Hollow core photonic crystal fiber as a reusable Raman biosensor.

We report that a single hollow core photonic crystal fiber (HC-PCF) can be used for repetitive characterization of multiple samples by Raman spectroscopy. This was achieved by integrating the HC-PCF to a differential pressure system that allowed effective filling, draining and re-filling of samples into a HC-PCF under identical optical conditions. Consequently, high-quality and reliable spectral data could be obtained which were suitable for multivariate analysis (partial least squares). With the present scheme, we were able to accurately predict different concentrations of heparin and adenosine in serum. Thus the detection scheme as presented here paves a path for the inclusion of HC-PCFs in point-of-care technologies and environmental monitoring where rapid sample characterization is of utmost importance.