scholarly journals Portable on-chip colorimetric biosensing platform integrated with a smartphone for label/PCR-free detection of Cryptosporidium RNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
George S. Luka ◽  
Ephraim Nowak ◽  
Quin Robert Toyata ◽  
Nishat Tasnim ◽  
Homayoun Najjaran ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Colorimetric Assay ◽  
Cost Effective ◽  
Naked Eye ◽  
Sensing Platform ◽  
3D Printed ◽  
Protozoan Pathogen ◽  
On Chip ◽  
Colorimetric Biosensing

AbstractCryptosporidium, a protozoan pathogen, is a leading threat to public health and the economy. Herein, we report the development of a portable, colorimetric biosensing platform for the sensitive, selective and label/PCR-free detection of Cryptosporidium RNA using oligonucleotides modified gold nanoparticles (AuNPs). A pair of specific thiolated oligonucleotides, complementary to adjacent sequences on Cryptosporidium RNA, were attached to AuNPs. The need for expensive laboratory-based equipment was eliminated by performing the colorimetric assay on a micro-fabricated chip in a 3D-printed holder assembly. A smartphone camera was used to capture an image of the color change for quantitative analysis. The detection was based on the aggregation of the gold nanoparticles due to the hybridization between the complementary Cryptosporidium RNA and the oligonucleotides immobilized on the AuNPs surface. In the complementary RNA’s presence, a distinctive color change of the AuNPs (from red to blue) was observed by the naked eye. However, in the presence of non-complementary RNA, no color change was observed. The sensing platform showed wide linear responses between 5 and 100 µM with a low detection limit of 5 µM of Cryptosporidium RNA. Additionally, the sensor developed here can provide information about different Cryptosporidium species present in water resources. This cost-effective, easy-to-use, portable and smartphone integrated on-chip colorimetric biosensor has great potential to be used for real-time and portable POC pathogen monitoring and molecular diagnostics.

scholarly journals 3D printed microfluidic lab-on-a-chip device for fiber-based dual beam optical manipulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haoran Wang ◽  
Anton Enders ◽  
John-Alexander Preuss ◽  
Janina Bahnemann ◽  
Alexander Heisterkamp ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Single Cells ◽  
Lab On A Chip ◽  
Cost Effective ◽  
Optical Manipulation ◽  
Hydrodynamic Focusing ◽  
Trapping Region ◽  
Dual Beam ◽  
3D Printed ◽  
On Chip

Abstract3D printing of microfluidic lab-on-a-chip devices enables rapid prototyping of robust and complex structures. In this work, we designed and fabricated a 3D printed lab-on-a-chip device for fiber-based dual beam optical manipulation. The final 3D printed chip offers three key features, such as (1) an optimized fiber channel design for precise alignment of optical fibers, (2) an optically clear window to visualize the trapping region, and (3) a sample channel which facilitates hydrodynamic focusing of samples. A square zig–zag structure incorporated in the sample channel increases the number of particles at the trapping site and focuses the cells and particles during experiments when operating the chip at low Reynolds number. To evaluate the performance of the device for optical manipulation, we implemented on-chip, fiber-based optical trapping of different-sized microscopic particles and performed trap stiffness measurements. In addition, optical stretching of MCF-7 cells was successfully accomplished for the purpose of studying the effects of a cytochalasin metabolite, pyrichalasin H, on cell elasticity. We observed distinct changes in the deformability of single cells treated with pyrichalasin H compared to untreated cells. These results demonstrate that 3D printed microfluidic lab-on-a-chip devices offer a cost-effective and customizable platform for applications in optical manipulation.

Visual detection of 8-OHdG based on the aggregation of gold nanoparticles capped with the anti-8-OHdG antibody

2015 ◽  
Vol 7 (19) ◽  
pp. 8360-8365 ◽  
Author(s):  
Liping Wu ◽  
Wendan Pu ◽  
Yue Liu ◽  
Huawen Zhao ◽  
Weiqun Shu
Keyword(s):  
Gold Nanoparticles ◽  
Quantitative Determination ◽  
Rapid Method ◽  
Visual Detection ◽  
Color Change ◽  
Naked Eye ◽  
Absorption Wavelength

AuNPs, capped with anti-8-OHdG antibody, aggregate when 8-OHdG was added, resulting in color change and redshift of absorption wavelength. So a simple and rapid method to selectively determine 8-OHdG was developed and semi-quantitative determination could be achieved by the naked eye.

scholarly journals A Highly Sensitive and Selective Colorimetric Hg2+ Ion Probe Using Gold Nanoparticles Functionalized with Polyethyleneimine

