Synthesis and in vitro evaluation of pH-sensitive magnetic nanocomposites as methotrexate delivery system for targeted cancer therapy

A functionalized cell membrane biomimetic nanoformulation based on layered double hydroxide for combined tumor chemotherapy and sonodynamic therapy

The development of nanoformulations with simple compositions that can exert targeted combination therapy still remains a great challenge in the area of precision cancer nanomedicine. Herein, we report the design of a multifunctional nanoplatform based on methotrexate (MTX)-loaded layered double hydroxide (LDH) coated with chlorin e6 (Ce6)-modified MCF-7 cell membranes (CMM) for combined chemo/sonodynamic therapy of breast cancer. LDH nanoparticles were in situ loaded with MTX via coprecipitation, and coated with CMM that were finally functionalized with phospholipid-modified Ce6. The created nanoformulation of LDH-MTX@CMM-Ce6 displays good colloidal stability under physiological conditions and can release MTX in a pH-dependent manner. We show that the formulation can homologously target breast cancer cells, and induce their significant apoptosis through arresting the cell cycle via cooperative MTX-based chemotherapy and ultrasound (US)-activated sonodynamic therapy. The assistance of US can not only trigger sonosensitizer Ce6 to produce reactive oxygen species, but also enhance the cellular uptake of LDH-MTX@CMM-Ce6 via an acoustic cavitation effect. Upon intravenous injection and US irradiation, LDH-MTX@CMM-Ce6 displays an admirable antitumor performance towards a xenografted breast tumor mouse model. Furthermore, the modification of Ce6 on the CMM endows the LDH-based nanoplatform with fluorescence imaging capability. The developed LDH-based nanoformulation here provides a general intelligent cancer nanomedicine platform with simple composition and homologous targeting specificity for combined chemo/sonodynamic therapy and fluorescence imaging of tumors.

Recovery of rare earth elements from mine wastewater using alginate microspheres encapsulated with zeolitic imidazolate framework-8

There is increasing demand and interest in efficient methods for the recovery of rare earth elements (REEs) from wastewater because of the growing concerns associated with the negative impacts of REEs-rich waste discharged on pristine ecosystems. Here, we designed a ZIF-8@ALG composite hydrogel by encapsulating zeolitic imidazolate frameworks-8 (ZIF-8) into sodium alginate and poly (vinyl alcohol) double cross-linked networks (ALG) for the recovery of REEs from mine wastewater. ZIF-8@ALG showed exceptional REEs adsorption performance with the most superior separation factor (Ho/Mn) of 597.5. For the REEs considered, the ZIF-8@ALG composite exhibited a preference for heavy REEs with high adsorption efficiencies (65.3 ∼ 97.2%) and distribution coefficients (2045.5 ∼ 28500.0 mL·g-1). Adsorption involved a combination of electrostatic attraction, complexation and ion exchange mechanisms. REEs adsorbed on ZIF-8@ALG could also be desorbed using sodium citrate via ion-exchange and complexation, thus achieving efficient REEs recovery. In addition, ZIF-8@ALG was stable and reusable, maintaining effective adsorption in wastewater over four consecutive cycles, where the optimal adsorption efficiency reached 80.0%. Overall, this study provided an effective and feasible method for the recovery of REEs in mine wastewater, and confirmed that ZIF-8-based materials have significant potential for REEs recovery applications in wastewater engineering treatment.

Antitumoral-Embedded Biopolymeric Spheres for Implantable Devices

The bioactive surface modification of implantable devices paves the way towards the personalized healthcare practice by providing a versatile and tunable approach that increase the patient outcome, facilitate the medical procedure, and reduce the indirect or secondary effects. The purpose of our study was to assess the performance of composite coatings based on biopolymeric spheres of poly(lactide-co-glycolide) embedded with hydroxyapatite (HA) and methotrexate (MTX). Bio-simulated tests performed for up to one week evidenced the gradual release of the antitumor drug and the biomineralization potential of PLGA/HA-MTX sphere coatings. The composite materials proved superior biocompatibility and promoted enhanced cell adhesion and proliferation with respect to human preosteoblast and osteosarcoma cell lines when compared to pristine titanium.

Advances in drug delivery systems, challenges and future directions

Advances in molecular pharmacology and an improved understanding of the mechanism of most diseases have created the need to specifically target the cells involved in the initiation and progression of diseases. This is especially true for most life-threatening diseases requiring therapeutic agents which have numerous side effects, thus requiring accurate tissue targeting to minimize systemic exposure. Recent drug delivery systems (DDS) are formulated using advanced technology to accelerate systemic drug delivery to the specific target site, maximizing therapeutic efficacy and minimizing off-target accumulation in the body. As a result, they play an important role in disease management and treatment. Recent DDS offer greater advantages when compared to conventional drug delivery systems due to their enhanced performance, automation, precision, and efficacy. They are made of nanomaterials or miniaturized devices with multifunctional components that are biocompatible, biodegradable, and have high viscoelasticity with an extended circulating half-life. This review, therefore, provides a comprehensive insight into the history and technological advancement of drug delivery systems. It updates the most recent drug delivery systems, their therapeutic applications, challenges associated with their use, and future directions for improved performance and use.

