Detecting circulating tumor cells: current challenges and new trends

Dual targeting negative enrichment strategy for highly sensitive and purity detection of CTCs

Circulating tumor cells (CTCs) have significant clinical value in early tumor detection, dynamic monitoring and immunotherapy. CTC detection stands out as a leading non-invasive approach for tumor diagnostics and therapeutics. However, the high heterogeneity of CTCs and the occurrence of epithelial-mesenchymal transition (EMT) during metastasis pose challenges to methods relying on EpCAM-positive enrichment. To address these limitations, a method based on negative enrichment of CTCs using specific leukocyte targets has been developed. In this study, aiming to overcome the low purity associated with immunomagnetic beads targeting solely the leukocyte common antigen CD45, we introduced CD66b-modified immunomagnetic beads. CD66b, a specific target for neutrophils with abundant residues, was chosen as a complementary approach. The process involved initial collection of nucleated cells from whole blood samples using density gradient centrifugation. Subsequently, magnetically labeled leukocytes were removed by magnetic field, enabling the capture of CTCs with higher sensitivity and purity while retaining their activity. Finally, we selected 20 clinical blood samples from patients with various cancers to validate the effectiveness of this strategy, providing a new generalized tool for the clinical detection of CTCs.

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).

Clinical Application of Different Liquid Biopsy Components in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, usually occurring in the background of chronic liver disease. HCC lethality rate is in the third highest place in the world. Patients with HCC have concealed early symptoms and possess a high-level of heterogeneity. Once diagnosed, most of the tumors are in advanced stages and have a poor prognosis. The sensitivity and specificity of existing detection modalities and protocols are suboptimal. HCC calls for more sophisticated and individualized therapeutic regimens. Liquid biopsy is non-invasive, repeatable, unaffected by location, and can be monitored dynamically. It has emerged as a useable aid in achieving precision malignant tumor treatment. Circulating tumor cells (CTCs), circulating nucleic acids, exosomes and tumor-educated platelets are the commonest components of a liquid biopsy. It possesses the theoretical ability to conquer the high heterogeneity and the difficulty of early detection for HCC patients. In this review, we summarize the common enrichment techniques and the clinical applications in HCC for different liquid biopsy components. Tumor recurrence after HCC-related liver transplantation is more insidious and difficult to treat. The clinical use of liquid biopsy in HCC-related liver transplantation is also summarized in this review.

A photoelectrochemical aptasensor based on double Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction for sensitive detection of circulating tumor cells

A novel photoelectrochemical (PEC) aptasensor based on a dual Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction for the ultrasensitive detection of circulating tumor cells (CTCs) was developed. The α-Fe2O3/MoS2/Bi2S3 nanocomposite was prepared via a step-by-step route, and the photoproduced electron/hole transfer path was speculated by conducting trapping experiments of reactive species. α-Fe2O3/MoS2/Bi2S3-modified electrodes exhibited greatly enhanced photocurrent under visible light due to the double Z-scheme charge transfer process, which met the requirement of the PEC sensor for detecting larger targets. After the aptamer was conjugated on the photoelectrode through chitosan (CS) and glutaraldehyde (GA), when MCF-7 cells were presented and captured, the photocurrent of the PEC biosensing system decreased due to steric hindrance. The current intensity had a linear relationship with the logarithm of MCF-7 cell concentration ranging from 10 to 1×105 cells mL-1, with a low detection limit of 3 cell mL-1 (S/N = 3). The dual Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction-modified PEC aptasensor exhibited high sensitivity and excellent specificity and stability. Additionally, MCF-7 cells in human serum were determined by this PEC aptasensor, exhibiting great potential as a promising tool for clinical detection.

Ultrahigh-Throughput, Real-Time Flow Cytometry for Rare Cell Quantification from Whole Blood

We present an ultrahigh-throughput, real-time fluorescence cytometer comprising a viscoelastic microfluidic system and a complementary metal-oxide-semiconductor (CMOS) linear image sensor-based detection system. The flow cytometer allows for real-time quantification of a variety of fluorescence species, including micrometer-sized particles and cells, at analytical throughputs in excess of 400,000 species per second. The platform integrates a custom C++ control program and graphical user interface (GUI) to allow for the processing of raw signals, adjustment of processing parameters, and display of fluorescence intensity histograms in real time. To demonstrate the efficacy of the platform for rare event detection and its utility as a basic clinical tool, we measure and quantify patient-derived circulating tumor cells (CTCs) in peripheral blood, realizing that detection has a sensitivity of 6 CTCs per million blood cells (0.000006%) with a volumetric throughput of over 3 mL/min.

Metabolic Glycoengineering-Programmed Nondestructive Capture of Circulating Tumor Cells

Circulating tumor cells (CTCs) are the "seeds" for malignant tumor metastasis, and they serve as an ideal target for minimally invasive tumor diagnosis. Abnormal glycolysis in tumor cells, characterized by glycometabolism disorder, has been reported as a universal phenomenon observed in various types of tumors. This provides a potential powerful tool for universal CTC capture. However, to the best of our knowledge, no metabolic glycoengineering-based CTC capture strategies have been reported. Here, we proposed a nondestructive CTC capture method based on metabolic glycoengineering and a nanotechnology-based proximity effect, allowing for highly specific, sensitive, and universal CTC capture. To achieve this goal, cells are first labeled with DNA tags through metabolic glycoengineering and then captured through a DNA tetrahedra-functionalized dual-tentacle magnetic nanodevice. Due to the difference in metabolic performance, only tumor cells are labeled with more densely packed DNA tags and captured through enhanced intermolecular interaction mediated by the proximity effect. In summary, we have constructed a versatile platform for nondestructive CTC capture, offering a novel perspective for the application of CTC liquid biopsy in tumor diagnosis and treatment.

The Utilization of Optically Induced Dielectrophoresis (ODEP)-Based Cell Manipulation in a Microfluidic System for the Purification and Sorting of Circulating Tumor Cells (CTCs) with Different Sizes

The analysis of circulating tumor cells (CTCs) at the molecular level holds great promise for several clinical applications. For this goal, the harvest of high-purity, size-sorted CTCs with different subtypes from a blood sample are important. For this purpose, a two-step CTC isolation protocol was proposed, by which the immunomagnetic beads-based cell separation was first utilized to remove the majority of blood cells. After that, an optically induced dielectrophoresis (ODEP) microfluidic system was developed to (1) purify the CTCs from the remaining magnetic microbeads-bound blood cells and to (2) sort and separate the CTCs with different sizes. In this study, the ODEP microfluidic system was designed and fabricated. Moreover, its optimum operation conditions and performance were explored. The results exhibited that the presented technique was able to purify and sort the cancer cells with two different sizes from a tested cell suspension in a high-purity (93.5% and 90.1% for the OECM 1 and HA22T cancer cells, respectively) manner. Overall, this study presented a technique for the purification and sorting of cancer cells with different sizes. Apart from this application, the technique is also useful for other applications in which the high-purity and label-free purification and sorting of cells with different sizes is required.

