Gelatin Nanoparticle-Coated Silicon Beads for Density-Selective Capture and Release of Heterogeneous Circulating Tumor Cells with High Purity

Immunomagnetic particles exhibiting programmable hierarchical flower-like nanostructures for enhanced separation of tumor cells

Immunomagnetic particles are extensively used for the separation of biological molecules and particles, and have exhibited great potential in many fields including biosensors, disease diagnosis and biomedical engineering. However, most immunomagnetic particles exhibit a smooth surface, resulting in a limited separation efficiency for biological particles featuring enormous surface nanostructures, such as tumor cells. Here we report flower-like immunomagnetic particles (FIMPs) prepared by streptavidin (SA)-assisted biomineralization and one-step antibody modification, and demonstrate their superior capability for highly efficient and selective separation of circulating tumor cells (CTCs). SA can link inorganic nanosheets and magnetic nanoparticles together to obtain FIMPs with programmable hierarchical flower-like nanostructures and provide enormous binding sites for post-antibody modification. The synergetic effect of nano-sized petals and micro-sized particles in the hierarchical nanostructure enhances the interaction between the cells and the matrix, thus enabling FIMPs to separate CTCs with high selectivity and high efficiency. Our study provides a promising platform for the selective separation of trace biological molecules and particles from complex samples and shows great potential for downstream detection and diagnosis.

Nanomaterial-Based Strategies for Preventing Tumor Metastasis by Interrupting the Metastatic Biological Processes

Tumor metastasis is the primary cause of cancer-related deaths. The prevention of tumor metastasis has garnered notable interest and interrupting metastatic biological processes is considered a potential strategy for preventing tumor metastasis. The tumor microenvironment (TME), circulating tumor cells (CTCs), and premetastatic niche (PMN) play crucial roles in metastatic biological processes. These processes can be interrupted using nanomaterials due to their excellent physicochemical properties. However, most studies have focused on only one aspect of tumor metastasis. Here, the hypothesis that nanomaterials can be used to target metastatic biological processes and explore strategies to prevent tumor metastasis is highlighted. First, the metastatic biological processes and strategies involving nanomaterials acting on the TME, CTCs, and PMN to prevent tumor metastasis are briefly summarized. Further, the current challenges and prospects of nanomaterials in preventing tumor metastasis by interrupting metastatic biological processes are discussed. Nanomaterial-and multifunctional nanomaterial-based strategies for preventing tumor metastasis are advantageous for the long-term fight against tumor metastasis and their continued exploration will facilitate rapid progress in the prevention, diagnosis, and treatment of tumor metastasis. Novel perspectives are outlined for developing more effective strategies to prevent tumor metastasis, thereby improving the outcomes of patients with cancer.

The integrated on-chip isolation and detection of circulating tumour cells

Circulating tumour cells (CTCs) are cancer cells shed from a primary tumour which intravasate into the blood stream and have the potential to extravasate into distant tissues, seeding metastatic lesions. As such, they can offer important insight into cancer progression with their presence generally associated with a poor prognosis. The detection and enumeration of CTCs is, therefore, critical to guiding clinical decisions during treatment and providing information on disease state. CTC isolation has been investigated using a plethora of methodologies, of which immunomagnetic capture and microfluidic size-based filtration are the most impactful to date. However, the isolation and detection of CTCs from whole blood comes with many technical barriers, such as those presented by the phenotypic heterogeneity of cell surface markers, with morphological similarity to healthy blood cells, and their low relative abundance (∼1 CTC/1 billion blood cells). At present, the majority of reported methods dissociate CTC isolation from detection, a workflow which undoubtedly contributes to loss from an already sparse population. This review focuses on developments wherein isolation and detection have been integrated into a single-step, microfluidic configuration, reducing CTC loss, increasing throughput, and enabling an on-chip CTC analysis with minimal operator intervention. Particular attention is given to immune-affinity, microfluidic CTC isolation, coupled to optical, physical, and electrochemical CTC detection (quantitative or otherwise).

Advances in the role of circulating tumor cell heterogeneity in metastatic small cell lung cancer

Small cell lung cancer (SCLC), a highly aggressive malignancy, is rapidly at an extensive stage once diagnosed and is one of the leading causes of death from malignancy. In the past decade, the treatment of SCLC has largely remained unchanged, and chemotherapy remains the cornerstone of SCLC treatment. The therapeutic value of adding immune checkpoint inhibitors to chemotherapy for SCLC is low, and only a few SCLC patients have shown a response to immune checkpoint inhibitors. Circulating tumor cells (CTCs) are tumor cells shed from solid tumor masses into the peripheral circulation and are key to tumor metastasis. Single-cell sequencing has revealed that the genetic profiles of individual CTCs are highly heterogeneous and contribute to the poor outcome and prognosis of SCLC patients. Theoretically, phenotypic analysis of CTCs may be able to predict the diagnostic significance of new potential targets for metastatic tumors. In this paper, we will discuss in depth the heterogeneity of CTCs in SCLC and the value of CTCs for the diagnosis and prognosis of SCLC and as relevant tumor markers in metastatic SCLC.

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.

Immunocapturing rare cells from blood: A simple and robust microsystem approach

Cell immunocapture microsystems are a fast-emerging field with several potential medical diagnostic applications. Isolation and quantification of circulating rare cells (CRCs) show great importance in the early stages of disease diagnostics and prognostics. Here, we present a simple and robust stop-flow microsystem (fabricated by a combination of glass microblasting and 3D printing) based on a planar antibody-coated surface that is effective in the immunocapture of the model as well as naturally occurring rare cells. A chip with a planar immunocapture channel working in the so-called stop-flow dynamic regime was designed to enable monitoring the efficiency of the cell capture by fluorescence microscopy. Up to 90% immunocapture efficiency of MCF-7 cells spiked into whole blood on CD326 antibody-coated planar surfaces was achieved. We discuss the role of the planar surface modifications, the influence of the set stop-flow dynamic conditions, and medium complexity on the efficiency of cell immunocapture. The presented results could be further employed in the design of microsystems for cell-size-independent isolation and identification of rare cells from blood.

