Fabrication Of Imaging Chambers For Counting 3-Part Differentials Of White Blood Cells With Portable Capability Based On Large Field-of-View Imaging

Blood count is one of the most common tests in hospitals which can be used to screen and assess diseases.The use of blood cell counts for point of care detection enables fast and convenient diagnostics.Therefore,it is of great significance to develop methods of portable blood cell counting.Previously,the concept of counting blood cells in diluted blood samples using large field-of-view microscopic imaging has been developed.However,this method has to use imaging chambers from commercial providers.When imaging white blood cells,their total number in the imaging chamber is statistically small,causing possible inaccuracy of differentiating sub-populations of white blood cells(WBCs).Meanwhile,the commercial imaging chambers used for sample preparation are costly and not environmentally friendly.Aimed at portable blood cell counting,this thesis introduces the strategy of directly preparing undiluted blood samples and the fabrication methods of two types of imaging chambers for counting 3-part differentials of WBCs.The thesis mainly includes 3 parts as shown in the following:1)Microcontact printing method is used to fabricate imaging chambers.An elastic stamp is used to transfer silicone sealant and seal the slide and coverslip together,in order to control the thickness of the imaging chamber.The thickness of the imaging chamber is approximately 20μm.By controlling it,undiluted whole blood forms a monolayer of WBCs.The total number of WBCs is large enough,allowing statistical accuracy of differentiating their 3 major sub-populations.After imaging experiments and data processing,accurate WBC counts with 3-part differentials were obtained,verifying that the imaging chambers made by microcontact printing is capable to differentiate different types of WBCs.2)Hydrophilic channel method is used to fabricate imaging chambers.A hydrophilic channel is formed by soaking the slide in a solution of hydrophilic silicon dioxide nanoparticles,and hydrophobic edges are produced by microcontact printing of a silane onto the slide.A blood sample diluted by a factor of 5× flows into the imaging chamber automatically,driven by the hydrophilic force.The sample contains glycerin in order to maintain humidity and the cellular morphology.WBCs form a monolayer within the chamber,and the number of WBCs is statistically enough allowing accurate counting of WBC sub-populations.The fabrication procedure is simple,and is expected to be standardized in the future.After imaging experiments and data processing,accurate WBC counts with 3-part differentials were obtained,verifying that the imaging chambers made by the hydrophilic channel method is capable to differentiate different types of WBCs.3)The two types of imaging chambers were used to count WBCs with 3-part differentials for clinical blood samples.There is a good agreement between our results and the clinical values.The reproducibility of our results is good.In summary,the fabrication methods of the two types of imaging chambers,combined with large field-of-view cellular imaging and automatic data processing,provide a solution for counting 3-part differentials of WBCs towards the goal of point-of-care blood counting tests.