A microfluidic approach to rapid sperm recovery from heterogeneous cell suspensions

The isolation of sperm cells from background cell populations and debris is an essential step in all assisted reproductive technologies. Conventional techniques for sperm recovery from testicular sperm extractions stagnate at the sample processing stage, where it can take several hours to identify viable sperm from a background of collateral cells such as white bloods cells (WBCs), red blood cells (RBCs), epithelial cells (ECs) and in some cases cancer cells. Manual identification of sperm from contaminating cells and debris is a tedious and time-consuming operation that can be suitably addressed through inertial microfluidics. Microfluidics has proven an effective technology for high-quality sperm selection based on motility. However, motility-based selection methods cannot cater for viable, non-motile sperm often present in testicular or epididymal sperm extractions and aspirations. This study demonstrates the use of a 3D printed inertial microfluidic device for the separation of sperm cells from a mixed suspension of WBCs, RBCs, ECs, and leukemic cancer cells. This technology presents a 36-fold time improvement for the recovery of sperm cells (> 96%) by separating sperm, RBCS, WBCs, ECs and cancer cells into tight bands in less than 5 min. Furthermore, microfluidic processing of sperm has no impact on sperm parameters; vitality, motility, morphology, or DNA fragmentation of sperm. Applying inertial microfluidics for non-motile sperm recovery can greatly improve the current processing procedure of testicular sperm extractions, simplifying the fertility outcomes for severe forms of male infertility that warrant the surgery

Identification of Mouse Serum miRNA Endogenous References by Global Gene Expression Profiles

MicroRNAs (miRNAs) are recently discovered small non-coding RNAs and can serve as serum biomarkers for disease diagnosis and prognoses. Lack of reliable serum miRNA endogenous references for normalization in miRNA gene expression makes single miRNA assays inaccurate. Using TaqMan® real-time PCR miRNA arrays with a global gene expression normalization strategy, we have analyzed serum miRNA expression profiles of 20 female mice of NOD/ShiLtJ (n = 8), NOR/LtJ (n = 6), and C57BL/6J (n = 6) at different ages and disease conditions. We identified five miRNAs, miR-146a, miR-16, miR-195, miR-30e and miR-744, to be stably expressed in all strains, which could serve as mouse serum miRNA endogenous references for single assay experiments

3D printing enables the rapid prototyping of modular microfluidic devices for particle conjugation

© 2020 Elsevier Ltd Antibody micro/nano-particle conjugates have proven to be essential tools in many diagnostic and nanomedicine applications. However, their production with homogenous coating and in a continuous fashion remains a tedious, labor-intensive, and costly process. In this regard, 3D micromixer-based microfluidic devices offer significant advantages over existing methods, where manipulating the flow in three dimensions increases fluid contact area and surface disruption, facilitating efficient mixing. While conventional softlithography is capable of fabricating simple 2D micromixers, complications arise when processing 3D structures. In this paper, we report the direct fabrication of a 3D complex microchannel design using additive manufacturing for the continuous conjugation of antibodies onto particle surfaces. This method benefits from a reduction in cost and time (from days to hours), simplified fabrication process, and limited post-processing. The flexibility of direct 3D printing allows quick and easy tailoring of design features to facilitate the production of micro and nanoparticles conjugated with functional antibodies in a continuous mixing process. We demonstrate that the produced antibody-functionalized particles retain their functionality by a firm and specific interaction with antigen presenting cells. By connecting 3D printed micromixers across the conjugation process, we illustrate the role of 3D printed microchannels as modularized components. The 3D printing method we report enables a broad spectrum of researchers to produce complex microfluidic geometries within a short time frame