Full Surface Embedding of Gold Clusters on Silicon Nanowires for Efficient Capture and Photothermal Therapy of Circulating Tumor Cells

Abstract

We report on rapid thermal chemical vapor deposition growth of silicon nanowires (Si NWs) that contain a high density of gold nanoclusters (Au NCs) with a uniform coverage over the entire length of the nanowire sidewalls. The Au NC-coated Si NWs with an antibody-coated surface obtain the unique capability to capture breast cancer cells at twice the highest efficiency currently achievable (~88% at 40 min cell incubation time) from a nanostructured substrate. We also found that irradiation of breast cancer cells captured on Au NC-coated Si NWs with a near-infrared light resulted in a high mortality rate of these cancer cells, raising a fine prospect for simultaneous capture and plasmonic photothermal therapy for circulating tumor cells.

Effects of nanopillar array diameter and spacing on cancer cell capture and cell behaviors

“…Hemocytometer was used to count cells and according dilution was subsequently pursued to reach a cell concentration around 10 5 /mL. 19 The cell concentration was selected also for ensuring the yield of a large result data pool to reach a reliable conclusion.…”

“…In previous studies, nanostructures with size ranging from 30 to 1150 nm have been employed for CTCs isolation, and high efficiency was reported in all cases. For instance, 88% of cancer cells were captured onto antibody immobilized silicon nanowires (SiNWs) with diameter of 50–160 nm; 19 high isolation efficiency up to 95% was reported on antibody grafted silicon nanopillars (NPs) with diameter in the range of 100–200 nm; 20 cancer cell isolation efficiency on antibody grafted spherical particles with diameter of 232 nm was 4–5 times higher than on a flat surface. 21 Nanostructured surfaces with halloysite nanotubes was also demonstrated to enhance the CTC recruitment with a three-fold increase for MCF7 cells, while nonspecific leukocytes adhesion was prevented.…”

Silicon Nanostructures for Cancer Diagnosis and Therapy

“…Meanwhile, compared with free AuNPs, Shen demonstrated that pSi/HAuNSs generated much more heat to efficiently destroy breast cancer cells in vitro and xenografted tumor in vivo. In 2012, Su et al and Park et al further described the use of the AuNPs and gold nanoclusters (AuNCs)-decorated SiNWs as photothermal agents to destroy cancer cells under NIR light irradiation (808 nm) [25,26]. KB cancer cells treated with PEG-AuNPs@ SiNWs (150 μg/ml) were all destroyed through 3-min exposure of 808 nm NIR laser at the power density of 2 W/cm 2 , and all of the MCF-7 cells captured by the AuNCs-SiNWs were killed after an NIR light irradia- Reproduced with permission from [19,24].…”

“…First, we describe typical kinds of silicon nanomaterialbased biosensors (e.g., field-effect transistors [FET] and surface-enhanced Raman scattering [SERS] sensors), enabling ultrahighly sensitive detection of cancer markers (e.g., proteins, tumor-suppressor genes and telomerase activity, among others) [20][21][22][23]. Second, we introduce the latest progress in the development of silicon nanomaterial-based nanoagents for cancer chemotherapy and phototherapy applications in vitro and in vivo [13,19,[24][25][26][27][28][29][30][31]. Finally, we discuss the challenges and opportunities in this promising field.…”

Silicon-Based Nanoagents for Cancer Therapy

“…5.10). Meanwhile, Park et al reported gold nanoclusters (AuNCs)-coated SiNWs as a substrate for concurrent capture and phototherapy of tumor cells [68]. In their work, to capture tumor cells with high specificity, specific antibody was first conjugated with the AuNC-coated SiNWs.…”