Details in Microfluidics Operation

#1. Why there is no continuous flow.

Bubbles are inevitable, because somehow the air from the syringe will come in.
in normal case, at last, the pusher of the syringe reached the limit, then we can draw the pusher back a little bit, and then push again to thrust the solvent forward.

in that sense, the air block will be injected.

but you never see the flow can be separated into many segments.

#2.Setup.

At first, Adjust the pressure to 500 ml/h to let the flow quickly through the first tube.
then when the flow almost touch the chip, adjust it to 50 ml/h (actually I am not sure the unit), or the leakage will happen.
the cell/antibody/GMBS/Avidin perhaps flow with different rates. But roughly 1 h to finish.

you also can setup the volume to be injected to avoid injected air.

#3. Fabrication:

approach (soft photolithography):

Mold Fabrication

CAD-pattern for photomask fabrication. 将光刻掩膜利用光刻技术将pattern转移到涂有光刻胶的硅片上

based on the pattern, fabricate a mould. expose SU-8 negative photoresisit through the photomask. UV exposed photoresist will polymised and the rest will disolve and be washed away in the developing stage.
SU-8 mould as a template(剩余SU-8形成凸起会形成阳模去进行PDMS微流控芯片的制作) for PDMS pre-mix casting

These three steps can be achieved by 3D printer

PDMS Chip Fabrication:

将模板硅片用含惰性基团(如氟代烷基)的硅烷处理以防止下一步操作时PDMS和硅片的永久键合. 憎水，羟基-hydrophobic
将PDMS 预塑体(由两种不同化学官能化的硅氧烷组成, 按照一定比例混合)浇铸到模板硅片上, Degas!!抽气泡，耐心。
之后将其处于40℃~80℃加速PDMS预塑体固化,curing in the oven, solid PDMS with the replicated microstructure wiil be peeled off
再将固化后的PDMS从模板上揭下来, 用打孔针在合适的位置上打孔作为溶液的进出口, hole punching inlets.outlets

先打孔，再接合！
最后将PDMS 基片带有管道的一面与其他平面结合(silicon wafer/glass), 进行可逆或不可逆性的密封完成芯片制作.bond with glass substrate

##4. Functionalisation-Capture Efficiency

Workflow

oxygen plasma hydrophobic
and bond PDMS with Chip

Chemcial func

Biofunc

antibody

cells.

-control the surface CHEMISTRY!
-specifity of the antibody! (bioconjugation)
FabricationPDMS
pouring