Circulating tumour cells predict recurrences and survival in head and neck squamous cell carcinoma patients.

Patients with head and neck squamous cell carcinoma (HNSCC) are at a high risk of developing recurrence and secondary cancers. This study evaluates the prognostic and surveillance utilities of circulating tumour cells (CTCs) in HNSCC. A total of 154 HNSCC patients were recruited and followed up for 4.5 years. Blood samples were collected at baseline and follow-up. CTCs were isolated using a spiral microfluid device. Recurrence and death due to cancer were assessed during the follow-up period. In patients with HNSCC, the presence of CTCs at baseline was a predictor of recurrence (OR = 8.40, p < 0.0001) and death (OR= ∞, p < 0.0001). Patients with CTCs at baseline had poor survival outcomes (p < 0.0001). Additionally, our study found that patients with CTCs in a follow-up appointment were 2.5 times more likely to experience recurrence or death from HNSCC (p < 0.05) prior to their next clinical visit. Our study highlights the prognostic and monitoring utilities of CTCs' in HNSCC patients. Early identification of CTCs facilitates precise risk assessment, guiding treatment choices and ultimately enhancing patient outcomes.

Enrichment of T-lymphocytes from leukemic blood using inertial microfluidics toward improved chimeric antigen receptor-T cell manufacturing.

Chimeric antigen receptor cell therapy is a successful immunotherapy for the treatment of blood cancers. However, hurdles in their manufacturing remain including efficient isolation and purification of the T-cell starting material. Herein, we describe a one-step separation based on inertial spiral microfluidics for efficient enrichment of T-cells in B-cell acute lymphoblastic leukemia (ALL) and B-cell chronic lymphocytic leukemia patient's samples. In healthy donors used to optimize the process, the lymphocyte purity was enriched from 65% (SD ± 0.2) to 91% (SD ± 0.06) and T-cell purity was enriched from 45% (SD ± 0.1) to 73% (SD ± 0.02). Leukemic samples had higher starting B-cells compared to the healthy donor samples. Efficient enrichment and recovery of lymphocytes and T-cells were achieved in ALL samples with B-cells, monocytes and leukemic blasts depleted by 80% (SD ± 0.09), 89% (SD ± 0.1) and 74% (SD ± 0.09), respectively, and a 70% (SD ± 0.1) T-cell recovery. Chronic lymphocytic leukemia samples had lower T-cell numbers, and the separation process was less efficient compared to the ALL. This study demonstrates the use of inertial microfluidics for T-cell enrichment and depletion of B-cell blasts in ALL, suggesting its potential to address a key bottleneck of the chimeric antigen receptor-T manufacturing workflow.

Evaluation of an artificial intelligence-facilitated sperm detection tool in azoospermic samples for use in ICSI.

RESEARCH QUESTION: Can artificial intelligence (AI) improve the efficiency and efficacy of sperm searches in azoospermic samples? DESIGN: This two-phase proof-of-concept study began with a training phase using eight azoospermic patients (>10,000 sperm images) to provide a variety of surgically collected samples for sperm morphology and debris variation to train a convolutional neural network to identify spermatozoa. Second, side-by-side testing was undertaken on two cohorts of non-obstructive azoospermia patient samples: an embryologist versus the AI identifying all the spermatozoa in the still images (cohort 1, n = 4), and a side-by-side test with a simulated clinical deployment of the AI model with an intracytoplasmic sperm injection microscope and the embryologist performing a search with and without the aid of the AI (cohort 2, n = 4). RESULTS: In cohort 1, the AI model showed an improvement in the time taken to identify all the spermatozoa per field of view (0.02 ± 0.30  ×  10-5s versus 36.10 ± 1.18s, P < 0.0001) and improved recall (91.95 ± 0.81% versus 86.52 ± 1.34%, P < 0.001) compared with an embryologist. From a total of 2660 spermatozoa to find in all the samples combined, 1937 were found by an embryologist and 1997 were found by the AI in less than 1000th of the time. In cohort 2, the AI-aided embryologist took significantly less time per droplet (98.90 ± 3.19 s versus 168.7 ± 7.84 s, P < 0.0001) and found 1396 spermatozoa, while 1274 were found without AI, although no significant difference was observed. CONCLUSIONS: AI-powered image analysis has the potential for seamless integration into laboratory workflows, to reduce the time to identify and isolate spermatozoa from surgical sperm samples from hours to minutes, thus increasing success rates from these treatments.

