Author: Erica Francis

“Application of Inertial Microfluidics for Isolation and Removal of Round Spermatids from a Spermatogenic Cell Sample to Assist In-Vitro Human Spermatogenesis” authored by Sabin Nepal, Joey Casalini, Alex Jafek, and Bruce Gale was recently published in Micromachines.

The article outlines the used of inertial microfluidics for isolating round spermatids from other germ cells and purifying spermatogenic cells as a way of improving in-vitro spermatogenesis to address male infertility. A custom PDMS microfluidic spiral channel for performing separation is designed, fabricated, and tested. The custom device does not experience clogging issues, a problem encountered in a commercially available spiral device. Additionally, the fabricated device achieves 86% purity in a single pass, an improvement over the 38% seen with STA-PUT – a method based on velocity sedimentation commonly used in this application. Validation results of the fabricated device are shown in the figure with the full article being found at https://doi.org/10.3390/mi16050500.

Authored by Yunhao Peng, Bruce K. Gale, and Himanshu J. Sant, “Waterborne protozoan parasite detection using two-frequency impedance flow cytometry” was recently published in Analytical Methods.

A common cause of gastrointestinal diseases, waterborne parasitic protozoa are micron-sized parasites present in water sources. Therefore, the article outlines the development of a microfluidic water monitoring system based on impedance flow cytometry for the detection of these parasites. By utilizing parallel rather than coplanar electrodes, a limit detection of <0.1% volume ratio is achieved. Additionally, to improve sample discrimination, both a low and high frequency are applied simultaneously, making the method outlined in the article distinct from other proposed systems. A schematic of the monitoring system is displayed in the figure and the full journal article can be found at https://doi.org/10.1039/D5AY00184F.

“A spiral channel with integrated microelectrodes for label-free particle lateral position and size characterization,” authored by Yunhao Peng, Bruce K. Gale, and Himanshu J. Sant, was recently published in Biomedical Microdevices.

In the article, a spiral-shaped microfluidic channel integrated with modified-trident shaped microelectrodes is utilized to analyze and quantify separation of different sized particles. Lateral particle position corresponds to the ratio of peak amplitudes, while peak amplitude indicates particle size and vertical position. The device yields a particle size estimate sensitivity of 2.15 µm/mV. The device fabrication process is displayed in the figure and the full journal article can be found at https://doi.org/10.1007/s10544-025-00742-5.

Yunhao Peng et al. recently published an article entitled “Modified trident-shaped electrode design for particle lateral position detection in microfluidic impedance flow cytometry” in Sensors and Actuators: A. Physical.

The article outlines the use of modified trident electrodes inside a microfluidic channel for the implementation of impedance flow cytometry for the detection of single particles and their lateral positions. The proposed design is displayed in the Figure below. The device is shown to detect impedance differences caused by less than 0.02% volume displacement. Additionally, using amplitude values, two different-sized microspheres were identified while showing an increase in signal amplitude with a smaller distance between electrodes. The full article can be found here: https://doi.org/10.1016/j.sna.2024.116062.

 

Figure. Illustration of the proposed trident-shaped electrode for the detection and measurement of lateral particle locations (y) of flowing particle/cells inside a microfluidic channel.