Recent progress of nanostructure-based enrichment of circulating tumor cells and downstream analysis

The isolation and detection of circulating tumor cells (CTCs) play an important role in early cancer diagnosis and prognosis, providing easy access to identify metastatic cells before clinically detectable metastases. In the past 20 years, according to the heterogeneous expression of CTCs on the surface and their special physical properties (size, morphology, electricity, etc.), a series of in vitro enrichment methods of CTCs have been developed based on microfluidic chip technology, nanomaterials and various nanostructures. In recent years, the in vivo detection of CTCs has attracted considerable attention. Photoacoustic flow cytometry and fluorescence flow cytometry were used to detect CTCs in a noninvasive manner. In addition, flexible magnetic wire and indwelling intravascular non-circulating CTCs isolation system were developed for in vivo CTCs study. In the aspect of downstream analysis, gene analysis and drug sensitivity tests of enriched CTCs were developed based on various existing molecular analysis techniques. All of these studies constitute a complete study of CTCs. Although the existing reviews mainly focus on one aspect of capturing CTCs study, a review that includes the in vivo and in vitro capture and downstream analysis study of CTCs is highly needed. This review focuses on not only the classic work and latest research progress in in vitro capture but also includes the in vivo capture and downstream analysis, discussing the advantages and significance of the different research methods and providing new ideas for solving the heterogeneity and rarity of CTCs.

An ultra-compact acoustofluidic device based on the narrow-path travelling surface acoustic wave (np-TSAW) for label-free isolation of living circulating tumor cells

Obtaining highly purified intact living cells from complex environments has been a challenge, such as the isolation of circulating tumor cells (CTCs) from blood. In this work, we demonstrated an acoustic-based ultra-compact device for cell sorting, with a chip size of less than 2 × 1.5 cm². This single actuator device allows non-invasive and label-free isolation of living cells, offering greater flexibility and applicability. The device performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with cancer cells. Using the narrow-path travelling surface acoustic wave (np-TSAW), precise isolation of 10 μm particles from a complex mixture of particles (5, 10, 20 μm) and separation of 8 μm and 10 μm particles was achieved. The purified collection of 10 μm particles with high separation efficiency (98.75%) and high purity (98.1%) was achieved by optimizing the input voltage. Further, we investigated the isolation and purification of CTCs (MCF-7, human breast cancer cells) from blood cells with isolation efficiency exceeding 98% and purity reaching 93%. Viabilities of the CTCs harvested from target-outlet were all higher than 97% after culturing for 24, 48, and 72 h, showing good proliferation ability. This novel ultra-miniaturized microfluidic chip demonstrates the ability to sorting cells with high-purity and label-free, providing an attractive miniaturized system alternative to traditional sorting methods.

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.

Isolation, Detection and Analysis of Circulating Tumour Cells: A Nanotechnological Bioscope

Cancer is one of the dreaded diseases to which a sizeable proportion of the population succumbs every year. Despite the tremendous growth of the health sector, spanning diagnostics to treatment, early diagnosis is still in its infancy. In this regard, circulating tumour cells (CTCs) have of late grabbed the attention of researchers in the detection of metastasis and there has been a huge surge in the surrounding research activities. Acting as a biomarker, CTCs prove beneficial in a variety of aspects. Nanomaterial-based strategies have been devised to have a tremendous impact on the early and rapid examination of tumor cells. This review provides a panoramic overview of the different nanotechnological methodologies employed along with the pharmaceutical purview of cancer. Initiating from fundamentals, the recent nanotechnological developments toward the detection, isolation, and analysis of CTCs are comprehensively delineated. The review also includes state-of-the-art implementations of nanotechnological advances in the enumeration of CTCs, along with future challenges and recommendations thereof.

Ultrathin silicon nitride membrane with slit-shaped pores for high-performance separation of circulating tumor cells

In this study, we developed an ultrathin filtering membrane with slit-shaped pores which can achieve circulating tumor cell (CTC) separation from whole blood with high performance (high capture efficiency, high white blood cell (WBC) depletion, and high viability). The silicon nitride (Si₃N₄) filtering membrane was fabricated via the standard microfabrication technology, which can be easily scaled up to mass-production. 6 μm was determined as the optimum width of the filtering pores to better separate CTCs in whole blood, which can reach a high capture efficiency of ∼96%. Meanwhile, the filtering membrane with a high porosity of 34% demonstrated high WBC depletion (∼99.99%). Furthermore, the ultrathin (thickness: 200 nm) Si₃N₄ membrane facilitated the capture of CTCs with high viability (∼90%). Finally, the microfluidic chip was successfully applied to separate CTCs in whole blood samples from cancer patients and used for molecular examination. These results indicate that this microfluidic chip facilitates the clinical application of CTC-based liquid biopsy technology.

Nanotechnology: A Promising Approach for Cancer Diagnosis, Therapeutics and Theragnosis

Cancer remains the most devastating disease and the major cause of mortality worldwide. Although early diagnosis and treatment are the key approach in fighting against cancer, the available conventional diagnostic and therapeutic methods are not efficient. Besides, ineffective cancer cell selectivity and toxicity of traditional chemotherapy remain the most significant challenge. These limitations entail the need for the development of both safe and effective cancer diagnosis and treatment options. Due to its robust application, nanotechnology could be a promising method for in-vivo imaging and detection of cancer cells and cancer biomarkers. Nanotechnology could provide a quick, safe, cost-effective, and efficient method for cancer management. It also provides simultaneous diagnosis and treatment of cancer using nano-theragnostic particles that facilitate early detection and selective destruction of cancer cells. Updated and recent discussions are important for selecting the best cancer diagnosis, treatment, and management options, and new insights on designing effective protocols are utmost important. This review discusses the application of nanotechnology in cancer diagnosis, therapeutics, and theragnosis and provides future perspectives in the field.