A placenta-on-a-chip model to determine the regulation of FKBPL and galectin-3 in preeclampsia.

Preeclampsia is a pregnancy-specific cardiovascular disorder, involving significant maternal endothelial dysfunction. Although inappropriate placentation due to aberrant angiogenesis, inflammation and shallow trophoblast invasion are the root causes of preeclampsia, pathogenic mechanisms are poorly understood, particularly in early pregnancy. Here, we first confirm the abnormal expression of important vascular and inflammatory proteins, FK506-binding protein-like (FKBPL) and galectin-3 (Gal-3), in human plasma and placental tissues from women with preeclampsia and normotensive controls. We then employ a three-dimensional microfluidic placental model incorporating human umbilical vein endothelial cells (HUVECs) and a first trimester trophoblast cell line (ACH-3P) to investigate FKBPL and Gal-3 signaling in inflammatory conditions. In human samples, both circulating (n = 17 controls; n = 30 preeclampsia) and placental (n ≥ 6) FKBPL and Gal-3 levels were increased in preeclampsia compared to controls (plasma: FKBPL, p < 0.0001; Gal-3, p < 0.01; placenta: FKBPL, p < 0.05; Gal-3, p < 0.01), indicative of vascular dysfunction in preeclampsia. In our placenta-on-a-chip model, we show that endothelial cells are critical for trophoblast-mediated migration and that trophoblasts effectively remodel endothelial vascular networks. Inflammatory cytokine tumour necrosis factor-α (10 ng/mL) modulates both FKBPL and Gal-3 signaling in conjunction with trophoblast migration and impairs vascular network formation (p < 0.005). Our placenta-on-a-chip recapitulates aspects of inappropriate placental development and vascular dysfunction in preeclampsia.

Advanced models for respiratory disease and drug studies.

The global burden of respiratory diseases is enormous, with many millions of people suffering and dying prematurely every year. The global COVID-19 pandemic witnessed recently, along with increased air pollution and wildfire events, increases the urgency of identifying the most effective therapeutic measures to combat these diseases even further. Despite increasing expenditure and extensive collaborative efforts to identify and develop the most effective and safe treatments, the failure rates of drugs evaluated in human clinical trials are high. To reverse these trends and minimize the cost of drug development, ineffective drug candidates must be eliminated as early as possible by employing new, efficient, and accurate preclinical screening approaches. Animal models have been the mainstay of pulmonary research as they recapitulate the complex physiological processes, Multiorgan interplay, disease phenotypes of disease, and the pharmacokinetic behavior of drugs. Recently, the use of advanced culture technologies such as organoids and lung-on-a-chip models has gained increasing attention because of their potential to reproduce human diseased states and physiology, with clinically relevant responses to drugs and toxins. This review provides an overview of different animal models for studying respiratory diseases and evaluating drugs. We also highlight recent progress in cell culture technologies to advance integrated models and discuss current challenges and present future perspectives.

Immunotherapeutic targets in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is one of the most common types of cancer in the world and has a 5-year survival rate of ~20%. Immunotherapies have shown promising results leading to durable responses, however, they are only effective for a subset of patients. To determine the best therapeutic approach, a thorough and in-depth profiling of the tumour microenvironment (TME) is required. The TME is a complex network of cell types that form an interconnected network, promoting tumour cell initiation, growth and dissemination. The stroma, immune cells and endothelial cells that comprise the TME generate a plethora of cytotoxic or cytoprotective signalling pathways. In this review, we discuss immunotherapeutic targets in NSCLC tumours and how the TME may influence patients' response to immunotherapy.

