Wei Jonathan Cj, Cartmill Ian D, Kendall Mark Af, Crichton Michael L
Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia; Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, 2628 CD, Delft, the Netherlands.
Delivery of Drugs and Genes Group (D(2)G(2)), Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia.
J Mech Behav Biomed Mater. 2022 Jun;130:105187. doi: 10.1016/j.jmbbm.2022.105187. Epub 2022 Mar 25.
With the development of wearable technologies, the interfacial properties of skin and devices have become much more important. For research and development purposes, porcine skin is often used to evaluate device performance, but the differences between in vivo, in situ and ex vivo porcine skin mechanical properties can potentially misdirect investigators during the development of their technology. In this study, we investigated the significant changes to mechanical properties with and without perfusion (in vivo versus in vitro tissue). The device focus for this study was a skin-targeting Nanopatch vaccine microneedle device, employed to assess the variance to key skin engagement parameters - penetration depth and delivery efficiency - due to different tissue conditions. The patches were coated with fluorescent or C radiolabelled formulations for penetration depth and delivery efficiency quantification in vivo, and at time points up to 4 h post mortem. An immediate cessation of blood circulation saw mean microneedle penetration depth fell from ∼100 μm to ∼55 μm (∼45%). Stiffening of underlying tissues as a result of rigor mortis then augmented the penetration depths at the 4 h timepoint back to ∼100 μm, insignificantly different (p = 0.0595) when compared with in vivo. The highest delivery efficiency of formulation into the skin (dose measured in the skin excluding leftover dose on skin and patch surfaces) was also observed at this time point of ∼25%, up from ∼2% in vivo. Data obtained herein progresses medical device development, highlighting the need to consider the state and muscle tissues when evaluating prototypes on cadavers.
随着可穿戴技术的发展，皮肤与设备之间的界面特性变得愈发重要。出于研发目的，猪皮常被用于评估设备性能，但体内、原位和离体猪皮机械性能的差异可能会在技术开发过程中误导研究人员。在本研究中，我们调查了有灌注和无灌注（体内组织与体外组织）情况下机械性能的显著变化。本研究聚焦的设备是一种靶向皮肤的纳米贴片疫苗微针设备，用于评估由于不同组织条件导致的关键皮肤接触参数——穿透深度和递送效率——的差异。贴片涂有荧光或碳放射性标记制剂，用于在体内以及死后长达4小时的时间点定量穿透深度和递送效率。血液循环立即停止后，微针平均穿透深度从约100μm降至约55μm（约45%）。随后，尸僵导致下层组织变硬，使4小时时间点的穿透深度增加回约100μm，与体内相比无显著差异（p = 0.0595）。在这个时间点，制剂进入皮肤的最高递送效率（以皮肤中测量的剂量计，不包括皮肤和贴片表面的残留剂量）也被观察到，从体内的约2%升至约25%。本文获得的数据推动了医疗设备的发展，突出了在评估尸体原型时考虑组织状态和肌肉组织的必要性。
