Hydroxyapatite (HAp)/reduced graphene oxide (rGO)/yttrium oxide (Y2O3) composites were prepared by ethanol-assisted wet blending (colloidal dispersion), followed by drying and heat treatment, and systematically characterized. This study investigates the structural, optical, and functional enhancement in hydroxyapatite (HAp) after the incorporation of reduced graphene oxide (rGO) and yttrium oxide (Y2O3), aiming to develop multifunctional bioceramics for dual applications in bone regeneration. HAp/rGO/Y2O3 composites were prepared by ethanol-assisted wet blending (colloidal dispersion), followed by drying and heat treatment, and systematically characterized. XRD analysis confirmed the phase purity of the composites and revealed reduced crystallite sizes upon doping, while FT-IR spectroscopy validated the presence of functional groups linked with phosphate, hydroxyl, and rGO/Y2O3 interactions. SEM investigation displayed dense, homogeneous morphologies with reduced particle sizes (∼380 nm), which are favorable for biomedical integration. UV/visible spectroscopy showed a significant narrowing of the optical bandgap from 5.42 eV in pure HAp to 4.73 eV in HAp/rGO/Y2O3 composites. This bandgap reduction was attributed to the π-conjugation of rGO and defect states introduced by Y2O3, thereby enhancing light absorption and rendering the composites promising candidates for photothermal and oxidative cancer therapies. The combined effect of rGO's electron transport and Y2O3's reactive oxygen species (ROS) generation potential is expected to induce synergistic anticancer activity while preserving osteoconductivity. The tested AA3 formula demonstrated a promising level of biofilm reduction rates against Gram-positive bacteria, e.g. Streptococcus pneumoniae (97.27% ± 5.36%), Staphylococcus epidermidis (95.89% ± 2.85%), Staphylococcus aureus (94.77% ± 1.24%), and Bacillus cereus (92.90% ± 0.95%). Additionally, its minimum inhibitory dosage (MIC) against Gram-positive bacteria ranged from 80 to 100 µg mL-1, with a bactericidal effect (MBC) at 120 µg mL-1. In vitro cytotoxicity studies on Vero cells demonstrated the safety of our tested materials and composites. The MTT assay showed that HAP, Y2O3, rGO and their different composites (AA1 and AA3-AA5) exhibited CC50 values above 100 µg mL-1. By contrast, the CC50 value of the AA2 composite was detected at 8.5 µg L-1. Consequently, our composites have the potential to be used in biomedical applications. Overall, our results suggest that HAp/rGO/Y2O3 nanocomposites exhibit improved physicochemical and optical properties and hold substantial promise as dual-functional materials for integrated bone healing and localized cancer treatment platforms.

Hydroxyapatite (HAp)/reduced graphene oxide (rGO)/yttrium oxide (Y 2 O 3 ) composites were prepared by ethanol-assisted wet blending (colloidal dispersion), followed by drying and heat treatment, and systematically characterized.

This work reports the successful fabrication of PLA/PS–BaTiO3 nanocomposite films with significantly enhanced UV protection capabilities. BaTiO3 nanoparticles (2–8 wt%) were incorporated into a PLA/PS matrix via solution casting, and their influence on optical and dielectric properties was systematically evaluated. XRD analysis confirmed the formation of BaTiO3 with an estimated crystallite size of ∼57 nm according to the Scherrer equation, indicating a well-defined nanoscale structure. UV–Vis spectroscopy revealed a pronounced increase in UV absorption intensity accompanied by a clear red-shift in the absorption edge with rising BaTiO3 content. This strong UV attenuation is attributed to charge-transfer interactions between BaTiO3 and polymer functional groups, which introduce additional defect states that facilitate photon trapping. The reduction of the direct optical band gap from 3.84 eV to 3.23 eV and the indirect band gap from 3.39 eV to 2.78 eV at 8 wt% BaTiO3 loading, highlighting the extent of enhancement in UV attenuation. Complementary FT-IR, XRD, and SEM analyses confirmed structural compatibility and uniform nanofiller dispersion, which contribute to improved interfacial polarization and charge transport. Dielectric and electric modulus studies verified non-Debye relaxation behavior and enhanced ion mobility, supporting the superior energy dissipation capability of the nanocomposites under UV exposure. Overall, the combined optical and electrical features establish PLA/PS–BaTiO3 nanocomposites as highly promising materials for UV-shielding films, protective coatings, and optoelectronic packaging applications.

