Lee, Kangsun Kim, Choong Ahn, Byungwook Panchapakesan, Rajagopal Full, Anthony R. Nordee, Ledum Kang, Ji Yoon Oh, Kwang W. 2024-01-20T21:34:50Z 2024-01-20T21:34:50Z 2021-09-03 2009-04 1473-0197 https://pubs.kist.re.kr/handle/201004/132632 In this paper, we propose a generalized serial dilution module for universal microfluidic concentration gradient generators including N cascaded-mixing stages in a stepwise manner. Desired concentrations were generated by means of controlled volumetric mixing ratios of two merging solutions in each stage. The flow rates were adjusted by controlling channel length, which is proportional to fluidic resistance in each channel. A generalized mathematical model for generating any complex concentration and output flow rate gradients is presented based on the fact that there is an analogy between microfluidic circuits and electrical circuits. The pressure drop corresponds to a voltage drop, the flow rate to an electrical current, and the flow resistance to an electrical resistance. A simple equivalent electrical circuit model was generalized, and in the model each channel segment was represented by an electrical resistance. As a result of the mathematical modelling, the only variable parameter in the generalized serial dilution module was the channel length. By the use of the generalized serial dilution module with N 4, three types of microfluidic gradient generators for linear, logarithmic and Gaussian gradients were successfully designed and tested. The proposed strategy is capable of generating universal monotonic gradients with a single module or arbitrary gradients with multiple modules ranging from linear to complex non-linear shapes of concentration gradients as well as arbitrary output flow rate gradients in a stepwise manner. The simple universal gradient generation technology using the generalized serial dilution module will find widespread use in the greater chemical and biological community, and address many challenges of gradient-dependent phenomena. English Royal Society of Chemistry CELL-CULTURE CHEMOTAXIS DEVICE MIGRATION PARALLEL NETWORK ARRAYS Generalized serial dilution module for monotonic and arbitrary microfluidic gradient generators Article 10.1039/b813582g 1 Lab on a Chip, v.9, no.5, pp.709 - 717 Lab on a Chip 9 5 709 717 scie scopus 000263466600012 2-s2.0-60649120060 Biochemical Research Methods Chemistry, Multidisciplinary Chemistry, Analytical Nanoscience & Nanotechnology Instruments & Instrumentation Biochemistry & Molecular Biology Chemistry Science & Technology - Other Topics Instruments & Instrumentation Article CELL-CULTURE CHEMOTAXIS DEVICE MIGRATION PARALLEL NETWORK ARRAYS