Hierarchical Spiky Microstraws‐Integrated Microfluidic Device for Efficient Capture and In Situ Manipulation of Cancer Cells

Abstract

Techniques for capturing circulating tumor cells (CTCs) play an important role in cancer diagnosis. Recently, various 3D micro/nanostructures have been applied for effective CTC detection, yet in situ manipulation of the captured cancer cells on micro/nano‐structural substrates is rarely achieved. In this work, a hierarchical spiky microstraw array (HS‐MSA)‐integrated microfluidic device is demonstrated that possessed dual functions of cancer cell capture and in situ chemical manipulations of the captured cells. The 3D micro/nanostructure of HS‐MSA could capture cancer cells with high efficiency (≈84%) and strong specificity. Based on the HS‐MSA‐integrated microfluidic device, extracellular drug delivery to the captured cancer cells is achieved in situ with excellent spatial, dose, and temporal controls. In addition, a drug‐screening assay on the captured cancer cells is implemented to investigate the cell apoptosis behavior under the microstraw‐mediated delivery of staurosporine (STS). This microfluidic system not only presents tremendous potential for CTCs detection technology, but also opens up new opportunities for high‐throughput drug screening on cancer cells and understanding the cellular activity.

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…Intracellular delivery experiments with hollow nanostraws provide further evidence that spontaneous penetration is rare . However, penetration can be enhanced via electroporation (Figure G), optoporation (Figure H), or by coating nanostraws with strongly cell‐adhering coatings . Bioelectronic experiments show that nanoelectrodes only measure intracellular potentials after poration techniques have been applied, and rapidly return to measuring extracellular potentials in the absence of further external stimulus, again highlighting the need for an external force to disrupt the membrane.…”

“…He et al fabricated hollow microstraws with nanoscale spiked coatings and microfluidics to create a combined capture and delivery system . Their microstraw platform is conceptually similar to nanostraws (albeit with a relatively low aspect ratio of 1:1.5), and the nanoscale spiked coating an interesting variant on this concept.…”

“…While cell‐capture systems based on high‐aspect‐ratio nanostructures are relatively unexplored, the recent reports of combined capture–delivery systems, plus the advent of interesting photo‐active capture chemistries, suggest this is a growing area of research.…”

High‐Performance Flexible Bioelectrocatalysis Bioassay System Based on a Triphase Interface

“…Sample dilution (30–50 times) is generally performed to minimize the interference concentration; however, this strategy correspondingly minimizes the target concentration and is not practical due to the low analyte level in sweat and interstitial fluids. In our triphase bioassay system, the constant interface oxygen level enables the application of H 2 O 2 cathodic reaction in bioassay development . Cathodic measurement of enzymatic product H 2 O 2 naturally avoids interferences arising from oxidizable endogenous/exogenous species in body fluid during glucose detection.…”

“…Flexible devices have attracted extensive research interest in the fields of physiological monitoring, intelligent display, energy collection, and storage . Flexible biosensors based on individual's physiological biomarkers have recently been fabricated that are able to provide insight into the user's health state at a molecular level as well as diabetic monitoring . In the presence of O 2 , almost all oxidases will catalyze (oxidize) their substrates (analytes) producing H 2 O 2 , the cathodic measurement of which is an ideal approach for analyte level quantification .…”