Development of PVA-based microsphere as a potential embolization agent

Fabrication of polymeric microspheres for biomedical applications

Polymeric microspheres (PMs) have attracted great attention in the field of biomedicine in the last several decades due to their small particle size, special functionalities shown on the surface and high surface-to-volume ratio. However, how to fabricate PMs which can meet the clinical needs and transform laboratory achievements to industrial scale-up still remains a challenge. Therefore, advanced fabrication technologies are pursued. In this review, we summarize the technologies used to fabricate PMs, including emulsion-based methods, microfluidics, spray drying, coacervation, supercritical fluid and superhydrophobic surface-mediated method and their advantages and disadvantages. We also review the different structures, properties and functions of the PMs and their applications in the fields of drug delivery, cell encapsulation and expansion, scaffolds in tissue engineering, transcatheter arterial embolization and artificial cells. Moreover, we discuss existing challenges and future perspectives for advancing fabrication technologies and biomedical applications of PMs.

Lithium and cobalt co-doped mesoporous bioactive glass nanoparticles promote osteogenesis and angiogenesis in bone regeneration

Healing of severe fractures and bone defects involves many complex biological processes, including angiogenesis and osteogenesis, presenting significant clinical challenges. Biomaterials used for bone tissue engineering often possess multiple functions to meet these challenges, including proangiogenic, proosteogenic, and antibacterial properties. We fabricated lithium and cobalt co-doped mesoporous bioactive glass nanoparticles (Li-Co-MBGNs) using a modified sol-gel method. Physicochemical analysis revealed that the nanoparticles had high specific surface areas (>600 m2/g) and a mesoporous structure suitable for hydroxyapatite (HA) formation and sustained release of therapeutic ions. In vitro experiments with Li-Co-MBGNs showed that these promoted angiogenic properties in HUVECs and pro-osteogenesis abilities in BMSCs by releasing Co2+ and Li+ ions. We observed their antibacterial activity against Staphylococcus aureus and Escherichia coli, indicating their potential applications in bone tissue engineering. Overall, our findings indicate the feasibility of its application in bone tissue engineering.

Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer: A review

The complication of diabetes, which is known as diabetic foot ulcer (DFU), is a significant concern due to its association with high rates of disability and mortality. It not only severely affects patients’ quality of life, but also imposes a substantial burden on the healthcare system. In spite of efforts made in clinical practice, treating DFU remains a challenging task. While mesenchymal stem cell (MSC) therapy has been extensively studied in treating DFU, the current efficacy of DFU healing using this method is still inadequate. However, in recent years, several MSCs-based drug delivery systems have emerged, which have shown to increase the efficacy of MSC therapy, especially in treating DFU. This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

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.

Robust Osteoconductive β-Tricalcium Phosphate/L-poly(lactic acid) Membrane via Orientation-Strengthening Technology

L-poly(lactic acid) (PLLA) is a biodegradable material with multiple biomedical application potentials, especially as a membrane for guided bone regeneration. In terms of its low strength and poor osteogenic activity, improving these two properties is the key to resolve the limitations of PLLA for bone-associated applications. Herein, an orientation-strengthening technology (OST) was developed to reinforce PLLA's mechanical strength by introducing biocompatible β-tricalcium phosphate (β-TCP) to improve the crystallinity of PLLA, allowing for the formation of a highly oriented architecture to acquire an advanced membrane with high mechanical property. Furthermore, the addition of β-TCP nanoparticles significantly promotes the osteogenic activity of the composites. The tensile strength of the membrane containing 5 wt % β-TCP was 220 MPa, which was 4-folds that of the native polylactic acid fabricated via the conventional method. The oriented microstructure enhanced both the mechanical strength and the osteogenic activity of the material. The parallel grooves on the material surface are similar to the mineralized collagen fibers on the bone surface, which promoted the growth and differentiation of osteoblasts, with β-TCP further contributing to the osteoconductive effect. The combination of β-TCP and orientation-strengthening effect endows the material with higher mechanical properties and bioactivities, which provides an advanced manufacturing strategy for the preparation of PLLA-based materials for bone repair.

