scholarly journals Liquid crystal-amplified optofluidic biosensor for ultra-highly sensitive and stable protein assay

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Ziyihui Wang ◽  
Yize Liu ◽  
Chaoyang Gong ◽  
Zhiyi Yuan ◽  
Liang Shen ◽  
...  
Keyword(s):  
Internal Surface ◽  
High Sensitivity ◽  
Optical Microscope ◽  
Wavelength Shift ◽  
Biomolecular Detection ◽  
Alignment Layer ◽  
Protein Assay ◽  
Sensing Platform ◽  
Protein Molecules ◽  
Protein Assays

AbstractProtein assays show great importance in medical research and disease diagnoses. Liquid crystals (LCs), as a branch of sensitive materials, offer promising applicability in the field of biosensing. Herein, we developed an ultrasensitive biosensor for the detection of low-concentration protein molecules, employing LC-amplified optofluidic resonators. In this design, the orientation of LCs was disturbed by immobilized protein molecules through the reduction of the vertical anchoring force from the alignment layer. A biosensing platform based on the whispering-gallery mode (WGM) from the LC-amplified optofluidic resonator was developed and explored, in which the spectral wavelength shift was monitored as the sensing parameter. The microbubble structure provided a stable and reliable WGM resonator with a high Q factor for LCs. It is demonstrated that the wall thickness of the microbubble played a key role in enhancing the sensitivity of the LC-amplified WGM microcavity. It is also found that protein molecules coated on the internal surface of microbubble led to their interactions with laser beams and the orientation transition of LCs. Both effects amplified the target information and triggered a sensitive wavelength shift in WGM spectra. A detection limit of 1 fM for bovine serum albumin (BSA) was achieved to demonstrate the high-sensitivity of our sensing platform in protein assays. Compared to the detection using a conventional polarized optical microscope (POM), the sensitivity was improved by seven orders of magnitude. Furthermore, multiple types of proteins and specific biosensing were also investigated to verify the potential of LC-amplified optofluidic resonators in the biomolecular detection. Our studies indicate that LC-amplified optofluidic resonators offer a new solution for the ultrasensitive real-time biosensing and the characterization of biomolecular interactions.

scholarly journals Sensitive and In Situ Hemoglobin Detection Based on a Graphene Oxide Functionalized Microfiber

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2461
Author(s):  
Fang Fang ◽  
Yanpeng Li ◽  
Liuyang Yang ◽  
Liangye Li ◽  
Zhijun Yan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Detection Limit ◽  
Light Field ◽  
Low Cost ◽  
High Sensitivity ◽  
Optical Microscope ◽  
Wavelength Shift ◽  
Compact Structure ◽  
Blood Diseases ◽  
Evanescent Light

The determination of hemoglobin (Hb) level is indispensable in the pathological study of many blood diseases. Graphene oxide (GO), with its excellent optical properties and great biocompatibility, has attracted significant attention and been widely utilized in biochemical detection. Here, we report an ultrasensitive Hb sensor based on a graphene oxide (GO)-coated microfiber. The GO was utilized as a linking layer deposited on the microfiber surface, which can provide an enhanced local evanescent light field and abundant bonding sites for Hb molecules. The optical microfiber with a compact structure and a strong evanescent light field served as the platform for biosensing. The surface morphology characterized by optical microscope, scanning electron microscope, and Raman spectroscopy offers detailed evidence for the success of GO deposition. The dynamic bonding between GO and target Hb molecules was monitored in real-time through an optical spectrum analyzer. An ultrahigh sensitivity of 6.02 nm/(mg/mL) with a detection limit of 0.17 μg/mL was achieved by tracking the resonant wavelength shift of spectra. It is important to highlight that the detection limit of GO-coated microfiber is 1–2 orders of magnitude lower than other reported fiber optic Hb sensors. Benefiting from high sensitivity, low cost, small size, and fast response, the proposed sensing microfiber coated with GO could be a competitive alternative in the diagnosis of blood diseases and a subject of further research in the medical field.

