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

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.

Dual-Network Hydrogel Loaded With ROS-activated Hydrogen Sulfide Donor to Accelerate Wound Healing and Inhibit Scar Production

The wound healing process consists of four continuous and overlapping stages-hemostasis, inflammation, proliferation, and remodeling-involving a variety of cells, growth factors, and the extracellular matrix. In recent years, growing evidence has shown that enhancing endogenous hydrogen sulfide (H2S) synthesis or providing exogenous H2S can promote angiogenesis, inhibit inflammation, reduce excessive oxidative stress, and support collagen deposition. However, the administration of exogenous H2S often presents challenges related to controlling its release duration and achieving targeted delivery. To achieve controlled and site-specific delivery of H2S to the wound area, a dual-network cross-linked injectable hydrogel formed by grafted ε-poly-L-lysine (designed as EG) and oxidized dextran (OD) (EGODF) loaded with a hydrogen sulfide donor (HSDF-NH2) to study its potential in wound healing is developed. The hydrogel exhibits excellent injectability, self-healing capability, and mechanical strength. Upon reactive oxygen species (ROS) stimulation, HSDF-NH2 releases both self-reporter fluorescence (HSDG-NH2) and H2S. Changes in the self-reporter fluorescence signal reflect H2S production and its entry into the body to exert therapeutic effects. Finally, using a wound model and a hypertrophic scar repair model, it is demonstrated that EGODF hydrogel is effective in promoting wound healing and inhibiting scar production.

Thrombin Immobilized Hemocompatible Radiopaque Polyurethane Microspheres for Topical Blood Coagulation

Over the past decade, there has been growing interest in developing microspheres for embolization procedures. However, the lack of noninvasive monitoring of the embolic agents and the occurrence of reflux phenomenon leading to unintentional occlusions has raised concerns regarding their compatibility/suitability for embolization therapy. Here we report the development of specialty microspheres having intrinsic radiopacity and surface functionality to tackle the existing complications that pave the way for more advanced solutions. To achieve the above goal, an iodinated monomer, termed "IBHV," capable of imparting radiopacity and functionality, was synthesized and used as a chain extender to make radiopaque polyurethane. Microspheres with a smooth surface and an average diameter of 474 ± 73 μm were fabricated from this polyurethane. The microspheres obtained were noncytotoxic, had a permissible hemolysis rate, and showed better traceability on x-ray imaging. Subsequent immobilization of thrombin onto microspheres improved their hemostatic effect. This study demonstrated that immobilization of thrombin would lead to microspheres with unique traits of radiopacity and hemostatic properties, which will undoubtedly enhance embolization efficiency.

Emulsion-Based Multi-Phase Integrated Microbeads with Inner Multi-Interface Structure Enable Dual-Modal Imaging for Precision Endovascular Embolization

Microsphere-based embolic agents have gained prominence in transarterial embolization (TAE) treatment, a critical minimally invasive therapy widely applied for a variety of diseases such as hypervascular tumors and acute bleeding. However, the development of microspheres with long-term, real-time, and repeated X-ray imaging as well as ultrasound imaging remains challenging. In this study, emulsion-based dual-modal imaging microbeads with a unique internal multi-interface structure is developed for TAE treatment. The embolic microbeads are fabricated from a solidified oil-in-water (O/W) emulsion composed of crosslinked CaAlg-based aqueous matrix and dispersed radiopaque iodinated oil (IO) droplets through a droplet-based microfluidic fabrication method. The CaAlg-IO microbeads exhibit superior X-ray imaging visibility due to the incorporation of exceptionally high iodine level up to 221 mgI mL-1, excellent ultrasound imaging capability attributed to the multi-interface structure of the O/W emulsion, great microcatheter deliverability thanks to their appropriate biomechanical properties and optimal microbead density, and extended drug release behavior owing to the biodegradation nature of the embolics. Such an embolic agent presents a promising emulsion-based platform to utilize multi-phased structures for improving endovascular embolization performance and assessment capabilities.