Advances in the Biology, Detection Techniques, and Clinical Applications of Circulating Tumor Cells

Circulating tumor cells (CTCs) play a crucial role in tumor recurrence and metastasis, and their early detection has shown remarkable benefits in clinical theranostics. However, CTCs are extremely rare, thus detecting them in the blood is very challenging. New CTC detection techniques are continuously being developed, enabling deeper analysis of CTC biology and potential clinical application. This article reviews current CTC detection techniques and their clinical application. CTCs have provided, and will continue to provide, important insights into the process of metastasis, which could lead to development of new therapies for different cancers.

Bovine serum albumin-gold nanoclusters protein corona stabilized polystyrene nanoparticles as dual-color fluorescent nanoprobes for breast cancer detection

Breast cancer is the most prevalent malignancy and the first leading cause of cancer-related mortality among the female population worldwide. Approaches for precise and reliable detection of breast cancer cells, particularly in the nascent state, are desperately needed for elevating the survival rate of patients bearing the breast tumor. In this work, we successfully performed the sensitive, precise, and reliable breast cancer cell detection using facilely fabricated bovine serum albumin-gold nanocluster (BSA-AuNCs) protein corona stabilized, epithelial cell adhesion molecule (EpCAM) aptamer linked fluorescent polystyrene nanoparticle (PS NP), termed as PS-BSA-AuNCs-Apt. The rapidly adsorbed BSA-AuNCs hard protein corona without complicated covalent conjugation not only imparted excellent colloidal stability to the PS nanoparticles, but also offered numerous active anchors for the targeted EpCAM aptamers to locate. With the remarkable aid of the aptamers specifically targeting the EpCAM-positive breast cancer cells, the PS-BSA-AuNCs-Apt emitted strong and photostable dual-color fluorescent signals for precise and reliable cancer cell detection by overcoming the false signals. The specific identification potency of the PS-BSA-AuNCs-Apt system was further verified by successfully detecting the xenografted breast tumor tissue. Notably, to the best of our knowledge, the protein corona formed nanoprobes was exploited for direct tumor cell and tissue detection with high efficacy for the first time, demonstrating their promising potential in clinical tumor detection.

Neutrophil membrane-coated immunomagnetic nanoparticles for efficient isolation and analysis of circulating tumor cells

The isolation and analysis of scarce circulating tumor cells (CTCs) with immunomagnetic nanoparticles (IMNs) have shown promising outcomes in noninvasive cancer diagnosis. However, the IMNs adsorb nonspecific proteins after entering into biofluids and the formed protein coronas cover surface targeting ligands, limiting the detection efficiency of IMNs. In addition, the interaction between surface targeting ligands and white blood cells (WBCs) significantly limits the purity of CTCs isolated by IMNs. Furthermore, the interfacial collision of nanoparticles and cells has negative effects on the viability of isolated CTCs. All of these limitations synthetically restrict the isolation and analysis of rare CTCs for early diagnosis and precision medicine. Here, we proposed that surface functionalization of IMNs with neutrophil membranes can simultaneously reduce nonspecific protein adsorption, enhance the interaction with CTCs, reduce the distraction from WBCs, and improve the viability of isolated CTCs. In spiked blood samples, our neutrophil membrane-coated IMNs (Neu-IMNs) exhibited a superior separation efficiency from 41.36% to 96.82% and an improved purity from 40.25% to 90.68% when compared to bare IMNs. Additionally, we successfully isolated CTCs in 19 out of total 20 blood samples from breast cancer patients using Neu-IMNs and further confirmed the feasibility of the isolated CTCs for downstream cell sequencing. Our work provides a new perspective on engineered IMNs for efficient isolation and analysis of CTCs, paving the way for early noninvasive diagnosis of cancer.

Noninvasive Optical Isolation and Identification of Circulating Tumor Cells Engineered by Fluorescent Microspheres

Circulating tumor cells (CTCs) are rare, meaning that current isolation strategies can hardly satisfy efficiency and cell biocompatibility requirements, which hinders clinical applications. In addition, the selected cells require immunofluorescence identification, which is a time-consuming and expensive process. Here, we developed a method to simultaneously separate and identify CTCs by the integration of optical force and fluorescent microspheres. Our method achieved high-purity separation of CTCs without damage through light manipulation and avoided additional immunofluorescence staining procedures, thus achieving rapid identification of sorted cells. White blood cells (WBCs) and CTCs are similar in size and density, which creates difficulties in distinguishing them optically. Therefore, fluorescent PS microspheres with high refractive index (RI) are designed here to capture the CTCs (PS-CTCs) and increase the average index of refraction of PS-CTCs. In optofluidic chips, PS-CTCs were propelled to the collection channel from the sample mixture, under the radiation of light force. Cells from the collection outlet were easily identified under a fluorescence microscope due to the fluorescence signals of PS microspheres. This method provides an approach for the sorting and identification of CTCs, which holds great potential for clinical applications in early diagnosis of disease.

Nanomaterial-Based Immunocapture Platforms for the Recognition, Isolation, and Detection of Circulating Tumor Cells

Circulating tumor cells (CTCs) are a type of cancer cells that circulate in the peripheral blood after breaking away from solid tumors and are essential for the establishment of distant metastasis. Up to 90% of cancer-related deaths are caused by metastatic cancer. As a new type of liquid biopsy, detecting and analyzing CTCs will provide insightful information for cancer diagnosis, especially the in-time disease status, which would avoid some flaws and limitations of invasive tissue biopsy. However, due to the extremely low levels of CTCs among a large number of hematologic cells, choosing immunocapture platforms for CTC detection and isolation will achieve good performance with high purity, selectivity, and viability. These properties are directly associated with precise downstream analysis of CTC profiling. Recently, inspired by the nanoscale interactions of cells in the tissue microenvironment, platforms based on nanomaterials have been widely explored to efficiently enrich and sensitively detect CTCs. In this review, various immunocapture platforms based on different nanomaterials for efficient isolation and sensitive detection of CTCs are outlined and discussed. First, the design principles of immunoaffinity nanomaterials are introduced in detail. Second, the immunocapture and release of platforms based on nanomaterials ranging from nanoparticles, nanostructured substrates, and immunoaffinity microfluidic chips are summarized. Third, recent advances in single-cell release and analysis of CTCs are introduced. Finally, some perspectives and challenges are provided in future trends of CTC studies.

