Release Of Circulating Tumor Cells Research Articles

Investigating the influence of Preoperative Trans Arterial Embolization (TAE) and Predictive Potential of Circulating Tumor Cells (CTCs) in prognosis of Hepatocellular Carcinoma

IntroductionCirculating Tumor Cells are a promising biomarker in many malignancies. CTC dissemination during the operative procedure can lead to disease recurrence. The effect of preoperative Transarterial Embolization on the release of CTCs and miRNA panels and oncological outcomes in large hepatocellular carcinomas has been evaluated. Materials and MethodsThe study included non-metastatic HCC >5cm in size, that were completely resected after TAE (n=10). Blood was collected pre-TAE, post-TAE, postoperative (day 2,30 and 180) and analyzed for the presence of CTC and miRNA (miR885-5p, miR22-3p, miR 642b-5p). The samples were subjected to CTC enrichment, isolation and staining using the markers CD45, EpCAM and Cytokeratin (CK). The data was analyzed using Gene Expression Suite software. ResultsThe CTC enumeration resulted in three groups: Group 1- CTC present at both Pre TAE and postoperative day 30 (n=4), Group 2- CTC present Pre-TAE and clearing at postoperative day 30 (n=2), Group 3- No CTC detected at any stages (n=3). Group 2 patients had better survival as compared to the other groups. Downregulation of miRNA 22-3p also had favourable prognostic implications. ConclusionWhile preoperative TAE does not seem to impact CTC shedding, CTC clearance may prove to be a valuable biomarker in prognosticating HCC. A larger study to evaluate the significance of CTCs as a prognostic marker is warranted to further evaluate these findings.

Precise Capture and Dynamic Release of Circulating Liver Cancer Cells with Dual-Histidine-Based Cell Imprinted Hydrogels.

Circulating tumor cells (CTCs) detection presents significant advantages in diagnosing liver cancer due to its noninvasiveness, real-time monitoring, and dynamic tracking. However, the clinical application of CTCs-based diagnosis is largely limited by the challenges of capturing low-abundance CTCs within a complex blood environment while ensuring them alive. Here, an ultrastrong ligand, l-histidine-l-histidine (HH), specifically targeting sialylated glycans on the surface of CTCs, is designed. Furthermore, HH is integrated into a cell-imprinted polymer, constructing a hydrogel with precise CTCs imprinting, high elasticity, satisfactory blood compatibility, and robust anti-interference capacities. These features endow the hydrogel with excellent capture efficiency (>95%) for CTCs in peripheral blood, as well as the ability to release CTCs controllably and alive. Clinical tests substantiate the accurate differentiation between liver cancer, cirrhosis, and healthy groups using this method. The remarkable diagnostic accuracy (94%), lossless release of CTCs, material reversibility, and cost-effectiveness ($6.68 per sample) make the HH-based hydrogel a potentially revolutionary technology for liver cancer diagnosis and single-cell analysis.

Controllable Assembly of a Quantum Dot-Based Aptasensor Guided by CRISPR/Cas12a for Direct Measurement of Circulating Tumor Cells in Human Blood.

Accurate and sensitive analysis of circulating tumor cells (CTCs) in human blood provides a non-invasive approach for the evaluation of cancer metastasis and early cancer diagnosis. Herein, we demonstrate the controllable assembly of a quantum dot (QD)-based aptasensor guided by CRISPR/Cas12a for direct measurement of CTCs in human blood. We introduce a magnetic bead@activator/recognizer duplex core-shell structure to construct a multifunctional platform for the capture and direct detection of CTCs in human blood, without the need for additional CTC release and re-identification steps. Notably, the introduction of magnetic separation ensures that only a target-induced free activator can initiate the downstream catalysis, efficiently avoiding the undesired catalysis triggered by inappropriate recognition of the activator/recognizer duplex structure by crRNAs. This aptasensor achieves high CTC-capture efficiency (82.72%) and sensitive detection of CTCs with a limit of detection of 2 cells mL-1 in human blood, holding great promise for the liquid biopsy of cancers.

Glowing Octopus-Inspired Nanomachine: A Versatile Aptasensor for Efficient Capture, Imaging, Separation, and NIR-Triggered Release of Cancer Cells.