Thiolate DNAzymes on Gold Nanoparticles for Isothermal Amplification and Detection of Mesothelioma-derived Exosomal PD-L1 mRNA.

Catalytic DNAzymes have been used for isothermal amplification and rapid detection of nucleic acids, holding the potential for point-of-care testing applications. However, when Subzymes (universal substrate and DNAzyme) are tethered to the polystyrene magnetic microparticles via biotin-streptavidin bonds, the residual free Subzymes are often detached from the microparticle surface, which causes a significant degree of false positives. Here, we attached dithiol-modified Subzyme to gold nanoparticle and improved the limit of detection (LoD) by 200 times compared to that using magnetic microparticles. As a proof of concept, we applied our new method for the detection of exosomal programed cell-death ligand 1 (PD-L1) RNA. As the classical immune checkpoint, molecule PD-L1, found in small extracellular vesicles (sEVs, traditionally called exosomes), can reflect the antitumor immune response for predicting immunotherapy response. We achieved the LoD as low as 50 fM in detecting both the RNA homologous to the PD-L1 gene and exosomal PD-L1 RNAs extracted from epithelioid and nonepithelioid subtypes of mesothelioma cell lines, which only takes 8 min of reaction time. As the first application of isothermal DNAzymes for detecting exosomal PD-L1 RNA, this work suggests new point-of-care testing potentials toward clinical translations.

Machine learning reveals mesenchymal breast carcinoma cell adaptation in response to matrix stiffness.

Epithelial-mesenchymal transition (EMT) and its reverse process, mesenchymal-epithelial transition (MET), are believed to play key roles in facilitating the metastatic cascade. Metastatic lesions often exhibit a similar epithelial-like state to that of the primary tumour, in particular, by forming carcinoma cell clusters via E-cadherin-mediated junctional complexes. However, the factors enabling mesenchymal-like micrometastatic cells to resume growth and reacquire an epithelial phenotype in the target organ microenvironment remain elusive. In this study, we developed a workflow using image-based cell profiling and machine learning to examine morphological, contextual and molecular states of individual breast carcinoma cells (MDA-MB-231). MDA-MB-231 heterogeneous response to the host organ microenvironment was modelled by substrates with controllable stiffness varying from 0.2kPa (soft tissues) to 64kPa (bone tissues). We identified 3 distinct morphological cell types (morphs) varying from compact round-shaped to flattened irregular-shaped cells with lamellipodia, predominantly populating 2-kPa and >16kPa substrates, respectively. These observations were accompanied by significant changes in E-cadherin and vimentin expression. Furthermore, we demonstrate that the bone-mimicking substrate (64kPa) induced multicellular cluster formation accompanied by E-cadherin cell surface localisation. MDA-MB-231 cells responded to different substrate stiffness by morphological adaptation, changes in proliferation rate and cytoskeleton markers, and cluster formation on bone-mimicking substrate. Our results suggest that the stiffest microenvironment can induce MET.

Developing Novel Fabrication and Optimisation Strategies on Aggregation-Induced Emission Nanoprobe/Polyvinyl Alcohol Hydrogels for Bio-Applications.