A light-induced hydrogel responsive platform to capture and selectively isolate single circulating tumor cells

Isolation of circulating tumor cells (CTCs) from patients is a challenge due to the rarity of CTCs. Recently, various platforms to capture and release CTCs for downstream analysis have been developed. However, most of the reported release methods provide external stimuli to release all captured cells, which lead to lack of specificity in the pool of collected cells, and the external stimuli may affect the activity of the released cells. Here, we presented a simple method for single-cell recovery to overcome the shortcomings, which combined the nanostructures with a photocurable hydrogel, chondroitin sulfate methacryloyl (CSMA). In brief, we synthesized gelatin nanoparticles (Gnps) and modified them on flat glass (Gnp substrate) for the specific capture of CTCs. A 405 nm laser was projected onto the selected cells, and then CSMA was cured to encapsulate the selected CTCs. Unselected cells were removed with MMP-9 enzyme solution, and selected CTCs were recovered using a microcapillary. Finally, the photocurable hydrogel-encapsulated cells were analyzed by nucleic acid detection. In addition, the results suggested that the isolation platform showed good biocompatibility and successfully achieved the isolation of selected cells. In summary, our light-induced hydrogel responsive platform holds certain potential for clinical applications.

Ultrahigh SERS Activity of TiO2@Ag Nanostructure leveraged for Accurately Detecting CTCs in peripheral blood

Circulating tumor cells (CTCs) usually shed from primary and metastatic tumors serve as an important tumor marker, and easily cause fatal distant metastasis in cancer patients. Accurately and effectively detecting...

A review of enrichment methods for circulating tumor cells: from single modality to hybrid modality

Circulating tumor cell (CTC) analysis as a liquid biopsy can be used for early diagnosis of cancer, evaluating cancer progression, and assessing treatment efficacy. The enrichment of CTCs from patient blood is important for CTC analysis due to the extreme rarity of CTCs. This paper updates recent advances in CTC enrichment methods. We first review single-modality methods, including biophysical and biochemical methods. Hybrid-modality methods, combining at least two single-modality methods, are gaining increasing popularity for their improved performance. Then this paper reviews hybrid-modality methods, which are categorized into integrated and sequenced hybrid-modality methods. The state of the art indicates that the CTC capture efficiencies of integrated hybrid-modality methods can reach 85% or higher by taking advantage of the superimposed and enhanced capture effects from multiple single-modality methods. Moreover, a hybrid method integrating biophysical with biochemical methods is characterized by both high processing rate and high specificity.

Isolation of Circulating Tumor Cells from Peripheral Blood Samples of Cancer Patients Using Microfluidic Technology

The aim of the investigation was to study the potential of an innovative microfluidic technology for the isolation of circulating tumor cells (CTCs) from the peripheral blood samples of cancer patients.

Detection and clinical significance of circulating tumor cells in colorectal cancer

Histopathological examination (biopsy) is the "gold standard" for the diagnosis of colorectal cancer (CRC). However, biopsy is an invasive method, and due to the temporal and spatial heterogeneity of the tumor, a single biopsy cannot reveal the comprehensive biological characteristics and dynamic changes of the tumor. Therefore, there is a need for new biomarkers to improve CRC diagnosis and to monitor and treat CRC patients. Numerous studies have shown that "liquid biopsy" is a promising minimally invasive method for early CRC detection. A liquid biopsy mainly samples circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), microRNA (miRNA) and extracellular vesicles (EVs). CTCs are malignant cells that are shed from the primary tumors and/or metastases into the peripheral circulation. CTCs carry information on both primary tumors and metastases that can reflect dynamic changes in tumors in a timely manner. As a promising biomarker, CTCs can be used for early disease detection, treatment response and disease progression evaluation, disease mechanism elucidation, and therapeutic target identification for drug development. This review will discuss currently available technologies for plasma CTC isolation and detection, their utility in the management of CRC patients and future research directions.

Electrochemical micro-aptasensors for exosome detection based on hybridization chain reaction amplification

Exosomes are cell-derived nanovesicles that have recently gained popularity as potential biomarkers in liquid biopsies due to the large amounts of molecular cargo they carry, such as nucleic acids and proteins. However, most existing exosome-based analytical sensing methods struggle to achieve high sensitivity and high selectivity simultaneously. In this work, we present an electrochemical micro-aptasensor for the highly sensitive detection of exosomes by integrating a micropatterned electrochemical aptasensor and a hybridization chain reaction (HCR) signal amplification method. Specifically, exosomes are enriched on CD63 aptamer-functionalized electrodes and then recognized by HCR products with avidin-horseradish peroxidase (HRP) attached using EpCAM aptamers as bridges. Subsequently, the current signal that is generated through the enzyme reaction between the HRP enzyme and 3,3',5,5'-tetramethylbenzidine (TMB)/H2O2 directly correlates to the amount of bound HRP on the HCR products and thus to the number of target exosomes. By introducing anti-EpCAM aptamers, micro-aptasensors can detect cancerous exosomes with high specificity. Due to the micropatterned electrodes and HCR dual-amplification strategy, the micro-aptasensors achieve a linear detection response for a wide range of exosome concentrations from 2.5×103 to 1×107 exosomes/mL, with a detection limit of 5×102 exosomes/mL. Moreover, our method successfully detects lung cancer exosomes in serum samples of early-stage and late-stage lung cancer patients, showcasing the great potential for early cancer diagnosis.

Detection of circulating tumor cells: Advances and critical concerns

Metastasis is the main cause of cancer-related death and the major challenge in cancer treatment. Cancer cells in circulation are termed circulating tumor cells (CTCs). Primary tumor metastasis is likely due to CTCs released into the bloodstream. These CTCs extravasate and form fatal metastases in different organs. Analyses of CTCs are clarifying the biological understanding of metastatic cancers. These data are also helpful to monitor disease progression and to inform the development of personalized cancer treatment-based liquid biopsy. However, CTCs are a rare cell population with 1-10 CTCs per ml and are difficult to isolate from blood. Numerous approaches to detect CTCs have been developed based on the physical and biological properties of the cells. The present review summarizes the progress made in detecting CTCs.