Biomimetic nanovesicle co-delivery system impairs energy metabolism for cancer treatment

Metabolic reprogramming in cancer cells plays a crucial role in cancer development, metastasis and invasion. Cancer cells have a unique metabolism profile that could switch between glycolysis and oxidative phosphorylation (OXPHOS) in order to satisfy a higher proliferative rate and enable survival in tumor microenvironment. Although dietary-based cancer starvation therapy has shown some positive outcomes for cancer treatment, it is difficult for patients to persist for a long time due to the adverse effects. Here in this study, we developed a specific M1 macrophage-derived membrane-based drug delivery system for breast cancer treatment. Both metformin and 3-Bromopyruvate were loaded into the engineered cell membrane-based biomimetic carriers (Met-3BP-Lip@M1) for the shutdown of energy metabolism in cancer cells via simultaneous inhibition of both glycolysis and oxygen consumption. The in vitro studies showed that Met-3BP-Lip@M1 had excellent cancer cell uptake and enhanced cancer cell apoptosis via cell cycle arrest. Our results also demonstrated that this novel biomimetic nanomedicine-based cancer starvation therapy synergistically improved the therapeutic efficiency against breast cancer cells by blocking energy metabolic pathways, which resulted in a significant reduction of cancer cell proliferation, 3D tumor spheroid growth as well as in vivo tumor growth.

Nickel sulfide and dysprosium-doped nickel sulfide nanoparticles: Dysprosium-induced variation in properties, in vitro chemo-photothermal behavior, and antibacterial activity

Newer materials for utilization in multi-directional therapeutic actions are investigated, considering delicate design principles involving size and shape control, surface modification, and controllable drug loading and release. Multi-faceted properties are imparted to the engineered nanoparticles, like magnetism, near-infrared absorption, photothermal efficiency, and suitable size and shape. This report presents nickel sulfide and dysprosium-doped nickel sulfide nanoparticles with poly-β-cyclodextrin polymer coating. The nanoparticles belong to the orthorhombic crystal systems, as indicated by X-ray diffraction studies. The size and shape of the nanoparticles are investigated using Transmission Electron Microscope (TEM) and a particle-size analyzer. The particles show soft ferromagnetic characteristics with definite and moderate saturation magnetization values. The nickel sulfide nanoparticles' in vitro anticancer and antibacterial activities are investigated in free and 5-fluorouracil/penicillin benzathine-loaded forms. The 5-fluorouracil-encapsulation efficiency of the nanoparticles is around 87%, whereas it is above 92% in the case of penicillin benzathine. Both drugs are released slowly in a controlled fashion. The dysprosium-doped nickel sulfide nanoparticles show better anticancer activity, and the efficacy is more significant than the free drug. The nanoparticles are irradiated with a low-power 808 nm laser. The dysprosium-doped nickel sulfide nanoparticles attain a higher temperature on irradiation, i.e., above 59 °C. The photothermal conversion efficiency of this material is determined, and the significance of dysprosium doping is discussed. Contrarily, the undoped nickel sulfide nanoparticles show more significant antibacterial activity. This study presents a novel designed nanoparticle system and the exciting variation of properties on dysprosium doping in nickel sulfide nanoparticles.

Nonselective versus Selective Angioembolization for Trauma Patients with Pelvic Injuries Accompanied by Hemorrhage: A Meta-Analysis

Background and Objectives: Angioembolization has emerged as an effective therapeutic approach for pelvic hemorrhages; however, its exact effect size concerning the level of embolized artery remains uncertain. Therefore, we conducted this systematic review and meta-analysis to investigate the effect size of embolization-related pelvic complications after nonselective angioembolization compared to that after selective angioembolization in patients with pelvic injury accompanying hemorrhage. Materials and Methods: Relevant articles were collected by searching the PubMed, EMBASE, and Cochrane databases until 24 June 2023. Meta-analyses were conducted using odds ratios (ORs) for binary outcomes. Quality assessment was conducted using the risk of bias tool in non-randomized studies of interventions. Results: Five studies examining 357 patients were included in the meta-analysis. Embolization-related pelvic complications did not significantly differ between patients with nonselective and selective angioembolization (OR 1.581, 95% confidence interval [CI] 0.592 to 4.225, I2 = 0%). However, in-hospital mortality was more likely to be higher in the nonselective group (OR 2.232, 95% CI 1.014 to 4.913, I2 = 0%) than in the selective group. In the quality assessment, two studies were found to have a moderate risk of bias, whereas two studies exhibited a serious risk of bias. Conclusions: Despite the favorable outcomes observed with nonselective angioembolization concerning embolization-related pelvic complications, determining the exact effect sizes was limited owing to the significant risk of bias and heterogeneity. Nonetheless, the low incidence of ischemic pelvic complications appears to be a promising result.