Microbubbles (MBs) are gaining increased interest in biomedical applications. They are typically in the range of 1–10 μm, composed of a shell made of polymers, lipids, proteins, or surfactant, encapsulating heavy gas such as; sulfur hexafluoride (SF6), or perfluorocarbons. MBs have a range of medical applications, from ultrasound image enhancement, to drug delivery, and gas delivery. In this study, Chitosan-coated MBs is produced by reacting chitosan and glycerol to produce a shell of crosslinked polymer with SF6 as the gas core. The population was tested for the presence of Nanobubbles. Moreover, freeze drying has been used to test the capability of the new shell to withstand the freeze-drying conditions. The main point of freeze drying is to allow long term storage of bubbles, facilitate bubble transportation, and change the gas core to oxygen to enhance the benefits of using these MBs. Different characterization techniques have been used, FTIR to confirm that we have developed the hypothesized CS shell for micro/nanobubbles. TEM to test the and image the presence of nanobubbles. The results showed that the produced population included microbubbles and nanobubbles with mean diameter of 3.57 ± 0.71 μm and 55 ± 37 nm respectively. The bubbles have a surface positive charge and high concentration of 1.02 × 1012 MBs/ml. Moreover, freeze-drying was used to change the gas core to oxygen producing MBs with mean diameter 1 ± 0.7 μm and concentration of 6.5 × 109 MBs/ml. These results indicate the potential of using this new formulation for production of bubbles that can be used for various applications. Further investigation is still in progress for extra optimization and application.

Polymer nanocomposites (PNC) based on polymethyl methacrylate (PMMA) and polyvinylidene fluoride (PVDF) were synthesized by the casting technique, incorporating different weight percentages of multi-walled carbon nanotubes and Bismuth oxide nanoparticles (MCTBO NP). The prepared films were subjected to 100 kGy of gamma irradiation to investigate structural and functional modifications. X-ray diffraction (XRD) analysis revealed that doping with MCTBO led to a notable increase in the amorphous phase and a corresponding decrease in crystallinity. This structural transition was further supported by an increase in Urbach energy from 0.175 eV to 3.25 eV, particularly after irradiation, indicating enhanced structural disorder. Scanning electron microscopy (SEM) confirmed the uniform dispersion of nanoparticles throughout the polymer matrix, verifying successful integration of nanofillers. Optical characterization demonstrated a significant reduction in the optical band gap (indirect), which decreased from 3.87 eV to 3.18 eV upon MCTBO doping, and further to 2.36 eV after irradiation. This reduction is attributed to increased cross-linking and the introduction of localized states resulting from radiation exposure. Tauc’s plots indicated that the optical transitions in both irradiated and non-irradiated samples are of the indirect type. Moreover, the Urbach energy increased with both higher MCTBO content and gamma irradiation, reflecting greater electronic disorder. Additionally, electrical conductivity and dielectric properties were evaluated before and after irradiation. Results demonstrated enhanced dielectric constant and electrical conductivity with increasing MCTBO concentration and post-irradiation, suggesting improved charge transport characteristics. Among all samples, the PMMA/PVDF nanocomposite containing 6 wt% MCTBO exhibited the most superior performance, surpassing both the pristine blend and its non-irradiated counterpart. The enhanced structural, optical, and electrical properties highlight the potential of these irradiated nanocomposites for advanced applications in optoelectronic devices, energy storage systems, and radiation shielding materials.

This work reports two different strategies for the formation of hybrid microbeads using chitosan and polyethylene glycol (PEG) as based biodegradable materials for radiation shielding. An organic–inorganic hydrogel was prepared by ionotropic gelation. During the in-situ loading, incorporating magnetic nanoparticles Fe2O3 into the polymer matrix, magnetic nanostructures, were entrapped in the polymer matrix during the physical cross-linking of the polymer with the physical cross-linker (sodium triphosphate). However, in case of post-loading mechanism the loaded nanoparticles favor the precipitation on the surface of the formed beads. We use different characterization techniques for our systems such as scanning electron microscopy (SEM), x-ray, infrared spectroscopy (XRD), and X-ray radiation shielding application. The results demonstrate that by incorporating nanostructured magnetic particles into the polymer matrix, the surface morphology based on the two processes allow the magnetic nanoparticles to be embedded or form an outer shell and precipitated on the surface of polymer microbeads. The values of μ for the hydrogels loaded with Fe2O3 by in-situ process have the larger values of the linear coefficient however, in case of post-loading process the values dramatically decrease in compare with the in-situ ones at the same tube voltage. The presented work recommended as a good mentor for radiation shielding.

