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Recent progress in cytobiology and molecular biology has created an increasing demand for high-resolution analytical approaches that are able to perform rapid identification and quantification of protein analytes in complex mixtures (e.g. cell lysates). Notably, microfluidics offers a central operation platform for the implementation of chemical reactions and biological experiments in a miniaturized manner because of their internal advantages of the extensive sample, reagent economy, high throughput, automated operation, operation fidelity, and strict control over the microenvironment.

As a leading service provider in the field of microfluidic systems, Creative Biolabs has launched an integrated platform for the development of a wide range of rapid and sensitive microfluidic chips to achieve protein digestion, identification, and analysis using electrospray ionization mass spectrometry (ESI-MS) or many other mass spectrometry (MS) detections.

How to integrate Microfluidics with Protein Assay?

A miniaturized membrane reactor is established by manufacturing the microfluidic channels on a poly (dimethylsiloxane) substrate and conjugating the microfluidics to a poly (vinylidene fluoride) porous membrane with adsorptive trypsin. Based on the large surface-area-to-volume ratio of the porous membrane, trypsin onto a poly (vinylidene fluoride) membrane is employed for accomplishing ultrahigh catalytic turnover. The extent of protein digestion in the miniaturized reactor can be directly regulated by the detention time of protein analytes on the trypsin-adsorbed membrane, the temperature of reactions, as well as the protein concentration. The resulting peptide or protein mixtures either are analyzed by ESI-MS or further concentrated and resolved by electrophoresis before the MS analysis.

Fig. 1 An integrated microfluidic platform for protein post-translational analysis (IMPA).^1,3

Case Study

Peptide mass mapping is a powerful technology for protein identification based on proteolytic protein cleavage. The cleavage produces an unusual set of peptide fragments, and their masses may be determined by either matrix-assisted laser desorption/ionization-MS (MALDI-MS) or ESI-MS. The limitations of peptide mass mapping contain massive manual sample preparations and a long time for proteolytic digestion. Therefore, many approaches to miniaturize proteolytic cleavage procedures are exploited and coupled with MALDI-MS. For example, an integrated multichannel microchip interfaced with ESI-MS has been developed and its improved sample throughput capability is shown for a temporal demonstration of melittin digestion. To further promote the speed of trypsin digestion, a microchip enzyme reactor is found by covalently attaching trypsin onto the porous silicon microchannels. The reactor with micro dispensers and shallow nanovials empower fast and automated sample preparation for protein identification through MALDI-MS.

Fig. 2 Ubiquitination assay on chip.^1,3

Advantages of Microfluidic Protein Assay

• Fast operation: microfluidic system enabling rapid identification of proteins in several minutes;
• Low sample volumes: microfluidic system only consuming very little sample (nanogram or less);
• High throughput: operating hundreds of samples at the same time;
• More intelligent: on-line interface with upstream protein separations for the analysis of complex protein mixture.

To be well applied as a clinical diagnostic, a proteomic technology is supposed to be sensitive enough to determine endogenous levels of low abundance proteins, need low sample volumes, cost a short assay time, and ideally be portable to make informed treatment decisions at the point of care. Microfluidic systems are impressed by rapid, integrated, miniaturized characteristics that present an effective platform for protein detections. Under its inherent advantages, the microfluidic system has emerged as a potential operation platform with which to research and develop high-efficiency proteomic technologies.

Services Creative Biolabs Offer

With dedicated devices and extensive expertise in microfluidic techniques, Creative Biolabs offers one-stop microfluidic chip development services to satisfy clients’ special needs on their challenging projects. In particular, our multidisciplinary team and talented engineers make use of the integrated microfluidic chip system to assist clients in varieties of protein assays, including but not limited to:

If you’d like to know more about our personalized microfluidic chip services, please directly contact us or send us an e-mail with specific requests.

Published Data

The findings discussed in the articles related to protein assay on microfluidic chip are presented here:

1. Affinity microfluidics enables high-throughput protein degradation analysis

Fig. 3 Design and strategy toward protein degradation on-chip.^2,3

Many signal transduction events in vivo are regulated by protein degradation. In vitro degradation studies play a crucial role in comprehending cell growth and various cellular functions. Lev Brio et al. proposed protein degradation on a chip (pDOC), which can be used to discover and analyze protein degradation in cell-free extracts.^2,3 The principle of the chip is to fix the expressed target protein in a microchamber through some specified surface chemical methods. Because there are a large number of microchambers on the chip, a large number of fluorescence measurements can be performed in thousands of microchambers using only a small amount of reagents.

References

1. Meirav, Hadas, et al. " Integrated Microfluidics for Protein Modification Discovery." Molecular and Cellular Proteomics. 14.10 (2015): 2824-2832.
2. Brio, Lev, et al. "Affinity microfluidics enables high-throughput protein degradation analysis in cell-free extracts." Communications Biology 5.1 (2022): 1147.
3. Distributed under Open Access license CC BY 4.0, without modification.

For Research Use Only. Not For Clinical Use.