Poor biodistribution and accumulation of chemotherapeutics in tumors due to limitations on diffusive transport and high intra-tumoral pressures (Jain RK, Nat Med. 7(9):987–989, 2001) have prompted the investigation of adjunctive therapies to improve treatment outcomes. Hyperthermia has been widely applied in attempts to meet this need, but it is limited in its ability to reach tumors in deeply located body regions. High-intensity radiofrequency (RF) electric fields have the potential to overcome such barriers enhancing delivery and extravasation of chemotherapeutics. However, due to factors, including tumor heterogeneity and lack of kinetic information, there is insufficient understanding of time-resolved interaction between RF fields and tumor vasculature, drug molecules and nanoparticle (NP) vectors. Intravital microscopy (IVM) provides time-resolved high-definition images of specific tumor microenvironments, overcoming heterogeneity issues, and can be integrated with a portable RF device to enable detailed observation over time of the effects of the RF field on kinetics and biodistribution at the microvascular level. Herein, we provide a protocol describing the safe integration of IVM with a high-powered non-invasive RF field applied to 4T1 orthotopic breast tumors in live mice. Results show increased perfusion of NPs in microvasculature upon RF hyperthermia treatment and increased perfusion, release and spreading of injected reagents preferentially in irregular vessels during RF exposure.

中文翻译：

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活体显微镜用于评估暴露于非侵入性射频电场的纳米颗粒的肿瘤灌注。

由于扩散性运输的限制和高的肿瘤内压力，肿瘤中的生物分布不佳和化学疗法的积累不足（Jain RK，Nat Med。7（9）：987-989，2001）促使人们研究辅助疗法以改善治疗效果。热疗已被广泛应用于满足这一需求的尝试中，但是其到达位于深处的身体区域的肿瘤的能力受到限制。高强度射频（RF）电场具有克服此类障碍的潜力，从而增强了化学治疗剂的传递和扩散。然而，由于包括肿瘤异质性和缺乏动力学信息在内的因素，人们对RF场与肿瘤脉管系统，药物分子和纳米颗粒（NP）载体之间时间分辨的相互作用的了解不足。活体显微镜（IVM）可提供特定肿瘤微环境的时间分辨高清图像，克服了异质性问题，并且可以与便携式RF设备集成在一起，以便随时间推移详细观察RF场对人体动力学和生物分布的影响。微血管水平。在这里，我们提供了一个协议，该协议描述了IVM与应用于活小鼠4T1原位乳腺肿瘤的高功率非侵入性RF场的安全整合。结果显示，RF热疗后，微血管中NP的灌注增加，RF暴露期间优先在不规则血管中注入的试剂的灌注，释放和扩散增加。并且可以与便携式RF设备集成在一起，以便随时间推移详细观察RF场在微血管水平上对动力学和生物分布的影响。在这里，我们提供了一个协议，该协议描述了IVM与应用于活小鼠4T1原位乳腺肿瘤的高功率非侵入性RF场的安全整合。结果显示，RF热疗后，微血管中NP的灌注增加，RF暴露期间优先在不规则血管中注入的试剂的灌注，释放和扩散增加。并且可以与便携式RF设备集成在一起，以便随时间推移详细观察RF场在微血管水平上对动力学和生物分布的影响。在这里，我们提供了一个协议，该协议描述了IVM与应用于活小鼠4T1原位乳腺肿瘤的高功率非侵入性RF场的安全整合。结果显示，RF热疗后，微血管中NP的灌注增加，RF暴露期间优先在不规则血管中注入的试剂的灌注，释放和扩散增加。