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Typical forms of a combination of electrowetting-on-dielectric (EWOD) technology with sensing and other microfluidic manipulation techniques are reviewed from a technical perspective, including the purposes, significance, and biomedical applications.

Liver is the foremost organ of human being for drug metabolism, and it played a significant role in toxicity evaluation of drugs. Establishing a liver model in vitro can accelerate the process of the drug screening and new drug research and development. We provide a 3D printing based hepatic sinusoid-on-a-chip microdevice that reconstitutes organ-level liver functions to create a drug screening model of toxicity evaluation on chip. The microfluidic device, which recapitulates the hepatic sinusoid microenvironment, consists of PET polyporous membranes which mimic the perisinusoidal space, and experience fluid flow to mimic the hepatic arterial capillaries. The PET membrane was used to separate the hepatocyte and endotheliocyte. The endotheliocyte was cultured on the downside of the membrane and the hepatocyte were 3D seeded on the membrane via the 3D printer. This device was used to reproduce the in vitro liver model for drug toxicity assays. The expression of several biomarkers of liver was compared with the monoculture and 2D cultured conditions, and the results reveal that this organ-on-a-chip microdevice mimics the drug hepatoxicity that has not been possible by 2D cell-based and animal models, providing a useful platform for screening the drugs and developing an effective therapy in hepatopathy.

Blood–brain barrier on a chip (BBBoC) has emerged as a promising tool for high-throughput screening of central nervous system drugs. During the drug screening, it is essential to ensure high repeatability and consistency of assays in different culture units or chips with the same structures. For the assembled chip, cells are introduced into the inoculating chamber by perfusion. However, this method leads to differences between BBBoC because of the uncontrollable flow and sedimentation of the cell suspension in initial stages of cell inoculating. In this work, an inoculating-first and assembling-later method was presented to overcome the shortcoming. First, a porous membrane fixed between the PDMS brackets was made to support the cells. Then human brain microvascular endothelial cells and human astrocytes were respectively inoculated in turn onto the two sides of the porous membrane. When cells grew and occupied the porous membrane, the cell support was sandwiched between two glass substrates with microelectrodes for TEER detection. The method ensured high consistency of cell inoculating number on the porous membrane. Subsequently, a blood-brain barrier model in vitro with high trans-endothelial electrical resistance (TEER) value and expression of ZO-1 was achieved.

When dealing with infectious pathogens, the point-of-care screening and diagnosis strategy should be low-cost, simple, rapid and accurate. Here, we report a multifunctional rapid PCR platform allowing both simultaneous screening of suspected cases and accurate identification and quantification of the virus. Based on the platform, samples suspected of being infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are screened first, after which subsequent precise quantification of the virus (SARS-CoV-2) can be performed if necessary. This fast screening technique offers a detection limit of 10 nucleic acid copies per test during the entire running time of 15 minutes, with a throughput of 9 samples at a time. Besides, depending on a droplet microfluidic chip, this platform could also provide assays of nucleic acids across four orders of magnitude of concentration within less than 15 minutes. Additionally, we successfully use the platform to quickly distinguish between positive and negative cases in clinical samples and rapidly quantify the viral load in each sample, which is consistent with standard RT-qPCR tests. As such, we demonstrate a promising and versatile rapid PCR platform for point-of-care diagnosis of infectious diseases.

Fluorescent silicon nanoparticles (SiNPs) exhibiting excellent photostability and colloidal stability and favorable biocompatibility are emerging as novel fluorescent nanoprobes for biological and biomedical imaging. However, studies on the synthesis of highly bright SiNPs and their specific targeted biolabeling are still limited. Herein, we report a facile one-pot hydrothermal approach for the synthesis of ultrabright SiNPs, in which N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAMO) molecules and trisodium citrate acted as silicon precursor and reducing agents, respectively. Remarkably, the prepared SiNPs were small (~ 3.5 nm diameter) and showed ultrahigh photoluminescence quantum yield of 85.2% and long-term stability (in pH range of 4–13 and almost saturated NaCl solution, and at 80 °C). The low cytotoxicity of the resultant SiNPs facilitated conjugation with biomolecules such as folic acid (FA) for bioimaging. The FA-conjugated SiNPs specifically bound receptor-positive HepG2 cells over receptor-negative A549 cells, indicating the potential of these SiNPs as robust bioprobe both in vitro and in vivo.

