Biocompatibility and Effectiveness Evaluation of a New Hemostatic Embolization Agent: Thrombin Loaded Alginate Calcium Microsphere

Mechanical investigation of a Tandem embolization-visualization system for minimally invasive procedures

Transcatheter arterial embolization is a minimally invasive intervention process in which the blood supply to a tumor or an abnormal area of tissue is blocked. One of the most commonly used embolic agents in clinics is microsphere (MS). In order to understand the flow behavior of microspheres in arteries, it is essential to study their mechanical properties systematically. In this work, calcium-alginate MSs with varying calcium concentrations were synthesized using a coaxial airflow method. Indocyanine green (ICG) was added as a fluorescent dye. The effect of ICG concentration change on microspheres was investigated by studying morphology, imageability, rheology, and swelling behavior. Then the effect of calcium chloride concentration change on microspheres was studied by conducting rheological tests, atomic force microscopy tests, hemolysis assay, and thrombogenicity assay. Results showed that microspheres with higher ICG concentrations have longer lasting fluorescence and lower storage modulus (G'). Higher concentrations of calcium chloride led to higher G', while the local Young's modulus obtained by AFM test was not significantly affected. The MSs with and without ICG showed good hemocompatibility and thrombogenicity.

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.

A Novel Coacervate Embolic Agent for Tumor Chemoembolization

Transcatheter arterial chemoembolization (TACE) has proven effective in blocking tumor-supplied arteries and delivering localized chemotherapeutic treatment to combat tumors. However, traditional embolic TACE agents exhibit certain limitations, including insufficient chemotherapeutic drug-loading and sustained-release capabilities, non-biodegradability, susceptibility to aggregation, and unstable mechanical properties. This study introduces a novel approach to address these shortcomings by utilizing a complex coacervate as a liquid embolic agent for tumor chemoembolization. By mixing oppositely charged quaternized chitosan (QCS) and gum arabic (GA), a QCS/GA polymer complex coacervate with shear-thinning property is obtained. Furthermore, the incorporation of the contrast agent Iohexol (I) and the chemotherapeutic doxorubicin (DOX) into the coacervate leads to the development of an X-ray-opaque QCS/GA/I/DOX coacervate embolic agent capable of carrying drugs. This innovative formulation effectively embolizes the renal arteries without recanalization. More importantly, the QCS/GA/I/DOX coacervate can successfully embolize the supplying arteries of the VX2 tumors in rabbit ear and liver. Coacervates can locally release DOX to enhance its therapeutic effects, resulting in excellent antitumor efficacy. This coacervate embolic agent exhibits substantial potential for tumor chemoembolization due to its shear-thinning performance, excellent drug-loading and sustained-release capabilities, good biocompatibility, thrombogenicity, biodegradability, safe and effective embolic performance, and user-friendly application.

Chemical and physical modification of graphene oxide nano-sheets using casein, Zn-Al layered double hydroxide, alginate hydrogel, and magnetic nanoparticles for biomedical applications

In our study, we developed a novel nanobiocomposite using graphene oxide (GO), casein (Cas), ZnAl layered double hydroxide (LDH), sodium alginate (Alg), and Fe3O4 magnetic nanoparticles. To synthesize the GO, we used a modified Hummer's method and then covalently functionalized its surface with Cas protein. The functionalized GO was combined with as-synthesized ZnAl LDH, and the composite was conjugated with alginate hydrogel through the gelation process. Finally, we magnetized the nanobiocomposite using in-situ magnetization. The nanobiocomposite was comprehensively characterized using FT-IR, FE-SEM, EDX, and XRD. Its biological potential was assessed through cell viability, hemolysis, and anti-biofilm assays, as well as its application in hyperthermia. The MTT assay showed high cell viability percentages for Hu02 cells after 24, 48, and 72 h of incubation. The nanobiocomposite had a hemolytic effect lower than 3.84 %, and the measured bacterial growth inhibition percentages of E. coli and S. aureus bacteria in the presence of the nanobiocomposite were 52.18 % and 55.72 %, respectively. At a concentration of 1 mg.mL-1 and a frequency of 400 kHz, the nanocomposite exhibits a remarkable specific absorption rate (SAR) of 67.04 W.g-1, showcasing its promising prospects in hyperthermia applications.

