Showing papers by "Gwo-Bin Lee published in 2012"

Size-Dependent Attenuation of TLR9 Signaling by Gold Nanoparticles in Macrophages

Abstract: Gold nanoparticles (GNPs), which are generally thought to be bio-inert and non-cytotoxic, have become one of the most ideal nanomaterials for medical applications. Once engulfed by phagocytes, the immunological effects of GNPs are still of concern and require detailed investigation. Therefore, this study explored the immunological significance of GNPs on TLR-mediated innate immunity in murine macrophages. GNP causes specific inhibition of TLR9 (CpG oligodeoxynucleotides; CpG-ODNs) signal in macrophages. The impaired CpG-ODN-induced TNF-α production is GNP concentration- and size-dependent in murine Raw264.7 cells: a GNP of 4 nm in size is more potent than a GNP of 11, 19, 35, or 45 nm in size. Consistent with cytokine inhibition, the CpG-ODN-induced phosphorylation of NF-κB and JNK as well as NF-κB activation are suppressed by GNPs. GNPs accumulate in lysosomes after phagocytosis and also increase TLR9-associated lysosomal cathepsin expression and activities, but this is irrelevant to TLR9 inhibition by GNPs in our studies. In addition, GNPs affected TLR9 translocation in response to CpG-ODNs and to phagosomes. Further exploring how GNPs inhibited TLR9 function, we found that GNPs could bind to high-mobility group box-1 (which is involved in the regulation of TLR9 signaling) inside the lysosomes. The current studies demonstrate that size-dependent inhibition of TLR9 function by GNP may be attributed to its binding to high-mobility group box-1.

Screening of Aptamers on Microfluidic Systems for Clinical Applications

Abstract: The use of microfluidic systems for screening of aptamers and their biomedical applications are reviewed in this paper. Aptamers with different nucleic acid sequences have been extensively studied and the results demonstrated a strong binding affinity to target molecules such that they can be used as promising candidate biomarkers for diagnosis and therapeutics. Recently, the aptamer screening protocol has been conducted with microfluidic-based devices. Furthermore, aptamer affinity screening by a microfluidic-based method has demonstrated remarkable advantages over competing traditional methods. In this paper, we first reviewed microfluidic systems which demonstrated efficient and rapid screening of a specific aptamer. Then, the clinical applications of screened aptamers, also performed by microfluidic systems, are further reviewed. These automated microfluidic systems can provide advantages over their conventional counterparts including more compactness, faster analysis, less sample/reagent consumption and automation. An aptamer-based compact microfluidic system for diagnosis may even lead to a point-of-care device. The use of microfluidic systems for aptamer screening and diagnosis is expected to continue growing in the near future and may make a substantial impact on biomedical applications.

Optical Spectrum and Electric Field Waveform Dependent Optically-Induced Dielectrophoretic (ODEP)Micro-Manipulation

Abstract: In the last seven years, optoelectronic tweezers using optically-induced dielectrophoretic (ODEP) force have been explored experimentally with much success in manipulating micro/nano objects. However, not much has been done in terms of in-depth understanding of the ODEP-based manipulation process or optimizing the input physical parameters to maximize ODEP force. We present our work on analyzing two significant influencing factors in generating ODEP force on a-Si:H based ODEP chips: (1) the waveforms of the AC electric potential across the fluidic medium in an ODEP chip based microfluidic platform; and (2) optical spectrum of the light image projected onto the ODEP chip. Theoretical and simulation results indicate that when square waves are used as the AC electric potential instead of sine waves, ODEP force can double. Moreover, numerical results show that ODEP force increases with increasing optical frequency of the projected light on an ODEP chip following the Fermi-Dirac function, validating that the optically-induced dielectrophoresis force depends strongly on the electron-hole carrier generation phenomena in optoelectronic materials. Qualitative experimental results that validate the numerical results are also presented in this paper.

Nervous necrosis virus replicates following the embryo development and dual infection with iridovirus at juvenile stage in grouper.

Abstract: Infection of virus (such as nodavirus and iridovirus) and bacteria (such as Vibrio anguillarum) in farmed grouper has been widely reported and caused large economic losses to Taiwanese fish aquaculture industry since 1979. The multiplex assay was used to detect dual viral infection and showed that only nervous necrosis virus (NNV) can be detected till the end of experiments (100% mortality) once it appeared. In addition, iridovirus can be detected in a certain period of rearing. The results of real-time PCR and in situ PCR indicated that NNV, in fact, was not on the surface of the eggs but present in the embryo, which can continue to replicate during the embryo development. The virus may be vertically transmitted by packing into eggs during egg development (formation) or delivering into eggs by sperm during fertilization. The ozone treatment of eggs may fail to remove the virus, so a new strategy to prevent NNV is needed.

