White blood cells are a significant part of immune system, which can prevent human body from infection and invasion of foreign invaders. The count and recognition of white blood cells plays an important role in modern clinical practice. There is an urgent need to modify the conventional methods (such as cytometry), which are time-consuming and labor-intensive for white blood cell counting. This paper describes a microfluidic cytometer for white blood cells integrated a three-dimensional hydrodynamic focusing system and on-chip optical components, which can realize single-cell fluid flow and single-cell detection. Through the experiment, the device achieves the hydrodynamic focusing of cell flow and the detection of side scatter and fluorescence. For classifying and counting of white blood cells, we further perform an experiment using blood samples and get fairly good results.
Acquisition of the genes encoding variable regions of paired heavy and light chains (VH:VL) is crucial, but it is a labor and cost-intensive process in traditional methods. This study presents a novel method in which all processing steps for acquiring natively paired VH:VL genes from single cells are finished in a single microfluidic chip. The microfluidic chip performs single-cell trap/in situ fluorescent examination of antibody specificity/cell lysis/gene amplification all at single-cell level. By a proof-of-concept validation of efficiently acquiring paired VH:VL genes of anti-RBD (which is a key protein of SARS-CoV-2 virus) mAbs from single hybridomas, the microfluidic chip has been proved capable of remarkably improving cell loss/human labor/time cost, and more importantly, determinacy of native VH:VL genes pairing which is one of the most decisive factors of effectiveness for antibody discovery.
The majority of current microfluidic flow cytometers were fabricated by a tractable material, PDMS (Polydimethylsiloxane), which exhibited unsatisfactory optical performances. In this work, we firstly presented an all-glass microfluidic flow cytometer (agFCM) which remarkably improved the optical performance and corresponding blood cell detection accuracy.Picosecond laser was introduced to pattern microfluidic channels, on-chip optical waveguides and on-chip micro-lens on a glass substrate (made with fused silica). The glass debris and burrs caused by laser machining were removed from microfluidic channels by ultrasonic cleaning and CO2 laser reflux respectively. The fabricated glass micro-channel with on-chip lens was sealed by bonding another glass layer to form the agFCM chip. The experimental results demonstrated that, compared with PDMS based devices, agFCM chip improved the optical performances as follows: 1) Scattering haze of material surface was reduced from 50% to 1.4%, effective light transmittance has increased5%.2) the focused excitation spot in detecting area was reduced from 3.60 to 2.64μm. 3) The coupled optical loss of the chip waveguide is reduced to less than 1dB.To sum up, introducing glass as chip material improved the signal to noise ratio by 0.66dB.The performances of agFCM were verified by microsphere experiments. As expected, the improved optical parameters of agFCM resulted in related improvement on detecting accuracy.
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