It’s the small things that are usually overlooked and ignored. But small things can have a lot of value. Take the case of the Thirukurral; it is only a collection of poetic couplets, but each couplet has so much value!
Similarly, microscale objects, such as cells, particles, droplets, and microstructures, may be dismissed as they are naked to the human eye, but when these microscopic objects are patterned or arranged in a particular fashion, their uses are endless.
Patterning of microscale objects is the process by which tiny objects (in the range of micrometres), are arranged in a particular fashion, which changes their behaviour and function. This phenomenon is utilised across various fields ranging from biology (creating artificial tissues), electronics (creating sensors, actuators, and micro-optical devices), material sciences (creating crystals and metamaterials), drug discovery (high-throughput screening), energy (patterning electrodes for batteries and fuel cells), and robotics (microrobotics).
However, the usual methods of patterning hinder dynamic control over the formed patterns. Therefore, there is a need to look at other methods for patterning.
Ultrasonic methods fit the bill as a patterning method as it is contactless, label-free, and biocompatible.
But there is another problem in patterning. The device used is very complex in nature, with arrays of piezoelectric sources used as transducers (a transducer is a device that converts one form of energy to another). Therefore, in this study, the authors Mr. Subhas Nandy, Mr. Niladri S. Satpathi, Ms. Monica Manohar, and Dr. Ashis K. Sen, from the Micro Nano Bio Fluidics Unit, Department of Mechanical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India, have manipulated the device used for patterning by making it asymmetric, and with the use of a single piezoelectric source with variable frequencies.
Thus, in this study, the authors have reported tunable patterning of microparticles in an ultrasonically actuated microfluidic cavity (a microfluidic device holds small volumes of fluids in the microscale range. A microfluidic cavity is a cavity within a microfluidic device that holds or processes the fluids at the microscale).
The proposed methodology can be easily extended to incorporate different asymmetrical structures thus paving the way for the creation of more diverse aggregate patterns.
The authors believe that their method greatly simplifies microscale patterning operations and can find potential applications in biomedical engineering and clinical research through controlled cell patterning, tissue engineering, and cell-cell interactions.
Prof. Peer Fischer, Professor of Experimental Physics (Molecular Systems Engineering), and head of the Micro Nano and Molecular Systems Lab at the Max Planck Institute for Medical Research in Heidelberg University, Heidelberg, Germany, gave the crux and importance of the authors’ research with the following comments: “Prof Sen and his group have devised a versatile device that permits ultrasound to be used to assemble and manipulate particles in a microfluidic chamber. A clever design simplifies the setup tremendously, such that only one ultrasound source is needed, while still offering many degrees of freedom for the user. I foresee interesting applications in the field of microparticle and cell manipulation.”
Article by Akshay Anantharaman
Click here for the original link to the paper