Rapid detection of live methicillin-resistant Staphylococcus aureus by using an integrated microfluidic system capable of ethidium monoazide pre-treatment and molecular diagnosis

Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium resistant to all existing penicillin and lactam-based antimicrobial drugs and, therefore, has become one of the most prevalent antibiotic-resistant pathogens found in hospitals The multi-drug resistant characteristics of MRSA make it challenging to clinically treat infected patients Therefore, early diagnosis of MRSA has become a public-health priority worldwide Conventionally, cell-culture based methodology and microscopic identification are commonly used for MRSA detection However, they are relatively time-consuming and labor-intensive Recently, molecular diagnosis based on nucleic acid amplification techniques, such as polymerase chain reaction (PCR), has been widely investigated for the rapid detection of MRSA However, genomic DNA of both live and dead pathogens can be distinguished by conventional PCR These results thus could not provide sufficient confirmation of an active infection for clinicians In this study, live MRSA was rapidly detected by using a new integrated microfluidic system The microfluidic system has been demonstrated to have 100% specificity to detect live MRSA with S aureus and other pathogens commonly found in hospitals The experimental results showed that the limit of detection for live MRSA from biosamples was approximately 102 CFU/μl In addition, the entire diagnostic protocol, from sample pre-treatment to fluorescence observation, can be automatically completed within 25 h Consequently, this microfluidic system may be a powerful tool for the rapid molecular diagnosis of live MRSA

Integrated microfluidic system for the identification and multiple subtyping of influenza viruses by using a molecular diagnostic approach

Abstract: This study presents an integrated microfluidic system capable of rapid diagnosis of influenza infection and subtyping of influenza viruses. The viral RNA extraction module and reverse-transcription polymerase chain reaction module were integrated with an external optical detection module into the microsystem. Magnetic beads conjugated with specific nucleotide probes were first used to capture target RNA from influenza viral particles after thermolysis/hybridization processes. The hybridized target RNA was purified and collected by an external magnetic field. Finally, the extracted RNA was amplified by one-step RT-PCR products and detected by optical detection module with TaqMan fluorescence system. Moreover, the LOD was experimentally found to be 102 copies for influenza A H1/H3 and influenza B viruses. Experimental results also showed that different subtypes of influenza viruses were diagnosed by using multiplex RT-PCR process and automatically completed within 110 min in the developed microfluidic system.

Manipulation of micro-particles by flexible polymer-based optically-induced dielectrophoretic devices.

Abstract: This study presents a novel technology to manipulate micro-particles with the assistance from flexible polymer-based optically-induced dielectrophoretic (ODEP) devices. Bending the flexible ODEP devices downwards or upwards to create convex or concave curvatures, respectively, enables the more effective separation or collection of micro-particles with different diameters. The travel distances of the polystyrene beads of 40 μm diameter, as induced by the projected light in a given time period was increased by ~100%, which were 43.0 ± 5.0 and 84.6 ± 4.0 μm for flat and convex ODEP devices, respectively. A rapid separation or collection of micro-particles can be achieved with the assistance of gravity because the falling polystyrene beads followed the inclination of the downward and upward bent ODEP devices.

Sample pretreatment and nucleic acid-based detection for fast diagnosis utilizing microfluidic systems.

Abstract: Recently, micro-electro-mechanical-systems (MEMS) technology and micromachining techniques have enabled miniaturization of biomedical devices and systems. Not only do these techniques facilitate the development of miniaturized instrumentation for biomedical analysis, but they also open a new era for integration of microdevices for performing accurate and sensitive diagnostic assays. A so-called “micro-total-analysis-system”, which integrates sample pretreatment, transport, reaction, and detection on a small chip in an automatic format, can be realized by combining functional microfluidic components manufactured by specific MEMS technologies. Among the promising applications using microfluidic technologies, nucleic acid-based detection has shown considerable potential recently. For instance, micro-polymerase chain reaction chips for rapid DNA amplification have attracted considerable interest. In addition, microfluidic devices for rapid sample pretreatment prior to nucleic acid-based detection have also achieved significant progress in the recent years. In this review paper, microfluidic systems for sample preparation, nucleic acid amplification and detection for fast diagnosis will be reviewed. These microfluidic devices and systems have several advantages over their large-scale counterparts, including lower sample/reagent consumption, lower power consumption, compact size, faster analysis, and lower per unit cost. The development of these microfluidic devices and systems may provide a revolutionary platform technology for fast sample pretreatment and accurate, sensitive diagnosis.

