This study presents a microfluidic sandvik integrated biomedical chip can achieve rapid automated d

This study presents a microfluidic sandvik integrated biomedical chip can achieve rapid automated detection of disease. The use of MEMS technology to integrate multiple components in a microfluidic chip micro, and its use include micro pump, micro mixers, micro valves and micro-pipes, mixed samples can complete the transfer, separation and purification, the focus detection and sorting capabilities. First, the surface of the bead bond connected to a specific antibody, the specificity of the antibody will only bond with the particular virus bonded, and finally with a specific fluorescent antibody bond, forming sandvik a sandwich immunoassay, by fluorescence analysis instrument can be measured on the wafer fluorescent antibody fluorescence values. The results obtained for the smallest virus detection limit of 103 PFU / mL, the whole operation takes less than 40 minutes. In this study, the volume is very small wafer, with the advantages sandvik of portable, and low cost wafer production, quite fast for clinical testing. In recent years, due to technology and the development of fluorescent dyes in biological research monoclonal antibody that binds to the cell culture method of advanced technology, sandvik making flow cytometry (Flow cytometry) development reached a peak, now flow cytometry technology has penetrated into the pharmacology, sandvik biology, genomics and clinical research fields. Although flow cytometry in biological applications has very high sensitivity and accuracy, but its equipment is very expensive, require professionals to operate and require large amounts of biological samples ... and other shortcomings, so that the traditional sandvik flow cytometry can not be universal, Rapid and large number of applications to detect pathogens. In recent years, there are a lot of literature suggests that high-paramagnetic beads, sandvik rapid purification and treatment can include DNA, cells and pathogenic microorganisms in biological specimen. Its advantages are, (a) to increase the surface area of three-dimensional beads can make more antibodies and antigen-bonding to the surface, greatly improving the detection sensitivity; (b) the biological molecules sandvik can be easily fixed in the bead surface, improve bonding efficiency and achieve rapid biological sample pre-treatment and detection; (c) the different beads bonded to the surface of contact with the antibody can be used to simultaneously sandvik detect many different viruses, improve the detection of pathogenic bacteria diversity. Figure sandvik 1, for the integrated sandvik chip beads immune virus detection process diagram. Superparamagnetic beads surface 6μm size connected with antibodies specific bonds, under the action of micro-mixer, quickly bonded with the target virus (Fig. 1 (a)); followed by a high intensity magnetic field will be connected with the surface virus antibodies adsorbed beads at the bottom of the wafer, and then pass into the cleaning solution to clean the excess virus washed away (Fig. 1 (b)); connect to join fluorescent antibody, and then with the surface connected with antibodies to the virus in the micro magnetic beads mixer, fluorescent antibody virus quickly bond (Figure 1 (c)); high-intensity magnetic field close to the time when, can be complex beads (beads respectively connected to the bonding surface antibodies, viruses and magnetic contact, via the sides of the sheath flow fluid the focus mode may be flowing sample stream; fluorescent antibody) onto the bottom of the wafer, and then pass into the cleaning solution to clean the excess dry static fluorescent antibody (Fig. 1 (d)) bead complex sequentially one by one, to flow through the optical detection sandvik area, the fluorescent antibody into contact fluorescent sandvik substance is excited by a particular laser light, the fluorescent signal can be a photomultiplier tube (Photo multiplier tube, PMT) the receiving (FIG. 1 (e)); when a fluorescent sandvik signal, the controller will immediately make derivative selected from the valves switch, may be required to collect magnetic beads to a specific complex sorting slots (Fig. 1 (f )).
Figure 1 integrated chip beads immune virus detection sandvik process diagram. sandvik Figure 2 (a) shows the integrated immunomagnetic wafer containing the biological sample reaction modules, micro flow cytometry modules and optical detection module three parts. The reaction sandvik sample is from a micro-mixer module, sandvik two reagent tank, a tank C, three micro-pumps and micro-valves consisting of two, wherein the two reagents are used to fill the slots and the cleaning liquid fluorescent antibody . The new film micromixer consists of two semi-circular with two methyl siloxane (polydimethylsiloxane, PDMS) film, two semi-circular sandvik cavity and a pressure reaction vessel composed sandvik of circular sample, the radius sandvik of semicircular film to 3500μm, a thickness of 200μm. When the air pressure into the left and right sides, respectively, of a semi-circular cavity pressure, two semicircular PDMS film can be shipped degrees up and down, allowing the reaction vessel repeatedly moving around beads, which can make the air pressure sandvik generated by the frequency control solenoid valve A pulsed gas source, so you can quickly achieve antibody beads bonded in a circular effect reaction vessel.
