Multivalent Aptamer Functionalized Ag2S Nanodots/Hybrid Cell Membrane‐Coated Magnetic Nanobioprobe for the Ultrasensitive Isolation and Detection of Circulating Tumor Cells

Circulating tumor cells (CTCs) play key roles in the development of tumor metastasis. It remains a significant challenge to capture and detect CTCs with high purity and sensitivity from blood samples. Herein, a nanoplatform is developed for the efficient isolation and ultrasensitive detection of CTCs by combining near‐infrared (NIR) multivalent aptamer functionalized Ag₂S nanodots with hybrid cell membrane‐coated magnetic nanoparticles. Multivalent aptamer functionalized Ag₂S nanodots are synthesized using a one‐pot method under mild conditions (60 °C). White blood cell and tumor cell membranes are fused as the hybrid membrane and coated with magnetic nanoparticles, which are further modified with streptavidin (SA). Through the specific interaction of SA‐biotin, the multivalent aptamer‐Ag₂S nanodots are grafted with hybrid cell membrane‐magnetic nanoparticles. Due to the features of hybrid cell membrane modification, multivalent aptamer functionalization, magnetic separation, and NIR fluorescence measurements, the nanoplatform shows sensitive recognition, efficient capture, easy isolation, and sensitive detection of CTCs due to its great enhancement in anti‐interference from background and improvement on binding ability toward CTCs. The capture efficiency and purity for CTCs is as high as 97.63% and 96.96%, respectively. Furthermore, the nanoplatform is successfully applied to the detection of CTCs in blood samples.     

Platelet–Leukocyte Hybrid Membrane‐Coated Immunomagnetic Beads for Highly Efficient and Highly Specific Isolation of Circulating Tumor Cells

Biomimetic cell‐membrane‐camouflaged nanoparticles with desirable features have been widely used for various biomedical applications. However, the current research focuses on single cell membrane coating and using multiple cell membranes for nanoparticle functionalization is still challenging. In this work, platelet (PLT) and leukocyte (WBC) membranes are fused, PLT–WBC hybrid membranes are coated onto magnetic beads, and then their surface is modified with specific antibodies. The resulting PLT–WBC hybrid membrane‐coated immunomagnetic beads (HM‐IMBs) inherit enhanced cancer cell binding ability from PLTs and reduce homologous WBC interaction from WBCs, and are further used for highly efficient and highly specific isolation of circulating tumor cells (CTCs). By using spiked blood samples, it is found that, compared with commercial IMBs, the cell separation efficiency of HM‐IMBs is improved to 91.77% from 66.68% and the cell purity is improved to 96.98% from 66.53%. Furthermore, by using the HM‐IMBs, highly pure CTCs are successfully identified in 19 out of 20 clinical blood samples collected from breast cancer patients. Finally, the robustness of HM‐IMBs is verified in downstream CTC analysis such as the detection of PIK3CA gene mutations. It is anticipated that this novel hybrid membrane coating strategy will open new possibilities for overcoming the limitations of current theranostic platforms.     

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

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

Biospecific Monolayer Coating for Multivalent Capture of Circulating Tumor Cells with High Sensitivity

The isolation and detection of rare circulating tumor cells (CTCs) from patient peripheral blood can help to monitor the metastatic spread of carcinoma and evaluate therapeutic outcomes. However, it is technically challenging to isolate CTCs due to extreme rarity in blood. Current techniques typically have to utilize complex instrumentation to capture CTCs, resulting in nonapplicability. Inspired from the mussel adhesion, a polyglycerol‐based block polymer is used to fabricate a biospecific and bioinert interface for isolating CTCs with high selectivity and efficiency. Benefitting from the antifouling polyglycerol, the resulting monolayer coating greatly suppresses the nonspecific cells adhesion. Compared with one anti‐epithelial cell adhesion molecule (anti‐EpCAM), the CTCs' capture efficiency was improved to 95% when multiple receptors, i.e. anti‐EpCAM/Human epithelial receptor 2 (Her2)/Epithelial Growth Factor receptor (EGFR) are employed, even for low EpCAM‐expressing CTCs. The CTCs detection limit on the presented surface is as low as 1 cell mL^?1. Furthermore, CTCs are isolated from breast cancer patients' blood sample with a high selectivity. Also, the CTCs can be released and still keep proliferation capability for downstream analysis. This multifunctional block polymer surface coating is quite cost effective and highly applicable for CTCs' isolation in the clinic, which can provide a new prospect for designing the next‐generation of bio/nanointerfaces for biomedical studies.     

