The Epitech™ 1002 Epidermal Harvesting System
Supporting Medicine Using the Suction Blister Method
Figure 1 – Epitech Chamber
Introduction
The Epitech™ system by TARA Medical Devices supports various medical procedures by producing one or more suction blisters in a controlled fashion. This minimally invasive method utilizes a specialized chamber placed directly on the donor skin and a partial vacuum, which forces the epidermis to be gradually cleaved from the underlying dermis. Precisely controlled heat is used to accelerate blister formation without damaging the epidermal cells. Once the suction blisters are formed, one can easily harvest the raised epidermal blister roof by carefully dissecting around the periphery of the graft.1
A cross-section detailing the epidermal separation is shown in Figure 2. The separation occurs at the lamina lucida, a part of the basal lamina layer.
Figure 2 – Suction Blister Cross Section
Note the types of cells that are available within the harvestable epidermis, namely melanocytes, Langerhans cells, keratinocytes and Merkel cells. The presence of these living cells in the harvested epidermis is the key feature that allows this tissue to be used in various medical procedures.2
Figure 3 – Six 1cm diameter suction blisters produced from the Epitech system
Harvesting epidermal tissue using suction blisters has advantages compared to the most common alternative, namely, split-thickness grafts obtained by a dermatome knife (see Figure 4). Using a dermatome knife correctly requires experience, skill and precision due to difficulty in controlling the depth of the graft during the harvesting procedure. Additionally, a knife may not produce a graft with the precise thickness of skin needed. This technique also creates a new dermal wound at the donor site that may need special care and attention, with risk for chronicity, pain, or long-term treatment1. Finally, split-thickness skin grafts often produce a permanent, disfiguring scar at the donor site.
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Figure 4 – Example of a dermatome knife (Humby Skin Grafting Knife)
Harvesting epidermis via suction blister produces a pure epidermal sheet, is painless (requiring no anesthesia) and heals quickly, usually leaving no dermal scar. The epidermal sheets have several medical applications, including autografting to treat chronic wounds, vitiligo, and other skin conditions. Targeted cells in the harvested epidermis may be extracted for transplanting, called cellular grafting, and these cells may be used to treat specific skin conditions. Harvesting epidermis via suction blister is also a non-invasive method to collect epidermis for biopsies, including blister fluid to study various diseases and pharmacokinetic research. Each of these applications is described in more detail below.
Epidermal Autografts
Epidermal autografting is a grafting method that ideally uses only the epidermal layer of the skin. The epidermis is typically harvested utilizing a suction blister device such as the Epitech™ system or a split-thickness knife. When the suction blister method is used, there is minimal donor site morbidity and the process is relatively painless, allowing autologous skin grafting in an outpatient setting.
Figure 5 shows three blister caps after harvesting, ready for application on the recipient site.
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Figure 5 – Three Epidermal blister roofs on a slide coated with sterile petroleum jelly to aid in handling
Wound Care
Epidermal autografts are used to treat chronic wounds (ulcers) due to venous insufficiency, trauma, pressure, diabetes, and other causes. The ulcer is thoroughly debrided first to assist in the removal of local barriers to healing and to promote granulation tissue.1
The donor site is usually an area of unexposed skin, such as the inner thigh region, hip or buttocks. Unexposed skin is preferable, as testing has found that areas commonly exposed to sunlight typically have longer blister formation times and lower quality epidermis. The donor site is prepared by sanitizing, and hair may be removed with clippers (no shaving). After the suction blisters are formed and the epidermis has been harvested, the donor site is properly dressed with a bandage which should be changed daily until healed, usually in 7-10 days.
After placing the harvested epidermis on the thoroughly debrided wound, the wound is properly dressed, and the patient is instructed to keep the dressings dry and covered until their follow-up visit.
Vitiligo Treatment
Another use for epidermal autografts from suction blisters is to treat vitiligo. The process is like the above description, but the depigmented recipient site is prepared with an ablative fractional laser or other method to remove the existing epidermis which creates an environment to accept the donor epidermal sheets. After the epidermis is placed on the prepared de-pigmented area, a dressing is applied that typically stays on the recipient area for a week.