Study on the detection method of biological characteristics of hepatoma cells based on terahertz time-domain spectroscopy

Liver cancer usually has a high degree of malignancy and its early symptoms are hidden, therefore, it is of significant research value to develop early-stage detection methods of liver cancer for pathological screening. In this paper, a biometric detection method for living human hepatocytes based on terahertz time-domain spectroscopy was proposed. The difference in terahertz response between normal and cancer cells was analyzed, including five characteristic parameters in the response, namely refractive index, absorption coefficient, dielectric constant, dielectric loss and dielectric loss tangent. Based on class separability and variable correlation, absorption coefficient and dielectric loss were selected to better characterize cellular properties. Maximum information coefficient and principal component analysis were employed for feature extraction, and a cell classification model of support vector machine was constructed. The results showed that the algorithm based on parameter feature fusion can achieve an accuracy of 91.6% for human hepatoma cell lines and one normal cell line. This work provides a promising solution for the qualitative evaluation of living cells in liquid environment.

Giant Magnetoresistance Based Biosensors for Cancer Screening and Detection

Early-stage screening of cancer is critical in preventing its development and therefore can improve the prognosis of the disease. One accurate and effective method of cancer screening is using high sensitivity biosensors to detect optically, chemically, or magnetically labeled cancer biomarkers. Among a wide range of biosensors, giant magnetoresistance (GMR) based devices offer high sensitivity, low background noise, robustness, and low cost. With state-of-the-art micro- and nanofabrication techniques, tens to hundreds of independently working GMR biosensors can be integrated into fingernail-sized chips for the simultaneous detection of multiple cancer biomarkers (i.e., multiplexed assay). Meanwhile, the miniaturization of GMR chips makes them able to be integrated into point-of-care (POC) devices. In this review, we first introduce three types of GMR biosensors in terms of their structures and physics, followed by a discussion on fabrication techniques for those sensors. In order to achieve target cancer biomarker detection, the GMR biosensor surface needs to be subjected to biological decoration. Thus, commonly used methods for surface functionalization are also reviewed. The robustness of GMR-based biosensors in cancer detection has been demonstrated by multiple research groups worldwide and we review some representative examples. At the end of this review, the challenges and future development prospects of GMR biosensor platforms are commented on. With all their benefits and opportunities, it can be foreseen that GMR biosensor platforms will transition from a promising candidate to a robust product for cancer screening in the near future.

Smartphone Imaging Flow Cytometry for High-Throughput Single-Cell Analysis

We present a portable imaging flow cytometer comprising a smartphone, a small-footprint optical framework, and a PDMS-based microfluidic device. Flow cytometric analysis is performed in a sheathless manner via elasto-inertial focusing with a custom-written Android program, integrating a graphical user interface (GUI) that provides a high degree of user control over image acquisition. The proposed system offers two different operational modes. First, "post-processing" mode enables particle/cell sizing at throughputs of up to 67 000 particles/s. Alternatively, "real-time" mode allows for integrated cell/particle classification with machine learning at throughputs of 100 particles/s. To showcase the efficacy of our platform, polystyrene particles are accurately enumerated within heterogeneous populations using the post-processing mode. In real-time mode, an open-source machine learning algorithm is deployed within a custom-developed Android application to classify samples containing cells of similar size but with different morphologies. The flow cytometer can extract high-resolution bright-field images with a spatial resolution <700 nm using the developed machine learning-based algorithm, achieving classification accuracies of 97% and 93% for Jurkat and EL4 cells, respectively. Our results confirm that the smartphone imaging flow cytometer (sIFC) is capable of both enumerating single particles in flow and identifying morphological features with high resolution and minimal hardware.

Development and clinical validation of a microfluidic-based platform for CTC enrichment and downstream molecular analysis

Background

Although many CTC isolation and detection methods can provide information on cancer cell counts, downstream gene and protein analysis remain incomplete. Therefore, it is crucial to develop a technology that can provide comprehensive information on both the number and profile of CTC.

Methods

In this study, we developed a novel microfluidics-based CTC separation and enrichment platform that provided detailed information about CTC.

Results

This platform exhibits exceptional functionality, achieving high rates of CTC recovery (87.1%) and purification (∼4 log depletion of WBCs), as well as accurate detection (95.10%), providing intact and viable CTCs for downstream analysis. This platform enables successful separation and enrichment of CTCs from a 4 mL whole-blood sample within 15 minutes. Additionally, CTC subtypes, selected protein expression levels on the CTC surface, and target mutations in selected genes can be directly analyzed for clinical utility using immunofluorescence and real-time polymerase chain reaction, and the detected PD-L1 expression in CTCs is consistent with immunohistochemical assay results.

Conclusion

The microfluidic-based CTC enrichment platform and downstream molecular analysis together provide a possible alternative to tissue biopsy for precision cancer management, especially for patients whose tissue biopsies are unavailable.

Diverse applications and development of aptamer detection technology

Aptamers have received extensive attention in recent years because of their advantages of high specificity, high sensitivity and low immunogenicity. Aptamers can perform almost all functions of antibodies through the combination of spatial structure and target, which are called "chemical antibodies". At present, aptamers have been widely used in cell imaging, new drug development, disease treatment, microbial detection and other fields. Due to the diversity of modifications, aptamers can be combined with different detection technologies to construct aptasensors. This review focuses on the diversity of aptamers in the field of detection and the development of aptamer-based detection technology and proposes new challenges for aptamers in this field.

Circulating Tumor Cells as a Promising Tool for Early Detection of Hepatocellular Carcinoma

Liver cancer is a significant contributor to the cancer burden, and its incidence rates have recently increased in almost all countries. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and is the second leading cause of cancer-related deaths worldwide. Because of the late diagnosis and lack of efficient therapeutic modality for advanced stages of HCC, the death rate continues to increase by ~2-3% per year. Circulating tumor cells (CTCs) are promising tools for early diagnosis, precise prognosis, and follow-up of therapeutic responses. They can be considered to be an innovative biomarker for the early detection of tumors and targeted molecular therapy. In this review, we briefly discuss the novel materials and technologies applied for the practical isolation and detection of CTCs in HCC. Also, the clinical value of CTC detection in HCC is highlighted.

CTC, ctDNA, and Exosome in Thyroid Cancers: A Review

Thyroid cancer has become more common in recent years all around the world. Many issues still need to be urgently addressed in the diagnosis, treatment, and prognosis of thyroid cancer. Liquid biopsy (mainly circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and circulating exosomes) may provide a novel and ideal approach to solve these issues, allows us to assess the features of diseases more comprehensively, and has a function in a variety of malignancies. Recently, liquid biopsy has been shown to be critical in thyroid cancer diagnosis, treatment, and prognosis in numerous previous studies. In this review, by testing CTCs, ctDNA, and exosomes, we focus on the possible clinical role of liquid biopsy in thyroid cancer, including diagnostic and prognostic biomarkers and response to therapy. We briefly review how liquid biopsy components have progressed in thyroid cancer by consulting the existing public information. We also discuss the clinical potential of liquid biopsy in thyroid cancer and provide a reference for liquid biopsy research. Liquid biopsy has the potential to be a useful tool in the early detection, monitoring, or prediction of response to therapies and prognosis in thyroid cancer, with promising clinical applications.

