Researchers at École Polytechnique de Montréal (Montréal, QC, Canada) have developed a microstructured optical fiber from biodegradable and water-soluble materials that could ultimately be used for applications such as laser-power delivery to biological tissue and controlled release of pharmaceuticals. To the authors’ knowledge, this is the first biocompatible, microfluidic fiber that incorporates optical sensing and medical-treatment functionalities.

A fiber preform was fabricated from two cellulose butyrate tubes (refractive index 1.475) with two different diameters. The space between the tubes was filled with a hydroxypropyl cellulose powder of lower index (1.337) to act as an inner cladding. In the drawing process, the air hole of the inner tube could be left open (for drug delivery or fluorescent-particle placement to enhance fluorescence microscopy) or collapsed (for laser delivery). The operating wavelength of between 700 and 1100 nm is within the window of available medical lasers; the fiber has a loss of 1 to 2 dB/cm. Contact Maksim Skorobogatiy at maksim.skorobogatiy@polymtl.ca.