Artificial SkinArtificial SkinArtificial Skin Victoria Tang

Thomas Mak

Louise Tsang

Zero Wong

Iris Ting Background The functions of skin are of vital importance to human, and these can be achieved because of the unique structure of skin.

Structure of Skin Importance of Skin

Fig. 1 Basic Structure of Human Skin [1]

Preventing loss of

moisture

Function of Skin Providing protective

barrier

Reducing the

harmful effect of UV

radiation

Acting as sensory

organ

Regulating body

temperature

Fig. 2 Function of Human Skin [2]

Skin is a major organ of our body to sustain life. If damages of skin occur without any proper medical treatment, several serious problems

may arise.

Medical Problems[3]

Skin can be damaged or lost by 1. Severe burns (By fire, heat, electric current, corrosive chemicals, etc.)

2. Mechanical skin trauma (Being cut by hard or keen objects, rubbing with rough surface, etc.)

3. Skin diseases (Skin cancer, skin putrefaction due to infection, etc.)

Therefore artificial skin is needed for transplantation.

Problems raised without the usage of artificial skin

1. Severe damage to large area of skin leading to dehydration, and

2. Infections,

3. Resulting in death

Problems raised by traditional skin graft Traditional skin graft is adopted to replace skin of wounded area by using skin from other parts of

patients' body (such as thigh) or from a different person/cadaver. Problems raised are as follows:

1. Insufficient skin available for transplantation

2. Possibility of rejection due to immune response , or

3. Infection during the surgery

So artificial skin can provide essential skin functions and at the same time, have less problems raised

compared with the traditional skin graft’s method, which as a whole benefits patients suffering from

different degrees of skin loss. Different types of artificial skin are also designed to cater for patients’

needs.

Solutions

Acknowledgements We would like to express our heartfelt gratitude to Dr Barbara Chan and Dr Josephine Ip for their professional expertise, valuable opinions and above all,

patient guidance. Without their kind support, this project would not have been done smoothly.

Fig. 3 Artificial skin (left) compared to section through hu-

man skin (right).

Fig. 4 Skin with Capillary Wall

Permanent Skin Graft

Developed from human cells [4]

Procedures [5],[6]:

1. Extracting skin from other parts of body

(e.g. foreskin)

2. Separating skin cells (fibroblast) from

dermal layer

3. Quarantining the cells by testing for

viruses and other infectious pathogens

(e.g. HIV, hepatitis B and C)

4. Growing the cells on mesh scaffolding

5. Thawing, expanding and storing the

cells

6. Implanting it to patients’ wounds

7. Waiting until new blood vessels grow in

the implanted skin. (Approximately one

week’s time)

8. Recovering

Temporary Skin Graft [9]

To protect the wounds while healing

Able to be removed after recovery

Procedures:

1. Taking cells from unwounded epidermal

layer

2. Culturing the cells as large sheets

3. Making skin graft from the cell sheets

4. Applying on wounds to stimulate the

growing of new dermis[10]

5. Waiting until the curing process

completes

6. Removing

the protective

upper layer

Spray-on Skin [7]

Producing enough cells to cover major

burns in 5 days

Procedures: [8]

1. Taking healthy skin sample from patient

2. Splitting the sample in laboratory to

separate out the surface cells

(keratinocytes)

3. Culturing cells for two to three weeks,

and making up into a suspension

4. Putting other skin cell tissue through a

meshing machine, meek mesher, and

then cutting the skin sample into tiny

squares

5. Spraying the cultured cells onto small

pieces of tissue and combining them to

create new skin for patient

The artificial skin aims to substitute traditional skin graft which has more flaws. There are three common types of artificial skins:

(1) Spray-on skin (2) Permanent skin graft (3) Temporary skin graft

There are three types of artificial skin but no fixed formulae are set for different level of skin loss. In other

words, artificial skin is used, whether it is only a single type or a mixed of skin grafts, solely on a case-by-case

basis and depending on the health conditions of patients.

Fig. 6 The treatment helped heal severe burns on an

elderly patient's legs [11]

Fig. 7 Skin from a factory

Fig. 5 human skin hair [12]

Case Studies

Cases Patient Solution used Photos before the

surgery

Photos after the

surgery

1 Male

5 years old

Suffering from

Necrotizing

fasciitis (a serious

infection that causes

cell tissue to be

rapidly destroyed) of

right upper limb

Permanent skin graft

2 Male

62 years old

Serial change

develop ulcer(a

sore area on the

outside of the body

or on the surface of

an organ inside the

body which is painful

and may bleed or

produce poisonous

substance) at

center

Temporary skin graft

Fig. 8,9 Permanent skin graft in culture

Fig. 10

Fig. 11,12 Permanent skin graft applied on the wound

Fig. 13

Fig. 14,15 Wound with bone exposed

Fig. 16,17 The wound is recovering after the apply of

temporary skin graft

Pros and Cons

Although artificial skin can help patients to regenerate their skin or can perform skin’s function, it still has its drawbacks.

