Development of nanoparticle-based contrast agents for x-ray fluorescence computed tomography bioimaging

Nanoparticles (NPs) have become increasingly important across diverse fields, ranging from hybrid materials and sensor technologies to antiviral and antibacterial coatings, as well as numerous biomedical applications, including their role as contrast agents. Their unique physicochemical properties, such as large surface area-to-volume ratio, tunable surface chemistry, and exceptional optical and electronic characteristics, make them highly versatile for various technological and biomedical innovations. Each of these application areas has specific nanoparticle requirements essential for their effective implementation, necessitating tailored approaches to synthesis, functionalization, and characterization.

Recent developments in nanotechnology have significantly advanced the synthesis methods of nanoparticles, enabling precise control over their size, shape, and surface properties. Our research has focused on developing various nanoparticle families tailored specifically for biomedical use, employing bottom-up solution chemical methods. These techniques facilitate the production of highly uniform nanoparticles with well-defined structures, enhancing their performance and reliability in biomedical applications. Furthermore, these nanoparticles are often surface-coated or integrated into larger, micron-sized structures via controlled assembly mechanisms that leverage their inherent surface functionalities. Such approaches not only improve stability and biocompatibility but also optimize nanoparticle interactions within biological systems, enhancing their efficacy in therapeutic and diagnostic applications.

Optimizing surface chemistry is crucial in minimizing processing steps, thereby efficiently achieving desired material properties. Proper surface modification enhances the dispersibility of nanoparticles, prevents agglomeration, and provides selective binding capabilities necessary for targeted applications. These tailored surface modifications significantly impact the biological interactions, biodistribution, and overall effectiveness of nanoparticles within biomedical contexts. The developed nanoparticles have undergone rigorous in-vitro testing and subsequent refinement for in-vivo X-ray fluorescence (XRF) bioimaging applications. XRF bioimaging is a powerful analytical technique providing highly sensitive, quantitative detection of elemental compositions within biological tissues, thus enabling researchers to trace nanoparticle distribution and accumulation in vivo with remarkable accuracy.

In this presentation, I will discuss our recent advancements in nanoparticle design, specifically aimed at leveraging the unique XRF bioimaging facility available in Sweden -one of the few pioneering laboratories globally. This facility allows for the exploration and characterization of nanoparticle-based contrast agents at unparalleled sensitivity and resolution. The talk will outline our progression from first-generation nanoparticles to more advanced core-shell structures, detailing various surface functionalization strategies employed to enhance biocompatibility and targeting efficiency. Additionally, recent results from our in-vitro and in-vivo studies utilizing these innovative nanoparticles will be highlighted, demonstrating their potential for clinical translation and future biomedical applications.

Prof. Muhammet S. Toprak is a materials’ chemist with expertise in functional-materials and material design on the nanoscale. The focus is the development of nanoparticles with controlled size, morphology and surface chemistry, precisely-engineered for the intended applications. He is currently a staff member at the Department of Applied Physics, KTH. Toprak’s research activities have a strong sustainability focus, with special emphasis on applications in energy and biomedicine. A pioneering area is the development of a library of novel nanoparticle-based contrast-agents, and demonstration of their use for emerging x-ray fluorescence bio-imaging. Development of targeted nanoparticles is the objective of on-going research.