Probing into the Skin’s Abyss

DermalAbyss was an early-stage, proof-of-concept research project, which has now ended. The below post, which was written in 2017, has been preserved for archival purposes. There are no plans to develop DermalAbyss as a product or to pursue clinical trials. 

Our launch of the DermalAbyss project was met with an unexpected level of interest and engagement from the public. We received an overwhelming number of inquiries regarding the status of our work and future research directions. We discuss the most common questions about the project through this blog post. 

What is DermalAbyss?

DermalAbyss was a proof-of-concept study.  Traditional tattoo inks are replaced with biosensors whose colors or fluorescent intensity change in response to variations in the concentrations of biomarkers in interstitial fluid. Biosensors are injected within the skin to explore the possibilities of tattoo-based skin interfaces and medical diagnostics. 

Please note: this research is at an initial research stage and is not available for clinical use. Challenges such as robustness, biocompatibility, permanence, and reversibility must be addressed before animal or human subject trials. 

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. 

The concept of utilizing biosensing tattoos offers an attractive alternative for health monitoringin vivofor 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 toin 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-termin 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.

We are so grateful for the attention and interest this project has received, both from the media and from people interested in the potential health benefits of a market-ready project. We hope that as this work matures, we can bring this biotechnology closer to the hands of doctors, patients, tattoo artists, and enthusiasts alike. If you’d like to stay tuned to our progress, please follow the Media Lab on Twitter, Facebook, and Instagram, and look for new research updates on the Media Lab website.

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