The spread of cancer throughout the body is driven by circulating tumour cells (CTCs)1. These cells detach from the primary tumour and move from the blood stream to a new site of subsequent tumour growth. They also carry information about the primary tumour and have the potential to be valuable biomarkers for disease diagnosis and progression, and for the molecular characterization of certain biological properties of the tumour. However, the limited sensitivity and specificity of current methods to measure and study these cells in patient blood samples prevent the realization of their full clinical potential. The use of microfluidic devices is a promising method for isolating CTCs2, 3; however, the devices are reliant on three-dimensional structures, which limit further characterization and expansion of cells on the chip. Here we demonstrate an effective approach to isolate CTCs from blood samples of pancreatic, breast and lung cancer patients, by using functionalised graphene oxide nanosheets on a patterned gold surface. CTCs were captured with high sensitivity at low concentration of target cells (73% ± 32.4 at 3–5 cells/mL blood).
Circulating tumor cells (CTCs) are low frequency cells found in the bloodstream after having been shed from a primary tumor. These cells are research targets because of the information they may potentially provide about both an individual cancer as well as the mechanisms through which cancer spreads in the process of metastasis. Established technologies exist for CTC isolation, but the recent progress and future of this field lie in nanomaterials. In this review, we provide perspective into historical CTC capture as well as current research being conducted, emphasizing the significance of the materials being used to fabricate these devices. The modern investigation into CTCs initially featured techniques that have since been commercialized. A major innovation in the field was the development of a microfluidic capture device, first fabricated in silicon and followed up with glass and thermopolymer devices. We then specifically highlight the technologies incorporating magnetic nanoparticles, carbon nanotubes, nanowires, nanopillars, nanofibers, and nanoroughened surfaces, graphene oxide and their fabrication methods. The nanoscale provides a new set of tools that has the potential to overcome current limitations associated with CTC capture and analysis. We believe the current trajectory of the field is in the direction of nanomaterials, allowing the improvements necessary to further CTC research.
Vibration‐based Structural Health Monitoring (SHM) is one of the most popular solutions to assess the safety of civil infrastructure. SHM applications all begin with measuring the dynamic response of structures, but displacement measurement has been limited by the difficulty in requiring a fixed reference point, high cost, and/or low accuracy. Recently, researchers have conducted studies on vision‐based structural health monitoring, which provides noncontact and efficient measurement. However, these approaches have been limited to stationary cameras, which have the challenge of finding a location to deploy the cameras with appropriate line‐of‐sight, especially to monitor critical civil infrastructures such as bridges. The Unmanned Aerial System (UAS) can potentially overcome the limitation of finding optimal locations to deploy the camera, but existing vision‐based displacement measurement methods rely on the assumption that the camera is stationary. The displacements obtained by such methods will be a relative displacement of a structure to the camera motion, not an absolute displacement. Therefore, this article presents a framework to achieve absolute displacement of a structure from a video taken from an UAS using the following phased approach. First, a target‐free method is implemented to extract the relative structural displacement from the video. Next, the 6 degree‐of‐freedom camera motion (three translations and three rotations) is estimated by tracking the background feature points. Finally, the absolute structural displacement is recovered by combining the relative structural displacement and the camera motion. The performance of the proposed system has been validated in the laboratory using a commercial UAS. Displacement of a pinned‐connected railroad truss bridge in Rockford, IL subjected to revenue‐service traffic loading was reproduced on a hydraulic simulator, while the UAS was flown from a distance of 4.6 m (simulating the track clearance required by the Federal Railroad Administration), resulting in estimated displacements with an RMS error of 2.14 mm.
We present "Labyrinth," a label-free microfluidic device to isolate circulating tumor cells (CTCs) using the combination of long loops and sharp corners to focus both CTCs and white blood cells (WBCs) at a high throughput of 2.5 mL/min. The high yield (>90%) and purity (600 WBCs/mL) of Labyrinth enabled us to profile gene expression in CTCs. As proof of principle, we used previously established cancer stem cell gene signatures to profile single cells isolated from the blood of breast cancer patients. We observed heterogeneous subpopulations of CTCs expressing genes for stem cells, epithelial cells, mesenchymal cells, and cells transitioning between epithelial and mesenchymal. Labyrinth offers a cell-surface marker-independent single-cell isolation platform to study heterogeneous CTC subpopulations.
DNA methylation patterns are associated with the development and prognosis of cancer. The aim of this study was to identify novel methylation markers for the prediction of patient outcomes using microarray analysis of DNA methylation and RNA expression patterns in samples from long-term follow-up patients with nonmuscle invasive bladder cancer (NMIBC). A total of 187 human bladder specimens were used for microarray array or pyrosequencing (PSQ) analyses: 6 normal controls (NC) and 181 NMIBC. Tumor-specific hypermethylated genes were selected from a data set comprising 24 matched microarray-based DNA methylation and gene expression profiles (6 controls and 18 NMIBC), and their clinical relevance was verified by quantitative PSQ analysis. The methylation status of Homeobox A9 (HOXA9), ISL LIM homeobox 1 (ISL1) and Aldehyde dehydrogenase 1 family, member A3 (ALDH1A3) was significantly associated with decreased gene expression levels and aggressive clinicopathological characteristics. Multivariate regression analyses showed that hypermethylation of these genes was an independent predictor of disease recurrence (HOXA9, ISL1 and ALDH1A3, either alone or in combination) and progression (ISL1 and ALDH1A3, either alone or in combination) (each p < 0.05). The results of this study suggest that these novel methylation markers are independent prognostic indicators in NMIBC patients, which may facilitate the assessment of disease recurrence and progression in NMIBC patients and inform clinical decision making regarding treatment.
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