Fabrication of a light-emitting shape memory polymeric web containing indocyanine green

Dye-containing polymers are highly desired for a number of commercially and medically relevant applications, such as sensors, medical devices, and drug delivery. In particular, dyes that emit light in the NIR region of the electromagnetic spectrum are of great interest due to the window of transparency for mammalian soft tissue in this range. While the incorporation of dyes into polymeric hosts by diffusion is a method that has been widely used, this approach is problematic in that it lacks uniformity and control over the incorporation. Here, we sought to develop NIR-emitting polymeric materials with high fluorescence intensity, addressing the problem of uniformity by incorporating the dye in a polymer host using dissolution in a mutual solvent and subsequent electrospinning into a fibrous web. This web could be prepared as a free-standing film, a coating or, as we will show, a shrink-wrap medical device label. The primary findings of this study were that an optimal concentration of dye in the polymer host exists, that the fluorescence intensity for fibrous webs greatly exceed that of comparable cast films, and that the dye-containing webs feature water-triggered contraction of use for application to medical devices, such as feeding tubes or catheters.