Fusible and Radiopaque Microspheres for Embolization

In this work, fusible microspheres loaded with radiopaque agents as an embolic agent for transcatheter arterial embolization (TAE) are developed. A poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) multi-block copolymer basing polyurethane (PCEU) is synthesized and fabricated into blank microspheres (BMs). The microspheres are elastic in compression test. A clinical contrast agent lipiodol is encapsulated in the microspheres to receive fusible radiopaque microspheres (FRMs). The sizes of FRMs are uniform and range from 142.2 to 343.1 µm. The encapsulated lipiodol acts as the plasticizer to reduce the melting temperature point (Tm) of PECU microspheres, thus, leading to the fusion of microspheres to exhibit efficient embolization in vivo. The performance of FRMs is carried out on a rabbit ear embolization model. Serious ischemic necrosis is observed and the radiopacity of FRMs sustains much longer time than that of commercial contrast agent Loversol in vivo. The fusible and radiopaque microsphere is promising to be developed as an exciting embolic agent.

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.

Shape Self-Adaptive Liquid Embolic Agent for Ultrafast and Durable Vascular Embolization

Minimally invasive embolization greatly decreases the mortality resulting from vascular injuries while still suffering from a high risk of recanalization and systematic thrombosis due to the intrinsic hydrophobicity and poor adhesion of the clinically used liquid embolic agent of Lipiodol. In this study, a shape self-adaptive liquid embolic agent was developed by mixing biocompatible poly(acrylic acid) (PAA), two-dimensional magnesium-aluminum layered double hydroxide (LDH), and poly(ethylene glycol)200 (PEG200). Upon contact with blood, the injectable PAA-LDH@PEG200 would quickly absorb water to form an adhesive and mechanically strong PAA-LDH thin hydrogel within 5 s, which could firmly adhere to the blood vessel wall for ultrafast and durable embolization. In addition, benefiting from the "positively charged nucleic center effect" of LDH nanosheets, the liquid PAA-LDH@PEG200 could avoid vascular distension by PAA overexpansion and possess high shock-resistant mechanical strength from the blood flow. Furthermore, both in vitro and in vivo embolization experiments demonstrated the complete embolic capacity of liquid PAA-LDH@PEG200 without the occurrence of recanalization for 28 days and also the great potential to act as a platform to couple with chemotherapeutic drugs for the minimized transcatheter arterial chemoembolization (TACE) treatment of VX2 tumors without recurrence for 18 days. Thus, liquid PAA-LDH@PEG200 developed here possesses great potential to act as a shape self-adaptive liquid embolic agent for ultrafast and durable vascular embolization.

Novel radiopaque ethanol injection: physicochemical properties, animal experiments, and clinical application in vascular malformations

BACKGROUND

Despite the efficacy of absolute ethanol (EtOH), its radiolucency introduces several risks in interventional therapy for treating vascular malformations. This study aims to develop a novel radiopaque ethanol injection (REI) to address this issue.

