Influence of silica coating process on fine structure and magnetic properties of iron oxide nanoparticles

Smart and Multi-Functional Magnetic Nanoparticles for Cancer Treatment Applications: Clinical Challenges and Future Prospects

Iron oxide nanoparticle (IONPs) have become a subject of interest in various biomedical fields due to their magnetism and biocompatibility. They can be utilized as heat mediators in magnetic hyperthermia (MHT) or as contrast media in magnetic resonance imaging (MRI), and ultrasound (US). In addition, their high drug-loading capacity enabled them to be therapeutic agent transporters for malignancy treatment. Hence, smartening them allows for an intelligent controlled drug release (CDR) and targeted drug delivery (TDD). Smart magnetic nanoparticles (SMNPs) can overcome the impediments faced by classical chemo-treatment strategies, since they can be navigated and release drug via external or internal stimuli. Recently, they have been synchronized with other modalities, e.g., MRI, MHT, US, and for dual/multimodal theranostic applications in a single platform. Herein, we provide an overview of the attributes of MNPs for cancer theranostic application, fabrication procedures, surface coatings, targeting approaches, and recent advancement of SMNPs. Even though MNPs feature numerous privileges over chemotherapy agents, obstacles remain in clinical usage. This review in particular covers the clinical predicaments faced by SMNPs and future research scopes in the field of SMNPs for cancer theranostics.

Progress and prospects of magnetic iron oxide nanoparticles in biomedical applications: A review

Nanoscience has been considered as one of the most substantial research in modern science. The utilization of nanoparticle (NP) materials provides numerous advantages in biomedical applications due to their unique properties. Among various types of nanoparticles, the magnetic nanoparticles (MNPs) of iron oxide possess intrinsic features, which have been efficiently exploited for biomedical purposes including drug delivery, magnetic resonance imaging, Magnetic-activated cell sorting, nanobiosensors, hyperthermia, and tissue engineering and regenerative medicine. The size and shape of nanostructures are the main factors affecting the physicochemical features of superparamagnetic iron oxide nanoparticles, which play an important role in the improvement of MNP properties, and can be controlled by appropriate synthesis strategies. On the other hand, the proper modification and functionalization of the surface of iron oxide nanoparticles have significant effects on the improvement of physicochemical and mechanical features, biocompatibility, stability, and surface activity of MNPs. This review focuses on popular methods of fabrication, beneficial surface coatings with regard to the main required features for their biomedical use, as well as new applications.

Enhanced sensitivity and efficiency of detection of Staphylococcus aureus based on modified magnetic nanoparticles by photometric systems

Staphylococcus aureus is an important infectious factor in the food industry and hospital infections. Many methods are used for detecting bacteria but they are mostly time-consuming, poorly sensitive. In this study, a nano-biosensor based on iron nanoparticles (MNPs) was designed to detect S. aureus. MNPs were synthesized and conjugated to Biosensors. Then S. aureus was lysed and nano-biosensor (MNP-TiO₂-AP-SMCC-Biosensors) was added to the lysed bacteria. After bonding the bacterial genome to the nano-biosensor, MNPs were separated by a magnet. Bacterial DNA was released from the surface of nano-biosensor and researched by Nano-drop spectrophotometry. The results of SEM and DLS revealed that the size of MNPs was 20-25 nm which increased to 38-43 nm after modification and addition of biosensors. The designed nano-biosensor was highly sensitive and specific for the detection of S. aureus. The limit of detection (LOD) was determined as 230 CFU mL^-1. There was an acceptable linear correlation between bacterial concentration and absorption at 3.7 × 10²-3.7× 10⁷ whose linear diagram and regression was Y = 0.242X + 2.08 and R² = .996. Further, in the presence of other bacteria as a negative control, it was absolutely specific. The sensitivity of the designed nano-biosensor was investigated and compared through PCR.

Cloaking Silica Nanoparticles with Functional Protein Coatings for Reduced Complement Activation and Cellular Uptake

Silica-coated nanoparticles are widely used in biomedical applications such as theranostics, imaging, and drug delivery. While silica-coated nanoparticles are biocompatible, experimental evidence shows that they can trigger innate immune reactions, and a broader understanding of what types of reactions are caused and how to mitigate them is needed. Herein, we investigated how the noncovalent surface functionalization of silica nanoparticles with purified proteins can inhibit nanoparticle-induced complement activation and macrophage uptake, two of the most clinically relevant innate immune reactions related to nanomedicines. Silica nanoparticles were tested alone and after coating with bovine serum albumin, human serum albumin, fibrinogen, complement factor H (FH), or immunoglobulin G (IgG) proteins. Enzyme-linked immunosorbent assays measuring the generation of various complement activation products indicated that silica nanoparticles induce complement activation via the alternative pathway. All protein coatings other than IgG protected against complement activation to varying extents. Most proteins acted as steric blockers to inhibit complement protein deposition on the nanoparticle surface, while FH coatings were biologically active and inhibited a key step in the amplification loop of complement activation, as confirmed by Western blot analysis. Flow cytometry and fluorescence microscopy experiments further revealed that complement activation-inhibiting protein coatings blunted macrophage uptake as well. Taken together, our findings demonstrate a simple and effective way to coat silica nanoparticles with purified protein coatings in order to mitigate innate immune reactions. Such methods are readily scalable and might constitute a useful strategy for improving the immunological safety profile of silica and silica-coated nanoparticles as well as other types of inorganic nanoparticles.

Functionalization of anti-Brucella antibody based on SNP and MNP nanoparticles for visual and spectrophotometric detection of Brucella

An Immuno-Nano-Biosensor with high sensitivity was designed based on iron and silica nanoparticles to detect B. abortus. Briefly explain, primary polyclonal antibody (IgG₁) was conjugated on surface magnetic nanoparticles (MNPs) to form MNP-IgG₁. Secondary polyclonal antibody (IgG₂) and Horseradish Peroxidase enzyme were conjugated on silica nanoparticles (SNPs) to form HRP-SNP-IgG₂. HRP-SNP-IgG₂. MNP-IgG₁ and HRP-SNP-IgG₂ were added to B. abortus. The MNP-IgG₁-B.abortus-IgG₂-SNP-HRP complex was isolated from the reaction mixture using a magnet. After that, tetramethylbenzidine was added to the complex. The reaction was stopped with HCl and investigated using UV-Vis spectrophotometry. The nanoparticles' structure and size were investigated using SEM and DLS. Immuno-Nano-Biosensor sensitivity and specificity were determined. The SEM and DLS results indicated that the SNPs, MNPs, HRP-SNP-IgG₂ and MNP-IgG₁ size and structure were 35, 44, 60 and 56 nm, respectively. In addition, a good linear correlation was observed at 10²-10⁷ CFU mL^-1 concentrations, which their linear equation and regression were Y = 0.3× + 0.18 and R² 0.982, respectively. The limitation of detecting B. abortus was 160 CFU mL^-1. Finally, the results demonstrated that those designed Immuno-Nano-Biosensor could be specifically detected B. abortus and B. melitensis in real samples.