scholarly journals A Sensitive FRET Biosensor Based on Carbon Dots-Modified Nanoporous Membrane for 8-hydroxy-2′-Deoxyguanosine (8-OHdG) Detection with Au@ZIF-8 Nanoparticles as Signal Quenchers

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2044
Author(s):  
Weiwei Ye ◽  
Yu Zhang ◽  
Wei Hu ◽  
Liwen Wang ◽  
Yu Zhang ◽  
...  

A sensitive fluorescence resonance energy transfer (FRET) biosensor is proposed to detect 8-hydroxy-2′-deoxyguanosine (8-OHdG), which is a typical DNA oxidation damage product excreted in human urine. The FRET biosensor was based on carbon dots (CDs)-modified nanoporous alumina membrane with CDs as fluorescence donors. Gold nanoparticles were encapsulated in zeolitic imidazolate framework-8 to form Au@ZIF-8 nanoparticles as signal quenchers. CDs and Au@ZIF-8 nanoparticles were biofunctionalized by 8-OHdG antibody. The capture of 8-OHdG on the membrane substrates can bring Au@ZIF-8 nanoparticles closely to CDs. With 350 nm excitation, the fluorescence of CDs was quenched by Au@ZIF-8 nanoparticles and FRET effect occurred. The quenching efficiency was analyzed. The limit of detection (LOD) was 0.31 nM. Interference experiments of the FRET biosensor showed good specificity for 8-OHdG detection. The biosensor could detect urinary 8-OHdG sensitively and selectively with simple sample pretreatment processes. It shows applicability for detecting biomarkers of DNA damage in urine or other biological fluids.

2021 ◽  
Author(s):  
Alagan Muthurasu ◽  
V GANESH

Carbon dots (CDs) exhibiting fluorescence property are generally derived from carbonaceous materials and possessing ultra small size with various exciting physical, chemical and photo-properties that have been used in many...


Nanomedicine ◽  
2021 ◽  
Author(s):  
Abolghasem Abbasi Kajani ◽  
Masoud Ayatollahi Mehrgardi

Aim: To develop a novel theranostic nanoplatform for simultaneous fluorescent monitoring and stimuli-triggered drug delivery. Materials & methods: Different microscopic and spectroscopic techniques were used for the characterization of nanocarriers. MCF-7 and human umbilical vein endothelial cell lines were cultured and treated with different doses of doxorubicin-loaded nanocarriers. The cell viability and drug release were studied using MTT assay and fluorescence microscopy. Results: Biocompatible and mono-disperse nanocarriers represent hollow and mesoporous structures with the calculated surface area of 552.83 m2.g-1, high magnetic activity (12.6 emu.g-1), appropriate colloidal stability and high drug loading capacity (up to 61%). Conclusion: Taxane-based carbon dots act as the pH-responsive gatekeepers for the controlled release of doxorubicin into cancer cells and provide a fluorescence resonance energy transfer system for real-time monitoring of drug delivery.


2021 ◽  
Author(s):  
Ritika Gupta ◽  
Sunaina Kaul ◽  
Vishal Singh ◽  
Sandeep Kumar ◽  
Nitin Kumar Singhal

Abstract For maintaining the healthy metabolic status, vitamin D is a beneficial metabolite stored majorly in its pre-activated form, 25-hydroxyvitamin D3 (25(OH)D3). Due to its important role in bone strengthening, the study was planned to quantify 25(OH)D3 levels in our blood. Quantification techniques for 25(OH)D3 are costly thus requiring a need for a low cost, and sensitive detection methods. In this work, an economic, and sensitive sensor for the detection of 25(OH)D3 was developed using aptamer and graphene oxide (GO). Aptamer is an oligonucleotide, sensitive towards its target, whereas, GO with 2D nanosheets provides excellent quenching surface. Aptamer labeled with fluorescein (5’, 6-FAM) is adsorbed by π -π interaction on the GO sheets leading to quenching of the fluorescence due to Förster resonance energy transfer (FRET). However, in the presence of 25(OH)D3, a major portion of aptamer fluorescence remains unaltered, due to its association with 25(OH)D3. However, in the absence, aptamer fluorescence gets fully quenched. Fluorescence intensity quenching was monitored using fluorescence spectrophotometer and agarose gel based system. The limit of detection of 25(OH)D3 by this method was found to be 0.15 µg/mL. Therefore, this method could come up as a new sensing method in the field of vitamin D detection.


