One-step preparation of photoclick method for embolic microsphere synthesis and assessment for transcatheter arterial embolization

Immobilized Drugs on Dual-Mode Imaging Ag2S/BaSO4/PVA Embolic Microspheres for Precise Localization, Rapid Embolization, and Local Antitumor Therapy

Transcatheter arterial embolization (TAE) in interventional therapy and tumor embolism therapy plays a significant role. The choice of embolic materials that have good biocompatibility is an essential component of TAE. For this study, we produced a multifunctional PVA embolization material that can simultaneously encapsulate Ag2S quantum dots (Ag2S QDs) and BaSO4 nanoparticles (BaSO4 NPs), exhibiting excellent second near-infrared window (NIR-II) fluorescence imaging and X-ray imaging, breaking through the limitations of traditional embolic microsphere X-ray imaging. To improve the therapeutic effectiveness against tumors, we doped the doxorubicin (DOX) antitumor drug into microspheres and combined it with a clotting peptide (RADA16-I) on the surface of microspheres. Thus, it not only embolizes rapidly during hemostasis but also continues to release and accelerate tumor necrosis. In addition, Ag2S/BaSO4/PVA microspheres (Ag2S/BaSO4/PVA Ms) exhibited good blood compatibility and biocompatibility, and the results of embolization experiments on renal arteries in rabbits revealed good embolic effects and bimodal imaging stability. Therefore, they could serve as a promising medication delivery embolic system and an efficient biomaterial for arterial embolization. Our research work achieves the applicability of NIR-II and X-ray dual-mode images for clinical embolization in biomedical imaging.

Synthesis and characterization of 3-in-1 multifunctional lipiodol-doped Fe3O4@Poly (diallyl isophthalate) microspheres for arterial embolization, chemotherapy, and imaging

Transcatheter arterial embolization plays a pivotal role in treating various diseases. However, the efficacy of embolization therapy in cancer treatment can be limited by several factors, such as inevitable incomplete or non-target embolization, and the tumor recurrence and metastasis caused by the hypoxic microenvironment. Moreover, it is essential to explore simpler, more economical, and efficient methods for microsphere synthesis. Herein, we achieved one-step photocatalytic synthesis of lipiodol-doped Fe3O4@Poly (diallyliso-phthalate) multifunctional microspheres (IFeD MS) for arterial embolization, chemotherapy, and imaging. The prepared microspheres are in the shape of dried plums, with a particle size of 100-300 μm. Lipiodol demonstrates a certain degree of chemotherapeutic activity, and the incorporation of Fe3O4enables the microspheres to exhibit magnetothermal response and magnetic resonance imaging capabilities. Furthermore, the radiopaque characteristics of both agents provide the microspheres with promising potential for computed tomography and digital radiography imaging. The renal embolization experiment in rabbits demonstrated that IFeD MS achieved significant embolization and chemotherapeutic effects. Biocompatibility experiments revealed that this embolic agent did not induce tissue damage or inflammation beyond the treatment area. Additionally, IFeD MS exhibited promising imaging potential. The results of this study imply that the developed multifunctional embolic agent IFeD MS may have significant potential in transforming tumors previously only suitable for palliative cares into resectable radical treatments.

Preparation and application of hemostatic microspheres containing biological macromolecules and others

Bleeding from uncontrollable wounds can be fatal, and the body's clotting mechanisms are unable to control bleeding in a timely and effective manner in emergencies such as battlefields and traffic accidents. For irregular and inaccessible wounds, hemostatic materials are needed to intervene to stop bleeding. Hemostatic microspheres are promising for hemostasis, as their unique structural features can promote coagulation. There is a wide choice of materials for the preparation of microspheres, and the modification of natural macromolecular materials such as chitosan to enhance the hemostatic properties and make up for the deficiencies of synthetic macromolecular materials makes the hemostatic microspheres multifunctional and expands the application fields of hemostatic microspheres. Here, we focus on the hemostatic mechanism of different materials and the preparation methods of microspheres, and introduce the modification methods, related properties and applications (in cancer therapy) for the structural characteristics of hemostatic microspheres. Finally, we discuss the future trends of hemostatic microspheres and research opportunities for developing the next generation of hemostatic microsphere materials.