Long-Term Outcomes of Endovascular Embolization in a Vein of Galen Aneurysmal Malformation: A Single-Center Experience

BACKGROUND

A vein of Galen aneurysmal malformation (VGAM) is a rare congenital cerebral vascular condition with a high mortality rate if left untreated. This study describes the long-term outcomes of patients with VGAM, who were treated with endovascular embolization.

METHODS

This retrospective analysis focused on VGAM patients who underwent one or more endovascular embolization sessions between January 2008 and December 2022. The study included newborns and children under 18 years. Data encompassed clinical and demographic characteristics, types of endovascular embolization, treatment complications, mortality rates, and long-term outcomes.

RESULTS

Out of 22 VGAM cases, the majority were boys (86.36%), and the average age of the participants was 38 months, ranging from 25 days to 17 years. Endovascular embolization using liquid embolizing agents was the most common intervention (50%), and around 73% of patients underwent multiple sessions. Some patients underwent ventriculoperitoneal shunting (VPS) due to persistent hydrocephalus. In long-term outcomes, four patients (18.2%) showed developmental delays, and 16 patients (72.7%) had a positive outcome.

CONCLUSIONS

Combining endovascular therapy with a comprehensive management strategy significantly reduces mortality rates and improves the possibility of normal neurological development in patients.

Polymeric Microspheres Designed to Carry Crystalline Drugs at Their Surface or Inside Cavities and Dimples

Injectable polymer microparticles with the ability to carry and release pharmacologically active agents are attracting more and more interest. This study is focused on the chemical synthesis, characterization, and preliminary exploration of the utility of a new type of injectable drug-releasing polymer microparticle. The particles feature a new combination of structural and physico-chemical properties: (i) their geometry deviates from the spherical in the sense that the particles have a cavity; (ii) the particles are porous and can therefore be loaded with crystalline drug formulations; drug crystals can reside at both the particle's surfaces and inside cavities; (iii) the particles are relatively dense since the polymer network contains covalently bound iodine (approximately 10% by mass); this renders the drug-loaded particles traceable (localizable) by X-ray fluoroscopy. This study presents several examples. First, the particles were loaded with crystalline voriconazole, which is a potent antifungal drug used in ophthalmology to treat fungal keratitis (infection/inflammation of the cornea caused by penetrating fungus). Drug loading as high as 10% by mass (=mass of immobilized drug/(mass of the microparticle + mass of immobilized drug) × 100%) could be achieved. Slow local release of voriconazole from these particles was observed in vitro. These findings hold promise regarding new approaches to treat fungal keratitis. Moreover, this study can help to expand the scope of the transarterial chemoembolization (TACE) technique since it enables the use of higher drug loadings (thus enabling higher local drug concentration or extended therapy duration), as well as application of hydrophobic drugs that cannot be used in combination with existing TACE embolic particles.

Cu-doped polypyrrole hydrogel with tumor catalyst activity for NIR-II thermo-radiotherapy

Introduction: Radiotherapy (RT) is one of the key methods for treating breast cancer. However, the effect of single RT is often poor because of insufficient deposition of X-rays in tumor sites and radiation resistance induced by the abnormal tumor microenvironment (overexpression of glutathione (GSH)). The development of multifunctional RT sensitizers and synergetic therapeutic strategies is, therefore, a promising area for enhancing the anticancer effect of RT. Methods: In this study, a multifunctional nanozyme hydrogel based on Cu-doped polypyrrole (CuP) was designed to work concertedly with a second near-infrared thermal RT. The CuP-based hydrogel (CH) reached the tumor site when injected in-situ and achieved long-term storage. Results: Once stimulated with 1064-nm laser irradiation, the heated and softened hydrogel system released CuP nanozyme to provide photothermal therapy, thereby inhibiting the repair of DNA damage caused by RT. In addition, CuP with dual nanozyme activity depleted the intracellular GSH to reduce the antioxidant capacity of the tumor. Moreover, CuP converted H₂O₂ to produce ·OH to directly kill the tumor cells, thus enhancing the capability of low-dose RT to inhibit tumor growth. In vivo experiments showed that the CH system used in combination with a low-power 1064-nm laser and low-dose RT (4 Gy) exhibited good synergistic anticancer effects and biological safety. Discussion: As a new light-responsive hydrogel system, CH holds immense potential for radio-sensitization.