Microbubbles (MBs) are gaining increased interest in biomedical applications. MBs size typically range from 0.1 to 10 µm and formed with different shells such as (lipid, polymer, protein, and surfactant). The shell encapsulates a gaseous core containing gases such as oxygen, sulfur hexafluoride SF6, or perfluorocarbons. MBs have a range of medical applications, such as medical imaging, drug delivery, and gas delivery. Freeze-drying of MBs have been used by different groups to help reconstitute them at the point of care. This would become advantageous for better control of the encapsulated drug and gas, MB concentration, and protocols of administration and would also allow off-site production at lower cost. In this study, we developed a protocol to use chitosan and glycerol to produce Chitosan-coated MBs with SF6 as the gas core at high concentration and stability. Moreover, freeze drying has been used to change the gas core to oxygen to enhance the benefits of using these MBs. The idea is to be able to produce oxygen MBs with better stability to enhance the chemotherapy and radiotherapy effect on cancerous cells by relieving hypoxia and increasing the cell sensitivity. We used different characterization techniques for our systems to demonstrate that we have developed a novel CS shell for micro/nanobubbles as shell with SF6 as core at low cost. We obtained not only MBs with mean diameter 3.57 ± 0.71µm but also nanobubbles with 55 ± 37nm diameter with a surface positive charge and high concentration of 1.02x1012 MBs/ml. Moreover, freeze-drying was used to change the gas core to oxygen producing MBs with mean diameter 1 ± 0.7 µm and concentration of 6.5 × 108 MBs/ml.

AbstractA strategy for the preparation of a hybrid chitosan/silica nanohydrogel is reported, which combines the gelation of chitosan in a nanoemulsion system with a sol–gel process to produce silica. Chitosan is used as a biopolymer matrix, while silica acts as a structuring additive. Hydrogel nanocapsules are obtained through the ionic interaction of the cationic groups of chitosan with the anionic groups of sodium triphosphate (STP), which is used as a physical cross‐linker. Two alternative preparation methods are compared in this work: in the first one, STP is added to the continuous phase of an inverse emulsion of chitosan; in the second one, the fusion of droplets of two emulsions containing separate chitosan and STP takes place. The size of the obtained nanocapsules ranges from 50 to 200 nm. The efficiency of the formed hydrogel for entrapping a hydrophilic model substance (erioglaucine disodium salt) is investigated for the two systems by studying the release in a neutral aqueous medium. The results indicate that the hydrophilic cargo is efficiently encapsulated by both preparation methods, although the droplet‐fusion method yields more stable suspensions. As a general observation, the release behavior of erioglaucine is systematically retarded when silica is present in the systems.

Nanocomposite blend films were prepared by a simple casting method. Polyvinyl propylene (PVP) and chitosan (PVP/chitosan) were used as a based material. Different CuO nanoparticles concentrations were added to a specific blend film concentration of PVP/chitosan (80/20). The mechanism of the interaction between the blend and the nanoparticles was studied by different characterization techniques. The structure modification was confirmed by X-ray diffraction pattern due to the addition of the nanoparticles, in addition, the complexation and the miscibility between the nanoparticles and the blended composite was confirmed by UV–Vis spectroscopy and Fourier transform infrared spectroscopy is by the appearance of new peaks in the spectrum. The band gap computation and optical characteristics show that the addition of the nanoparticles decreases the crystallinity of the nanocomposites system. The findings show that the surface morphology checked by scanning electron microscopy shape and swelling rate behavior are affected by the integration of CuO nanoparticles into the polymer blend matrix. From all the results, this work has a great interest in wide bioapplications such as wound healing and food packing.

The present study is aimed to examine the structural, optical, thermal and mechanical properties of multi-walled carbon nanotubes-Polycaprolactone /Poly methyl methacrylate (MWCNTs-PCL/PMMA) nanocomposites samples by using various techniques. Nanocomposites samples (MWCNT-PCL/PMMA) were prepared by using the casting technique. The interaction of PCL/PMMA blend with MWCNTs has been assessed by using XRD and UV–Vis spectroscopy. From the XRD data, the addition of MWCNTs to the PCL/PMMA blend has been enhancing the amorphous nature of the blend. Using UV–Vis. measurements, the changes in absorbance, extinction coefficient, refractive index, and energy gap parameters were determined showing enhancement for various applications. The optical energy band gap of the MWCNT-PCL/PMMA films was decreased with the increase of the nanofiller content. The morphology shown by the SEM has guaranteed the uniform dispersion of MWCNTs in the blend. The disordered organization of MWCNTs in the blend is revealed by the glass transition temperature of the composite, which has been observed to decrease with an increase in MWCNTs content. TGA has demonstrated the nanocomposites samples superior thermal stability compared to a pure PCL/PMMA blend and its enhancement with the addition of MWCNTs. The loading of MWCNTs has shown an increasing trend in the mechanical properties of the nanocomposites samples, such as tensile strength and young’s modulus. The MWCNTs-PCL/PMMA films offer special qualities that enable them to be used in for different applications.