A tunable microfluidic-based filter modulated by pneumatic pressure for separation of blood cells

Abstract: This article presents a new microfluidic-based filter for the separation of microbeads or blood cells with a high filtration rate. The device was composed of a circular micropump for automatic liquid transport, and a normally closed valve located at the filter zone for separation of beads or cells. The filtration mechanism was based on the tunable deformation of polydimethylsiloxane (PDMS) membranes that defined the gap between a floating block structure and the substrate which determined the maximum diameter of the beads/cells that can pass through the filter. Another unique feature of this filter is an unclogging mechanism using a suction force, resulting in a back flow to remove any trapped beads/cells in the filter zone when the PDMS membrane was restored to its initial state. The separation performance of the proposed device was first experimentally evaluated by using microbeads. The results showed that this device was capable of providing size-tunable filtration with a high recovery efficiency (95.25–96.21%) for microbeads with sizes smaller than the defined gap in the filter zone. Furthermore, the proposed device was also capable of performing separation of blood cells and blood plasma from human whole blood. Experimental results showed that an optimum filtration rate of 21.40 and 3.00 μl/min correspond to high recovery efficiencies of 86.69 and 80.66%, respectively, for red blood cells (RBCs) and blood plasma. The separation method developed in this work could be used for various point-of-care diagnostic applications involving separation of plasma and blood cells.

Dual-Row Needle Arrays Under an Electromagnetic Thermotherapy System for Bloodless Liver Resection Surgery

Abstract: Electromagnetic thermotherapy has been extensively investigated recently and may become a new surgical modality for a variety of medical applications. It applies a high-frequency alternating magnetic field to heat up magnetic materials inserted within the human body to generate tissue coagulation or cell apoptosis. Using a new procedure with dual-row needle arrays under an electromagnetic thermotherapy system with a feedback temperature control system, this study demonstrates bloodless porcine liver resection, which is challenging using existing methods. In vitro experiments showed that hollowed, stainless-steel needles could be heated up to more than 300°C within 30 s when centered under the induction coils of the electromagnetic thermotherapy system. In order to generate a wide ablation zone and to prevent the dual-row needle arrays from sticking to the tissue after heating, a constant temperature of 120°C was applied using a specific treatment protocol. The temperature distribution in the porcine livers was also measured to explore the effective coagulation area. Liver resection was then performed in Lan-Yu pigs. Experimental results showed that seven pigs underwent liver resection without bleeding during surgery and no complications afterward. The dual-row needle arrays combined with the electromagnetic thermotherapy system are thus shown to be promising for bloodless tissue resection.

An automatic microfluidic system that continuously performs the systematic evolution of ligands by exponential enrichment

Abstract: The systematic evolution of ligands by exponential enrichment (SELEX) technique has been extensively used to screen molecule-specific aptamers from combinatorial libraries of synthetic nucleic acids. Aptamers are single-stranded DNA or RNA, which have a high affinity to a large variety of molecules ranging from small drugs or metabolites to cells. Therefore, they have a variety of promising applications such as for diagnostics and targeted therapeutics. In this study, a new microfluidic chip was developed to perform continuous screening of DNA-based aptamers in an automatic format. When compared with the existing manual procedure, the developed microfluidic chip has several advantages including a rapid and efficient screening process, automation, and less consumption of samples/reagents. Experimental data showed that an aptamer specific to alpha-fetoprotein was successfully screened from a random DNA pool. The entire screening process (five continuous, repetitive rounds) can be completed within 6 h, which is much faster than the traditional methods (more than 15 h). An automatic, rapid and efficient SELEX process was performed by this developed microfluidic chip, which may enable a generalized platform for the fast screening of DNA-based biomarkers in the future.

An automated microfluidic chip system for detection of piscine nodavirus and characterization of its potential carrier in grouper farms.