METHODS

Iopromide is mixed with ethanol to achieve radiopacity and improve the physicochemical properties of the solution. Overall, 82 male New Zealand white rabbits are selected for in vivo radiopacity testing, peripheral vein sclerosis [animals were divided into the following 5 groups (n = 6): negative control (NC, saline, 0.250 ml/kg), positive control (EtOH, 0.250 ml/kg), low-dose REI (L-D REI, 0.125 ml/kg), moderate-dose REI (M-D REI, 0.250 ml/kg), and high-dose REI (H-D REI 0.375 ml/kg)], pharmacokinetic analyses (the blood sample was harvested before injection, 5 min, 10 min, 20 min, 40 min, 1 h, 2 h, 4 h, and 8 h after injection in peripheral vein sclerosis experiment), peripheral artery embolization [animals were divided into the following 5 groups (n = 3): NC (saline, 0.250 ml/kg), positive control (EtOH, 0.250 ml/kg), L-D REI (0.125 ml/kg), M-D REI (0.250 ml/kg), and H-D REI (0.375 ml/kg)], kidney transcatheter arterial embolization [animals were divided into the following 4 groups (n = 3): positive control (EtOH, 0.250 ml/kg), L-D REI (0.125 ml/kg), M-D REI (0.250 ml/kg), and H-D REI (0.375 ml/kg); each healthy kidney was injected with saline as negative control], and biosafety evaluations [animals were divided into the following 5 groups (n = 3): NC (0.250 ml/kg), high-dose EtOH (0.375 ml/kg), L-D REI (0.125 ml/kg), M-D REI (0.250 ml/kg), and H-D REI (0.375 ml/kg)]. Then, a prospective cohort study involving 6 patients with peripheral venous malformations (VMs) is performed to explore the clinical safety and effectiveness of REI. From Jun 1, 2023 to August 31, 2023, 6 patients [age: (33.3 ± 17.2) years] with lingual VMs received sclerotherapy of REI and 2-month follow-up. Adverse events and serious adverse events were evaluated, whereas the efficacy of REI was determined by both the traceability of the REI under DSA throughout the entire injection and the therapeutic effect 2 months after a single injection.

RESULTS

The REI contains 81.4% ethanol (v/v) and 111.3 mg/ml iodine, which can be traced throughout the injection in the animals and patients. The REI also exerts a similar effect as EtOH on peripheral venous sclerosis, peripheral arterial embolization, and renal embolization. Furthermore, the REI can be metabolized at a similar rate compared to EtOH and Ultravist® and did not cause injury to the animals' heart, liver, spleen, lungs, kidneys and brain. No REI-related adverse effects have occurred during sclerotherapy of VMs, and 4/6 patients (66.7%) have achieved complete response at follow-up.

CONCLUSION

In conclusion, REI is safe, exerts therapeutic effects, and compensates for the radiolucency of EtOH in treating VMs.

TRIAL REGISTRATION

The clinical trial was registered as No. ChiCTR2300071751 on May 24 2023.

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.

Transcatheter arterial embolization with N-butyl cyanoacrylate for postoperative hemorrhage treatment following pancreatoduodenectomy

PURPOSE

Postoperative hemorrhage (PPH) is a severe complication of pancreatoduodenectomy (PD) with a mortality rate of 5-20.2% and mortality due to hemorrhage of 11-58%. Transcatheter arterial embolization (TAE) has been widely recommended for PPH, however, TAE with N-butyl cyanoacrylate (NBCA) for PPH treatment has been reported rarely. Therefore, this study aimed to evaluate the safety and efficacy of TAE with NBCA for PPH treatment following PD.

METHODS

This retrospective study included 14 male patients (mean age, 60.93 ± 10.97 years) with postoperative hemorrhage following PD treated with TAE using NBCA as the main embolic agent from October 2019 to February 2022. The clinical data, technical and success rate, and complications were analyzed.

RESULTS

Among the 14 patients who underwent TAE, the technical and clinical success rates were 100 and 85.71%, respectively. Angiography revealed contrast extravasation in 12 cases and a pseudoaneurysm in 3 cases. One patient developed a serious infection and died 2 days after the TAE.

CONCLUSION

TAE with NBCA for PPH treatment following PD, especially for massive hemorrhage caused by a pancreatic fistula, biliary fistula, or inflammatory corrosion, can result in rapid and effective hemostasis with high safety.

