The current standard of diabetes management depends upon the invasive blood pricking techniques. In recent times, the availability of minimally invasive continuous glucose monitoring devices have made some improvements in the life of diabetic patients however it has its own limitations which include painful insertion, excessive cost, discomfort and an active risk due to the presence of a foreign body under the skin. Due to all these factors, the non-invasive glucose monitoring has remain a subject of research for the last two decades and multiple techniques of non-invasive glucose monitoring have been proposed. These proposed techniques have the potential to be evolved into a wearable device for non-invasive diabetes management. This paper reviews research advances and major challenges of such techniques or methods in recent years and broadly classifies them into four types based on their detection principles. These four methods are: optical spectroscopy, photoacoustic spectroscopy, electromagnetic sensing and nanomaterial based sensing. The paper primarily focuses on the evolution of non-invasive technology from bench-top equipment to smart wearable devices for personalized non-invasive continuous glucose monitoring in these four methods. With the rapid evolve of wearable technology, all these four methods of non-invasive blood glucose monitoring independently or in combination of two or more have the potential to become a reality in the near future for efficient, affordable, accurate and pain-free diabetes management.

Spinel ferrite-based magnetic nanomaterials have been investigated for numerous biomedical applications, including targeted drug delivery, magnetic hyperthermia therapy (MHT), magnetic resonance imaging (MRI), and biosensors, among others. Recent studies have found that zinc ferrite-based nanomaterials are favorable candidates for cancer theranostics, particularly for magnetic hyperthermia applications. Zinc ferrite exhibits excellent biocompatibility, minimal toxicity, and more importantly, exciting magnetic properties. In addition, these materials demonstrate a Curie temperature much lower than other transition metal ferrites. By regulating synthesis protocols and/or introducing suitable dopants, the Curie temperature of zinc ferrite-based nanosystems can be tailored to the MHT therapeutic window, i.e., 43–46 °C, a range which is highly beneficial for clinical hyperthermia applications. Furthermore, zinc ferrite-based nanostructures have been extensively used in successful pre-clinical trials on mice models focusing on the synergistic killing of cancer cells involving magnetic hyperthermia and chemotherapy. This review provides a systematic and comprehensive understanding of the recent developments of zinc ferrite-based nanomaterials, including doped particles, shape-modified structures, and composites for magnetic hyperthermia applications. In addition, future research prospects involving pure ZnFe₂O₄ and its derivative nanostructures have also been proposed.

Engineering magnetic nanoparticles that combine high heating efficiency with excellent colloidal stability under clinically relevant alternating magnetic field (AMF) conditions remains a major challenge for magnetic hyperthermia. Herein, anisotropic Gd-substituted Fe3O4 nanorods (0-2 mol% Gd) were synthesized by a one-pot solvothermal method to investigate the influence of controlled Gd incorporation on their magnetic hyperthermia performance. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES), confirmed successful Gd incorporation while preserving the predominant spinel Fe3O4 structure, with composition-dependent changes in nanorod morphology and crystal structure. Magnetic measurements of the uncoated nanorods revealed composition-dependent magnetic behavior, with high saturation magnetization (~99-104 emu g-1) retained up to 0.5 mol% Gd before decreasing at higher Gd concentrations. Following PEG-nitroDOPA functionalization, stable aqueous dispersions were obtained for hyperthermia evaluation. Magnetic hyperthermia performance, assessed using complementary AC magnetometry and calorimetry under clinically relevant AMF conditions (20 kA m-1, 200-205 kHz), reached a maximum specific absorption rate of 717-764 W g-1 at 0.75 mol% Gd. These findings demonstrate that controlled low-level Gd substitution, combined with PEG-nitroDOPA functionalization, provides an effective strategy for optimizing the dynamic magnetic response, heating efficiency, and colloidal stability of Fe3O4 nanorods for magnetic hyperthermia.

Magnetic Fe3O4 nanoparticles are widely used in magnetothermal applications, where heating efficiency is governed by magnetic anisotropy. Here, we investigate a template free solvothermal method that decouples shape selection from size tuning, where pre-reaction mixing temperature and duration dictates the formation of Fe3O4 nanospheres or nanorods, and hexadecylamine concentration with solvothermal time enables independent control of rod lengths (~35-80 nm). Transmission electron microscopy (TEM) confirms uniform morphology and X-ray diffraction (XRD) verify single-phase inverse spinel Fe3O4, while Pre-reaction Fourier-transform infrared (FTIR) spectroscopy analysis elucidates the underlying growth mechanism. Magnetization (M-H) measurements revealed that rod shape and size influence coercivity and saturation magnetization and AC magnetometry under clinically safe conditions (200 kHz, 20 kA/m) showed intermediate-sized rods (~45 nm) exhibit the highest heating efficiency (specific absorption rate ~145 W/g), compared to spheres and shorter or longer rods. This reproducible approach provides a rational route for designing anisotropy optimized nanoparticles for magnetothermal biomedical applications.

The magnetic nanorobots, primarily composed of ferromagnetic materials, have been extensively investigated for their potential applications in cellular diagnostics and therapy. However, because of the substantial magnetic remanence exhibited by ferromagnetic materials, the magnetic stability of these nanorobots is a matter of serious concern. Here, we have designed and developed superparamagnetic iron oxide nanoparticles’(SPIONs) functionalized nanorobots (SPIONs-NR), a unique system that is highly stable against magnetic agglomeration. This kind of arrangement of random magnetic moments adhering to the nanorobot’s surface is relatively new and has not been previously explored in terms of fundamental physics and biomedical applications. We have carefully analyzed the various dynamical aspects of these functionalized nanorobots by studying their precession angle as a function of applied frequency at different magnetic fields. Furthermore, these functionalized nanorobots can be controllably maneuvered in the extracellular matrix by the application of rotating magnetic fields of comparatively lower magnitudes (usually <50 G) to selectively target and annihilate malignant tissues via magnetic hyperthermia-induced localized heating, and therefore, making SPIONs-NR promising candidates in modernizing advanced nanomedicine research.