Magnetic Fe3O4@ZIF-8 nanoparticles as a drug release vehicle: pH-sensitive release of norfloxacin and its antibacterial activity

Metal-organic frameworks (MOFs) have a high specific surface area and inherent biodegradability due to their unique structure and composition. As well, owing to the properties of nanomaterials and especially their magnetic features, Fe₃O₄ nanoparticles and MOFs composite materials have great potential in the design and application of drug release. The present work: firstly, investigated norfloxacin loading in magnetic metal organic framework (Fe₃O₄@ZIF-8); and secondly, studied the release of norfloxacin and its antibacterial activity. Results showed the release efficiencies reached 97 % at 310 K after 84 h (pH 7.4). Drug release behavior was tested at various pH levels and it was found that Fe₃O₄@ZIF-8 has pH-sensitive properties. Furthermore, the release model calculation illustrated that the release process fitted well to the Bhaskar model. The magnetic properties of Fe₃O₄@ZIF-8 confirmed that the composite has potential application for a targeted drug delivery system. The mechanism of pH-responsive norfloxacin release was combined with diffusion, ion exchange and electrostatic repulsion. Furthermore, the antibacterial activities of Fe₃O₄@ZIF-8 and NOR-Fe₃O₄@ZIF-8 were tested against Escherichia coli. Results showed that Fe₃O₄@ZIF-8 had good biocompatibility while NOR-Fe₃O₄@ZIF-8 can deter or inhibit the actions of microorganisms.

Construction of pH-responsive polydopamine coated magnetic layered hydroxide nanostructure for intracellular drug delivery

In recent years, using magnetic nanocomposites for controlled release of drugs and target-specific drug delivery has great potential in exploring a new method for cancer chemotherapy. Nevertheless, the low loading rate of insoluble drugs greatly restricts their efficacy and clinical application. Here, an efficient magnetic nanostructure combining Fe₃O₄ nanoparticles and layered double hydroxide (LDH) was developed and used for tumor cell inhibition. LDH was first deposited on Fe₃O₄ nanoparticles (Fe₃O₄@LDH), curcumin (Cur) was then loaded and polydopamine (PDA) eventually formed a PDA-coating on Fe₃O₄@Cur-LDH via self-polymerization. The Fe₃O₄@Cur-LDH/PDA nanostructure showed a suitable nano-meter size, excellent magnetic property, and high drug loading rate (up to 38 %). In vitro release results implied that Fe₃O₄@Cur-LDH/PDA nanostructure had good pH-responsive performance and excellent controlled-release behaviors due to the introduction of PDA. The cellular experiments demonstrated that Fe₃O₄@Cur-LDH/PDA nanostructure had good biocompatibility. In addition, Fe₃O₄@Cur-LDH/PDA entered into the cells mainly through endocytosis and had excellent inhibition on HepG2 cell viability in a concentration-dependent manner. Therefore, Fe₃O₄@Cur-LDH/PDA nanostructure has a prospective application in cancer therapy as a controlled drug delivery system.

Synthesis and characterization of magnetic polymeric nanocomposites for pH-sensitive controlled release of methotrexate

As one of the well-known anticancer drugs, methotrexate (MTX) has been limited in clinical application due to its side effects on normal tissues. This study focused on the one-step hydrothermal synthesis and in vitro evaluation of Fe₃O₄/RGO-PEI as MTX carriers for targeted anticancer therapy. In which, the Fe₃O₄ provided magnetic response properties; RGO acted as a stage for Fe₃O₄ loading and improved the dispersion of Fe₃O₄; polyethylenimine (PEI) was used as a surface modifier and a storehouse for MTX. The prepared Fe₃O₄/RGO-PEI nanocomposites exhibited a suitable size, good stability and magnetic responsibility. And the MTX loading content and loading efficiency were calculated to be 26.6% and 90.5%, respectively. What's more, due to the diffusion and dissolution of PEI, the Fe₃O₄/RGO-PEI-MTX exhibited excellent pH-sensitivity, the values of MTX release rate (%) within 48 h at pH 5.8 and 4.0 were 64.3% and 87.4%, respectively. Furthermore, MTT assays in cancer cells (HepG2) and normal cells (HUVEC) demonstrated that Fe₃O₄/RGO-PEI-MTX exhibited high anticancer activity while low toxicity to normal cells, and also the Fe₃O₄/RGO-PEI composites were practically non-toxic. Thus, our results revealed that Fe₃O₄/RGO-PEI-MTX would be a competitive candidate for targeted delivery and controlled release of MTX.

