Highly Fluorescent Polycaprolactones with Tunable Light Emission Wavelengths across Visible to NIR Spectral Window

Polycaprolactone (PCL) has been widely used in biomedical applications such as tissue engineering due to its promising biodegradability, biocompatibility, and mechanical processability. However, commercially available PCL without any fluorescence does not meet the increasing demand in biomedical applications, for example, to monitor noninvasively the fate of implanted scaffolds in tissue engineering. To that end, exploration of new fluorescent PCL polymers plays an essential role in tracking their degradation under physiological conditions and distinguishing PCL scaffolds at the interface with biological systems such as cells and tissues. Herein, this study reports a series of tailor‐made fluorescent PCL polymers with various light emission wavelengths ranging from visible to near‐infrared (NIR) region in solid states. These fluorescent PCL polymers are amenable to be processed into nanofibers using electrospinning, as well as waterborne nanoparticle ink for macroscale stamping, brush writing, and microcontact printing. Finally, the application of the NIR fluorescent PCL for in vitro imaging and monitoring of scaffold degradation is demonstrated.