Liquid Biopsy in Hepatocellular Carcinoma: The Significance of Circulating Tumor Cells in Diagnosis, Prognosis, and Treatment Monitoring

Hepatocellular carcinoma (HCC) is an aggressive malignancy with poor outcomes when diagnosed at an advanced stage. Current curative treatments are most effective in early-stage HCC, highlighting the importance of early diagnosis and intervention. However, existing diagnostic methods, such as radiological imaging, alpha-fetoprotein (AFP) testing, and biopsy, have limitations that hinder early diagnosis. AFP elevation is absent in a significant portion of tumors, and imaging may have low sensitivity for smaller tumors or in the presence of cirrhosis. Additionally, as our understanding of the molecular pathogenesis of HCC grows, there is an increasing need for molecular information about the tumors. Biopsy, although informative, is invasive and may not always be feasible depending on tumor location. In this context, liquid biopsy technology has emerged as a promising approach for early diagnosis, enabling molecular characterization and genetic profiling of tumors. This technique involves analyzing circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), or tumor-derived exosomes. CTCs are cancer cells shed from the primary tumor or metastatic sites and circulate in the bloodstream. Their presence not only allows for early detection but also provides insights into tumor metastasis and recurrence. By detecting CTCs in peripheral blood, real-time tumor-related information at the DNA, RNA, and protein levels can be obtained. This article provides an overview of CTCs and explores their clinical significance for early detection, prognosis, treatment selection, and monitoring treatment response in HCC, citing relevant literature.

The sound of blood: photoacoustic imaging in blood analysis

Blood analysis is a ubiquitous and critical aspect of modern medicine. Analyzing blood samples requires invasive techniques, various testing systems, and samples are limited to relatively small volumes. Photoacoustic imaging (PAI) is a novel imaging modality that utilizes non-ionizing energy that shows promise as an alternative to current methods. This paper seeks to review current applications of PAI in blood analysis for clinical use. Furthermore, we discuss obstacles to implementation and future directions to overcome these challenges. Firstly, we discuss three applications to cellular analysis of blood: sickle cell, bacteria, and circulating tumor cell detection. We then discuss applications to the analysis of blood plasma, including glucose detection and anticoagulation quantification. As such, we hope this article will serve as inspiration for PAI's potential application in blood analysis and prompt further studies to ultimately implement PAI into clinical practice.

Rapid detection of EGFR mutation in CTCs based on a double spiral microfluidic chip and the real-time RPA method

Circulating tumor cells (CTCs) are cells shed from primary or metastatic tumors and spread into the peripheral bloodstream. Mutation detection in CTCs can reveal vital genetic information about the tumors and can be used for "liquid biopsy" to indicate cancer treatment and targeted medication. However, current methods to measure the mutations in CTCs are based on PCR or DNA sequencing which are cumbersome and time-consuming and require sophisticated equipment. These largely limited their applications especially in areas with poor healthcare infrastructure. Here we report a simple, convenient, and rapid method for mutation detection in CTCs, including an example of a deletion at exon 19 (Del19) of the epidermal growth factor receptor (EGFR). CTCs in the peripheral blood of NSCLC patients were first sorted by a double spiral microfluidic chip with high sorting efficiency and purity. The sorted cells were then lysed by proteinase K, and the E19del mutation was detected via real-time recombinase polymerase amplification (RPA). Combining the advantages of microfluidic sorting and real-time RPA, an accurate mutation determination was realized within 2 h without professional operation or complex data interpretation. The method detected as few as 3 cells and 1% target variants under a strongly interfering background, thus, indicating its great potential in the non-invasive diagnosis of E19del mutation for NSCLC patients. The method can be further extended by redesigning the primers and probes to detect other deletion mutations, insertion mutations, and fusion genes. It is expected to be a universal molecular diagnostic tool for real-time assessment of relevant mutations and precise adjustments in the care of oncology patients.

Endometrial telomerase activity in women with either endometrial cancer or hyperplasia: A systematic review and meta-analysis

AIM

We performed a systematic review and meta-analysis to assess whether endometrial telomerase activity is associated with endometrial cancer or hyperplasia.

METHODS

PubMed, Web of Science, Embase, Scielo, LILAC, and CNKI databases were searched to obtain relevant literature for articles published through June 2022, following PRISMA guidelines and a registered PROSPERO protocol. We included observational studies reporting endometrial telomerase activity in patients with either endometrial cancer or hyperplasia compared with benign endometrial tissue (control women). The Newcastle-Ottawa Scale was used to evaluate the quality of studies. Data were expressed as the odds ratios (OR) and 95 % confidence intervals (CI). Random effects and inverse variance methods were used to meta-analyze associations. The I² test was used to assess heterogeneity.

RESULTS

There were significant associations between endometrial telomerase activity and either endometrial cancer (20 studies, OR = 10.65, 95 % CI 6.39, 17.75, p = 0.00001, I² = 21 %) or endometrial hyperplasia (nine studies, OR = 3.62, 95 % CI 1.61, 8.13, p = 0.002, I² = 36 %) compared to women without endometrial cancer and hyperplasia. There was not a significant difference in telomerase activity in women with endometrial cancer compared to those with endometrial hyperplasia (seven studies, OR = 1.03; 95 % CI 0.31, 3.37, p = 0.96, I² = 49 %). In subgroup analyses, there were no significant differences in telomerase activity in patients with endometrial cancer by type of observational studies and by countries of the studies.

CONCLUSION

Endometrial telomerase activity is higher in women with either endometrial cancer or endometrial hyperplasia compared to control women without those lesions.

Bowel Preparation for Colonoscopy Changes Serum Composition as Detected by Thermal Liquid Biopsy and Fluorescence Spectroscopy

(1) Background: About 50% of prescribed colonoscopies report no pathological findings. A secondary screening test after fecal immunochemical test positivity (FIT+) would be required. Considering thermal liquid biopsy (TLB) as a potential secondary test, the aim of this work was to study possible interferences of colonoscopy bowel preparation on TLB outcome on a retrospective study; (2) Methods: Three groups were studied: 1/514 FIT(+) patients enrolled in a colorectal screening program (CN and CP with normal and pathological colonoscopy, respectively), with blood samples obtained just before colonoscopy and after bowel preparation; 2/55 patients from the CN group with blood sample redrawn after only standard 8-10 h fasting and no bowel preparation (CNR); and 3/55 blood donors from the biobank considered as a healthy control group; (3) Results: The results showed that from the 514 patients undergoing colonoscopy, 247 had CN and 267 had CP. TLB parameters in these two groups were similar but different from those of the blood donors. The resampled patients (with normal colonoscopy and no bowel preparation) had similar TLB parameters to those of the blood donors. TLB parameters together with fluorescence spectra and other serum indicators (albumin and C-reactive protein) confirmed the statistically significant differences between normal colonoscopy patients with and without bowel preparation; (4) Conclusions: Bowel preparation seemed to alter serum protein levels and altered TLB parameters (different from a healthy subject). The diagnostic capability of other liquid-biopsy-based methods might also be compromised. Blood extraction after bowel preparation for colonoscopy should be avoided.

