Publications

@article{Wu2022-ko,

title = {Long period grating Mach-Zehnder interferometer based 

 immunosensor with temperature and bulk refractive index 

 compensation},

author = {Peizhou Wu and Liangliang Liu and Stephen P Morgan and Ricardo Correia and Serhiy Korposh},

year  = {2022},

date = {2022-11-01},

journal = {Biosensors (Basel)},

volume = {12},

number = {12},

pages = {1099},

publisher = {MDPI AG},

abstract = {A long period grating Mach-Zehnder interferometer (LPGMZI) that 

 consists of two identical long period gratings (LPGs) in a 

 single fibre was developed to measure immunoglobulin M (IgM). 

 The measured spectrum has fringes due to the interference 

 between the core mode and cladding mode. This immunosensor 

 inherits the advantages of an LPG and has the potential to 

 compensate for unwanted signal changes due to bulk refractive 

 index (RI) and temperature fluctuations by analysing 

 interference fringes and their envelope. The external RI was 

 measured from 1.3384 to 1.3670 in two different cases: (i) only 

 the connecting section between the two LPGs is immersed or (ii) 

 the whole LPGMZI is immersed. The fringes shift with an external 

 RI in both scenarios, whereas the envelope stays still in case 

 (i) or shifts at the same rate as the fringes in case (ii). The 

 LPGMZI was also characterised at different temperatures between 

 25 °C and 30 °C by placing the whole LPGMZI in a water bath. The 

 fringes and envelope shift at the same rate with temperature. 

 The LPGMZI platform was then used to create an IgM immunosensor. 

 The connecting section between the two LPGs was functionalised 

 with anti-IgM and immersed into solutions with IgM 

 concentrations from 20 μg/mL to 320 μg/mL. The fringes 

 shift with IgM concentration and the envelope remains static. 

 The results from this work show that LPGMZI has the potential to 

 compensate for the temperature and bulk RI fluctuations and 

 perform as a portable biosensor platform.},

keywords = {biosensor, bulk refractive   index, IgM, long period grating, Mach-Zehnder interferometer},

pubstate = {published},

tppubtype = {article}

}