Using hydrogel beads to achieve high encapsulation rate (beating poisson encapsulation statistics)
By special designed microfluidic channels and same schematics of microfluidic chip as drop-seq chip, we used hydrogel bead to demonstrate 90% hydrogel encapsulation rate (as shown in the Figure below) on our single cell analysis R&D platform.
Figure. Schematics of microfluidic chip for flexible hydrogel beans and cells isolation capture
Demonstration video of cell and hydrogel bean encapsulation by droplets with a custom design PDMS microfluidic chip. The video is captured at 1000 FPS using PreciGenome Single Cell Analysis System.
The figure shows that 90% of droplets contain single hydrogel bead. By attaching functional groups, hydrogel beads have diverse applications, such as cell culture, drug delivery study, etc. Combining mono-dispersed hydrogel beads with different attachments and microfluidic droplet technology, high encapsulation rate of single cell and single bead is achieved, by which many independent reaction compartments are formed. Researchers can study individual cell behaviors with different environment. By adding barcodes on hydrogel beads, single cell RNA seq can be achieved. Researchers are able to study rare cancer cell mutation, response to new drugs, and CRISPR screening, etc. Using this platform, cell isolation and sorting can be achieved as well.
Droplet-based DNA/RNA Seq Applications of Single Cell Analysis R&D System
PreciGenome provides an automated, microfluidic droplet-based platform for single cell research that encapsulates cells and barcoded beads.
The system is flexible enough that allows researchers to perform drop-seq like experiments (using macosko sequencer on polystyrene beads as barcodes, Poisson encapsulation statistics) or in-drop like experiments (using hydrogel beads as barcodes carrier; the encapsulation rate for hydrogel beads can go up to 90%; encapsulation rate for one cell and one bead in a single droplet can reach as high as 9%).
Using polystyrene beads to achieve Poisson encapsulation statistics
We used two types (different optical property) of 10um polystyrene beads to mimic drop-seq cell and barcoded bead capturing process. As shown in the Figure below, bead 1 and bead 2 are loaded in two wells to mimic barcoded polystyrene beads and cells, respectively. In the third well, oil is loaded to help generate droplets. Using our platform, stable droplets with uniform size can be generated. Bead 1 and bead 2 are encapsulated in droplets following Poisson statistics. In order to minimize two same beads encapsulated in one droplet, beads need to be diluted such that about 10% of droplets contain one type of beads. Therefore 1% of droplets contain single bead 1 and bead 2 as shown in Figure below.