In vivo detection of circulating tumor cells predicts high-risk features in patients with bladder cancer

Previous studies have suggested the potential diagnostic value of circulating tumor cells (CTCs). This study aims to validate the efficacy of in vivo detection of CTCs in bladder cancer (BC) patients. A total of 216 BC patients were enrolled in this study. All patients had one in vivo detection of CTCs before initial treatment as a baseline parameter. The results of CTCs were associated with different clinicopathological features including molecular subtypes. PD-L1 expression on CTCs was also assessed and compared with its expression on tumors. CTC positive was defined as > 2 CTCs detected. Among all 216 patients, 49 (23%) were detected as CTC positive (> 2 CTCs) at baseline. Positive detection of CTCs was associated with multiple high-risk clinicopathological features including the multiplicity of the tumor (P = 0.02), tumor size (P < 0.01), tumor stage (P < 0.01), tumor grade (P < 0.01) and tumor PD-L1 expression (P = 0.01). The expression of PD-L1 on tumor and CTCs were not coordinated. Only 55% (74/134) matched the same status of PD-L1 expression on tumor and CTCs, along with 56 CTC ⁽⁺⁾ Tissue ^(-) and 4 CTC ^(-) Tissue ⁽⁺⁾ (P < 0.01). Our study has demonstrated the efficacy of in vivo detection of CTCs. The positive detection of CTCs is associated with multiple clinicopathological features. PD-L1 expression on CTCs has the potential to be a supplementary biomarker for immunotherapy.

In vivo detection demonstrates circulating tumor cell reduction instead of baseline number has prognostic value in bladder cancer patients receiving neoadjuvant chemotherapy

PURPOSE

Previous studies have suggested the potential prognostic value of circulating tumor cells (CTCs) in bladder cancer (BC) patients. This study aims to validate the prognostic value of in vivo detection of CTCs in muscle invasive bladder cancer (MIBC) patients receiving neoadjuvant chemotherapy (NAC).

METHODS

A total of 107 MIBC patients were enrolled in this study. All patients had one in vivo detection of CTCs before initial treatment as baseline, and those who received neoadjuvant chemotherapy (NAC) had a second detection after NAC and before radical cystectomy. CTCs dynamic change after NAC was analyzed. Prognostic value of in vivo CTCs detection was investigated.

RESULTS

Among 68 patients who received NAC, 45 patients (66%) had a CTC reduction after NAC. CTC reduction instead of baseline CTC positivity was a key prognostic factor for better progression free survival (PFS) among all MIBC patients receiving NAC in Kaplan-Meier analysis (P < 0.01) and in both crude (HR 6.14, 95%CI 1.63-23.21) and adjusted regression model (HR 6.76, 95% CI 1.59-28.88). The AUC was 0.85.

CONCLUSION

Our study demonstrated the prognostic value of in vivo detection of CTCs. The dynamic change of CTCs count may help evaluate the efficacy of NAC.

Dual-targeting surface-enhancement Raman scattering tags based on silver nanocubes for early diagnosis of pheochromocytoma

Pheochromocytoma (PCC), a rare tumor, often develops distant metastases after diagnosis, delaying early intervention treatment. In order to overcome the limitations of traditional diagnostic methods, dual-targeting Surface-Enhancement Raman Scattering (SERS) cytosensor was developed to identify and detect PCC-CTCs from peripheral blood. Meta-iodobenzylguanidine (MIBG) and octreotide-2,2',2″,2'''- (1,4,7,10 -tetraazacyclododecane-1,4,7,10-tetrayl) tetraacetic acid (DOTA) functionalized magnetic Fe₃O₄ and Ag-DTNB were prepared as capture probe and signal probe for SERS signal export, respectively. Ag nanocubes (AgNCs) as Raman active substrate offer an enhanced electromagnetic field, which could effectively enhance the signal intensity of DTNB and potentially realize trace analyte detection. The obtained SERS fingerprint spectroscopy possessed the characteristic of high sensitivity and resolution in the concentration range from 3.0-3.0 × 10⁶ cells mL^-1, with a detection limit of 1 cell mL^-1, which laterally compensated the deficiency of scarce CTCs in peripheral blood. This work provided new insight into PCC-CTCs accurate detection.

Deep learning assisted holography microscopy for in-flow enumeration of tumor cells in blood

Currently, detection of circulating tumor cells (CTCs) in cancer patient blood samples relies on immunostaining, which does not provide access to live CTCs, limiting the breadth of CTC-based applications. Here, we take the first steps to address this limitation, by demonstrating staining-free enumeration of tumor cells spiked into lysed blood samples using digital holographic microscopy (DHM), microfluidics and machine learning (ML). A 3D-printed module for laser assembly was developed to simplify the optical set up for holographic imaging of cells flowing through a sheath-based microfluidic device. Computational reconstruction of the holograms was performed to localize the cells in 3D and obtain the plane of best focus images to train deep learning models. We developed a custom-designed light-weight shallow Network dubbed s-Net and compared its performance against off-the-shelf CNN models including ResNet-50. The accuracy, sensitivity and specificity of the s-Net model was found to be higher than the off-the-shelf ML models. By applying an optimized decision threshold to mixed samples prepared in silico, the false positive rate was reduced from 1 × 10^-2 to 2.77 × 10^-4. Finally, the developed DHM-ML framework was successfully applied to enumerate spiked MCF-7 breast cancer cells and SkOV3 ovarian cancer cells from lysed blood samples containing white blood cells (WBCs) at concentrations typical of label-free enrichment techniques. We conclude by discussing the advances that need to be made to translate the DHM-ML approach to staining-free enumeration of actual CTCs in cancer patient blood samples.

Folate receptor-positive circulating tumor cell count, lymphocyte count and derived neutrophil-to- lymphocyte ratio for diagnosing lung cancer relapse

The folate receptor-positive circulating tumor cell (FR⁺-CTC) count can be used to improve the diagnosis rate of lung cancer. The lymphocyte count (LC) and derived neutrophil-to-lymphocyte ratio (dNLR) are involved in inflammatory processes. Whether the FR⁺-CTC count combined with the dNLR or LC is helpful for diagnosing lung cancer recurrence is not clear. Sixty-eight patients who were initially diagnosed with lung cancer and received first-line treatment were included. The clinicopathological characteristics, routine blood examination results and CTC examination results of the patients were collected. The role of the complete blood count and FR⁺-CTC count in lung cancer treatment response and prognosis was analyzed. The FR⁺-CTC count after treatment was significantly correlated with the T stage (p=0.005). Multivariate analysis showed that the pathological type and FR⁺-CTC count were independent predictors of disease-or progression-free survival (DFS/PFS) in patients with lung cancer (p=0.010 and p=0.030, respectively). The FR⁺-CTC count, LC and dNLR predicted the recurrence of lung cancer (sensitivity and specificity of the FR⁺-CTC count, 69.2% and 71.4%; the LC, 50.0% and 88.5%; and the dNLR, 50.0% and 88.1%, respectively). The FR⁺-CTC count combined with the LC or dNLR improved the diagnostic rate of lung cancer recurrence (sensitivity and specificity of the FR⁺-CTC count plus the LC, 53.8% and 90.5%, and the FR⁺-CTC count plus the dNLR, 73.1% and 73.8%, respectively). When these three indicators were combined to predict lung cancer recurrence, the AUC value was 0.817. The FR⁺-CTC count combined with the dNLR and/or LC after treatment can improve the diagnostic rate of lung cancer recurrence. A higher FR⁺-CTC count predicts worse DFS/PFS in patients with lung cancer.

SAIF: Label-Free Separation of Circulating Tumor Cells Using a Self-Amplified Inertial Focusing Microfluidic Chip

Circulating tumor cells (CTCs) are rare cells existing in the bloodstream with a relatively low number, which facilitate as a predictor of cancer progression. However, it is difficult to obtain highly purified intact CTCs with desired viability due to their low percentage among blood cells. In this chapter, we demonstrate the detailed steps for the fabrication and application of the novel self-amplified inertial-focused (SAIF) microfluidic chip that enables size-based, high-throughput, label-free separation of CTCs from the patient blood. The SAIF chip introduced in this chapter demonstrates the feasibility of an extremely narrow zigzag channel (with 40 μm channel width) connected with two expansion regions to effectively separate different-sized cells with amplified separation distance.