Antifouling hydrogel-coated magnetic nanoparticles for selective isolation and recovery of circulating tumor cells

For reliable downstream molecular analysis, it is crucially important to recover circulating tumor cells (CTCs) from clinical blood samples with high purity and viability. Herein, magnetic nanoparticles coated with an antifouling hydrogel layer based on the polymerization method were developed to realize cell-friendly and efficient CTC capture and recovery. Particularly, the hydrogel layer was fabricated by zwitterionic sulfobetaine methacrylate (SBMA) and methacrylic acid (MAA) cross-linked with N,N-bis(acryloyl)cystamine (BACy), which could not only resist nonspecific adhesion but also gently recover the captured cells by glutathione (GSH) responsiveness. Moreover, the anti-epithelial cell adhesion molecule (anti-EpCAM) antibody was modified onto the surface of the hydrogel to provide high specificity for CTC capture. As a result, 96% of target cells were captured in the mimic clinical blood samples with 5-100 CTCs per mL in 25 min of incubation time. After the GSH treatment, about 96% of the obtained cells were recovered with good viability. Notably, the hydrogel-coated magnetic nanoparticles were also usefully applied to isolate CTCs from the blood samples of cancer patients. The favorable results indicate that the hydrogel-modified magnetic nanoparticles may have a promising opportunity to capture and recover CTCs for subsequent research.

Anticlogging Hemofiltration Device for Mass Collection of Circulating Tumor Cells by Ligand-Free Size Selection

A new hemofiltration system was developed to continuously capture circulating tumor cells (CTCs) from a large volume of whole blood using a column that was packed with antifouling zwitterionized silica microspheres. The silica microspheres were modified with sulfobetaine silane (SBSi) to inhibit fouling, resist clogging, and give a high surface wettability and prolonged operation time. Packed microspheres with different diameters formed size-controllable interstitial pores that effectively captured CTCs by ligand-free size selection. For optimized performance of the hemofiltration system, operational factors, including the size of microspheres, flow rate, and cross-sectional area of the column, were considered with respect to the removal rate for colorectal cancer cells and the retention rate for white blood cells and red blood cells. The captured CTCs were collected from the column by density sedimentation. A large quantity of colorectal cancer cells was spiked into sheep blood, and the sample was circulated for 5 h with a total operational volume of 2 L followed by collection and culture in vitro. The results showed that the proposed hemofiltration device selectively removed abundant CTCs from in vitro circulatory blood. The viable cells were harvested for amplification and potential applications for precision medicine.

Effect of Engineered Nickel Oxide Nanoparticle on Reactive Oxygen Species-Nitric Oxide Interplay in the Roots of Allium cepa L

Scientists anxiously follow instances of heavy metals augmenting in the environment and undergoing bioaccumulation and trace their biomagnification across food webs, wary of their potent toxicity on biological entities. Engineered nanoparticles supplement natural pools of respective heavy metals and can mimic their effects, exerting toxicity at higher concentrations. Thus, a thorough understanding of the underlying mechanism of this precarious interaction is mandatory. Most urban and industrial environments contain considerable quantities of nickel oxide nanoparticles. These in excess can cause considerable damage to plant metabolism through a significant increase in cellular reactive oxygen species and perturbation of its cross-talk with the reactive nitrogen species. In the present work, the authors have demonstrated how the intrusion of nickel oxide nanoparticles (NiO-NP) affected the exposed roots of Allium cepa: starting with disruption of cell membranes, before being interiorized within cell organelles, effectively disrupting cellular homeostasis and survival. A major shift in the reactive oxygen species (ROS) and nitric oxide (NO) equanimity was also observed, unleashing major altercations in several crucial biochemical profiles. Altered antioxidant contents and upregulation of stress-responsive genes, namely, Catalase, Ascorbate peroxidase, Superoxide dismutase, and Rubisco activase, showing on average 50-250% rise across NiO-NP concentrations tested, also entailed increased cellular hydrogen peroxide contents, with tandem rise in cellular NO. Increased NO content was evinced from altered concentrations of nitric oxide synthase and nitrate reductase, along with NADPH oxidase, when compared with the negative control. Though initially showing a dose-dependent concomitant rise, a significant decrease of NO was observed at higher concentrations of NiO-NP, while cellular ROS continued to increase. Modified K/Na ratios, with increased proline concentrations and GABA contents, all hallmarks of cellular stress, correlated with ROS-NO perturbations. Detailed studies showed that NiO-NP concentration had a significant role in inducing toxicity, perturbing the fine balance of ROS-NO, which turned lethal for the cell at higher dosages of the ENP precipitating in the accumulation of stress markers and an inevitable shutdown of cellular mechanisms.

Electrospun degradable Zn-Mn oxide hierarchical nanofibers for specific capture and efficient release of circulating tumor cells

Constructing biological affinity devices is considered as an effective strategy for isolating circulating tumor cells (CTCs), and electrospun nanofibers (ESNFs) have recently received attention. However, the current research focuses on polymer fibers, and fabricating stimuli-responsive inorganic nanofibers for cancer diagnosis and analysis is still challenging. In this work, Zn-Mn oxide nanofibers (ZnMnNFs) are used to capture and purify cancer cells after modification with specific antibodies. Then, the hierarchical nanofibers are degraded by reductive weak acid to release the captured cells efficiently without residues. Fusion of Zn and Mn, two transition metals, enhances the surface activity of oxides so that ZnMnNFs are easier to be degraded and modified. By using MCF-7 cancer cells, the cell capture efficiency of ZnMnNFs is up to 88.2%. Furthermore, by using citric acid, it is discovered that, by comparison with Mn oxide nanofibers, the cell release efficiency of ZnMnNFs is improved to 95.1% from 15.4%. In addition, the viability of released cells exceeds 90%. Lastly, the robustness of ZnMnNFs substrates is tested in peripheral blood from breast cancer patients (BCP) and colorectal cancer patients (CCP). Combined with fluorescence labeling, CTCs are confirmed to be isolated from all the clinical samples. This is the first trial of using ternary inorganic ESNFs for cancer cell capture. It is anticipated that the degradable ESNFs will provide biocompatible theranostic platforms and overcome the current limitations of cell release for high-precision gene analysis.

