John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA; Wyss Institute Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA; Faculté de Pharmacie, Université de Montréal, Montreal, QC H3T 1J4, Canada.
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA; Wyss Institute Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.
Biomaterials. 2022 Apr;283:121475. doi: 10.1016/j.biomaterials.2022.121475. Epub 2022 Mar 18.
In emergency medicine, blood lactate is a commonly used biomarker of hypoxia (e.g., sepsis, trauma, cardiac arrest) but the median time to obtain the results from a clinical lactate test is 3 h. We recently developed a near-infrared fluorescent blood lactate assay based on a two-step enzymatic cascade in a vesicular reaction compartment. Previously, we reported a response of this assay to lactate-spiked bovine blood after 10 min. To develop a point-of-care test, we optimized this assay in commercial human blood, validated it in fresh capillary blood of healthy volunteers in an institutional review board-approved study, and improved the stability of the formulation. External pH and luminal enzyme concentrations were identified as key parameters of sensor response and kinetics, as they impact transmembrane lactate diffusion and turnover rate. The preparation process was also simplified and the stability was improved to allow storage at 4 °C for at least 5 days. The final formulation exhibited a strong and linear response to lactate-spiked human blood in a clinically relevant range, and accurately quantified a lactate standard at a clinically used cut-off in fresh capillary blood after 2 min. These findings motivate a clinical evaluation of this rapid and easy-to-use lactate assay.
在急诊医学中，血乳酸是一种常用的缺氧生物标志物（例如脓毒症、创伤、心搏骤停），但从临床乳酸检测中获得结果的中位数时间为 3 小时。我们最近基于囊泡反应隔室中的两步酶级联反应开发了一种近红外荧光血乳酸检测法。此前，我们报道了该检测法在 10 分钟后对乳酸掺杂牛血的反应。为了开发即时检测，我们在商业人体血液中对该检测法进行了优化，在机构审查委员会批准的研究中对健康志愿者的新鲜毛细血管血进行了验证，并提高了配方的稳定性。外部 pH 值和腔室酶浓度被确定为传感器响应和动力学的关键参数，因为它们会影响跨膜乳酸扩散和转化率。制备过程也得到简化，稳定性得到提高，允许在 4°C 下储存至少 5 天。最终配方在临床相关范围内对乳酸掺杂的人血表现出强烈而线性的响应，并且在 2 分钟后可在新鲜毛细血管血中准确量化临床使用的截止值处的乳酸标准。这些发现促使对这种快速易用的乳酸检测进行临床评估。