Abstract: Groupers of the Epinephelus spp. are an important aquaculture species of high economic value in the Asia Pacific region. They are susceptible to piscine nodavirus infection, which results in viral nervous necrosis disease. In this study, a rapid and sensitive automated microfluidic chip system was implemented for the detection of piscine nodavirus; this technology has the advantage of requiring small amounts of sample and has been developed and applied for managing grouper fish farms. Epidemiological investigations revealed an extremely high detection rate of piscine nodavirus (89% of fish samples) from 5 different locations in southern Taiwan. In addition, positive samples from the feces of fish-feeding birds indicated that the birds could be carrying the virus between fish farms. In the present study, we successfully introduced this advanced technology that combines engineering and biological approaches to aquaculture. In the future, we believe that this approach will improve fish farm management and aid in reducing the economic loss experienced by fish farmers due to widespread disease outbreaks.

Inducing self-rotation of Melan-a cells by ODEP

Abstract: This paper presents our discovery that self-rotation of Melan-a pigment cells can be induced by applying appropriate optical dielectrophoretic (ODEP) parameters. Under optically induced DEP force, which is generated by specific optical electrode patterns and with a band-width of AC bias frequencies, Melan-a cells can be trapped or repelled away from the optical electrodes. In addition, the self-rotation motion of the Melan-a cells was observed. In particular, the applied frequency and voltage dominate the overall cell motion. Hence, the cells can be manipulated on an electrode-free surface. This project studies the rotation and translation motions of the cells in an ODEP system. We speculate that the unbalanced distribution of melanin inside the pigment cells causes this self-rotation phenomenon. Therefore, both pigment cells (Melan-a) and non-pigment cells (Raw 264.7) have been tested in the ODEP experiments to compare their motion behavior. Potential applications for this novel observation are to use the self-rotation phenomenon to elucidate the pigment cells' physical property, and separate the pigment and non-pigment cells.

Integrated microfluidic system for HIV detection

Abstract: This study presents a new microfluidic system for molecular diagnosis of human immunodeficiency virus (HIV) infection. In this study, magnetic beads conjugated with nucleotide probes specific to HIV were used to perform purification and enrichment of target DNA. Then an on-chip PCR module was used to perform amplification of four detection genes associated with HIV infection. Finally, an optical module was used to detect the amplified PCR products. Experimental results demonstrated that multiple HIV detection fragments could be amplified successfully and detected on-line using the developed microfluidic system in the HIV-infected cell line within 95 min, which is much faster than the existing methods.

Method for detecting mitochondria gene alterations

Abstract: The present invention relates to a method for detecting mitochondria alterations, which comprises the following steps: (A) providing a separation element and a sample; (B) mixing the separation element and the sample, wherein a detecting sample is obtained through the binding of a DNA fragment on the separation element to mitochondrial DNA in the sample; (C) dividing the detecting sample into a comparison group and a detection group; (D) adding an amplification solution into the comparison group and the detection group respectively to begin a DNA amplified reaction, and further adding a restriction enzyme into the detection group, wherein the amplification solution comprises a labeling reagent and a primer pair; and (E) detecting amounts of the labeling reagent in the comparison group and the detection group respectively after the DNA amplified reaction.

Rapid micro-patterning of a conductive PANI/MWNTs-polymer composite using an optically-induced electrokinetics chip

Abstract: A flexible, dynamically programmable and low-cost method applicable to micro-patterning of a conductive polymer/carbon nanotube composite solution is significant due to the potential applications in many areas. This paper demonstrates a new micro-patterning method for fabricating electrodes from a conductive polyaniline (PANI)/MWNT composite using an optically-induced electrokinetics (OEK) chip. This method quickly patterns flexible polymeric electrodes with different geometries when a square waveform signal with amplitudes from 16-20 Volts and frequencies from 20-30 kHz are applied. The geometric dimensions of the electrodes can be varied dynamically by controlling the size and exposure time of the light pattern. The surface morphology of electrodes patterned by this method is scanned by an atomic force microscope (AFM) and a scanning electron microscope (SEM) which show that the electrodes are uniform and continuous. Furthermore, the geometric dimensions and resistances of the electrodes are measured and analyzed. Experimental results reveal that the relationship between the resistance and geometries of the electrodes obey Ohm's law and the resistivity of the electrodes is about 0.03Ω·m.