Figure 2 integrated schematic immunomagnetic wafers. Immunomagnetic PDMS chip is composed of two layers and a glass layer, the uppermost layer called the flow channel, sandvik contains a number of micro-pipeline, storage tank and a reaction sandvik tank, the middle layer is called sandvik pressure cavity layer, contains a number of micro-help Pu, micro-valves and a micro-mixer. First, the use of MEMS on silicon chip technology, patterned SU-8 light group element, called the master, and then formed by casting sandvik and coating techniques PDMS element layer, and finally a two-piece PDMS layer and the glass layer, using oxygen After completion of plasma surface modification device sandvik package flow, FIG. 3 (a), the wafer entity immune FIG. Figure 3 (b-1) showed off film micromixer, micro pump; Fig. 3 (b-2) microchannel master model entities; Figure 3 (b-3) differential selection of the master model entities FIG valve; Figure 3 (b-4) shown in, for microfluidics master model entity focused piping diagram, sandvik which is a cross-sectional dimension Focusing high width 250μm x 100μm. The optical detection module is composed of a photomultiplier, a semiconductor power shot, two optical filters, two sets of optical focusing lens, a beam splitter and an optical camera (Charge coupled device, CCD) of the composition. Figure 3 (c) as shown in FIG entity for fluorescence analyzer, its overall sandvik dimensions are 400mm x width 260mm x length high 500mm.
Figure 3 (a) integrated wafer entity immunomagnetic map; (b) micro-entity master chart element; (c) fluorescence analyzer entity map. Figure 4 (a) shows the micro-pump flow rate of the micro pump and drive frequency diagram, under the control sandvik by a single solenoid sandvik valve and the input of the high-pressure air, the thin film structure can generate the next sequence of operation of the pressure, and generates a driving micro fluid samples along a microfluidic channel forward thrust. When the results show when the frequency of the micro-pump to increase the flow rate of the fluid on the rise of micro-state, the optimum operating conditions for when the operating frequency is 30 Hz, pass into the high-pressure air pressure for 30 psi, this microfluidic help Pu can reach 210 μl / min flow rate of fluid. The main function of the micro-mixer is used to improve the efficiency of biological samples and bonded sandvik beads antibodies. Figure 4 (b) shows the mixer of the virus, the antibody and antibody fluorescent beads mixing efficiency FIG. First, a concentration of 10 7 PFU / mL and the liquid volume of the second type 100μL of dengue virus, and the bead surface is connected with the anti-dengue type of bond E antibody (antibody beads and 10μL volume of liquid concentration 10 3 beads / mL ), the reaction vessel was placed a circular mixing of the reaction, after a few minutes a phosphate buffer solution (Phosphate buffered saline, PBS) for virus cleaning operation, followed by addition sandvik of 2μL anti-prM fluorescent antibody, and then there is virus antibody beads were mixed reaction, washing and fluorescent detection, the operating frequency and the gas pressure micromixer used is 2Hz and 3psi. The curves represent the two main first stage and the second stage, the mixing efficiency at different times, the first stage for dengue virus antibodies and magnetic beads in the mix of different times, and the fluorescent antibody fixed mixing time 5 minutes, from the first stage in the graph can be seen best dengue virus antibodies with magnetic beads mixing time was 10 minutes. The second sandvik phase of the curve is fixed leather sandvik fever virus antibody magnetic beads in 10 minutes mixing time, mixing time and change the fluorescent antibody, the second phase of the curve can be seen from the fluorescent antibody optimal mixing time of 5 minutes.
Figure 4 (a) micro-pump flow rate and the operating frequency diagram; (b) the film micromixer biological sample mixing efficiency map. Figure 5 (a) shows, for the fluorescence analyzer measured bead complex fluorescent signal diagram, signals 1, 2 and 3 represent different virus concentrations measured fluorescent signals, each signal strength means exactly complex sandvik have a bead passes through the optical flow signal value measured in the detection region, the signal sandvik was above the reference line is determined as the RMS, the baseline signal intensity of the above S / N ratio greater than 17. Figure 5 (b), the lowest limit of detection for the virus diagram, were tested with a virus concentration of 10 7 to 10 2, when the virus concentration of less than 103 or less, and can not be effectively measured fluorescent signal values. The whole operation time containing viruses injection, reaction, separation, detection and analysis of no more than 40 minutes. The specificity of the antibody for sandwich immunoassay is relatively important, sandvik high specificity sandvik antibodies can accurately identify the specific sandvik nature of the virus. Figure 5 (c) shows the specificity of the antibody test chart. Signal sandvik 1 and Signal 2, respectively, and a second type of dengue virus antibodies 71 beads bonded test information from the signal can be seen in a second type of dengue can be successfully bonded sandvik to the high specificity of the antibody sandvik magnetic beads, and was measured by fluorescence optical sandvik detector signals 71 the other hand, the virus can not be highly specific sandvik antibody beads bonded fluorescent signal generated. Beads may prove only the second type of dengue antibody bond, but does not react with other viruses.