The separation and analysis of circulating tumor cells (CTCs) in liquid biopsy significantly facilitated clinical cancer diagnosis and personalized therapy. However, current methods face challenges in simultaneous efficient capturing, separation, and imaging of CTCs, and most of the devices cannot be reused/regenerated. We present here an innovative glowing octopus-inspired nanomachine (GOIN), capable of capturing, imaging, separating, and controlling the release of cancer cells from whole blood and normal cells. The GOIN comprises an aptamer-decorated magnetic fluorescent covalent organic framework (COF), which exhibits a strong affinity for nucleolin-overexpressed cancer cells through a multivalent binding effect. The captured cancer cells can be directly imaged using the intrinsic stable fluorescence of the COF layer in the GOIN. Employing magnet and NIR laser assistance enables easy separation and mild photothermal release of CTCs from the normal cells and the nanomachine without compromising cell viability. Moreover, the GOIN demonstrates a reusing capability, as the NIR-triggered CTC release is mild and nondestructive, allowing the GOIN to be reused at least three times.

Radiofrequency ablation induces tumor cell dissemination in a mouse model of hepatocellular carcinoma

BackgroundWe tested the hypothesis that radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) promotes tumor cell release and explored a method for reducing these effects.MethodsA green fluorescent protein-transfected orthotopic HCC model was established in 99 nude mice. In vivo flow cytometry was used to monitor circulating tumor cell (CTC) dynamics. Pulmonary fluorescence imaging and pathology were performed to investigate lung metastases. First, the kinetics of CTCs during the periablation period and the survival rate of CTCs released during RFA were investigated. Next, mice were allocated to controls, sham ablation, or RFA with/without hepatic vessel blocking (ligation of the portal triads) for evaluating the postablation CTC level, lung metastases, and survival over time. Moreover, the kinetics of CTCs, lung metastases, and mice survival were evaluated for RFA with/without ethanol injection. Pathological changes in tumors and surrounding parenchyma after ethanol injection were noted. Statistical analysis included t-test, ANOVA, and Kaplan-Meier survival curves.ResultsCTC counts were 12.3-fold increased during RFA, and 73.7% of RFA-induced CTCs were viable. Pre-RFA hepatic vessel blocking prevented the increase of peripheral CTCs, reduced the number of lung metastases, and prolonged survival (all p ≤ 0.05). Similarly, pre-RFA ethanol injection remarkably decreased CTC release during RFA and further decreased lung metastases with extended survival (all p ≤ 0.05). Histopathology revealed thrombus formation in blood vessels after ethanol injection, which may clog tumor cell dissemination during RFA.ConclusionRFA induces viable tumor cell dissemination, and pre-RFA ethanol injection may provide a prophylactic strategy to reduce this underestimated effect.Relevance statementRFA for HCC promotes viable tumor cell release during ablation, while ethanol injection can prevent RFA induced tumor cell release.Key points• RFA induced the release of viable tumor cells during the ablation procedure in an animal model.• Hepatic vessel blocking can suppress tumor cells dissemination during RFA.• Ethanol injection can prevent RFA-induced tumor cell release, presumably because of the formation of thrombosis.Graphical

Effect of various hepatectomy procedures on circulating tumor cells in postoperative patients: a case-matched comparative study.