Current research status and development prospects of embolic microspheres containing biological macromolecules and others

Transcatheter arterial embolization (TACE) has been used in the treatment of malignant tumors, sudden hemorrhage, uterine fibroids, and other diseases, and with advances in imaging techniques and devices, materials science, and drug release technology, more and more embolic agents that are drug-carrying, self-imaging, or have multiple functions are being developed. Microspheres provide safer and more effective therapeutic results as embolic agents, with their unique spherical appearance and good embolic properties. Embolic microspheres are the key to arterial embolization, blocking blood flow and nutrient supply to the tumor target. This review summarizes some of the currently published embolic microspheres, classifies embolic microspheres according to matrix, and summarizes the characteristics of the microsphere materials, the current status of research, directions, and the value of existing and potential applications. It provides a direction to promote the development of embolic microspheres towards multifunctionalization, and provides a reference to promote the research and application of embolic microspheres in the treatment of tumors.

Preparation, evaluation and application of MRI detectable sunitinib-loaded calcium alginate/poly(acrylic acid) hydrogel microspheres

Transcatheter arterial chemoembolization (TACE) is an effective method for the treatment of unresectable hepatocellular carcinoma. Although many embolic agents have been developed in TACE, there are few ideal embolic agents that combine drug loading, imaging properties and vessel embolization. Here, we developed novel magnetic embolic microspheres that could simultaneously load sunitinib malate (SU), be detected by magnetic resonance imaging (MRI) and block blood vessels. Calcium alginate/poly (acrylic acid) hydrogel microspheres (CA/PAA-MDMs) with superparamagnetic iron oxide nanoparticles (SPIONs) modified by citric acid were prepared by a drip and photopolymerization method. The embolization and imaging properties of CA/PAA-MDMs were evaluated through a series of experiments such as morphology, X-ray diffraction and X-ray photoelectron spectroscopy, magnetic responsiveness analysis, elasticity, cytotoxicity, hemolysis test, in vitro MRI evaluation, rabbit ear embolization and histopathology. In addition, the ability of drug loading and drug release of CA/PAA-MDMs were investigated by using sunitinib (SU) as the model drug. In conclusion, CA/PAA-MDMs showed outstanding drug loading capability, excellent imaging property and embolization effect, which would be expected to be used as a potential biodegradable embolic agent in the clinical interventional therapy.

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.

Preparation of thrombin-loaded calcium alginate microspheres with dual-mode imaging and study on their embolic properties in vivo

Transcatheter arterial embolization (TAE) has played a huge role in the interventional treatment of organ bleeding and accidental bleeding. Choosing bio-embolization materials with good biocompatibility is an important part of TAE. In this work, we prepared a calcium alginate embolic microsphere using high-voltage electrostatic droplet technology. The microsphere simultaneously encapsulated silver sulfide quantum dots (Ag2S QDs) and barium sulfate (BaSO4), and fixed thrombin on its surface. Thrombin can achieve an embolic effect while stopping bleeding. The embolic microsphere has good near-infrared two-zone (NIR-II) imaging and X-ray imaging effects, and the luminous effect of NIR-II is better than that of X-rays. This breaks the limitations of traditional embolic microspheres that only have X-ray imaging. And the microspheres have good biocompatibility and blood compatibility. Preliminary application results show that the microspheres can achieve a good embolization effect in the ear arteries of New Zealand white rabbits, and can be used as an effective material for arterial embolization and hemostasis. This work realizes the clinical embolization application of NIR-II combined with X-ray multimodal imaging technology in biomedical imaging, achieving complementary advantages and excellent results, more suitable for studying biological changes and clinical applications.

Emerging hemostatic materials for non-compressible hemorrhage control

Non-compressible hemorrhage control is a big challenge in both civilian life and the battlefield, causing a majority of deaths among all traumatic injury mortalities. Unexpected non-compressible bleeding not only happens in pre-hospital situations but also leads to a high risk of death during surgical processes throughout in-hospital treatment. Hemostatic materials for pre-hospital treatment or surgical procedures for non-compressible hemorrhage control have drawn more and more attention in recent years and several commercialized products have been developed. However, these products have all shown non-negligible limitations and researchers are focusing on developing more effective hemostatic materials for non-compressible hemorrhage control. Different hemostatic strategies (physical, chemical and biological) have been proposed and different forms (sponges/foams, sealants/adhesives, microparticles/powders and platelet mimics) of hemostatic materials have been developed based on these strategies. A summary of the requirements, state-of-the-art studies and commercial products of non-compressible hemorrhage-control materials is provided in this review with particular attention on the advantages and limitations of their emerging forms, to give a clear understanding of the progress that has been made in this area and the promising directions for future generations.