In vitro human blood-brain barrier (BBB) model is amenable to cellular studies on pathological and drug transport mechanisms related to the central nervous system (CNS). Compared with animal model of human, micro BBB ( $\mu \text{BBB}$ ) based on microfluidic chips is closer to in vivo phenotype and is more reproducible. Porous semipermeable membranes are integral components of the chip model, which provide cellular interfaces and help establish barrier models. This study proposes a convenient and low-cost fabrication method for ultra-thin micro-porous poly(dimethylsiloxane) (PDMS) membrane, which is inspired by paraffin section technique in immunohistochemistry. Microporous PDMS was obtained from the cured emulsion of PDMS pre-polymer containing uniformly dispersed micro-droplets of water. Cured microporous PDMS was embedded in paraffin to enhance the hardness and then sliced into membrane with a paraffin slicing machine. The minimum thickness of the membrane is $10\ \mu \mathrm{m}$ and smallest pore of $1\ \mu \mathrm{m}$ . The pore size and porosity of the membrane can be adjusted by controlling the water content and mixing time. To prove proof-of-concept, the immortalized human cerebral microvascular endothelial cell line (hCMEM/D3) was seeded on the membrane in a BBB-on-chip. This method provides a potential solution to simply prepare customized PDMS membranes for researchers in biomedical laboratory without micromanufacturing equipment.

The diagnosis of Alzheimer's disease (AD) at early stage is urgent for the clinical treatment. However, the methods of detecting multiple AD related markers with noninvasive sampling are still limited, which hinders their wide applications among potential patients. Here, we present a microfluidic chip with capture arrays to isolate and analyze immunomagnetic beads conjugated with AD salivary biomarkers. Through the design of a three-stage microfluidic capture array, magnetic beads combined with different biomarkers can captured at corresponding sections for high-resolution characterization. Finite element simulation was used to validate the capture efficiency. The lactoferrin with concentration comparable to AD patients was effectively analyzed using the fabricated microfluidic chip. These results indicate the proposed platform to be a potential non-invasive method to detect multiple AD markers by one-time injection of saliva samples with high sensitivity.

Exosomes have now received increasing focus as a promising biomarker for cancer diagnostics because of its specific biocomponents (including proteins, mRNA and lncRNA et al) acquired from parental cells. However, efficiently isolation and quantitative analysis of tumor-related exosomal nucleic acid is still in urgent need. Here, we present an integrated exosome processing microfluidic platform which combines exosome on-chip isolation and sensitive exosomal RNA analysis through droplet digital polymerase chain reaction (ddPCR). Utilizing our system, samples from cell line supernatant could be rapidly detected and demonstrated remarkable detection signals. Owning to advantages including highly sensitive, pollution-free, high-volume (~ 25 µl), low cost and easy handling, our microfluidic system offers a promising means for early cancer diagnosis and prognosis in the era of liquid biopsy.

Liver is the foremost organ of human being for drug metabolism, and it played a significant role in toxicity evaluation of drugs. Establishing a liver model in vitro can accelerate the process of the drug screening and new drug research and development. We provide a 3D printing based hepatic sinusoid-on-a-chip microdevice that reconstitutes organ-level liver functions to create a drug screening model of toxicity evaluation on chip. The microfluidic device, which recapitulates the hepatic sinusoid microenvironment, consists of PET polyporous membranes which mimic the perisinusoidal space, and experience fluid flow to mimic the hepatic arterial capillaries. The PET membrane was used to separate the hepatocyte and endotheliocyte. The endotheliocyte were cultured on the down side of the membrane and the hepatocyte were 3D seeded on the membrane via the 3D printer. This device was used to reproduce the in vitro liver model for drug screening. The expression of several biomarkers of liver were compared with the monoculture and 2D cultured conditions, and the results reveal that this organ-on-a-chip microdevice mimics the drug hepatoxicity that has not been possible by 2D cell-based and animal models, providing a useful platform for screening the drugs and developing an effective therapy in hepatopathy.