The objective of this study is to elucidate the prevalence of systemic circulating tumor cells (CTCs) prior to and following resection of hepatocellular carcinoma (HCC), and to compare the disparities in postoperative CTCs in terms of quantity and classifications between the open liver resection (OPEN) and laparoscopic liver resection (LAP) cohorts. From September 2015 to May 2022, 32 consecutive HCC patients who underwent laparoscopic liver resection at Southwest Hospital were retrospectively enrolled in this study. The clinicopathological data were retrieved from a prospectively collected computer database. Patients in the OPEN group matched at a 1:1 ratio with patients who underwent open liver resection during the study period on age, gender, tumor size, number of tumors, tumor location, hepatitis B surface antigen (HBsAg) positivity, alpha-fetoprotein (AFP) level, TNM and Child-Pugh staging from the database of patients to form the control group. The Can-Patrol CTC enrichment technique was used to enrich and classify CTCS based on epithelial-mesenchymal transformation phenotypes. The endpoint was disease-free survival (DFS), and the Kaplan-Meier method and multiple Cox proportional risk model were used to analyze the influence of clinicopathological factors such as total CTCs and CTC phenotype on prognosis. The mean age of the 64 patients with primary liver cancer was 52.92 years (23-71), and 89.1% were male. The postoperative CTC clearance rate was more significant in the OPEN group. The total residual CTC and phenotypic CTC of the LAP group were significantly higher than those of the OPEN group (p = 0.017, 0.012, 0.049, and 0.030, respectively), which may increase the possibility of metastasis (p = 0.042). In Kaplan-Meier analysis, DFS was associated with several clinicopathological risk factors, including Barcelona Clinical Liver Cancer (BCLC) stage, tumor size, and vascular invasion. Of these analyses, BCLC Stage [p = 0.043, HR (95% CI) =2.03(1.022-4.034)], AFP [p = 0.007, HR (95% CI) =1.947 (1.238-3.062)], the number of positive CTCs [p = 0.004, HR (95% CI) =9.607 (2.085-44.269)] and vascular invasion [p = 0.046, HR (95% CI) =0.475 (0.22-1.023)] were significantly associated with DFS. In comparison to conventional OPEN technology, LAP technology has the capacity to augment the quantity of epithelial, mixed, and mesenchymal circulating tumor cells (CTCs). Following the surgical procedure, there was a notable increase in the total CTCs, epithelial CTCs, and mixed CTCs within the LAP group, indicating a potential drawback of LAP in facilitating the release of CTCs.

A microfluidic device for enhanced capture and high activity release of heterogeneous CTCs from whole blood

Circulating tumor cells (CTCs) are tumor cells that spontaneously detach from the primary focus, and early detection and characterization of CTCs is vital for cancer diagnosis and appropriate treatment. Current methods commonly use EpCAM to capture CTCs, but this results in a loss of information on other CTC subsets (EpCAM-negative cells) due to the heterogeneity of CTCs. Here, we report a novel microfluidic device that integrates the capture and release of heterogeneous CTCs directly from whole blood. A spiral chip was designed for the separation of differently sized cells, and larger CTCs were effectively separated from smaller blood cells with a 98% recovery rate. CD146-containing magnetic beads were used to complement the EpCAM-based CTC capture methods, and the capture efficiency of Fe3O4@Gelatin@CD146/EpCAM increased by 20% over Fe3O4@Gelatin@EpCAM. Finally, MMP-9 was employed to release CTCs with high efficiency and less damage by degrading gelatins on the surface of Fe3O4. The established method was successfully applied to CTC capture and release in a simulated patient's whole blood. The developed method achieved enhanced capture and high activity release of heterogeneous CTCs with less interference by blood cells, which contributes to the early detection and clinical downstream analysis of CTCs.

An integrated and renewable interface for capture, release and analysis of circulating tumor cells

Circulating tumor cells (CTCs) have now emerged as a type of promising circulating biomarkers in liquid biopsy and can predict the occurrence and development of cancers. In this work, an integrated and renewable interface is fabricated for the capture, release and quantitative analysis of CTCs. As designed, folate receptor-positive CTCs are captured by folic acid-modified DNA probes at the interface through the receptor-ligand interaction, and are efficiently released from the interface with the aid of bleomycin-ferrous complex-regulated cleavage. Taking MCF-7 cells as the model, the functional interface demonstrates high efficiency to selectively capture the folate receptor-positive tumor cells, and the bleomycin-ferrous complex-regulated cleavage not only easily releases the captured cells with well-maintained viability and proliferation ability, but also releases silver nanoparticles that are labeled at the cell surface for highly sensitive quantification by adopting electrochemical techniques with a detection limit of 6 cells/mL. At the meanwhile, the interface is proved to be regenerated through a simple cleavage-hybridization event and reused with high stability. Therefore, our work may provide a new idea for the collection and downstream researches of circulating tumor cells in the future.

