| Description |
A growing need for the separation of nanoparticles may be solved by split flow thin cell fractionation (SPLITT). This work introduces a novel cross-flow based SPLITT microsystem that is capable of high-speed continuous separations based on the size of particles in the sample. Flow-SPLITT is a new member of the SPLITT/FFF family of techniques and uses cross-flow as the driving field and has the potential to be more efficient than diffusion SPLITT or H-filter technology. An asymmetrical cross-flow based SPLITT system has been used to purify 130 nm, 220 nm polystyrene nanoparticles and Bovine Serum Albumin in less than 15 minutes. The work will describe the design, fabrication, and characterization of this new separation technique that is capable of small molecular weight biological separations. A cross-flow is used to induce a "separation field". The cross-flow is drawn out of the channel along its length at a given flowrate. In addition, the inlet flowrates are also arranged such that sample particles are further pushed towards the frit-membrane wall. Most of the sample particles will elute from the outlet a and only the smaller particles in a given size range (larger than the pores of membrane wall) will diffuse and cross the inlet splitting plane and be collected at the outlet b. The cross-flow SPLITT microsystem consists of two fluidic channels that are separated by a splitter layer made of a stiff Mylar sheet. One side of the flow unit utilizes a porous frit that allows for cross-flow in or out of the channel as one wall and glass slide as another wall and push-pull syringe pumps have been used for flowing the buffer solution and a t-injector and microliter syringe are to inject the sample for preliminary characterization of the system. Standard fittings are used to connect the microsystem and the syringe pumps. Future work will involve optimizing the flowrate combinations for improved and continuous separation of more complex samples. |