The current study describes a new technology, effective for readily preparing a fluorescent (FL) nanoprobe-based on hyperbranched polymer (HB) and aggregation-induced emission (AIE) fluorogen with high brightness to ultimately develop FL hydrogels. We prepared the AIE nanoprobe using a microfluidic platform to mix hyperbranched polymers (HB, generations 2, 3, and 4) with AIE (TPE-2BA) under shear stress and different rotation speeds (0-5 K RPM) and explored the FL properties of the AIE nanoprobe. Our results reveal that the use of HB generation 4 exhibits 30-times higher FL intensity compared to the AIE alone and is significantly brighter and more stable compared to those that are prepared using HB generations 3 and 2. In contrast to traditional methods, which are expensive and time-consuming and involve polymerization and post-functionalization to develop FL hyperbranched molecules, our proposed method offers a one-step method to prepare an AIE-HB nanoprobe with excellent FL characteristics. We employed the nanoprobe to fabricate fluorescent injectable bioadhesive gel and a hydrogel microchip based on polyvinyl alcohol (PVA). The addition of borax (50 mM) to the PVA + AIE nanoprobe results in the development of an injectable bioadhesive fluorescent gel with the ability to control AIEgen release for 300 min. When borax concentration increases two times (100 mM), the adhesion stress is more than two times bigger (7.1 mN/mm2) compared to that of gel alone (3.4 mN/mm2). Excellent dimensional stability and cell viability of the fluorescent microchip, along with its enhanced mechanical properties, proposes its potential applications in mechanobiology and understanding the impact of microstructure in cell studies.

Understanding the tumor microenvironment for effective immunotherapy.

Advances in immunotherapy have led to durable and long-term benefits in a subset of patients across a number of solid tumor types. Understanding of the subsets of patients that respond to immune checkpoint inhibitors at the cellular level, and in the context of their tumor microenvironment (TME) is becoming increasingly important. The TME is composed of a heterogeneous milieu of tumor and immune cells. The immune landscape of the TME can inhibit or promote tumor initiation and progression; thus, a deeper understanding of tumor immunity is necessary to develop immunotherapeutic strategies. Recent developments have focused on characterizing the TME immune contexture (type, density, and function) to discover mechanisms and biomarkers that may predict treatment outcomes. This has, in part, been powered by advancements in spatial characterization technologies. In this review article, we address the role of specific immune cells within the TME at various stages of tumor progression and how the immune contexture determinants affecting tumor growth are used therapeutically.

Mesenchymal stem cells induce PD-L1 expression through the secretion of CCL5 in breast cancer cells.

Various factors in the tumor microenvironment (TME) regulate the expression of PD-L1 in cancer cells. In TME, mesenchymal stem cells (MSCs) play a crucial role in tumor progression, metastasis, and drug resistance. Emerging evidence suggests that MSCs can modulate the immune-suppression capacity of TME through the stimulation of PD-L1 expression in various cancers; nonetheless, their role in the induction of PD-L1 in breast cancer remained elusive. Here, we assessed the potential of MSCs in the stimulation of PD-L1 expression in a low PD-L1 breast cancer cell line and explored its associated cytokine. We assessed the expression of MSCs-related genes and their correlation with PD-L1 across 1826 breast cancer patients from the METABRIC cohort. After culturing an ER+/differentiated/low PD-L1 breast cancer cells with MSCs conditioned-medium (MSC-CM) in a microfluidic device, a variety of in-vitro assays was carried out to determine the role of MSC-CM in breast cancer cells' phenotype plasticity, invasion, and its effects on induction of PD-L1 expression. In-silico analysis showed a positive association between MSCs-related genes and PD-L1 expression in various types of breast cancer. Through functional assays, we revealed that MSC-CM not only prompts a phenotype switch but also stimulates PD-L1 expression at the protein level through secretion of various cytokines, especially CCL5. Treatment of MSCs with cytokine inhibitor pirfenidone showed a significant reduction in the secretion of CCL5 and consequently, expression of PD-L1 in breast cancer cells. We concluded that MSCs-derived CCL5 may act as a PD-L1 stimulator in breast cancer.

Simple-to-Operate Approach for Single Cell Analysis Using a Hydrophobic Surface and Nanosized Droplets.