Microdevice for Separation of Circulating Tumor Cells Using Embedded Magnetophoresis with V‐shaped Ni‐Co Nanowires and Immuno‐nanomagnetic Beads

The novelty of this study resides in a 6”‐wafer‐level microfabrication protocol for a microdevice with a fluidic control system for the separation of circulating tumor cells (CTCs) from human whole blood cells. The microdevice utilizes a lateral magnetophoresis method based on immunomagnetic nanobeads with anti‐epithelial cell adhesive molecule antibodies that selectively bind to epithelial cancer cells. The device consists of a top polydimethylsiloxane substrate for microfluidic control and a bottom substrate for lateral magnetophoretic force generation with embedded v‐shaped soft magnetic microwires. The microdevice can isolate about 93% of the spiked cancer cells (MCF‐7, a breast cancer cell line) at a flow rate of 40/100 mL/min with respect to a whole human blood/buffer solution. For all isolation, it takes only 10 min to process 400 mL of whole human blood. The fabrication method is sufficiently simple and easy, allowing the microdevice to be a mass‐producible clinical tool for cancer diagnosis, prognosis, and personalized medicine.     

Hybrid Monoliths for Magnetically‐Driven Protein Separations

Monoliths represent powerful platforms for isolation of large molecules with high added value. This work presents a hybrid approach for antibody (Ab) capture and release. Using mostly natural polymers and clean processes, it is possible to create macroporous monoliths with well‐defined porous networks, tuneable mechanical properties, and easy functionalization with a biomimetic ligand specific for Ab. Magnetic nanoparticles (MNPs) are embedded on the monolith network to confer a controlled magnetic response that facilitates and accelerates Ab recovery in the elution step. The hybrid monolithic systems prepared with agarose or chitosan/poly(vinyl alcohol) (PVA) blends exhibit promising binding capacities of Abs directly from cell‐culture extracts (120 ± 10 mg Ab g^?1 support) and controlled Ab magnetically‐assisted elution yielding 95 ± 2% recovery. Moreover, a selective capture of mAbs directly from cell culture extracts is achieved yielding a final mAb preparation with 96% of purity.     

Activated Platelets‐Targeting Micelles with Controlled Drug Release for Effective Treatment of Primary and Metastatic Triple Negative Breast Cancer

The frequent relapse and metastasis characteristics of triple negative breast cancer (TNBC) make it a fraught issue with very poor prognosis in clinic. An effective treatment for TNBC should prevent and even eliminate metastasis as well as suppress primary lesion expansion. Recent progress reveals that platelets can be recruited and activated by tumor cells through intercellular adhesion molecules (ICAM), and help aggressive circulating tumor cells (CTCs) form metastasis. Therefore, activated platelets are considered with possession of tumor‐homing, CTC‐capturing, and metastasis‐targeting abilities. In this work, a P‐selectin (expressed on activated platelet surface) targeting peptide (PSN) is modified on a redox‐responsive paclitaxel‐loaded micelle (PSN‐PEG‐SS‐PTX₄ micelle) to utilize activated platelets as a “bridge” for interaction with cancer cells. The PSN‐modified micelle can easily adhere to the surface of activated platelets and subsequently capture CTCs in blood circulation. Compared to Taxol and PEG‐SS‐PTX₄ micelle, PSN‐PEG‐SS‐PTX₄ micelle also exhibits enhanced primary TNBC/metastasis targeting and penetrating effect through binding with tumor infiltrating platelets and thus significantly improves treatment outcome. More importantly, PSN‐PEG‐SS‐PTX₄ micelle potently suppressed lung metastasis of TNBC and reduced incidence of distant liver metastasis. The activated platelet‐targeting redox‐responsive micelle system provides a promising prospect for the omnidirectional treatment of metastatic cancer.     