Antibacterial, antioxidant and fruit packaging ability of biochar-based silver nanoparticles-polyvinyl alcohol-chitosan composite film

Silver nanoparticles were prepared by loading Ag+ into biochar of waste barley distillers' grains shell by reduction with trisodium citrate, and this silver-loaded biochar was introduced into polyvinyl alcohol-chitosan. Various analysis with Fourier Transform Infrared spectroscopy, X-ray diffraction, Thermogravimetric analysis, and water contact angle revealed that biochar-based silver nanoparticle was incorporated into the polyvinyl alcohol-chitosan film, the biochar-based silver nanoparticles-polyvinyl alcohol-chitosan (C-Ag-loaded PVA/CS) composite film had good thermostability and hydrophobicity. Through the analysis via disk diffusion method, the composite containing 3 % of biochar-based silver nanoparticles-polyvinyl alcohol-chitosan had high antibacterial activity (inhibition zone: 18 mm against E. coli and 15 mm against S. aureus), and the bacterial membrane permeability was measured, indicating that C-Ag-loaded PVA/CS composite film could destroy the cell membrane, release intracellular substances, and have high antioxidant activity. During the storage, the weight loss rate of the biochar-based silver nanoparticles-polyvinyl alcohol-chitosan plastic wrap group was 0.14 %, and the titratable acid content only decreased by 0.061 %, which had a good effect on extending the shelf life of blueberries. The C-Ag-loaded PVA/CS composite film could also delay deterioration of blueberries and prolong storage time. Overall, this composite film had potential in food packaging and extending food shelf-life aspects.

Construction of Marigold-like Poly(vinyl alcohol) Microspheres for Catalytic Microreactors

It has long been pursued to develop polymer microspheres with various special morphologies and structures for better results in applications such as catalysis, drug delivery, and bioscaffolds. However, it remains a challenge to develop a facile method to produce poly(vinyl alcohol) (PVA) microspheres with special morphologies. Herein, a micron-sized marigold-like poly(vinyl alcohol) (CE-PVATPA) microsphere was engineered and fabricated by a feasible strategy, that is, emulsification-cross-linking, freeze-drying, and secondary acetal reaction steps. The morphological evolution of microspheres was systematically investigated under different conditions, and the procedure of constructing PVA microspheres with stabilizing marigold-like structures was proposed. More importantly, a specially structured PVA microsphere microreactor synergistically loading palladium metal nanoparticles (CE-PVATPA@Pd) for the heterogeneous catalyst 4-nitrophenol (4-NP) could be further demonstrated, which indicated high catalytic activity and excellent recyclability. The resultant stabilized fabricating method is promising to provide valuable guidance for the design and fabrication of a high-performance PVA microsphere microreactor.

Mitigation of Benzene-Induced Haematotoxicity in Sprague Dawley Rats through Plant-Extract-Loaded Silica Nanobeads

Benzene, a potent carcinogen, is known to cause acute myeloid leukaemia. While chemotherapy is commonly used for cancer treatment, its side effects have prompted scientists to explore natural products that can mitigate the haematotoxic effects induced by chemicals. One area of interest is nano-theragnostics, which aims to enhance the therapeutic potential of natural products. This study aimed to enhance the effects of methanolic extracts from Ocimum basilicum, Rosemarinus officinalis, and Thymus vulgaris by loading them onto silica nanobeads (SNBs) for targeted delivery to mitigate the benzene-induced haematotoxic effects. The SNBs, 48 nm in diameter, were prepared using a chemical method and were then loaded with the plant extracts. The plant-extract-loaded SNBs were then coated with carboxymethyl cellulose (CMC). The modified SNBs were characterized using various techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. The developed plant-extract-loaded and CMC-modified SNBs were administered intravenously to benzene-exposed rats, and haematological and histopathological profiling was conducted. Rats exposed to benzene showed increased liver and spleen weight, which was mitigated by the plant-extract-loaded SNBs. The differential white blood cell (WBC) count was higher in rats with benzene-induced haematotoxicity, but this count decreased significantly in rats treated with plant-extract-loaded SNBs. Additionally, blast cells observed in benzene-exposed rats were not found in rats treated with plant-extract-loaded SNBs. The SNBs facilitated targeted drug delivery of the three selected medicinal herbs at low doses. These results suggest that SNBs have promising potential as targeted drug delivery agents to mitigate haematotoxic effects induced by benzene in rats.