Tumor Microenvironment-Inspired Glutathione-Responsive Three-Dimensional Fibrous Network for Efficient Trapping and Gentle Release of Circulating Tumor Cells

Detection of circulating tumor cells (CTCs) is important for early cancer diagnosis, prediction of postoperative recurrence, and individualized treatment. However, it is still challenging to achieve efficient capture and gentle release of CTCs from the complex peripheral blood due to their rarity and fragility. Herein, inspired by the three-dimensional (3D) network structure and high glutathione (GSH) level of the tumor microenvironment (TME), a 3D stereo (3D-G@FTP) fibrous network is developed by combining the liquid-assisted electrospinning method, gas foaming technique, and metal-polyphenol coordination interactions to achieve efficient trapping and gentle release of CTCs. Compared with the traditional 2D@FTP fibrous scaffold, the 3D-G@FTP fibrous network could achieve higher capture efficiency (90.4% vs 78.5%) toward cancer cells in a shorter time (30 min vs 90 min). This platform showed superior capture performance toward heterogeneous cancer cells (HepG2, HCT116, HeLa, and A549) in an epithelial cell adhesion molecule (EpCAM)-independent manner. In addition, the captured cells with high cell viability (>90.0%) could be gently released under biologically friendly GSH stimulus. More importantly, the 3D-G@FTP fibrous network could sensitively detect 4-19 CTCs from six kinds of cancer patients' blood samples. We expect this TME-inspired 3D stereo fibrous network integrating efficient trapping, broad-spectrum recognition, and gentle release will promote the development of biomimetic devices for rare cell analysis.

Conductive Nanofibers-Enhanced Microfluidic Device for the Efficient Capture and Electrical Stimulation-Triggered Rapid Release of Circulating Tumor Cells

The effective detection and release of circulating tumor cells (CTCs) are of great significance for cancer diagnosis and monitoring. The microfluidic technique has proved to be a promising method for CTCs isolation and subsequent analysis. However, complex micro-geometries or nanostructures were often constructed and functionalized to improve the capture efficiency, which limited the scale-up for high-throughput production and larger-scale clinical applications. Thus, we designed a simple conductive nanofiber chip (CNF-Chip)-embedded microfluidic device with a herringbone microchannel to achieve the efficient and specific capture and electrical stimulation-triggered rapid release of CTCs. Here, the most used epithelial cell adhesion molecule (EpCAM) was selected as the representative biomarker, and the EpCAM-positive cancer cells were mainly studied. Under the effects of the nanointerface formed by the nanofibers with a rough surface and the herringbone-based high-throughput microfluidic mixing, the local topographic interaction between target cells and nanofibrous substrate in the microfluidic was synergistically enhanced, and the capture efficiency for CTCs was further improved (more than 85%). After capture, the sensitive and rapid release of CTCs (release efficiency above 97%) could be conveniently achieved through the cleavage of the gold-sulfur bond by applying a low voltage (-1.2 V). The device was successfully used for the effective isolation of CTCs in clinical blood samples from cancer patients, indicating the great potential of this CNF-Chip-embedded microfluidic device in clinical applications.

Abstract 5602: Markers of hypoxic cells: Testing a pre-clinical detection assay

Abstract The proposed project aims to test the applicability of a novel set of patented organic compounds as markers of hypoxic circulating tumor cells (H-CTC) with potential pre-clinical relevance. Circulating tumor cells (CTC) are individual cells or clusters that can move from tumors to circulation invading other tissues. Often cells in the tumor need to adapt to low oxygen levels, generating a population of cells known as hypoxic cells that can survive low oxygen levels. These hypoxic cells can produce more cell junction proteins, augmenting connections between cells causing them to break away in clusters rather than individually. Clustered CTCs are much more efficient at metastasis formation. Release of CTC can also be stimulated by cancer treatments such as radiation and chemotherapy. To date, our research has generated in-vitro studies with a set of 3-nitrobenzazolo[3,2- a]quinolinium chloride salts (NBQS) demonstrating its capacity as markers of hypoxic human cancer cells in vitro. Comparison with the control Pimonidazole demonstrated the advantages of novel NBQ-TOM compounds as hypoxic marker. We here, aim to test the applicability of NBQS to identify hypoxic cells among circulating tumor cells (H-CTC). To date limited commercially CTC detection methods are available. Our application can be described as pre-clinical detection technology of hypoxic cancer cells serving also in cancer management. To determine the capacity of novel compound, NBQ-345 TOM as hypoxic fluorescent marker, colon tumor cells (COLO 205) are culture under hypoxic and aerobic environment and treated with NBQ-345TOM (25uM) for 24 hours. After treatment fluorescence is measured with an OPTIMA BMG Fluorimeter. Fluorescence emission results demonstrated significant formation of the NBQ-234 TOM fluorescent metabolite on hypoxic tumor cells in contrast to cells treated under aerobic environment. Also, fluorescence microscopy analysis of colon cancer cells treated for 24 hours with NBQ-345 TOM at hypoxic and aerobic conditions confirmed the stronger fluorescence generation at hypoxic conditions in contrast to cells at aerobic conditions. Citation Format: Beatriz Zayas, Karoline Rios, Luis Ortiz, Osvaldo Cox. Markers of hypoxic cells: Testing a pre-clinical detection assay. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5602.

