Cancer is a condition that causes uncontrollable growth of cells within the body. The characteristics of cancer include abnormal differentiation, proliferation, loss of control, infiltration, and metastatic spread [1]. The number of new cases of cancer increases every year, making it one of the world’s deadliest diseases. Cancers are generally classified as leukemia, lymphoma, sarcoma, melanoma, and carcinoma [2]. Lymphoma is a cancer of lymphocytes, whereas leukemia is a type of blood cancer. Sarcoma can appear in a variety of soft or connective tissues, such as bone, muscle, fat, blood vessels, or cartilage. Melanoma is another cancer type that affects and targets the skin pigment cells. The most common type of cancer is carcinoma, which can affect the pancreas, breasts, skin, lungs, or other organs [3]. Cancer is currently treated with surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, stem cell or bone marrow transplant, and hormone therapy. Surgery is the most commonly used and basic method of resecting lesions [4]. A lymphadenectomy can improve the effectiveness of surgery, but incomplete resection still increases the risk of metastasizing cancer. To remove cancerous lesions, the use of chemotherapy involves the use of specific drugs, whereas radiotherapy involves the use of radiation. Targeted therapy delivers a drug directly to cancer cells through a variety of nanocarriers, which makes the treatment more precise and effective [5]. Currently, other cancer therapies are not mature enough to treat cancer accurately.

During the past few years, nanotechnology has been involved in chemotherapy, radiation therapy, and targeted therapy for the treatment of various types of cancer [6]. Nanomaterials are used in modern nanomedicine for developing early diagnostic, detection, and treatment methods ^[7][8][7,8]. Several factors affect the potential biomedical applications, including porosity, size, surface functional groups, electronic properties, zeta potential, and possible interactions ^[9][10][11][9,10,11]. Modern nanomedicine requires optimizing the design and physiochemical characteristics of nanohybrid nanostructures before tackling other significant issues. Especially, advances in hybrid magnetic nanostructures research have had a groundbreaking impact on biomedical applications [12]. Hybrid magnetic nanostructures (MHNs) can be used in magnetic separation, diagnostics, cancer drug delivery, in vivo imaging of cancer, and as contrast agents in MRIs ^[13][14][13,14]. A great deal of effort has been spent on developing ferromagnetic MHNs with controlled parameters ^{[15][16][17][18]}[15,16,17,18]. MHNs are currently being developed and utilized in many clinical applications including cancer diagnosis and treatment. Moreover, cancer diagnosis and treatment can benefit greatly from the use of artificial neural networks (ANN), although this field is still in its infancy [19]. ANN algorithms can be used to optimize nanopharmaceuticals formulations for enhanced transport and targeting of nanomedicines through the prediction of interactions between MHNs nanocarriers, drugs, biological mediators, or cell membranes, as well as the estimation of drug encapsulation efficiency [20]. In addition, ANN can improve clinical outcomes while reducing toxicity, by improving the efficiency of drug delivery and design of the MHNs ^{[21][22][23][24]}[21,22,23,24].

2. Magnetic Nanomaterials and Their Magnetic Hybrids Nanostructures (MHNs)

The advent and development of nanomedicine offer new avenues to improve conventional cancer therapies. Magnetic nanomaterials and hybrid nanostructures are set to hold a lot of interest in the future because of their physicochemical properties, adjustable size and shape, and ease of functionalization. In biomedical applications, iron oxide nanoparticles (IONPs), especially maghemite and magnetite oxides, ferrites are commonly used because of their ability to decompose in the body and release oxygen and iron [25]. They can be easily excreted from the body after degradation through oxygen transport and metabolic systems.

