Design,Development And Application Of Adaptive Pressure-driven Microfluidic Chip-based Point-of-care Testing Kits

In Vitro Diagnostic Equipment is gradually developed to two levels: the central laboratory of a large-scale automatic integrated assembly line and the point-of-care testing(POCT)that is fast,low-cost,and not restricted by site and experimental conditions,and does not require complicated processing of samples to be tested.With the popularization and application of POCT products at primary care,the testing technology and service capabilities of grassroots medical institutions have been effectively improved.The current POCT products can almost cover the testing of all clinical testing laboratories,but there is still a certain gap between the accuracy and sensitivity of the existing POCT testing technology and the central laboratory chemiluminescence technology.Along with the iterative updating of POCT technology,clinical departments are increasingly demanding the performance of POCT products,especially for myocardial infarction and abnormal thyroid function markers,which require high performance indicators such as accuracy and sensitivity,and the application of existing POCT routine testing technology still needs to be improved.Microfluidics is attracting more and more attention from clinical departments.Microfluidics refers to the precise handling and manipulation of microfluids in microchannels of tens to hundreds of micrometres in size.According to the driving method of microfluidics,it can be divided into active driving force by a mechanical driving method and passive driving force by a non-mechanical driving method.Since active drive has the advantages of precise and stable microfluidic control,this study took the active drive microfluidic chip as the research object,and carried out the design and development of the basic operating unit components,singleplex and multiplex microfluidic chips,two POCT kits,and the in-depth research on the indicators and clinical applications of those two POCT kits.The content includes the following aspects:(1)The active-driven microfluidic chip relies on external driving force to drive the microfluid in the microfluidic channel of the chip to realize the precise control of the microfluid.In order to better control the microfluid in the active microfluidic chip,the main operating units and components of the chip have been carefully designed and improved according to the characteristics of the active microfluidic chip,resulting in a significant improvement in its detection performance.The single-channel microfluidic chip and the multi-channel microfluidic chip have been designed and developed according to clinical needs for the single-indicator test for cardiac troponin I(c Tn I)and the combined test for the five thyroid function tests respectively.(2)In response to the clinical needs of the tests for myocardial infarction and abnormal thyroid function,we have designed and developed two types of POCT kits of active microfluidic chip that can be used for emergency diagnosis,based on the principle of time-resolved fluorescence immunoassay detection.The two POCT kits are "microfluidic chip-based cardiac troponin I detection kit " and "microfluidic chip-based thyroid function detection kit ".(3)c Tn I is an important indicator used in clinical emergencies to assess myocardial injury and myocardial infarction.The c Tn I microfluidic chip POCT assay kit was prepared by coating anti-human troponin I antibody I / II on the surface of the chip with fluorescent microsphere labeling for the accurate determination of c Tn I in whole blood samples.And the performance indicators such as stability,inter-batch variation,anti-interference,reproducibility and detection limit of the POCT product were evaluated.The results show that the c Tn I microfluidic chip has high specificity,low detection limit and low inter-batch variation,and the assay performance is comparable to that of the Roche electrochemiluminescence immuno-methodology kit,which can be used for the detection and diagnosis of c Tn I in clinical emergencies.(4)Due to the requirement of detection performance of the biomarkers of thyroid function,conventional POCT method cannot meet the application needs because of the poor accuracy.Therefore,we have developed an active microfluidic chip POCT kit for assessing thyroid function,by using immunofluorescence analysis to detect total triiodothyroxine(TT3),total thyroxine(TT4),free triiodide Thyroxine(FT3),free thyroxine(FT4)and thyroid stimulating hrmone(TSH)in human serum or plasma samples.The results show that the microfluidic chip has the characteristics of low detection limit,high sensitivity,and good accuracy for the five biomarkers of thyroid function.In addition,the chip also has strong anti-interference,good repeatability,and small inter-batch difference.The microfluidic chip has high accuracy in clinical thyroid function assessment.It provides a new POCT detection method for thyroid function diagnosis,laying the foundation for the follow-up clinical application of the POCT kit.