We report the first combination of droplet digital and rapid PCR techniques for efficient, accurate, and quantitative detection of SARS-CoV-2 RNA. The presented rapid digital PCR system simultaneously detects two specific targets (ORF1ab and N genes) and one reference gene (RNase P) with a single PCR thermal cycling period around 7 s and the total running time less than 5 min. A clear positive signal could be identified within 115 s via the rapid digital RT-PCR, suggesting its efficiency for the end-point detection. In addition, benchmark tests with serial diluted reference samples of SARS-CoV-2 RNA reveal the excellent accuracy of our system (R2>0.99). More importantly, the rapid digital PCR system gives consistent and accurate detection of low-concentration reference samples, whereas qPCR yields Ct values with significant variations that could lead to false-negative results. Finally, we apply the rapid digital PCR system to analyze clinical samples with both positive and control cases, where results are consistent with qPCR test outcomes. By providing similar accuracy with qPCR while minimizing the detection time-consuming and the false-negative tendency, the presented rapid digital PCR system represents a promising improvement on the rapid diagnosis of COVID-19.

Exosomes are lipid-bilayered nanovesicles secreted by cells to mediate intercellular communication. Various kinds of biomolecules involved in exosomes offer non-invasive approaches for detecting or monitoring disease and developing targeted therapeutics. Here, we present an integrated microfluidic exosome isolation and detection system (EXID system) to analyze the abundance of the exosomal PD-L1 protein marker, which is a transmembrane protein expressed by tumors to suppress immune activation of T cells. By incorporating exosome isolation and biomarker labelling and quantification within a single microfluidic chip, our system reduced the total analysis time below 2 h. Using the EXID system, 7 categories of cell lines including cancer cell lines and control samples were profiled, where significant differences in the fluorescence intensity were observed with the limit of detection (LOD) down to 10.76 per microliter. Such noticeable variations in PD-L1 abundance among cancer cell lines highlighted the need of personalized treatments. Furthermore, 16 clinical samples from 7 post-treated cancer patients, 3 prior-treatment patients and 6 healthy controls, are tested, among which differences in sensitivity toward immune response were subsistent. Because the abundance of PD-L1 reflects the sensibility for immune response, our results provide useful guides to design immunotherapy strategies for different types of tumors.

SARS-Cov-2 has erupted across the globe, and confirmed cases of COVID-19 pose a high infection risk. Infected patients typically receive their treatment in specific isolation wards, where they are confined for at least 14 days. The virus may contaminate any surface of the room, especially frequently touched surfaces. Therefore, surface contamination in wards should be monitored for disease control and hygiene purposes. Herein, surface contamination in the ward was detected on-site using an RNA extraction-free rapid method. The whole detection process, from surface sample collection to readout of the detection results, was finished within 45 min. The nucleic acid extraction-free method requires minimal labor. More importantly, the tests were performed on-site and the results were obtained almost in real-time. The test confirmed that 31 patients contaminated seven individual sites. Among the sampled surfaces, the electrocardiogram fingertip presented a 72.7% positive rate, indicating that this surface is an important hygiene site. Meanwhile, the bedrails showed the highest correlation with other surfaces, so should be detected daily. Another surface with high contamination risk was the door handle in the bathroom. To our knowledge, we present the first on-site analysis of COVID-19 surface contamination in wards. The results and applied technique provide a potential further reference for disease control and hygiene suggestions., Graphical abstract Unlabelled Image, Highlights • First report about on-site detection of SARS-CoV-2 in wards • The whole detection process could accomplish within 45 min without nucleic acid extraction. • The presence of SARS-CoV-2 in wards was confirmed by nucleic acid isothermal amplification.

Microspheres coated with specific biomolecules have been broadly employed to detect tumor markers. In this study, we developed a novel microfluidic platform based on pressure difference for the uniform distribution of microspheres and applied this platform for carcinoma-embryonic antigen detection with quantum dots probes. Within our microfluidic device, micropost arrays were designed to ensure that the trapped microspheres formed dot arrays to overcome the shortcomings of clogging and loss of microspheres, which typically occurred in currently used structures for microsphere capture. A sandwich immunoassay for the detection of typical cancer biomarker CEA was successfully performed on the microfluidic device with all reagents reacted together, which led to reduced experimental time and simple operations. As a result, a limit of detection of 0.5 ng/mL for carcinoma-embryonic antigen detection was achieved, and the calibration curve fitted the Langmuir model, which showed high clinical consistency with serum sample detection. To further investigate the performance of our system, trap efficiency and uniform ratio of microfluidic structure, and specificity of the experiment were evaluated and showed good consequences. The proposed microfluidic immunoassay system with advantages of high sensitivity and specificity, reduced time cost, and facile operations, indicates a promising potential in clinical diagnosis.

