Microfluidic channel-coupled 3D quartz nanohole arrays for high capture and release efficiency of BT20 cancer cells

Abstract

Nanostructured materials, such as silicon nanowires, quartz nanostructures, and polymer-modified nanostructures, are a promising new class of materials for the capture and enumeration of very rare tumor cells, including circulating tumor cells (CTCs), to examine their biological characteristics in whole blood of cancer patients. These cells can then be used for transplantation, anti-tumor cell therapy, and cell-secreted protein studies. It is believed that 3-dimensional (3D) nanostructured substrates efficiently enhance cell capture yields due to the increased local contacts between the 3D nanostructures and extracellular extensions of the tumor cells. Recent studies have been performed with enhanced cell capture yields thanks to various nanostructured platforms; however, there remains an urgent need both to capture and release viable rare tumor cells for further molecular (i.e., protein) analysis and to develop patient-specific drugs. Here, we first demonstrate that our 3D quartz nanohole array (QNHA) tumor cell capture and release system allows us not only to selectively capture rare tumor cells, but also to release the cells with high capture and release rates. This system was developed using streptavidin (STR)-functionalized QNHA (STR-QNHA) with a microfluidic channel. Our system has ideal cell-separation yields of as high as 85-91% and high release rates of >90% for the BT20 cell line. We suggest that the use of a microfluidic channel technique coupled with a STR-QNHA cell capture and release chip (STR-QNHA cell chip) would be a powerful and simple process to evaluate the capture, enumeration, and release of CTCs from patient whole blood for studying further cell therapy and tumor-cell-secreted molecules.

Nanostructured Substrates for Detection and Characterization of Circulating Rare Cells: From Materials Research to Clinical Applications

“…The anti-EpCAM-functionalized HNT-coating substrate had a CTC capture yield of 92%. Nanoporous substrates, e.g., porous poly(aminophenylboronic acid) (polyAPBA) nanostructured substrates, [180] nanoporous anodic aluminum oxide-embedded substrates, [181] quartz nanohole arrays, [182] and bionic TiO 2 inverse opal photonic crystal (IOPC) structure, [183] have also been used to capture CTCs with enhanced performance. For instance, porous polyAPBA nanostructured substrates were prepared on solid substrates by altering the nucleation and growth rates for polymerization of 3-aminophenylboronic acid (3-APBA) monomer.…”

“…Trypsin was used to recover MCF7 cancer cells that were captured on TiO 2 nanosisal-like substrates (Figure 12a) [212] and BT20 cancer cells that were captured by a quartz nanohole-embedded microfluidic system with a release efficiency of 90% and cell viability of 75%. [182] However, trypsinization is a nonspecific cell retrieval strategy that often results in low purity of CTCs in the final cell suspension. The duration of trypsinization should be carefully controlled since prolonged trypsinization leads to cell membrane damage and decreased viability.…”

Tunable Subradiant Mode in Free-Standing Metallic Nanohole Arrays for High-Performance Plasmofluidic Sensing

“…The integration of plasmonics and microfluidics has been an object of fascination in recent years, which offers portable, cheap, label-free, real-time, and high-throughput sensing to meet the demands of next-generation modern biosensors. − In plasmofluidic sensors, the microfluidic channels provide both a reduction of the sensing volume and improved transportation of the analyte fluid to the sensing area, enabling faster, higher throughput, and more sensitive detection. Among various plasmofluidic sensing devices, the marriage of metallic nanohole arrays (NAs) and fluidics has evolved rapidly because of the desirable properties of metallic NAs. − Metallic NAs working as plasmonic sensors are based on their ability to support extraordinary optical transmission (EOT), which is sensitive to the changes in the local refractive index, enabling real-time label-free molecular sensing. − Being plasmonic sensors, metallic NAs possess a simplified and miniaturized optical setup using collinear transmission measurement, denser integration, and smaller sensing footprint, enabling a high packing density for multiplex sensing on a microarray, well-controlled “hot spots” regions, and highly tunable resonance wavelength. − All of these characteristics make metallic NAs particularly suitable for lab-on-a-chip and point-of-care sensing in the field of bio-detection, medical diagnostics, environmental monitoring, and food safety. , …”

Beyond Capture: Circulating Tumor Cell Release and Single‐Cell Analysis

“…Unfortunately, shear stress affects viability and functions of these fragile CTCs, and it releases cells without specificity and selectivity. For CTCs captured with affinity‐based methods, proteolytic digestion of cell membrane antigens with trypsin or ethylene diamine tetraacetic acid (EDTA) is the initially adopted release method . However, as a destructive method, it degrades all cell surface proteins including important membrane protein markers, and harms the completeness of cell structure and the cell microenvironment .…”