Robust lumped-element modelling of centrifugo-pneumatic and siphon valving towards highly predictive simulation of large-scale integrated microfluidic networks

Drastic parameter reduction by lumped-element modelling by descriptors for flow control elements such as hydrodynamic resistance (“resistor”) pressure head (“voltage”) and flexible parts (“capacitance”) is the method of choice for simulating complex centrifugal microfluidic networks. As all liquid on such “Lab-on-a-Disc” (LoaD) systems are subject rotationally induced field, valving techniques are absolutely essential to orchestrate the serial release and processing of on-board samples and reagent

Liposome immunoassay based on bio luminescent detection and its application to on-chip analysis

Luc-encapsulated liposomes were employed to develop on-chip immunoassays. Straight-channel chips were better than microbead for V-cup chips to immobilize several antibodies. Straight-channel chip that has PDMS flat substrate and wider channel (1000 μm) was optimum for this assay. To detect high BL intensity, fast flow rate (300 μl/min) was better than slower flow rate because channel was filled up with substrate quickly. However, substrate volume and lysis buffer didn't affect the detecttion high BL intensity. This implies that a sufficient amount of substrate was delivered to Luc in the liposomes. The LOD of CRP in this assay was 10 ng/mL

Lipophilic-membrane based routing for centrifugal automation of heterogeneous immunoassays

We demonstrate centrifugal [liquid handling] automation of an Enzyme-Linked Immuno-Sorbent Assay (ELISA) for the detection of anti-p53 antibodies in whole blood. On this “Lab-on-a-Disc” (LoaD) platform, all unit operations were implemented by event-triggered rotational flow control. In order to avoid interference during absorbance measurement from the solid phase in this heterogeneous assay format, it is pivotal that the intermediate reaction product is eventually forwarded from the incubation chamber to a distinct optical measurement chamber. To this end we have devised routing of flows by lipophilic film valves (LFVs) which remain intact in aqueous and selectively dissolve when exposed to an ancillary, oleophilic solvent