2.1. Morphological Effects of Magnetic Nanomaterials on Cancer Diagnosis and Treatment

When nanoparticles with a diameter of approximately 10 nm are synthesized, they exhibit superparamagnetic properties due to better dispersibility without a magnetic field ^[26][27][26,27]. Cancer therapy relies on the accumulation of these compounds at a target site in the presence of a magnetic field. The size, shape, and surface coating of magnetic nanoparticles can all play a role in their effectiveness for cancer applications such as drug delivery, imaging, hyperthermia, and theranostics ^[18][28][18,28]. The size of magnetic nanoparticles can influence their behavior in cancer therapy. Smaller nanoparticles (~10 nm) tend to be more stable and have a higher surface area-to-volume ratio, which can make them more effective for drug delivery and imaging. However, larger nanoparticles (~50 nm) may be more effective in hyperthermia treatment to kill cancer cells by utilizing heat [29]. The shape of magnetic nanoparticles can also influence their behavior in cancer therapy. For example, rod-shaped nanoparticles may be more effective at inducing hyperthermia than spherical nanoparticles. Magnetic nanoparticles (MNPs) with rod shapes have greater magnetic torque, more intense oscillation, and a greater area involved in the AMF, which results in a higher hyperthermia effect. Moreover, the demagnetization effect indirectly influenced the morphological features through the coercivity of the MNPs. MNPs with rod-shaped shapes had similar saturation magnetic inductions, but their coercivity was 110.42 Gs, which was twice as high as that of spheres (53.185 Gs) [30]. Rod-shaped MNPs consume more energy in vibration than spherical MNPs, i.e., mechanical movement consumes more energy ^[30][31][30,31]. Furthermore, the surface coating of magnetic nanoparticles can influence their stability, biocompatibility, and ability to target cancer cells. For example, nanoparticles coated with biomolecules, such as antibodies or peptides, may be more effective at targeting cancer cells [32]. On the other hand, smaller MNPs can more easily enter into the cancerous tissues and accumulate at the tumor site due to the enhanced permeability and retention (EPR) effect ^[32][33][32,33]. Larger MNPs may have a higher payload capacity but may have lesser diffusivity in the tumor tissue. In drug delivery, magnetic nanoparticles with smaller diameters may be able to target cancer cells and release their payloads, such as chemotherapy drugs or gene therapies, more effectively [34]. This can help to minimize the side effects of treatment and improve the overall effectiveness of the therapy. For example, magnetic nanoparticles can be used to deliver chemotherapy drugs to cancer cells or to deliver gene therapies to modify the expression of specific genes in cancer cells. Magnetic nanoparticles can be used for imaging cancer cells in vivo. Smaller magnetic nanoparticles tend to be more effective at producing high-contrast images of cancer cells and tissues, as they have a higher surface area-to-volume ratio and are more susceptible to the magnetic field ^[35][36][37][35,36,37]. In hyperthermia, larger magnetic nanoparticles may be more effective at inducing heat in cancer cells. This can be achieved by exposing the nanoparticles to an alternating magnetic field, which causes them to oscillate and generate heat. The heat generated by the nanoparticles can then be used to kill cancer cells while minimizing the impact on healthy cells [28]. The quality and effectiveness of MNPs mainly depend on the size and shape of nanoparticles in the final product. The size of the MNPs can be effectively controlled by suitable synthesis methods and reaction conditions. The most important parameters are solvent, pH surfactant, reaction temperature, pressure, residence time, salt source, and precursor. Park et al. reported a large-scale synthesis method for monodisperse nanocrystal synthesis within a size range of 5–22 nm using inexpensive metal salts as reactants in varying solvents [38]. Peng et al. reported the synthesis of self-assembled amorphous core-shell Fe–Fe₃O₄ nanoparticles within a controlled size-range of 2.5–3.5 nm [39]. Overall, the size of magnetic nanoparticles can play a role in their effectiveness for cancer therapy, depending on the specific application. Further research is needed to fully understand the optimal size of magnetic nanoparticles for different cancer therapy