Isolation of DNA aptamers targeting N-cadherin and high-efficiency capture of circulating tumor cells by using dual aptamers

Circulating tumor cells (CTCs) acquire mesenchymal markers (e.g., N-cadherin) and lose epithelial markers (e.g., epithelial cell adhesion molecule, EpCAM) during the epithelial-mesenchymal transition (EMT) and are therefore ideal biomarkers of tumor metastasis. However, it is still a challenge to efficiently capture and detect circulating tumor cells with different phenotypes simultaneously. In this work, to obtain aptamers targeting N-cadherin in the native conformation on live cells, we established stable N-cadherin overexpressing cells (N-cadherin cells) and used these cells to identify a panel of N-cadherin-specific aptamers through the cell-SELEX approach. Two aptamer candidates obtained after 12 rounds of selection showed a low equilibrium dissociation constant in the nanomolar range, indicating high binding affinity. The truncated aptamer candidate NC3S showed the highest binding affinity to N-cadherin cells with a low Kd value of 20.08 nM. The SYL3C aptamer was reported to target cancer cell surface biomarker EpCAM. Then, we synthesized two kinds of aptamer-modified magnetic nanoparticles (SYL3C-MNPs and NC3S-MNPs). Both SYL3C and NC3S aptamers possess excellent capture specificity and efficiency for the target cells. The aptamer-MNP cocktail exhibits a considerable capture efficiency and sensitivity for rare cancer cells of epithelial and mesenchymal phenotypes. Furthermore, no CTCs were found in blood samples from healthy donors, while CTCs were successfully isolated by using the aptamer-MNP cocktail for 15 out of 16 samples collected from patients. In summary, the two kinds of aptamer-modified MNPs could be utilized as a promising tool for capturing CTCs from clinical samples.

High-throughput isolation of fetal nucleated red blood cells by multifunctional microsphere-assisted inertial microfluidics

Being easy, safe and reliable, non-invasive prenatal diagnosis (NIPD) has been greatly pursued in recent years. Holding the complete genetic information of the fetus, fetal nucleated red blood cells (fNRBCs) are viewed as a suitable target for NIPD application. However, effective separating fNRBCs from maternal peripheral blood for clinic use still faces great challenges, given that fNRBCs are extremely rare in maternal blood circulation. Here, by combining the high-throughput inertial microfluidic chip with multifunctional microspheres as size amplification, we develop a novel method to isolate fNRBCs with high performance. To enlarge the size difference between fNRBCs and normal blood cells, we use the gelatin coated microspheres to capture fNRBCs with anti-CD147 as specific recognizer at first. The size difference between fNRBCs captured by the microspheres and normal blood cells makes it easy to purify the captured fNRBCs through the spiral microfluidic chip. Finally, the purified fNRBCs are mildly released from the microspheres by enzymatically degrading the gelatin coating. Cell capture efficiency about 81%, high purity of 83%, as well as cell release viability over 80% were achieved using spiked samples by this approach. Additionally, fNRBCs were successfully detected from peripheral blood of pregnant women with an average of 24 fNRBCs per mL, suggesting the great potential of this method for clinical non-invasive prenatal diagnosis.

Dopamine-functionalized hyaluronic acid microspheres for effective capture of CD44-overexpressing circulating tumor cells

As one of the biomarkers of liquid biopsy, circulating tumor cells (CTCs) provides important clinical information for cancer diagnosis. However, accurate separation and identification of CTCs remains a great deal of challenge. In present work, we developed novel dopamine-functionalized hyaluronic acid microspheres (HA-DA microspheres) to capture CD44-overexpressing CTCs. The dopamine was grafted onto the hyaluronic acid chain, which was polymerized and cross-linked by oxidation of the catechol groups. Afterwards, a facile microfluidic chip was designed and developed to fabricate the HA-DA microspheres with a diameter of about 45 μm. Our results showed that the CD44+ cells (i.e., HeLa, HepG2, A549, MCF-7 and DU-145 cells) could be selectively captured. Then a double-layer microfluidic filter (DLMF) was fabricated for dynamic isolation and detection of CTCs in blood samples. Many slit openings with 15 μm in height were designed to allow white blood cells to clear away, while the microspheres with CTCs were intercepted in the DLMF, which achieved effective separation of CTCs from blood cells. The approach exhibited high capture efficiency even at the cell density as low as 10 cells/mL. We believe the DLMF integrated with HA-DA microspheres could be a promising approach for isolation and detection of CD44-overexpressing CTCs, which is useful for prognosis and early metastasis of cancer patients.

Clinical value and feasibility of ISET in detecting circulating tumor cells in early breast cancer

Background

Patients with operable breast cancer have a better prognosis for recovery. However, once distant organ metastasis occurs, the chance of a long-term survival or a cure is limited. The collection and counting of circulating tumor cells (CTCs) by reliable detection techniques are of increasing importance in the diagnosis of early metastasis and prognosis of disease progression. Isolation by size of epithelial tumor cells (ISET) has the advantage of simplicity of operation and high homogeneity. It is practical for large-scale clinical detection showing cell abundance. The value of ISET in the detection of circulating breast cancers in the blood has not been determined. The purpose of this study is to explore the feasibility of applying ISET to detect CTCs by determining the detection rate of ISET in operable breast cancer and by evaluating the correlation between detection rate, cell count and clinical factors such as molecular typing and pathological staging.

Methods

The experiment included 193 breast cancer patients who were diagnosed by core needle biopsy before the operation. 10 mL of venous blood was collected from the patients preoperatively, and CTCs in their blood samples were counted and analyzed by ISET.

Results

Patients were divided into groups according to pathology and immunohistochemistry. The overall detection rate of CTCs by ISET was 41.24%. The detection rate, the number of overall CTCs and the average number of CTCs in each group were analyzed individually. No significant differences were observed between the different groups.

Conclusions

Although ISET has a relatively good detection rate for circulating breast cancer cells, it fails to provide more information on pathological staging, molecular classification and so forth.

