Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
Anal Chem. 2016 Aug 16;88(16):7938-45. doi: 10.1021/acs.analchem.5b04927. Epub 2016 Aug 3.
The grafting of poly(ethylene glycol) (PEG) onto an SU8 microfilter has been demonstrated for efficient capture and release of circulating tumor cells (CTCs). Previous CTC filters showed low cell release efficiency due to hydrophobic surfaces, even though their capture efficiency was considerable. PEG, a hydrophilic polymeric compound mainly used to form nonfouling thin films on silicon surfaces, induces repulsive force so that the nonspecific adsorption of the surface is incomparably reduced in comparison with unmodified filter surfaces. The effectiveness of PEG-modified CTC filters was verified through lung (H358) and colorectal (SW620) cancer cells spiked, respectively, in phosphate-buffered saline (PBS) and unprocessed whole blood. The modified SU8 filters achieved approximately 37.7% and 22.8% improvement in release efficiency without significant changes in cell viability and capture efficiency. In order to verify the filter's potential for clinical applications, we extended our experiments using cancer patient blood samples. Six blood samples from colorectal and lung cancer patients were processed, and captured CTCs were efficiently released. From these experiments, the present PEG-modified filter captures and releases on average 14 ± 7.4 CTCs/mL, including EpCAM-negative CTCs, which could not be captured by previous single antibody-based methods. The antibody-free isolation with enhanced release efficiency facilitates viable cell retrieval, which is significant to CTC culture and comprehensive molecular study for verifying the mechanism of metastasis and cancer.
已证明将聚乙二醇（PEG）接枝到 SU8 微滤器上可有效捕获和释放循环肿瘤细胞（CTC）。以前的 CTC 过滤器由于疏水性表面，其细胞释放效率较低，尽管其捕获效率相当可观。PEG 是一种亲水性聚合物化合物，主要用于在硅表面形成无污损的薄膜，它会产生排斥力，从而使表面的非特异性吸附与未修饰的过滤表面相比大大减少。通过分别在磷酸盐缓冲盐水（PBS）和未经处理的全血中添加肺（H358）和结直肠（SW620）癌细胞，验证了 PEG 修饰的 CTC 过滤器的有效性。修饰后的 SU8 过滤器在不显著改变细胞活力和捕获效率的情况下，释放效率提高了约 37.7%和 22.8%。为了验证过滤器在临床应用中的潜力，我们使用癌症患者的血液样本扩展了实验。处理了来自结直肠癌和肺癌患者的 6 份血液样本，并有效地释放了捕获的 CTC。从这些实验中，目前的 PEG 修饰的过滤器平均每毫升可捕获和释放 14 ± 7.4 个 CTC，包括以前基于单克隆抗体的方法无法捕获的 EpCAM 阴性 CTC。具有增强释放效率的无抗体分离有助于可存活细胞的回收，这对于 CTC 培养和全面的分子研究，以验证转移和癌症的机制非常重要。