An optical diagnostic system using isothermal amplification technique for Phalaenopsis orchids

Abstract: Early detection of pathogens is important for surveillance and control of infectious diseases among Phalaenopsis orchids. Therefore, the current study presents an integrated microfluidic system for rapid and automatic detection of Phalaenopsis orchid viruses. The entire process, including pathogen-specific ribonucleic acid (RNA) purification, nucleic acid amplification using reverse transcription loop-mediated-isothermal-amplification (RT-LAMP) and optical detection by measuring turbidity change, can be automatically performed on a single chip within 65 minutes. This is the first time that an integrated microfluidic system for the detection of Phalaenopsis orchid viruses has been demonstrated. The specificity and sensitivity of the system were also explored in this study to validate its performance. One of the most prevalent orchid viruses, Cymbidium mosaic virus (CymMV), was used in current study to demonstrate the capabilities of the developed system.

An optical-induced platform for multiple genes transfection

Abstract: Gene transfection is an important technology in biological applications. Electroporation is one of gene transfection methods that deliver extracellular genetic materials into cells by using a high electrical field to forming pores on cell surface. However, the high voltage provided by an electroporator may impair cells to survive and cause low efficiency of yield rate. In this study, a new platform was developed for gene transfection under a lower applied voltage by utilizing an optical induced non-uniform electric field. To obtain higher transfection efficiency, a multi-spot optical image was projected to the gene transfection chip, resulting in localized non-uniform electric fields generated from these optical patterns. The experimental results in this study showed that one or more plasmid carried fluorescence genes could be effectively transfected into mammalian cells and the cells successfully expressed foreign proteins by using the developed optical-induced gene transfection platform. Moreover, the transfection efficiency of optical-induced gene transfection platform was significantly higher than the traditional electroporation technology. This developed platform may provide a simpler and more efficient tool for gene transfection.

Pathogen detection from phalaenopsis orchids by using an integrated microfluidic system

Abstract: Early detection of pathogens in high-value agricultural species is crucial. Therefore., many methods which can detect agricultural pathogens to prevent economic loss have been developed. Among them., immunoassays., nucleic acid hybridization and polymerase chain reaction have been demonstrated to detect pathogens in Phalaenopsis orchid successfully with satisfactory sensitivity and specificity. However., above-mentioned methods all have some disadvantages including lengthy process or requiring specialized laboratory facilities and well-trained technicians. The current study therefore presents an integrated micro fluidic system for rapid and automatic detection of pathogens in agricultural species. The entire procedure., including pathogen-specific ribonucleic acid (RNA) purification., nucleic acid amplification using reverse transcription loop-mediated-isothermal-amplification (RT-LAMP) and optical detection., can be automatically performed on a single chip within 65 minutes. Moreover., the detection module can be interchanged between a fluorescent detector and a turbidity detector., depending on the need of the operator. Furthermore., the developed system can detect pathogens directly from fresh agriculture tissues such as leaves and flowers of the Phalaneopsis orchids. This is the first time that an interchangeable integrated micro fluidic system for the detection of Phalaneopsis orchids has been demonstrated. Some of the most prevalent Phalaenopsis orchid pathogens., such as Cymbidium mosaic virus (CymMV) and Tomato spotted wilt virus (TSWV) for Phalaneopsis orchids were used in the current study to demonstrate the capabilities of the developed system. It is concluded that this system with dual detection units can directly detect pathogens from crude agricultural materials successfully.

Micro/Nano Technologies and Their Biological and Medical Applications

Abstract: Recently, biomedical or biological micro/nano electromechanical systems (Bio-MEMS/NEMS) have been extensively explored in a wide variety of biomedical applications. These systems realized by micro/nano fabrication techniques comprising micropumps, microvalves, microfilters, micromixers, microchannels, microsensors, and microreactors are also referred to as micro-total-analytical-systems (μTAS) or lab-on-a-chip (LOC). Crucial processes including sample pretreatment, transportation, reaction, mixing, separation, and detection can be performed on a single chip. Various biosamples such as bloods, urines, cells, pathogens, proteins, DNA, or RNA can be used to perform the processes including cell culture, cell sorting and counting, cell lysis, DNA/RNA extraction, purification, amplification, separation, detection, and pathogen detection. In this chapter, these technologies have been reviewed to demonstrate their important biomedical or biological applications in a variety of fields, such as biological and chemical analysis, point-of-care diagnosis, clinical and forensic analysis, molecular diagnosis, drug discovery, and disease detection.