Supramolecular Responsive Chitosan Microcarriers for Cell Detachment Triggered by Adamantane

Supramolecular responsive microcarriers based on chitosan microspheres were prepared and applied for nonenzymatic cell detachment. Briefly, chitosan microspheres (CSMs) were first prepared by an emulsion crosslinking approach, the surface of which was then modified with β-cyclodextrin (β-CD) by chemical grafting. Subsequently, gelatin was attached onto the surface of the CSMs via the host-guest interaction between β-CD groups and aromatic residues in gelatin. The resultant microspheres were denoted CSM-g-CD-Gel. Due to their superior biocompatibility and gelatin niches, CSM-g-CD-Gel microspheres can be used as effective microcarriers for cell attachment and expansion. L-02, a human fetal hepatocyte line, was used to evaluate cell attachment and expansion with these microcarriers. After incubation for 48 h, the cells attached and expanded to cover the entire surface of microcarriers. Moreover, with the addition of adamantane (AD), cells can be detached from the microcarriers together with gelatin because of the competitive binding between β-CD and AD. Overall, these supramolecular responsive microcarriers could effectively support cell expansion and achieve nonenzymatic cell detachment and may be potentially reusable with a new cycle of gelatin attachment and detachment.

Radionuclide-Labeled Microspheres for Radio-Immunotherapy of Hepatocellular Carcinoma

Brachytherapy, including radioactive seed implantation (RSI) and transarterial radiation therapy embolization (TARE), is an important treatment modality for advanced hepatocellular carcinoma (HCC), but the inability of RSI and TARE to treat tumor metastasis and recurrence limits their benefits for patients in the clinic. Herein, indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors-loaded alginate microspheres (IMs) are developed as radionuclide carriers with immunomodulatory functions to achieve effective radio-immunotherapy. The size and swelling properties of IMs can be facilely tailored by adjusting the calcium source during emulsification. Small/large IMs(SIMs/LIMs) are biocompatible and available for RSI and TARE, respectively, after 177 Lu labeling. Among them, 177 Lu-SIMs completely eliminated subcutaneous HCC in mice after intratumoral RSI. Moreover, in combination with anti-PD-L1, 177 Lu-SIMs not only eradicate primary tumors by RSI but also effectively inhibit the growth of distant tumors, wherein the potent abscopal effect can be ascribed to the immune stimulation of RSI and the modulation of the tumor immune microenvironment (TIME) by IDO1 inhibitors. In parallel, LIMs demonstrate excellent embolization efficiency, resulting in visible necrotic lesions in the central auricular artery of rabbits, which are promising for TARE in future studies. Collectively, a versatile therapeutic agent is provided to synchronously modulate the TIME during brachytherapy for efficient radio-immunotherapy of advanced HCC.

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.

The inhibiting effect of alpha-based TARE on embolized vessels and neovascularization

Transarterial embolization (TAE) is a personalized technology that offers precise delivery of chemotherapeutic drugs or selective internal radiation therapy for hepatocellular carcinoma (HCC). Beta-emitting radionuclide embolisms for TAE (β-based TARE) are commonly used in the clinic via inducing biochemical lethality on tumor cells, while alpha-emitting radionuclides-based embolisms for TAE (α-based TARE) are still under study. The feeding artery plays a key role in tumor growth, metastasis, and recurrence. In this research, the auricular central arteries (ACAs) of rabbits were embolized with silk fibroin-based microspheres (SFMs) or SFMs integrated with α (Ra-223) or β (I-131) radionuclides to investigate the influence on vessels. TARE-induced tissue necrosis and the following neovascularization were measured by pathological analysis and 68Ga-DOTA-RGD PET/CT. The results showed that, compared to I-131, Ra-223 enhanced the growth inhibition of human hepatoma cells Huh-7 and induced more DNA double-strand breaks in vascular smooth muscle cells. Unlike β-based TARE, which mainly led to extensive necrosis of surrounding tissues, α-based TARE induced irreversible necrosis of a limited area adjacent to the embolized vessels. RGD PET revealed the inhibition on neovascularization in α-based TARE (SUVmax = 0.053 ± 0.004) when compared with normal group (SUVmax = 0.099 ± 0.036), the SFMs-lipiodol group (SUVmax = 0.240 ± 0.040), and β-based TARE (SUVmax = 0.141 ± 0.026), owing to the avoidance of the embolism-induced neovascularization. In conclusion, α-based TARE provided a promising strategy for HCC treatments via destroying the embolized vessels and inhibiting neovascularization.