Targeting of CXCR1 on Osteosarcoma Circulating Tumor Cells and Precise Treatment via Cisplatin Nanodelivery

Metastasis and chemotherapy resistance are the key factors affecting the effectiveness of osteosarcoma (OS) treatments. CXCR1 overexpression is found to be closely related to chemotherapy resistance and anoikis resistance in OS cell subtypes with high metastasis potential. Further study demonstrates that CXCR1 is highly expressed on circulating tumor cell (CTC)‐derived cells with cancer stem cell characteristics. Then, a CXCR1 targeting peptide is designed and synthesized to competitively inhibit the IL‐8/CXCR1 pathway and to improve the cisplatin sensitivity of CTCs. Fluorescence‐labeled magnetic nanoparticles (NPs) with pH‐responsive cisplatin release are fabricated and linked with the CXCR1 targeting peptide (Cis@MFPPC). Results demonstrate that CTC survival could be inhibited effectively by the targeting nanoparticles in vivo. Cis@MFPPC can also inhibit OS growth and pulmonary metastasis in an orthotopic model and patient‐derived tumor xenograft model. This study verifies the clinical significance of CXCR1 as a therapeutic target and provides a drug delivery NP system for precise treatment of OS.     

细胞捕获的微流控芯片及自动化细胞计数方法

介绍了一种新型的基于免疫磁珠分选法的外周血循环肿瘤细胞(circulate tumor cell,CTC)捕捉芯片的制作方法,使得芯片的磁性微柱和流道可以同步成型,简化了制作流程,弥补了传统电铸工艺难以稳定实现高深宽比结构的不足,适应性和扩展性都比较好。同时针对人结肠癌培养细胞,结合图像处理技术,对细胞荧光图像进行了细胞的自动分割和计数,实现了一个细胞捕获和分析自动化系统,从而极大地提高了CTC检测的效率。主要研究了细胞捕获芯片的制作和图像处理的方法等。结果表明该细胞捕获分析系统可以给出较好的细胞捕获和计数结果,从而显著提高工作效率。     

Gradient Magnetic Separation and Fluorescent Imaging-Based Heterogeneous Circulating Tumor Cell Subpopulations Assay with Biomimetic Multifunctional Nanoprobes

The heterogeneity of circulating tumor cells (CTCs) greatly impacts cancer metastasis and malignancy, contributing to increased mortality. Therefore, the analysis of such heterogeneity is essential to clinical diagnosis, treatment, and monitoring of patients. Though varied, the types and expression levels of proteins on heterogeneous CTCs enable specific recognition and separation. Accordingly, herein the sequential magnetic separation and fluorescence visualization-based assay of heterogeneous CTCs after the model tumor cells of BT474^Her2+++, LNCaP^PSMA++, and MDA-MB-231^Vim+ binding with corresponding antibody-modified biomimetic fluorescent-magnetic nanoprobes with different magnetic sensitivities is reported. These nanoprobes-bound cell subpopulations are specifically recognized and magnetically separated at different time points under an external magnetic field with good capture performance within several minutes. Moreover, a low detection limit of 1 cell mL⁻¹ in blood sample could be achieved. Consequently, the as-proposed strategy based on gradient magnetic separation, fluorescent imaging, and biomimetic membrane, shows promise for clinical applications.     

