Sensitive detection of Vitamin C using etched SMS based LSPR biosensor

Ascorbic acid, genreally known as Vitamin 'C', is a nutrient, which is responsible for numerous biological functions like collagen formation, iron absorption, growth and repair of cells, tissues, bones, cartilages, teeth etc. It plays a promising role in providing a healthy immunity against bacterial and viral infections. It also helps in making several chemical messenger and hormones, thus playing importance in the nervopus system of body. Thus, ascorbic acid is a biomarker for the detection of various malfunctionings of the body like weakened immunity, scurvy, cardiovascular diseases, Alzheimer's and Parkinson's disease. In this work, a straightforward and effectual sensor model is proposed to detect the presence of ascorbic acid samples found in human body. Etched single mode fiber-multimode fiber-single mode fiber (E-SMS) is used for developing the sensor with the application of localized surface plasmon resonance (LSPR) phenomenon. For achieving LSPR and better sensitivity, the E-SMS are coated with gold nanoparticles (AuNPs). The different concentration of ascorbic acid solution alters the refractive index and the spectrum thus recorded and evaluated. The experimental results shows that the proposed E-SMS-based LSPR biosensors can detect the presence of ascorbic acid in human body and thus have significant application in the field of biosensing.