Tandem mass spectrometry as a bioanalytical platform for characterization of medicinally promising superparamagnetic nanoparticles

Cancer is one of the biggest challenges in public health care. Success in cancer control depends on effective diagnostics and the efficiency of tumor treatment. Therefore, it is evident that special attention should be paid to approaches that allow us to simultaneously detect and cure the tumor, preferably using the same chemical probe. Such an approach exists within the realm of nanomedicine that is rested on the application of nanotechnology to diagnose and treat different diseases. Indeed, nanoparticles, i.e., entities with the size of 1–100 nm, are attractive as imaging and therapeutic agents in oncology due to their unique physical and/or chemical properties.

Superparamagnetic iron oxide nanoparticles (SPIONs) are a class of magnetic nanomaterials that have attracted much research interest due to their stability, low cytotoxicity, biocompatibility, and biodegradability. SPIONs can be effectively used for organ imaging – at least a few were provided the status of approved (by the Food and Drug Administration) contrast agents for magnetic resonance imaging (MRI). Nowadays, the objective is the new, second generation of SPIONs that possess multifunctional characteristics for combined cancer diagnostic and therapeutic applications, for example, MRI-guided anticancer drug delivery, gene delivery, photothermal therapy, photodynamic therapy, or magnetic hyperthermia. Medicinal applications of SPIONs can be governed by their design. The particles’ physical and chemical properties must be rigorously controlled during each synthesis step to fit various applications. An integral part of a SPIONs synthesis is surface modification (coating) and functionalization (attachment of ligands/biomolecules).

The research project is focused on the development of analytical methodologies for the preclinical investigation of novel customized SPIONS of medical importance. Understanding their biodistribution and transformation in the presence of human serum proteins would be essential in obtaining cancer-targeted theranostic nanomaterials.

Various advanced analytical techniques were employed to develop a bioanalytical platform for the characterization of interactions of SPIONs in vivo. Capillary electrophoresis inductively coupled plasma tandem mass spectrometry (CE-ICP-MS/MS) was first applied to characterize commercially available differently charged SPIONs, and then to study their interactions with human serum proteins in simulated physiological conditions. Furthermore, the difficulties related to monitoring interactions of SPIONs with human serum proteins using a method based on electrophoretic separation were demonstrated. Single particle ICP-MS/MS (spICP-MS/MS) was applied to monitor the changes in the nanostructural stability of the SPIONs upon interactions with human serum proteins. The results indicated the reduction of the non-modified SPIONs agglomeration due to the protein corona formation. Moreover, simple methodologies for characterizing the pharmacological properties of novel nanoparticles (such as their toxicity and stability in the physiological environment) based on the sector-field ICP-MS were developed. Additionally, the simple ultraviolet-visible spectroscopy-based methodology utilizing the magnetic properties of nanoparticles was also proposed and used for the initial characterization of potential changes in the selectivity of doped SPIONs.

By intersecting chemistry, biology, and medicine, the research conducted in the frame of this project not only significantly expands knowledge about the interactions of SPIONs with human serum proteins but also provides novel methodologies to study those nanoparticles in the future. The results of the project fulfillment contribute to a better understanding of the biotransformations of SPIONs in the physiological environment and also reveal the limitations of specific tools used to investigate those transformations. The conducted research is an essential step toward understanding nanoparticles’ interactions with human blood protein compounds and, thus, the future design of effective SPIONs with diagnostic and therapeutic properties.

The most significant achievements of the project:

1. Development of a methodology for the initial assessment of the pharmacological properties of the designed iron oxide nanoparticles based on the use of sector-field inductively coupled plasma mass spectrometry (J. Pharm. Biomed. Anal. 189, 2020, 113479)
2. Development of a method for testing the interactions of magnetic iron oxide nanoparticles with selected components of human blood serum containing metals using inductively coupled plasma mass spectrometry (Talanta 229, 2021, 122287)
3. Development of a method for the determination of superparamagnetic iron oxide nanoparticles (SPIONs) under conditions simulating a physiological environment using a hyphenation of capillary electrophoresis and inductively coupled plasma tandem mass spectrometry – CE-ICP-MS/MS (Anal. Bioanal. Chem. 412, 2020, 8145 -8153)
4. Designing a quick and simple method for testing changes in the selectivity of nanoparticles, after doping, to selected analytes – based on the use of superparamagnetic properties of materials and UV/Vis spectrophotometry (Appl. Spectrosc. 75, 2021, 1305-1311)
5. Proposing a method for testing stability changes of superparamagnetic Fe₃O₄ nanoparticles in human blood serum using single particle ICP-MS/MS and demonstrating the effect of protein corona formation on reducing the degree of agglomeration of unmodified nanoparticles (Int. J. Mol. Sci. 23, 2022, 1088)
6. Optimization of the CE-ICP-MS/MS method for studying the interactions of SPIONs with human blood serum proteins (albumin and transferrin) and demonstrating the influence of the magneticity of Fe₃O₄ nanoparticles on the possibility of effective monitoring of the processes mentioned above (Molecules 27, 2022, 8442)