Nanomedicine ◽  
2021 ◽  
Author(s):  
Samuel Bonnet ◽  
Rana Elfatairi ◽  
Florence Franconi ◽  
Emilie Roger ◽  
Samuel Legeay

To understand how nanoparticles (NPs) interact with biological barriers and to ensure they maintain their integrity over time, it is crucial to study their in vivo pharmacokinetic (PK) profiles. Many methods of tracking have been used to describe the in vivo fate of NPs and to evaluate their PKs and structural integrity. However, they do not deliver the same level of information and this may cause misinterpretations. Here, the authors review and discuss the different methods for in vivo tracking of organic NPs. Among them, Förster resonance energy transfer (FRET) presents great potential to track NPs' integrity. However, FRET still requires validated methods to extract and quantify NPs in biological fluids and tissues.


2018 ◽  
Vol 8 ◽  
pp. 184798041882039 ◽  
Author(s):  
Guohua Zhou ◽  
Huimin Jiang ◽  
Yanfang Zhou ◽  
Peilian Liu ◽  
Yongmei Jia ◽  
...  

In recent years, palladium nanoparticles have been proved as energy acceptor candidates in fluorescence resonance energy transfer-based sensors for analytical and biological purposes. In this article, peptide-coated palladium nanoparticles were prepared using a simple one-step preparation method. The peptide Cys-Ala-Leu-Asn-Asn was used as a ligand, whereas hydrazine hydrate was used as a reductant to obtain water-soluble and stable peptide-coated palladium nanoparticles. Additionally, peptide-coated palladium nanoparticles were functionalized by adding the functional peptide CALNNGGARK(FITC) in combination with Cys-Ala-Leu-Asn-Asn during the preparation process. The prepared functionalized peptide-coated palladium nanoparticles were used for trypsin detection based on the fluorescence resonance energy transfer approach. Under optimized conditions, the proposed method can be used for the detection of trypsin concentrations in the range of approximately 0.2–8-μg/mL with a limit of detection of 0.18-μg/mL. The functionalized peptide-coated palladium nanoparticles were successfully applied for the detection of trypsin in urine samples. Our findings also indicated that peptide-coated palladium nanoparticles can highly quench fluorophores and are suitable for the manufacture of off–on state fluorescent sensors. We anticipated that the peptide-coated palladium nanoparticles proposed in this article will have great potential for the detection of trypsin in urine and other analytical, biological, and clinical applications.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jisu Song ◽  
Jin Zhang

Abstract Carbon-dots (CDs), the emerging fluorescent nanoparticles, show special multicolor properties, chemical stability, and biocompatibility, and are considered as the new and advanced imaging probe in replacement of molecular fluorophores and semiconductor quantum dots. However, the requirement of external high power light source limits the application of fluorescent nanomaterials in bio-imaging. The present study aims to take advantage of bioluminescence resonance energy transfer mechanism (BRET) in creating self-illuminating C-dots. Renilla luciferase (Rluc) is chosen as the BRET donor molecule. Conjugation of Renilla luciferase and C-dots is necessary to keep their distance close for energy transfer. The optimal condition for achieving BRET is investigated by studying the effects of different factors on the performance of BRET, including the type of conjugation, concentration of carbon dots, and conjugation time. The linear relationship of BRET efficiency as a function of the amount of C-dots in the range of 0.20–0.80 mg/mL is observed. The self-illuminating carbon dots could be applied in bioimaging avoiding the tissue damage from the external high power light source.


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