Poster O6 - Superparamagnetic Nanoclusters for Selective Isolation of Target Molecules from Complex Solutions via Template-Assisted Nucleation and Clustering Process

Introduction: Magnetic nanoparticles are extensively employed in a range of biomedical fields such as MR imaging, targeted drug delivery, and molecular diagnostics. Notably, their role in magnetic separation offers substantial promise for pre-treatment techniques aimed at isolating specific entities such as protein biomarkers and pathogens from biofluids. Nevertheless, the selective isolation of biomarkers within blood presents significant challenges due to the presence of complex components including abundant blood cells, cell-free DNA, and various proteins. To selectively isolate target substances present in trace amounts from blood, a fluid composed of various components, there is a need for magnetic nanoparticles that possess superior magnetic property and have a large surface area for surface modification with ligand.

Materials and

Methods: We have developed superparamagnetic nanoclusters through a template-assisted nucleation and clustering process based on conventional hydrothermal synthesis. The extended reaction time allowed for high crystallinity, and the individual nanocrystals, each less than 20 nm in size, formed cluster structures through a self-assembly process, enabling the synthesis of superparamagnetic nanoparticles. The synthesis process involves the thermal expansion of polymer templates and the growth of individual primary nanoclusters, allowing the formation of magnetic nanoparticles larger than 200 nm. Additionally, these nanoparticles achieve a saturation magnetization of 100 emu/g, the maximum value known for magnetite with a size of 200 nm.

Results, Conclusions, and Discussions: This study demonstrated that superparamagnetic nanoclusters, modified with antibodies, can effectively concentrate and detect granzyme B, a biomarker typically present in blood at challenging pg/ml levels. Under continuous flow, the superparamagnetic nanocluster-granzyme B complexes were isolated using a magnetic field, facilitating the use of large volume samples. This separation process not only isolates but also concentrates the samples, achieving an enrichment of up to 2000 times depending on the sample volume, and elevating the detection limit to fg/ml levels. Furthermore, this approach has shown that red blood cell membrane-coated superparamagnetic nanoclusters can selectively capture bacteria in whole blood, thereby enhancing blood purification through magnetic isolation and concentration. These nanoclusters effectively isolate bacteria in complex bloodstreams, even under very high flow rates, while preserving their magnetic properties post-coating. The successful isolation of pathogen-superparamagnetic nanocluster complexes was verified in vivo within a sepsis model, demonstrating rapid isolation at flow rates up to 5000 times faster than previous studies, along with significant improvements in various hematological parameters 12 hours post-administration. These findings suggest that the developed magnetic nanocluster not only supports enhanced detection of trace biomarkers but also facilitates efficient pathogen removal from large blood volumes. The implications of these capabilities extend to potential diagnostic and therapeutic applications, similar to hemodialysis, for blood cleansing and health monitoring, thus offering a promising avenue for advancing medical diagnostics and treatment strategies.

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