Oral membrane-biomimetic nanoparticles for enhanced endocytosis and regulation of tumor-associated macrophage

Enterocyte uptake with high binding efficiency and minor endogenous interference remains a challenge in oral nanocarrier delivery. Enterocyte membrane-biomimetic lipids may universally cooperate with endogenous phosphatidyl choline via a biorthogonal group. In this study, we developed a sophorolipid-associated membrane-biomimetic choline phosphate-poly(lactic-co-glycolic) acid hybrid nanoparticle (SDPN). Aided by physical stability in the gastrointestinal tract and rapid mucus diffusion provided by association with sophorolipid, these nanoparticles show improved endocytosis, driven by dipalmitoyl choline phosphate-phosphatidyl choline interaction as well as its optimized membrane fluidity and rigidity. Luteolin- and silibinin-co-loaded with SDPN alleviated breast cancer metastasis in 4T1 tumor-bearing mice by regulating the conversion of tumor-associated M2 macrophages into the M1 phenotype and reducing the proportion of the M2-phenotype through co-action on STAT3 and HIF-1α. In addition, SDPN reduces angiogenesis and regulates the matrix barrier in the tumor microenvironment. In conclusion, this membrane-biomimetic strategy is promising for improving the enterocyte uptake of oral SDPN and shows potential to alleviate breast cancer metastasis.

Transarterial Embolization and Percutaneous Ablation of Primary and Metastatic Soft Tissue Tumors

Soft tissue tumors (STTs) include a range of benign and malignant tumors originating from soft tissues. Transarterial and percutaneous therapies are image-guided and minimally invasive approaches for managing primary and metastatic STTs. The objective of this review is to discuss transarterial and percutaneous therapies by examining the current literature, including indications, patient selection, safety, and effectiveness. Transarterial therapies (e.g., transarterial bland embolization and transarterial chemoembolization) involve the delivery of either embolic or chemotherapeutic particles using a catheter into arteries feeding the tumor, resulting in localized tumor destruction. Percutaneous therapies (e.g., radiofrequency ablation, cryoablation, irreversible electroporation, laser ablation, and magnetic resonance-guided high-intensity focused ultrasound) involve the delivery of either hot or cold temperatures, electrical current, laser, or ultrasound to specifically target tumor cells. Both therapies have been shown to be safe and effective for reducing morbidity and local control of STTs, specifically in patients who are surgically inoperable or who are unresponsive to conventional therapies. Accurate diagnosis, staging, and histological subtype identification are crucial for treatment selection. A multidisciplinary approach, a thorough understanding of tissue anatomy and surrounding structures, as well as individualized strategies based on assessment are essential for optimal patient care.

Super-Macroporous Pulluan Cryogels as Controlled Active Delivery Systems with Controlled Degradability

Here, super-macroporous cryogel from a natural polysaccharide, pullulan was synthesized using a cryo-crosslinking technique with divinyl sulfone (DVS) as a crosslinker. The hydrolytic degradation of the pullulan cryogel in various simulated body fluids (pH 1.0, 7.4, and 9.0 buffer solutions) was evaluated. It was observed that the pullulan cryogel degradation was much faster in the pH 9 buffer solution than the pH 1.0 and 7.4 buffer solutions in the same time period. The weight loss of the pullulan cryogel at pH 9.0 within 28 days was determined as 31% ± 2%. To demonstrate the controllable drug delivery potential of pullulan cryogels via degradation, an antibiotic, ciprofloxacin, was loaded into pullulan cryogels (pullulan-cipro), and the loading amount of drug was calculated as 105.40 ± 2.6 µg/mg. The release of ciprofloxacin from the pullulan-cipro cryogel was investigated in vitro at 37.5 °C in physiological conditions (pH 7.4). The amount of drug released within 24 h was determined as 39.26 ± 3.78 µg/mg, which is equal to 41.38% ± 3.58% of the loaded drug. Only 0.1 mg of pullulan-cipro cryogel was found to inhibit half of the growing Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) colonies for 10 min and totally eradicated within 2 h by the release of the loaded antibiotic. No significant toxicity was determined on L929 fibroblast cells for 0.1 mg drug-loaded pullulan cryogel. In contrast, even 1 mg of drug-loaded pullulan cryogel revealed slight toxicity (e.g., 66% ± 9% cell viability) because of the high concentration of released drug.

