Title:
Συσκευή Παρακολούθησης Καλλιέργειας Κυττάρων
Date: November-2014

Team Κ06-2014: Παντερής Μιχάλης, Τρανακίδης Παύλος, Χριστοδούλου Δημήτρης
Students, Dept of Mechanical Engineering NTUA

Short Abstract

The aim of this project was the design of a device which houses a microscope camera in order to monitor the growth of cell cultures cultivated inside an incubator under given conditions of temperature and humidity. In addition a software was developed for the measurement of cell-growth in a desirable period of time (confluency).

Acknowledgements

We would like to thank Marina Ioannou and the rest of the biolab-staff for their help and cooperation during the various experiments, Dimitris Tzeranis for his valuable advice and Alex Polesiuk and George Kanakaris for their help in the manufacture procedure.

Introduction

The measurement of confluency in a cell culture until quite recently demanded the direct interference of the biologist to the experiment. Besides being harmful for the experiment, it is also time consuming. This led to the development of various devices which measured confluency, and other factors of the cell culture, without intervention.

Existing product

Cytomate™ offers a wide range of capabilities concerning cell growth measurements. Our goal was to design a similar device but much cheaper given the fact that a common microscope webcam will be used.
cytomate.jpg
Figure 1: Cytomate

Part One: Experimental Procedure

The first step was to define the parameters which would ensure that a clear image of the cell culture would be acquired by the selected camera (type). After conducting various experiments in the lab we came to the conclusion that the following parameters were vital to achieving our goal:
  • Position of the camera: vertical or horizontal. The latter was aborted due to inability of focusing properly and getting a clear image.
  • Angle of the camera: In order to achieve a better image contrast, the camera should be positioned with an angle of ~75° in respect to the vertical axis.
  • Maximum distance between lens and specimen should be 9 mm vertically.
  • Light position should be above the specimen, coaxial with the camera lens and the minimum vertical distance between them should be approximately 65 mm.

cells-first.jpg
Figure 2: First Image Acquired

Part Two: The device

Requirements


The main purpose of the device is to house and protect the microscope camera from the surrounding environment and also provide the ability of monitoring the cell culture under different conditions.

Specifications


In addition to the specifications discussed above, the device should be designed to be practical, adjustable and friendly to use. To achieve this, the device gives the ability to:
  • Manually adjust camera focus easily
  • Configure light intensity
  • Use of both flask and Petri dish (2 sizes)
  • Examine different areas of the cell culture through fitting geometry.






Sxedio.png
Figure 3:Design Model

sxedio 2.png
Figure 4: Exploded View

Software Development


An image processing code was developed in Matlab Environment. Its aim was to analyse a certain snapshot taken from the microscope camera and to calculate the confluency of the cell culture. The code is taking advantage of the black and white options offered by Matlab. Various filters are used in order to enhance the picture. During the process the image is transformed in a black and white image, whereas the white regions represent the cells. Now the confluency can be calculated easily as the percentage of the area of the white region in respect to the area of the whole picture. Dinstictive pictures of the various stages of the image analysis are presented below.
cells final exp.png
Figure 5: Initial Image taken from the camera


im_an1.png
Figure 6: Black and white Transformation


im_an2.png
Figure 7: Filled white areas.

Confluency: 0.3047

GUI (Graphic User Interface)
A user-friendly interface was created.It provides the following options :
  • Camera preview
  • Real-time chart confluency(samples)
  • Set date and time to finish live feed.A text file is created which contains confluency for every snapshot taken
  • Image capture which calculates confluency

gui.PNG


Building the device

All of the parts were 3D-printed except from the base, the seal and the focus wheel which were laser-cut. An appropriate groove was created to ensure the insulation of the camera. Each part was colour-sprayed for the same reason.

 τίτλο.png
Figure 8 : The Device

20150707_130612.jpg

Figure 9 : Device in operation

Results

To test the device in actual condition we performed a final experiment, in which the device was placed inside the incubator for a week. The results of the experiment were crosschecked with the estimation of the lab’s biologists and are shown below:

contime2.png
Figure 10 : Results (Confluency(Time))