Microfluidics-based technologies for single-cell analysis are becoming increasingly important tools in biological studies. With the increasing sophistication of microfluidics, cellular barcoding techniques, and next-generation sequencing, a more detailed picture of cellular subtype is emerging. Unfortunately, the majority of the methods developed for single-cell analysis are high-throughput and not suitable for rare cell analysis as they require a high input cell number. Here, we report a low-cost and reproducible method for rare single-cell analysis using a highly hydrophobic surface and nanosized static droplets. Our method allows rapid and efficient on-chip single-cell lysis and subsequent collection of genetic materials in nanoliter droplets using a micromanipulator or a laboratory pipette before subsequent genetic analysis. We show precise isolation of single cancer cells with high purity using two different strategies (i- cytospin and ii- static droplet array) for subsequent RNA analysis using droplet digital polymerase chain reaction (PCR) and real-time PCR. Our highly controlled isolation method opens a new avenue for the study of subcellular functional mechanisms, enabling the identification of rare cells of potential functional or pathogenic consequence.

Characterizing the effect of substrate stiffness on the extravasation potential of breast cancer cells using a 3D microfluidic model.

Different biochemical and biomechanical cues from tumor microenvironment affect the extravasation of cancer cells to distant organs; among them, the mechanical signals are poorly understood. Although the effect of substrate stiffness on the primary migration of cancer cells has been previously probed, its role in regulating the extravasation ability of cancer cells is still vague. Herein, we used a microfluidic device to mimic the extravasation of tumor cells in a 3D microenvironment containing cancer cells, endothelial cells, and the biological matrix. The microfluidic-based extravasation model was utilized to probe the effect of substrate stiffness on the invasion ability of breast cancer cells. MCF7 and MDA-MB-231 cancer cells were cultured among substrates with different stiffness which followed by monitoring their extravasation capability through the microfluidic device. Our results demonstrated that acidic collagen at a concentration of 2.5 mg/ml promotes migration of cancer cells. Additionally, the substrate softening resulted in up to 46% reduction in the invasion of breast cancer cells. The substrate softening not only affected the number of extravasated cells but also reduced their migration distance up to 53%. We further investigated the secreted level of matrix metalloproteinase 9 (MMP9) and identified that there is a positive correlation between substrate stiffening, MMP9 concentration, and extravasation of cancer cells. These findings suggest that the substrate stiffness mediates the cancer cells extravasation in a microfluidic model. Changes in MMP9 level could be one of the possible underlying mechanisms which need more investigations to be addressed thoroughly.

Miniature auto-perfusion bioreactor system with spiral microfluidic cell retention device.

Medium perfusion is critical in maintaining high cell concentration in cultures. The conventional membrane filtration method for medium exchange has been challenged by the fouling and clogging of the membrane filters in long-term cultures. In this study, we present a miniature auto-perfusion system that can be operated inside a common-size laboratory incubator. The system is equipped with a spiral microfluidic chip for cell retention to replace conventional membrane filters, which fundamentally overcomes the clogging and fouling problem. We showed that the system supported continuous perfusion culture of Chinese hamster ovary (CHO) cells in suspension up to 14 days without cell retention chip replacement. Compared to daily manual medium change, 25% higher CHO cell concentration can be maintained at an average auto-perfusion rate of 196 ml/day in spinner flask at 70 ml working volume (2.8 VVD). The auto-perfusion system also resulted in better cell quality at high concentrations, in terms of higher viability, more uniform and regular morphology, and fewer aggregates. We also demonstrated the potential application of the system for culturing mesenchymal stem cells on microcarriers. This miniature auto-perfusion system provides an excellent solution to maintain cell-favorable conditions and high cell concentration in small-scale cultures for research and clinical uses.

The role of vitamin D in the age of COVID-19: A systematic review and meta-analysis.

