Nanoscale diameter control of sensory polydiacetylene nanoparticles on microfluidic chip for enhanced fluorescence signal

2016 ◽  
Vol 230 ◽  
pp. 623-629 ◽  
Author(s):  
Sunghoon Baek ◽  
Simon Song ◽  
Joosub Lee ◽  
Jong-Man Kim
2020 ◽  
Vol 20 (5) ◽  
pp. 3195-3200 ◽  
Author(s):  
Jian Wu ◽  
Yongjun Du ◽  
Chunyan Wang ◽  
Tao Chen

Surface-enhanced fluorescence detection has large potential for detecting many chemical and biological trace analytes. This paper presents a novel method for preparing silver nanomaterials in microfluidic chip channels for the surface-enhanced fluorescence detection of fluorescent dye (SYBR Green I) molecules. Microfluidic chip channels were fabricated by a 248-nm excimer laser. Silver nanoparticles (Ag-NPs) were prepared inside the microfluidic chip channels by directly heating the silver precursor solution. The influence of different temperatures on the sizes of the silver nanoparticles was studied. Then, the surface-enhanced fluorescence technology based on the microfluidic system was used to detect the fluorescent dye molecules. As a result, the fluorescence signal of the fluorescent dye molecules was significantly enhanced by the silver nanoparticles. In addition, the effect of particle size on the fluorescence signal was studied. This simple and fast method is suitable for a fluorescent PCR (polymerase chain reaction) system and has good application prospects for detecting harmful microorganisms in a spacecraft.


Nanophotonics ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 472-490 ◽  
Author(s):  
Jun Dong ◽  
Zhenglong Zhang ◽  
Hairong Zheng ◽  
Mentao Sun

AbstractThe optically generated collective electron density waves on metal–dielectric boundaries known as surface plasmons have been of great scientific interest since their discovery. Being electromagnetic waves on gold or silver nanoparticle’s surface, localised surface plasmons (LSP) can strongly enhance the electromagnetic field. These strong electromagnetic fields near the metal surfaces have been used in various applications like surface enhanced spectroscopy (SES), plasmonic lithography, plasmonic trapping of particles, and plasmonic catalysis. Resonant coupling of LSPs to fluorophore can strongly enhance the emission intensity, the angular distribution, and the polarisation of the emitted radiation and even the speed of radiative decay, which is so-called plasmon enhanced fluorescence (PEF). As a result, more and more reports on surface-enhanced fluorescence have appeared, such as SPASER-s, plasmon assisted lasing, single molecule fluorescence measurements, surface plasmoncoupled emission (SPCE) in biological sensing, optical orbit designs etc. In this review, we focus on recent advanced reports on plasmon-enhanced fluorescence (PEF). First, the mechanism of PEF and early results of enhanced fluorescence observed by metal nanostructure will be introduced. Then, the enhanced substrates, including periodical and nonperiodical nanostructure, will be discussed and the most important factor of the spacer between molecule and surface and wavelength dependence on PEF is demonstrated. Finally, the recent progress of tipenhanced fluorescence and PEF from the rare-earth doped up-conversion (UC) and down-conversion (DC) nanoparticles (NPs) are also commented upon. This review provides an introduction to fundamentals of PEF, illustrates the current progress in the design of metallic nanostructures for efficient fluorescence signal amplification that utilises propagating and localised surface plasmons.


Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4132
Author(s):  
Jung Ho Kim ◽  
Seokjoon Kim ◽  
Sung Hyun Hwang ◽  
Tae Hwi Yoon ◽  
Jung Soo Park ◽  
...  

The consumption of water and food contaminated by pathogens is a major cause of numerous diseases and deaths globally. To control pathogen contamination and reduce the risk of illness, a system is required that can quickly detect and monitor target pathogens. We developed a simple and reproducible strategy, termed three-way junction (3WJ)-induced transcription amplification, to detect target nucleic acids by rationally combining 3WJ-induced isothermal amplification with a light-up RNA aptamer. In principle, the presence of the target nucleic acid generates a large number of light-up RNA aptamers (Spinach aptamers) through strand displacement and transcription amplification for 2 h at 37 °C. The resulting Spinach RNA aptamers specifically bind to fluorogens such as 3,5-difluoro-4-hydroxybenzylidene imidazolinone and emit a highly enhanced fluorescence signal, which is clearly distinguished from the signal emitted in the absence of the target nucleic acid. With the proposed strategy, concentrations of target nucleic acids selected from the genome of Salmonellaenterica serovar Typhi (S. Typhi) were quantitatively determined with high selectivity. In addition, the practical applicability of the method was demonstrated by performing spike-and-recovery experiments with S. Typhi in human serum.


2009 ◽  
Vol 17 (8) ◽  
pp. 6421 ◽  
Author(s):  
Christoph J. Engelbrecht ◽  
Werner Göbel ◽  
Fritjof Helmchen

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1749 ◽  
Author(s):  
Mohsin Ali Badshah ◽  
Na Yoon Koh ◽  
Abdul Wasy Zia ◽  
Naseem Abbas ◽  
Zahra Zahra ◽  
...  