Please contact TARA Medical Devices for detailed guidelines regarding these procedures.
Cellular Grafting
Properly harvested epidermis has many live cells that can be useful, such as melanocytes, keratinocytes, Langerhans cells and Merkel cells. Through use of enzymes and/or mechanical extraction, these individual cells can be separated and concentrated in a suspension.
One example of cellular grafting is to treat vitiligo by transplanting melanocytes harvested from the epidermal graft to recipient depigmented areas. This differs from the epidermal autograft treatment described above in that instead of epidermal sheets being placed on depigmented areas, melanocyte cells are separated from other cells using an enzyme and then concentrated in a suspension followed by application to the prepared recipient site. A key to this process is proper preparation of the depigmented area to enable reception of the transplanted melanocytes. This is typically performed by removing the epidermis of the recipient area with a laser or dermabrasion.
Suction Blister Biopsies
Certain skin conditions can be diagnosed through an epidermal biopsy with epidermis collected using the suction blister method. In some cases, a suction blister skin biopsy method can be used in place of traditional biopsy methodologies as a minimally invasive, non-scarring skin sampling technique. The harvested tissue is examined under a microscope and analyzed for various factors like the location of skin layer separation or the presence of specific antibodies. This method can be used to analyze blistering skin conditions, assess skin damage, evaluate nerve function, or investigate other skin conditions.3
Interstitial Fluid Collection
As a suction blister is forming, it fills with interstitial fluid extracted from the dermis. Interstitial fluid is common in the body and normally fills the spaces around cells. This fluid serves crucial functions, including transporting oxygen and nutrients to cells while removing waste products. The suction blister process slowly extracts this bodily fluid from around the cells in the dermis but remains contained within the blister by the epidermis. After the blister is fully formed, this fluid may be aspirated and analyzed.
Interstitial fluid serves as an important tool for medical diagnostics, as it mirrors the nutrient composition of blood and can assist in monitoring conditions like diabetes through continuous glucose monitoring. It also plays a role in oncology, as it contains proteins and biomarkers that can provide insights into tumor characteristics and aid in the development of targeted treatments.4
Interstitial fluid can be centrifuged to retrieve cells from the epidermis and upper dermis for flow cytometry, single-cell RNA sequencing, cell culture, and more without the need for digestion protocols. In addition, the blister fluid can be used to measure soluble proteins and metabolites.3
The interstitial fluid may be aspirated with a syringe, as shown in Figure 5.
Figure 6 – Aspiration of suction blister
Pharmacokinetics
Another common use of interstitial fluid is to assist in pharmacokinetics, the study of how drugs are absorbed and flow throughout the body. Since interstitial fluid comes from the outside the blood vessel barrier, it can indicate efficacy of drug passage from blood to cells throughout the body.
Conclusion
Suction blisters such as those produced by the Epitech™ system are very useful for many medical procedures involving dermatology, oncology, wound care, and pharmacokinetics, to name a few. Use of the Epitech™ system ensures that the suction blisters are quickly formed without pain and without damage to the epidermal tissue or the interstitial fluid. For more information, please contact us.
Sources
1. Dolce M, Brown N, Dolce K. Treating Chronic Lower Extremity Ulcers with Autologous Skin Grafting. Podiatry Today. 2025; March, Volume 38, Issue 3.
2. Fierro AL, Hijazi N, Bridge M, Lantis JC 2nd. In-Office Skin Grafting for Lower Extremity Wounds. Surg Technol Int. 2025 May 19;45:sti45/1864. Epub ahead of print. PMID: 40388920.
3. MacDonald EA, Katz EL, Pearson TF, Harris JE. Performing Suction Blister Skin Biopsies. Curr Protoc. 2024 Jun;4(6):e1073. doi: 10.1002/cpz1.1073. PMID: 38924322; PMCID: PMC11210708.
4.Source: https://www.ebsco.com/research-starters/science/interstitial-fluid