Chemical Engineering Department, Brigham Young University, Provo, Utah.
Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah.
Biotechnol Prog. 2020 Jan;36(1):e2892. doi: 10.1002/btpr.2892. Epub 2019 Sep 10.
Rapid diagnosis of blood infections requires fast and efficient separation of bacteria from blood. We have developed spinning hollow disks that separate bacteria from blood cells via the differences in sedimentation velocities of these particles. Factors affecting separation included the spinning speed and duration, and disk size. These factors were varied in dozens of experiments for which the volume of separated plasma, and the concentration of bacteria and red blood cells (RBCs) in separated plasma were measured. Data were correlated by a parameter of characteristic sedimentation length, which is the distance that an idealized RBC would travel during the entire spin. Results show that characteristic sedimentation length of 20 to 25 mm produces an optimal separation and collection of bacteria in plasma. This corresponds to spinning a 12-cm-diameter disk at 3,000 rpm for 13 s. Following the spin, a careful deceleration preserves the separation of cells from plasma and provides a bacterial recovery of about 61 ± 5%.
快速诊断血液感染需要快速有效地将细菌从血液中分离出来。我们开发了旋转中空圆盘，通过这些颗粒的沉降速度差异将细菌从血细胞中分离出来。影响分离的因素包括旋转速度和持续时间以及磁盘大小。在数十项实验中改变了这些因素，测量了分离出的血浆体积以及分离出的血浆中细菌和红细胞（RBC）的浓度。通过特征沉降长度这一参数对数据进行相关分析，该参数是理想化 RBC 在整个旋转过程中行进的距离。结果表明，特征沉降长度为 20 至 25 毫米可实现最佳的血浆细菌分离和收集。这相当于以 3000 rpm 的速度旋转直径为 12 厘米的圆盘 13 秒。旋转后，小心减速可保持细胞与血浆的分离，并提供约 61 ± 5%的细菌回收率。