applications. Magnetic nanoparticles have been explored as a potential tool for cancer therapy due to their ability to be selectively delivered to cancer cells and then activated using an external magnetic field [40]. The shape of the magnetic nanoparticles can affect their behavior and performance in cancer therapy applications such as hyperthermia and targeted drug delivery. Several morphologies such as spherical, octahedrons, rods, plates, cubes, rings, hexagons, capsules, wires, tubes, and flower-shaped, depending on the reaction conditions, have been reported in the literature for MNPs suitable for different cancer treatment and therapy applications ^[40][41][40,41]. The shape of MNPs is a key factor in determining their effectiveness in cancer therapy. Research has shown that MNPs with different shapes can have different properties, such as magnetic moments, surface area, stability, binding affinity with certain drugs, and their ability to deliver a uniform distribution of drug payload [42]. These properties can influence the behavior of the MNPs in the body, as well as their ability to target and treat cancer cells. For example, rod-shaped MNPs may have a higher binding affinity for certain drugs, whereas sphere-shaped MNPs may have a more uniform distribution of drug payload [43]. Magnetic nanoparticles with spherical shapes penetrate tissues better than rods and wires and can reach cancer cells more easily. They may also be more easily activated using a magnetic field, as the longer shape allows for a stronger interaction with the field [44]. Additionally, rod-shaped MNPs may have a higher binding affinity for certain drugs, whereas sphere-shaped MNPs may have a more uniform distribution of drug payload. On the other hand, spherical particles may be more stable and easier to synthesize and may also have a lower toxicity profile [45]. MNPs that are spherical or ellipsoidal tend to have higher stability and lower toxicity compared to MNPs with more complex shapes [46]. This makes them more suitable for use in cancer therapy, as they are less likely to cause side effects. On the other hand, MNPs with more complex shapes, such as rod- or wire-shaped MNPs, tend to have a higher surface area and a stronger magnetic moment. Nanocube morphologies can have a better response for guided chemo-photothermal therapy [47]. This can make them more effective at targeting and treating cancer cells, as they can be more easily manipulated using external magnetic fields. Hyperthermia damages the cancer cells by supplying heat from an external source. For this purpose, magnetic nanoparticles can be used to induce a current in the particles using an alternating magnetic field, which generates heat [32]. The shape of the nanoparticles can affect their heating efficiency and the distribution of heat within the tissue. For example, elongated nanoparticles have been shown to produce more efficient heating than spherical nanoparticles [48]. Targeted drug delivery is another potential application of magnetic nanoparticles in cancer therapy. The nanoparticles can be coated with drugs and directed to specific locations within the body using a magnetic field [49]. The shape of the nanoparticles can affect the stability of the drug coating and the ability of the nanoparticles to reach their target location. For example, nanoparticles with a high aspect ratio (i.e., those that are long and thin) have been shown to have improved targeting ability and stability compared to spherical nanoparticles. Cao et al. reported high drug loading and release efficiency of hierarchically nanostructured magnetic hollow spheres for ibuprofen suggesting the role of shape in drug delivery applications [50]. In addition to their use in magnetic drug targeting, MNPs can also be used in other cancer treatment approaches, such as photothermal therapy, in which MNPs are used to convert light energy into heat to destroy cancer cells. The size and shape of MNPs will influence their ability to absorb and convert light energy, as well as their distribution in the body. Overall, the shape of MNPs plays a critical role in their effectiveness in cancer therapy. By carefully controlling the shape of the MNPs, researchers can optimize their properties and maximize their potential for use in cancer treatment. In particular, the following sections demonstrate the controlled synthesis of MNPs and their functionalization for cancer diagnosis and therapy toward the development of modern medicine.

