An optical microfiber interferometric biosensor for the low concentration detection of sequence-specific deoxyribonucleic acid (DNA) based on signal amplification technology via oligonucleotides linked to gold nanoparticles (Au-NPs) is proposed and experimentally analyzed. The sensor uses a "sandwich" detection strategy, in which capture probe DNA (DNA-c) is immobilized on the surface of the optical microfiber interferometer, the reporter probe DNA (DNA-r) is immobilized on the surface of Au-NPs, and the DNA-c and DNA-r are hybridized to the target probe DNA (DNA-t) in a sandwich arrangement. The dynamic detection of the DNA-t was found to range from 1.0×10 M to 1.0×10 M, and the limit of detection (LOD) concentration was 1.32 fM. This sensor exhibited not only a low LOD but also excellent selectivity against mismatched DNA-t, and it can be further developed for application in various sensing platforms.
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http://dx.doi.org/10.1364/OE.424878 | DOI Listing |
Commun Eng
December 2024
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, China.
Rapid and accurate determination of target proteins in cells provide essential diagnostic information for early detection of diseases, evaluation of drug responses, and the study of pathophysiological mechanisms. Traditional Western blotting method has been used for the determination, but it is complex, time-consuming, and semi-quantitative. Here, a tapered seven-core fiber (TSCF) biosensor was designed and fabricated.
View Article and Find Full Text PDFSmall Methods
December 2024
State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
Measurement of masses of microscale objects or weak force with ultrahigh sensitivity (down to nanogram/piconewton level) and compact configuration is highly desired for fundamental research and applications in various disciplines. Here, by using freestanding gold flakes with high reflectivity (≈98% at 980 nm) as the sample tray and silica microfibers with extremely low spring constant (≈0.05 mN m) as the cantilever beams, miniature capacitive balances are reported with piconewton-level detection limit (picobalances) and reliable radiation force-based calibration.
View Article and Find Full Text PDFThis paper proposes a novel seawater temperature sensor, to the best of our knowledge, that utilizes an optical microfiber coupler combined with a reflective silver mirror (OMCM). The sensor's sensitivity and durability are enhanced by encapsulating it in polydimethylsiloxane (PDMS). Additionally, a specially designed metal casing prevents the OMCM from responding to pressure, thus avoiding the challenge of multi-parameter demodulation and increasing its adaptability to harsh environments.
View Article and Find Full Text PDFImparting information on a light wave by signal modulation is fundamental for all forms of optical sensors. Here, we use a microfiber coupled whispering-gallery microcavity as a feedback element and experimentally demonstrate the intensity modulation on a fiber laser based on dissipative acousto-optic interaction where the acoustic wave modulates the coupling strength of suspended microfiber and microcavity, and accordingly modulates the decay rate of laser cavity. As high as 35% modulation depth is realized and the laser is then explored for the sensitive detection of an acoustic wave in air and a noise equivalent pressure of less than 0.
View Article and Find Full Text PDFOcean exploration-oriented temperature and salinity (TS) sensor based on bend-insensitive microfiber Mach-Zehnder interferometer (MMZI) is proposed and demonstrated in a marine environment. To solve the demodulation problem induced by the narrow waveband of the spectrometer used in the sea trial, a MMZI sensor is calibrated and demodulated by machine learning method. Results show that even if the wavelength range used in demodulation is as small as tens of nanometers, a relatively accurate demodulation can still be achieved.
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