Elastomeric Porous Poly(glycerol sebacate) Methacrylate (PGSm) Microspheres as 3D Scaffolds for Chondrocyte Culture and Cartilage Tissue Engineering

Cartilage defects can be difficult to treat; therefore, tissue engineering of cartilage is emerging as a promising potential therapy. One interesting area of research explores the delivery of cells to the cartilage defect via scaffold-based cell delivery vehicles and microsurgery. This study explores the use of novel poly(glycerol sebacate) methacrylate (PGSm)-polymerised high internal phase emulsion (polyHIPE) microspheres as scaffolds with embedded cells for cartilage tissue engineering. Porous microsphere scaffolds (100 µm-1 mm diameter) were produced from emulsions consisting of water and a methacrylate-based photocurable resin of poly(glycerol sebacate). These resins were used in conjunction with a T-junction fluidic device and an ultraviolet (UV) curing lamp to produce porous microspheres with a tuneable size. This technique produced biodegradable PGSm microspheres with similar mechanical properties to cartilage. We further explore these microspheres as scaffolds for three-dimensional culture of chondrocytes. The microspheres proved to be very efficient scaffolds for primary chondrocyte culture and were covered by a dense extracellular matrix (ECM) network during the culture period, creating a tissue disk. The presence of glycosaminoglycans (GAGs) and collagen-II was confirmed, highlighting the utility of the PGSm microspheres as a delivery vehicle for chondrocytes. A number of imaging techniques were utilised to analyse the tissue disk and develop methodologies to characterise the resultant tissue. This study highlights the utility of porous PGSm microspheres for cartilage tissue engineering.

Nanostructures for prevention, diagnosis, and treatment of viral respiratory infections: from influenza virus to SARS-CoV-2 variants

Viruses are a major cause of mortality and socio-economic downfall despite the plethora of biopharmaceuticals designed for their eradication. Conventional antiviral therapies are often ineffective. Live-attenuated vaccines can pose a safety risk due to the possibility of pathogen reversion, whereas inactivated viral vaccines and subunit vaccines do not generate robust and sustained immune responses. Recent studies have demonstrated the potential of strategies that combine nanotechnology concepts with the diagnosis, prevention, and treatment of viral infectious diseases. The present review provides a comprehensive introduction to the different strains of viruses involved in respiratory diseases and presents an overview of recent advances in the diagnosis and treatment of viral infections based on nanotechnology concepts and applications. Discussions in diagnostic/therapeutic nanotechnology-based approaches will be focused on H1N1 influenza, respiratory syncytial virus, human parainfluenza virus type 3 infections, as well as COVID-19 infections caused by the SARS-CoV-2 virus Delta variant and new emerging Omicron variant.

Mild-Temperature Responsive Nanocatalyst for Controlled Drug Release and Enhanced Catalytic Therapy

Owing to the advantages of the in situ production of toxic agents through catalytic reactions, nanocatalytic therapy has arisen as a highly potential strategy for cancer therapeutics in recent years. However, the insufficient amount of endogenous hydrogen peroxide (H₂O₂) in the tumor microenvironment commonly limits their catalytic efficacy. Here, we employed carbon vesicle nanoparticles (CV NPs) with high near-infrared (NIR, 808 nm) photothermal conversion efficiency as carriers. Ultrafine platinum iron alloy nanoparticles (PtFe NPs) were grown in situ on the CV NPs, where the highly porous nature of the resultant CV@PtFe NPs was employed to encapsulate a drug, β-lapachone (La), and phase-change material (PCM). As a multifunctional nanocatalyst CV@PtFe/(La-PCM) NPs can exhibit a NIR-triggered photothermal effect and activate cellular heat shock response, which upregulates the downstream NQO1 via HSP70/NQO1 axis to facilitate bio-reduction of the concurrently melted and released La. Moreover, sufficient oxygen (O₂) is supplied by CV@PtFe/(La-PCM) NPs catalyzed at the tumor site to reinforce the La cyclic reaction with abundant H₂O₂ generation. This promotes the bimetallic PtFe-based nanocatalysis, which breaks H₂O₂ down into highly toxic hydroxyl radicals (•OH) for catalytic therapy. Our results show that this multifunctional nanocatalyst can be used as a versatile synergistic therapeutic agent with NIR-enhanced nanocatalytic tumor therapy by tumor-specific H₂O₂ amplification and mild-temperature photothermal therapy, which holds promising potential for targeted cancer treatment. STATEMENT OF SIGNIFICANCE: We present a multifunctional nanoplatform with mild-temperature responsive nanocatalyst for controlled drug release and enhanced catalytic therapy. This work aimed at not only reduce the damage to normal tissues caused by photothermal therapy, but also improves the efficiency of nanocatalytic therapy by stimulating endogenous H₂O₂ production through photothermal heat. In vitro and in vivo confirmed that CV@PtFe/(La-PCM) NPs exhibited powerful and overall antitumor effects. This formulation may provide an alternative strategy for the development of the mild- photothermal enhanced nanocatalytic therapy effect in solid tumor.