Design of an imaging magnetic microsphere based on photopolymerization for magnetic hyperthermia in tumor therapy

Magnetic hyperthermia therapy has been widely used in the nonsurgical treatment of patients with advanced stage cancers that cannot be treated by surgery. It is minimally invasive, precise, and highly efficient and has a good curative effect. In this paper, a magnetic microsphere with Fe3O4 was prepared for thermal therapy and imaging based on a photoinitiated suspension polymerization method from biallelic monomers. The preparation method clearly minimized the degradative chain transfer of allyl polymerization reactions. The microspheres were characterized by microscope observation, spectral analysis, thermal analysis, and magnetic testing. The magnetothermal effect was detected by an infrared thermal imager in vitro and in vivo under a high-frequency alternating magnetic field (AMF). The antitumor effect was verified by testing the viability of H22 cells and observing a tumor-bearing mouse model under high-frequency AMF. Biocompatibility was evaluated by cell viability assay, tissue section observation, and blood biochemical analysis. The imaging capacity was tested by X-ray, MRI, and CT imaging experiments. The results show that the product has good dispersibility, thermal stability, superparamagnetism, and biocompatibility. Under the action of an AMF, the magnetic hyperthermia effect in tumor-bearing mice was better, and an antitumor effect could be achieved.

DFT studies of solvent effect in hydrogen abstraction reactions from different allyl-type monomers with benzoyl radical

Inert allyl-type monomers have been widely documented due to reduce degradation chain transfer. Recently, we and others discovered that the [3 + 2] cyclization reaction process by a photo-driven radical reaction, which can accelerate the polymerization. It was discovered that allyl ether monomers had much higher reactivity than other allyl monomers in the suspension photopolymerization initiated by Type I photoinitiator. Since the hydrogen abstraction reaction (HAR) is the initial step of cyclization, and in order to clarify the influence of solvents effect, three allyl-type monomers were employed, containing "O", "N" and "S" atom as hydrogen donors. The benzoyl radical obtained from cleavage of photoinitiator was chosen as hydrogen acceptors. We explored the hydrogen abstraction reaction in different solvents (methanol, water and DMSO) by quantum chemistry for geometry and energy. An investigation was undertaken regarding the structural orbital by electrostatic potential (ESP) and topological analysis (ELF and LOL). The findings were also combined with the distortion model and transition state theory. We obtained the molecular interactions used independent gradient method in the Hirshfeld molecular density partition (IGMH). The Eckart's correction allowed to examine the driving factors of the hydrogen abstraction reaction tunnels and these reactions constant rates are determined in the range of 500-2500 K depending on the modified Arrhenius form in different solvents effect. Our results can provide an answer for the different reactivities.

One-step Photocatalytic Synthesis of Fe3O4@Polydiallyl Isophthalate Magnetic Microspheres for Magnetocaloric Tumor Ablation and Its Potential for Tracing on MRI and CT

Allyl monomers that were previously considered to be difficult to polymerize are applied, and Fe₃O₄@polydiallyl isophthalate (Fe₃O₄@PDAIP) magnetic were synthesized by one-step photopolymerization. The skeleton of the microspheres is made of diallyl isophthalate (DAIP). We obtained the microspheres using the photo-click technique in a soft template with Nano-Fe₃O₄ evenly disseminated in hydrophobic DAIP by cation-π and polar interaction. The obtained Fe₃O₄@PDAIP magnetic microspheres can achieve tumor cell necrosis temperatures (41-52 ℃) in an alternating magnetic field due to their inherent magnetic response. The results of in vitro CT and MR imaging indicate that the microspheres might be monitored accurately in vivo. Then the structural characteristics of the microspheres were confirmed by morphological analysis and physicochemical property analysis. Experiments in vitro and in vivo revealed that the microspheres had an anti-tumor effect and their biocompatibility satisfies the standards. The stability experiment proves that the microspheres have the potential for long-term effectiveness in vivo. It demonstrates the promise of Fe₃O₄@PDAIP magnetic microspheres in clinical applications.

A comparison of hydrogen abstraction reaction between allyl-type monomers with thioxanthone-based photoinitiators without amine synergists

The photodriven radical-mediated [3 + 2] cyclization reaction was found to yield polymers efficiently without being hindered by degradative chain transfer. The first reaction is a hydrogen abstraction process in which one hydrogen atom migrates from the α-methylene group of an allyl monomer to the triplet state (or fragments) of the photoinitiator, thus yielding primary allyl radicals as primary radicals and then begins chain propagation via a 3 + 2 cyclization reaction. Allyl ether monomers were found to be significantly higher than other allyl monomers even with the absence of amine-like synergists. In order to clarify the procedure of the hydrogen abstraction mechanism, we used four allyl-type monomers as hydrogen donors and three thioxanthone photoinitiators as hydrogen acceptors by the quantum chemistry method in terms of geometry and energy. The results were interpreted with transition-state theory and the interaction/deformation model. Then, the tunneling factors of hydrogen abstraction reactions were also investigated by Eckart’s correction. The results show allyl ether systems are more reactive than other allyl systems, and it would provide us with new insights into these hydrogen abstractions.