2.2. Polymeric–Magnetic Hybrid Nanostructures

Polymer–magnetic hybrid nanostructures have emerged as a promising approach for cancer treatment due to their unique physicochemical properties [51]. These nanostructures are composed of a polymer matrix and magnetic nanoparticles, which can be functionalized with therapeutic agents such as chemotherapy drugs or imaging agents [52]. The magnetic nanoparticles can be attracted to a specific location in the body using an external magnetic field, allowing for targeted delivery of the therapeutic agents to cancerous tumors [53]. Several methods can be used to synthesize polymer–magnetic hybrid nanostructures for cancer treatment. The most common approaches are layer-by-layer assembly, self-assembly, and co-precipitation. Polymer–magnetic hybrid nanostructures are particularly useful for improving the therapeutic efficacy of chemotherapy drugs [54]. In many cases, chemotherapy drugs are insoluble in water, making it difficult to deliver them to cancerous tumors in the desired concentrations. A polymer matrix can improve the solubility of chemotherapy drugs, leading to higher drug concentrations at the tumor site [55]. Furthermore, the polymer matrix can protect chemotherapy drugs from degradation in the body and prevent side effects. Polymer–magnetic hybrid nanostructures can also improve the targeting of therapeutic agents for cancerous tumors [56]. An external magnetic field can be used to attract nanostructures to a specific location in the body by attaching magnetic nanoparticles to their surfaces. Targeted delivery of therapeutic agents can improve the therapeutic efficacy of the treatment by delivering them to the tumor. Recently, CuFe₂O₄@SiO₂-poly(m-phenylene terephthalamide) nanocomposites have been successfully developed by incorporating poly(m-phenylene terephthalamide) onto CuFe₂O₄@SiO₂ nanostructures, as shown in Figure 1a [46]. The SEM images in Figure 1b–d show a unique nanoflower morphology of CuFe₂O₄@SiO₂-poly(m-phenylene terephthalamide) in the present case, which results from the formation of nanoplates oriented in specific directions. EDX spectra also show copper (1.96%), iron (6.17%), and oxygen (62.95%) peaks, which support the presence of CuFe₂O₄ cores, as shown in Figure 1e. Spectral analysis confirms the successful polymerization reaction and the formation of p-phenylene terephthalamide chains (13.12%), nitrogen (6.71%), and oxygen (0.72%). TEOS and CPTMS shells are responsible for the presence of the silicon peak (9.09%). This hybrid CuFe₂O₄@SiO₂-poly(m-phenylene terephthalamide) nanostructure shows potential for magnetic hyperthermia while exhibiting low toxicity, making this material promising for cancer diagnosis and therapy. Polymer–magnetic hybrid nanostructures have been developed for cancer treatment, including magnetic liposomes, magnetic nanoparticles, and magnetic polymeric micelles. Several polymeric materials, including poly(glycolic acid) (PGA), poly(lactic acid) (PLA), and their copolymers PLGA, are bioabsorbable, biocompatible, and biodegradable because their ester links can be hydrolyzed by the human body to form metabolites. A magnetic liposome consists of a phospholipid bilayer that encloses a magnetic nanoparticle core, whereas a magnetic nanoparticle consists of a single magnetic layer. Recently, a novel temperature-responsive magnetite/polymer nanoparticle, developed from iron oxide nanoparticles and a block copolymer of polyethylene oxide and polypropylene oxide (PEO−PPO−PEO), has been developed and appears to be an attractive candidate for the treatment of a wide range of biomedical conditions; in particular, drug delivery [57]. Further, the polyhydroxy poly(ethylene glycol) (mPEG) and poly(lactic acid) (PLGA) block copolymers formed micelles loaded with magnetite as nanocarriers for hydrophobic anticancer drugs [58]. In the future, this micelle could be used as a nanocarrier to deliver hydrophobic drugs or to treat cancer. The polymers and structures they are made from retain their characteristics during the reaction and the entrapment of the drugs, in addition to their biocompatibility and biological properties. This research shows that quercetin-loaded magnetic micelles have appropriate properties in terms of loading of dosages, controlled release, and biocompatibility for use in targeted drug delivery systems. Additionally, through a double emulsion method, PLA–PEG–FA magnetic nanoparticles (nanocarrier) loaded with DOX were prepared, which is a potential cancer-combination chemotherapy and hyperthermia nanosystem [59]. In magnetic polymeric micelles, a polymer core is surrounded by a shell of magnetic nanoparticles. Polymeric nanoparticles are small, spherical particles composed of a polymer shell and a magnetic core. They can be used to deliver cancer therapeutics, such as small interfering RNA (siRNA) molecules, which can help to inhibit the expression of specific genes that are involved in cancer development and progression ^[60][61][60,61]. For example, Jaideve et al. reported the synthesis of multi-functional polymeric-magnetic nanoparticles for the treatment of pancreatic cancer and glioblastoma, respectively ^[62][63][62,63]. Gemcitabine and fluorescent iron oxide encapsulated poly(lactide-co-glycolide) conjugated with antibodies for pancreatic cancer treatment and imaging have been shown to effectively inhibit tumor growth in vivo [62]. Iron oxide-based poly-L-lysine-magnetosomes nanoparticles have been shown to exhibit excellent anticancer properties for magnetic hyperthermia treatment of glioblastoma cancer [63]. Polymeric nanofibers are long, thin fibers composed of a polymer and a magnetic material. They can be used in wound dressing and to deliver cancer therapeutics, such as gene therapies, directly to cancerous tissue. Rahmani et al. reported the fabrication and use of curcumin-loaded poly (vinyl alcohol) (PVA)-graphene oxide (GO)-silver (Ag) nanofibers, synthesized through electrospinning, for wound healing in vitro [64]. Chitosan, polyethylene glycol, and polyvinyl alcohol functionalized MgFe₂O₄ nanoparticles, synthesized by glycol-thermal method, have shown excellent drug delivery of anticancer drugs (doxorubicin) [65]. Taheri-Ledari reported the synthesis of an iron-based nanotherapeutic. The Fe₃O₄ NPs (obtained through the co-deposition technique) were coated with a silica network and encapsulated through PVA taking advantage of H-binding interactions between hydroxyl groups, PVA structure, and Fe₃O₄/SiO₂ surfaces. The therapeutic was reported to be effective in selective drug delivery in ovarian cancer cells [66]. In addition to their use in cancer treatment, polymer–magnetic hybrid nanostructures have also been explored for use in drug delivery and imaging applications. These nanostructures can be functionalized with contrast agents or biomarkers, which can help to visualize cancerous tissue and monitor the progression of the disease through magnetic resonance imaging (MRI) scans. These examples demonstrate the potential of polymer–magnetic hybrid nanostructures for cancer treatment and suggest that these nanostructures may be effective for delivering a wide range of cancer therapeutics to specific areas within the body. Several challenges need to be overcome to fully realize the potential of polymer–magnetic hybrid nanostructures for cancer treatment. One major challenge is the development of effective and stable nanostructures that can withstand the harsh conditions of the body and remain functional over time. Another challenge is the development of effective methods for synthesizing and characterizing these nanostructures, as well as understanding their behavior and interactions within the body. Overall, polymer–magnetic hybrid nanostructures have the potential to revolutionize cancer treatment and diagnosis, and ongoing research in this area is likely to lead to significant advances in the field. However, it is important to note that these nanostructures are still in the early stages of development, and more research is needed to fully understand their behavior and interactions within the body and to optimize their design and function.