For the three types of artificial skin, they share some common advantages and

disadvantages compared with that of traditional skin graft. But in general these two

methods still possess some strengths and flaws in common, as shown in the last row of

the table.

Pros Cons Possessing regenerating power Long recovery time

Real skin resemblance Expensive[13]

Unlimited supply Fragile [14]

Reduced scarring[14] Inability to be immediate substitute

Low chance of immune response or infec-

tion

Skin functions Impairment (sensations,

pressure, etc)

Future Development

Although there are still some imperfections like long recovery time, the ability to regenerate and

the unlimited supply of skin really solve many problems that were headaches of surgeons. So it is

believed that the advantages actually outweigh the disadvantages to a large extent.

For different sizes of wounds, different types of methods of healing will be used. For example, (i) When the size of the wound is

larger than a normal size of a palm, permanent skin graft will be used, if not, (ii) temporary skin graft will be used instead. For

the (iii) spray-on skin method, it is still being studied and thus not being practiced.

The following are 2 case studies using artificial skin:

Case 1 : The use of permanent skin graft on a patient with large amount of own skin being removed.

Case 2 : The use of the temporary skin graft on a patient with part of skin on leg being debrided (removal of dead, contaminated tissue) .

There are still some downsides of artificial skin as mentioned, but there have been many researches

being done to rectify the flaws and to perfect this technology.

1. Growing skin from stem cells in human hair [15]

This utilizes the differentiation ability of stem cells, but the technology for monitoring such processes is still

being studied.

2. Producing a fully-functional, lab-produced artificial skin graft[16] It is hoped that artificial skin could be made solely in lab, with which is fully functional and possesses all

blood vessels and nerves.

3. Creating an automated production line process for manufacture[17] The former two form a backdrop under which a manufacture plant could be set up for mass production of

skin grafts which cater for everyone where no immune responses would be triggered.

Fig. 18 A man holds a piece of artificial skin from Integra.

Grafts would be placed atop this piece.

Fig. 19 A surgeon performs a skin transplantation surgery using

artificial skin

References [1] Degree of burn. Available at : http://www.burnsurvivorsttw.org/burns/degree.html. Accessed April 13, 2010.

[2] Bensouilah J. and Buck P. Skin structure and function. Aromadermatology. Radcliffe;2006: 1-10.

[3] Wikipedia, Artificial skin . Available at: http://en.wikipedia.org/wiki/Artificial_skin. Accessed April 17, 2010. [4] Metro, Health Report. Available at: http://www.hku.hk/facmed/healthedu/issue29/issue29.pdf . Accessed 17 April, 2010.

[5] People, New Transplantation. Available at: http://www.people.com.cn/BIG5/keji/1057/2645068.html. Accessed 17 April, 2010.

[6] Answers .com, How is artificial skin made? Available at: http://www.answers.com/topic/artificial-skin-2. Accessed 17 April, 2010. [7] Langer R. and Vacanti JP . "Tissue Engineering," Science, May 14, 1993, pp. 920-921.

[8] Spray on Skin. Available at: http://www.biotechnology-innovation.com.au/innovations/pharmaceuticals/spray_on_skin.html. Accessed April 18, 2010.

[9] What is Artificial Skin? Available at: http://www.wisegeek.com/what-is-artificial-skin.htm. Accessed April 18, 2010. [10] Langer R. and Vacanti JP. "Artificial Organs," Scientific American, September 1995, pp. 130-133.

[11] BBC NEWS| Health| Spray-on cells treat severe burns. Available at: http://news.bbc.co.uk/2/hi/health/4208746.stm. Accessed April 18, 2010.

[12] McCarthy M. "Bio-engineered tissues move towards the clinic," The Lancet, August 17, 1996, p. 466. [13] Smith C. Artificial skin offers genuine hope. Seattle Pi. 2001. Available at: http://www.seattlepi.com/local/burn231.shtml. Accessed 10 April, 2010.

[14] Edmonds M. How Lab-grown skin works. Howstuffworks. Available at: http://health.howstuffworks.com/lab-grown-skin2.htm. Accessed 10 April, 2010.

[15] Fraunhofer – Gesellschaft. Growing Artificial Skin From Hair Roots. ScienceDaily. 2008. Available at: http://www.sciencedaily.com/releases/2008/01/080104140344.htm. Accessed 10 April, 2010. [16] HowStuffWorks Anatomy Web site. Available at: http://health.howstuffworks.com/skin-care/information/anatomy/skin-graft5.htm. Accessed 10 April, 2010.

[17] Fraunhofer – Gesellschaft. Production Line for Artificial Skin. ScienceDaily. 2008. Available at: http://www.sciencedaily.com/releases/2008/12/081209100838.htm. Accessed 10 April, 2010.