Since the expected therapeutic results of ischemic stroke are strictly time dependent, early and accurate diagnosis as well as short intervals between diagnosis and treatment are key factors for the survival of stroke patients. In this study, we fabricated platelet (PLT) membrane-derived biomimetic nanobubbles (PNBs) for timely perfusion intervention and ultrasound imaging of acute ischemic stroke.

Methods: The PNBs are fabricated by sonication-assisted reassembly of repeatedly freeze-thawed live platelet-derived PLT membrane vesicles (PMVs). The TEM, SEM, EDS and DLS were used to analyze the morphology and physicochemical properties of PNBs. The HPLC and LC-MS/MS were applied to confirm the lipid and protein compositions of PNBs. The in vitro macrophage uptake and platelet aggregation of PNBs were designed to examine the immune escape and thrombotic response characteristics. Furthermore, based on a photothrombotic ischemic stroke mouse model, the biodistribution, stroke microvascular network change, as well as cerebral blood flow of PNBs were studied by using near-infrared fluorescence imaging, multimodal optical imaging, and full-field laser perfusion imager. Finally, we assessed the brain ultrasound imaging of PNBs with a high-resolution micro-imaging system using both B-mode and contrast mode.

Results: The natural lipid and protein components isolated from PLT membrane endow the PNBs with accurate lesion-targeting ability. The preferentially accumulated PNBs exhibit microvascular bio-remodeling ability of the stroke lesion, which is critical for recanalization of the obstructed vessels to protect the neural cells around the ischemic region of the stroke. Furthermore, with the increased accumulation of PNBs clusters in the lesion, PNBs in the lesion can be monitored by real-time contrast-enhanced ultrasound imaging to indicate the severity and dynamic development of the stroke.

Conclusions: In summary, platelet membrane-based nanobubbles for targeting acute ischemic lesions were developed as microvascular recanalization nanoformulation for acute ischemic stroke lesion theranostics. This biomimetic PNBs theranostic strategy will be valuable for ischemic stroke patients in the future.

Keywords: Platelet membrane, nanobubbles, stroke targeting, neuroprotection, ultrasound imaging

由于缺血性中风的预期治疗结果严格依赖于时间，因此早期准确的诊断以及较短的诊断和治疗间隔是中风患者生存的关键因素。在这项研究中，我们制造了血小板（PLT）膜衍生的仿生纳米气泡（PNB），用于急性缺血性中风的及时灌注干预和超声成像。

方法： PNB 是通过超声辅助重新组装反复冻融的活血小板衍生的 PLT 膜囊泡 (PMV) 来制造的。使用TEM、SEM、EDS和DLS来分析PNB的形貌和物理化学性质。应用 HPLC 和 LC-MS/MS 来确认 PNB 的脂质和蛋白质组成。体外巨噬细胞摄取和PNBs的血小板聚集旨在检查免疫逃逸和血栓反应特征。此外，基于光血栓缺血性中风小鼠模型，利用近红外荧光成像、多模态光学成像和全场激光灌注成像仪研究了PNB的生物分布、中风微血管网络变化以及脑血流。最后，我们使用 B 模式和对比模式通过高分辨率显微成像系统评估了 PNB 的脑部超声成像。

结果：从PLT膜中分离出的天然脂质和蛋白质成分赋予PNBs精确的病变靶向能力。优先积累的PNB表现出中风病灶的微血管生物重塑能力，这对于阻塞血管的再通以保护中风缺血区域周围的神经细胞至关重要。此外，随着病灶中PNB簇积累的增加，可以通过实时超声造影监测病灶中的PNB，以指示中风的严重程度和动态发展。

结论：总而言之，针对急性缺血性病变的基于血小板膜的纳米气泡被开发为用于急性缺血性中风病变治疗诊断的微血管再通纳米制剂。这种仿生 PNB 治疗诊断策略对于未来的缺血性中风患者将很有价值。

关键词：血小板膜，纳米气泡，中风靶向，神经保护，超声成像