Does the Choice of Anaesthesia Affect Cancer? A Molecular Crosstalk between Theory and Practice

In recent years, there has been an increasing scientific interest in the interaction between anaesthesia and cancer development. Retrospective studies show that the choice of anaesthetics may influence cancer outcome and cancer recurrence; however, these studies show contradictory results. Recently, some large randomized clinical trials have been completed, yet they show no significant effect of anaesthetics on cancer outcomes. In this scoping review, we compiled a body of in vivo and in vitro studies with the goal of evaluating the biological effects of anaesthetics on cancer cells in comparison to clinical effects as described in recent studies. It was found that sevoflurane, propofol, opioids and lidocaine are likely to display direct biological effects on cancer cells; however, significant effects are only found in studies with exposure to high concentrations of anaesthetics and/or during longer exposure times. When compared to clinical data, these differences in exposure and dose-effect relation, as well as tissue selectivity, population selection and unclear anaesthetic dosing protocols might explain the lack of outcome.

A Multi-Center Clinical Study to Harvest and Characterize Circulating Tumor Cells from Patients with Metastatic Breast Cancer Using the Parsortix® PC1 System

Circulating tumor cells (CTCs) captured from the blood of cancer patients may serve as a surrogate source of tumor material that can be obtained via a venipuncture (also known as a liquid biopsy) and used to better understand tumor characteristics. However, the only FDA-cleared CTC assay has been limited to the enumeration of surface marker-defined cells and not further characterization of the CTCs. In this study, we tested the ability of a semi-automated device capable of capturing and harvesting CTCs from peripheral blood based on cell size and deformability, agnostic of cell-surface markers (the Parsortix® PC1 System), to yield CTCs for evaluation by downstream techniques commonly available in clinical laboratories. The data generated from this study were used to support a De Novo request (DEN200062) for the classification of this device, which the FDA recently granted. As part of a multicenter clinical trial, peripheral blood samples from 216 patients with metastatic breast cancer (MBC) and 205 healthy volunteers were subjected to CTC enrichment. A board-certified pathologist enumerated the CTCs from each participant by cytologic evaluation of Wright-Giemsa-stained slides. As proof of principle, cells harvested from a concurrent parallel sample provided by each participant were evaluated using one of three additional evaluation techniques: molecular profiling by qRT-PCR, RNA sequencing, or cytogenetic analysis of HER2 amplification by FISH. The study demonstrated that the Parsortix® PC1 System can effectively capture and harvest CTCs from the peripheral blood of MBC patients and that the harvested cells can be evaluated using orthogonal methodologies such as gene expression and/or Fluorescence In Situ Hybridization (FISH).

Aptamer-Based Cancer Cell Analysis and Treatment

Aptamers are a class of single-stranded DNA or RNA oligonucleotides that can exclusively bind to various targets with high affinity and selectivity. Regarded as "chemical antibodies", aptamers possess several intrinsic advantages, including easy synthesis, convenient modification, high programmability, and good biocompatibility. In recent decades, many studies have demonstrated the superiority of aptamers as molecular tools for various biological applications, particularly in the area of cancer theranostics. In this review, we focus on recent progress in developing aptamer-based strategies for the precise analysis and treatment of cancer cells.

Optimizing Immunofunctionalization and Cell Capture on Micromolded Hydrogels via Controlled Oxygen-Inhibited Photopolymerization

With circulating tumor cells (CTCs) playing a critical role in cancer metastasis, the quantitation and characterization of CTCs promise to provide precise diagnostic and prognostic information in service of personalized therapies. However, as CTCs are extremely rare, high yield, high purity strategies are required to target and isolate CTCs from patient samples. Recently, we demonstrated the selective capture of CTCs upon antibody-functionalized polyethylene glycol diacrylate (PEGDA) hydrogels photopolymerized within polydimethylsiloxane (PDMS) microfluidic molds. Isolated CTC purity was subsequently enriched by selectively releasing desired cells from photodegradable hydrogel capture surfaces. However, the fabrication of these acrylate-based hydrogels by photopolymerization is subject to oxygen inhibition, which dramatically affects the physical and chemical properties of hydrogel interfaces formed in proximity to PDMS boundaries. To evaluate how antibody conjugation density and cell capture is impacted by fabrication parameters affected by oxygen inhibition, PEGDA hydrogel features were polymerized within PDMS micromolds under different UV exposure conditions and linker (acrylate-PEG-biotin) concentrations. Predictions of acrylate conversion throughout the hydrogel feature were performed using a 1D reaction-diffusion model that describes oxygen-inhibited photopolymerization. The functional consequences of photopolymerization parameters and solution stoichiometry on CTC capture were experimentally quantified and evaluated. Results show that hydrogel surfaces polymerized under shorter exposure times and with higher linker concentrations display superior functionalization and higher CTC capture efficiency. Conversely, highly cross-linked hydrogel surfaces polymerized under longer exposure times are insensitive to functionalization and display poor capture, regardless of linker concentration. By highlighting the importance of oxygen-inhibited photopolymerization, these findings provide guidelines to design micromolded hydrogels with controlled ligand expression. In addition to enhancing the selective cell capture capacity of immunofunctional hydrogels, the ability to quantifiably design hydrogel interfaces described here will improve the sensitivity of hydrogel biosensors, provide a platform to finely screen cell-matrix interactions, and generally enhance the fidelity of micromolded hydrogel features.

Liquid Biopsy Analysis as a Tool for TKI-Based Treatment in Non-Small Cell Lung Cancer

The treatment of non-small cell lung cancer (NSCLC) has recently evolved with the introduction of targeted therapy based on the use of tyrosine kinase inhibitors (TKIs) in patients with certain gene alterations, including EGFR, ALK, ROS1, BRAF, and MET genes. Molecular targeted therapy based on TKIs has improved clinical outcomes in a large number of NSCLC patients with advanced disease, enabling significantly longer progression-free survival (PFS). Liquid biopsy is an increasingly popular diagnostic tool for treating TKI-based NSCLC. The studies presented in this article show that detection and analysis based on liquid biopsy elements such as circulating tumor cells (CTCs), cell-free DNA (cfDNA), exosomes, and/or tumor-educated platelets (TEPs) can contribute to the appropriate selection and monitoring of targeted therapy in NSCLC patients as complementary to invasive tissue biopsy. The detection of these elements, combined with their molecular analysis (using, e.g., digital PCR (dPCR), next generation sequencing (NGS), shallow whole genome sequencing (sWGS)), enables the detection of mutations, which are required for the TKI treatment. Despite such promising results obtained by many research teams, it is still necessary to carry out prospective studies on a larger group of patients in order to validate these methods before their application in clinical practice.

