Dermal Abyss

DermalAbyss is a proof-of-concept that presents a novel approach to bio-interfaces in which the body surface is rendered an interactive display. Traditional tattoo inks are replaced with biosensors whose colors change in response to variations in the interstitial fluid. It blends advances in biotechnology with traditional methods in tattoo artistry. 

We investigated four biosensors, reacting to three pieces of biochemical information in body fluid and changes colors: The pH sensor changes between purple and pink, the glucose sensor shifts between blue and brown; the sodium and a second pH sensor fluoresce at a higher intensity under UV light.

The Dermal Abyss creates a direct access to the compartments in the body and reflects inner metabolic processes in a shape of a tattoo. It could be used for applications in continuously monitoring such as medical diagnostics, quantified self, and data encoding in the body.

 

Our Current Proof-of-Concept

Our current implementation investigates the problem space of injecting pH-, glucose-, and electrolyte-selective optical biosensors within an ex vivo pig skin model to evaluate the sensitivity, selectivity, detection range, quantitative readouts, and functionality of the biosensors.

Biosensors tattooed in pig skin and the interaction under solutions. (a) Glucose biosensor, (b) Glucose biosensor with glucose, (c) Chromogenic biosensor at pH 8.0, (d) Chromogenic biosensor at pH 7.0, (e) Sodium green biosensor tattooed in skin under visible light, (f) Sodium green biosensor tattooed in skin under UV light excitation, (g) Fluorescent SNARF sensor tattooed in skin under visible light, (h) Fluorescent SNARF sensor tattooed in skin under UV light excitation at pH 8.0. Scale bar= 1 cm.

Biosensors tattooed in pig skin and the interaction under solutions. (a) Glucose biosensor, (b) Glucose biosensor with glucose, (c) Chromogenic biosensor at pH 8.0, (d) Chromogenic biosensor at pH 7.0, (e) Sodium green biosensor tattooed in skin under visible light, (f) Sodium green biosensor tattooed in skin under UV light excitation, (g) Fluorescent SNARF sensor tattooed in skin under visible light, (h) Fluorescent SNARF sensor tattooed in skin under UV light excitation at pH 8.0. Scale bar= 1 cm.

The concept of utilizing biosensing tattoos offers an attractive alternative for health monitoring in vivo for a range of medical complications, including diabetes, acidosis, alkalosis, electrolyte imbalance, and hypertension. Beyond health and well-being, it also serves as a novel platform for applications in quantified self, data encoding, and dynamic cosmetic displays.

Yet the path from proof-of-concept to a functional prototype— from animal testing, to clinical trials and commercial product, to regulatory approval—requires many phases of development. Each successive R&D phase is followed by new sets of challenges and research questions that require different resources, collaborations, and clinical data. The duration from one phase to another varies across research questions, expertise, funding, and the nature of the domain.

In our current proof-of-concept study, we demonstrated lateral and vertical injections in the skin to test the visibility and functionality of the optical biosensors in an ex vivo pig skin model. The lateral injections showed the visibility of the biosensors when deposited within the dermis, simulating the appearance of post-healing a tattoo. During the lateral injection process, each biosensor was visible from the surface as we varied the pH, glucose, and electrolyte concentrations over the ex vivo pig skin model. Vertical injections emulated the tattooing mechanism, when the needle goes through the upper layer of the skin, depositing the biosensor in the dermis. The tattooed biosensor reacted with analytes and produced a color/intensity change. The vertical injections demonstrated the depth profile of the biosensor penetration into the skin.

 

Next Phase of Research

The results of our study show that this approach is promising and offers a novel direction for further biotechnology development. The next phase of this research will address the following challenges:

  1. Improve Sensor Performance: The range of colors and intensities of the current biosensors will be extended to enable higher-resolution readouts for quantitative measurements. The optimization of the sensitivity, selectivity, and detection range of the existing biosensors will accelerate their translation to the clinic.
  2. Optimize Safety and Biocompatibility: The safety profile of the biosensors will be characterized, beginning first with cytotoxicity assays and biocompatibility in vitro before progressing to in vivo animal studies to determine systemic biocompatibility, in terms of toxicity and interference with normal tissue and interstitial fluid function.
  3. Create Formulations for Long-Duration Implantation: Long-term in vivo research will be performed to establish the retention of the biosensors in the skin and to quantify biosensor diffusion in the skin tissue. One potential research direction is to conjugate the biosensors to polymeric microspheres to prevent diffusion into adjacent tissue layers.
  4. Investigate Tattoo Location Correspondence to Health Indication: The relationship between relative biosensor tattoo location and its correspondence to specific local versus whole-body health issues will be evaluated. Composition lag in interstitial fluid affects the ability to monitor particular health issues in real time.

Team: Katia Vega, Nan Jiang, Ali Yetisen, Nick Barry, Xin Liu, Pattie Maes, Joe Paradiso