D-mannose functionalized MgAl-LDH/Fe-MOF nanocomposite as a new intelligent nanoplatform for MTX and DOX co-drug delivery

Commonly the directly administered chemotherapy drugs lack targeting in tumor treatment. Thus, trying to improve cancer treatment efficiency led us to design a new intelligent system for cancer treatment. Considering these, in the current work, at first, the 2-aminoterephthalic acid (NH₂-BDC) intercalated layered double hydroxides (MgAl-(NH₂-BDC) LDH) were synthesized simply. Afterward, the in situ growth of the iron-based metal-organic frameworks in the presence of MgAl-(NH₂-BDC) LDH occurred (MgAl-LDH/Fe-MOF). In the end, the reaction of MgAl-LDH/Fe-MOF with D-mannose (D-Man) achieved the MgAl-LDH/Fe-MOF/D-Man ternary hybrid nanostructure. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis confirmed the formation of the monodisperse Fe-MOF with nanosize in the presence of MgAl-LDH. Importantly, methotrexate (MTX) and doxorubicin (DOX) entrapment efficiency reached respectively about 28 wt% and 21% for MgAl-LDH/Fe-MOF/D-Man. The in vitro drug release experiments revealed a higher drug release at pH 5.0 in comparison with pH 7.4 which revealed its promising potential for anticancer drug delivery applications. Bioassay results revealed that the co-drug-loaded MgAl-LDH/Fe-MOF/D-Man has higher cytotoxicity on MDA-MB 231 cells. At last, fluorescence microscopy and flow cytometric analysis confirmed the successful uptake of MgAl-LDH/Fe-MOF/D-Man into MDA-MB 231 cell lines, as well as its bioimaging potential. A survey in the published literature approved that this work is the first report on the evaluation of the MgAl-LDH/Fe-MOF/D-Man for targeted co-delivery of both MTX and DOX. Finally, results collectively demonstrate the importance of the biocompatible MgAl-LDH/Fe-MOF/D-Man as a hopeful candidate for biomedicinal applications from the targeted co-drug delivery and bioimaging potential viewpoints.

Lactobionic acid-modified thymine-chitosan nanoparticles as potential carriers for methotrexate delivery

In order to achieve efficient delivery of methotrexate (MTX), thymine-chitosan nanoparticles (Thy-Cs NPs) were prepared, and further decorated with lactobionic acid (LA) to obtain tumor-targeting nanoparticles (LA-Thy-Cs NPs). These nanoparticles possessed a regular spherical structure with the average size about 190-250 nm and narrow size distribution, which were kinetically stable in the physiological environment. Due to electrostatic interactions and multiple hydrogen-bonding interactions between MTX and carriers, MTX was loaded into Thy-Cs NPs with high drug loading content (~20%). MTX release from Thy-Cs NPs was significantly accelerated in the mildly acidic environment due to the destruction of two types of non-covalent interactions. In vitro cell experiments demonstrated that LA-Thy-Cs NPs could be efficiently internalized into hepatoma carcinoma cells, leading to higher cytotoxicity. Moreover, MTX-loaded LA-Thy-Cs NPs performed an enhanced growth inhibition in three-dimensional multicellular tumor spheroids. Thus, the LA decorated thymine-chitosan nanocarriers can be a promising candidate for efficient delivery of MTX.

Preparation, surface functionalization and application of Fe3O4 magnetic nanoparticles

This paper reviews recent developments in the preparation, surface functionalization, and applications of Fe₃O₄ magnetic nanoparticles. Especially, it includes preparation methods (such as electrodeposition, polyol methods, etc.), organic materials (such as polymers, small molecules, surfactants, biomolecules, etc.) or inorganic materials (such as silica, metals, and metal oxidation/sulfide, functionalized coating of carbon surface, graphene, etc.) and its applications (such as magnetic separation, protein fixation, magnetic catalyst, environmental treatment, medical research, etc.). In the end, some existing challenges and possible future trends in the field were discussed.

