scholarly journals Paper Sensors Based on Fluorescence Changes of Carbon Nanodots for Optical Detection of Nanomaterials

2021 ◽  
Vol 13 (21) ◽  
pp. 11896
Author(s):  
Evie L. Papadopoulou ◽  
Giulia Biffi ◽  
Anitha Senthamizhan ◽  
Beatriz Martín-García ◽  
Riccardo Carzino ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Fluorescence Emission ◽  
Carbon Nanodots ◽  
Practical Applications ◽  
Quenching Mechanisms ◽  
Uv Lamp ◽  
Emission Quenching ◽  
Cellulosic Paper ◽  
Paper Sensor ◽  
Pl Quenching

A paper sensor was designed in order to detect the presence of nanomaterials, such as ZnO and silica nanoparticles, as well as graphene nanoplatelets (GnP), based on fluorescence changes of carbon nanodots. Paper strips were functionalized with carbon nanodots using polyvinyl alcohol (PVA) as binder. The carbon nanodots were highly fluorescent and, hence, rendered the (cellulosic) paper stripes emissive. In the presence of silica and ZnO nanoparticles, the fluorescence emission of the carbon nanodots was quenched and the emission decay was shortened, whereas in the presence of GnP only emission quenching occurred. These different photoluminescence (PL) quenching mechanisms, which are evident from lifetime measurements, convey selectivity to the sensor. The change in fluorescence of the carbon dot-functionalized paper is also evident to the naked eye under illumination with a UV lamp, which enables easy detection of the nanomaterials. The sensor was able to detect the nanomaterials upon direct contact, either by dipping it in their aqueous dispersions, or by sweeping it over their powders. The use of the proposed optical sensor permits the detection of nanomaterials in a straightforward manner, opening new ways for the development of optical sensors for practical applications.

scholarly journals Recent Advancements in Doped/Co-Doped Carbon Quantum Dots for Multi-Potential Applications

2019 ◽  
Vol 5 (2) ◽  
pp. 24 ◽  
Author(s):  
Ganeshlenin Kandasamy
Keyword(s):  
Quantum Dots ◽  
Optical Sensors ◽  
Carbon Nanomaterials ◽  
Synthesis Method ◽  
Carbon Quantum Dots ◽  
Carbon Nanodots ◽  
Synthesis Methods ◽  
Sensing Applications ◽  
Potential Applications ◽  
Co Doped

Carbon quantum dots (CQDs)/carbon nanodots are a new class of fluorescent carbon nanomaterials having an approximate size in the range of 2–10 nm. The majority of the reported review articles have discussed about the development of the CQDs (via simple and cost-effective synthesis methods) for use in bio-imaging and chemical-/biological-sensing applications. However, there is a severe lack of consolidated studies on the recently developed CQDs (especially doped/co-doped) that are utilized in different areas of application. Hence, in this review, we have extensively discussed about the recent development in doped and co-doped CQDs (using elements/heteroatoms—e.g., boron (B), fluorine (F), nitrogen (N), sulphur (S), and phosphorous (P)), along with their synthesis method, reaction conditions, and/or quantum yield (QY), and their emerging multi-potential applications including electrical/electronics (such as light emitting diode (LED) and solar cells), fluorescent ink for anti-counterfeiting, optical sensors (for detection of metal ions, drugs, and pesticides/fungicides), gene delivery, and temperature probing.

scholarly journals Nano-aggregates of furan-2-carbohydrazide derivatives displaying enhanced emission with a bathochromic shift

RSC Advances ◽  
2019 ◽  
Vol 9 (62) ◽  
pp. 36097-36102
Author(s):  
Ge Ding ◽  
Xinchao Wang ◽  
Xiujuan Li ◽  
Hongpan Liu ◽  
Lunxiang Wang ◽  
...  
Keyword(s):  
Bathochromic Shift ◽  
Fluorescence Emission ◽  
Green Light ◽  
Uv Lamp

C1 exhibited obvious AIE phenomena. A change from a lack of fluorescence emission to the emission of yellow-green light under a UV lamp was observed upon the inclusion of water in the solvent.

scholarly journals Influence of PDA Coating on the Structural, Optical and Surface Properties of ZnO Nanostructures

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2438 ◽  
Author(s):  
Daina Damberga ◽  
Viktoriia Fedorenko ◽  
Kārlis Grundšteins ◽  
Şahin Altundal ◽  
Andris Šutka ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Properties ◽  
Optical Sensors ◽  
Zno Nanostructures ◽  
Sensor Applications ◽  
Fundamental Properties ◽  
Model Molecule ◽  
Wide Range ◽  
Pl Quenching

