Static droplet array (SDA) is a necessary and indispensable tool for high-capacity screening testing or determination of specific cells or analytes (whose chemical components are substances that identify targets) for identification and targeting. However, extracting and collecting target droplets containing unique analytes or cells from SDA remains the main technical bottleneck limiting its wider application.
Researchers from the Single Cell Center of the Chinese Academy of Sciences Qingdao Institute of Bioenergy and Process (QIBEBT) and their collaborators have developed a new system, Optical On Demand Droplet Release (OODR), by integrating laser technology and indium tin oxide (ITO) layer into a droplet microfluidic chip. The OODR system allows for the use of more user-friendly methods in screening assays while reducing the amount of samples and reagents required without affecting efficiency, cell viability, or analytical accuracy.
The success of the OODR system not only makes the technology more efficient and cost-effective, but also expands and improves SDA tools by improving single cell analysis.
Our ultimate goal is to establish an automated and efficient OODR system to expand the application of SDA in various fields, "said Dr. Wang Xixian, co lead author of the study.
We have successfully used EasySort Compact for single cell automatic sorting, "said Professor Ma Bo, the corresponding author and single cell center. This newly developed OODR system has improved the sorting ability from a single cell level to a single droplet level. It can not only target single cells, but also sort droplets containing one cell, multiple cells, or even only reagents.
Another corresponding author and director of the Single Cell Center, Professor Xu Jian, stated that they are currently utilizing artificial intelligence and machine learning to create an automated system using EasySort instruments to minimize human involvement. Ideally, automation can also make it easier for non professionals to use, further expanding the application range of OODR technology.
According to the chip design used by the researchers, the size of the microbubbles has been proven to be crucial for the successful release of droplets. By grinding micro bubbles of the correct size (40 μ m) And keeping the laser intensity within the correct range to generate the heat required to form bubbles, without reducing the integrity of the cells, achieved the expected results, and the droplets only took three seconds under appropriate conditions.
By using white or fluorescent imaging to identify droplets, they can be easily "packaged" and output in a drop by tube (ODOT) manner through capillary force, allowing the liquid to move without any external force and enter the pores or tubes in a high flux manner for further analysis. The provided images help to classify the morphology of the target bacteria, which is difficult to achieve without existing static images.
OODR not only facilitates the packaging and release of target droplets in SDA, but also does not seem to affect the cell culture ability, which is crucial when further live cell analysis is needed. In addition, the reduction in the amount of reagents required and the reduction in the sample size required for analysis mean a more cost-effective approach than other available methods.
Their research results were published in the August 25th issue of the journal Biosensors and Bioelectronics.
The working principle of OODR is to precisely heat the ITO layer with a laser to generate microbubbles, which can selectively push target droplets out of the chamber on the microfluidic chip based on a droplet single cell sorting system (such as EasySort Compact), "said Dr. Diao Zhidian, the first author of the study. The successful use of Escherichia coli and yeast cells indicates that the OODR system has broad applicability to other cells.
Optical On Demand Droplet Release (OODR) system based on EasySort Compact.
Source: Laser Network
