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 A comedo is when a follicle is clogged with dirt, bacteria, and dead skin cells.  Blackheads- a partially blocked pore which allows some of the dead.

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Presentation on theme: " A comedo is when a follicle is clogged with dirt, bacteria, and dead skin cells.  Blackheads- a partially blocked pore which allows some of the dead."— Presentation transcript:


2  A comedo is when a follicle is clogged with dirt, bacteria, and dead skin cells.  Blackheads- a partially blocked pore which allows some of the dead cells and dirt to escape. The black color is a result of a reaction between the skin’s melanin and oxygen.  Whitehead- a completely blocked pore, clogged with oil, dead skin cells, and bacteria.  Pustule  Papule  Nodule  Cyst

3  Each hair follicle on the skin contains a sebaceous gland which produces sebum. Sebum is an oily substance that coats the skin and protects it.  Acne is formed when dead skin cells and dirt clog the pore and then sebum starts to build up in the follicle. Then propionibacterium acnes (P.acnes) “…infects the sebum and multiplies inside. The follicle gets filled with sebum and the bacteria that are multiplying” ("Acne: How Acne Forms?").

4  What’s the affect of acne medication on the growth of S. epidermidis bacteria?

5  Acne medication with the highest percent of the main acne killing ingredient will have the largest effect on the growth of bacteria and therefore the largest zones of inhibition

6  3 different acne medications  6 Petri dishes prepared with agar  6 sterile swabs  16mL of sterile water  Culture of S. epidermidis bacteria  24 discs  4 empty Petri dishes  4 pipettes  Incubator  Gloves  Lab coat  Balance  Tweezers  Tape  Bunsen Burner  Timer  Goggles  Sharpie marker

7  Salicylic Acid 2%  Alcohol Denat. 38%  Hamamelis Virginiana (Witch Hazel) Water  Water  Polyquaternium-37  Glycerin  Glycolic Acid  Butylene Glycol  Cyclohexasiloxane  C12-15 Alkyl Lactate  Cyclopentasiloxane  Cetyl Lacate  Polysorbate 20  Portulaca Oleracea Extract  Sodium Benzotriazolyl Butylphenol Sulfonate  Cocamidopropyl PG- Dimonium Chloride Phosphate  Sodium Hydroxide  Sodium Chloride  Bisabolol  Benzalkonium Chloride  Yellow 6  Red 40  Fragrance (988-145)

8  Benzoyl Peroxide 2%  Water (aqua)  SD Alcohol 39-C  Methylpropanediol  Triethanolamine  Carbomer  Lactic Acid  Willow Bark Extract  Phenoxyethanol  Ethylhexylglycerin  Triclosan  Tetrasodium EDTA  Propylene Glycol

9  Benzoyl Peroxide 10%  Water  Laureth-4  Carbomer  Triethanolamine  Hydroxypropylmethylcellulose  Disodium EDTA

10  Independent variable: The different types of acne medication  Dependent variable: The size of the zones of inhibition  Control variable: A disk soaked in 4mL of sterile water and no acne medication  Constant variables: The type of bacteria, the same amount of acne medication and water in each solution, the same temperature of the surrounding air, the same amount of time each disc soaked in the solution, the same amount of time kept in the incubator, and the same kind of Petri dishes and discs.

11 1. Filled 6 dishes with agar using sterile technique 2. Hydrated bacteria using sterile technique 3. 24 hours later; label all 6 Petri dishes. 4. Weigh 1 gram of the first acne medication and mix it with 4mL of sterile water in an empty Petri dish. 5. Repeat step 4, 2 more times using a different acne medication each time. 6. Put 4mL of sterile water in an empty Petri dish. 7. Put 6 discs in each of the 4 empty Petri dishes with 3 different acne medications and one with just sterile water. 8. Let discs soak.

12 9. Swab S. epidermidis bacteria on the agar using sterile technique. 10. After discs soak for 20 minutes, put a disc from each of the 3 mixtures and one of water in each of the 6 Petri dishes with bacteria. 11. Each dish should have 4 discs in it. 12. Tape Petri dishes. 13. Let the 6 Petri dishes sit in the incubator for 24 hours. 14. Measure the zones of inhibition after 24 hours. 15. Autoclave the dishes and then dispose of them.


14 NeutrogenaAcneFreeCVSWater Trial 1 20503010 Trial 2 20503010 Trial 3 20403010 Trial 4 20402510 Trial 5 20402510 Trial 6 25402510 Average 20.8333333343.33333327.510 StDev 1.8633899814.71404522.50


16 SUMMARY GroupsCountSumAverageVariance Column 1612520.833334.166667 Column 2626043.3333326.66667 Column 3616527.57.5 Column 4660100 * P-value = 5.08E-13 * T-Test : * Neutrogena v. CVS = 0.0007447 * Water v. Neutrogena = 1.3715E-07

17  These results will most likely not be the same if a different type of bacteria is used.  Even though sterile technique was used throughout the experiment there is always the risk of contamination somehow.  Medications that had volatile materials such as alcohol may have evaporated under incubation.

18  To further this experiment, different bacteria or a combination of dead skin cells and dirt could be used.  In addition, acne medication with other types of main ingredients could be used as well as prescription medication or natural remedies.

19  In this experiment, the AcneFree brand gel with 2% Benzoyl Peroxide had the largest zones of inhibition compared to the CVS brand gel which contained 10% Benzoyl Peroxide and the Neutrogena brand gel which contained 2% Salicylic Acid.  One possible explanation for why Benzoyl Peroxide did better than Salicylic Acid in this experiment is because Benzoyl Peroxide acts as an anti-bacterial that removes bacteria in the follicles while Salicylic Acid slows down the process of skin cells shedding inside the hair follicle which clogs the pores.  The AcneFree brand which only had 2% Benzoyl Peroxide might have done better in killing the bacteria than the CVS brand with 10% Benzoyl Peroxide because the AcneFree Brand contained alcohol which is very effective in removing dirt and oil from the skin and preventing the growth of acne.

20  "Acne: Common Causes." N.p., n.d. Web. 21 Nov. 2010..  "Acne: How Acne Forms?" N.p., 14 June 2006. Web. 21 Nov. 2010..  "How Acne Develops." N.p., 1998. Web. 18 Nov. 2010..  "Ingredients that Causes Acne." Quick Acne Remedy, LLC, 2003. Web. 16 Nov. 2010..  Mayo Clinic staff. "Over-the-counter Acne Products: What Works and Why." N.p., 16 Apr. 2010. Web. 18 Nov. 2010..  "6 Common Ingredients in Acne Products You Should Know." N.p., 2006. Web. 18 Nov. 2010..  "What Is Acne?" N.p., n.d. Web. 1 Dec. 2010..

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