Polydopamine (PDA) is a new biocompatible material, which has prospects in biomedical and sensor applications. Due to functional groups, it can host wide range of biomolecules. ZnO nanostructures are well known templates for optical sensors and biosensors. The combination of ZnO and PDA results in a change of optical properties of ZnO–PDA composites as a shift of photoluminescence (PL) peaks and PL quenching. However, to date, the effect of the PDA layer on fundamental properties of ZnO–PDA nanostructures has not been studied. The presented paper reports on optical and surface properties of novel ZnO–PDA nanocomposites. PDA layers were chemically synthesized on ZnO nanostructures from different solution concentrations of 0.3, 0.4, 0.5 and 0.7 mg/mL. Structure, electronic and optical properties were studied by SEM, Raman, FTIR, diffuse reflectance and photoluminescence methods. The Z-potential of the samples was evaluated in neutral pH (pH = 7.2). The response of the samples towards poly-l-lysine adsorption, as a model molecule, was studied by PL spectroscopy to evaluate the correlation between optical and surface properties. The role of the PDA concentration on fundamental properties was discussed.

A perylene monoimide probe based fluorescent micelle sensor for the selective and sensitive detection of picric acid

2020 ◽  
Vol 12 (44) ◽  
pp. 5353-5359
Author(s):  
Weiqing Li ◽  
Huipeng Zhou ◽  
Muhammad Azhar Hayat Nawaz ◽  
Niu Niu ◽  
Na Yang ◽  
...  
Keyword(s):  
Picric Acid ◽  
Fluorescence Emission ◽  
Sensitive Detection ◽  
Quenching Mechanism ◽  
Excimer Fluorescence ◽  
Emission Quenching ◽  
Triton X

A PMI-OH@Triton X-100 micelle sensor based on the perylene probe excimer fluorescence emission quenching mechanism has been developed for the detection of picric acid (PA).

Label-Free Fluorescence-Based Aptasensor for the Detection of Sulfadimethoxine in Water and Fish

2019 ◽  
Vol 73 (3) ◽  
pp. 294-303 ◽  
Author(s):  
Xiang-Xiu Chen ◽  
Zheng-Zhong Lin ◽  
Cheng-Yi Hong ◽  
Hui-Ping Zhong ◽  
Qiu-Hong Yao ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
High Sensitivity ◽  
Inner Filter Effect ◽  
Label Free ◽  
Maximum Residue Limit ◽  
Practical Applications ◽  
Specific Recognition ◽  
Ideal Selectivity ◽  
Fish Samples ◽  
Aquaculture Water

Fluorescence-based aptasensors possess high sensitivity but are complicated and usually require multistep labeling and modification in method design, which severely limit the practical applications. Here, a label-free fluorescence-based aptasensor, consisting of aptamer, gold nanoparticles (AuNPs), and cadmium telluride (CdTe) quantum dots (QDs), was developed for the detection of sulfadimethoxine (SDM) in water and fish based on the specific recognition of SDM-aptamer and the inner filter effect of QDs and AuNPs. In the absence of a target, AuNPs dispersed in salt solution because of the aptamer protection, which could effectively quench the fluorescence emission of QDs, while in the presence of SDM, AuNPs aggregated due to the specific recognition of SDM-aptamer to SDM, which resulted in fluorescence recovery. A linear response of SDM concentrations in the range of 10–250 ng mL−1 ( R2 = 0.99) was obtained, and the detection limit was 1.54 ng mL−1 (3σ, n = 9), far below the maximum residue limit (100 ng mL−1) of SDM in edible animal tissues regulated by China and the European Commission. The fluorescence-based aptasensor was applied to the detection of SDM in aquaculture water and fish samples with high accuracy, excellent precision, and ideal selectivity. The results indicated that the developed aptasensor was simple in design, easy to operate, and could be used to detect rapidly and accurately SDM in water and fish samples.

scholarly journals Fluorescence Enhancement Using Bimetal Surface Plasmon-Coupled Emission from 5-Carboxyfluorescein (FAM)

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 460 ◽  
Author(s):  
Nhu Tran ◽  
Kieu Trinh ◽  
Jun-Ho Lee ◽  
Won Yoon ◽  
Heongkyu Ju
Keyword(s):  
Surface Plasmons ◽  
Surface Plasmon ◽  
Coefficient Of Variation ◽  
Fluorescence Enhancement ◽  
Fluorescence Emission ◽  
High Reproducibility ◽  
Practical Applications ◽  
Biochemical Assays ◽  
Gold Silver ◽  
Spectral Channels

We demonstrate the enhancement of fluorescence emission from a dye, 5-carboxyfluorescein (FAM), which couples with surface plasmons at the spectral channels of excitation and emission. Experiments and calculations revealed that bimetallic (gold-silver) plasmon, as compared to the monometallic ones, allowed such coupling to be enhanced, at both the spectral channels. We achieved the maximum fluorescence enhancement level of 46.5-fold, with markedly high reproducibility (coefficient of variation ~ 0.5%) at a FAM concentration of 10 nM. We also found that higher fluorescence enhancement was more likely to be reproducible. This encourages the use of this technology for practical applications in fluorescence-based biochemical assays. Moreover, we investigated a FAM concentration-dependent enhancement of fluorescence. It was found that fluorescence enhancement decreased and saturated at above 10 nM concentration possibly due to partial photo-bleaching of FAM molecules.