2.3. Carbon–Magnetic Hybrid Nanostructures

Carbon–magnetic hybrid nanostructures have emerged as a promising approach for cancer treatment [67]. These nanostructures are composed of both carbon-based materials, such as graphene and carbon nanotubes, and magnetic materials, which allow them to be easily manipulated and targeted to specific areas within the body [68]. The potential applications of carbon–magnetic hybrid nanostructures are in the delivery of cancer therapeutics, detection, and diagnosis of cancer ^[69][70][69,70]. The magnetic material allows the nanostructures to be directed to specific areas within the body using an external magnetic field, whereas the carbon-based material can be used to encapsulate and release the therapeutic agent at a controlled rate [70]. The most widely used carbon-hybrid materials are graphene and carbon nanotubes both of which can be used to deliver cancer therapeutics, such as small interfering RNA (siRNA) molecules, which can help to inhibit the expression of specific genes that are involved in cancer development and progression [71]. Song et al. reported the synthesis of core-shell morphology with 10 nm FeCo and poly(ethylene glycol) decorated graphitic carbon coated on FeCo nanoparticles for enhanced cancer imaging and therapy [72]. Graphitic carbon coating on FeCo prevents FeCo leaching and makes the magnetic nanoparticle more stable, whereas poly(ethylene glycol) coating on functionalized MNP surfaces enhances particle stability, dispersibility, and biocompatibility. Moreover, several hollow carbon nanospheres embedded with γ-Fe₂O₃ and GdPO₄ (Fe–Gd/HCS), dual-Fe nanoparticles embedded within synchronized carbon nanostructures, and co-functionalized mesoporous carbon spheres with γ-Fe₂O₃ and GdPO₄ have also been successfully developed and applied for the integration of magnetic resonance imaging and drug delivery ^{[73][74][75][76][77]}[73,74,75,76,77]. Multiwall carbon nanotubes (MWCN) with magneto-fluorescent carbon quantum dots resulted in synergistic effects toward dual-modal targeted imaging [78]. Poly(acrylic acid) functionalized magnetic multiwall carbon tubes and magnetic-activated carbon particles were synthesized and compared as a nanocarrier for drug delivery and cancer lymphatic-node metastasis treatment. The results suggest poly(acrylic acid) functionalized magnetic multiwall carbon tubes are superior for regression and inhibition of metastasis using gemcitabine loading [79]. Dual functioning magnetic MWCN were also prepared by the addition of iron NPs inside the capillary and surface functionalized with gadolinium using the wet chemical method. The developed magnetic carbon structures can be used in MRI imaging and magnetic hyperthermia applications in cancer treatment [80]. Graphene-oxide hybrid with magnetic material could significantly enhance the efficiency of antitumor efficiencies both in vitro and in vivo through magneto thermal effect and reactive oxygen species-related immunologic effect [81]. These studies demonstrate the potential of carbon–magnetic hybrid nanostructures for cancer treatment and suggest that these nanostructures may be effective for delivering a wide range of cancer therapeutics to specific areas within the body.