High sensitive digital polymerase chain reaction (PCR) is one of the novel technology in molecular biology and has become more and more important in the arena of nucleic acid quantification. However, existing digital PCR technologies usually require specialized platform like high sensitive fluorescence microscope or flow cytometer, which has increased the detection costs and limited their further applications. Here we developed a simple and low cost nucleic acid quantification method based on beads, emulsion, amplification, and magnetics (BEAMing), microsphere and microcolumn array chip. We used the streptavidin (SA) modified polystyrene microspheres to capture the biotin covered target beads obtained via BEAMing technology, which could represent the population of target DNA. The microspheres-beads complexes were then collected and trapped in a microcolumn array chip and observed under a normal microscope. Because the number of microspheres-beads complexes had a relationship of coupled Poisson distribution with the number of target DNA, we could easily infer the number of target DNA through counting the number of chip-trapped microspheres. Our method has reduced the costs and lowers down the difficulty of digital PCR technology, which may promote the applications of digital PCR in research and clinical field.

DNA methylation is closely associated with aberrant epigenetic changes. Previous studies have identified various genes associated with non-small cell lung cancer (NSCLC), but the precise combination responsible for its etiology is still debated. The aim of the present study was to select a new set of NSCLC-related genes using methylation-sensitive high-resolution melting. The promoter methylation status of six selected genes, consisting of protocadherin γ subfamily B, 6 (PCDHGB6), homeobox A9 (HOXA9), O6-methylguanine-DNA methyltransferase (MGMT), microRNA (miR)-126, suppressor of cytokine signaling 3 (SOCS3) and Ras association domain family member 5, also termed NORE1A, was evaluated in 54 NSCLC patients. From these samples, genome-wide DNA was extracted and bisulfite conversion was performed along with fluorogenic quantitative polymerase chain reaction to detect methylation values of the six selected promoters. The present results revealed frequent methylation on PCDHGB6, HOXA9 and miR-126, which contrasted with infrequent methylation on MGMT. The results indicated no methylation on either SOCS3 or NORE1A. The sensitivity and specificity of the methylation assessment were 85.2 and 81.5%, respectively, and the analysis results were validated by pyrosequencing. Furthermore, minute comparison of the association between DNA methylation and clinical features was performed. Overall, these results may provide potential information for the development of better clinical diagnostics and more targeted and effective therapies for NSCLC.

Hypermethylation of CpG islands in the promoter region of many tumor suppressor genes downregulates their expression and in a result promotes tumorigenesis. Therefore, detection of DNA methylation status is a convenient diagnostic tool for cancer detection. Here, we reported a novel method for the integrative detection of methylation by the microfluidic chip-based digital PCR. This method relies on methylation-sensitive restriction enzyme HpaII, which cleaves the unmethylated DNA strands while keeping the methylated ones intact. After HpaII treatment, the DNA methylation level is determined quantitatively by the microfluidic chip-based digital PCR with the lower limit of detection equal to 0.52%. To validate the applicability of this method, promoter methylation of two tumor suppressor genes (PCDHGB6 and HOXA9) was tested in 10 samples of early stage lung adenocarcinoma and their adjacent non-tumorous tissues. The consistency was observed in the analysis of these samples using our method and a conventional bisulfite pyrosequencing. Combining high sensitivity and low cost, the microfluidic chip-based digital PCR method might provide a promising alternative for the detection of DNA methylation and early diagnosis of epigenetics-related diseases.

In this work, a real-time assay for highly sensitive, label-free, multiplexed electrical detection of lung cancer biomarkers was developed by using silicon nanowire field-effect (SiNW-FET) devices. Highly responsive SiNW arrays were fabricated using a CMOS-compatible anisotropic self-stop etching technique with mass reproducibility and low cost character. The SiNW nanosensor was integrated with PDMS microfluidic device, which allows rapid analyte delivery, makes the analysis to be conducted using exceedingly small samples and enables potential multiplexed detection. The nanowire arrays allowed highly selective and sensitive multiplexed detection of microRNA (miRNA)−126 and CEA. Due to high surface-to-volume ratio that the nanowire dimensions confer, the detection floor of single molecule was achieved. The potential utility in identifying clinical samples for early diagnosis of cancer was demonstrated by analyzing biomarkers in clinical related samples. The developed nanosensor with capability for multiplexed real-time monitoring of biomarkers with high sensitivity and selectivity in clinically relevant samples is highly attractive for diagnosis and treatment of cancer and other diseases.