scholarly journals A Metal-Based Receptor for Selective Coordination and Fluorescent Sensing of Chloride

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2352
Author(s):  
Mauro Formica ◽  
Vieri Fusi ◽  
Daniele Paderni ◽  
Gianluca Ambrosi ◽  
Mario Inclán ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Fluorescence Emission ◽  
Chloride Anion ◽  
Fluorescent Sensing ◽  
Pendant Arm ◽  
Uv Lamp ◽  
Bound Chloride

A scorpionate Zn2+ complex, constituted by a macrocyclic pyridinophane core attached to a pendant arm containing a fluorescent pyridyl-oxadiazole-phenyl unit (PyPD), has been shown to selectively recognize chloride anions, giving rise to changes in fluorescence emission that are clearly visible under a 365 nm UV lamp. This recognition event has been studied by means of absorption, fluorescence, and NMR spectroscopy, and it involves the intramolecular displacement of the PyPD unit by chloride anions. Moreover, since the chromophore is not removed from the system after the recognition event, the fluorescence can readily be restored by elimination of the bound chloride anion.

scholarly journals Carbon nanodot–based electrogenerated chemiluminescence biosensor for miRNA-21 detection

2021 ◽  
Vol 188 (11) ◽  
Author(s):  
Laura Gutiérrez-Gálvez ◽  
Tania García-Mendiola ◽  
Cristina Gutiérrez-Sánchez ◽  
Tamara Guerrero-Esteban ◽  
Cristina García-Diego ◽  
...  
Keyword(s):  
Rna Extraction ◽  
Synthesis Method ◽  
Fluorescence Emission ◽  
Morphological Characteristics ◽  
Electrogenerated Chemiluminescence ◽  
Carbon Nanodots ◽  
Serum Samples ◽  
Double Stranded Dna ◽  
New Synthesis ◽  
Amplification Process

AbstractA simple carbon nanodot–based electrogenerated chemiluminescence biosensor is described for sensitive and selective detection of microRNA-21 (miRNA-21), a biomarker of several pathologies including cardiovascular diseases (CVDs). The photoluminescent carbon nanodots (CNDs) were obtained using a new synthesis method, simply by treating tiger nut milk in a microwave reactor. The synthesis is environmentally friendly, simple, and efficient. The optical properties and morphological characteristics of the CNDs were exhaustively investigated, confirming that they have oxygen and nitrogen functional groups on their surfaces and exhibit excitation-dependent fluorescence emission, as well as photostability. They act as co-reactant agents in the anodic electrochemiluminescence (ECL) of [Ru(bpy)3]2+, producing different signals for the probe (single-stranded DNA) and the hybridized target (double-stranded DNA). These results paved the way for the development of a sensitive ECL biosensor for the detection of miRNA-21. This was developed by immobilization of a thiolated oligonucleotide, fully complementary to the miRNA-21 sequence, on the disposable gold electrode. The target miRNA-21 was hybridized with the probe on the electrode surface, and the hybridization was detected by the enhancement of the [Ru(bpy)3]2+/DNA ECL signal using CNDs. The biosensor shows a linear response to miRNA-21 concentration up to 100.0 pM with a detection limit of 0.721 fM. The method does not require complex labeling steps, and has a rapid response. It was successfully used to detect miRNA-21 directly in serum samples from heart failure patients without previous RNA extraction neither amplification process. Graphical abstract

scholarly journals Fluorescent Thienothiophene-Containing Squaraine Dyes and Threaded Supramolecular Complexes with Tunable Wavelengths between 600–800 nm

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2229 ◽  
Author(s):  
Wenqi Liu ◽  
Hannah McGarraugh ◽  
Bradley Smith
Keyword(s):  
Near Infrared ◽  
Fluorescence Emission ◽  
Supramolecular Complex ◽  
Spectral Studies ◽  
Practical Applications ◽  
Squaraine Dyes ◽  
Guided Surgery ◽  
New Family ◽  
Fluorescence Guided Surgery ◽  
Purification Methods

A new family of fluorescent thiophene and thienothiophene-containing squaraine dyes is described with tunable wavelengths that cover the absorption/emission range of 600–800 nm. The deep-red and near-infrared fluorescent compounds were easily prepared by simple synthesis and purification methods. Spectral studies showed that each squaraine was rapidly encapsulated by a tetralactam macrocycle, with nanomolar affinity in water, to produce a threaded supramolecular complex with high chemical stability, increased fluorescence quantum yield, and decreased fluorescence quenching upon dye self-aggregation. Energy transfer within the supramolecular complex permitted multiplex emission. That is, two separate dyes with fluorescence emission bands that match the popular Cy5 and Cy7 channels, could be simultaneously excited with a beam of 375 nm light. A broad range of practical applications is envisioned in healthcare diagnostics, microscopy, molecular imaging, and fluorescence-guided surgery.

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