2.4. Noble-Metal-Based Magnetic Hybrid Nanostructures

Cancer treatment using noble-metal-based magnetic hybrid nanostructures is a promising area of research that holds great potential for improving the effectiveness of cancer therapies. Noble metals, such as gold, silver, platinum, and palladium, have unique chemical and physical properties that make them attractive for use in medicine. These properties, combined with the ability to manipulate their size and shape at the nanoscale, make them ideal candidates for use in cancer treatment. The morphology of the as-prepared nanostructures depends on the synthesis conditions used. Based on the synthesis techniques (such as sol-gel, vacuum sputtering, ion implantation, laser ablation, vacuum evaporation, electrochemical method, two-phase method, seed growth method, and other techniques as described earlier), different morphologies such as rod-like, film, spherical, hierarchical, powder, and other morphologies can be attained ^{[82][83][84][85]}[82,83,84,85]. The physiochemical properties of noble NPs change as their size and size change ^[83][84][83,84]. A typical example is the change of absorption spectra of gold NPs for spherical (visible region) and rod-shaped (near-infrared region) structures due to the localized surface plasmon resonance effect [86]. Additionally, the unique photothermal and electronic properties of noble metal NPs are a result of the surface-enhanced Raman scattering and metal-enhanced fluorescence effect that can be useful in cancer diagnostic applications ^[87][88][87,88]. The most common structures of noble-metal-based magnetic hybrid nanostructures include nanorods, nanoprisms, nanocages, nanowires, nanocubes, hexagonal sheets, and nanospheres ^{[84][89][90][91][92][93]}[84,89,90,91,92,93]. Gold nanoparticles are being explored to treat tumors by antitumor drug administration, hyperthermia, and angiogenesis inhibition [94]. When exposed to near-infrared light, these nanoparticles have been shown to have a toxic effect on cancer cells. By incorporating these nanoparticles into nanostructures and targeting them in cancer cells, it is possible to use light to trigger the release of the antitumor drug and kill the cancer cells. This approach, known as photothermal therapy, has shown promising results in preclinical studies and is currently being tested in clinical trials. Additionally, gold-based NPs have been utilized in photothermal chemotherapy to kill cancer cells through cell apoptosis and protein denaturation ^[95][96][95,96]. Song et al. reported the synthesis of hybrid gold nanorods decorated on a mixture of doxorubicin and reduced graphene oxide with excellent photothermal effects. Such a hybrid can effectively be used in hyperthermia and drug delivery applications [97]. Silver nanoparticles have been shown to have a toxic effect on cancer cells and can be used to induce cell death through a process known as apoptosis. In addition, silver nanoparticles have been shown to inhibit the growth of cancer cells, making them potentially useful for preventing the spread of cancer. Bian et al. reported the synthesis of silver nanocages decorated on an octreotide template based on peptide-directed silver mineralization. The particle size and morphology were fine-tuned through the addition of silver nitrate resulting in an optimized surface plasmon resonance behavior. The resulting catalysts were reported to have excellent antitumor properties and photothermal efficiency [98]. Additionally, noble-metal-based magnetic hybrid nanostructures are being used in cancer treatment by magnetic resonance imaging (MRI). Sun et al. reported the synthesis of surface-modified ⁶⁴Cu integrated gold nanorods using polyethylene glycol (PEG) and Cu as surface modifiers for enhanced optical imaging and high targetability [99]. In addition to their use in drug delivery and photothermal therapy, noble nanoparticles are also being explored for use in imaging and diagnosis. By incorporating these nanoparticles into contrast agents, it is possible to enhance the visibility of cancerous tumors during imaging procedures such as magnetic resonance imaging (MRI) or computed tomography (CT). This can help doctors to more accurately diagnose and stage cancer, as well as to monitor the effectiveness of treatment. Palladium-based nanostructures have been reported to enhance the photothermal-related process (used in cancer treatment) efficiency and biocompatibility. The inclusion of functionalized palladium structures through polymers significantly improves water dispersion, physiochemical stability, and biocompatibility. Bharathiraja et al. reported the synthesis of chitosan-modified palladium NPs followed by functionalization with RGD peptide resulting in enhanced efficiency of prepared nanoparticles towards near-infrared region imaging for better tumor diagnosis [100]. Hence, noble-metal-based magnetic hybrid nanostructures show great promise for improving the effectiveness of cancer treatment and increasing the chances of survival for cancer patients. Further research is needed to fully understand the potential of these nanostructures and to optimize their use in the clinic. However, these materials have the potential to significantly impact the way that cancer is diagnosed and treated in the future.