Nondestructive separation/enrichment and rolling circle amplification-powered sensitive SERS enumeration of circulating tumor cells via aptamer recognition

Nondestructive separation/enrichment and reliable detection of extremely rare circulating tumor cells (CTCs) in peripheral blood are of considerable importance in tumor precision diagnosis and treatment, yet this remains a big challenge. Herein, a novel strategy for nondestructive separation/enrichment and ultra-sensitive surface-enhanced Raman scattering (SERS)-based enumeration of CTCs is proposed via aptamer recognition and rolling circle amplification (RCA). In this work the magnetic beads modified with "Aptamer (Apt)-Primer" (AP) probes were utilized to specifically capture CTCs, and then after magnetic separation/enrichment, the RCA-powered SERS counting and benzonase nuclease cleavage-assisted nondestructive release of CTCs were realized, respectively. The AP was assembled by hybridizing the EpCAM-specific aptamer with a primer, and the optimal AP contains 4 mismatched bases. The RCA enhanced SERS signal nearly 4.5-fold, and the SERS strategy has good specificity, uniformity and reproducibility. The proposed SERS detection possesses a good linear relationship with the concentration of MCF-7 cells spiked in PBS with the limit of detection (LOD) of 2 cells/mL, which shows good potential practicality for detecting CTCs in blood with recoveries ranging from 100.56% to 116.78%. Besides, the released CTCs remained good cellular activity with the normal proliferation after re-culture for 48 h and normal growth for at least three generations. The proposed strategy of nondestructive separation/enrichment and SERS-based sensitive enumeration is promising for reliable analysis of EpCAM-positive CTCs in blood, which is expected to provide a powerful tool for analysis of extremely rare circulating tumor cells in complex peripheral blood for liquid biopsy.

Capture and release of circulating tumor cells stimulated by pH and NIR irradiation of magnetic Fe3O4@ZIF-8 nanoparticles

Detecting and analyzing circulating tumor cells(CTCs) is significant for early diagnosis, management, and personalized treatment of tumors. Herein, a smart magnetic aptamer modified Fe3O4@ZIF-8 core/shell structured nanoparticle (NPs) was successfully constructed using for capture and simultaneous pH- and NIR-irradiation responsive release of CTCs. Taking MCF-7 as model CTCs, it could be captured ca. 60 % in low-concentration artificial blood by aptamer (SYL3C) on the surface of Fe3O4@ZIF-8 NPs. After magnetic separation, the ZIF-8 shell in aptamer-modified Fe3O4@ZIF-8 NPs carrying captured CTCs would disintegrate within 20 min under the synergistic effect of an acidic environment (pH=6.0) and NIR irradiation leading to the release of CTCs with high cell viability, which was benefited for the subsequent culture and analysis. This magnetic and core/shell structured device integrated high-efficiency capture, quick isolation and perfect release into one system, which showed great potentials for the detection of CTCs in the clinic.

Capture and Release of Cancer Cells Through Smart Bioelectronics.

Noninvasive collection of target cells such as circulating tumor cells (CTCs) is crucial for biology and medicine research. Conventional methods of cell collection are often complex, requiring either size-dependent sorting or invasive enzymatic reactions. Here, we show the development of a functional polymer film, which combines the thermoresponsive poly(N-isopropylacrylamide) and the conducting poly(3,4-ethylenedioxythiopene)/poly(styrene sulfonate), and its use for the capture and release of CTCs. When coated onto microfabricated gold electrodes, the proposed polymer films are capable of noninvasively capturing and controllably releasing cells while, at the same time, monitoring these processes with conventional electrical measurements.

