971 emu/g for rMNPs. The coercivity of the rod-shaped MNPs was 110.42 Gs, while the coercivity of the spherical MNPs was 53.18 Gs. Figure 2 TEM images of spherical (left) and rod-shaped (right) iron oxide MNPs used. Thermal effect of AMF During the AMF treatment, neither type of MNPs leads to an obvious temperature rise. This is because of the low power and low frequency of the device relative to the commonly used thermal therapy device [18, 19]. CHIR-99021 clinical trial When 0.1 g

solid MNPs powder was placed in the center of the AMF-generating device, the maximal temperature rise was 1.7°C. It is known that the required temperature for irreparable cell damage during hyperthermia therapy should be no less than 43°C [20, 21]. Additionally, the relative small mass fraction of MNPs was used in the treated unit. Therefore, this marginal temperature rise suggested that the thermal injury could be neglected in this study. Cell cytotoxicity and characterization of cell loading HeLa cells incubated with either spherical or rod-shaped MNPs exhibited no signs of toxicity at any of the three concentrations. Meanwhile, the rMNPs promoted cell proliferation slightly,

as like as the results of previous research by Tomitaka et al.[22]. After 20 h incubation in medium containing MNPs, the amount of MNP intake by the single cell reached the peak. sMNPs (85%) and rMNPs (89%) were loaded by HeLa cells at the concentration of 100 μg/mL. As shown in Figure 3a,b, abundant MNPs were embedded in the HeLa cell membrane. The majority of the MNPs are distributed evenly while the minority Methane monooxygenase forming

clusters. Optical images (Figure 3c,d) CDK inhibitor showed that majority of MNPs are distributed on the cellular surfaces. TEM images of cell ultramicrocuts (Figure 3e,f) revealed that part of the MNPs were incorporated into the cells’ cytoplasma and were distributed evenly. Figure 3 Images of MNP-loaded HeLa cell. (a,b) SEM images of HeLa cell membranes showing MNPs loading. (c,d) Optical microscopy images of semi-thin sections (500 nm thicker than the MNPs’ diameter). (e,f) TEM images of cell ultramicrocuts (50 nm thinner than the diameter or width of MNPs); The arrows in (f) point to cut rod-shaped MNPs in the ultramicrocuts. Cell viability after AMF treatment In this study, AMF treatment was approved of an obvious inactivation effect on MNP-loaded HeLa cells. As shown in Figure 4, forced vibration of MNPs mechanically destroys the cell membrane structure, leading to apoptosis. After AMF treatment, the relative viabilities of the MNP-loaded cells generally decreased. The effect of mechanical damage was not fully shown at the beginning period of AMF treatment. However, the efficiency increased because of the cumulative effect of mechanical oscillations. Hence, longer AMF treatment period is required in practice. Meantime, the amount of MNP loading heavily influenced the inactivation effect as well.