2.5. Semiconducting Fluorescent Nanomaterials Magnetic Hybrid Nanostructures

Semiconducting fluorescent nanomaterials are a type of nanomaterial that exhibits fluorescent properties when exposed to light [101]. These nanomaterials can absorb and emit light, making them useful for a variety of applications, including cancer diagnostics ^[102][103][102,103]. The magnetic component of the nanostructure allows it to be guided to the site of the cancer cells using an external magnetic field [104]. Once the nanostructure reaches the cancer cells, the semiconducting fluorescent material can be activated using light, which can then be used to trigger the release of the therapeutic agent ^{[105][106][107]}[105,106,107]. In photodynamic therapy, the light emitted by the fluorescent nanomaterials activates a photosensitizer, which generates reactive oxygen species (ROS) [108]. These ROS can damage the cancer cells and kill them while minimizing the impact on healthy cells. Semiconducting fluorescent nanomaterial magnetic hybrid nanostructures have several attractive properties for use in cancer treatment, due to their high fluorescence efficiency, tunable emission wavelengths, and ability to be functionalized with a variety of biomolecules [109]. There are several examples of semiconducting fluorescent nanomaterials that have been used in magnetic hybrid nanostructures for cancer treatment. Some of these materials include quantum dots, hybrid nanoparticles, carbon dots, graphene quantum dots, and fluorescent dyes [108]. Quantum dots are nanoscale semiconductor particles that can emit light of different colors depending on their size when excited. They have been used in magnetic hybrid nanostructures for cancer treatment because of their high photostability, which means they can retain their fluorescence over a long period. Hybrid nanoparticles can absorb low-energy light and emit higher-energy light, which makes them useful for photodynamic therapy [110]. They have been incorporated into magnetic hybrid nanostructures for cancer treatment because of their ability to generate ROS when excited. Carbon dots are nanoscale particles made of carbon that have been shown to have fluorescent properties [111]. They have been used in magnetic hybrid nanostructures for cancer treatment because of their biocompatibility and low toxicity. Graphene quantum dots are made of graphene, which is a single layer of carbon atoms arranged in a hexagonal lattice [112]. They have been shown to have fluorescence properties and have been incorporated into magnetic hybrid nanostructures for cancer treatment because of their high stability and low toxicity. Fluorescent dyes are organic molecules that can absorb light at one wavelength and emit it at a different wavelength. Magnetic hybrid nanostructures have been developed for cancer treatment because they can be easily synthesized and have a wide range of emission wavelengths. Fluorescence-based imaging techniques and fluorescence-activated cell sorting (FACS) have been used in a variety of cancer diagnostic applications. Lanthanide-doped nanomaterials are materials that are doped with rare earth elements, such as europium or terbium. These materials can emit light when excited and have been explored for use in cancer diagnosis and imaging. Hence, there are many different types of semiconducting fluorescent nanomaterials that have been used in magnetic hybrid nanostructures for cancer treatment, and more are being developed as research in this area continues.

