Day 5 - To the Lab~

We started the day straight at the Bio-lab at the Research Techno Plaza, where we carried out tests on a graphene sample. Based on our understanding, how graphene oxide in biosensors as a future application is that it will monitor the body conditions through assessing the composition of the blood in athletes. While is the body is overworking , it will release interleukin-6 which may be deadly if present in excess amount in the blood. However, a drawback is that even though an athlete may feel uncomfortable and experience fatigue during a work-out, it may not necessarily mean that there is an excess level of interleukin-6 in the body . Therefore, the rationale for using such sensor is to inform the user when to stop exercising by showing accurate information about the body.  In the set-up, we investigate how the pH of the sample changes as solutions with different pH are added to it, stimulating the conditions of a human body.

Set-up

Graphene on functionalised* silicon chip with sample

* The chip is functionalised with the use of aptes which are covalently bonded to it,  due to a difference in charges possessed by the apters and chip respectively. Therefore, liquid graphene does not come off upon mixing with solutions

 Result

 We used solutions of pH 1 to pH 13 , which mean that a strong alkali and acid will be used. Therefore, these should be handled with extra care.

Solutions with different pH

For this experiment, we used a micro-pipette,  which is a precise instrument for measuring small volumes ( to the micro scale) of liquid accurately and transferring them. The amount of solution to be withdrawn can be adjusted by the tab at the top , while there are two 'pressure points' to overcome when pressing on the plunger to eject the liquid. The first press releases liquid normally, while the second will lead to a burst of air which force the rest of the liquid out .

 Micro-pipette

After awhile, we were allowed to do the experiment on our own too! But for safety precaution, it was better that we do not touch the solutions that were too acidic. 

After that, we proceeded to another lab to test out the pH level of the various solutions. For this,we used a pH measurement machine.
We soon found out that the pH level labelled on the test tubes were not as accurate, and thus had to adjust them ourselves. For the ones that were too acidic, we add in deionised water to increase the pH level. For the one that were too alkaline, we add in deionised water to lower the pH. To increase the pH beyond 7 , we have to add a dropwise of concentrated sodium hydroxide, which must be handled with care.  

pH Measuring Machine

User's manual on the equipment

Diluting the acid

NaOH

Nearing the end, we met one of Jing Feng's teammate, who became a PhD student some months back. He was doing some experiment to investigate the  electrical resistance of gold film chips!

Next week, we'll be attending another science symposium, "Small Science Symposium", at Mandarin Orchard Hotel from Monday to Wednesday!

And do come visit the blog anytime you're free~
Thanks you!

-graphene4life