Recent advances and applications of microspheres and nanoparticles in transarterial chemoembolization for hepatocellular carcinoma

Transarterial chemoembolization (TACE) is a recommended treatment for patients suffering from intermediate and advanced hepatocellular carcinoma (HCC). As compared to the conventional TACE, drug-eluting bead TACE demonstrates several advantages in terms of survival, treatment response, and adverse effects. The selection of embolic agents is critical to the success of TACE. Many studies have been performed on the modification of the structure, size, homogeneity, biocompatibility, and biodegradability of embolic agents. Continuing efforts are focused on efficient loading of versatile chemotherapeutics, controlled sizes for sufficient occlusion, real-time detection intra- and post-procedure, and multimodality imaging-guided precise treatment. Here, we summarize recent advances and applications of microspheres and nanoparticles in TACE for HCC. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Silk Embolic Material for Catheter-Directed Endovascular Drug Delivery

Embolization is a catheter-based minimally invasive procedure that deliberately occludes diseased blood vessels for treatment purposes. A novel silk-based embolic material (SEM) that is developed and optimized to provide tandem integration of both embolization and the delivery of therapeutics is reported. Natural silk is processed into fibroin proteins of varying lengths and is combined with charged nanoclay particles to allow visibility and injectability using clinical catheters as small as 600 μm in diameter at lengths >100 cm. SEMs loaded with fluorochrome labeled bovine albumin and Nivolumab, which is among the most used immunotherapy drugs worldwide, demonstrate a sustained release profile in vitro over 28 days. In a porcine renal survival model, SEMs with labeled albumin and Nivolumab successfully embolize porcine arteries without recanalization and lead to the delivery of both albumin and Nivolumab into the interstitial space of the renal cortex. Mechanistically, it is shown that tissue delivery is most optimal when the internal elastic membrane of the embolized artery is disrupted. SEM is a potential next-generation multifunctional embolic agent that can achieve embolization and deliver a wide range of therapeutics to treat vascular diseases including tumors.

Theranostic nanobubbles towards smart nanomedicines

Targeted therapy and early accurate detection of malignant lesions are essential for the effectiveness of treatment and prognosis in cancer patients. The development of gaseous system as a versatile platform for the fabricated nanobubbles, has attracted much interest in improving the efficacy of ultrasound therapeutic, diagnostic, and theranostic platforms. Nano-sized bubble, as an ultrasound contrast agent, with spherical gas-filled structures exhibited contrast enhancement capability due to their inherent EPR effect. Additionally, nanobubbles exhibited good stability with extended retention time in the blood stream. The current review summarized various nanobubbles and discussed about the crucial parameters affecting the stability of ultrafine bubbles. Furthermore, therapeutic and theranostic gaseous systems for fighting against cancer were described.

Comparative evaluation of the effectiveness of a local hemostatic agent modified with a bio-organic composition

Constant attention to the study of the experience of using hemostatic products proposed for local bleeding arrest encourages new developments in this field. Modern hemostatics are porous multilayer systems with an inclusion of active coagulants. The results of the assessment of hemostatic activity obtained with the help of clinical and laboratory methods often do not lend themselves to cross-checking and statistical processing, and do not allow us to study objects with different physical and chemical properties. Methods of chemometrics, namely planimetry, allow you to visualize the parameters of sorption and hemocoagulation activity. A comparative planimetric study of commercial local hemostatic agents like Celox powder, sponges and napkins of various companies, zeolite powder, as well as new hemostatic compositions, which were given provisionally label A52 and A58, was carried out. It is shown that the hemostatic composition labeled as A52 leads to the activation of absorbent materials, the formation of a stable volumetric primary and secondary thrombus. A comparative evaluation of the effectiveness of a new hemostatic agent in an acute experiment shows a high expression of hemostasis (the time of primary hemostasis is 15-20 seconds) and no recurrence of bleeding for the studied samples compared to the reference.