Core-shell Cu@C@ZIF-8 composite: a high-performance electrode material for electrochemical sensing of nitrite with high selectivity and sensitivity

2021 ◽  
Author(s):  
Feng Gao ◽  
Xiaolong Tu ◽  
Yongfang Yu ◽  
Yansha Gao ◽  
Jin Zou ◽  
...  
Keyword(s):  
High Performance ◽  
High Selectivity ◽  
Limit Of Detection ◽  
Metal Organic Framework ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Core Shell ◽  
Zeolitic Imidazolate Framework ◽  
Sensing Platform ◽  
The Difference

Abstract Herein, an efficient electrochemical sensing platform is proposed for selective and sensitive detection of nitrite on the basis of Cu@C@Zeolitic imidazolate framework-8 (Cu@C@ZIF-8) heterostructure. Core-shell Cu@C@ZIF-8 composite was synthesized by pyrolysis of Cu-metal-organic framework@ZIF-8 (Cu-MOF@ZIF-8) in Ar atmosphere on account of the difference of thermal stability between Cu-MOF and ZIF-8. For the sensing system of Cu@C@ZIF-8, ZIF-8 with proper pore size allows nitrite diffuse through the shell, while big molecules cannot, which ensures high selectivity of the sensor. On the other hand, Cu@C as electrocatalyst promotes the oxidation of nitrite, thereby resulting high sensitivity of the sensor. Accordingly, the Cu@C@ZIF-8 based sensor presents excellent performance for nitrite detection, which achieves a wide linear response range of 0.1 µM to 300.0 µM, and a low limit of detection (LOD) of 0.033 µM. In addition, the Cu@C@ZIF-8 sensor possesses excellent stability and reproducibility, and was employed to quantify nitrite in sausage samples with recoveries of 95.45-104.80%.

Broad-Spectrum Polymeric Nanoquencher as an Efficient Fluorescence Sensing Platform for Biomolecular Detection

ACS Sensors ◽  
2021 ◽  
Author(s):  
Xiao Dong ◽  
Sing Yee Ong ◽  
Changyu Zhang ◽  
Wenqiang Chen ◽  
Shubo Du ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Fluorescence Sensing ◽  
Biomolecular Detection ◽  
Sensing Platform

High sensitivity optical microscope for single molecule spectroscopy studies

2004 ◽  
Vol 75 (8) ◽  
pp. 2746-2751 ◽  
Author(s):  
Gabriele Malengo ◽  
Roberto Milani ◽  
Fabio Cannone ◽  
Silke Krol ◽  
Alberto Diaspro ◽  
...  
Keyword(s):  
Single Molecule ◽  
High Sensitivity ◽  
Optical Microscope ◽  
Single Molecule Spectroscopy ◽  
Spectroscopy Studies

Rheo-Optics Studies in the Development of Hybrid Liquid Crystalline Based Mwir Polarizers

1999 ◽  
Vol 559 ◽  
Author(s):  
P.T. Mather ◽  
W. Barnes ◽  
P.J. Hood ◽  
T.J. Bunning
Keyword(s):  
Liquid Crystalline ◽  
Flow Behavior ◽  
Optical Microscope ◽  
Processing Technique ◽  
Strain Rates ◽  
Alignment Layer ◽  
Small Pitch ◽  
Wide Range ◽  
Measured Polarization ◽  
Free Films

ABSTRACTWe present here a rheo-optical study of the flow behavior of two cholesteric liquid crystals, one with a large pitch and one with a small pitch. The large pitch compound has been investigated as a possible fixed wavelength polarizer in the mid-wavelength infra-red region (3-5 micron). The investigation of these compounds is driven by their low melt viscosity and ability to vitrify order, and thus functionality, into films with a wide range of thickness. In our attempts to obtain consistent thin films with reproducible contrast ratios, we explored the defect textures of both compounds under a polarizing optical microscope. These materials were sheared at various strain rates and at various temperatures in an attempt to determine the best processing window for defect free films. The pitch lengths of the two materials investigated were 160 and 1330 nm. The flow behavior of the large pitch material resembles a pure nematic with defect refinement taking place under flow. The short pitch material exhibited the typical Grandjean oily streaks upon shearing followed by coarsening. Observations made during this rheological study were used to identify a processing technique for the large pitch materials. Upon application of a conventional buffed alignment layer, films with consistent quality were routinely made. The measured polarization contrast of >70:1 exceeds the values obtained from state-of-the art commercial polarizers in this wavelength regime.

scholarly journals Comparison of Triangular Silver Nanoprisms with Different Capping Agents and Structural Size for H2O2 Etching-Based Biosensors