2D Nanomaterials for Cancer Theranostic Applications

2D nanomaterials with unique nanosheet structures, large surface areas, and extraordinary physicochemical properties have attracted tremendous interest. In the area of nanomedicine, research on graphene and its derivatives for diverse biomedical applications began as early as 2008. Since then, many other types of 2D nanomaterials, including transition metal dichalcogenides, transition metal carbides, nitrides and carbonitrides, black phosphorus nanosheets, layered double hydroxides, and metal-organic framework nanosheets, have been explored in the area of nanomedicine over the past decade. In particular, a large surface area makes 2D nanomaterials highly efficient drug delivery nanoplatforms. The unique optical and/or X-ray attenuation properties of 2D nanomaterials can be harnessed for phototherapy or radiotherapy of cancer. Furthermore, by integrating 2D nanomaterials with other functional nanoparticles or utilizing their inherent physical properties, 2D nanomaterials may also be engineered as nanoprobes for multimodal imaging of tumors. 2D nanomaterials have shown substantial potential for cancer theranostics. Herein, the latest progress in the development of 2D nanomaterials for cancer theranostic applications is summarized. Current challenges and future perspectives of 2D nanomaterials applied in nanomedicine are also discussed.

Surface modification of fluorescent Tb3+-doped layered double hydroxides with hyperbranched polymers through host-guest interaction

The preparation of fluorescent inorganic-organic polymer composites for biomedical applications has become one of the most interest research focuses recently. In this work, we reported a novel method for the preparation of Tb³⁺-doped luminescent layered double hydroxides (LDHs) based composites by taken advantage of a one-pot supramolecular chemistry. The adamantane can be immobilized on the surface of Tb³⁺-doped LDHs to obtain LDH-Ad, which could be further utilized for modified by the β-cyclodextrin (β-CD) containing hyperbranched polyglycerols (β-CD-HPG) through the host-guest interaction. Based on the characterization results, we demonstrated that the hyperbranched polyglycerol could be facilely introduced on these fluorescent Tb³⁺-doped LDHs through the method described in this work. The obtained Tb³⁺-doped LDHs based polymer composites (LDHs-β-CD-HPG) display improved water dispersibility and still maintain their fluorescence. The results based on various biological assays suggest that LDHs-β-CD-HPG polymer composites are of low cytotoxicity and their cell uptake behavior can be effectively traced using confocal laser imaging. All of the above results demonstrated that the fluorescent Tb³⁺-doped LDHs based polymer composites could be effectively surface modified with hydrophilic hyperbranched polymers through a one-pot facile host-guest interaction and the resultant fluorescent composites are of excellent physicochemical properties and display great potential for biomedical applications. This novel surface modification method should also be important for fabrication of other multifunctional composites and therefore great advanced the development of biomedical applications of fluorescent LDHs based polymer composites and related materials.

Targeting Strategies for the Combination Treatment of Cancer Using Drug Delivery Systems

Cancer cells have characteristics of acquired and intrinsic resistances to chemotherapy treatment-due to the hostile tumor microenvironment-that create a significant challenge for effective therapeutic regimens. Multidrug resistance, collateral toxicity to normal cells, and detrimental systemic side effects present significant obstacles, necessitating alternative and safer treatment strategies. Traditional administration of chemotherapeutics has demonstrated minimal success due to the non-specificity of action, uptake and rapid clearance by the immune system, and subsequent metabolic alteration and poor tumor penetration. Nanomedicine can provide a more effective approach to targeting cancer by focusing on the vascular, tissue, and cellular characteristics that are unique to solid tumors. Targeted methods of treatment using nanoparticles can decrease the likelihood of resistant clonal populations of cancerous cells. Dual encapsulation of chemotherapeutic drug allows simultaneous targeting of more than one characteristic of the tumor. Several first-generation, non-targeted nanomedicines have received clinical approval starting with Doxil® in 1995. However, more than two decades later, second-generation or targeted nanomedicines have yet to be approved for treatment despite promising results in pre-clinical studies. This review highlights recent studies using targeted nanoparticles for cancer treatment focusing on approaches that target either the tumor vasculature (referred to as 'vascular targeting'), the tumor microenvironment ('tissue targeting') or the individual cancer cells ('cellular targeting'). Recent studies combining these different targeting methods are also discussed in this review. Finally, this review summarizes some of the reasons for the lack of clinical success in the field of targeted nanomedicines.

Synthesis of Naked-eye Detectable Fluorescent 2H-chromen-2-One 2, 6-Dicyanoanilines: Effect of Substituents and pH on Its Luminous Behavior

A variety of new coumarin derivatives containing C-4 bridged 2,6-dicyanoanilines (4a-4d) were synthesized via multicomponent one pot approach. These novel sensors were characterized by spectral analysis and a series of pH sensing fluorescence studies were performed, the results indicating that the sensors are highly selective and more effective at various pH. The fluorescence colour changes at different pH could be directly detected by naked eyes.

Computational investigation of metal organic frameworks for storage and delivery of anticancer drugs

The potential of metal organic frameworks (MOFs) as binary drug carriers was computationally investigated for storage and delivery of two anticancer drug molecules, methotrexate (MTX) and 5-fluorouracil (5-FU).