Positively Charged Magnetic Nanoparticles for Capture of Circulating Tumor Cells from Clinical Blood Samples

Isolation of circulating tumor cells (CTCs) from cancer patients is of high value for disease monitoring and metastasis diagnosis. Although many new detection methods have emerged in recent years, the detection of CTCs is a current challenge due to lack of specific and sensitive markers. In our previous work, cancer cell surfaces, from over 20 cancer cell lines, have been shown to be negatively-charged regardless of their phenotype by using electrically-charged nanoparticles as a probe. The strong electrostatic interaction between the negative cancer cells and positively charged nanoparticles can well remain in a physiological liquid environment in the presence of serum proteins, enabling effective binding between them. As a result, the cancer cells can be magnetically separated by employing an external magnet. In this technical report, we present preliminary results on the investigation of CTC isolation from both mimetic and clinical blood samples. We show high CTC detection sensitivity by the positively-charged magnetic nanoparticles (PMNs) even at the original concentration of 10 cells per mL mimetic blood sample. The CTCs in the peripheral blood of colorectal cancer patients were isolated and identified by cellular morphology and immunofluorescence staining.

Nanotechnology in cancer diagnosis: progress, challenges and opportunities

In the fight against cancer, early detection is a key factor for successful treatment. However, the detection of cancer in the early stage has been hindered by the intrinsic limits of conventional cancer diagnostic methods. Nanotechnology provides high sensitivity, specificity, and multiplexed measurement capacity and has therefore been investigated for the detection of extracellular cancer biomarkers and cancer cells, as well as for in vivo imaging. This review summarizes the latest developments in nanotechnology applications for cancer diagnosis. In addition, the challenges in the translation of nanotechnology-based diagnostic methods into clinical applications are discussed.

An Acoustic Droplet-Induced Enzyme Responsive Platform for the Capture and On-Demand Release of Single Circulating Tumor Cells

The recovery of rare single circulating tumor cells (CTCs) from patients has great potential to facilitate the study of cell heterogeneity and cancer metastasis, which may promote the development of individualized cancer immunotherapy. Herein, a versatile single-cell recovery approach that utilizes an acoustic droplet-induced enzyme responsive platform for the capture and on-demand release of single CTCs is proposed. The platform combines a multifunctional enzyme-responsive gelatin nanoparticle (GNP)-decorated substrate (GNP-chip) for specific capture with an acoustic droplet positioning technique to realize on-demand release of single CTCs. The acoustic droplet dispenser is employed to generate oxidized alginate microdroplets containing the MMP-9 enzyme (OA-MMP-9) with controllable size and precise positioning upon the cell-attached GNP-chip, allowing controlled cell-surface biodegradation under enzymatic reactions followed by calcium chloride (CaCl₂) solution treatment to form single-cell encapsulated calcium alginate hydrogels. Benefitting from the existence of hydrogels, the released cells could be efficiently recovered by microcapillary. Results demonstrate that the encapsulated cells maintain good cell morphology in the hydrogels, which allow further single-cell nucleic acid analysis. As a proof-of-concept platform, this approach enables reliable and efficient retrieval of single CTCs and holds the potential for versatility in single-cell analysis systems.

High-Efficiency Isolation and Rapid Identification of Heterogeneous Circulating Tumor Cells (CTCs) Using Dual-Antibody-Modified Fluorescent-Magnetic Nanoparticles

Extreme rarity and inherent heterogeneity of circulating tumor cells (CTCs) result in a tremendous challenge for the CTC isolation from patient blood samples with high efficiency and purity. Current CTC isolation approaches mainly rely on the epithelial cell adhesion molecule (EpCAM), which may significantly reduce the ability to capture CTCs when the expression of EpCAM is lost or down-regulated in epithelial-mesenchymal transition. Here, a rapid and highly efficient method is developed to isolate and identify heterogeneous CTCs with high efficiency from patient blood samples using the fluorescent-magnetic nanoparticles (F-MNPs). A dual-antibody interface targeting EpCAM and N-cadherin is fabricated onto the F-MNPs to capture epithelial CTCs as well as mesenchymal CTCs from whole blood samples. The poly(carboxybetaine methacrylate) brushes of excellent antifouling properties are employed to decrease nonspecific cell adhesion. Moreover, the F-MNPs provide a prompt identification strategy for heterogeneous CTCs (F-MNPs+, Hoechst 33342+, and CD45-) that can directly identify CTCs in a gentle one-step processing within 1 h after isolation from patient blood samples. This has been demonstrated through artificial samples as well as patient samples in details.

TiO2 nanopillar arrays coated with gelatin film for efficient capture and undamaged release of circulating tumor cells

Circulating tumor cells (CTCs) are important for the detection and treatment of cancer. Nevertheless, a low density of circulating tumor cells makes the capture and release of CTCs an obstacle. In this work, TiO₂ nanopillar arrays coated with gelatin film were synthesized for efficient capture and undamaged release of circulating tumor cells. The scanning electron microscope and atomic force microscope images demonstrate that the substrate has a certain roughness. The interaction between the cell membrane and the nanostructure substrate contributes to the efficient capture of CTC (capture efficiency up to 94.98%). The gelatin layer has excellent biocompatibility and can be rapidly digested by matrix metalloproteinase (MMP9), which realizes the non-destructive release of CTCs (0.1 mg ml^-1, 5 min, nearly 100% release efficiency, activity 100%). Therefore, by our strategy, the CTCs can be efficiently captured and released undamaged, which is important for subsequent analysis.

Biomimetic Immunomagnetic Nanoparticles with Minimal Nonspecific Biomolecule Adsorption for Enhanced Isolation of Circulating Tumor Cells

Immunomagnetic micro/nanoparticles (IMNs) have been widely used to isolate rare circulating tumor cells (CTCs) from blood samples for early diagnosis of cancers. However, when entering into biofluids, IMNs nonspecifically adsorb biomolecules and the in situ formed biomolecule corona covers IMN surface ligands and weakens the targeting capabilities of IMNs. In this work, we demonstrated that by surface coating of IMNs with red blood cell (RBC)-derived vesicles, the obtained biomimetic particles (RBC-IMNs) basically adsorb no biomolecules and maintain the CTC targeting ability when exposed to plasma. Compared to IMNs, RBC-IMNs exhibited an excellent cell isolation efficiency in spiked blood samples, which was improved to 95.71% from 60.22%. Furthermore, by using RBC-IMNs, we successfully isolated CTCs in 28 out of 30 prostate cancer patient blood samples and further showed the robustness of RBC-IMNs in downstream cell sequencing. The work presented here provides a new insight into developing targeted nanomaterials for biological and medical applications.

