Construction Of Smartphone-based Device And Its Application In Point-of-care Testing

With the rapid development of the Internet,the popularity of connected mobile terminals is growing rapidly.Smartphones have become a high-end mobile device that is inseparable from daily life and work.In recent years,smart phones have become more and more functional,so that their use is not limited to daily life.Researchers have also developed a variety of portable detection devices based on smartphones.This undoubtedly promotes the development of pointof-care test(POCT)analysis based on smartphones.The development of such portable devices depends on this factor.First,because smart phones integrate multiple sensors into one and are widely used and carried in daily life,chemical analysis using the built-in functions of mobile phones can easily perform timely detection without complicated and bulky equipment.This means that smartphones provide a handheld mobile platform for inspection work.Secondly,the built-in camera resolution of mobile phones has always been a selling point of major mobile phone brands.The inside of the camera is a CMOS photoelectric sensor,which makes the builtin camera of the mobile phone not only limited to photographing the shape of the object,it provides a new idea for the detection method related to the photoelectric induction.This research will use the above advantages of smart phones to develop portable detection devices based on smartphones.First,a portable imaging device based on mobile phones was designed and manufactured,which solved the problem of unstable signals in colorimetric analysis based on smartphones and successfully applied it to colorimetric analysis based on microfluidic chips.Secondly,in order to give full play to the role of smartphones in the analysis of microfluidic chips,a portable micro-analysis device has been developed to achieve colorimetric analysis of micron-level samples.Finally,based on the previous design,a spectrum analysis device was introduced,and a portable micro-spectrum analysis device was developed and manufactured to achieve the simultaneous collection of micron-level sample morphology and spectrum.A rotary liquid column chip was manufactured,which used the surface tension and gravity of liquid to pull up tiny droplets.The shape of the liquid column is optimized by controlling the contact area of the upper and lower chips to the liquid,and it is used in conjunction with our portable smartphone-based spectroscopic detection device to achieve the spectral colorimetric analysis of microliquids.The results of the analysis highlight the instant detection capabilities of smartphone-based high-throughput micro-droplet spectroscopic detection chips,providing a new detection method for POCT.The main research contents of this article are as follows:1.Improved analytical performance of smartphone-based colorimetric analysis by using a power-free imaging boxSmartphone-based colorimetric analysis is very suitable for point-of-care testing.However,image quality is often plagued by uneven and non-reproducible illumination,which can negatively affect the accuracy of color analysis.This work proposes an imaging box that uses the smartphone's own light source for illumination,effectively eliminating the interference of ambient light on the analysis.In addition,the partial exposure of the photo will seriously affect the color signal of the sample,thus adversely affecting the results.The device uses a V-shaped light pipe coupled with the light source of the smartphone to direct the vertical light source to both sides of the inner wall of the imaging box,thereby avoiding the partial exposure of the photo due to the mirror image of the light source.The numerical simulation verifies that the light pipe can establish ideal diffuse reflection conditions,and eliminates the specular reflection of the microfluidic chip.In addition,color images of glucose tests performed on paper strips and enzyme-linked immunosorbent assay(ELISA)performed on transparent microchannels were captured and analyzed using the developed imaging cassette.The results show that this device can reduce the measurement difference and increase the minimum detection limit,highlighting the potential of smartphone-based colorimetric analysis systems in real-time inspection applications.2.Smartphone supported backlight illumination and image acquisition for microfluidicbased point-of-care testingThe smartphone-based image analysis system is very beneficial for real-time detection applications.However,because the microfluidic device is highly miniaturized,its microscopic channel can only be clearly observed when zoomed in.In addition,most biological samples are more suitable for detection in transmitted light.In order to solve these problems,this work proposes a micro imaging box,which converts the built-in light source of the smartphone into a uniform backlight illumination source to avoid overexposure interference caused by reflected illumination.By embedding distortion-free lenses in the imaging box,distortion-free magnification of micro samples is achieved.The constructed micro-imaging system based on the smartphone can clearly capture the colorimetric signal of the micro channel with a width of about 25 ?m.Colorimetric signal analysis of trace liquids with different concentrations of proteins was performed by applying BCA standard protein measurement method.In addition,a microfluidic chip for ABO blood typing was manufactured.Using the system to analyze the test results,it was found that a microscopic image of induced coagulation can be clearly observed under a 3 ?L blood sample.These results highlight the potential of smartphone-based micro-imaging devices for instant detection.3.Smartphone-supported portable micro-spectroscopy/imaging system to character morphology and spectra of samples at microscaleThe smartphone-based analysis system is favored for point-of-care testing applications.The present work proposes a novel micro-spectroscopy/imaging system comprising a portable spectrometer as an optical sensor,a compact homemade microscope to acquire the image and spectra of micron-scale regions and a liquid column chip was fabricated for use with our equipment to achieve colorimetric analysis of micro liquids.The ability to obtain morphology and spectra information using the proposed portable device was demonstrated by examining the sub-pixels of a smartphone screen.Protein concentration quantification based on the bicinchoninic acid method was demonstrated with the proposed micro-spectroscopy/imaging system to analyze the spectrometer signals.These results highlight the potential for adopting a smartphone-based micro-spectroscopy/imaging system for point-of-care testing.