Indoor Environment Engineering Research Center of Fujian Province, Fujian University of Technology, Fuzhou, Fujian, 350118, China.
School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia.
Int J Numer Method Biomed Eng. 2019 Jul;35(7):e3215. doi: 10.1002/cnm.3215. Epub 2019 May 29.
The scarcity of regional deposition data in distal respiratory airways represents an important challenge for current toxicology and pharmacology research. To bridge this gap, a realistic airway model extending from nasal and oral openings to distal bronchial airways with varying pathway length was built in this study. Transport and deposition characteristics of naturally inhaled ultrafine particles (UFPs) ranging from 1 to 100 nm were numerically investigated, and effects of different inhalation scenarios were considered. To enable intercase particle deposition comparison, an adjusted parameter, unified deposition enhancement factor (UDEF), was proposed for quantifying the localised deposition concentration. Results show that compartment particle deposition peaked around the ultrafine end of the considered size range, and it dropped rapidly with the increase of particle size. Different inhalation modes caused notable deposition changes in the extrathoracic region, while its effects in the TB airway are much less. For UFPs larger than 10 nm, predicted deposition efficiencies in all compartments are all at lowest levels among considered particle size range, implying UFPs ranging from 10 to 100 nm can travel through the whole respiratory airway model and escape to the alveolar region. Furthermore, high enhancement factors were observed at the vicinity of most bifurcation apexes, and more even UDEF distribution was observed from 1-nm particle cases. While for 100-nm cases, the deposited particles tend to concentrate at few "hot spots" (areas of high deposition concentration in relation to surrounding surfaces) with greater UDEF in the tracheobronchial airway.
在远端呼吸气道中，区域性沉积数据的稀缺性是当前毒理学和药理学研究的一个重要挑战。为了弥补这一空白，本研究构建了一个从鼻腔和口腔延伸到远端支气管气道的具有不同路径长度的现实气道模型。本文数值研究了从 1 到 100nm 的自然吸入超细颗粒（UFPs）的传输和沉积特性，并考虑了不同吸入情景的影响。为了实现病例间颗粒沉积的比较，提出了调整参数——统一沉积增强因子（UDEF），用于量化局部沉积浓度。结果表明，在考虑的粒径范围内，各腔室的颗粒沉积峰值出现在超细端附近，随着粒径的增加，沉积迅速下降。不同的吸入模式会导致胸腔外区域的沉积发生显著变化，而对 TB 气道的影响则较小。对于粒径大于 10nm 的 UFPs，所有腔室的预测沉积效率均处于所考虑粒径范围内的最低水平，这意味着粒径在 10nm 至 100nm 之间的 UFPs 可以穿过整个呼吸道模型并逃到肺泡区域。此外，在大多数分叉顶点附近观察到了较高的增强因子，并且从 1nm 颗粒的情况中观察到了更均匀的 UDEF 分布。然而，对于 100nm 颗粒的情况，沉积的颗粒往往会集中在少数“热点”（与周围表面相比沉积浓度较高的区域），在气管支气管气道中，UDEF 更大。