Preparation of Biocompatible Manganese Selenium-Based Nanoparticles with Antioxidant and Catalytic Functions

The specificity of the tumor microenvironment (TME) severely limits the effectiveness of tumor treatment. In this study, we prepared a composite nanoparticle of manganese dioxide and selenite by a one-step redox method, and their stability under physiological conditions was improved with a bovine serum protein modification to obtain MnO₂/Se-BSA nanoparticles (SMB NPs). In the SMB NPs, manganese dioxide and selenite endowed the SMB NPs with acid-responsive and catalytic, and antioxidant properties, respectively. The weak acid response, catalytic activity, and antioxidant properties of composite nanoparticles were verified experimentally. Moreover, in an in vitro hemolysis assay, different concentrations of nanoparticles were incubated with mouse erythrocytes, and the hemolysis ratio was less than 5%. In the cell safety assay, the cell survival ratio was as high as 95.97% after the co-culture with L929 cells at different concentrations for 24 h. In addition, the good biosafety of composite nanoparticles was verified at the animal level. Thus, this study helps to design high-performance and comprehensive therapeutic reagents that are responsive to the hypoxia, weak acidity, hydrogen peroxide overexpression nature of TME and overcome the limitations of TME.

Investigating the effect of electrosprayed alginate/PVA beads size on the microbial growth kinetics: Phenol biodegradation through immobilized activated sludge

The presence of cyclic organic compounds, including phenol, in the wastewater of many industries has made phenol removal an important issue. Meanwhile, the biological methods of removing phenol have attracted the attention of researchers in recent years. Recently, the use of immobilized microbial cells is proposed as a new approach in industrial wastewater treatment. In this research, the aim is to study the effect of immobilized beads size on the phenol biodegradation efficiency and specific microbial growth rate. For this purpose, electrospray technique was used to immobilize activated sludge in hybrid matrix of alginate and polyvinyl alcohol (PVA). The fabricated alginate/PVA beads were characterized using Fourier transform infrared spectroscopy (FTIR). Evaluation of the results related to the free and immobilized cell systems in the shake flask experiments showed that at low phenol concentrations the immobilized cell system had the same performance as the free cell system, while the immobilized cell system at higher concentrations had a better performance in removing phenol so that at a concentration of 2000 mg/L, removal percentage has increased from 15% to 25-34%. On the other hand, in this survey, the kinetic behavior of activated sludge was in good agreement with Haldane's equation. Moreover, the maximum specific growth rate was measured 0.033 and 0.041 (h^-1) beside 544 and 636 mg/L substrate inhibition constant, for free and immobilized cell systems, respectively. This result shows that the phenol biodegradation has been improved by using the cell immobilization technique especially with applying the smaller beads, which is due to improved mass transfer and microbial cell protection from harsh environments.

Glucose oxidase-loaded colloidal stable WS2 nanobowls for combined starvation/photothermal therapy of colorectal tumors

Glucose is used as an important nutrient to support cell growth. The glucose oxidase (GOx) can transform glucose into gluconic acid and toxic H₂O₂, which can be used for tumor starvation therapy. However, the leakage of GOx may cause severe side effects to the normal tissue. To prevent the accidental leakage of GOx, this study proposes the chemical modification of GOx on the photothermal transducing agent surface, to realize the safe and combined starvation and photothermal therapy of colorectal tumors. Polyvinylpyrrolidone (PVP)-modified WS₂ nanobowls (WS₂-PVP) as a photothermal transducing agent were produced using a one-pot preparation method. Then, α-lipoic acid (LA) molecules were immobilized at the sulfur-deficient sites on the surface of WS₂ nanobowls to afford the chemical loading of GOx through amide bonds. Under the irradiation of a near-infrared laser (808 nm), thermal energy is generated by WS₂ to kill colorectal cancer cells locally. The photothermal conversion efficiency of WS₂-PVP-LA was 27.2%. This study is anticipated to open up an alternative avenue for the rational design of multifunctional nanotherapeutics for tumor therapy.

