Sensitive Leptospira DNA detection using tapered optical fiber sensor

Abstract

This paper presents the development of tapered optical fiber sensor to detect a specific Leptospira bacteria DNA. The bacteria causes Leptospirosis, a deadly disease but with common early flu-like symptoms. Optical single mode fiber (SMF) of 125 μm diameter is tapered to produce 12 μm waist diameter and 15 cm length. The novel DNA-based optical fiber sensor is functionalized by incubating the tapered region with sodium hydroxide (NaOH), (3-Aminopropyl) triethoxysilane and glutaraldehyde. Probe DNA is immobilized onto the tapered region and subsequently hybridized by its complementary DNA (cDNA). The transmission spectra of the DNA-based optical fiber sensor are measured in the 1500 to 1600 nm wavelength range. It is discovered that the shift of the wavelength in the SMF sensor is linearly proportional with the increase in the cDNA concentrations from 0.1 to 1.0 nM. The sensitivity of the sensor toward DNA is measured to be 1.2862 nm/nM and able to detect as low as 0.1 fM. The sensor indicates high specificity when only minimal shift is detected for non-cDNA testing. The developed sensor is able to distinguish between actual DNA of Leptospira serovars (Canicola and Copenhageni) against Clostridium difficile (control sample) at very low (femtomolar) target concentrations.

Advances in Fiber Optic DNA-Based Sensors: A Review

“…Tapered optical fiber sensor has also been used as an interferometer for detecting a specific ssDNA sequence of Leptospira bacteria [33]. These bacteria cause leptospirosis, a deadly disease but with common early flu-like symptoms.…”

Advanced Evanescent-Wave Optical Biosensors for the Detection of Nucleic Acids: An Analytic Perspective

“…Amino-silane surfaces can be also activated with 1,4-phenylenediisothiocyanate (PDITC), which provide isocyanate groups that can be reactive either to NH-DNA probes (Hu et al, 2015), yielding thiourea bonds, or to SH-DNA probes (Huertas et al, 2016b), forming thiocarbamate bonds. However, the most used homobifunctional crosslinker is glutaraldehyde, which forms a surface with aldehyde groups that lets the formation of imines by their covalent reaction with amine groups (Zainuddin et al, 2018). The fact that homobifunctional crosslinkers carry two identical chemical groups can cause undesired side effects such crosslinking between surface groups or biorecognition elements, which can actually inhibit the functionalization process.…”

Optical Fiber Based Mach-Zehnder Interferometer for APES Detection

“…Unsuitable amounts and concentrations often lead to failure of the experiments. Usually, in APES-based fiber-optic sensing experiments, the APES concentrations mostly range from 1% to 2%, and the immersion time ranges from 45 min to 2 h [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Therefore, it is valuable to determine suitable APES amounts and concentrations for the fabrication of optical fibers coated with well-proportioned APES films.…”