The Biomask is a standard polyurethane mask ^[7] that will aim to provide a clean environment for regeneration of new skin. The hope is that it will increase healing time of facial skin, decrease scarring as well as the number of surgeries a patient would have to endure.

Robert Hale, an outstanding plastic surgeon, is credited with developing the idea of the Biomask, which is aimed to aid in facial regeneration. In 2003, Hale joined the U.S. Army and became one of the top facial trauma surgeons ^[7]. Throughout his service, he quickly came across many challenges when dealing with the warfare wounds of the 21st century. Hale once said, “I’m tired of using tools from my grandfathers war” ^[7]. This frustration stemmed from the fact that the procedures he performed often involved using other body parts and resulted in the formation of scar tissue. Hale would use tongues to make lips, and parts of leg bones to form jaws ^[6]. With the technology advancements in medicine that are available today, Hale soon realized that facial regeneration was lagging behind. One victim in particular, Todd Nelson, was an eye opener for Robert Hale.

Todd Nelson, a U.S. soldier, endured a traumatic facial injury in 2007, when he was hit with a blast from a suicide bomber ^[7]. The blast caused severe damage to Nelson’s face, melting off his skin, crushing his facial bones, ripping through his eye, and removing his right ear ^[6]. Nelson was then flown to San Antonio, where Robert Hale and his medical team attempted to treat Nelson’s horrifying wounds. After dealing with bacterial biofilm formation, a skin graft rejection, and performing over 50 operations, Hale was desperate to develop a better way for treating traumatic facial injuries. This led to the development of the Biomask.

Hale was determined to find a way to apply already existing technology that was used to treat body wounds to facial injuries. Synthetic sheets of skin, called Integra, were covered with an anti-biotic sponge layer and placed over flat regions of Nelson’s injured body ^[7]. In addition, fluid that accumulated due to inflammation was removed from Nelson’s wounds through tubes that were hooked up to a suction pump ^[7]. This technique resulted in reduced swelling and inflammation, which ultimately led to reduced scarring. Within weeks of applying the Integra, the synthetic skin was absorbed by Nelson’s wounded tissue and acted as the deepest layer of skin; the dermis. Hale and his team then removed the top layer of the Integra sheet and replaced it with an epidermal skin graft from Nelson’s back ^[7]. Despite the promising results of this procedure, it is unable to treat traumatic facial wounds and led to many complications when attempted on Nelson’s face. This urged Hale to come up with a new way to treat facial injuries.

Robert Hale presented the Army with his idea of the Biomask, which takes existing technology and integrates it into a simpler method of providing treatment for severe facial injuries. Instead of performing multiple surgeries, which result in scar tissue, pain and often times severe infections, Hale developed the idea of a custom fitting mask that would deliver antibiotics, stimulate cell growth and regeneration and dramatically reduce inflammation caused by microbial pathogens ^[7]. To do this he borrowed the existing methods of skin regeneration performed on Nelson’s body to design the Biomask. Eileen Clements, an engineer at the University of Texas, was called on board to develop small wound vacuums, similar to the existing ones, which would be able to fit inside the Biomask ^[7]. In addition, Hale plans to incorporate the discovery of a molecule found in human saliva, by Dr. Kai Leung, that prevents the growth of bacteria ^[7]. A synthetic version of this molecule would be administered via the Biomask to prevent biofilm formation and reduce the possibility of infection. Lastly, Hale plans to use the idea of “spray-on skin” developed by plastic surgeon, Fiona Wood, to improve facial skin regeneration ^[7]. The idea is to remove a small portion from the patient’s scalp and extract stem cells, which can then be applied to the wounded area of the face ^[7]. This would allow skin regeneration without rejection or removing large sections of the skin from other body parts. Overall, the Biomask would merge existing technology and apply it directly to the advancement of facial regeneration.

Materials used for the Biomask are still under development and testing. For the initial step of the Biomask, a pliable polymer mask is used as a base where in the biological, mechanical, and electrical parts are built in ^[5].

