发表机构
University of South Florida; Texas Tech University; The University of Texas at Arlington（南佛罗里达大学; 德克萨斯理工大学; 阿灵顿得克萨斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用磁粒子光谱法检测与SKOV3卵巢癌细胞结合的锌铁氧体纳米颗粒，通过高次谐波分析揭示其弛豫动力学，证明MPS可用于磁性细胞标记与追踪。
AI 中文摘要
磁粒子光谱法（MPS）能够通过高次谐波灵敏地检测磁性纳米颗粒（MNPs）并表征其动态磁化过程。本研究合成了柠檬酸盐功能化的30 nm立方Zn0.4Fe2.6O4（ZFO）MNPs，并利用MPS研究了其与SKOV3卵巢癌细胞的结合情况。ZFO MNPs具有结晶尖晶石结构，平均水动力直径为39.4 nm，室温磁化强度高，矫顽力低，并带有柠檬酸盐相关的表面官能团。Live/Dead成像显示，在浓度高达0.5 mg/mL下暴露24小时后具有良好的细胞相容性，而明场显微镜显示细胞相关纳米颗粒的积累呈浓度依赖性。使用分散在去离子水和琼脂中的ZFO MNPs作为相对不受限和强受限的参考状态，比较了两种MPS驱动场。7.75 kHz、20 mT条件比11.37 kHz和10 mT保留了更多高次谐波，并在两种状态之间产生了更大且与阶次相关的光谱分离；因此被选用于细胞测量。在ZFO暴露并去除未结合纳米颗粒后，MPS在含有0.1、1和2×10^6个SKOV3细胞的样品中检测到细胞相关MNPs。第3、5和7次谐波振幅随细胞数量成比例增加，幂律指数为1.03-1.09。我们还报告，来自1和2×10^6细胞样品的大多数归一化谐波比介于水和琼脂参考之间，表明细胞环境中布朗旋转受到部分限制。这些发现表明，MPS可以检测细胞相关MNPs，同时提供关于其系综平均物理限制的补充光谱信息，支持其在磁性细胞标记和细胞追踪研究中的应用。
英文摘要
Magnetic particle spectroscopy (MPS) enables sensitive detection of magnetic nanoparticles (MNPs) and characterization of their dynamic magnetization through higher-order harmonics. Here, we synthesized citrate-functionalized, 30 nm cubic Zn0.4Fe2.6O4 (ZFO) MNPs and investigated their association with SKOV3 ovarian cancer cells using MPS. The ZFO MNPs exhibited a crystalline spinel structure, a mean hydrodynamic diameter of 39.4 nm, strong room-temperature magnetization, low coercivity, and citrate-associated surface functional groups. Live/Dead imaging indicated good cytocompatibility after 24 h exposure at concentrations up to 0.5 mg/mL, while bright-field microscopy showed concentration-dependent cell-associated nanoparticle accumulation. Two MPS drive fields were compared using ZFO MNPs dispersed in DI water and agar as relatively unrestricted and strongly confined reference states. The 7.75 kHz, 20 mT condition retained more higher-order harmonics than 11.37 kHz and 10 mT and produced a larger and order-dependent spectral separation between the two states; it was therefore selected for the cellular measurements. After ZFO exposure and removal of unbound nanoparticles, MPS detected cell-associated MNPs in samples containing 0.1, 1, and 2x10^6 SKOV3 cells. The 3rd-, 5th-, and 7th-harmonic amplitudes increased proportionally with cell number, with power-law exponents of 1.03-1.09. We also report that most normalized harmonic ratios from the 1- and 2x10^6-cell samples fell between the water and agar references, indicating partial restriction of Brownian rotation in the cellular environment. These findings demonstrate that MPS can detect cell-associated MNPs while providing complementary spectral information about their ensemble-averaged physical confinement, supporting its application in magnetic cell labeling and cell-tracking studies.
Comments22 pages, 9 figures, 1 TOC graphic
