Chitosan-Integrated Single-Mode Tapered Optical Fiber DENV II E Protein Sensor

This work reports the enhancement of a single-mode tapered optical fiber (TOF) sensor for Dengue virus (DENV) II E protein using chitosan. Chitosan, an organic nanomaterial with excellent biocompatibility and abundant binding sites, was deposited on TOF as an intermediate layer between the activated taper surface and the anti-DENV II E protein antibodies. The best DENV sensing performance was attained at chitosan thickness of 17.13 nm, which was attributed to the optimum balance between the auxiliary layer thickness and penetration depth of the evanescent field. An enhanced sensitivity value of 14.19 nm/nM was achieved compared to the sensitivity obtained by standard configuration sensor. A lower dissociation constant, K
_d
of 1.00×10
^-10
M was also acquired, which implies a higher affinity towards the targeted E protein. Findings from this work highlight the potential of organic nanomaterial such as chitosan for biosensor enhancement and further emphasize the capability of fiber optic sensors for detection of dengue virus as well as other antigens.