Rheological Properties of Non-Adhesive Embolizing Compounds-The Key to Fine-Tuning Embolization Process-Modeling in Endovascular Surgery

The study of polymers' rheological properties is of paramount importance both for the problems of their industrial production as well as for their practical application. Two polymers used for embolization of arteriovenous malformations (AVMs) are studied in this work: Onyx-18^® and Squid-12^®. Viscosity curve tests and computational fluid dynamics (CFD) were used to uncover viscosity law as a function of shear rate as well as behavior of the polymers in catheter or pathological tissue models. The property of thermal activation of viscosity was demonstrated, namely, the law of dependence of viscosity on temperature in the range from 20 °C to 37 °C was established. A zone of viscosity nonmonotonicity was identified, and a physical interpretation of the dependence of the embolic polymers' viscosity on the shear rate was given on the basis of Cisco's model. The obtained empirical constants will be useful for researchers based on the CFD of AVMs. A description of the process of temperature activation of the embolic polymers' viscosity is important for understanding the mechanics of the embolization process by practicing surgeons as well as for producing new prospective embolic agents.

Sodium alginate hydrogel containing platelet-rich plasma for wound healing

Recently, the healing of chronic wounds such as extensive burns has become a serious and intractable clinical problem. Avoiding wound infection and retaining an appropriate level of moisture around wounds are significant challenges in wound care. Herein, a dual-network hydrogel composed of sodium alginate (SA) and platelet-rich plasma (PRP) was designed to facilitate the wound healing. The preparation of hydrogel was achieved through a simple one-step thrombin activation process. The morphological characterization results revealed the three-dimensional network structure of the hydrogel. Then, certain levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) were detected in phosphate buffer solution (PBS) cultured hydrogel, which led to the possibility of cell proliferation and vascular regeneration. When topically applied to the wound skin of rats, the hydrogel presented high wound closure effectiveness. In conclusion, this strategy provides a simple and feasible approach to overcoming the shortcomings of conventional wound dressings.

Establishment of ultrasound-responsive SonoBacteriaBot for targeted drug delivery and controlled release

Bacteria-driven biohybrid microbots have shown great potential in caⁿcer treatment. However, how precisely controlling drug release at the tumor site is still an issue. To overcome the limitation of this system, we proposed the ultrasound-responsive SonoBacteriaBot (DOX-PFP-PLGA@EcM). Doxorubicin (DOX) and perfluoro-n-pentane (PFP) were encapsulated in polylactic acid-glycolic acid (PLGA) to form ultrasound-responsive DOX-PFP-PLGA nanodroplets. Then, DOX-PFP-PLGA@EcM is created by DOX-PFP-PLGA amide-bonded to the surface of E. coli MG1655 (EcM). The DOX-PFP-PLGA@EcM was proved to have the characteristics of high tumor-targeting efficiency, controlled drug release capability, and ultrasound imaging. Based on the acoustic phase change function of nanodroplets, DOX-PFP-PLGA@EcM enhance the signal of US imaging after ultrasound irradiation. Meanwhile, the DOX loaded into DOX-PFP-PLGA@EcM can be released. After being intravenously injected, DOX-PFP-PLGA@EcM can efficiently accumulate in tumors without causing harm to critical organs. In conclusion, the SonoBacteriaBot has significant benefits in real-time monitoring and controlled drug release, which has significant potential applications for therapeutic drug delivery in clinical settings.

NIR-II fluorescence microscopic bioimaging for intrahepatic angiography and the early detection of Echinococcus multilocularis microlesions

Hepatic alveolar echinococcosis (HAE) is caused by the metacestode of Echinococcus multilocularis, which shows characteristics of malignant tumors with high mortality. However, traditional diagnostic imaging methods are still not sufficient for the recognition of HAE microlesions in the early stages. Near-infrared-II (900-1700 nm, NIR-II) fluorescence microscopic imaging (NIR-II-FMI) has shown great potential for biomedical detection. A novel type of negative target imaging method based on NIR-II-FMI with the assistance of indocyanine green (ICG) was explored. Then, NIR-II-FMI was applied to the early detection of HAE for the first time. The negative targeting NIR-II fluorescence imaging of HAE-infected mice at different stages with the assistance of ICG under 808 nm of laser irradiation was obtained. Especially, HAE microlesions at the early stage were detected clearly. Moreover, clear intrahepatic angiography was achieved under the same NIR-II-FMI system.

Progress of Electrospun Nanofibrous Carriers for Modifications to Drug Release Profiles

Electrospinning is an advanced technology for the preparation of drug-carrying nanofibers that has demonstrated great advantages in the biomedical field. Electrospun nanofiber membranes are widely used in the field of drug administration due to their advantages such as their large specific surface area and similarity to the extracellular matrix. Different electrospinning technologies can be used to prepare nanofibers of different structures, such as those with a monolithic structure, a core-shell structure, a Janus structure, or a porous structure. It is also possible to prepare nanofibers with different controlled-release functions, such as sustained release, delayed release, biphasic release, and targeted release. This paper elaborates on the preparation of drug-loaded nanofibers using various electrospinning technologies and concludes the mechanisms behind the controlled release of drugs.

