scholarly journals Layer-by-layer biofunctionalization of nanostructured porous silicon for high-sensitivity and high-selectivity label-free affinity biosensing

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Stefano Mariani ◽  
Valentina Robbiano ◽  
Lucanos M. Strambini ◽  
Aline Debrassi ◽  
Gabriela Egri ◽  
...  
Keyword(s):  
Porous Silicon ◽  
High Selectivity ◽  
High Sensitivity ◽  
Layer By Layer ◽  
Label Free

Layer-By-Layer Nanoassembly Of Polyelectrolites Engineered With Bioreceptors For High-Sensitivity Optical Label-Free Biosensing With Nanostructured Porous Silicon

2020 ◽  
Vol MA2020-01 (25) ◽  
pp. 1403-1403
Author(s):  
Stefano Mariani ◽  
Valentina Robbiano ◽  
Lucanos M Strambini ◽  
Aline Debrassi ◽  
Gabriela Egri ◽  
...  
Keyword(s):  
Porous Silicon ◽  
High Sensitivity ◽  
Layer By Layer ◽  
Label Free

scholarly journals Capacitive Field-effect (bio-)chemical Sensors Based on Nanocrystalline Diamond Films

2009 ◽  
Vol 1203 ◽  
Author(s):  
Matthias Bäcker ◽  
Arshak Poghossian ◽  
Maryam H. Abouzar ◽  
Sylvia Wenmackers ◽  
Stoffel D. Janssens ◽  
...  
Keyword(s):  
Thin Films ◽  
Field Effect ◽  
High Sensitivity ◽  
Ph Sensitive ◽  
Nanocrystalline Diamond ◽  
Penicillin G ◽  
Layer By Layer ◽  
Label Free ◽  
High Coverage ◽  
Layer Adsorption

AbstractCapacitive field-effect electrolyte-diamond-insulator-semiconductor (EDIS) structures with O-terminated nanocrystalline diamond (NCD) as sensitive gate material have been realized and investigated for the detection of pH, penicillin concentration, and layer-by-layer adsorption of polyelectrolytes. The surface oxidizing procedure of NCD thin films as well as the seeding and NCD growth process on a Si-SiO2 substrate have been improved to provide high pH-sensitive, non-porous thin films without damage of the underlying SiO2 layer and with a high coverage of O-terminated sites. The NCD surface topography, roughness, and coverage of the surface groups have been characterized by SEM, AFM and XPS methods. The EDIS sensors with O-terminated NCD film treated in oxidizing boiling mixture for 45 min show a pH sensitivity of about 50 mV/pH. The pH-sensitive properties of the NCD have been used to develop an EDIS-based penicillin biosensor with high sensitivity (65-70 mV/decade in the concentration range of 0.25-2.5 mM penicillin G) and low detection limit (5 μM). The results of label-free electrical detection of layer-by-layer adsorption of charged polyelectrolytes are presented, too.

scholarly journals Rapid Determination of Ochratoxin A in Grape and Its Commodities Based on a Label-Free Impedimetric Aptasensor Constructed by Layer-by-Layer Self-Assembly

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 71 ◽  
Author(s):  
Mina Nan ◽  
Yang Bi ◽  
Huali Xue ◽  
Sulin Xue ◽  
Haitao Long ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Self Assembly ◽  
Electrochemical Impedance ◽  
Rapid Determination ◽  
Grape Juice ◽  
High Sensitivity ◽  
Layer By Layer ◽  
Label Free ◽  
Transfer Resistance

A simple and sensitive label-free impedimetric aptasensor for rapid determination of ochratoxin A (OTA) has been developed, which was based on the combination between thiolated aptamer and gold nanoparticles by layer-by-layer self-assembly. Because of the interaction between aptamer and OTA, the relative normalized electron-transfer resistance (ΔRct) values obtained by electrochemical impedance spectroscopy (EIS) was proportional to the concentration of OTA and showed a good linear relationship from 0.1 to 10.0 ng/mL, with a lower detection limit (0.030 ng/mL) than one-step thiolated DNA aptasensor. The established method was successfully applied to detect and analyze OTA in table wine and grape juice, and the recovery was 90.56%–104.21% when PVP effective removed of phenolic substances. The label-free impedimetric aptasensor was used for rapid detection and quantitation of OTA in the inoculated grapes with the Aspergillus Nigri (H1), and the production of OTA (62.4 μg/kg, 20 μg/kg) far exceeded the maximum levels of 2 μg/kg after inoculation for three days. The developed method exhibited a good specificity, high sensitivity, time-efficient, and it could be applied to detect the OTA concentration in grape and its commodities.

scholarly journals A Label-Free Fluorescent Assay for the Rapid and Sensitive Detection of Adenosine Deaminase Activity and Inhibition

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2441 ◽  
Author(s):  
Xinxing Tang ◽  
Kefeng Wu ◽  
Han Zhao ◽  
Mingjian Chen ◽  
Changbei Ma
Keyword(s):  
Adenosine Deaminase ◽  
High Selectivity ◽  
High Sensitivity ◽  
Rnase H ◽  
Fluorescence Signal ◽  
Label Free ◽  
Fluorescent Assay ◽  
Adenosine Deaminase Activity ◽  
G Quadruplex ◽  
Almost All

Adenosine deaminase (ADA), able to catalyze the irreversible deamination of adenosine into inosine, can be found in almost all tissues and plays an important role in several diseases. In this work, we developed a label-free fluorescence method for the detection of adenosine deaminase activity and inhibition. In the presence of ADA, ATP has been shown to be hydrolyzed. The ATP aptamer was shown to form a G-quadruplex/thioflavin T (ThT) complex with ThT and exhibited an obvious fluorescence signal. However, the ATP aptamer could bind with ATP and exhibited a low fluorescence signal because of the absence of ADA. This assay showed high sensitivity to ADA with a detection limit of 1 U/L based on an SNR of 3 and got a good linear relationship within the range of 1–100 U/L with R2 = 0.9909. The LOD is lower than ADA cutoff value (4 U/L) in the clinical requirement and more sensitive than most of the reported methods. This technique exhibited high selectivity for ADA against hoGG I, UDG, RNase H and λexo. Moreover, this strategy was successfully applied for assaying the inhibition of ADA using erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) and, as such, demonstrated great potential for the future use in the diagnosis of ADA-relevant diseases, particularly in advanced drug development.

scholarly journals Porous Silicon-Based Aptasensors: The Next Generation of Label-Free Devices for Health Monitoring

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2216 ◽  
Author(s):  
Monica Terracciano ◽  
Ilaria Rea ◽  
Nicola Borbone ◽  
Rosalba Moretta ◽  
Giorgia Oliviero ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Porous Silicon ◽  
Limit Of Detection ◽  
Combinatorial Libraries ◽  
High Sensitivity ◽  
Label Free ◽  
Great Specificity ◽  
Silicon Based ◽  
Exponential Enrichment

Aptamers are artificial nucleic acid ligands identified and obtained from combinatorial libraries of synthetic nucleic acids through the in vitro process SELEX (systematic evolution of ligands by exponential enrichment). Aptamers are able to bind an ample range of non-nucleic acid targets with great specificity and affinity. Devices based on aptamers as bio-recognition elements open up a new generation of biosensors called aptasensors. This review focuses on some recent achievements in the design of advanced label-free optical aptasensors using porous silicon (PSi) as a transducer surface for the detection of pathogenic microorganisms and diagnostic molecules with high sensitivity, reliability and low limit of detection (LoD).

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