Liquids on-chip: direct storage and release employing micro-perforated vapor barrier films

Czurratis, Daniel; Beyl, Yvonne; Grimm, Alexander; Brettschneider, Thomas; Zinober, Sven; Lärmer, Franz; Zengerle, Roland

doi:10.1039/c5lc00510h

Cited by 13 publications

(13 citation statements)

References 27 publications

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“…6 To realize on-chip sample preparation, reagents are integrated in microfluidic devices and released upon contact with the inflowing sample. Compared with liquid reagents [7][8][9][10] , integrating dry reagents in microfluidic devices is beneficial for long-term storage and convenient for transportation, due to the better stability of reagents in the dry state. 11 However, the controlled dissolution of the reagent and on-chip mixing with the added sample is challenging.…”

Section: Introductionmentioning

confidence: 99%

Controlled antibody release from gelatin for on-chip sample preparation

Zhang¹,

Wasserberg²,

Breukers³

et al. 2016

Analyst

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A practical way to realize on-chip sample preparation for point-of-care diagnostics is to store the required reagents on a microfluidic device and release them in a controlled manner upon contact with the sample. For the development of such diagnostic devices, a fundamental understanding of the release kinetics of reagents from suitable materials in microfluidic chips is therefore essential. Here, we study the release kinetics of fluorophore-conjugated antibodies from (sub-) µm thick gelatin layers and several ways to control the release time. The observed antibody release is well-described by a diffusion model. Release times ranging from ~20 s to ~650 s were determined for layers with thicknesses (in the dry state) between 0.25 µm and 1.5 µm, corresponding to a diffusivity of 0.65 µm 2 /s (in the swollen state) for our standard layer preparation conditions. By modifying the preparation conditions, we can influence the properties of gelatin to realize faster or slower release. Faster drying at increased temperatures leads to shorter release times, whereas slower drying at increased humidity yields slower release. As expected in a diffusive process, the release time increases with the size of the antibody. Moreover, the ionic strength of the release medium has a significant impact on the release kinetics. Applying these findings to cell counting chambers with on-chip sample preparation, we can tune the release to control the antibody distribution after inflow of blood in order to achieve homogeneous cell staining. IntroductionOne of the major fields of applications for microfluidics is in vitro diagnostics, with great potential particularly in point-of-care diagnostics. 1-3 Many process steps and sensing principles have been realized on microfluidic devices. 4 Recently, on-chip sample preparation using reagents stored in microfluidic devices has received more and more attention. 5 On-chip sample preparation can eliminate the dependence on external instrumentation for reagent delivery as well as benchtop sample treatment, thus integrating the complete test into one disposable. 6 To realize on-chip sample preparation, reagents are integrated in microfluidic devices and released upon contact with the inflowing sample. Compared with liquid reagents 7-10 , integrating dry reagents in microfluidic devices is beneficial for long-term storage and convenient for transportation, due to the better stability of reagents in the dry state. 11 However, the controlled dissolution of the reagent and on-chip mixing with the added sample is challenging. Especially in applications where the inflowing sample passes a reservoir of the reagent and slowly dissolves or washes out the stored reagent 12-15 , very precise control of the sample flow and the reagent release process is required. In contrast, mixing between sample and reagents in stopped flow applications can be realized simply by releasing the reagent with sufficient delay after the sample inflow has stopped at the required position on the chip. 16 To realize controlled reagen...

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Section: Introductionmentioning

confidence: 99%

Controlled antibody release from gelatin for on-chip sample preparation

Zhang¹,

Wasserberg²,

Breukers³

et al. 2016

Analyst

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“…Reservoirs are good choices for liquid storage in microfluidic devices. With a flexible thermoplastic elastomer membrane as a seal, liquid reagents can be stored directly in the microchip [21] ( Figure 2D). Once it is needed, a pressure is applied to deflect the membrane and the stored reagents are released for further processing.…”

Section: Liquid Reagents Storagementioning

confidence: 99%

“…Reproduced with permission. [21] Copyright 2015, Royal Society of Chemistry. E) The photograph and scheme of the microfluidic device that utilizes a porous PDMS sponge for liquid storage and release.…”

Section: Nanocarriers For Reagents Storagementioning

confidence: 99%

Advances in Reagents Storage and Release in Self‐Contained Point‐of‐Care Devices

Deng

Jiang

2019

Adv Materials Technologies

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Microfluidics has emerged as a useful material for point‐of‐care testing. However, conventional microfluidic devices rely on multiple steps to complete the detection process, which may not be acceptable for untrained users. The emerging “self‐contained” point‐of‐care devices, with all necessary reagents prestored in, address this limitation. This paper summarizes the recent advances of self‐contained point‐of‐care devices, with emphasis on the approaches for reagents integration and manipulation. Due to the intrinsic similarity and relevance of these approaches in pharmaceutical applications, several examples about drug delivery in vivo are presented. Different approaches are compared and future trends for the development of self‐contained point‐of‐care devices are outlined.

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“…Batch scale encapsulation and storage of liquid or dried sample in silicon [17,25], metallic [26], glass [4], and polymer hybrid [1][2][3]16] reservoirs enables long-term storage and often hermetic sealing, but is not compatible with polymer microfluidic integration. Sealing of polymer wells by thermal bonding [5,8] is not suitable for temperature sensitive liquids, and sealing of wells by epoxy gluing [10,16] complicates downscaling of aqueous liquid storage in multiplewell arrays. Wafer-level entrapment using stiction in parylene C microreservoirs enables down to picoliter volume storage [6], but suffers from significant liquid loss during storage.…”

Section: Liquid Releasementioning

confidence: 99%

“…Integrated storage and release of reagents in microfluidic platforms [1][2][3][4] enable hands-off operation and reduces the need for external interfacing. Despite previous progress [5][6][7][8][9][10], integrated encapsulation, storage and release of nanoliter to microliter volumes of aqueous solutions in polymer microfluidic devices face unresolved technical challenges. Specifically, tiny volumes of liquid are prone to evaporation during encapsulation and biological contents are prone to denaturation.…”

Section: Introductionmentioning

confidence: 99%