Ruta Sergiu, Fernández-Afonso Yilian, Rannala Samuel E, Morales M Puerto, Veintemillas-Verdaguer Sabino, Jones Carlton, Gutiérrez Lucía, Chantrell Roy W, Serantes David
College of Business, Technology and Engineering, Sheffield Hallam University UK
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza and CIBER-BBN Spain
Nanoscale Adv. 2024 Jun 25;6(16):4207-4218. doi: 10.1039/d4na00383g. eCollection 2024 Aug 6.
Accurate knowledge of the heating performance of magnetic nanoparticles (MNPs) under AC magnetic fields is critical for the development of hyperthermia-mediated applications. Usually reported in terms of the specific loss power (SLP) obtained from the temperature variation (Δ) time () curve, such an estimate is subjected to a huge uncertainty. Thus, very different SLP values are reported for the same particles when measured on different equipment/in different laboratories. This lack of control clearly hampers the further development of nanoparticle-mediated heat-triggered technologies. Here, we report a device-independent approach to calculate the SLP value of a suspension of magnetic nanoparticles: the SLP is obtained from the analysis of the peak at the AC magnetic field on/off switch of the Δ(time) curve. The measurement procedure, which itself constitutes a change of paradigm within the field, is based on the heat diffusion equation, which is still valid when the assumptions of Newton's law of cooling are not applicable, as (i) it corresponds to the ideal scenario in which the temperature profiles of the system during heating and cooling are the same; and (ii) it diminishes the role of coexistence of various heat dissipation channels. Such an approach is supported by theoretical and computational calculations to increase the reliability and reproducibility of SLP determination. Furthermore, the new methodological approach is experimentally confirmed, by magnetic hyperthermia experiments performed using 3 different devices located in 3 different laboratories. Furthermore, the application of this peak analysis method (PAM) to a rapid succession of stimulus on/off switches which results in a zigzag-like Δ(), which we term the zigzag protocol, allows evaluation of possible variations of the SLP values with time or temperature.
准确了解交流磁场下磁性纳米颗粒（MNPs）的加热性能对于热疗介导应用的发展至关重要。通常根据从温度变化（Δ）-时间（）曲线获得的比损耗功率（SLP）来报告，这样的估计存在很大的不确定性。因此，在不同设备上/在不同实验室测量时，对于相同的颗粒会报告非常不同的SLP值。这种缺乏控制显然阻碍了纳米颗粒介导的热触发技术的进一步发展。在此，我们报告一种与设备无关的方法来计算磁性纳米颗粒悬浮液的SLP值：SLP是通过分析Δ（时间）曲线的交流磁场开/关切换时的峰值获得的。该测量程序本身构成了该领域内的一种范式转变，它基于热扩散方程，当牛顿冷却定律的假设不适用时该方程仍然有效，因为（i）它对应于加热和冷却期间系统温度分布相同的理想情况；以及（ii）它减少了各种散热通道共存的作用。这种方法得到了理论和计算计算的支持，以提高SLP测定的可靠性和可重复性。此外，通过在3个不同实验室使用3种不同设备进行的磁热疗实验，对这种新的方法进行了实验验证。此外，将这种峰值分析方法（PAM）应用于快速连续的刺激开/关切换，这会导致锯齿状的Δ（），我们称之为锯齿状协议，从而可以评估SLP值随时间或温度的可能变化。
