Gd-doped iron oxide nanoparticles were developed for use in tumour therapy via magnetic fluid hyperthermia (MFH). The nanoparticle composition was Gd_0.02Fe_2.98O₄ as determined by ICP-AES. TEM image analysis showed the primary particles to be about 13 nm in diameter. The specific power adsorption rate (SAR) determined with a field strength of 246 Oe and 52 kHz was 36 W per gram of Fe. This value is about 4 times higher than the reported SAR values for Fe₃O₄. The heating rate for the nanoparticles in vivo and the potential for tumour therapy were determined in a mouse model. The mouse models treated with doped iron oxide displayed much slower tumour growth, the tumour doubled its mass after 7 days post-treatment compared to 4 days for those models treated with standard iron oxide or saline solution.

Nanoparticle labels were used to detect the pathogenic bacteria Staphylococcus aureus. Two different labels were employed. These consisted of nanoparticles based on iron-oxide for magnetic trapping and isolation of the bacteria and surface enhanced Raman spectroscopy (SERS) active gold nanoparticles (AuNPs) coated with 4-mercaptobenzoic acid for the detection and quantification of the bacteria. Both types of nanoparticles were conjugated with single domain antibodies that selectively bind to protein A on the surface of S. aureus. Transmission electron microscopy (TEM) image analysis showed the iron-oxide nanoparticles to have magnetic core diameters of 20 nm ± 3 nm and the gold nanoparticles to be 51 nm ± 2 nm in diameter. A response curve was obtained displaying a logarithmic dependency between the 1073 cm⁻¹ peak intensity in the SERS spectra of the AuNPs and the concentration of S. aureus cells in the initial sample. The overall detection limit was estimated to be 1 S. aureus cell mL⁻¹ in less than 10 min without culturing.

The gadolinium-doped iron oxide nanoparticles (GdIONP) with greater specific power adsorption rate (SAR) than Fe₃O₄ was developed and its potential application in tumour therapy and particle tracking were demonstrated in transgenic adenocarcinoma of the mouse prostate C1 (TRAMP-C1) tumours. The GdIONPs accumulated in tumour region during the treatment could be clearly tracked and quantified by T2-weighted MR imaging. The therapeutic effects of GdIONP-mediated hyperthermia alone or in combination with radiotherapy (RT) were also evaluated. A significant increase in the tumour growth time was observed following the treatment of thermotherapy (TT) only group (2.5 days), radiation therapy only group (4.5 days), and the combined radio-thermotherapy group (10 days). Immunohistochemical staining revealed a reduced hypoxia region with vascular disruption and extensive tumour necrosis following the combined radio-thermotherapy. These results indicate that GdIONP-mediated hyperthermia can improve the efficacy of RT by its dual functions in high temperature (temperature greater than 45 °C)-mediated thermal ablation and mild-temperature hyperthermia (MTH) (temperature between 39 and 42 °C)-mediated reoxygenation.

The biological permeability and water solubility of drugs can pose substantial obstacles to oral drug delivery, the most common mode of drug administration for improving human health. Solubility determines the amount of drug that can be dissolved in solution, whereas permeability is the ability to permeate across biological membranes, determining therapeutic efficacy and safety. Some biological barriers, such as gastrointestinal pH, enzymes, and mucus, may affect the dissolution or absorption of therapeutic drugs. Physical or chemical approaches can be used to modify the water solubility or enhance the permeability. Moreover, nanocarriers, which can increase drug stability through encapsulation, enhance absorption due to their extensive surface area, and facilitate the targeted administration of medications to certain areas, could be useful for drug delivery systems. Nanoparticles can increase drug solubility by particle size reduction, complexation, and drug encapsulation and increase permeation by retention in tumors, opening of tight junctions, membrane fluidization, or intestinal mucoadhesion. Despite the many advantages of nanoparticle drug formulations, they also have several limitations, such as complicated manufacturing processes, nanotoxicity, and stability issues. In this article, we provide a comprehensive description of nanoparticle tools for maximizing oral drug delivery.