Enzyme digestion-based microfluidic system for DNA methylation assay

Abstract: Early and accurate diagnosis of cancer plays a very important role in cancer treatment. The DNA methylation of tumor suppressor genes has been used as a diagnostic biomarker of early carcinogenesis. The 5-methylcytosine of CpG islands in the promoter region has been demonstrated as an evidence of DNA methylation. In this study, the entire process for performing DNA methylation assay including capturing of target DNA, HpaII and MspI endonuclease digestion and nucleic acid amplification have been realized in an integrated microfluidic system. The limit of detection in the microfluidic system was experimentally found to be 102 cells/reaction. The entire process from sample loading to results observed only takes 3 hrs. Rapid diagnosis of ovarian cancer cells in the integrated microfluidic system has been demonstrated by using cell lines and clinical samples. The developed micro system may be promising for early diagnosis of cancers.

An integrated microfluidic platform for chromosomal analysis

Abstract: The fluorescence in situ hybridization (FISH) technique has been commonly employed to determine chromosomal abnormalities. However, it still requires lengthy and labor-intensive sample preparation process. In this study, a new microfluidic chip capable of performing the entire FISH protocol automatically was reported. When compared with the traditional method, several advantages including reduced consumption of biosamples and reagents, automation, fast analysis, can be achieved. Experimental data demonstrated that the developed system can successfully provide superior performance for probing the genetic content of cells at the chromosomal abnormality.

Rapid detection of influenza infection with magnetic MnFe 2 O 4 nanoparticle-based immunoassay by using an integrated microfluidic system

Abstract: In this study, new magnetic manganese ferrite (MnFe 2 O 4 ) nanoparticles with a size around 100 nanometer (nm) in diameter were used to improve the performance of an immunoassay for detection of influenza infection. A new microfluidic system was developed to automatically implement the entire detection process. In order to apply these new nanoparticles for influenza detection, the design of the micromixer was optimized to reduce the dead volume. Furthermore, a custom-made control system was used for automating the entire chip operation. The synthesized nanoparticles were tested for three months to confirm the stability of the process of thermal decomposition. Furthermore, with the custom-made control system, mixing index of the modified micromixer can be as high as 96% in 2 seconds under both positive and negative air forces under a driving frequency of 4Hz. The optical signals showed that this nanoparticle-based immunoassay could successfully achieve a limit of detection as low as 0.03 Hau. This developed microfluidic system can automatically perform the entire process involved in the immunoassay, including virus purification and detection, and therefore may provide a promising platform for fast diagnosis of the infectious diseases.

Rapid measurement of AFP using AFP-specific aptamer on a microfluidic chip

Abstract: This study presents a new suction-type microfluidic system capable of rapid measurement of alpha-fetoprotein (AFP) by utilizing magnetic bead-based technologies. Two modules, including a suction-type incubator for the magnetic beads to capture AFP and acridinium ester (AE)-labeled anti-AFP antibodies and a microfluidic control module for sample transportation, were integrated into this microfluidic system. With the incorporation of AFP-specific aptamer-conjugated magnetic beads, the target AFP could be recognized and attracted onto the surface of the magnetic beads from the clinical sample. The entire process including two-step incubation and purification process could be automatically performed within 25 min, which is only about 20% of the time required when using a benchtop machine (for about 130 min). Besides, the total sample and reagent volume consumed is only 105 μL, which is significantly less than that required in a large system (410 μL). More importantly, experimental results showed that clinical human serum samples can also be accurately analyzed. The microfluidic system may be promising for point-of-care applications for AFP detection in the future.

Microfluidic system for rapid detection of influenza infection by utilizing magnetic MnFe 2 O 4 nanoparticle-based immunoassay

Abstract: In this study, new magnetic manganese ferrite (MnFe 2 O 4 ) nanoparticles with a size around 100 nanometer (nm) in diameter were used to improve the performance of an immunoassay for detection of influenza infection. A new microfluidic system was developed to implement the detection process. In order to apply these new nanoparticles for influenza detection, the design of the micromixer was modified to reduce the dead volume. Furthermore, the operating condition for the magnet was optimized such that magnetic MnFe 2 O 4 nanoparticles can be collected in 120 seconds. The optical signals showed this nanoparticle-based immunoassay could successfully distinguish the virus sample from the negative control sample. This developed microfluidic system can automatically perform the entire process involved in the immunoassay, including virus purification and detection, and therefore may provide a promising platform for fast diagnosis of the infectious diseases.