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Revision as of 09:00, 16 September 2015

Product

Introduction

我們認為把關食安的權利可以普及到每個人手上,於是我們設計一項產品,把有檢測毒物基因片段的大腸桿菌包埋成微膠囊放置於小型離心管中,我們也有設計生物安全機制,並存放於一級實驗室*中,提供民眾可以將油品送至實驗室檢驗,讓民眾能更快速的檢測,同時要讓政府有線索可以稽查,達到了低成本、省時間、高效率的檢測機制。台灣有125間大學有一級實驗室,北台灣有66間大學有一級實驗室。

Product Design

  1. 離心管分為左右兩部分,以隔板隔開。紅管為測試管,壓下即可將管內測試用銅離子加入微膠囊中,若有發出綠色螢光則代表大腸桿菌仍存活;若無,則代表此管無法使用,藍管為刺破管,壓下即可刺破殼聚醣始油直接進入微膠囊層。
  2. 微膠囊(微粉末狀): 微膠囊為本產品最重要的環節,此微膠囊經由冷凍乾燥後水分減少所製成,一旦接觸到任何含有重金屬,苯騈芘或黃麴毒素成分,便會發出綠色螢光(GF),用以檢測食用油中含有的有害物質。不用難搞的正式檢驗程序,或花大錢只為檢測一項家中食用油品,輕鬆簡單便宜的檢測。
  3. 夾雜在過碳酸鈉以及微膠囊之間的殼聚醣: 殼聚醣極易溶於醋酸,對於吸附cooper (II) ion有極大作用
  4. 最下層過碳酸鈉:過碳酸鈉,又稱為過氧碳酸鈉,固體為過氧化氫,是碳酸鈉和過碳酸鈉氧化氫的加成複合物,過碳酸鈉具有無毒,無臭,無污染等優點,過碳酸鈉還具有漂白,殺菌,洗滌,水溶性好等特點。在商業用途方面,通常用硫酸鹽和硅酸鹽等物質加以包裹,得到包衣的過碳酸鈉來提高在洗衣粉配方對於存儲穩定性的要求。

Instruction of Product Safety

  • Microcapsule
  • 我們利用固定化技術,將大腸桿菌包埋於微膠囊中,避免大腸桿菌汙染環境。

  • Chitosan
  • 當殼聚醣固化成膜,放入微膠囊的上下兩層,達到保護微膠囊不外露、不受破壞的作用。

  • Sodium percarbonate
  • 殺菌原理:我們將醋酸加入溶解殼聚醣後會產生水,當水流至下層就能觸發過碳酸鈉,過碳酸鈉粉末接觸到水變成過氧化氫,其具有強的氧化性,能把菌殺死[5],此為殺菌機制。

Experiment Design

1. Immobilization

1.1 Compare the effect of different immobilization methods on microcapsules’ patterns

We chose three methods to immobilize E.coli. Then we made a pre-test to ensure each method’ feasibility, including immobilization materials and equipment.

1.1.1Procedure
PVA(Polyvinyl alcohol)-SA(Alginate)
  1. Pour some solution into beakers.
  2. Draw certain amount of 8%PVA-1%SA and add it into 3%BA(Boric acid)-1%CaCl2.
SA(Alginate)
  1. Pour some solution into beakers.
  2. Draw certain amount of 8%PVA-1%SA and add it into 3%BA(Boric acid)-1%CaCl2.
ACA(Alginate & Chitosan)
  1. Pour some solution into beakers.
  2. Draw certain amount of 1.5%SA and add it into 100mmol/LCaCl2
  3. Throw the microcapsule into 0.3%Chitosan.
  4. Throw the microcapsule into 0.15%SA.
  5. Use syringe to inject sodium citrate in the microcapsule.
1.1.2 Result
1. Different materials of immobilization

We decided to apply only SA and ACA materials to our experiment, and we will delete step e. of ACA because it’s infeasible.

2. Comparison of syringe and pipet

We decide to apply syringe to our experiment because syringe has a better effect on microcapsules’ patterns than pipet.

1.2 Compare the effect of different preserving temperatures of microcapsules on E.colis' survival

We chose three common preserving temperatures to carry out our experiment, including room temperature 25℃, cooler compartment 4℃, and freezer compartment -18℃.

1.2.1 Procedure
  1. 把菌液包埋起來,放置攝氏-18,4,25度的環境中
  2. 每隔48小時進行破囊,並取出菌液培養至固態培養基上,後放入攝氏37度的環境中培養
  3. 再過48小時後數菌
1.2.2 Result

WE HAVEN’T FINISHED

2. Safety

2.1Thickness of Chitosan

3. Freeze-dried & Heavy metal absorption of chitosan

3.1 Compare the effect of freeze-dried and oven-dried chitosan on heavy metal absorption

There are many kinds of heavy metal, and here we take Cu(II) ion for example.

3.1.1 Procedure
  1. prepare 1.5 g of chitosan
  2. add in 0.4 M 50 ml of citric acid
  3. use the magnetic mixer at the speed of 100 rpm to mix the mixture for 12~24 hr
  4. use the peristaltic pump to drop the mixture into 0.9 M NaOH mixture
  5. wait for 72 hr after the reaction
  6. after been washed with DI water, put the chitosan-citrate beads into the oven and dry at 35℃ for 24 hr
3.1.2 Result

Table 1: The effect of freeze-dried and oven-dried chitosan on Cu(II) ion adsorption

3.2 Compare the effect of different initial concentrations on chitosan for heavy metal adsorption

3.2.1 Procedure
  1. prepare 3.929 g of copper sulphate.
  2. add DI water to 1000 ml
  3. take out 200 ml of the mixture, and add DI water to 1000 ml
  4. add 1 g of freeze dryer-dried chitosan-citrate beads into the different concentration Cu(II) ions mixture, and mix at the speed of 100 rpm
    100 mg/L
    250 mg/L
    500 mg/L
    750 mg/L
    1000 mg/L
  5. take samples at 0 hr, 1 hr, 2 hr, 4 hr, 8 hr, 24 hr, 48hr, 72 hr
3.2.2 Result

The higher the concentration is, the better the chitosan-citrate beads’ adsorption will be; but the percentage of adsorption will be lower

Reference