Flow Through and Lateral Flow diagnostic devices both use membranes as the active media on which the relative biomarkers are printed and the assay is executed. In the Flowthrough device the reagents and sample flow normal to the membrane while in the Lateral Flow device they flow parallel and within the membrane. Both employ an absorbing pad, where in Flow Through it sits under the membrane and for Lateral Flow it sits at the end of the membrane flow path. Hence the assembly and development methods are somewhat different.
In the Flow Through device the conjugate is added in a liquid format after being mixed with the sample and buffers. The original concept for Lateral Flow was to incorporate the conjugate in a dry format on a separate pad along the membrane flow path. More recently this has changed with the use of Lateral Flow devices in that in new test strip designs the conjugate is added in a liquid format mixed with the sample. This is done for several reasons, one being improved performance. The Flow Through device use a dot format for the test and control reagents while a Lateral Flow device uses line formats. The normal flow and spot formats used in the Flow Through device have historically lead to much lower Coefficient of Variable (CVs) that for Lateral Flow and hence the Flow Through technology is considered a quantitative device when used with a reader.
There is growing interest in the Flow Through format as a platform for multiplexed biomarkers using both colorimetric and fluorescent tags due to the ability to achieve quantization and the low cost of producing this type of a format relative to other array formats which require special functional surfaces. The Flow Through format is also more open to multiplexing of biomarkers than Lateral Flow due to the constraints associated to the linear flow limitation associated with the Lateral Flow design. Another trend with the Flow Through is the reduction is size to lower the volume of sample and reagents for development of the test. The Glucose biosensor is probably the most common of biosensors where the typical format is a "sheet" and the reagent is dispensed to a pre-printed electrode pattern. In many biosensor applications, multiple layers of different samples are dispensed in different steps requiring great flexibility as well as high positional accuracy. The sample is allowed to dry down and then is cut, and packaged.
A quantitative testing tool in a biomedical research laboratory setting for multiplex assay, biomarker screening and identification procedures.
Flow Through devices are becoming increasingly popular in biomedical research facilities. They're used for multiplex assay, biomarker screening and identification procedures.
Unlike lateral flow devices, flow through technology does not utilize linear flow. This makes flow through devices more effective in multiplexing biomarkers.
Flow Through devices feature membranes, just like those that are present in their lateral flow counterparts. But the absorbent pads are positioned beneath the membrane in flow through devices.
BioDot's flow through devices feature dot test formats. This, combined with several other features of flow through technology, means this equipment serves as a valuable quantitative testing tool in a biomedical research laboratory setting.