Biocompatibility of core@shell particles: Cytotoxicity and genotoxicity in human osteosarcoma cells of colloidal silica spheres coated with crystalline or amorphous zirconia

Advanced nanoscale drug delivery systems for bone cancer therapy

Bone tumors are relatively rare, which are complex cancers and mostly involve the long bones and pelvis. Bone cancer is mainly categorized into osteosarcoma (OS), chondrosarcoma, and Ewing sarcoma. Of these, OS is the most intimidating cancer of the bone tissue, which is mostly found in the log bones in young children and older adults. Conspicuously, the current chemotherapy modalities used for the treatment of OS often fail mainly due to (i) the non-specific detrimental effects on normal healthy cells/tissues, (ii) the possible emergence of drug resistance mechanisms by cancer cells, and (iii) difficulty in the efficient delivery of anticancer drugs to the target cells. To impose the maximal therapeutic impacts on cancerous cells, it is of paramount necessity to specifically deliver chemotherapeutic agents to the tumor site and target the diseased cells using advanced nanoscale multifunctional drug delivery systems (DDSs) developed using organic and inorganic nanosystems. In this review, we provide deep insights into the development of various DDSs applied in targeting and eradicating OS. We elaborate on different DDSs developed using biomaterials, including chitosan, collagen, poly(lactic acid), poly(lactic-co-glycolic acid), polycaprolactone, poly(ethylene glycol), polyvinyl alcohol, polyethyleneimine, quantum dots, polypeptide, lipid NPs, and exosomes. We also discuss DDSs established using inorganic nanoscale materials such as magnetic NPs, gold, zinc, titanium NPs, ceramic materials, silica, silver NPs, and platinum NPs. We further highlight anticancer drugs' role in bone cancer therapy and the biocompatibility of nanocarriers for OS treatment.

Bioinspired Heteromultivalent Chitosan-α-Fe₂O₃/Gadofullerene Hybrid Composite for Enhanced Antibiotic-Resistant Bacterial Pneumonia

Herein, we have designed and developed a heteromultivalent chitosan base α-Fe₂O₃/Gadofullerene (GdF) hybrid composite through a simple chemical precipitation method. Unlike other methods, the addition of external stabilizing agents to generate GdF nanoparticles (NPs) was not necessary herein. The prepared chitosan-α-Fe₂O₃/GdF hybrid nanocomposites were characterized using UV, FT-IR, XRD and morphological microscopic analyses. The results showed that α-Fe₂O₃ and GdF hybrid nanocomposites were successfully grown on the surface of chitosan. The FT-IR vibration peaks showed the formation of Fe₂O₃ NPs, and the vibration peak for Fe-O was 568 cm^-1. The broad absorption peak observed in the range of 250-350 nm and a sharp absorption peak at 219 nm represents the UV absorption of the synthesized hybrid composites. XRD pattern showed sharp peaks of crystallinity and purity of α-Fe₂O₃ nanoparticles. Finally, the synthesized chitosan-α-Fe₂O₃/GdF hybrid composites were screened for their antibacterial resistance against the Escherichia coli, Pseudomonas aeruginosa, Bacilus subtilis, and Staphylococcus aereus. In addition, in vitro biocompatibility results exhibited that developed hybrid samples have provided high cell compatibility with fibroblast (L929) cell line. The in vivo bio inspired nanotherapeutics have the potential action to effective inhibition ability on antibiotic-resistant P. aeruginosa, which has been main factor of inducing pneumonia. In conclusion, we expect biomimicking systems combined with the effective antibacterial agent could be the suitable next generation therapeutic potential factors for prevention and treatment of antibiotic-resistant pneumonia.

Mesoporous silica nanoparticles prepared by different methods for biomedical applications: Comparative study

In the current investigation, mesoporous silica nanoparticles were obtained by various techniques, namely sol-gel (S1), micro-emulsion (S2) and hydrothermal synthesis (S3). The effect of those methods on the final features of the obtained mesoporous silica nanoparticles was studied. The obtained nanoparticles were investigated by TEM, BET surface area, Zetasizer, XRD and FTIR. The preparation method effect was evaluated on the drug release behaviour using doxycycline hyclate as a model drug. In addition, the degree of their compatibility against Saos-2 cell line was also determined. The morphology and microstructure of silica nanoparticles were found to be dependent on the utilised method. Those techniques produced particles with particle sizes of 50, 30-20 and 15 nm and also surface areas of 111.04, 164 and 538.72 m2 /g, respectively, for S1, S2 and S3. However, different preparation methods showed no remarkable changes for the physical and chemical integrities. The drug release test showed faster release from S2 compared with S1 and S3, which make them more applicable in cases require large doses for short periods. However, the release behaviour of S3 was satisfied for treatments which require long period with relatively highest release rate. The preparation method influenced the cell viability as S1 and S2 showed acceptable cell cytotoxicity compared with S3.

Bacterial adhesion on amorphous and crystalline metal oxide coatings

Several studies have demonstrated the influence of surface properties (surface energy, composition and topography) of biocompatible materials on the adhesion of cells/bacteria on solid substrates; however, few have provided information about the effect of the atomic arrangement or crystallinity. Using magnetron sputtering deposition, we produced amorphous and crystalline TiO2 and ZrO2 coatings with controlled micro and nanoscale morphology. The effect of the structure on the physical-chemical surface properties was carefully analyzed. Then, we studied how these parameters affect the adhesion of Escherichia coli and Staphylococcus aureus. Our findings demonstrated that the nano-topography and the surface energy were significantly influenced by the coating structure. Bacterial adhesion at micro-rough (2.6 μm) surfaces was independent of the surface composition and structure, contrary to the observation in sub-micron (0.5 μm) rough surfaces, where the crystalline oxides (TiO2>ZrO2) surfaces exhibited higher numbers of attached bacteria. Particularly, crystalline TiO2, which presented a predominant acidic nature, was more attractive for the adhesion of the negatively charged bacteria. The information provided by this study, where surface modifications are introduced by means of the deposition of amorphous or crystalline oxide coatings, offers a route for the rational design of implant surfaces to control or inhibit bacterial adhesion.