A thermo/pH/magnetic-responsive nanogel based on sodium alginate by modifying magnetic graphene oxide: Preparation, characterization, and drug delivery

Polycaprolactone/sodium alginate coaxial wet-spun fibers modified with carbon nanofibers and ceftazidime for improved clotting and infection control in wounds

Chronic wounds (CWs) are a significant public health concern and affect 1-2% of the world's population. They are responsible for high morbidity and mortality rates. Bacterial infections caused by Staphylococcus aureus and Pseudomonas aeruginosa are very common in CWs and prevent normal wound healing steps from taking place. Carbon nanofibers (CNFs) have attracted interest due to their inherent antibacterial and blood clotting abilities, as well as mechanical strength. The aim of this research was to engineer coaxial fibers by wet-spinning as new platforms for drug delivery in CW care (promoting rapid blood clotting and consequent tissue regeneration). Coaxial fibers were produced with an outer layer (shell) made of a mechanically resilient polycaprolactone (PCL at 10 wt%) reinforced with carbon nanofibers (CNFs at 50, 100, and 150 μg mL-1), while the inner layer (core) was made of a highly hydrated mixture of 2 wt% sodium alginate (SA) loaded with ceftazidime (CZ) at 128 μg mL-1 (minimum bactericidal concentration). The fibers' double-layer structure was verified by scanning electron microscopy. Core-shell fibers were deemed highly flexible and mechanically resilient and resistant to rupture, with such properties being improved with the incorporation of CNFs. Most fibers preserved their structural integrity after 28 days of incubation in physiological-like medium. Furthermore, data reported the ability of CZ combined with CNFs to fight microbial proliferation and showed that the presence of CNFs promoted blood clotting, with PCL/CNFs50 being the most effective from the group. It was found that higher concentrations of CNFs had a detrimental effect, highlighting a concentration-dependent response. The presence of PLC in the fibers resulted in a mitigation of the CNFs' cytotoxic impact on keratinocytes. The incorporation of CZ had no effect on the metabolic activity of the cells. Overall, the results demonstrated the potentialities of the engineered coaxial fibers for applications in wound care.

Sustainable and Surfactant-Free Synthesis of Negatively Charged Acrylamide Nanogels for Biomedical Applications

Nanogels offer unique advantages, like high surface-to-volume ratio, scalable synthetic methods, and easily tailored formulations, that allow us to control size and introduce stimuli-responsive properties. Their potential for drug delivery is significant due to their biocompatibility, high drug loading capacity, and controlled and sustained drug release. The development of greener and sustainable processes is essential for large-scale applications. We report the synthesis in water of covalently cross-linked acrylamide-based nanogels, both neutral and negatively charged, with varying amounts of acryloyl-l-proline, using high-dilution radical polymerization, without the need for surfactants. The use of a water-based synthesis resulted in nanogels with high monomer conversions and chemical yields, as well as lower polydispersity and smaller particle sizes for the negatively charged nanogels, leading to a more efficient synthetic methodology, with reduced loss of starting materials, higher potential for scalability, and reduction in costs. The suitability of these nanogels for biomedical applications was supported by cytotoxicity studies showing no significant reduction in viability on a human neuroblastoma cell line.

Smart Stimuli-responsive Alginate Nanogels for Drug Delivery Systems and Cancer Therapy: A Review

Nanogels are three-dimensional networks at the nanoscale level that can be fabricated through physical or chemical processes using polymers. These nanoparticles' biocompatibility, notable stability, efficacious drug-loading capacity, and ligand-binding proficiency make them highly suitable for employment as drug-delivery vehicles. In addition, they exhibit the ability to react to both endogenous and exogenous stimuli, which may include factors such as temperature, illumination, pH levels, and a diverse range of other factors. This facilitates the consistent administration of the drug to the intended site. Alginate biopolymers have been utilized to encapsulate anticancer drugs due to their biocompatible nature, hydrophilic properties, and cost-effectiveness. The efficacy of alginate nano gel-based systems in cancer treatment has been demonstrated through multiple studies that endorse their progress toward clinical implementation. This paper comprehensively reviews alginate and its associated systems in drug delivery systems.

Strategic Design of Intelligent-Responsive Nanogel Carriers for Cancer Therapy

Owing to the distinctive constituents of tumor tissue from those healthy organs, nanomedicine strategies show significant potentials in smart drug delivery. Nowadays, stimuli-responsive nanogels are playing increasingly important roles in the application of cancer therapy because of their sensitivity to various internal or external physicochemical stimuli, which exhibit site-specific and markedly enhanced drug release. Besides, nanogels are promising as drug carriers because of their porous structures, good biocompatibility, large surface area, and excellent capability with drugs. Taking advantage of multiresponsiveness, recent years have witnessed the rapid evolution of stimulus-responsive nanogels from monoresponsive to multiresponsive systems; however, there lacks a comprehensive review summarizing these reports. In this Review, we discuss the properties, synthesis, and characterization of nanogels. Moreover, tumor microenvironment and corresponding designing strategies for stimuli-response nanogels, both exogenous (temperature, magnetic field, light) and endogenous (pH, biomolecular, redox, ROS, pressure, hypoxia) are summarized on the basis of the recent advances in multistimuli-responsive nanogel systems. Nanogel and two-dimensional material composites show excellent performance in the field of constructing multistimulus-responsive nanoparticles and precise intelligent drug release integrated system for multimodal cancer diagnosis and therapy. Finally, potential progresses and suggestions are provided for the further design of hybrid nanogels based on emerging two-dimensional materials.