Enhanced Specificity in Capturing and Restraining Circulating Tumor Cells with Dual Antibody–Dendrimer Conjugates

Specifically capturing and restraining residual circulating tumor cells (CTCs) in cancer patients are the sine qua non for safely and effectively preventing cancer metastasis, to which the current chemotherapy has been limited due to its toxicity. Moreover, because of CTCs’ rarity and low activity, the current technology for capturing CTCs based solely on a single surface biomarker has limited capacity and is used mainly for in vitro diagnosis. Here, it is possible to sequentially conjugate two CTCs antibodies (aEpCAM and aSlex) to the functionalized dendrimers to specifically capture human hepatocellular CTCs in both artificial and clinical patient blood samples, and restrain their activities. The molecular entities of the conjugates are demonstrated by various means. The dual antibody conjugate captured CTCs threefold more than the single counterparts from the high concentrations of interfering red blood cells or leukocytes, as well as from the blood of liver cancer patients, and exhibits the superiority to their single counterparts in down‐regulating the captured CTCs. These results collectively provide the strong evidence that two antibodies can be compatibly conjugated to a nanomaterial, resulting in an enhanced specificity in restraining CTCs in blood.     

Ultrasensitive,Biocompatible, Quantum‐Dot‐Embedded Silica Nanoparticles for Bioimaging

The successful development of highly sensitive, water‐compatible, nontoxic nanoprobes has allowed nanomaterials to be widely employed in various applications. The applicability of highly bright quantum dot (QD)‐based probes consisting of QDs on 120 nm silica nanoparticles (NPs) with silica shells is investigated. Their substantial merits, such as their brightness and biocompatibility, for effective bioimaging are demonstrated. Silica‐coated, QD‐embedded silica NPs (Si@QDs@Si NPs) containing QDs composed of CdSe@ZnS (core‐shell) are prepared to compare their structure‐based advantages over single QDs that have a similar quantum yield (QY). These Si@QDs@Si NPs exhibit approximately 200‐times stronger photoluminescence (PL) than single QDs. Cytotoxicity studies reveal that the Si@QDs@Si NPs are less toxic than equivalent numbers of silica‐free single quantum dots. The excellence of the Si@QDs@Si NPs with regard to in vivo applications is illustrated by significantly enhanced fluorescence signals from Si@QDs@Si‐NP‐tagged cells implanted in mice. Notably, a more advanced version of QD‐based silica NPs (Si@mQDs@Si NPs), containing multishell quantum dots (mQDs) composed of CdSe@CdS@ZnS, are prepared without significant loss of QY during surface modification. In addition, the Si@mQDs@Si NPs display a fivefold higher fluorescence activity than the Si@QDs@Si NPs. As few as 400 units of Si@mQDs@Si‐ NP‐internalized cells can be detected in the cell‐implanted mouse model.     

Ultrasensitive Telomerase Activity Detection in Circulating Tumor Cells Based on DNA Metallization and Sharp Solid‐State Electrochemical Techniques

Being considered a “liquid biopsy”, circulating tumor cell (CTC) quantification is of great interest for evaluating cancer dissemination, predicting patient prognosis, and also for the evaluation of therapeutic treatments, representing a reliable potential alternative to invasive biopsies and subsequent proteomic and functional genetic analysis. Compared to a biopsy, the gold standard of current cancer diagnosis, an important characteristic of a blood test is that it is safe and can be performed at many points during the disease, allowing the development of appropriate therapy modifications and potentially improving patient's quality of life. In this work, an ultrasensitive electrochemical telomerase activity‐sensing strategy is presented that utilizes DNA‐templated deposition of silver nanoparticles as electroactive labels through a highly sharp solid‐state Ag/AgCl reaction with DNA exonuclease III‐assisted background current suppression. This nanoparticle‐mediated signal amplification resulted in significantly decreased detection limit, which is better than the vast majority of reported methods and achieves a sensitivity comparable to the conventional telomeric repeat amplification protocol (TRAP). This work may pave a new PCR‐free way for the detection of telomerase activity in CTCs via a noninvasive routine blood test for point‐of‐care diagnosis and individualized treatment of cancer.     