The main strategy is to integrate a Vaccum–Assisted Closures or “wound VACs” into this pliable polymer mask. Current VACs are simple antibacterial soaked sponges (polyurethane), that are placed into the wound and sealed ^[5]. This is then paired with a tube who’s one end runs through the sponge and the other end is connected to a vacuum pump which provides the negative pressure area and can be set to be on continuously or in short bursts ^[8]. The purpose of this this system is to remove fluids and infectious materials, protect wound environment, and promote per-fusion and a moist environment ^[8]. The difference between the Biomask and the regular VACs lies in the Biomask’s ability to be applied on any surface area. Current VACs require a relatively flat block of sponge that is set on a smooth surface of the skin ^[8]. This is required to help provide negative pressure evenly over a specific area ^[8]. However this is impossible to achieve on the face with its complex features such as the nose and eyes. The idea for the Biomask is to be able to fit on such surfaces using the help of miniature VACs that come along with mechanical based sensors ^[7]. With current technology it is also quite easy to create a scan of a person’s face and create a personalized custom face mask/wound VAC that will fit anyone perfectly ^[5]. The mechanical sensors will then be used to detect any change on the surface of the face, such as during wound healing, and will re-adjust the pressure applied to the surface by inflating a tiny balloon (Example above) ^[8]. Moreover, along with keeping this negative pressure over the wounds they can then allow for easy access to release antibiotics and other anti-inflammatory drugs inside the mask to keep the wound clean ^[7].

Neodermal matrices are biodegradable, biosynthetic polymer matrices that are dense on the top side and porous at the bottom. This design allows it to mimic the skin layer and allow both protection from bacteria like an epidermis, and promote growth of vasculature underneath ^[2]. Current examples include IntegraTM which are “cut-to-fit” bilayer sheets that use collagen and other molecules derived from cow and shark tissues for the porous layer ^[7]. A silicone top layer is then used to act as the epidermis to keep bacteria out ^[7]. Although this technology exists now, the issue is that the biopolymer sheets are not custom built to fit over the intricate topography of the face and do not have the correct thickness. A possible solution to this problem involves using a 3-D bioprinter to take scans of the face and convert them into stereolithography models ^[5]. These 3-D digital models will allow for precise construction of skin layers for any wound or burn. There have been successful prints of 10 cm2 skin sheets and even stem cells, derived from amniotic fluid, that were successfully printed to treat full-thickness skin wounds in mice ^[10].

After developing an optimized wound bed, Dr. Hale would like to incorporate multiple skin regeneration projects. Such examples include, stem-cell dressing, targeted delivery of drugs (e.g.,statin, small molecule adhesion kinase inhibitor,novel peptide and polysaccharide compound) to promote healing and reduce scarring, face transplants, split-thickness skin grafting, and spray-on skin ^[5][8].

Spray on skin is a treatment used on burn victims to regrow skin using the patients own skin cells in a regenerative process. This treatment accelerates healing, minimizes scar formation, eliminates tissue rejection, and helps reintroduce pigmentation to the skin ^[1]. It was originally developed in Perth, Western Australia, by Dr. Fiona Wood ^[3]. The process involves using an aerosol system to deliver cultured skin cells to larger wounds more evenly ^[3]. This method takes a postage stamp-sized piece of skin from the affected patient. Contained in the skin sample are basal stem cells and melanocytes (cells that give skin its colour and texture) ^[3]. The sample is soaked, for half an hour, in an enzyme, trypsin, in order to dissolve the structural material holding the cells in place. These cells quickly adhere to the wound, proliferate, promote healing, and give skin colour ^[7]. Using spray on skin is simpler than grafting large pieces of skin from other parts of the body, and Dr. Wood discovered that if the wound is treated within 10 days, scarring could be reduced significantly ^[3]. Gerlach et al. also conducted a study in 2011 where they treated eight burn patients with spray on skin cells. They discovered that the mean time of epithelial regrowth was 12.6 days ^[6]. Due to the benefits of this technique, Dr. Hale plans to incorporate this idea into the Biomask to allow for regrowth of skin similar to that of the original facial skin.