2.6. Biomolecular (Genetic Materials Conjugated) Magnetic Hybrid Nanostructures

In recent years, researchers have been exploring the use of biomolecules conjugated to magnetic hybrid nanostructures for cancer diagnostics ^{[113][114][115]}[113,114,115]. There are several examples of biomolecules, such as genetic materials, that can be conjugated into magnetic hybrid nanostructures for use in cancer diagnostics ^[116][117][116,117]. A new study was developed a magnetic RNA nanoflower delivery system (RNA NF) has been developed to target cancer therapy, as shown in Figure 2a [113]. Nucleic acid can be conveniently separated by introducing magnetic nanoparticles (MNPs) instead of the traditional nucleic acid structure. MNP/RNA NF modified with folic acid (FA) demonstrated excellent biocompatibility. This FA/MNP/RNA NF is small in size, easy to synthesize, biocompatible, and has high binding affinity and selectivity, making it ideal for drug delivery, imaging of cancer cells, and biomolecule detection. Moreover, gemcitabine-loaded magnetic nanoparticles have been successfully used in the treatment of pancreatic cancer targeted treatments, as shown schematically in Figure 2b [114]. In this work, PEGylated Fe₃O₄ nanoparticles with carboxyl groups on the surface were successfully prepared and gemcitabine and peptide (pHLIP) were incorporated to make MET/GEM-MNP-pHLIP. A new cascade treatment for pancreatic cancer utilized MET in an innovative way that could have greatly improved therapeutic outcomes. Biomolecules, such as DNA and proteins, can be conjugated into magnetic hybrid nanostructures to create contrast agents for use in cancer diagnostics. These nanostructures, which are typically composed of a magnetic core surrounded by a shell of biomolecules, can be used to enhance the visibility of cancerous tumors during imaging procedures such as magnetic resonance imaging (MRI) or computed tomography (CT). By incorporating DNA into the nanostructures, it is possible to enhance the sensitivity and specificity of the diagnosis, as the DNA can bind specifically to cancer-associated genes or proteins. RNA, the chemical cousin of DNA, can also be conjugated to magnetic hybrid nanostructures and used to detect specific genetic mutations associated with cancer. Proteins, such as enzymes and antibodies, peptides, and short-chain amino acids, can be conjugated to magnetic hybrid nanostructures and used to detect specific proteins or biomolecules associated with cancer. This can help to diagnose cancer in its early stages, as well as to monitor the effectiveness of treatment. One of the main advantages of using biomolecules conjugated to magnetic hybrid nanostructures for cancer diagnostics is their ability to specifically target cancer cells. By designing the biomolecules to bind to specific receptors or biomarkers found on the surface of cancer cells, it is possible to create contrast agents that are preferentially taken up by tumor cells. This can help to improve the accuracy of cancer diagnosis, as well as to monitor the effectiveness of treatment. Another potential use of magnetic hybrid nanostructures conjugated with biomolecules in cancer diagnostics is using biosensors. These nanostructures can be designed to detect specific biomolecules that are associated with cancer, such as specific proteins or genetic mutations. By detecting these biomolecules, it is possible to diagnose cancer in its early stages, when it is most treatable. Protein-magnetic hybrid nanostructures are also being explored for use in cancer diagnosis. These nanostructures can be designed to specifically target cancer cells and can be used to detect the presence of cancerous tumors with MRI or other imaging techniques. By incorporating proteins into the nanostructures, it is possible to enhance the sensitivity and specificity of the diagnosis, as the proteins can bind specifically to cancer-associated markers or proteins. Overall, the use of biomolecules conjugated to magnetic hybrid nanostructures holds great promise for improving the accuracy and efficiency of a cancer diagnosis.