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality ZnxCd1‐xS/ZnS Core/Shell Quantum Dots

High‐quality violet‐blue emitting Zn_xCd_1‐xS/ZnS core/shell quantum dots (QDs) are synthesized by a new method, called “nucleation at low temperature/shell growth at high temperature”. The resulting nearly monodisperse Zn_xCd_1‐xS/ZnS core/shell QDs have high PL quantum yield (near to 100%), high color purity (FWHM) <25 nm), good color tunability in the violet‐blue optical window from 400 to 470 nm, and good chemical/photochemical stability. More importantly, the new well‐established protocols are easy to apply to large‐scale synthesis; around 37 g Zn_xCd_1‐xS/ZnS core/shell QDs can be easily synthesized in one batch reaction. Highly efficient deep‐blue quantum dot‐based light‐emitting diodes (QD‐LEDs) are demonstrated by employing the Zn_xCd_1‐xS/ZnS core/shell QDs as emitters. The bright and efficient QD‐LEDs show a maximum luminance up to 4100 cd m^?2, and peak external quantum efficiency (EQE) of 3.8%, corresponding to 1.13 cd A^?1 in luminous efficiency. Such high value of the peak EQE can be comparable with OLED technology. These results signify a remarkable progress, not only in the synthesis of high‐quality QDs but also in QD‐LEDs that offer a practicle platform for the realization of QD‐based violet‐blue display and lighting.     

Morphology Controlled Poly(aminophenylboronic acid) Nanostructures as Smart Substrates for Enhanced Capture and Release of Circulating Tumor Cells

A strategy is proposed to achieve an enhanced capture efficiency of and low damage to human leukemic lymphoblasts (CCRF‐CEM) by the synergistic effect of topographical interactions and phenylboronic acid functional groups on nanostructures. To realize this purpose, a simple and template free method to synthesize boronic acid derivative polyaniline bioinspired nanostructures with controlled morphology is established. Different nanostructured morphologies such as nanotexture, nanofibers, nanoparticles, microsphere, and 3D porous network have been prepared by controlling the nucleation and growth rate for polymerization. The phenylboronic acid functional groups on the surface of the nanostructures during poly­merization are used as artificial lectins to reversibly capture and release circulating tumor cells (CTCs) with little damage to the cells. The method presented here is simple, rapid, and highly efficient for CTC capture and release with low cost in materials and instruments.     

Light‐Emitting Electrochemical Cells Based on Color‐Tunable Inorganic Colloidal Quantum Dots

Large‐area, ultrathin light‐emitting devices currently inspire architects and interior and automotive designers all over the world. Light‐emitting electrochemical cells (LECs) and quantum dot light‐emitting diodes (QD‐LEDs) belong to the most promising next‐generation device concepts for future flexible and large‐area lighting technologies. Both concepts incorporate solution‐based fabrication techniques, which makes them attractive for low cost applications based on, for example, roll‐to‐roll fabrication or inkjet printing. However, both concepts have unique benefits that justify their appeal. LECs comprise ionic species in the active layer, which leads to the omission of additional organic charge injection and transport layers and reactive cathode materials, thus LECs impress with their simple device architecture. QD‐LEDs impress with purity and opulence of available colors: colloidal quantum dots (QDs) are semiconducting nanocrystals that show high yield light emission, which can be easily tuned over the whole visible spectrum by material composition and size. Emerging technologies that unite the potential of both concepts (LEC and QD‐LED) are covered, either by extending a typical LEC architecture with additional QDs, or by replacing the entire organic LEC emitter with QDs or perovskite nanocrystals, still keeping the easy LEC setup featured by the incorporation of mobile ions.     

