GMU:DIY Biolab “Driver’s License”/Yang Li: Difference between revisions

===1. Introduction===

1.1 anthocyanin

Anthocyanins are water-soluble vacuolar pigments. In the 1664 book Experiments and Considerations Touching Colours by chemist Robert Boyle, various edible plants are reported as visual pH indicators due to pH-responsive mechanisms in their tissues [1]. Anthocyanin is a kind of natural colorant in food and beverage industry, and has been found to possess anti-inflammatory antioxidant properties [2]. It has also been researched for use as an indicator for packaging applications to detect spoilage in pork and fish products [3]. All tissues of vascular plants contain the flavonoid anthocyanin, a pigment that changes colour under varying pH solutions.

Under different pH conditions, the hydroxyl (OH) and/or methyl ether (O-CH3) groups attached to the carbon rings (figure 1) undergo reversible structural transformations and ionizations. Restructuring a molecule changes the way it ab- sorbs light, giving rise to colour changes [4].

1.2 red cabbage

"Red cabbage is rich in a number of bioactive substances, including anthocycanins"[Wiczkowski, 2012]. The method of extracting anthocyanin from red cabbage is easy and convenient.

===2. Idea===

This work is based on a research done by MIT media lab that uses organic fluid-based molecules. The molecules anthocyanin, vanillin, chitosan are used as dopants that can sense different pH values. The output is in the form of a broad spectrum of colors, odors and shapes. Based on this, the experiment focus on color changing, using kappa-carrageenan as substrate to present the reaction in a certain form. The outcome shows chemical reactions that are in daily life unreadable and unseen. What is shown here is a new design language to create new appliances. In the exhibition, color changing can be seen both in liquid and solid statues.  

===3. Methodology===

<gallery caption="Color Changing in liquid status">

File:Screen Shot 2018-01-31 at 15.12.21.png|Making pH solutions

File:4931517416494_.pic_hd.jpg|Making red cabbage indicator  

</gallery>

<gallery caption="Color Changing in solid status">

File:屏幕快照 2018-03-31 下午1.40.34.png|1.5%w/v kappa-carrageenan in deionized water   

File:屏幕快照 2018-03-31 下午1.42.02.png|color changing

</gallery>

<gallery caption="Shape Changing">

File:2018-03-31 下午1.42.36.png|4% w/v chitosan powder

File:屏幕快照 2018-03-31 下午1.43.45.png|pH2 and pH12 shape changing

</gallery>

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===References===

#[1] Robert Boyle. 1664. Experiments and Considerations Touching Colours. Project Gutenberg. 1–157 pages.

#[2] Jian He and M Monica Giusti. 2010. Anthocyanins: Natural Colorants with Health-Promoting Properties.