Embolization of Vascular Malformations via In Situ Photocrosslinking of Mechanically Reinforced Alginate Microfibers using an Optical-Fiber-Integrated Microfluidic Device

Embolization, which is a minimally invasive endovascular treatment, is a safe and effective procedure for treating vascular malformations (e.g., aneurysms). Hydrogel microfibers obtained via spatiotemporally controllable in situ photocrosslinking exhibit great potential for embolizing aneurysms. However, this process is challenging because of the absence of biocompatible and morphologically stable hydrogels and the difficulty in continuously spinning the microfibers via in situ photocrosslinking in extreme endovascular environments such as those involving a tortuous geometry and high absorbance. A double-crosslinked alginate-based hydrogel with tantalum nanopowder (DAT) that exploits the synergistic effect of covalent crosslinking by visible-light irradiation and ionic crosslinking using Ca2+ , which is present in the blood, is developed in this study. Furthermore, an effective strategy to design and produce an optical-fiber-integrated microfluidic device (OFI-MD) that can continuously spin hydrogel microfibers via in situ photocrosslinking in extreme endovascular environments is proposed. As an embolic material, DAT exhibits promising characteristics such as radiopacity, nondissociation, nonswelling, and constant mechanical strength in blood, in addition to excellent cyto- and hemo-compatibilities. Using OFI-MD to spin DAT microfibers continuously can help fill aneurysms safely, uniformly, and completely within the endovascular simulator without generating microscopic fragments, which demonstrates its potential as an effective embolization strategy.

Immobilized thrombin on X-ray radiopaque polyvinyl alcohol/chitosan embolic microspheres for precise localization and topical blood coagulation

Trans-catheter arterial embolization (TAE) plays an important role in treating various diseases. The available embolic agents lack X-ray visibility and do not prevent the reflux phenomenon, thus hindering their application for TAE therapy. Herein, we aim to develop a multifunctional embolic agent that combines the X-ray radiopacity with local procoagulant activity. The barium sulfate nanoparticles (BaSO₄ NPs) were synthesized and loaded into the polyvinyl alcohol/chitosan (PVA/CS) to prepare the radiopaque BaSO₄/PVA/CS microspheres (MS). Thereafter, thrombin was immobilized onto the BaSO₄/PVA/CS MS to obtain the thrombin@BaSO₄/PVA/CS MS. The prepared BaSO₄/PVA/CS MS were highly spherical with diameters ranging from 100 to 300 μm. In vitro CT imaging showed increased X-ray visibility of BaSO₄/PVA/CS MS with the increased content of BaSO₄ NPs in the PVA/CS MS. The biocompatibility assessments demonstrated that the MS were non-cytotoxic and possessed permissible hemolysis rate. The biofunctionalized thrombin@BaSO₄/PVA/CS MS showed improved hemostatic capacity and facilitated hemostasis in vitro. Additionally, in vivo study performed on a rabbit ear embolization model confirmed the excellent X-ray radiopaque stability of the BaSO₄/PVA/CS MS. Moreover, both the BaSO₄/PVA/CS and thrombin@BaSO₄/PVA/CS MS achieved superior embolization effects with progressive ischemic necrosis on the ear tissue and induced prominent ultrastructural changes in the endothelial cells. The findings of this study suggest that the developed MS could act as a radiopaque and hemostatic embolic agent to improve the embolization efficiency.

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Excellent in vitro and in vivo visibility of BaSO₄/PVA/CS MS.

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Excellent cytocompatibility and hemocompatibility of BaSO₄/PVA/CS MS.

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Enhanced hemostatic capacity and hemostasis of thrombin@BaSO₄/PVA/CS MS.

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Potential application of thrombin@BaSO₄/PVA/CS MS for in vivo embolization.