Improving performance of cell imprinted PDMS by integrating boronate affinity and local post-imprinting modification for selective capture of circulating tumor cells from cancer patients

Efficient capture of circulating tumor cells (CTCs) from cancer patients is an important technique that may promote early diagnosis and prognosis monitoring of cancer. However, the existing systems have certain disadvantages, such as poor selectivity, low capture efficiency, consumption of antibodies, and difficulty in release of CTCs for downstream analysis. Herein, we fabricated an innovative PEGylated boronate affinity cell imprinted polydimethylsiloxane (PBACIP) for highly efficient capture of CTCs from cancer patients. The antibody-free PBACIP possessed hierarchical structure of imprinted cavities, which were inlaid with boronic acid modified SiO2 nanoparticles (SiO2@BA), so it could specifically capture target CTCs from biological samples due to the synergistic effect of boronate affinity and cell imprinting. Furthermore, PEGylation was accurately completed in the non-imprinted region by the template cells occupying the imprinted cavity, which not only retained the microstructure of original imprinted cavities, but also endowed PBACIP with hydrophilicity. The artificial PBACIP could efficiently capture human breast-cancer cells from biological sample. When 5 to 500 SKBR3 cells were spiked in 1 mL mice lysed blood, the capture efficiency reached 86.7 ± 11.5% to 96.2 ± 2.3%. Most importantly, the PBACIP was successfully used to capture CTCs from blood of breast cancer patients, and the captured CTCs were released for subsequent gene mutation analysis. The PBACIP can efficiently capture and release CTCs for downstream analysis, which provides a universal strategy toward individualized anti-tumor comprehensive treatments and has great potential in the future cell-based clinical applications.

Facile Preparation of Three-Dimensional Wafer with Interconnected Porous Structure for High-Performance Capture and Nondestructive Release of Circulating Tumor Cells.

Efficient isolation and downstream bioinformation analysis of circulating tumor cells (CTCs) in whole blood contribute to the early diagnosis of cancer and investigation of cancer metastasis. However, the separation and release of CTCs remain a great challenge due to the extreme rarity of CTCs and severe interference from other cells in complex clinical samples. Herein, we developed a low-cost and easy-to-fabricate aptamer-functionalized wafer with a three-dimensional (3D) interconnected porous structure by grafting polydopamine (PDA), poly(ethylene glycol) (PEG), and aptamer in sequence (Ni@PDA-PEG-Apt) for the capture and release of CTCs. The Ni@PDA-PEG-Apt wafer integrated the features of Ni foam with a 3D interconnected porous structure offering enough tunnels for cells to flow through and enhancing aptamer-cell contact frequency, the spacer PEG with flexible and high hydrophilic property increasing anti-interference ability and providing the wafer with more binding sites for aptamer, which result in an enhanced capture specificity and efficiency for CTCs. Because of these advantages, the Ni@PDA-PEG-Apt wafer achieved a high capture efficiency of 78.25%. The captured cancer cells were mildly released by endonuclease with up to 61.85% efficiency and good proliferation. Furthermore, tumor cells were injected into mice and experienced circulation in vivo. In blood samples after circulation, 65% of target tumor cells can be efficiently captured by the wafer, followed by released and recultured cells with high viability. Further downstream metabolomics analysis showed that target cancer cells remained with high biological activity and can be well separated from MCF-10A cells based on metabolic profiles by the PCA analysis, indicating the great potential of our strategy for further research on the progression of cancer metastasis. Notably, not only is the wafer cheap with a cost of only 3.58 U.S. dollars and easily prepared by environmental-friendly reagents but also the process of capturing and releasing tumor cells can be completed within an hour, which is beneficial for large-scale clinical use in the future.

Efficient Isolation of Circulating Tumor Cells Using Ultra-Convenient Substrates Based on Self-Assembled Hollow MnO2 Nanoparticles

An efficient and active sorting platform of circulating tumor cells (CTCs) is still a challenge in clinical research. In this paper, we design a novel system based on hollow MnO2 nanoparticles for the capture and release of CTCs. Using the self-assembly method, we prepared rough MnO2 nanomaterial substrates that provide more binding sites for antibody grafting, increase the contact probability between cells and materials and improve the capture efficiency. The highest capture efficiency was 83.2% under the incubation time of 120 min. The MnO2 nanosubstrate was dissolved by employing a 2 × 10−3 M concentration of oxalic acid to release the captured cells. The cell release efficiency was up to 91.46% with a reaction time of 60 s. The released cells had a strong ability to proliferate after being collected and re-cultured for 24 h. Identifying and counting CTCs from the peripheral blood of breast cancer patients through the three-color immunocytochemistry method proved the effectiveness of our design platform. Such a simple and economical approach provides a promising platform for the capture and release of cells in clinical research.