// Zule Cheng 1, 2 , Yanan Bai 1, 2 , Ping Wang 1 , Zhenhua Wu 1, 2 , Lin Zhou 1, 2 , Ming Zhong 3 , Qinghui Jin 1 , Jianlong Zhao 1 , Hailei Mao 3 , Hongju Mao 1 1 State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Science, Shanghai 200050, China 2 University of Chinese Academy of Sciences, Beijing 100039, China 3 Departments of Anesthesiology and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China Correspondence to: Jianlong Zhao, email: jlzhao@mail.sim.ac.cn Hailei Mao, email: mao.hailei@zs-hospital.sh.cn Hongju Mao, email: hjmao@mail.sim.ac.cn Keywords: long noncoding RNA, biomarker, diagnosis, early stage lung squamous cell carcinoma, microarray Received: October 20, 2016 Accepted: December 27, 2016 Published: January 05, 2017 ABSTRACT The aberrant expressions of long noncoding RNAs have been reported in numerous cancers, which have facilitated the cancer diagnosis. However, the expression profile of lncRNAs in early stage lung squamous cell carcinoma has not been well discussed. The present study aimed to examine the expression profile of lncRNAs in early stage lung squamous cell carcinoma and identify lncRNA biomarkers for diagnosis. Through high-throughput lncRNA microarray, we screened thousands of aberrantly expressed lncRNAs and mRNAs in early stage lung squamous cell carcinoma tissues compared to their corresponding adjacent nontumorous tissues. Bioinformatics analyses were used to investigate the functions of aberrantly expressed mRNAs and their associated lncRNAs. After that, in order to identify lncRNA biomarkers for early detection, candidate lncRNA biomarkers were selected based on our established filtering pipeline and validated by real-time quantitative polymerase chain reaction on a total of 63 pairs of tumor samples. Five lncRNAs were finally identified which were able to distinguish early stage tumor and normal samples with high sensitivity (92%) and specificity (83%). These results imply that lncRNAs may be powerful biomarker for early diagnosis.

Exosomes play a crucial role in cancer formation and metastasis which are regarded as a prospective target to cancer diagnosis in liquid biopsy. However, researches about isolating and detecting exosomes remain tardy because of the morphology limitations of exosomes. Here we present an integrated on-chip isolation and analysis system for exosome tumor marker detection. Exosomes were isolated with magnetic beads and labelled by quantum dot (QD) probes in the isolation zone, then the exosome-labelled magnetic beads queued uniformly among the micropillar arrays in the analysis zone. Fluorescence intensity detection in our system was performed by measuring and averaging the fluorescence intensity of each single bead, thus experiment results could be more accurate. Fabrication of the chip was simple and low-cost. These advantages certify our system to be a potential non-invasive method for exosome marker detection and cancer diagnosis.

Highlights A bead-based microarray for exosome isolation and multiplexed tumor marker detection was developed.The beads are uniformly trapped and queued among the micropillars in the chip, which can avoid optical interference and enable more accurate test results.The results with different types of lung cancer exosome samples showed distinctive marker expression levels. Electronic supplementary material The online version of this article (10.1007/s40820-019-0285-x) contains supplementary material, which is available to authorized users., Tumor-derived exosomes are actively involved in cancer progression and metastasis and have emerged as a promising marker for cancer diagnosis in liquid biopsy. Because of their nanoscale size, complex biogenesis, and methodological limitations related to exosome isolation and detection, advancements in their analysis remain slow. Microfluidic technology offers a better analytic approach compared with conventional methods. Here, we developed a bead-based microarray for exosome isolation and multiplexed tumor marker detection. Using this method, exosomes are isolated by binding to antibodies on the bead surface, and tumor markers on the exosomes are detected through quantum dot (QD) probes. The beads are then uniformly trapped and queued among micropillars in the chip. This design benefits fluorescence observation by dispersing the signals into every single bead, thereby avoiding optical interference and enabling more accurate test results. We analyzed exosomes in the cell culture supernatant of lung cancer and endothelial cell lines, and different lung cancer markers labeled with three QD probes were used to conduct multiplexed detection of exosome surface protein markers. Lung cancer-derived samples showed much higher (~ sixfold–tenfold) fluorescence intensity than endothelial cell samples, and different types of lung cancer samples showed distinctive marker expression levels. Additionally, using the chip to detect clinical plasma samples from cancer patients showed good diagnostic power and revealed a well consistency with conventional tests for serological markers. These results provide insight into a promising method for exosome tumor marker detection and early-stage cancer diagnosis. Electronic supplementary material The online version of this article (10.1007/s40820-019-0285-x) contains supplementary material, which is available to authorized users.

