Miniaturized Biochemical Analyzers For POCT Of Micro Amounts Of Blood Samples

Clinical biochemical analysis occupies an important position in in vitro diagnosis(IVD),which can reflect the health information through detecting biomarkers related to disease the in human whole blood.Conventional clinical biochemical analyzers with sophisticated structures and high prices mainly exist in the central laboratory of the large or medium-sized hospitals.Priority to test,the large blood samples are required to be centrifuged at a high speed.Therefore,it is not suitable for on-site biochemical analysis and point of care testing(POCT)in resource-limited primary medical institutions.Microfluidic technique,with its advantages of low consumption,automation,miniaturization,and integration,has energized the development of POCT in micro-volume plasma extraction and miniaturized multi-target biochemical analysis.In Chapter One,the basic principles,structure,and method of blood plasma separation systems based on the microfluidic technique are first reviewed.Among them,blood filter membrane has showed its unique advantages in many on-site plasma separation systems.In addition,the microanalytical system based on light absorption principle and the miniaturized and automated commercial biochemical analyzer are subsequently reviewed.In Chapter Two,an integrated biochemical analysis system integrated with a disposable microchip was designed and constructed to meet the requirements of POCT,which contained a micro-liquid manipulation module,a temperature incubation module,and a transmitted light absorption measurement module.The microchip integrated a plasma extraction unit and a biochemical analysis unit.The present system could complete a series of operations including plasma extraction,plasma quantitative dilution,plasma transferring and distribution,biochemical reaction and absorbance measurement.The whole biochemical analysis system(250 mm × 180 mm × 280 mm)controlled by Lab VIEW program could extract up to 10 μL plasma from a single drop of blood within 5 min,and it has finally been successfully applied to the multi-target biochemical analysis such as plasma glucose,cholesterol and total protein in plasma.In Chapter Three,a miniaturized and automated biochemical analyzer was developed for primary medical institutions through redesigning and constructing absorbance measurement module,micro-liquid manipulation module and temperature incubation module based on the previous work.The absorbance measurement module based on the reflected light was constructed combining a Y-shaped optical fiber and a reflective layer made of liquid metal.A self-built integrated micro-syringe pump was used to realize the convenient and reliable micro-liquid manipulation.A xenon lamp and a miniature spectrometer were adopted to reduce the volume and cost of the optical system.This biochemical analyzer(180 mm × 180 mm × 260 mm)showed its advantages of miniaturization,automation and integration through the compact mechanical design and embedded circuit.The system was successfully applied to biochemical analysis of 15 targets including blood glucose and blood lipids,liver and kidney function,and myocardial enzymes in trace amounts of whole blood.