Aptamer-mediated DNA concatemer functionalized magnetic nanoparticles for reversible capture and release of circulating tumor cells

Effectively capturing, releasing, and reanalyzing circulating tumor cells (CTCs) are critical in cancer diagnosis and individualized treatment. Traditional immunomagnetic separation has disadvantages of low sensitivity and specificity, and is time-consuming and costly in CTCs capture. It is also easily disturbed by the microenvironment in releasing and analyzing CTCs. Here, we proposed an aptamer-mediated DNA concatemer functionalized magnetic nanoparticles (MNPs-AMDC) for the reversible capture and release of CTCs. In this study, aptamers were used both for efficiently capturing CTCs without complicated assembly steps and stimulus-response switch for releasing CTCs with little influence on cellular activity. The MNPs-AMDC was demonstrated to effectively capture (83%) and release CTCs with a good viability rate (92%). Moreover, this device was also tested in clinical blood samples, which would provide a universal tool for diagnosing cancer and treating individuals.

Double-Tetrahedral DNA Probe Functionalized Ag Nanorod Biointerface for Effective Capture, Highly Sensitive Detection, and Nondestructive Release of Circulating Tumor Cells.

Circulating tumor cells (CTCs) are indicative of tumorigenesis, metastasis, and recurrence; however, it is still a great challenge to efficiently analyze the extremely rare CTCs in peripheral blood. Herein, a novel nanobiointerface integrating high affinities of arrayed silver nanorods (Ag NRs) and double-tetrahedral DNA (DTDN) probes by a clever strategy is proposed for the efficient capture, highly sensitive detection, and nondestructive release of CTCs. Under the optimal conditions, the DTDN-probe-functionalized Ag NRs nanobiointerface can capture 90.2% of SGC-7901 cells in PBS, and the capture efficiency is 2.8 times and 50 times those of a DTDN-probe-functionalized Ag film and unfunctionalized Ag NRs, respectively, benefiting from the nanorough interface of the Ag NRs array and multivalent recognition of the DTDN probe. In addition, 93.4% of cells was released via Zn2+-assisted DNAzyme cleavage, and the viability of the postreleased CTCs is about 98.0%. The potential practicality of the nanobiointerface for testing CTCs in blood was further characterized by spiking SGC-7901 cells in leukocytes collected from human blood, and the results show that 83.8% capture efficiency, 91.2% release efficiency, and single-cell detection limit were achieved, which indicates that the nanobiointerface has great potential in clinical applications for reliable CTC analyses.

Sensitive CTC analysis and dual-mode MRI/FL diagnosis based on a magnetic core-shell aptasensor

Synergizing the sensitive circulating tumor cell (CTC) capture, detection, release and the specific magnetic resonance/fluorescence (MR/FL) imaging for accurate cancer diagnosis is of great importance for cancer treatment. Herein, EcoR1-responsive complementary pairing of two ssDNA with a fluorescent P0 aptamer, which can specifically bind with the overexpressed MUC1 protein on cancer cells, was covalently modified to SiO2@C-coated magnetic nanoparticles for preparing a special nanoparticle-mediated FL turn-on aptasensor (FSC-D-P0). This aptasensor can selectively capture/enrich CTC and thus achieve sensitive CTC detection/imaging in even the blood due to its stable targeting, unique magnetic properties and the regulated interactions between the quencher and the fluorescent groups. Meanwhile, FSC-D-P0 can release the captured CTC for further downstream analysis upon the EcoR1 enzyme-triggered cleavage of the double-stranded DNA (dsDNA). Most importantly, this aptasensor can distinctly avoid false positivity of MRI via multiple targeting mechanisms. Thus, the sensitive CTC capture, detection, release and accurate MR/FL imaging were synergistically combined into a single platform with good biocompatibility, promising a robust pattern for clinical tumor diagnosis in vitro and in vivo.