Biomolecular Surfaces for the Capture and Reprogramming of Circulating Tumor Cells

Circulating Tumor Cells(CTC)have the potential to be used clinically as a diagnostic tool and a treatment tool in the field of oncology.As a diagnostic tool,CTC may be used to indicate the presence of a tumor before it is large enough to cause noticeable symptoms.As a treatment tool,CTC isolated from patients may be used to test the efficacy of chemotherapy options to personalize patient treatment.One way for tumors to spread is through metastasis via the circulatory system.CTC are able to exploit the natural leukocyte recruitment process that is initially mediated by rolling on transient selectin bonds.Our capture devices take advantage of this naturally occurring recruitment step to isolate CTC from whole blood by flowing samples through selectin and antibody-coated microtubes.Whole blood was spiked with a known concentration of labeled cancer cells and then perfused through pre-coated microtubes.Microtubes were then rinsed to remove unbound cells and the number of labeled cells captured on the lumen was assessed.CTC were successfully captured from whole blood at a clinically relevant level on the order of 10 cells per mL.Combination tubes with selectin and antibody coated surface exhibited higher capture rate than tubes coated with selectin alone or antibody alone.Additionally,CTC capture was demonstrated with the KG 1 a hematopoietic cell line and the DU 145 epithelial cell line.Thus,the in vivo process of selectin-mediated CTC recruitment to distant vessel walls can be used in vitro to target CTC to a tube lumen.The biomolecular coatings can also be used to capture CTC of hematopoietic and epithelial tumor origin and is demonstrated to sensitivities down to the order of 10 CTC per mL. In a related study aimed at reducing the blood borne metastatic cancer load,we have shown that cells captured to a surface can be neutralized by a receptor-mediated biochemical signal.In the proposed method we have shown that using a combined selectin and TRAIL(TNF Related Apoptosis Inducing Ligand or Apo 2L)functionalized surface we are able to kill about 30% of the captured cells in a short duration of one hour whereas it took about 4 hours to kill the same proportion of cells without flow on a similarly functionalized surface.Here we have taken the approach a step further by showing that with very small doses of chemotherapeutic agents like bortezomib,we can increase the kill rate of CTC,thus allowing the device to function in scenarios where the patient is undergoing treatment.We show here that,with leukemic cells treated with bortezomib we are able to kill about 41% of the captured cells.

Cell biomechanics and its applications in human disease diagnosis

Certain diseases are known to cause changes in the physical and biomechanical properties of cells.These include cancer,malaria,and sickle cell anemia among others.Typically,such physical property changes can result in several fold increases or decreases in cell stiffness,which are significant and can result in severe pathology and eventual catastrophic breakdown of the bodily functions.While there are developed biochemical and biological assays to detect the onset or presence of diseases,there is always a need to develop more rapid,precise,and sensitive methods to detect and diagnose diseases.Biomechanical property changes can play a significant role in this regard.As such,research into disease biomechanics can not only give us an in-depth knowledge of the mechanisms underlying disease progression,but can also serve as a powerful tool for detection and diagnosis.This article provides some insights into opportunities for how significant changes in cellular mechanical properties during onset or progression of a disease can be utilized as useful means for detection and diagnosis.We will also showcase several technologies that have already been developed to perform such detection and diagnosis.

Green Synthesized Liquid-like Dynamic Polymer Chains with Decreased Nonspecific Adhesivity for High-Purity Capture of Circulating Tumor Cells

The capture of circulating tumor cells(CTCs)is of great significance in reducing cancer mortality and complications.However,the nonspecific binding of proteins and white blood cells(WBCs)weakens the targeting capabilities of the capture surfaces,which critically hampers the efficiency and purity of the captured CTCs.Herein,we propose a liquid-like interface design strategy that consists of liquid-like polymer chains and anti-EpCAM modification processes for high-purity and high-efficiency capture of CTCs.The dynamic flexible feature of the liquid-like chains endows the modified surfaces with excellent antiadhesion property for proteins and blood cells.The liquid-like surfaces can capture the target CTCs and show high cell viability due to the environmentfriendly surface modification processes.When liquid-like surface designs were introduced in the deterministic lateral displacement(DLD)-patterned microfluidic chip,the nonspecific adhesion rate of WBCs was reduced by more than fivefold compared to that in the DLD chip without liquid-like interface design,while maintaining comparable capture efficiency.Overall,this strategy provides a novel perspective on surface design for achieving high purity and efficient capture of CTCs.

Folic Acid Modified Electrospun Poly(vinyl alcohol)/Polyethyleneimine Nanofibers for Cancer Cell Capture Applications

Capture and detection of metastatic cancer cells are crucial for diagnosis and treatment of malignant neoplasm. Here, we report the use of folic acid （FA） modified electrospun poly（vinyl alcohol） （PVA）/polyethyleneimine （PEI） nanofibers for cancer cell capture applications. Electrospun PVA/PEI nanofibers crosslinked by glutaraldehyde vapor were modified with FA via a poly（ethylene glycol） （PEG） spacer, followed by acetylation of the fiber surface PEI amines. The formed FA-modified nanofibers were well characterized. The morphology of the electrospun PVA/PEI nanofibers is smooth and uniform despite the surface modification. In addition, the FA-modified nanofibers display good hemocompatibility as confirmed by hemolysis assay. Importantly, the developed FA-modified nanofibers are able to specifically capture cancer cells overexpressing FA receptors, which were validated by quantitative cell counting assay and qualitative confocal microscopy analysis. The developed FA-modified PVA/PEI nanofibers may be used for capturing circulating tumor cells for cancer diagnosis applications.

Thermo-responsive imprinted hydrogel with switchable sialic acid recognition for selective cancer cell isolation from blood

In this work,a sialic acid(SA)-imprinted thermo-responsive hydrogel layer was prepared for selective capture and release of cancer cells.The SA-imprinting process was performed at 37℃ using thermo-responsive functional monomer,thus generating switchable SA-recognition sites with potent SA binding at 37℃and weak binding at a lower temperature(e.g.,25℃).Since SA is often overexpressed at the glycan terminals of cell membrane proteins or lipids,the SA-imprinted hydrogel layer could be used for selective cancer cell recognition.Our results confirmed that the hydrogel layer could efficiently capture cancer cells from not only the culture medium but also the real blood samples.In addition,the captured cells could be non-invasively released by lowing the temperature.Considering the non-invasive processing mode,considerable capture efficiency,good cell selectivity,as well as the more stable and durable SA-imprinted sites compared to natural antibodies or receptors,this thermo-responsive hydrogel layer could be used as a promising and general platform for cell-based cancer diagnosis.