BACKGROUND: Evidence recommends that vitamin D might be a crucial supportive agent for the immune system, mainly in cytokine response regulation against COVID-19. Hence, we carried out a systematic review and meta-analysis in order to maximise the use of everything that exists about the role of vitamin D in the COVID-19. METHODS: A systematic search was performed in PubMed, Scopus, Embase and Web of Science up to December 18, 2020. Studies focused on the role of vitamin D in confirmed COVID-19 patients were entered into the systematic review. RESULTS: Twenty-three studies containing 11 901 participants entered into the meta-analysis. The meta-analysis indicated that 41% of COVID-19 patients were suffering from vitamin D deficiency (95% CI, 29%-55%), and in 42% of patients, levels of vitamin D were insufficient (95% CI, 24%-63%). The serum 25-hydroxyvitamin D concentration was 20.3 ng/mL among all COVID-19 patients (95% CI, 12.1-19.8). The odds of getting infected with SARS-CoV-2 are 3.3 times higher among individuals with vitamin D deficiency (95% CI, 2.5-4.3). The chance of developing severe COVID-19 is about five times higher in patients with vitamin D deficiency (OR: 5.1, 95% CI, 2.6-10.3). There is no significant association between vitamin D status and higher mortality rates (OR: 1.6, 95% CI, 0.5-4.4). CONCLUSION: This study found that most of the COVID-19 patients were suffering from vitamin D deficiency/insufficiency. Also, there is about three times higher chance of getting infected with SARS-CoV-2 among vitamin-D-deficient individuals and about five times higher probability of developing the severe disease in vitamin-D-deficient patients. Vitamin D deficiency showed no significant association with mortality rates in this population.

An easy-to-operate method for single-cell isolation and retrieval using a microfluidic static droplet array.

In-depth study of cellular heterogeneity of rare cells (e.g. circulating tumour cells (CTCs) and circulating foetal cells (CFCs)) is greatly needed in disease management but has never been completely explored due to the current technological limitations. We have developed a retrieval method for single-cell detection using a static droplet array (SDA) device through liquid segmentation with almost no sample loss. We explored the potential of using SDA for low sample input and retrieving the cells of interest using everyday laboratory equipment for downstream molecular analysis. This single-cell isolation and retrieval method is low-cost, rapid and provides a solution to the remaining challenge for single rare cell detection. The entire process takes less than 15 min, is easy to fabricate and allows for on-chip analysis of cells in nanolitre droplets and retrieval of desired droplets. To validate the applicability of our device and method, we mimicked detection of single CTCs by isolating and retrieving single cells and perform real-time PCR on their mRNA contents.

Affibody Functionalized Beads for the Highly Sensitive Detection of Cancer Cell-Derived Exosomes.

Exosomes belong to the class of extracellular vesicles of endocytic origin, which are regarded as a promising source of cancer biomarkers in liquid biopsy. As a result, an accurate, sensitive, and specific quantification of these nano-sized particles is of significant importance. Affinity-based approaches are recognized as the most valuable technique for exosome isolation and characterization. Indeed, Affibody biomolecules are a type of protein scaffold engineered with small size and enjoy the features of high thermal stability, affinity, and specificity. While the utilization of antibodies, aptamers, and other biologically active substances for exosome detection has been reported widely, there are no reports describing Affibody molecules' usage for exosome detection. In this study, for the first time, we have proposed a novel strategy of using Affibody functionalized microbeads (AffiBeads) for exosome detection with a high degree of efficiency. As a proof-of-concept, anti-EGFR-AffiBeads were fabricated and applied to capture and detect human lung A549 cancer cell-derived EGFR-positive exosomes using flow cytometry and fluorescent microscopy. Moreover, the capture efficiency of the AffiBeads were compared with its counterpart antibody. Our results showed that the Affibody probe had a detection limit of 15.6 ng exosomes per mL (~12 exosomes per AffiBead). The approach proposed in the current study can be used for sensitive detection of low expression level markers on tumor-derived exosomes, providing a basis for early-stage cancer diagnosis.

Lung-on-a-chip: the future of respiratory disease models and pharmacological studies.

