Technology Development

The Sencil resembles the configuration of chronically implanted artificial hair used for cosmetic purposes. Such hairs consist of filaments of synthetic polymer that can be injected into the scalp, where they form an epithelial interface that is stable for months at least. Likewise, the Sencil is implantable underneath the skin into a well-vascularized subcutaneous space such as the scalp. A single optical fiber makes up the “shaft” of the hair, and the sensing system serves as the “follicle”.

One potential analyte of interest is glucose, which is measured to adjust insulin dosage for diabetes, and which represents the largest segment of commercial sensor research. Other analytes that seem particularly suitable for the technology include hormones related to fertility, premature delivery and other late-term complications of pregnancy such as eclampsia. The technology could be applied to assay tissue levels of drugs that have narrow margins between effective and dangerous levels, such as cytotoxic chemotherapeutics and anticoagulants.

The Sencil:

  • The fluorescence resonance energy transfer (FRET) technique was selected bcause it provides:
    • A satisfactory signal-to-noise ratio
    • Sufficient precision and accuracy to yield clinically useful information
    • A method relatively insensitive to the anticipated gradual biodegradation of the biosensor element
    • Allows the development of competitive binding assays
  • Silica multimode optical fibers were selected on the basis of their optical properties, biocompatibility and toughness
  • Polyethylene glycol was selected as the matrix component for the Biosensor Element
  • Mild etching of the optical fiber improved adhesion between the optical fiber and the Biosensor matrix, as well as the epithelial cell layers

Portable Photonic Analyzer:

The portable photonic analyzer (Reader) will be constructed from “off the shelf” components that can be programmed to support a wide range of Sencils for different analytes.


Alfred Mann Institute University of Southern California