Regulation of the Ocular Cell/Tissue Response by Implantable Biomaterials and Drug Delivery Systems

Therapeutic advancements in the treatment of various ocular diseases is often linked to the development of efficient drug delivery systems (DDSs), which would allow a sustained release while maintaining therapeutic drug levels in the target tissues. In this way, ocular tissue/cell response can be properly modulated and designed in order to produce a therapeutic effect. An ideal ocular DDS should encapsulate and release the appropriate drug concentration to the target tissue (therapeutic but non-toxic level) while preserving drug functionality. Furthermore, a constant release is usually preferred, keeping the initial burst to a minimum. Different materials are used, modified, and combined in order to achieve a sustained drug release in both the anterior and posterior segments of the eye. After giving a picture of the different strategies adopted for ocular drug release, this review article provides an overview of the biomaterials that are used as drug carriers in the eye, including micro- and nanospheres, liposomes, hydrogels, and multi-material implants; the advantages and limitations of these DDSs are discussed in reference to the major ocular applications.

Biocompatibility of a New Kind of Polyvinyl Alcohol Embolic Microspheres: In Vitro and In Vivo Evaluation

The aim of this study is to investigate the biocompatibility of polyvinyl alcohol (PVA) embolic microspheres by in vivo and in vitro evaluations. Two specifications of PVA microspheres including colorless microspheres (1 g microspheres with 7 mL 0.9% sodium chloride (SC) per vial, size: 500-700 µm) and blue microspheres (2 g microspheres with 7 mL 0.9% SC per vial, size: 500-700 µm) were assessed for biocompatibility. The vitro cytotoxicity was evaluated in L929 cells by MTT assay. Acute systemic toxicity and 28-repeat dose intravenous subchronic toxicity were assessed in 20 ICR mice and 40 SD rates, respectively. Skin sensitization was conducted in 30 adult albino guinea pigs by maximization test, in addition, intracutaneous reaction test was performed in New Zealand white rabbits. Hemolysis ratio of PVA microspheres was evaluated with rabbit blood. Moreover, test for genotoxicity was assessed by bacterial reverse mutation test and mouse lymphoma mutagenesis assay. No cytotoxicity, hemolysis, or acute toxicity of PVA microspheres was found, and slight fluctuations of biochemical indexes were observed in test of 28-day repeat dose intravenous subchronic toxicity, while these changes remained within our historical permitted range. Maximization test and intracutaneous reactivity test disclosed no irritation to skin or tissues. According to bacterial reverse mutation test and mouse lymphoma mutagenesis assay, no genotoxicity of PVA microspheres was observed. PVA microspheres showed excellent biocompatibility both in vivo and in vitro, and they were promising embolic materials for drug-eluting beads transarterial chemoembolization (DEB-TACE) therapy.

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Antitumor Effects of Ruyiping on Cell Growth and Metastasis in Breast Cancer

Background: Ruyiping is an effective traditional Chinese herbal medicine formula for preventing postoperative recurrence and metastasis of breast cancer. However, the exact function and underlying mechanism of Ruyiping in breast cancer remain unclear. Materials and Methods: After breast cancer cell lines MDA-MB-231 and MDA-MB-468 were treated with Ruyiping, the CCK8, colony formation, wound-healing, and transwell invasion assays were used to examine cell proliferation, migration, and invasion, respectively. Flow cytometry was performed to examine the effect of Ruyiping on cell cycle distribution. Western blot was performed to examine the expression of related proteins, and the activity of MMP9 was detected using Gelatin zymography assay. Results: Ruyiping treatment significantly inhibited cell proliferation and viability of MDA-MB-231 and MDA-MB-468 cells. Ruyiping was also revealed to trigger cell cycle arrest at the G2 phase in MDA-MB-231 and MDA-MB-468 cells. Moreover, Ruyiping suppressed the migration and invasion abilities of MDA-MB-231 and MDA-MB-468 cells in vitro. Furthermore, Ruyiping blocked the activity of MMP9 in MDA-MB-231 and MDA-MB-468 cells. Additionally, western blotting showed that Ruyiping attenuated epithelial-to-mesenchymal transition (EMT) of breast cancer through downregulation of N-cadherin, Vimentin, Snail1, and Snail2 and upregulation of E-cadherin. The authors observed that the components of Ruyiping Pseudobulbus Cremastra seu pleiones polysaccharide and curcumol showed significant suppression in the growth and invasion of breast cancer cell. Conclusions: The observations of this study suggest the antitumor properties of Ruyiping in cell growth and invasion of breast cancer, which are modulated by induction of cell cycle arrest and reduction of MMP9 and EMT.