Optofluidic twin-core hollow fiber interferometer for label-free sensing of the streptavidin-biotin binding

Optical Fiber Optofluidic Bio‐Chemical Sensors: A Review

“…In recent years, with the rapid development of optofluidic technology, some specialty MOFs, including hollow twin-core optical fiber (HTCF), [45,46] hollow single-core fiber (HSCF), [47,48] side-hole fiber (SHF), [49,50] suspended-core fiber (SCF), [51,52] sidechannel PCF (SC-PCF), [53,54] and exposed-core fiber (ECF), [55][56][57] with unique advantages of rapid liquid filling and large overlap area between light and analytes, have attracted abundant attention in the field of OFOF biochemical sensing.…”

“…[45] After that, based on the HTCF, the research group prepared an in-fiber optofluidic MZI for the detection of biotin concentration. [46] In 2012, Yang et al designed and prepared the HSCF for the first time. [58] Later, based on the fiber, the author prepared some compact OFOF sensors for the detection of ascorbic acid concentration and nitrite concentration respectively.…”

“…So far, the existing methods for creating fluid access are as follows. First, fs laser and CO 2 laser are used to precisely drill holes on the surface of the fiber, [43,46] but this micromachining method is relatively complicated and requires expensive equipment. Second, the side-polishing technique is applied to polish a microport on the surface of the SMF.…”

“…Therefore, proteins can be bound to carboxyl groups (amino groups) of cross-linking agents or other conjugated molecules through amide bonds. For example, the carboxyl of biotin can be covalently cross-linked with the amino of polypropylene amine hydrochloride to form an amide bond; [57] similarly, the carboxyl of the antibody can be covalently bound to the amino of 3-aminopropyltrimethoxysilane; [95] the amino of streptavidin can be linked to the crosslinker 4-Maleimidobutyric acid N-hydroxysuccinimide ester and epoxy group of 3-glycidoxypropyltrimethoxysilan; [46,79] the amino of anti-cTnI can be bind to the carboxyl of PAA activated by ethalcarbodimide hydrochloride (EDC)/N-Hydroxysuccinimide (NHS). [84] In the process of self-assembly, appropriate crosslinking agents or conjugated molecules should be selected according to the receptor molecules to be bound to the optical fiber.…”

“…OFOF bio-chemical sensors based on MZI have been investigated for several decades, and various types of structures have been reported, including microcavities, [215,216] microfibers, [217][218][219][220][221] and other types of fibers. Other types of fibers include thin-core fiber, [222] TCF, [223] HTCF, [45,46] dual sidehole fiber (DSHF). [49] These MZIs have been used to measure RI, gas pressure, DNA, protein concentration, glucose concentration, and vitamin C concentration, etc.…”