Preparation of barium sulfate/polymer hybrid nanoparticles from Bunte salt precursors

Barium sulfate suspensions are commonly used as contrast agents for improving the resolution of X-ray imaging. However, current limitations are rapid contrast washout and low stability in water. Polymer nanoparticles are synthesized by copolymerizing vinyl benzyl thiosulfate with methyl methacrylate in a miniemulsion by free-radical polymerization. BaSO4 is then formed by the hydrolysis of thiosulfate-functionalized nanoparticles, leading to the production of sulfate ions, which react subsequently with Ba2+ in dispersion.

Synthesis of Lead(II) Carbonate-Containing Nanoparticles Using Ultrasonication or Microwave Irradiation

We report on the synthesis of lead(II) carbonate-containing nanoparticles using the polyol process under high-energy ultrasound or microwave irradiation as alternate energization methods. Five carbonate source precursors are used in the reaction, and the precipitation reactions generate four different crystal products, depending on the precursor. More alkaline precursors produce the hydroxy-carbonate structures (abellaite, or its potassium analog, and hydrocerussite), while the less alkaline precursors produce the simple carbonate structure (cerussite). Ultrasonication or microwave irradiation during the arrested precipitation ensures the formation of nanoparticles <100 nm in diameter in a mostly single crystalline phase in all cases, bar one. The products were characterized by powder X-ray diffraction, dynamic light scattering, electron microscopy, infrared spectroscopy, and thermal analysis. These nanoparticles are targeted as X-ray contrast agents for biological imaging, particularly of fine vasculature where small particle size is essential.

Barium Sulfate Nanocomposites for Bioimaging and Chemo-photothermal Therapy of Physiologically Aggravated Lung Adenocarcinoma Cells

Cancer is a complex disease that displays physiomorphological transformation in different surrounding microenvironments. Therefore, the single treatment modalities are relatively less effective, and their efficiency varies with tumor cell physiology, leading to the development of tumor resistance. Combinatorial therapeutic approaches, such as chemo-photothermal therapy, are promising for efficiently mitigating tumor progression irrespective of cancer physiology. Nanotechnology has played a significant role in this regard. Therefore, the present study reports the synthesis of poly(acrylic acid)-tetraethylene glycol (PAA-TEG)-coated BaSO4 nanoparticles (NPs) with enhanced solubility, dispersibility, and X-ray attenuation. Next, nanocomposites (NCs) are synthesized by loading BaSO4 NPs with the therapeutic drug triiodobenzoic acid (Tiba) and the photosensitizer IR780 using a lipid coating. These fabricated NCs are analyzed for dual-modal imaging (fluorescence and X-ray-based imaging) properties and chemo-phototherapeutic ability against two-dimensional (2D) and three-dimensional (3D) cultures of A549 cells. Furthermore, A549 cells are morphologically and physiologically aggravated into potent malignant cells using tobacco leaf extract (TE), and the variation in the therapeutic effect of NCs compared to cisplatin is determined. The synthesized NCs display enhanced encapsulation and excellent synergistic anticancer activity through the generation of reactive oxygen species (ROS), mitochondrial damage, and genotoxicity. Also, the NCs are more potent in inhibiting cancer cell growth than cisplatin, and their impact is unaltered in the presence or absence of TE pretreatment of A549 cells. The present study holds significant potential for various theranostic applications, which are highly desired for laparoscopic image-guided lung cancer therapy.

CT-Visible Microspheres Enable Whole-Body In Vivo Tracking of Injectable Tissue Engineering Scaffolds

Targeted delivery and retention are essential requirements for implantable tissue-engineered products. Non-invasive imaging methods that can confirm location, retention, and biodistribution of transplanted cells attached to implanted tissue engineering scaffolds will be invaluable for the optimization and enhancement of regenerative therapies. To address this need, an injectable tissue engineering scaffold consisting of highly porous microspheres compatible with transplantation of cells is modified to contain the computed tomography (CT) contrast agent barium sulphate (BaSO4). The trackable microspheres show high x-ray absorption, with contrast permitting whole-body tracking. The microspheres are cellularized with GFP+ Luciferase+ mesenchymal stem cells and show in vitro biocompatibility. In vivo, cellularized BaSO4-loaded microspheres are delivered into the hindlimb of mice where they remain viable for 14 days. Co-registration of 3D-bioluminescent imaging and µCT reconstructions enable the assessment of scaffold material and cell co-localization. The trackable microspheres are also compatible with minimally-invasive delivery by ultrasound-guided transthoracic intramyocardial injections in rats. These findings suggest that BaSO4-loaded microspheres can be used as a novel tool for optimizing delivery techniques and tracking persistence and distribution of implanted scaffold materials. Additionally, the microspheres can be cellularized and have the potential to be developed into an injectable tissue-engineered combination product for cardiac regeneration.

Hard, Soft, and Hard-and-Soft Drug Delivery Carriers Based on CaCO3 and Alginate Biomaterials: Synthesis, Properties, Pharmaceutical Applications

Because free therapeutic drug molecules often have adverse effects on normal tissues, deliver scanty drug concentrations and exhibit a potentially low efficacy at pathological sites, various drug carriers have been developed for preclinical and clinical trials. Their physicochemical and toxicological properties are the subject of extensive research. Inorganic calcium carbonate particles are promising candidates as drug delivery carriers owning to their hardness, porous internal structure, high surface area, distinctive pH-sensitivity, low degradability, etc, while soft organic alginate hydrogels are also widely used because of their special advantages such as a high hydration, bio-adhesiveness, and non-antigenicity. Here, we review these two distinct substances as well as hybrid structures encompassing both types of carriers. Methods of their synthesis, fundamental properties and mechanisms of formation, and their respective applications are described. Furthermore, we summarize and compare similarities versus differences taking into account unique advantages and disadvantages of these drug delivery carriers. Moreover, rational combination of both carrier types due to their performance complementarity (yin-&yang properties: in general, yin is referred to for definiteness as hard, and yang is broadly taken as soft) is proposed to be used in the so-called hybrid carriers endowing them with even more advanced properties envisioned to be attractive for designing new drug delivery systems.