Fluorescent tracer agent-based monitoring systems are built upon two core technology pillars.

Together these components designed to enable clinically relevant measurement and monitoring of organ function in real-time at the point of care.

Biocompatibility – Biocompatible fluorescent agents have the quality of not having toxic or injurious effects on biological systems.
Hydrophilic – This is the characteristic of having a tendency to mix with or dissolve in water.
Negligible Protein Binding – The quality of not attaching to proteins within the body is an important characteristic.
Negligible Metabolism – This is measured by quantifying the amount of the agent that is excreted intact.
Neglibible Photobleaching – It is important to engineer against any potential photochemical alteration of a fluorophore molecule that would permanently hinder its ability to fluoresce.

Physiologic pH Formulation – The pH of a pharmaceutical solution cannot be too acidic or too basic. The further away one gets from physiological pH (7.4), the greater the irritation. Delivery at physiologic pH is optimal.
Small Dose – The need for only a small amount of fluorescent agent in the body has positive implications for the detection end of transdermal measurement systems. In addition, small dose requirements may enable alternative routes of administration for the fluorescent tracer agents.
Chemical Stability – The tendency of fluorescent tracer agents to resist change or decomposition due to internal reaction, or due to the action of air, heat, light, pressure, etc. helps to ensure the desired engineered properties of a fluorescent agent remain in place so that the product can serve its intended purpose in transdermal measurement systems.

Solubility – Fluorescent tracer agents that are highly soluble tend to be easier to formulate, handle and use.
Photo Stability – To be photostable refers to the tendency of a fluorescent tracer agent to be stable in the presence of light. Highly photo stable compounds are the goal so as to facilitate storage, handling and use in transdermal measurement systems.
Stokes Shift – The Stokes shift is the difference between the emission light wavelength (color of light at which the fluorescent agent glows) and the incident light wavelength (color of light which is shined on the fluorescent agent to make it glow). Fluorescent tracer agents with a large Stokes Shift are desirable and favor robust and cost-effective biosensor detection systems.

One of the long-standing challenges in skin imaging is to develop quantitative methods for characterizing anatomy and physiology in different skin structures.
- Journal of Biomedical Optics, In vivo measurements of cutaneous melanin across spatial scales: using multiphoton microscopy and spatial frequency domain spectroscopy, June 2015