Microfluidic concentration-on-demand combinatorial dilutions

Abstract

We present a microfluidic network-based combinatorial dilution device to generate on-demand combinatorial dilutions of all input samples in the range of a 3D simplex-centroid. The device consists of an initial concentration control module and a combinatorial dilution module. In the initial concentration control module, the concept of using a single common channel has been incorporated to generate desirable concentrations of each sample, diluted independently in response to variable input flow. Then, the diluted samples flow into the combinatorial dilution module to generate a full set of seven combinations from the three samples. First, we investigated the performance of the initial concentration controller by computational simulation (CFD-ACE ? ). The simulated output concentrations are extremely close to the expected theoretical values. Further, a PDMS-based initial concentration controller was fabricated, and its linearity and independency were tested with fluorescent dye. Then, we designed, simulated, and tested a combinatorial dilution device integrated with the initial concentration controller. Finally, as proof-of-concept, we performed a simple combinatorial cytotoxicity test with three drugs (Mitomycin C, Doxorubicin, and 5-FU) for MCF-7 cancer cells.

An integrated microfluidic device for two-dimensional combinatorial dilution

“…4 and S10†). 20 The set of well compositions define the device output behaviour, from which all other outputs may be calculated. For example, if the three device inputs contained the concentrations c 1 , c 2 , and c 3 of a certain solution A, the resulting concentration of A in well n after injection m would be the weighted average $$c_{\text{italicnm}}=w_{\mathit{\text{nm}}1}{c}_1+w_{\mathit{\text{nm}}2}{c}_2+w_{\mathit{\text{nm}}3}{c}_3$$ …”

“…20,24 Few microfluidic combinatorial devices incorporate gradients, which require more complex channel networks. 20,23 A more powerful combinatorial device employs a valve-based mixer/multiplexer to combine up to 32 aqueous solutions in 1024 desired combinations. 26 The trade-off with such a device is the extended time required to prepare the mixed solutions.…”

Pressure-Driven Microfluidic Perfusion Culture Device for Integrated Dose-Response Assays

“…To address these issues, serial dilution microfluidic networks for generating various concentration profiles have been developed. 34,[68][69][70][71][72] We previously described a serial dilution microfluidic network for generating arbitrary monotonic concentration profiles (Fig. 3).…”

Arrayed cellular environments for stem cells and regenerative medicine

“…Microfluidic platforms permit the generation of a large spectrum of conditions based on a limited number of input compounds, as demonstrated by devices generating gradients [5, 6], dilution series [33–35], and combinatorial/full‐factorial arrays [36–38]. Nanoliter‐scale cell culture arrays of 64–100 chambers have been used to culture HeLa cells under continuous medium perfusion [39], and were coupled with a diffusive‐mixing gradient generator providing discrete concentrations to columns of the array [40] to demonstrate growth differences under eight concentrations of serum (Fig.…”

“…Other combinatorial mixing systems of three to four components have been demonstrated (Fig. 3E), extending the accessible parameter space [35, 36, 46]. Such systems are potentially useful for cytotoxicity testing in stem cell‐derived model systems, or extensible to investigating stem cell behavior under a range of supportive or pro‐differentiation environments.…”