Polysaccharide/silica hybrid microcapsules were prepared using ionic gelation followed by spray-drying. Chitosan and alginate were used as biopolymer matrices, and in situ prepared silica was used as a structuring additive. The prepared microparticles were used in two very different applications: the encapsulation of hydrophilic molecules, and as a support for palladium nanoparticles used as catalysts for a model organic reaction, namely the reduction of p-nitrophenol by sodium borhydride. In the first application, erioglaucine disodium salt, taken as a model hydrophilic substance, was encapsulated in situ during the preparation of the microparticles. The results indicate that the presence of silica nanostructures, integrated within the polymer matrix, affect the morphology and the stability of the particles, retarding the release of the encapsulated substance. In the second application, chloropalladate was complexed on the surface of chitosan microparticles, and palladium(II) was subsequently reduced to palladium(0) to obtain heterogeneous catalysts with an excellent performance.

A PCL/PMMA blend system with low contents of multi-walled carbon nanotubes was prepared using a high prop sonicator with casting techniques. The X-ray analysis revealed that adding MWCNTs to the polymer blend did not affect crystallinity but had little effect on d space. Some changes in the positions of IR bands were observed due to the interaction between MWCNTs and the polymer blend. SEM images revealed that the grain size formed and became a definite shape after adding MWCNTs. Mechanical analysis shows that incorporating MWCNTs in the polymeric matrices improves the mechanical properties of both tensile stress and elastic modulus Differential scanning calorimetry indicates that adding MWCNTs enhances the thermal stability of the prepared nanocomposites. The thermogravimetric analysis (TGA) showed a significant weight loss from 357–440 °C for all the prepared samples.

We report the preparation of a hybrid chitosan/silica three-dimensional (3D) scaffold loaded simultaneously with two model hydrophilic substances, ibuprofen sodium salt and erioglaucine disodium salt. The first substance is entrapped in situ during the preparation of chitosan submillimetric beads by ionotropic gelation with sodium triphosphate, while the latter is post-loaded during the scaffold formation. Controlled release experiments carried out under neutral conditions demonstrate that the presence of nanostructured silica within the polymer matrix retards the release of both hydrophilic substances and increases the structure stability of the scaffold. Release profiles can be fitted to a two-component model with a diffusion-controlled term (Korsmeyer-Peppas model), which dominates the release of the post-loaded substance, and a second swelling/erosion term, which becomes relevant for the in situ entrapped drug.

Nanoemulsions are kinetically stabilized emulsions with droplet sizes in the nanometer scale. These nanodroplets are able to confine spaces in which reactions of polymerization or precipitation can take place, leading to the formation of particles and capsules that can act as nanocarriers for biomedical applications. This review discusses the different possibilities of using nanoemulsions for preparing biomedical nanocarriers. According to the chemical nature, nanocarriers prepared in nanoemulsions are classified in polymeric, inorganic, or hybrid. The main synthetic strategies for each type are revised, including miniemulsion polymerization, nanoemulsion-solvent evaporation, spontaneous emulsification, sol-gel processes, and combination of different techniques to form multicomponent materials.

This work reports an in situ strategy for the synthesis of hybrid sub-millispheres as carriers for encapsulating and controlling the release of hydrophilic pharmaceutical compounds in both neutral and acidic media. An organic-inorganic hydrogel is prepared by ionotropic gelation, and its efficiency for entrapping hydrophilic molecules is investigated. Two biopolymers, namely chitosan or alginate, are used to generate a scaffold network, in which the formation of silica nanoparticles takes place in situ by a sol-gel process. Model hydrophilic molecules (erioglaucine disodium salt and ephedrine hydrochloride) are encapsulated within polymer matrix, and the subsequent release is controlled by tailoring the hybrid network structure. Kinetic studies demonstrate that the release of the active substance is slower in the presence of silica, which increases as well the structural stability of the carrier in both neutral and acidic media. As a result, by incorporating nanostructured silica into the polymer matrix, the presented system overcomes the limitations of the ionotropic method for entrapping hydrophilic substances.

•Spectroscopic studies and thermal properties of PCL/PMMA biopolymer blend.