Microencapsulation of Lacticaseibacillus rhamnosus GG for Oral Delivery of Bovine Lactoferrin: Study of Encapsulation Stability, Cell Viability, and Drug Release

Probiotics are delivered orally for treating gastrointestinal tract (GIT) infections; thus, they should be protected from the harsh environment of the GIT, such as through microencapsulation. Here, we microencapsulated cells of the probiotic Lacticaseibacillus rhamnosus GG via the liquid-droplet-forming method and evaluated them for oral delivery of bovine lactoferrin (bLf). Briefly, sodium alginate capsules (G-capsules) were first prepared, crosslinked with calcium chloride (C-capsules), and then modified with disodium hydrogen phosphate (M-capsules). All capsules showed good swelling behavior in the order of G-capsules > C-capsules > M-capsules in simulated gastric fluid (SGF, pH 2) and simulated intestinal fluid (SIF, pH 7.2). FE-SEM observations showed the formation of porous surfaces and successful microencapsulation of L. rhamnosus GG cells. The microencapsulated probiotics showed 85% and 77% viability in SGF and SIF, respectively, after 300 min. Compared to the 65% and 70% viability of gelation-encapsulated and crosslinking-encapsulated L. rhamnosus GG cells, respectively, the mineralization-encapsulated cells showed up to 85% viability after 300 min in SIF. The entrapment of bLf in the mineralization-encapsulated L. rhamnosus GG cells did not show any toxicity to the cells. FTIR spectroscopy confirmed the successful surface modification of L. rhamnosus GG cells via gelation, crosslinking, and mineralization, along with the entrapment of bLf on the surface of microencapsulated cells. The findings of these studies show that the microencapsulated L. rhamnosus GG cells with natural polyelectrolytes could be used as stable carriers for the oral and sustainable delivery of beneficial biotherapeutics without compromising their viability and the activity of probiotics.

CT/MR detectable magnetic microspheres for self-regulating temperature hyperthermia and transcatheter arterial chemoembolization

The embolic microspheres containing magnetic nanoparticles and anti-tumor drugs have been proposed for transcatheter arterial chemoembolization (TACE). However, this technique still suffers the poor control of hyperthermia temperature and drug release behavior. Herein, the magnetic microspheres based on low Curie temperature superparamagnetic iron oxide nanoparticles are developed by emulsification cross-linking of gelatin, genipin, and sodium alginate. The magnetic microspheres can self-regulate the hyperthermia temperature at around 50°C, un-necessitating any temperature control facilities. The magnetic microspheres can load doxorubicin hydrochloride and the loaded drug can be released in a controllable way by using an alternating magnetic field. Cytocompatibility and hemolysis evaluations confirm the non-cytotoxicity and negligible hemolysis of magnetic microspheres. The embolization model on rabbit auricular artery demonstrates that the magnetic microspheres can occlude the targeted blood vessel and are visualized under CT/MR imaging. All these findings suggest that the prepared magnetic microspheres could be used as the embolic agent in TACE. STATEMENT OF SIGNIFICANCE: The existing magnetic embolic microspheres suffer the poor control of hyperthermia temperature and drug release behavior in TACE. In this work, we developed the magnetic embolic microspheres based on superparamagnetic iron oxide nanoparticles with a low Curie temperature. Upon the application of alternating magnetic field, the embolic microspheres can self-regulate the hyperthermia temperature at around 50°C and the drug loaded in the microspheres can be released in a somewhat controllable manner. The embolic microspheres are also detectable to both CT and MR. These characteristics enable the developed microspheres to simultaneously realize self-regulating temperature hyperthermia, on-demand drug release, embolism, and CT/MR imaging.

