Experimental demonstration of protein sensing using hollow-core tube lattice fibers (Conference Presentation)

Abstract

Photonic Crystal Fibers represent a good platform for the development of sensitive and cheap sensors for the detection of protein and DNA sequence. The holes running along the fiber allows the infiltration of biological substances and for biological layers to attach on the air-dielectric interfaces. In addition, the presence of a hollow core can further increase the infiltration feasibility and the sensor sensitivity. Recently, the possibility in using hollow core tube lattice fibers (HC-TLFs) for label-free DNA detection have been numerically investigated. The sensing is based on the waveguiding mechanism, that is inhibited-coupling which makes the HC-TLF transmission properties particularly sensitive to the thickness of the glass struts composing the microstructured cladding of those fibers. The molecular interactions between the surface of the glass and the target to be detected results in a generation of a biological layer which modifies the strut thickness and thus the fiber transmission properties. The aim of the present work is to experimentally demonstrate that HC-TLF can be successfully used as bio sensor for proteins. After a functionalization of the silica surface through a solution of aptes, a layer of biotin was deposited on inner surfaces of the fiber. The fiber was than infiltrated with a solution containing streptavidin and an additional bio-layer is deposited on the surfaces. The experimental results demonstrated a red shift of the entire fiber transmission spectrum of about 7 nm corresponding to an additional bio-layer with thickness of 6.45 nm which is fully compatible with the size of streptavidin molecules of about 6nm.