GFP Reporter Cell Line - SW620

In this study, the SW620-GFP cell line was utilized in a comprehensive magnetic hyperthermia experiment, spanning the entire process from the preparation of a ferrofluid containing folate-coated iron oxide nanoparticles to the execution of in vivo experiments. Physicochemical characterization of these nanoparticles revealed that they exhibit superparamagnetism, possess an average diameter of 12 ± 4 nm with a coating thickness of 2 nm, and demonstrate a high power loss density. Live SW620-GFP cells possess a unique fluorescence emission capability. This characteristic enabled researchers to rapidly analyze cell viability in vitro using epifluorescence microscopy, and to non-invasively monitor tumor size and morphology in vivo using iBox technology. Furthermore, leveraging this imaging technique, the study successfully demonstrated that administering magnetic hyperthermia three times per week over a three-week period effectively reduced tumor volume in mice.

After 24 hours of exposure to a low concentration of SPIONs (0.1 mg/mL), the relative cell viability (RCV) of SW620-GFP cells remained largely unaffected compared to the growth control group. Furthermore, even after co-incubation with higher concentrations of SPIONs (1–3 mg/mL), the RCV decreased only moderately, averaging between 73% and 85% (Figure 1a). This result confirms the low cytotoxicity of these specific SPIONs and suggests their potential suitability for use in magnetic hyperthermia (MH). For the magnetic hyperthermia treatment, SW620-GFP cells were pre-incubated with 2 mg/mL of SPIONs for 2 hours to facilitate the endocytic uptake of the nanoparticles by the cells. Subsequently, an alternating magnetic field with a frequency of 530 kHz was applied, and the temperature was maintained within a target range of 39-48 °C for 20 minutes by manually adjusting the magnetic field amplitude. The results indicated that maintaining the final temperature at ≤41 °C had virtually no negative impact on cell RCV; however, when the temperature rose to 43 °C, the RCV plummeted to less than 40% (Figure 1b). Further increases in temperature resulted in an even more pronounced decline in RCV; when the temperature reached 48 °C, cell viability was almost completely abolished, with the RCV dropping to a mere 4%. Additionally, no significant difference in RCV was observed between the two control groups, a finding attributed to the fact that the magnetic field itself does not interact with cells that have not internalized SPIONs.

Figure 1. (a) RCV of SW620-GFP cells after incubation for 24 hours in the presence of varying concentrations of SPIONs; (b) RCV of SW620-GFP cells exposed to 2 mg/mL SPIONs and heated to 39-48 °C via magnetic field irradiation. (Rosales S, et al., 2024)