We propose the first black phosphorus (BP) – fiber optic biosensor for ultrasensitive diagnosis of human neuron-specific enolase (NSE) cancer biomarkers. A novel optical-nano configuration has been exploited by integrating BP nanosheets with a largely tilted fiber grating (BP-TFG), where the BP is bio-functionalized by the poly-L-lysine acting as a critical cross-linker to facilitate bio-nano-photonic interface with extremely enhanced light-matter interaction. BP nanosheets are synthesized by a liquid ultrasonication-based exfoliation and deposited on fiber device by an in-situ layer-by-layer method. The BP-induced optical modulation effects in terms of thickness-tunable feature, polarization-dependence and enhanced light-matter interaction are experimentally investigated. The anti-NSE immobilized BP-TFG biosensor has been implemented to detect NSE biomarkers demonstrating ultrahigh sensitivity with limit of detection down to 1.0 pg/mL, which is 4 orders magnitude lower than NSE cut-off value of small cell lung cancer. The enhanced sensitivity of BP-TFG is 100-fold higher than graphene oxide or AuNPs based biosensors. We believe that BP-fiber optic configuration opens a new bio-nano-photonic platform for the applications in healthcare, biomedical, food safety and environmental monitoring.

Affinity biosensors of interdigitated electrodes have been widely used in cell detection. This research presents a mass-producible and disposable three-dimensional (3D) structure capacitive sensor based on the integrated circuit package lead frames for cell concentration detection. The fully symmetric 3D interdigital electrode structure makes the sensor more homogeneous and sensitive. (3-Aminopropyl) triethoxysilane (APTES) and glutaraldehyde are immobilized onto gold-plated electrodes. By overlaying the microfluidic channels on top, the volume of the solution is kept constant to obtain repeatable measured capacitance values. Moreover, using the upgraded reading and writing functions and circular measurement of the E4980A Data Transfer Program, an automatic multigroup test system is developed. It is shown that the cell concentration and capacitance are inversely correlated, and the cell concentration range of 103&ndash, 106 CFU∙mL&minus, 1 is achieved. In addition, the rate of capacitance change matches that of state-of-the-art biosensors reported. A program is developed to find the optimal voltage and frequency for linear fitting between the capacitance change and cell concentration. Future work will employ machine learning-based data analysis to drug resistance sensitivity test of cell lines and cell survival status.

Carcinoembryonic antigen (CEA) is an important biomarker in cancer diagnosis. Here, we present an efficient, selective lateral-flow immunoassay (LFIA) based on magnetic nanoparticles (MNPs) for in situ sensitive and accurate point-of-care detection of CEA. Signal amplification mechanism involved linking of detection MNPs with signal MNPs through biotin-modified single-stranded DNA (ssDNA) and streptavidin. To verify the effectiveness of this modified LFIA system, the sensitivity and specificity were evaluated. Sensitivity evaluation showed a broad detection range of 0.25-1000ng/ml for CEA protein by the modified LFIA, and the limit of detection (LOD) of the modified LFIA was 0.25ng/ml, thus producing significant increase in detection threshold compared with the traditional LFIA. The modified LFIA could selectively recognize CEA in presence of several interfering proteins. In addition, this newly developed assay was applied for quantitative detection of CEA in human serum specimens collected from 10 randomly selected patients. The modified LFIA system detected minimum 0.27ng/ml of CEA concentration in serum samples. The results were consistent with the clinical data obtained using commercial electrochemiluminescence immunoassay (ECLIA) (p