Synthesis of PEG-coated magnetic nanoparticles and micro-magnet arrays for magnetically assisted cell manipulation

Polyethylene glycol-coated magnetic nanoparticles (PEG-Fe3O4 NPs) exhibit significant potential for lab-on-a-chip and bio-MEMS applications due to their superparamagnetic characteristics, stability, and biocompatibility. This study involved the synthesis of Fe3O4 NPs via the coprecipitation method, followed by functionalization with PEG to improve dispersion and prevent aggregation. XRD, FTIR, SEM, and VSM were used to validate the crystalline structure, surface modifications, morphology, and magnetic responsiveness of the NPs. XRD indicated an average crystallite size of ∼14 nm, while SEM analysis revealed larger mean particle diameter of ∼44 nm. SH-SY5Y cells were tagged with PEG-Fe3O4 NPs (0.1–100 μg/ml), cell uptake confirmed using Prussian Blue Staining together with Neutral Red Counterstaining. The cytocompatibility of the PEG-Fe3O4 NPs in the optimized range was confirmed by cell viability assays, which demonstrated viability at concentrations of (0.1–100 μg/ml) and moderate declines at higher concentrations. Additionally, this work introduced a new, efficient method for fabricating ordered arrays of Nd-Fe-B and Sr-Ferrite (SrFe12O19) microparticles (MPs) patterns, which were prepared from SU-8 photoresist by using the photolithography technique, to produce local gradients. Integration of PEG-Fe3O4 NPs with micro-magnets creates robust platform for magnetophoretic manipulation. This study primarily focused on the structural characterization and biological validation of PEG-Fe3O4 NPs, including cell viability assessments and SH-SY5Y labeling studies. Future research will integrate patterned micro-magnets into microfluidic channels to evaluate the capture and efficiency of labeled cells by introducing them into the microfluidic channel. These findings provide a solid foundation for developing advanced bio-MEMS applications in cancer diagnosis and targeted therapy.