A highly efficient biosensor based on MAPLE deposited hemoglobin on LPGs around phase matching turning point

•The MAPLE technique is applied to immobilize hemoglobin (Hb) upon LPGs.•The functionalized LPGs were used to selectively measure glucose concentration.•A total spectral shift of 13 nm was obtained for a concentration of 1.3 mmol/L.•We report reliable detection of glucose concentration down to 0.1 mmol/L.•The response is shown to be selectively caused by the glucose solutions alone. In this paper we report for a highly efficient sensor able to detect low-level glucose in saliva using ultra-sensitive long-period grating (LPG) fibre structure. Hemoglobin was directly immobilized on the structure by matrix-assisted pulsed-laser evaporation (MAPLE) method. Glucose binds to hemoglobin and the result is a glycated hemoglobin, the formation of which we detect. We demonstrate that the implemented technology allows for a clear relationship between glucose concentration and the spectral shift. As a result, a reliable detection of glucose concentration as low as 0.1 mmol/L is demonstrated.