Metal-enhanced fluorescence (MEF) is a unique phenomenon of surface plasmons, where light interacts with the metallic nanostructures and produces electromagnetic fields to enhance the sensitivity of fluorescence-based detection. In particular, this enhancement in sensing capacity is of importance to many research areas, including medical diagnostics, forensic science, and biotechnology. The article covers the basic mechanism of MEF and recent developments in plasmonic nanostructures fabrication for efficient fluorescence signal enhancement that are critically reviewed. The implications of current fluorescence-based technologies for biosensors are summarized, which are in practice to detect different analytes relevant to food control, medical diagnostics, and forensic science. Furthermore, characteristics of existing fabrication methods have been compared on the basis of their resolution, design flexibility, and throughput. The future projections emphasize exploring the potential of non-conventional materials and hybrid fabrication techniques to further enhance the sensitivity of MEF-based biosensors.


Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 48
Author(s):  
Jun Kim ◽  
Naseem Abbas ◽  
Seongmin Lee ◽  
Jeongwoo Yeom ◽  
Md Ali Asgar ◽  
...  

A simple and cost-effective method is proposed herein for a plasmonic nanoantenna array (PNAA) for the fabrication of metal-enhanced fluorescence (MEF) substrates in which fluorophores interact with the enhanced electromagnetic field generated by a localized surface plasmon to provide a higher fluorescence signal. The PNAA is fabricated by the deposition of a silver (Ag) layer on an ultraviolet (UV) nanoimprinted nanodot array with a pitch of 400 nm, diameter of 200 nm, and height of 100 nm. During deposition, raised Ag nanodisks and a lower Ag layer are, respectively, formed on the top and bottom of the imprinted nanodot array, and the gap between these Ag layers acts as a plasmonic nanoantenna. Since the thickness of the gap within the PNAA is influenced by the thickness of Ag deposition, the effects of the latter upon the geometrical properties of the fabricated PNAA are examined, and the electromagnetic field intensity distributions of PNAAs with various Ag thicknesses are simulated. Finally, the fluorescence enhancement factor (FEF) of the fabricated PNAA MEF substrate is measured using spotted Cy5-conjugated streptavidin to indicate a maximum enhancement factor of ~22× for the PNAA with an Ag layer thickness of 75 nm. The experimental results are shown to match the simulated results.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xixi Chen ◽  
Tianli Wu ◽  
Zhiyong Gong ◽  
Jinghui Guo ◽  
Xiaoshuai Liu ◽  
...  

AbstractUsing a single biological element as a photonic component with well-defined features has become a new intriguing paradigm in biophotonics. Here we show that endogenous lipid droplets in the mature adipose cells can behave as fully biocompatible microlenses to strengthen the ability of microscopic imaging as well as detecting intra- and extracellular signals. By the assistance of biolenses made of the lipid droplets, enhanced fluorescence imaging of cytoskeleton, lysosomes, and adenoviruses has been achieved. At the same time, we demonstrated that the required excitation power can be reduced by up to 73%. The lipidic microlenses are finely manipulated by optical tweezers in order to address targets and perform their real-time imaging inside the cells. An efficient detecting of fluorescence signal of cancer cells in extracellular fluid was accomplished due to the focusing effect of incident light by the lipid droplets. The lipid droplets acting as endogenous intracellular microlenses open the intriguing route for a multifunctional biocompatible optics tool for biosensing, endoscopic imaging, and single-cell diagnosis.


2019 ◽  
Vol 11 (20) ◽  
pp. 2630-2633
Author(s):  
Qirong Deng ◽  
Nan Wang ◽  
Jianke Su ◽  
Aijuan Liu ◽  
Jin Zhang ◽  
...  

Herein, a novel carbazole derivative of BEVC was designed with an enhanced fluorescence signal by a G-quadruplex, and thus a fluorescent probe of G-quadruplex/BEVC was obtained by aggregation-induced emission, which could exhibit a decreased fluorescence signal in the presence of Cu2+via the Fenton reaction, demonstrating great potential for Cu2+ assay in pure aqueous solution.


Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3874 ◽  
Author(s):  
Naseem Abbas ◽  
Xun Lu ◽  
Mohsin Ali Badshah ◽  
Jung Bin In ◽  
Won Il Heo ◽  
...  

The detection of body fluids has been used to identify a suspect and build a criminal case. As the amount of evidence collected at a crime site is limited, a multiplex identification system for body fluids using a small amount of sample is required. In this study, we proposed a multiplex detection platform using an Ag vertical nanorod metal enhanced fluorescence (MEF) substrate for semen and vaginal fluid (VF), which are important evidence in cases of sexual crime. The Ag nanorod MEF substrate with a length of 500 nm was fabricated by glancing angle deposition, and amino functionalization was conducted to improve binding ability. The effect of incubation time was analyzed, and an incubation time of 60 min was selected, at which the fluorescence signal was saturated. To assess the performance of the developed identification chip, the identification of semen and VF was carried out. The developed sensor could selectively identify semen and VF without any cross-reactivity. The limit of detection of the fabricated microarray chip was 10 times better than the commercially available rapid stain identification (RSID) Semen kit.


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