Sample Introduction and Sample Pretreatment in Microfluidic Chip

Inquiry

Microfluidics is a vibrant and expanding field with the potential for solving many challenges in single-cell analyses, molecular diagnostics, and in vitro tissue models, etc. With the advantages of miniaturization, integration, and automation, microfluidic systems have attracted more and more attention and have experienced rapid growth in the past two decades. However, the sample introduction and pretreatment into microfluidic devices represents one of the remaining hurdles towards achieving true miniaturized total analysis systems. It is urgent to develop and optimize the sample manipulation techniques to advance the practical applications of microfluidic technology.

Importance of Sample Introduction and Sample Pretreatment

Various microfluidic platforms have been applied in molecular diagnostics and biomarker analysis, showing promise to provide rapid, inexpensive, efficient, and portable diagnostic solutions. Typically, sample specimens are limited in volume, contain matrix-related interferences, require multiplex analysis and have low target analyte concentrations. Before the real samples reaching the analytical step, it nearly requires significant pre-treated steps, including sample introduction, injection, mixing, reaction, dispensing, separation, and detection, which is a fully integrated microsystem. Therefore, sample manipulation is a key part of the analysis in the microfluidic device.

Fig.1 A Generic Microfluidic Chip with the sample preparation, selection and detection of bio/nano/micro-particles. (Islam, 2012)

Sample Manipulation in Microfluidic Chip

Microfluidic sample manipulation has been widely used in sample preparation and molecular analysis systems (nucleic acids, proteins, pathogens, and small molecules) on-chip. The common sample preparation processes include analyte purification, enrichment and labeling.

Molecular affinity extraction

Microfluidic sample preparation significantly simplifies the downstream analysis by extracting trace amounts of desired analytes from a complex sample matrix. It selectively extracts, preconcentrates and labels selected analytes in an automated fashion. The commonly used methods are based on the affinity of antigen-antibody or aptamers-target molecule. They have been used for the selective capture of desired molecules in microfluidics.

Sample preconcentration

A preconcentration step can be desirable to improve detection, since analytes are often present in trace amounts. Electrokinetic methods, filtration or chromatographic interactions are usually used on a microfluidic platform.

Table.1 On-chip sample preconcentration. (Sonker, 2017)

Sample Introduction and Sample Pretreatment in Microfluidic Chip

Sample labeling

Analyte labeling is an important sample pretreatment step besides preconcentration and purification, which can be performed on a chip to save time. Microfluidic labeling requires loading, reacting and purifying, and typically uses support inside the microchannels. Fluorescent labeling is the most common method being explored. Scientists have developed an integrated microfluidic device on a glass substrate for electrokinetic labeling and separation of peptides and proteins, which allowed the analysis of proteins and peptides in 5 min, offering process integration and speed.

Microfluidics can be used to miniaturize and integrate sample manipulation processes on a microchip platform. It offers significant advantages like low cost, rapid analysis, and small sample requirements. As a pioneer and the undisputed global leader in the field of microfluidic development, Creative Biolabs offers a suite of custom microfluidics development services to benefit the sample manipulation processes during on-chip DNA analysis, protein detection, immunoassays, etc. If you are interested in our services, please do not hesitate to contact us for more detailed information.

References

Islam, N.; Sayed, S. MEMS microfluidics for Lab-on-a-Chip Applications. INTECH Open Access Publisher. 2012.
Sonker, M.; et al. Recent advances in microfluidic sample preparation and separation techniques for molecular biomarker analysis: A critical review. Analytica chimica acta. 2017, 986: 1-11.

For Research Use Only. Not For Clinical Use.