Target-Specific Superparamagnetic Hydrogel with Excellent pH Sensitivity and Reversibility: A Promising Platform for Biomedical Applications

Superparamagnetism has been widely used for many biomedical applications, such as early detection of inflammatory cancer and diabetes, magnetic resonance imaging (MRI), hyperthermia, etc., whereas incorporation of superparamagnetism in stimulus-responsive hydrogels has now gained substantial interest and attention for application in these fields. Recently, pH-responsive superparamagnetic hydrogels showing the potential use in disease diagnosis, biosensors, polymeric drug carriers, and implantable devices, have been developed based on the fact that pH is an important environmental factor in the body and some disease states manifest themselves by a change in the pH value. However, improvement in pH sensitivity of magnetic hydrogels is a dire need for their practical applications. In this study, we report the distinctly high pH sensitivity of new synthesized dual-responsive magnetic hydrogel nanocomposites, which was accomplished by copolymerization (free-radical polymerization) of two pH-sensitive monomers, acrylic acid (AA) and vinylsulfonic acid (VSA) with an optimum ratio, in the presence of presynthesized superparamagnetic iron oxide nanoparticles (Fe3O4(OH) x ). The monomers contain pH-sensitive functional groups (COO- and SO3 - for AA and VSA, respectively), and they have also been widely used as biomaterials because of the good biocompatibility. The pH sensitivity of the superparamagnetic hydrogel, poly(acrylic acid-co-vinylsulfonic acid), PAAVSA/Fe3O4, was investigated by swelling studies at different pH values from pH 7 to 1.4. Distinct pH reversibility of the system was also demonstrated through swelling/deswelling analysis. Thermal stability, chemical configuration, magnetic response, and structural properties of the system have been explored by suitable characterization techniques. Furthermore, the study reveals a pH-responsive significant change in the overall morphology and packing fraction of iron oxide nanoparticles in PAAVSA/Fe3O4 via energy-dispersive X-ray (EDX) elemental mapping with the field emission scanning electron microscopy (FESEM) study (for freeze-dried PAAVSA/Fe3O4, swelled at different pH values), implying a drastic change in susceptibility and induced saturation magnetization of the system. These important features could be easily utilized for the purpose of diagnosis using magnetic probe and/or impedance analysis techniques.

Molecular Dynamics Simulation, Characterization and In Vitro Drug Release of Isoniazid Loaded Poly-ε-caprolactone Magnetite Nanocomposite

Background: This study reports on the development of a controlled-release isoniazid (INH) drug delivery system using poly-є-caprolactone (PCL) functionalized magnetite-nanoparticles (MNPs), as a theoretical potential tool for tuberculosis (TB) chemotherapy. Method: The magnetite Fe3O4 core was fabricated by the co-precipitation method and coated with PCL by emulsion polymerization. INH was loaded onto the PCL-MNP surface to shape an INH-PCL-MNP nanocomposite. Deposing the INH on the nanocomposite surface was demonstrated through the molecular dynamics simulations. To investigate the stability of the polymer, the root-mean-square deviation (RMSD) and the radius of gyration (Rg) were calculated. The composite was characterized by Scanning electron microscopy (SEM) and X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Mycobacterium tuberculosis was used to assess the antimicrobial activity of the nanoparticles. The drug loading efficiency, drug content, and in-vitro release behavior of the INH-PCL-MNPs were evaluated by UV–Vis spectrophotometry. Results: RMSD of PCL show that the structure of polymer after 40 ns is stable. INH molecules interested to spend more time close to the polymer. Rg of PCL indicated that PCL folded and radius of gyration changed near 1nm. The drug loading efficiency and drug content of the NPs were 720±46 mg/g and 69.3±3.8 (%), respectively. The compound showed a strong level of activity in-vitro. The amount of drug release at all times was above the minimum inhibitory concentration (MIC) (6 μg/ml). Conclusion: INH-PCL-MNP nanocomposite have been effectively used as a potential tool to treat TB infections and a magnetic drug carrier system.

Folate-modified Graphene Oxide as the Drug Delivery System to Load Temozolomide

OBJECTIVE

The folate-modified graphene oxide (GO-FA), which had good stability and biocompatibility on rat glioma cells was successfully prepared.

METHODS

The formation and composition of GO-FA were confirmed by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectrum (FT-IR), Raman spectra and X-ray Photoelectron Spectroscopy (XPS spectra). The cell experiment suggested good biocompatibility of GO-FA on rat glioma cells.

RESULTS

The experiment of GO-FA loading with Temozolomide (TMZ) showed that the maximum drug loading of GO-FA was 8.05 ± 0.20 mg/mg, with the drug loading rate of 89.52 ± 0.19 %. When TMZ was released from the folate-modified graphene oxide loading with temozolomide (GO-FATMZ), its release behavior in vitro showed strong pH dependence and sustained release property. The growth of rat glioma cells can be effectively inhibited by GO-FA-TMZ, with the cell inhibition rate as high as 91.72 ± 0.13 % at the concentration of 600 μg/mL and time of 72 h.

CONCLUSION

According to the above experimental results, this composite carrier has potential applications in drug delivery and cancer therapy.