Targeted Multifunctional Nanoplatform for Imaging-Guided Precision Diagnosis and Photothermal/Photodynamic Therapy of Orthotopic Hepatocellular Carcinoma

Background

Effective theranostic of hepatocellular carcinoma (HCC) in an early-stage is imminently demanded to improve its poor prognosis. Combination of the near-infrared (NIR) photoacoustic imaging (PAI) and fluorescence imaging (FLI) can provide high temporospatial resolution, outstanding optical contrast, and deep penetration and thus is promising for accurate and sensitive HCC diagnosis.

Methods

A versatile CXCR4-targeted Indocyanine green (ICG)/Platinum (Pt)-doped polydopamine melanin-mimic nanoparticle (designated ICG/Pt@PDA-CXCR4, referred to as IPP-c) is synthesized as an HCC-specific contrast agent for high-resolution precise diagnostic PAI/FLI and optical imaging-guided targeted photothermal therapy (PTT)/photodynamic therapy (PDT) of orthotopic small hepatocellular carcinoma (SHCC).

Results

The multifunctional targeted nanoparticle yields superior HCC specificity, high imaging contrast in both PAI and FLI, good stability, reliable biocompatibility, effective singlet oxygen generation and superior photothermal conversion efficiency (PCE, 58.7%) upon 808-nm laser irradiation. The targeting ability of IPP-c was validated in in vitro experiments on selectively killing the CXCR4-overexpressing HCC cells. Moreover, we test the efficient dual-modal optical precision diagnosis properties of IPP-c via in vivo experiments on targeted particle accumulation in an early-stage SHCC mouse model (tumor diameter about 1.2 mm). Then, under the guidance of real-time optical imaging, effective and mini-invasive PTT/PDT of orthotopic SHCCs were demonstrated without damaging adjacent liver tissues or other major organs.

Conclusion

This study presented a multifunctional CXCR4-targeted nanoparticle to conduct effective and mini-invasive phototherapeutics of orthotopic SHCCs via the real-time quantitative guidance by optical imaging, which provided a new perception for building a versatile targeted nanoplatform for phototheranostics of early-stage HCC.

Tungsten disulfide nanoflowers with multi-nanoenzyme activities for the treatment of acute liver injury

In this study, polyvinyl pyrrolidone modified tungsten disulfide (WS₂-PVP) nanoflower was synthesized using a simple and effective one-pot method. Owing to the surface polyvinyl pyrrolidone (PVP) modification, WS₂-PVP nanoflowers showed excellent colloidal stability in different circumstances, which can be well dispersed in water, saline, and cell culture medium. Meanwhile, the WS₂-PVP nanoflowers have a good biocompatibility both in vitro and in vivo. Further studies confirmed that the WS₂-PVP nanoflowers have the ability of simulating catalase, superoxide dismutase and glutathione peroxidase enzymes and scavenging reactive oxygen species (ROS). Therefore, WS₂-PVP nanoflowers were used to treat reactive oxygen species-related diseases, which showed the cell protection effect and significantly improved the treatment results of acute liver injury on mice. We hope that our findings will facilitate the development of nanomaterials with multiple enzymatic mimicking properties and further clinical application of tungsten-based ROS scavengers in biomedical therapy and research.

Emerging Polymer Materials in Trackable Endovascular Embolization and Cell Delivery: From Hype to Hope

Minimally invasive endovascular embolization is a widely used clinical technique used for the occlusion of blood vessels to treat various diseases. Different occlusive agents ranging from gelatin foam to synthetic polymers such as poly(vinyl alcohol) (PVA) have been commercially used for embolization. However, these agents have some drawbacks, such as undesired toxicity and unintended and uncontrolled occlusion. To overcome these issues, several polymer-based embolic systems are under investigation including biocompatible and biodegradable microspheres, gelling liquid embolic with controlled occlusive features, and trackable microspheres with enhanced safety profiles. This review aims to summarize recent advances in current and emerging polymeric materials as embolization agents with varying material architectures. Furthermore, this review also explores the potential of combining injectable embolic agents and cell therapy to achieve more effective embolization with the promise of outstanding results in treating various devastating diseases. Finally, limitations and challenges in developing next-generation multifunctional embolic agents are discussed to promote advancement in this emerging field.