Immunoassays Using Optical-Fiber Sensor with All-Directional Chemiluminescent Collection

Abstract

While chemiluminescent optical-fiber sensors present essential advantages for immunoassays of biomarkers, an inherent limitation hampering their detection sensitivity is the low collection efficiency of chemiluminescent emission induced by samples, owing to the microspatial scale of an optical fiber for transmission of light via total internal reflection. Here we present a robust approach to overcome this limitation, based on a uniquely designed all-optical chemiluminescent collection vial (CC vial) by using a concave mirror and a coaxial tubular mirror as its bottom and wall, respectively. Using cardiac troponin I (cTnI), a highly specific but low abundance cardiac biomarker, as the test sample, we show that accurate assays can be achieved in a wide linear range of 1–80000 pg/mL. The limit of detection is as low as 0.31 pg/mL, which is about 2 orders of magnitude lower than that obtained by a normal chemiluminescent optical fiber sensor. The method is successfully applied for determination of cTnI in real human serum samples with good accuracy and repeatability. Our study shows that the method can perform an all-directional collection of the chemiluminescent emission, thus, greatly enhancing the collection efficiency and improving the sensitivity of the immunoassays. It is also worth mentioning that the proposed strategy requires neither complex equipment nor additional chemicals, making it a cost-effective and universal approach for ultrasensitive detection of trace biomarkers.

Versatile Biosensing Toolkit Using an Electronic Particle Counter

“…Current strategies for biosensor development mainly include optical, − electrical, ,, and magnetic approaches, − among which electrical biosensors stand out due to their accessibility, high sensitivity, and low cost. The electrical resistance-based particle counter (ERPC) is a scientific measuring instrument that uses the Coulter counter principle to convert each particle into a pulse signal proportional to its volume. − The amplitude and count of this pulse sequence can be used to calculate the particle size and the number distribution.…”

Recent Advances in Cardiovascular Disease Biosensors and Monitoring Technologies

“…Most importantly, light-based sensors allow the acquisition of physiological signals from a deep tissue environment. − Optical fiber biosensors capture the presence of an analyte on a fiber surface by detecting its wavelength and transmitting it to a digital signal for processing . Nie et al resolved the limitations of traditional chemiluminescent optical fiber sensors (COFS) and developed a robust system to quantify the level of cTnI with a broad detection range of 1–80000 pg/mL and LOD of 0.31 pg/mL (Figure a). In traditional COFS, an optical fiber is used to immobilize the analyte based on a biorecognition molecule.…”

Prefab Hollow Glass Microsphere-Based Immunosensor with Liquid Crystal Sensitization for Acute Myocardial Infarction Biomarker Detection

“…In addition to traditional immunoassays, the convenient use of biosensors to assess the cTn concentration has become one of the most expectant diagnostic tools for AMI prediction [ 10 ]. At present, electrochemical (ELC) [ 11 ], field-effect transistor (FET) [ 12 ], lateral flow immunoassay (LFIA) [ 13 ], and optical fiber [ 14 , 15 , 16 , 17 , 18 ] biosensors are attractive for point-of-care testing (POCT) [ 19 ], which facilitate a whole new horizon for possible treatment and prevention of cardiovascular diseases. With the development of materials and manufacturing technologies, optical fiber biosensors in particular have been exploited for cTn assays in recent years owing to their fiber waveguide structure and biocompatible silica materials.…”

“…Ran, et al reported an evanescent field biosensor based on harmonic resonances microfiber grating [ 17 ], and the impact of the thermal noise could be reduced by the harmonic resonances with different responses. In addition, the chemiluminescent optical fiber cTnI biosensor with a unique all-directional chemiluminescent collection vial for sensitivity improvement was also reported [ 18 ], and its LOD is as low as 0.31 pg/mL. Although some optical fiber biosensors have been explored for cTnI detection, the sensing elements of fiber sensors with lengths of several millimeters to centimeters need to be immersed in the samples to be tested, and the consumptions of samples and reagents still cannot meet the requirements of microanalysis.…”