  A fundamental issue in biomedical and environmental sciences is the
development of sensitive and robust sensors able to probe the analyte of
interest, under physiological and pathological conditions or in environmental
samples, and with very high spatial resolution. In this work, novel hybrid
organic fibers that can effectively report the analyte concentration within the
local microenvironment are reported. The nanostructured and flexible wires are
prepared by embedding fluorescent pH sensors based on
seminaphtho-rhodafluor-1-dextran conjugate. By adjusting capsule/polymer ratio
and spinning conditions, the diameter of the fibers and the alignment of the
reporting capsules are both tuned. The hybrid wires display excellent
stability, high sensitivity, as well as reversible response, and their
operation relies on effective diffusional kinetic coupling of the sensing
regions and the embedding polymer matrix. These devices are believed to be a
powerful new sensing platform for clinical diagnostics, bioassays and
environmental monitoring.