Shining a Light on Cancer - Photonics in Microfluidic Tumor Modelling and Biosensing

Microfluidic platforms represent a powerful approach to miniaturizing important characteristics of cancers, improving in vitro testing by increasing physiological relevance. Different tools can manipulate cells and materials at the microscale, but few offer the efficiency and versatility of light and optical technologies. Moreover, light-driven technologies englobe a broad toolbox for quantifying critical biological phenomena. Herein, we review the role of photonics in microfluidic 3D cancer modeling and biosensing from three major perspectives. First, we look at optical-driven technologies that allow biomaterials and living cells to be manipulated with micro-sized precision and the opportunities to advance 3D microfluidic models by engineering cancer microenvironments' hallmarks, such as their architecture, cellular complexity, and vascularization. Second, we delve into the growing field of optofluidics, exploring how optical tools can directly interface microfluidic chips, enabling the extraction of relevant biological data, from single fluorescent signals to the complete 3D imaging of diseased cells within microchannels. Third, we review advances in optical cancer biosensing, focusing on how light-matter interactions can detect biomarkers, rare circulating tumor cells, and cell-derived structures such as exosomes. We overview photonic technologies' current challenges and caveats in microfluidic 3D cancer models, outlining future research avenues that may catapult the field. This article is protected by copyright. All rights reserved.

A micropillar array-based microfluidic chip for label-free separation of circulating tumor cells: The best micropillar geometry?

INTRODUCTION

The information derived from the number and characteristics of circulating tumor cells (CTCs), is crucial to ensure appropriate cancer treatment monitoring. Currently, diverse microfluidic platforms have been developed for isolating CTCs from blood, but it remains a challenge to develop a low-cost, practical, and efficient strategy.

OBJECTIVES

This study aimed to isolate CTCs from the blood of cancer patients via introducing a new and efficient micropillar array-based microfluidic chip (MPA-Chip), as well as providing prognostic information and monitoring the treatment efficacy in cancer patients.

METHODS

We fabricated a microfluidic chip (MPA-Chip) containing arrays of micropillars with different geometries (lozenge, rectangle, circle, and triangle). We conducted numerical simulations to compare velocity and pressure profiles inside the micropillar arrays. Also, we experimentally evaluated the capture efficiency and purity of the geometries using breast and prostate cancer cell lines as well as a blood sample. Moreover, the device's performance was validated on 12 patients with breast cancer (BC) in different states.

RESULTS

The lozenge geometry was selected as the most effective and optimized micropillar design for CTCs isolation, providing high capture efficiency (>85 %), purity (>90 %), and viability (97 %). Furthermore, the lozenge MPA-chip was successfully validated by the detection of CTCs from 12 breast cancer (BC) patients, with non-metastatic (median number of 6 CTCs) and metastatic (median number of 25 CTCs) diseases, showing different prognoses. Also, increasing the chemotherapy period resulted in a decrease in the number of captured CTCs from 23 to 7 for the metastatic patient. The MPA-Chip size was only 0.25 cm² and the throughput of a single chip was 0.5 ml/h, which can be increased by multiple MPA-Chips in parallel.

CONCLUSION

The lozenge MPA-Chip presented a novel micropillar geometry for on-chip CTC isolation, detection, and staining, and in the future, the possibilities can be extended to the culture of the CTCs.

Label-free enrichment of MCF7 breast cancer cells from leukocytes using continuous flow dielectrophoresis

Circulating tumor cells (CTCs) present in the bloodstream are strongly linked to the invasive behavior of cancer; therefore, their detection holds great significance for monitoring disease progression. Currently available CTC isolation tools are often based on tumor-specific antigen or cell size approaches. However, these techniques are limited due to the lack of a unique and universal marker for CTCs, and the overlapping size between CTCs and regular blood cells. Dielectrophoresis (DEP), governed by the intrinsic dielectric properties of the particles, is a promising marker-free, accurate, fast, and low-cost technique that enables the isolation of CTCs from blood cells. This study presents a continuous flow, antibody-free DEP-based microfluidic device to concentrate MCF7 breast cancer cells, a well-established CTC model, in the presence of leukocytes extracted from human blood samples. The enrichment strategy was determined according to the DEP responses of the corresponding cells, obtained in our previously reported DEP spectrum study. It was based on the positive-DEP integrated with hydrodynamic focusing under continuous flow. In the proposed device, the parylene microchannel with two inlets and outlets was built on top of rectangular and equally spaced isolated planar electrodes rotated certain degree relative to the main flow (13°). The recovery of MCF7 cells mixed with leukocytes was 74%-98% at a frequency of 1 MHz and a magnitude of 10-12 V_pp . Overall, the results revealed that the presented system successfully concentrates MCF7 cancer cells from leukocytes, ultimately verifying our DEP spectrum study, in which the enrichment frequency and separation strategy of the microfluidic system were determined.

Studies on the Effect of Graphene Oxide Deposited on Gold and Nickel Microsieves on Prostate Cancer Cells DU 145

This work shows the effect of graphene oxide deposition on microsieves’ surfaces of gold and nickel foils, on DU 145 tumor cells of the prostate gland. The sieves were made by a laser ablation process. The graphene oxide (GO) deposition process was characterized by the complete covering of the inner edges of the microholes and the flat surface between the holes with GO. Electron microscanning studies have shown that due to the deposition method applied, graphene oxide flakes line the interior of the microholes, reducing the unevenness of the downstream surfaces during the laser ablation process. The presence of graphene oxide was confirmed by Fourier infrared spectroscopy. During the screening (sieving) process, the microsieves were placed in a sieve column. Gold foil is proven to be a very good material for the screening of cancer cells, but even more so after screening as a substrate for re-culture of the DU 145. This allows a potential recovery of the cells and the development of a targeted therapy. The sieved cells were successfully grown on the microsieves used in the experiment. Graphene oxide remaining on the surface of the nickel sieve has been observed to increase the sieving effect. Although graphene oxide improved separation efficiency by 9.7%, the nickel substrate is not suitable for re-culturing of the Du 145 cells and the development of a targeted therapy compared to the gold one.

Target receptor identification and subsequent treatment of resected brain tumors with encapsulated and engineered allogeneic stem cells

Cellular therapies offer a promising therapeutic strategy for the highly malignant brain tumor, glioblastoma (GBM). However, their clinical translation is limited by the lack of effective target identification and stringent testing in pre-clinical models that replicate standard treatment in GBM patients. In this study, we show the detection of cell surface death receptor (DR) target on CD146-enriched circulating tumor cells (CTC) captured from the blood of mice bearing GBM and patients diagnosed with GBM. Next, we developed allogeneic "off-the-shelf" clinical-grade bifunctional mesenchymal stem cells (MSCBif) expressing DR-targeted ligand and a safety kill switch. We show that biodegradable hydrogel encapsulated MSCBif (EnMSCBif) has a profound therapeutic efficacy in mice bearing patient-derived invasive, primary and recurrent GBM tumors following surgical resection. Activation of the kill switch enhances the efficacy of MSCBif and results in their elimination post-tumor treatment which can be tracked by positron emission tomography (PET) imaging. This study establishes a foundation towards a clinical trial of EnMSCBif in primary and recurrent GBM patients.

A Novel Karyoplasmic Ratio-Based Automatic Recognition Method for Identifying Glioma Circulating Tumor Cells

Background

Detection of circulating tumor cells (CTCs) is a promising technology in tumor management; however, the slow development of CTC identification methods hinders their clinical utility. Moreover, CTC detection is currently challenging owing to major issues such as isolation and correct identification. To improve the identification efficiency of glioma CTCs, we developed a karyoplasmic ratio (KR)-based identification method and constructed an automatic recognition algorithm. We also intended to determine the correlation between high-KR CTC and patients’ clinical characteristics.