Semlali et al., 2011, investigated whether peptides produced by human oral epithelial cells had antimicrobial properties. Due to the rising issue of bacterial drug resistance, the main goal of this study was to isolate and develop a synthetic alternative. The researchers isolated defensins, which are normally produced by epithelial cells, and act to eliminate microbial growth ^[9]. Next they synthetically produced a similar alpha-helical decapeptide, called KSL and it’s analog KSL-W, which exhibits analogous antimicrobial characteristics. An additional advantage of this synthetic peptide is that it targets a wide range of microbes, including non-oral pathogens ^[9]. This means that it has the potential to replace current antibacterial drugs, which are no longer effective. The researchers also tested the KSL decapeptide with a benzalkonium chloride solution and found that it dramatically decreased biofilm formation ^[9]. These results show that the KSL peptide and its analog have significant potential as new antimicrobial drugs. In addition, the study by Semlali et al., 2011, also concluded that the synthetic peptide was not toxic towards human epithelial tissues. Therefore, Robert Hale plans to incorporate KSL-W peptides into the Biomask to prevent biofilm formation over open wounds. This would also prevent scar tissue formation and drastically improve the healing process.

The primary function of the Biomask is not to regenerate lost skin, but to provide a clean environment for new skin to regrow while providing a method to prevent infection and inflammation. It also prevents biofilms from growing, minimizing scarring ^[7].

The following explains the five-step process of how the Biomask works:

Step 1: The patient's wounds are cleaned thoroughly and dead tissue is removed before applying the Biomask.

Step 2: The patient’s head is sealed inside a standard-size polyurethane Biomask. Drugs such as antibiotics, analgesics, anti-inflammatories, and growth factors are pumped in for the first 24 hours, in order to prevent infection and reduce pain.

Step 3: The mask is then connected to a negative pressure wound therapy device. Negative pressure is applied for 48 to 72 hours.

Step 4: Once the negative pressure is applied, the mask is removed to apply skin graft, artificial skin, or spray on skin cells, and then placed again, this time for seven to fourteen days. The shell serves as protection and holds the graft in place, while the low negative pressure stimulates cell and blood vessel growth to help graft firmly take place ^[7].

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[1] Avita Medical (No Date). Recell Spray on Skin. Retrieved from http://www.avitamedical.com/index.php?id=5&ob=1

[2] Beumer, G. J., Van Blitterswijk, C. A., & Ponec, M. (1994). Biocompatibility of a biodegradable matrix used as a skin substitute: an in vivo evaluation. Journal of biomedical materials research, 28(5), 545-552

[3] Biotechnology Australia (No Date). Spray on Skin. Retrieved from http://www.biotechnology-innovation.com.au/innovations/pharmaceuticals/spray_on_skin.html

[4] Bland, E. (2009, November 23). Spray-on skin speeds up healing burns. Retrieved from http://www.abc.net.au/science/articles/2009/11/23/2750438.htm

[5] Cheng, X., Yoo, J. J., & Hale, R. G. (2014). Biomask for skin regeneration.Regenerative medicine, 9(3), 245-248.

[6] Gerlach, J. C., Johnen, C., Ottomann, C., Brautigam, K., Plettig, J., Belfekroun, C…. & Hartmann, B. (2011). Method for autologus single cell isolation for regenerative cell spray transplantation with non-cultured cells. 34(3), 271-279. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/21480179

[7] Gross, L. (2014, August 6). New hope for soldiers disfigured in war. Retrieved from http://discovermagazine.com/2014/sept/11-face-of-hope

[8] Sam Utari. (2013, April 3). Col Robert Hale at UTARI Biomedical Symposium [Video file]. Retrieved from https://www.youtube.com/watch?v=38CUaxkfUCY&list=FL-D7vWRsJLmcgMh57DLp0_g&index=1

[9] Semlali, A., Leung, K. P., Curt, S., & Rouabhia, M. (2011). Antimicrobial decapeptide KSL-W attenuates Candida albicans virulence by modulating its effects on Toll-like receptor, human B-defensin, and cytokine expression by engineered human oral mucosa. Elsevier, 32, 859-867. doi: 10.1016/j.peptides.2011.01.020

[10] Skardal, A., Mack, D., Kapetanovic, E., Atala, A., Jackson, J. D., Yoo, J., & Soker, S. (2012). Bioprinted amniotic fluid-derived stem cells accelerate healing of large skin wounds. Stem cells translational medicine, 1(11), 792-802.