into hollow carbon spheres is imperative for enhancing catalytic activity. Consequently, we investigated the utilization of nitrogen-oxygen(N/O) co-doped hollow carbon (C)/silica (SiO2) nanospheres (NxC@mSiO2), which have a large internal volume and a nano-constrained environment that limits metal aggregation and loss, making them a potential candidate. In this study, we demonstrate the synthesis of nitrogen-oxygen (N/O) co-doped hollow carbon spheres using resorcinol and formaldehyde as carbon precursors, covered with silica, and encapsulated with palladium nanoparticles (NPs) in situ. The N/O co-doping process introduced defects on the surface of the internal C structure, which acted as active sites and facilitated substrate adsorption. Subsequent treatment with hydrogen peroxide (H2O2) introduced numerous carboxyl groups onto the C structure, increasing the catalytic environment as acid auxiliaries. The carboxyl group is present in the carbon structure, as determined calculations based on by density functional theory, reduces the adsorption energy of acetylene, thereby promoting its adsorption and enrichment. Furthermore, H2O2-treatment enhanced the oxygen defects in the carbon structure, improving the dispersion of Pd NPs and defect structure. The Pd/NxC@mSiO2-H2O2 catalysts demonstrated outstanding performance in the acetylene dialkoxycarbonylation reaction, showcasing high selectivity towards 1,4-dicarboxylate (>93 %) and remarkable acetylene conversion (>92 %). Notably, the catalyst exhibited exceptional selectivity and durability throughout the reaction.

Novel hierarchical carbon microspheres@layered double hydroxides@copper lignosulfonate architecture for polypropylene with enhanced flame retardant and mechanical performances

Due to the inherent defect of flammability of polypropylene (PP), a novel and highly efficient carbon microspheres@layered double hydroxides@copper lignosulfonate (CMSs@LDHs@CLS) flame retardant was designed and prepared, which was attributed to the strong electrostatic interaction between carbon microspheres (CMSs), layered double hydroxides (LDHs) and lignosulfonate as well as the chelation effect of lignosulfonate on copper ions, and then it was incorporated into the PP matrix. Significantly, CMSs@LDHs@CLS not only observably improved its dispersibility in PP matrix, but also simultaneously achieved excellent flame retardant properties for composites. With the addition of 20.0 % CMSs@LDHs@CLS, the limit oxygen index of CMSs@LDHs@CLS and PP composites (PP/CMSs@LDHs@CLS) reached 29.3 % and achieved the UL-94 V-0 rating. Cone calorimeter tests indicated that the peak heat release rate, total heat release and total smoke production of PP/CMSs@LDHs@CLS composites exhibited declines of 28.8 %, 29.2 % and 11.5 %, respectively, compared with those of PP/CMSs@LDHs composites. These advancements were attributed to the better dispersibility of CMSs@LDHs@CLS in PP matrix and illustrated that CMSs@LDHs@CLS observably reduced fire hazards of PP. The flame retardant property of CMSs@LDHs@CLS might relate to condensed phase flame retardant effect of char layer and catalytic charring of copper oxides.

Frontiers in Preparations and Promising Applications of Mesoporous Polydopamine for Cancer Diagnosis and Treatment

Polydopamine (PDA) is a natural melanin derived from marine mussels that has good biocompatibility, biodegradability, and photothermal conversion ability. As a new coating material, it offers a novel way to modify the surface of various substances. The drug loading capacity and encapsulation efficiency of PDA are greatly improved via the use of mesoporous materials. The abundant pore canals on mesoporous polydopamine (MPDA) exhibit a uniquely large surface area, which provides a structural basis for drug delivery. In this review, we systematically summarized the characteristics and manufacturing process of MPDA, introduced its application in the diagnosis and treatment of cancer, and discussed the existing problems in its development and clinical application. This comprehensive review will facilitate further research on MPDA in the fields of medicine including cancer therapy, materials science, and biology.

Mesoporous Nanoparticles for Diagnosis and Treatment of Liver Cancer in the Era of Precise Medicine

Primary liver cancer is the seventh-most-common cancer worldwide and the fourth-leading cause of cancer mortality. In the current era of precision medicine, the diagnosis and management of liver cancer are full of challenges and prospects. Mesoporous nanoparticles are often designed as specific carriers of drugs and imaging agents because of their special morphology and physical and chemical properties. In recent years, the design of the elemental composition and morphology of mesoporous nanoparticles have greatly improved their drug-loading efficiency, biocompatibility and biodegradability. Especially in the field of primary liver cancer, mesoporous nanoparticles have been modified as highly tumor-specific imaging contrast agents and targeting therapeutic medicine. Various generations of complexes and structures have been determined for the complicated clinical management requirements. In this review, we summarize these advanced mesoporous designs in the different diagnostic and therapeutic fields of liver cancer and discuss the relevant advantages and disadvantages of transforming applications. By comparing the material properties, drug-delivery characteristics and application methods of different kinds of mesoporous materials in liver cancer, we try to help determine the most suitable drug carriers and information media for future clinical trials. We hope to improve the fabrication of biomedical mesoporous nanoparticles and provide direct evidence for specific cancer management.