Precise and non-invasive circulating tumor cell isolation based on optical force using homologous erythrocyte binding

Precise isolation of circulating tumor cells (CTCs) is proved to be significant for early cancer diagnosis and downstream analysis. Most of the existing strategies yield low purity or cause unexpected damage to cells because of foreign material introduction. To avoid foreign material caused damage and achieve high efficiency simultaneously, this work presents an innovative strategy using tumor cell targeting molecules to bind homologous red blood cells (RBCs) with tumor cells, which results in obvious optical constant differences (both size and mean refractive index) between CC-RBCs (RBC conjugated CTCs) and other blood cells. Then the modified CTCs can be precisely separated under laser illumination in an optofluidic system. Experiments show that CTCs are efficiently modified with erythrocytes and finally isolated from blood at high purity (more than 92%) and a high recovery rate (over 90%). In the whole process, CTCs are proved to keep membrane and function integrity. The combination of homologous RBC binding and an optofluidic system will provide a convenient tool for cancer early diagnosis and treatment monitoring, which exhibits good performance in CTC non-invasive and precise isolation, thus showing great potential.

Advances in liquid biopsy using circulating tumor cells and circulating cell-free tumor DNA for detection and monitoring of breast cancer

Overview the progress of liquid biopsy using circulating tumor cells (CTCs) and circulating cell-free tumor DNA (cfDNA) to detect and monitor breast cancer. Based on numerous research efforts, the potential value of CTCs and cfDNA in the clinical aspects of cancer has become clear. With the development of next-generation sequencing analysis and newly developed technologies, many technical issues have been resolved, making liquid biopsy widely used in clinical practice. They can be powerful tools for dynamic monitoring of tumor progression and therapeutic efficacy. In the field of breast cancer, liquid biopsy is a research hot spot in recent years, playing a key role in monitoring breast cancer metastasis, predicting disease recurrence and assessing clinical drug resistance. Liquid biopsy has the advantages of noninvasive, high sensitivity, high specificity and real-time dynamic monitoring. Still application is far from reality, but the research and application prospects of CTCs and cfDNA in breast cancer are still worth exploring and discovering. This article reviews the main techniques and applications of CTCs and cfDNA in breast cancer.

Fluorescent microbeads for point-of-care testing: a review

Microbead-based point-of-care testing (POCT) has demonstrated great promise in translating detection modalities from bench-side to bed-side. This is due to the ease of visualization, high surface area-to-volume ratio of beads for efficient target binding, and efficient encoding capability for simultaneous detection of multiple analytes. This review (with 112 references) summarizes the progress made in the field of fluorescent microbead-based POCT. Following an introduction into the field, a first large section sums up techniques and materials for preparing microbeads, typically of dye-labelled particles, various kinds of quantum dots and upconversion materials. Further subsections cover the encapsulation of nanoparticles into microbeads, decoration of nanoparticles on microbeads, and in situ embedding of nanoparticles during microbead synthesis. A next large section summarizes microbead-based fluorometric POCT, with subsections on detection of nucleic acids, proteins, circulating tumor cells and bacteria. A further section covers emerging POCT based on the use of smartphones or flexible microchips. The last section gives conclusions and an outlook on current challenges and possible solutions. Aside from giving an overview on the state of the art, we expect this article to boost the further development of POCT technology. Graphical Abstract Schematic presentation of the fabrication of microbeads, the detection targets of interest including bacteria, circulating tumor cells (CTCs), protein and nucleic acid, and the emerging point-of-care testing (POCT) platform. The colored wheels of the bus represent the fluorescent materials embedded in (red color) or decorated on the surface of microbeads (green color).

Capture and "self-release" of circulating tumor cells using metal-organic framework materials

Capturing circulating tumor cells (CTCs) from peripheral blood for subsequent analyses has shown potential in precision medicine for cancer patients. Broad as the prospect is, there are still some challenges that hamper its clinical applications. One of the challenges is to maintain the viability of the captured cells during the capturing and releasing processes. Herein, we have described a composite material that could encapsulate a magnetic Fe3O4 core in a MIL-100 shell (MMs), which could respond to pH changes and modify the anti-EpCAM antibody (anti-EpCAM-MMs) on the surface of MIL-100. After the anti-EpCAM-MMs captured the cells, there was no need for additional conditions but with the acidic environment during the cell culture process, MIL-100 could realize automatic degradation, leading to cell self-release. This self-release model could not only improve the cell viability, but could also reduce the steps of the release process and save human and material resources simultaneously. In addition, we combined clinical patients' case diagnosis with the DNA sequencing and next generation of RNA sequencing technologies in the hope of precision medicine for patients in the future.

Bioinspired Engineering of a Multivalent Aptamer-Functionalized Nanointerface to Enhance the Capture and Release of Circulating Tumor Cells

Circulating tumor cell (CTC)-enrichment by using aptamers has a number of advantages, but the issue of compromised binding affinities and stabilities in real samples hinders its wide applications. Inspired by the high efficiency of the prey mechanism of the octopus, we engineered a deterministic lateral displacement (DLD)-patterned microfluidic chip modified with multivalent aptamer-functionalized nanospheres (AP-Octopus-Chip) to enhance capture efficiency. The multivalent aptamer-antigen binding efficiency improves 100-fold and the capture efficiency is enhanced more than 300 % compared with a monovalent aptamer-modified chip. Moreover, the captured cancer cells can be released through a thiol exchange reaction with up to 80 % efficiency and 96 % viability, which is fully compatible with downstream mutation detection and CTC culture. Using the chip, we were able to find CTCs in all cancer samples analyzed.