title: Long period fiber grating based sensor for the detection of triacylglycerides.
abstract: In this paper, stable, label free enzyme based sensor using long period fiber grating (LPG) is described for the detection of triacylglycerides. A stable covalent binding technique for lipase enzyme immobilization on an optical fiber is reported. An active and stable attachment of the functional group of the enzyme on the fiber surface is achieved using this method. Enzyme immobilization is confirmed by Scanning Electron Microscopy (SEM) and Raman Spectroscopy. The stability is confirmed by lipase p-nitrophenyl palmitate (PNP) assay. In contrast to widely used amperometric based biosensor, where a number of enzymes are required, only one enzyme, namely, lipase is required in our sensor. The sensor shows optimum response within one minute at a temperature of 37°C and pH of 7.4. The sensor is based on the shift in resonance wavelength of the LPG transmission spectrum due to the interaction of triacylglycerides with the enzyme. The biosensor is highly specific towards triacylglycerides and is unaffected by the presence of many other interfering substances in serum. Interaction between the bio-molecules and the long period grating surface is also modeled theoretically using a four layer model for the LPG fiber with the bio-recognition layer and the results obtained are consistent with experimentally obtained results. The sensor shows a high sensitivity of 0.5 nm/mM and a low detection limit of 17.71 mg/dl for the physiological range of triacylglycerides in human blood.
authors.affiliation: Department of Electronic Science, University of Delhi South Campus, New Delhi 110021, India. Electronic address: anjlibaliyan@gmail.com.
authors.forename: Anjli
authors.initials: A
authors.lastname: Baliyan
authors.affiliation: Department of Electronic Science, University of Delhi South Campus, New Delhi 110021, India. Electronic address: shivanisital18@gmail.com.
authors.forename: Shivani
authors.initials: S
authors.lastname: Sital
authors.affiliation: Central Scientific Instruments Organization, Sector (CSIR-CSIO)30 C, Chandigarh 160030, India. Electronic address: uktiwaricsio@yahoo.in.
authors.forename: Umesh
authors.initials: U
authors.lastname: Tiwari
authors.affiliation: Department of Microbiology, University of Delhi South Campus, New Delhi 110021, India. Electronic address: ranigupta15@yahoo.com.
authors.forename: Rani
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Department of Electronic Science, University of Delhi South Campus, New Delhi 110021, India. Electronic address: enakshi54@yahoo.co.in.
authors.forename: Enakshi K
authors.initials: EK
authors.lastname: Sharma
mesh_terms: D000215:Acylation; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D004867:Equipment Design; D005989:Glycerides / Q000097:blood* / Q000378:metabolism; D006801:Humans; D057230:Limit of Detection; D008049:Lipase / Q000737:chemistry / Q000378:metabolism; D055100:Optical Fibers
chemical_list: D004800:Enzymes, Immobilized; D005989:Glycerides; D008049:Lipase
keywords: Biosensing; Covalent binding; Lipase; Long period fiber grating; Triacylglycerides