NANO ◽  
2018 ◽  
Vol 13 (02) ◽  
pp. 1850022 ◽  
Author(s):  
Lishi Huang ◽  
Caihong Yuan ◽  
Wenli Chen ◽  
Fanshu Zeng ◽  
Hui Xu ◽  
...  
Keyword(s):  
Point Of Care ◽  
High Sensitivity ◽  
Wavelength Shift ◽  
Time Saving ◽  
Capping Agents ◽  
Silver Nanoprisms ◽  
Structural Size ◽  
Point Of Care Diagnostics ◽  
Citrate Capping ◽  
Capping Ligands

This study compared the susceptibility of different triangular silver nanoprisms (TSNPRs) towards the etching of hydrogen peroxide (H2O2), a catalytical product of glucose oxidase (GOx). The influence of capping agents and structural size have been explored towards the oxidation of silver nanoprisms. Results indicated that the etching of the TSNPRs was extremely effected by surface capping agents, in which citrate contributed a highest H2O2-sensitive effect in the absence of secondary capping ligands (e.g., glycerol and ethanol). Meanwhile, compared to bigger TSNPRs, smaller nanoprisms exhibited a different signal output of plasma resonance peak through intensity decrease rather than wavelength shift, making them more H2O2-etching susceptibile. In virtue of GOx etching-based system, TSNPRs with a small size and citrate capping were served as a substitute for big nanoprisms to sense glucose, offering a number of advantages such as high sensitivity, improved calibration, time-saving and extended detection ranges. Moreover, the small sized TSNPRs capping with citrate alone have been expected to be of great interest in the trace of GOx, providing an ultrahigh sensitive GOx etching-based analytical platform for point-of-care diagnostics towards other analytes (e.g., DNA, protein).

scholarly journals Multifunctional Textile Platform for Fiber Optic Wearable Temperature-Monitoring Application

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 866 ◽  
Author(s):  
Ziyang Xiang ◽  
Liuwei Wan ◽  
Zidan Gong ◽  
Zhuxin Zhou ◽  
Zhengyi Ma ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Temperature Sensor ◽  
High Sensitivity ◽  
Wavelength Shift ◽  
Heat Sources ◽  
Time Dynamic ◽  
Textile Sensor ◽  
Fbg Sensors ◽  
Comfort Parameters ◽  
Monitoring Application

Wearable sensing technologies have been developed rapidly in the last decades for physiological and biomechanical signal monitoring. Much attention has been paid to functions of wearable applications, but comfort parameters have been overlooked. This research presents a developed fabric temperature sensor by adopting fiber Bragg grating (FBG) sensors and processing via a textile platform. This FBG-based quasi-distributed sensing system demonstrated a sensitivity of 10.61 ± 0.08 pm/°C with high stability in various temperature environments. No obvious wavelength shift occurred under the curvatures varying from 0 to 50.48 m−1 and in different integration methods with textiles. The temperature distribution monitored by the developed textile sensor in a complex environment with multiple heat sources was deduced using MATLAB to present a real-time dynamic temperature distribution in the wearing environment. This novel fabric temperature sensor shows high sensitivity, stability, and usability with comfort textile properties that are of great potential in wearable applications.

scholarly journals Colorimetric Detection of Sulfide Anions via Redox-Modulated Surface Chemistry and Morphology of Au-Hg Nanorods

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaotian Zhu ◽  
Chang Liu ◽  
Jie Liu
Keyword(s):  
Surface Chemistry ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Localized Surface Plasmon ◽  
Wavelength Shift ◽  
Colorimetric Sensing ◽  
Leather Industry ◽  
Colorimetric Response ◽  
Sensitivity And Selectivity

A new colorimetric assay for the detection of sulfide anions with high sensitivity and selectivity is reported, utilizing Au-Hg alloy nanorods (Au-HgNRs) as probe. Au-HgNRs were prepared by modifying gold nanorods (AuNRs) with reducing agent and mercury ions. In an aqueous solution with sulfide anions, the formation of mercuric sulfide due to redox reaction between the amalgams and sulfide anions greatly changed the surface chemistry and morphology of the Au-HgNRs, leading to a red shift of the localized surface plasmon resonance (LSPR) absorption peak, accompanied by a change in colorimetric response. A good linear relationship was obtained between the LSPR peak wavelength shift and concentration of sulfide anion in the range of 1 × 10−5−1 × 10−4 mol/L. The selectivity of this method has been investigated by other anions. The colorimetric sensing system successfully detected sulfide in wastewater from leather industry.

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