Methods

CTCs were isolated from the peripheral blood samples of 68 glioma patients and analyzed using DNA-seq and immunofluorescence staining. Subsequently, the clinical information of both glioma patients and matched individuals was collected for analyses. ROC curve was performed to evaluate the efficiency of the KR-based identification method. Finally, CTC images were captured and used for developing a CTC recognition algorithm.

Results

KR was a better parameter than cell size for identifying glioma CTCs. We demonstrated that low CTC counts were independently associated with isocitrate dehydrogenase (IDH) mutations (p = 0.024) and 1p19q co-deletion status (p = 0.05), highlighting its utility in predicting oligodendroglioma (area under the curve = 0.770). The accuracy, sensitivity, and specificity of our algorithm were 93.4%, 81.0%, and 97.4%, respectively, whereas the precision and F1 score were 90.9% and 85.7%, respectively.

Conclusion

Our findings remarkably increased the efficiency of detecting glioma CTCs and revealed a correlation between CTC counts and patients’ clinical characteristics. This will allow researchers to further investigate the clinical utility of CTCs. Moreover, our automatic recognition algorithm can maintain high precision in the CTC identification process, shorten the time and cost, and significantly reduce the burden on clinicians.

Self-propelled micro/nanobots: A new insight into precisely targeting cancerous cells through intelligent and deep cancer penetration

Cancer overlooks are globally one of the most dangerous and life-threatening tribulations. While significant advances have been made in the targeted delivery of anti-cancer medications over the last few years, several challenges, such as low efficacy and strong toxic effects, remain to be addressed. Micro/nanomotors have been thoroughly studied for both effective cancer detection and treatment, as demonstrated by significant advancements in the architecture of smart and functional micro/nanomotor biomedical systems. Able to self-propelled within fluid media, micro/nanomotors have attractive vehicles to maximize the efficacy of tumor delivery. Here, we present the current developments in the delivery, detection, and imaging-guided treatment of micro/nanomotors in the clinical field, including cancer-related specific targeted drug delivery, and then discuss the barriers and difficulties encountered by micro/nanomotors throughout the medical process. Furthermore, this paper addresses the potential growth of micro/nanomotors for medical applications, and sets out the current drawbacks and future research directions for more advancement.

Comprehensive Atlas of Circulating Rare Cells Detected by SE-iFISH and Image Scanning Platform in Patients With Various Diseases

Objective

Circulating rare cells (CRCs) are known as a crucial nucleated cellular response to pathological conditions, yet the landscape of cell types across a wide variety of diseases lacks comprehensive understanding. This study aimed at detecting and presenting a full spectrum of highly heterogeneous CRCs in clinical practice and further explored the characterization of CRC subtypes in distinct biomarker combinations and aneuploid chromosomes among various disease groups.

Methods

Peripheral blood was obtained from 2,360 patients with different cancers and non-neoplastic diseases. CRC capture and identification were accomplished using a novel platform integrating subtraction enrichment and immunostaining-fluorescence in situ hybridization (SE-iFISH) strategy with a high-throughput automated image scanning system, on which hemocyte, tumor, epithelial, endothelial, mesenchymal, and stemness biomarkers were immunostained and displayed simultaneously. Double chromosome enumeration probe (CEP8 and CEP12) co-detection was performed on isolated CRCs from an extended trial for two chromosome ploidy patterns.

Results

A comprehensive atlas categorizing the diverse CRCs into 71 subtypes outlining was mapped out. The presence of epithelial-mesenchymal transition (EMT) or endothelial-mesenchymal transition (EndoMT), the cells with progenitor property, hematologic CRCs expressing multiple biomarkers, CRCs at "naked nuclei" status, and the rarely reported aneuploid mesenchymal epithelial-endothelial fusion cluster were described. Circulating tumor cells (CTCs) were detected in 2,157 (91.4%) patients; the total numbers of CTCs and circulating tumor-derived endothelial cells (CTECs) were relatively higher in several digestive system cancer types and non-neoplastic infectious diseases (p < 0.05). Co-detection combining CEP8 and CEP12 showed a higher diagnostic specificity on account of 57.27% false negativity of CRC detection through a single probe of CEP8.

Conclusions

The alternative biomarkers and chromosomes to be targeted by SE-iFISH and the image scanning platform, along with the comprehensive atlas, offer insight into the heterogeneity of CRCs and reveal potential contributions to specific disease diagnosis and therapeutic target cell discovery.

Precisely Detecting the Telomerase Activities by an AIEgen Probe with Dual Signal Outputs after Cell-Cycle Synchronization

By maintaining the telomere lengths, telomerase can make the tumor cells avoid the apoptosis, thus, achieving the cell immortalization. In the past, a series of telomerase detection systems have been developed through utilizing the unique characteristic of telomerase extended primer. However, fluctuation of telomerase activity, along with the cell cycle progression, leads to ambiguous detection results. Here, we reported a dual signal output detection strategy based on cell-cycle synchronization for precisely detecting telomerase activities by using a new AIEgen probe SSNB. Experimental and simulating calculation results demonstrated that positively charged SSNB could interact with DNA through the electrostatic interaction and π-π interaction, as well as the hydrogen bonds. The aggregation of SSNB caused by the extended template strand primer (TP) could be observed in tumor cells, thus, indicating the telomerase activity in various cell lines. Furthermore, after cell cycle synchronization, it was found that the telomerase activity in the S phase was the highest, no matter from the fluorescence intensity or the ROS generation situation. Dual signal outputs of SSNB verified the significance and necessity of cell-cycle synchronization detection for telomerase activity. This strategy could open a new window for the biotargets of which activity is variational in time dimension.

Liquid Biopsy: A Distinctive Approach to the Diagnosis and Prognosis of Cancer

Cancer is a leading cause of morbidity and mortality worldwide. Over the past decades, the concept of precision cancer medicine has emerged as a novel approach in the field of oncology that aims to tailor the most effective treatment options to each individual cancer patient based on the genetic profile of the tumor of each individual patient. Recently, tissue biopsy has become an essential part of cancer care and is widely used to characterize the tumor. However, tissue biopsy techniques face different challenges due to their invasiveness, cost, time, and adversity in potential sampling due to tissue heterogeneity. To overcome these issues, a non-invasive approach has developed, which is known as liquid biopsy. It is a simple, fast, and worthwhile technique based on the analysis of circulating tumor DNA (which is a fraction of cfDNA), circulating tumor cells (CTCs), and other tumor-derived material in blood plasma. This review provides an overview of the concept of liquid biopsy and briefly discusses the role of ctDNA and CTC analysis as tools for early diagnosis and prognosis of cancer. In this review, we also speculate on the advantages of liquid biopsy as opposed to tissue biopsy and postulate that liquid biopsy may be a comprehensive approach to overcome the current limitations associated with costly, invasive, and time-consuming tissue biopsy.

A Narrow Straight Microchannel Array for Analysis of Transiting Speed of Floating Cancer Cells

Investigating floating cells along a narrow microchannel (e.g., a blood vessel) for their transiting speeds and the corresponding roles of cell physical properties can deepen our understanding of circulating tumor cells (CTCs) metastasis via blood vessels. Many existing studies focus on the cell transiting process in blood vessel-like microchannels; further analytical studies are desired to summarize behaviors of the floating cell movement under different conditions. In this work, we perform a theoretical analysis to establish a relation between the transiting speed and key cell physical properties. We also conduct computational fluid dynamics simulation and microfluidic experiments to verify the theoretical model. This work reveals key cell physical properties and the channel configurations determining the transiting speed. The reported model can be applied to other works with various dimensions of microchannels as a more general way to evaluate the cancer cell metastasis ability with microfluidics.

