Biodegradable nano-films for capture and non-invasive release of circulating tumor cells

Abstract

Selective isolation and purification of circulating tumor cells (CTCs) from whole blood is an important capability for both clinical medicine and biological research. Current techniques to perform this task place the isolated cells under excessive stresses that reduce cell viability, and potentially induce phenotype change, therefore losing valuable information about the isolated cells. We present a biodegradable nano-film coating on the surface of a microfluidic chip, which can be used to effectively capture as well as non-invasively release cancer cell lines such as PC-3, LNCaP, DU 145, H1650 and H1975. We have applied layer-by-layer (LbL) assembly to create a library of ultrathin coatings using a broad range of materials through complementary interactions. By developing an LbL nano-film coating with an affinity-based cell-capture surface that is capable of selectively isolating cancer cells from whole blood, and that can be rapidly degraded on command, we are able to gently isolate cancer cells and recover them without compromising cell viability or proliferative potential. Our approach has the capability to overcome practical hurdles and provide viable cancer cells for downstream analyses, such as live cell imaging, single cell genomics, and in vitro cell culture of recovered cells. Furthermore, CTCs from cancer patients were also captured, identified, and successfully released using the LbL-modified microchips.

Cell Isolation and Recovery Using Hollow Glass Microspheres Coated with Nanolayered Films for Applications in Resource-Limited Settings

“…30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 For applications beyond purification in blood, it is worth noting that a 97% recovery efficiency was achieved for PC-3 cells in a mixture of PC-3 (10,000 /mL) and CCRF-CEM cells (a nonEpCAM expressing cell line, 10,000 /mL) spiked in PBS. Recovery efficiency was only slightly decreased to 92% if the HGMSs was not modified with a PEG layer (Fig.…”

“…Therefore, relatively high shear washing steps compared to flow rates used during capture are integrated into HB-Chip cell processing. 30 In contrast, HGMS-based cell isolation cannot readily integrate robust washing regulated by controlled flow; therefore, additional modification of the HGMS films is needed to minimize non-specific cell attachment.…”

“…Here we use biotin-grafted anti-EpCaM antibodies as a model capture antibody commonly used for cancer cell capture 30,47. The density of anti-EpCAM antibodies conjugated on the microsphere surface is a critical parameter for successful cell capture.…”

Functional Studies on Viable Circulating Tumor Cells

“…Cell surface proteins could be used for an antibody-based enrichment step to attach CTCs [positive selection by use of the epithelial cell adhesion molecule (EpCAM), the cell surface marker that is most frequently used for positive enrichment of epithelial CTCs]. In light of the capacity of tumor cells to undergo epithelial-to-mesenchymal transition, the capture of CTCs may not rely solely on Ep-CAM expression, but may require additional targets [e.g., epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), mucin 1 (MUC1)] (7,8 ). Obviously, intracellular proteins cannot be used, as the cells must remain intact.…”

Molecular profiling of single circulating tumor cells from lung cancer patients

“…Many other innovative platforms (2) leverage various physical and biochemical properties of CTCs for highly sensitive and efficient enrichment (2), encompassing improved epithelial cell adhesion molecule (EpCAM)-based capture [e.g., CTC Chip (4), HB-Chip (5), μNMR (6), MagSweeper (7), and MagSifter (8)], size-selective capture [e.g., Cluster-Chip (9), ISET (2,10), and Vortex technologies (11)], inertial-based capture [e.g., iChip platform (12)], nanomaterials-based capture [e.g., nanofilms (13), NanoVelcro (14), and functionalized graphene oxide nanosheets (15)], and image-based cytometry [e.g., HD-CTC (16)]. …”