Welcome to the Embryo Sorter Web Site!

The information presented here describes how we built a device that can sort Drosophila embryos based on their levels of fluorescence.  A number of applications for this machine as well as a validation of its performance are described in the accompanying paper.
 

Overview

The machine functions by determining the levels of fluorescence of embryos that are suspended in a buffer.  Solution is continuously pumped through the machine.  Embryos randomly enter this fluid stream and pass through an optical cuvette (see below) where they are excited by an argon laser.  The emitted light from the embryos is detected by two Photomultiplier Tubes (PMT’s).  The PMT’s send a signal to a microcontroller which signals to the computer to draw a peak for both the GFP and the autofluorescence.  A microcontroller determines whether the peaks are above or below a defined threshold and sends a signal to an electromagnetic switch to divert the fluid flow to either a waste or save position. 

Overview Diagram

The purpose of this supplemental web site is to provide information on how we built the machine in order to help other people who wish to build an embryo sorter.  This project was initiated about 2.5 years ago and after 2 years we had a working prototype that could accurately sort Drosophila embryos.  We then made several modifications and improvements to this prototype which resulted in the second generation embryo sorter that is described here.  Because the construction was an ongoing process incorporating many different adjustments we do not have blueprint plans for the machine.  What this site provides is a parts list for the commercially available items and also both schematic drawings and photographs of the custom made parts.  Navigation to different links on this site can be made by selecting from the bars on the top left hand side of the page.

There are a number of improvements that could be made in the next generation machine.  For example making a lighter weight switch will increase the speed of sorting.  Currently all of the embryo timing and sorting decisions are being made through hardware and we are sorting based upon the peak values for GFP.  Doing these calculations through software would allow sorting to be done based on the integrated area under the curve.  This may become necessary when sorting embryos that express GFP only in a small number of cells.  We would appreciate if you could let us know of any modifications or improvements that you have made to the design of the instrument while making your own. 

In order to build this device extensive experience is required in electronics (including microcontrollers), basic programming, optics, and machining. 
 
 

 This technology is covered by Stanford patent 6,482,652