scholarly journals Label-free discrimination of membrane-translocating peptides on porous silicon microfluidic biosensors

2016 ◽  
Vol 10 (6) ◽  
pp. 064113 ◽  
Author(s):  
Zhen Li ◽  
Qiaohui Luo ◽  
Jianmin Wu
Keyword(s):  
Porous Silicon ◽  
Label Free

Porous silicon membrane-modified electrodes for label-free voltammetric detection of MS2 bacteriophage

2016 ◽  
Vol 80 ◽  
pp. 47-53 ◽  
Author(s):  
Nekane Reta ◽  
Andrew Michelmore ◽  
Christopher Saint ◽  
Beatriz Prieto-Simón ◽  
Nicolas H. Voelcker
Keyword(s):  
Porous Silicon ◽  
Modified Electrodes ◽  
Label Free ◽  
Silicon Membrane ◽  
Ms2 Bacteriophage ◽  
Voltammetric Detection

Design and realization of label-free optical immunosensor based on porous silicon microcavities

2008 ◽  
Author(s):  
Xiao-yi Lü ◽  
Tao Xue ◽  
Zhen-hong Jia ◽  
Hua-wei Shao ◽  
Shi-bin Hou ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Label Free ◽  
Optical Immunosensor

scholarly journals Label-Free Virus Capture and Release by a Microfluidic Device Integrated with Porous Silicon Nanowire Forest

Small ◽  
2016 ◽  
Vol 13 (6) ◽  
pp. 1603135 ◽  
Author(s):  
Yiqiu Xia ◽  
Yi Tang ◽  
Xu Yu ◽  
Yuan Wan ◽  
Yizhu Chen ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Microfluidic Device ◽  
Silicon Nanowire ◽  
Label Free ◽  
Free Virus ◽  
Capture And Release ◽  
Porous Silicon Nanowire

scholarly journals A lectin-coupled porous silicon-based biosensor: label-free optical detection of bacteria in a real-time mode

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mona Yaghoubi ◽  
Fereshteh Rahimi ◽  
Babak Negahdari ◽  
Ali Hossein Rezayan ◽  
Azizollah Shafiekhani
Keyword(s):  
Fourier Transform ◽  
Porous Silicon ◽  
Real Time ◽  
Limit Of Detection ◽  
Principal Component ◽  
The Other ◽  
Detection Methods ◽  
Carbohydrate Binding ◽  
Label Free ◽  
E Coli

Abstract Accuracy and speed of detection, along with technical and instrumental simplicity, are indispensable for the bacterial detection methods. Porous silicon (PSi) has unique optical and chemical properties which makes it a good candidate for biosensing applications. On the other hand, lectins have specific carbohydrate-binding properties and are inexpensive compared to popular antibodies. We propose a lectin-conjugated PSi-based biosensor for label-free and real-time detection of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by reflectometric interference Fourier transform spectroscopy (RIFTS). We modified meso-PSiO2 (10–40 nm pore diameter) with three lectins of ConA (Concanavalin A), WGA (Wheat Germ Agglutinin), and UEA (Ulex europaeus agglutinin) with various carbohydrate specificities, as bioreceptor. The results showed that ConA and WGA have the highest binding affinity for E. coli and S. aureus respectively and hence can effectively detect them. This was confirmed by 6.8% and 7.8% decrease in peak amplitude of fast Fourier transform (FFT) spectra (at 105 cells mL−1 concentration). A limit of detection (LOD) of about 103 cells mL−1 and a linear response range of 103 to 105 cells mL−1 were observed for both ConA-E. coli and WGA-S. aureus interaction platforms that are comparable to the other reports in the literature. Dissimilar response patterns among lectins can be attributed to the different bacterial cell wall structures. Further assessments were carried out by applying the biosensor for the detection of Klebsiella aerogenes and Bacillus subtilis bacteria. The overall obtained results reinforced the conjecture that the WGA and ConA have a stronger interaction with Gram-positive and Gram-negative bacteria, respectively. Therefore, it seems that specific lectins can be suggested for bacterial Gram-typing or even serotyping. These observations were confirmed by the principal component analysis (PCA) model.

scholarly journals Botulinum Neurotoxin-C Detection Using Nanostructured Porous Silicon Interferometer

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 228
Author(s):  
Dashananda Nanda Kumar ◽  
Zina Baider ◽  
Daniel Elad ◽  
Shlomo E. Blum ◽  
Giorgi Shtenberg
Keyword(s):  
Porous Silicon ◽  
Optical Biosensor ◽  
Optical Signal ◽  
Practical Aspect ◽  
Farm Animals ◽  
Label Free ◽  
Life Threatening ◽  
Botulinum Neurotoxins ◽  
Evidence Based Therapy

Botulinum neurotoxins (BoNT) are the most potent toxins, which are produced by Clostridium bacteria and cause the life-threatening disease of botulism in all vertebrates. Specifically, animal botulism represents a serious environmental and economic concern in animal production due to the high mortality rates observed during outbreaks. Despite the availability of vaccines against BoNT, there are still many outbreaks of botulism worldwide. Alternative assays capable of replacing the conventional in vivo assay in terms of rapid and sensitive quantification, and the applicability for on-site analysis, have long been perused. Herein, we present a simple, highly sensitive and label-free optical biosensor for real-time detection of BoNT serotype C using a porous silicon Fabry–Pérot interferometer. A competitive immunoassay coupled to a biochemical cascade reaction was adapted for optical signal amplification. The resulting insoluble precipitates accumulated within the nanostructure changed the reflectivity spectra by alternating the averaged refractive index. The augmented optical performance allowed for a linear response within the range of 10 to 10,000 pg mL−1 while presenting a detection limit of 4.8 pg mL−1. The practical aspect of the developed assay was verified using field BoNT holotoxins to exemplify the potential use of the developed optical approach for rapid bio-diagnosis of BoNT. The specificity and selectivity of the assay were successfully validated using an adjacent holotoxin relevant for farm animals (BoNT serotype D). Overall, this work sets the foundation for implementing a miniaturized interferometer for routine on-site botulism diagnosis, thus significantly reducing the need for animal experimentation and shortening analysis turnaround for early evidence-based therapy.

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