Department of Measurement Technology, Lund University, Sweden.
Anal Chem. 2012 Sep 18;84(18):7954-62. doi: 10.1021/ac301723s. Epub 2012 Aug 28.
Circulating tumor cells (CTC) are shed in peripheral blood at advanced metastatic stages of solid cancers. Surface-marker-based detection of CTC predicts recurrence and survival in colorectal, breast, and prostate cancer. However, scarcity and variation in size, morphology, expression profile, and antigen exposure impairs reliable detection and characterization of CTC. We have developed a noncontact, label-free microfluidic acoustophoresis method to separate prostate cancer cells from white blood cells (WBC) through forces generated by ultrasonic resonances in microfluidic channels. Implementation of cell prealignment in a temperature-stabilized (±0.5 °C) acoustophoresis microchannel dramatically enhanced the discriminatory capacity and enabled the separation of 5 μm microspheres from 7 μm microspheres with 99% purity. Next, we determined the feasibility of employing label-free microfluidic acoustophoresis to discriminate and divert tumor cells from WBCs using erythrocyte-lysed blood from healthy volunteers spiked with tumor cells from three prostate cancer cell-lines (DU145, PC3, LNCaP). For cells fixed with paraformaldehyde, cancer cell recovery ranged from 93.6% to 97.9% with purity ranging from 97.4% to 98.4%. There was no detectable loss of cell viability or cell proliferation subsequent to the exposure of viable tumor cells to acoustophoresis. For nonfixed, viable cells, tumor cell recovery ranged from 72.5% to 93.9% with purity ranging from 79.6% to 99.7%. These data contribute proof-in-principle that label-free microfluidic acoustophoresis can be used to enrich both viable and fixed cancer cells from WBCs with very high recovery and purity.
循环肿瘤细胞（CTC）在实体瘤的晚期转移阶段从外周血中脱落。基于表面标志物的 CTC 检测可预测结直肠癌、乳腺癌和前列腺癌的复发和生存情况。然而，CTC 的数量稀少、大小、形态、表达谱和抗原暴露的变化，使得其可靠检测和特征描述受到了影响。我们开发了一种非接触、无标记的微流控声悬浮方法，通过微流道中的超声共振产生的力，从白细胞（WBC）中分离前列腺癌细胞。在温度稳定（±0.5°C）的声悬浮微通道中实施细胞预对准，极大地增强了区分能力，并实现了 99%纯度下 5μm 微球与 7μm 微球的分离。接下来，我们确定了使用无标记微流控声悬浮来区分和转移来自健康志愿者经红细胞裂解的血液中的肿瘤细胞与 WBC 的可行性，这些血液中添加了来自三种前列腺癌细胞系（DU145、PC3、LNCaP）的肿瘤细胞。对于用多聚甲醛固定的细胞，癌症细胞的回收率范围为 93.6%至 97.9%，纯度范围为 97.4%至 98.4%。在将活肿瘤细胞暴露于声悬浮后，没有检测到细胞活力或细胞增殖的明显损失。对于非固定的活细胞，肿瘤细胞的回收率范围为 72.5%至 93.9%，纯度范围为 79.6%至 99.7%。这些数据初步证明了无标记微流控声悬浮可以从 WBC 中非常高的回收率和纯度中富集活的和固定的癌细胞。