Immobilization of Quantum Dots in Nanostructured Porous Silicon Films: Characterizations and Signal Amplification for Dual‐Mode Optical Biosensing

Highly sensitive dual‐mode labeled detection of biotin in well‐characterized porous silicon (PSi) films using colloidal quantum dots (QDs) as signal amplifiers are demonstrated. Optimization of the PSi platform for targeted QD infiltration and immobilization is carried out by characterizing and tuning the porosity, film depth, and pore size. Binding events of target QD‐biotin conjugates with streptavidin probes immobilized on the pore walls are monitored by reflective interferometric spectroscopy and fluorescence measurements. QD labeling of the target biotin molecules enables detection based on a distinct fluorescent signal as well as a greater than 5‐fold enhancement in the measured spectral reflectance fringe shift and a nearly three order of magnitude improvement in the detection limit for only 6% surface area coverage of QDs inside the porous matrix. Utilizing the QD signal amplifiers, an exceptional biotin detection limit of ≈6 fg mm^?2 is demonstrated with sub‐fg mm^?2 detection limits achievable.     

Engineered Microneedles for Interstitial Fluid Cell‐Free DNA Capture and Sensing Using Iontophoretic Dual‐Extraction Wearable Patch

Interstitial fluid (ISF), as an emerging source of biomarkers, is unmistakably significant for disease diagnosis. Microneedles (MNs) provide a minimally invasive approach for extracting the desired molecules from ISF. However, existing MNs are limited by their capture efficiency and sensitivity, which impedes early disease diagnosis. Herein, an engineered wearable epidermal system is presented with a combination of reverse iontophoresis and MNs for rapid capture and sensing of Epstein‐Barr virus cell‐free DNA (an important biomarker of nasopharyngeal carcinoma). Owing to a dual‐extraction effect demonstrated by reverse iontophoresis and MNs, the engineered wearable platform successfully isolates the cell‐free DNA target from ISF within 10 min, with a threshold of 5 copies per µL and a maximum capture efficiency of 95.4%. The captured cell‐free DNA is also directly used in a recombinase polymerase amplification electrochemical microfluidic biosensor with a detection limit of 1.1 copies per µL (or a single copy). The experimental data from immunodeficient mouse models rationalizes the feasibility and practicality of the wearable system. Collectively, the developed method opens an innovative route for minimally invasive sampling of ISF for cell‐free DNA‐related cancer screening and prognosis.     

Self‐Assembled InAs Quantum Dots on InP(001) for Long‐Wavelength Laser Applications

Self‐assembled InAs quantum dots (QDs) embedded in an InAlGaAs matrix were grown on an InP (001) using a solid‐source molecular beam epitaxy and investigated using transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. TEM images indicated that the QD formation was strongly dependent on the growth behaviors of group III elements during the deposition of InAlGaAs barriers. We achieved a lasing operation of around 1.5 µm at room temperature from uncoated QD lasers based on the InAlGaAs‐InAlAs material system on the InP (001). The lasing wavelengths of the ridge‐waveguide QD lasers were also dependent upon the cavity lengths due mainly to the gain required for the lasing operation.     

Effect of CdSe/ZnS quantum dots on color purity and electrical properties of polyfluorene based hybrid light emitting diode

We report enhanced color purity of hybrid organic-inorganic light emitting diode based on polyfluorene-CdSe/ZnS quanum dot (QD) blend as emissive layer. Effect on structural, optical and electrical properties of different doping concentration (0–100 wt.%) of QD in polyfluorene (PFO) was studied. Photoluminescence and electroluminescence spectra confirm the β-formation of PFO by incorporation of CdSe/ZnS QD. Photoluminescence (PL) of blend film was also compared with another method based on one dimensional photonic band gap (1D-PBG) structure that has been used for color purity. In both the cases, that is, QD doped device and 1D-PBG based structures the narrowing of PL spectra was observed. But the fabrication of QD-doped device for color purity is easier than fabricating 1D-PBG structure using multilayer dielectric coating. The present study might find application for QD based color displays, where color purity is an important requirement.