Cellulose-Based Cryogel Microspheres with Nanoporous and Controllable Wrinkled Morphologies for Rapid Hemostasis

First-aid hemostatic agents for acute bleeding can save lives in emergency situations. However, rapid hemostasis remains challenging when uncontrolled hemorrhage occurs on lethal noncompressible and irregular wounds. Herein, cellulose-based cryogel microspheres with deliberately customized micromorphologies for ultrafast water transportation and diffusion, including the shark skin riblet-inspired wrinkled surface with low fluid drag and the hydrophilic nanoporous 3D networks, are developed to deal with the acute noncompressible bleeding within seconds. These cryogel microspheres can rapidly absorb a large amount of blood over 6 times their own weight in 10 s and form a robust barrier to seal a bleeding wound without applying pressure. Remarkably, massive bleeding from a cardiac penetrating hole is effectively stopped using the microspheres within 20 s and no blood leakage is observed after 30 min. Additionally, these microspheres could be readily removed without rebleeding and capillary thrombus, which is highly favorable to rapid hemostasis in emergency rescue.

The sodium hyaluronate microspheres fabricated by solution drying for transcatheter arterial embolization

Transcatheter arterial embolization (TAE) is an effective therapeutic method for several clinical ailments. Interminably, the polymer microsphere is reflected as one of the idyllic embolic materials due to the exceptional...

Rapid hemostasis and high bioactivity cerium-containing mesoporous bioglass for hemostatic materials

A two-step-acid-catalyzed-self-assembly method was used to prepare cerium-containing mesoporous bioactive glass with P123 as a template. The results showed that MBG without cerium and MBG with cerium slightly affected its surface area, and its water absorption rate was significantly higher. In vitro coagulation experiments showed that Ce-MBG significantly reduces prothrombin time (PT) and activated partial thromboplastin time (APTT), indicating that MBG containing Ce could promote coagulation and platelet adhesion compared with MBG. These suggested that Ce-MBG may be a good dressing with hemostatic properties, which could shorten the bleeding time of the wound and control the bleeding.

Injectable and thermosensitive hydrogels mediating a universal macromolecular contrast agent with radiopacity for noninvasive imaging of deep tissues

It is very challenging to visualize implantable medical devices made of biodegradable polymers in deep tissues. Herein, we designed a novel macromolecular contrast agent with ultrahigh radiopacity (iodinate content > 50%) via polymerizing an iodinated trimethylene carbonate monomer into the two ends of poly(ethylene glycol) (PEG). A set of thermosensitive and biodegradable polyester-PEG-polyester triblock copolymers with varied polyester compositions synthesized by us, which were soluble in water at room temperature and could spontaneously form hydrogels at body temperature, were selected as the demonstration materials. The addition of macromolecular contrast agent did not obviously compromise the injectability and thermogelation properties of polymeric hydrogels, but conferred them with excellent X-ray opacity, enabling visualization of the hydrogels at clinically relevant depths through X-ray fluoroscopy or Micro-CT. In a mouse model, the 3D morphology of the radiopaque hydrogels after injection into different target sites was visible using Micro-CT imaging, and their injection volume could be accurately obtained. Furthermore, the subcutaneous degradation process of a radiopaque hydrogel could be non-invasively monitored in a real-time and quantitative manner. In particular, the corrected degradation curve based on Micro-CT imaging well matched with the degradation profile of virgin polymer hydrogel determined by the gravimetric method. These findings indicate that the macromolecular contrast agent has good universality for the construction of various radiopaque polymer hydrogels, and can nondestructively trace and quantify their degradation in vivo. Meanwhile, the present methodology developed by us affords a platform technology for deep tissue imaging of polymeric materials.