Recently, organ-on-a-chip models, which are microfluidic devices that mimic the cellular architecture and physiological environment of an organ, have been developed and extensively investigated. The chips can be tailored to accommodate the disease conditions pertaining to many organs; and in the case of this review, the lung. Lung-on-a-chip models result in a more accurate reflection compared to conventional in vitro models. Pharmaceutical drug testing methods traditionally use animal models in order to evaluate pharmacological and toxicological responses to a new agent. However, these responses do not directly reflect human physiological responses. In this review, current and future applications of the lung-on-a-chip in the respiratory system will be discussed. Furthermore, the limitations of current conventional in vitro models used for respiratory disease modeling and drug development will be addressed. Highlights of additional translational aspects of the lung-on-a-chip will be discussed in order to demonstrate the importance of this subject for medical research.

Diagnostic value of serum HER2 levels in breast cancer: a systematic review and meta-analysis.

BACKGROUND: Measurement of serum human epidermal growth factor receptor-2 (HER-2/neu) levels might play an essential role as a diagnostic/screening marker for the early selection of therapeutic approaches and predict prognosis in breast cancer patients. We aimed to undertake a systematic review and meta-analysis focusing on the diagnostic/screening value of serum HER-2 levels in comparison to routine methods. METHODS: We performed a systematic search via PubMed, Scopus, Cochrane-Library, and Web of Science databases for human diagnostic studies reporting the levels of serum HER-2 in breast cancer patients, which was confirmed using the histopathological examination. Meta-analyses were carried out for sensitivity, specificity, accuracy, area under the ROC curve (AUC), positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR). RESULTS: Fourteen studies entered into this investigation. The meta-analysis indicated the low sensitivity for serum HER2 levels (Sensitivity: 53.05, 95%CI 40.82-65.28), but reasonable specificity of 79.27 (95%CI 73.02-85.51), accuracy of 72.06 (95%CI 67.04-77.08) and AUC of 0.79 (95%CI 0.66-0.92). We also found a significant differences for PPV (PPV: 56.18, 95%CI 44.16-68.20), NPV (NPV: 76.93, 95%CI 69.56-84.31), PLR (PLR: 2.10, 95%CI 1.69-2.50) and NLR (NLR: 0.58, 95%CI 0.44-0.71). CONCLUSION: Our findings revealed that although serum HER-2 levels showed low se nsitivity for breast cancer diagnosis, its specificity, accuracy and AUC were reasonable. Hence, it seems that the measurement of serum HER-2 levels can play a significant role as a verification test for initial negative screening test results, especially in low-income regions due to its cost-effectiveness and ease of implementation.

Fabrication of unconventional inertial microfluidic channels using wax 3D printing.

Inertial microfluidics has emerged over the past decade as a powerful tool to accurately control cells and microparticles for diverse biological and medical applications. Many approaches have been proposed to date in order to increase the efficiency and accuracy of inertial microfluidic systems. However, the effects of channel cross-section and solution properties (Newtonian or non-Newtonian) have not been fully explored, primarily due to limitations in current microfabrication methods. In this study, we overcome many of these limitations using wax 3D printing technology and soft lithography through a novel workflow, which eliminates the need for the use of silicon lithography and polydimethylsiloxane (PDMS) bonding. We have shown that by adding dummy structures to reinforce the main channels, optimizing the gap between the dummy and main structures, and dissolving the support wax on a PDMS slab to minimize the additional handling steps, one can make various non-conventional microchannels. These substantially improve upon previous wax printed microfluidic devices where the working area falls into the realm of macrofluidics rather than microfluidics. Results revealed a surface roughness of 1.75 µm for the printed channels, which does not affect the performance of inertial microfluidic devices used in this study. Channels with complex cross-sections were fabricated and then analyzed to investigate the effects of viscoelasticity and superposition on the lateral migration of the particles. Finally, as a proof of concept, microcarriers were separated from human mesenchymal stem cells using an optimized channel with maximum cell-holding capacity, demonstrating the suitability of these microchannels in the bioprocessing industry.