Basic Principles and Recent Advances in Magnetic Cell Separation

Magnetic cell separation has become a key methodology for the isolation of target cell populations from biological suspensions, covering a wide spectrum of applications from diagnosis and therapy in biomedicine to environmental applications or fundamental research in biology. There now exists a great variety of commercially available separation instruments and reagents, which has permitted rapid dissemination of the technology. However, there is still an increasing demand for new tools and protocols which provide improved selectivity, yield and sensitivity of the separation process while reducing cost and providing a faster response. This review aims to introduce basic principles of magnetic cell separation for the neophyte, while giving an overview of recent research in the field, from the development of new cell labeling strategies to the design of integrated microfluidic cell sorters and of point-of-care platforms combining cell selection, capture, and downstream detection. Finally, we focus on clinical, industrial and environmental applications where magnetic cell separation strategies are amongst the most promising techniques to address the challenges of isolating rare cells.

A Model-Based Approach To Detection Of The Circulating Melanoma Cells From The Photoacoustic Cytometry Data

Background ― Effective treatment of melanoma is only possible during the early stages of the disease. However, current techniques of cancer diagnostics are not sensitive enough to be reliable during the early stages. Photoacoustic cytometry provides a very perspective method for early diagnostics, which, in principle, can detect even a single melanoma circulating melanoma cell. However, the photoacoustic monitoring system needs to be paired with an effective automated algorithm, which will detect acoustic responses from melanoma cells among normal blood cells. Objective ― The study aims to compare the currently adopted algorithm for the detection of circulating melanoma cells based on a calculation of the standard deviation of the acoustic responses with the new model-based algorithm. Methods ― We tested and compared two different methods of automated detection of melanoma acoustic responses. The first approach was based on a calculation of the deviation of the acoustic responses. The second approach was based on the subtraction of the ensemble average normal acoustic response from melanoma acoustic responses. The resulting differential signals contained positive spikes, which were detected. Results ― The model-based approach demonstrated better sensitivity and specificity when detecting circulating melanoma cells in comparison to the approach based on the calculation of standard deviation of the acoustic responses. Conclusions ― Obtained results suggest that the model-based approach is a more reliable basis for an automated algorithm for the detection of circulating melanoma cells. The model-based approach has an additional advantage of being simpler to calculate and requires less computational power to run in real-time.

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.

Research progress on circulating tumor cells of hepatocellular carcinoma

Circulating tumor cells (CTCs) are the cells released from the primary tumor and found in the peripheral blood, which can colonize and develop at a distance through blood circulation. At present, the commonly used separation and detection methods of CTCs are mainly divided into physical methods, biological methods, and microfluidic chip-based methods. Monitoring CTC count and cell phenotype is of great significance for early screening and diagnosis of hepatocellular carcinoma (HCC). Moreover, the CTC count and cell phenotype are related to assessing the clinical efficacy of the treatment of HCC and the clinical stage of HCC patients. The CTCs count is also closely related to the overall survival, progression-free survival, and postoperative recurrence of patients with HCC.

Immunomagnetic separation in a novel cavity-added serpentine microchannel structure for the selective isolation of lung adenocarcinoma cells

The manipulation and separation of circulating tumor cells (CTCs) in continuous fluidic flows play an essential role in various biomedical applications, particularly the early diagnosis and treatment of diseases. Recent advances in magnetic bead development have provided promising solutions to the challenges encountered in CTC manipulation and isolation. In this study, we proposed a biomicrofluidic platform for specifically isolating human lung carcinoma A549 cells in microfluidic channels. The principle of separation was based on the effect of the magnetic field on aptamer-conjugated magnetic beads, also known as immunomagnetic beads, in a serpentine microchannel with added cavities (SMAC). The magnetic cell separation performance of the proposed structure was modeled and simulated by using COMSOL Multiphysics. The experimental procedures for aptamer molecular conjugation on 1.36 µm-diameter magnetic beads and magnetic bead immobilization on A549 cells were also reported. The lung carcinoma cell-bead complexes were then experimentally separated by an external magnetic field. Separation performance was also confirmed by optical microscopic observations and fluorescence analysis, which showed the high selectivity and efficiency of the proposed system in the isolation and capture of A549 cells in our proposed SMAC. At the flow rate of 5 µL/s, the capture rate of human lung carcinoma cells exceeded 70% in less than 15 min, whereas that of the nontarget cells was approximately 4%. The proposed platform demonstrated its potential for high selectivity, portability, and facile operation, which are suitable considerations for developing point-of-care applications for various biological and clinical purposes.

Recent advances in dielectrophoresis toward biomarker detection: A summary of studies published between 2014 and 2021

Dielectrophoresis is a well-understood phenomenon that has been widely utilized in biomedical applications. Recent advancements in miniaturization have contributed to the development of dielectrophoretic-based devices for a wide variety of biomedical applications. In particular, the integration of dielectrophoresis with microfluidics, fluorescence, and electrical impedance has produced devices and techniques that are attractive for screening and diagnosing diseases. This review article summarizes the recent utility of dielectrophoresis in assays of biomarker detection. Common screening and diagnostic biomarkers, such as cellular, protein, and nucleic acid, are discussed. Finally, the potential use of recent developments in machine learning approaches toward improving biomarker detection performance is discussed. This review article will be useful for researchers interested in the recent utility of dielectrophoresis in the detection of biomarkers and for those developing new devices to address current gaps in dielectrophoretic biomarker detection.

Recent Development of Nanomaterials-Based Cytosensors for the Detection of Circulating Tumor Cells

The accurate analysis of circulating tumor cells (CTCs) holds great promise in early diagnosis and prognosis of cancers. However, the extremely low abundance of CTCs in peripheral blood samples limits the practical utility of the traditional methods for CTCs detection. Thus, novel and powerful strategies have been proposed for sensitive detection of CTCs. In particular, nanomaterials with exceptional physical and chemical properties have been used to fabricate cytosensors for amplifying the signal and enhancing the sensitivity. In this review, we summarize the recent development of nanomaterials-based optical and electrochemical analytical techniques for CTCs detection, including fluorescence, colorimetry, surface-enhanced Raman scattering, chemiluminescence, electrochemistry, electrochemiluminescence, photoelectrochemistry and so on.

Nanotherapeutics and nanotheragnostics for cancers: properties, pharmacokinetics, biopharmaceutics, and biosafety

With the worldwide increasing rate of chronic diseases, such as cancer, the development of novel techniques to improve the efficacy of therapeutic agents is highly demanded. Nanoparticles are especially well suited to encapsulate drugs and other therapeutic agents, bringing additional advantages, such as less frequent dosage requirements, reduced side effects due to specific targeting, and therefore increased patient compliance. However, with the increasing use of nanoparticles and their recent launch on the pharmaceutical market it is important to achieve high quality control of these advanced systems. In this review, we discuss the properties of different nanoparticles, the pharmacokinetics, the biosafety issues of concern, and conclude with novel nanotherapeutics and nanotheragnostics for cancer drug delivery.