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Kyung Min Kim ◽  
Yun-Sik Nam ◽  
Yeonhee Lee ◽  
Kang-Bong Lee
Keyword(s):  
Gold Nanoparticles ◽  
Secondary Ion Mass Spectrometry ◽  
Color Change ◽  
Colorimetric Assay ◽  
Tap Water ◽  
Interparticle Distance ◽  
Pond Water ◽  
Assay Method ◽  
Tuna Fish ◽  
Highly Sensitive

A highly sensitive and selective colorimetric assay for the detection of Hg2+ ions was developed using gold nanoparticles (AuNPs) conjugated with polyethyleneimine (PEI). The Hg2+ ion coordinates with PEI, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the Hg2+ ion was bound to the nitrogen atoms of the PEI in a bidentate manner (N–Hg2+–N), which resulted in a significant color change from light red to violet due to aggregation. Using this PEI-AuNP probe, determination of Hg2+ ion can be achieved by the naked eye and spectrophotometric methods. Pronounced color change of the PEI-AuNPs in the presence of Hg2+ was optimized at pH 7.0, 50°C, and 300 mM·NaCl concentration. The absorption intensity ratio (A700/A514) was correlated with the Hg2+ concentration in the linear range of 0.003–5.0 μM. The limits of detection were measured to be 1.72, 1.80, 2.00, and 1.95 nM for tap water, pond water, tuna fish, and bovine serum, respectively. Owing to its facile and sensitive nature, this assay method for Hg2+ ions can be applied to the analysis of water and biological samples.

scholarly journals Development of RNA-based assay for rapid detection of SARS-CoV-2 in clinical samples

2020 ◽  
Author(s):  
Vinod Kumar ◽  
Suman Mishra ◽  
Rajni Sharma ◽  
Jyotsana Agarwal ◽  
Ujjala Ghoshal ◽  
...  
Keyword(s):  
Colorimetric Assay ◽  
Cost Effective ◽  
Clinical Samples ◽  
Visible Range ◽  
Gold Colloid ◽  
Rt Pcr ◽  
Sensing Platform ◽  
Effective Manner ◽  
The Subject ◽  
Induced Aggregation

AbstractThe ongoing spread of pandemic coronavirus disease (COVID-19) is caused by Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2). In the lack of specific drugs or vaccines for SARS-CoV-2, demands rapid diagnosis and management are crucial for controlling the outbreak in the community. Here we report the development of the first rapid-colorimetric assay capable of detecting SARS-CoV-2 in the human nasopharyngeal RNA sample in less than 30 minutes. We utilized a nanomaterial-based optical sensing platform to detect RNA-dependent RNA polymerase (RdRp) gene of SARS-CoV-2, where the formation of oligo probe-target hybrid led to salt-induced aggregation and changes in gold-colloid color from pink to blue in visible range. Accordingly, we found a change in colloid color from pink to blue in assay containing nasopharyngeal RNA sample from the subject with clinically diagnosed COVID-19. The colloid retained pink color when the test includes samples from COVID-19 negative subjects or human papillomavirus (HPV) infected women. The results were validated using nasopharangeal RNA samples from suspected COVID-19 subjects (n=136). Using RT-PCR as gold standard, the assay was found to have 85.29% sensitivity and 94.12% specificity. The optimized method has detection limit as little as 0.5 ng of SARS-CoV-2 RNA. Overall, the developed assay rapidly detects SARS-CoV-2 RNA in clinical samples in a cost-effective manner and would be useful in pandemic management by facilitating mass screening.

Microfluidic paper-based analytical device using gold nanoparticles modified with N,N′-bis(2-hydroxyethyl)dithiooxamide for detection of Hg(ii) in air, fish and water samples

2020 ◽  
Vol 44 (43) ◽  
pp. 18662-18667
Author(s):  
Sattar Shariati ◽  
Gholamreza Khayatian
Keyword(s):  
Gold Nanoparticles ◽  
Water Samples ◽  
Visual Detection ◽  
Color Change ◽  
Digital Camera ◽  
New Method ◽  
Naked Eye ◽  
Analytical Device

A new method for visual detection of mercury by color change is developed that can detect Hg2+ by the naked eye or a digital camera.

scholarly journals Epitaxial Graphene Sensors Combined with 3D Printed Microfluidic Chip for Heavy Metals Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 982 ◽  
Author(s):  
Maria Francesca Santangelo ◽  
Ivan Shtepliuk ◽  
Donatella Puglisi ◽  
Daniel Filippini ◽  
Rositsa Yakimova ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Microfluidic Chip ◽  
Chemical Interaction ◽  
High Sensitivity ◽  
Epitaxial Graphene ◽  
Phase Detection ◽  
Lab On Chip ◽  
Sensing Platform ◽  
3D Printed ◽  
On Chip

Two-dimensional materials may constitute key elements in the development of a sensing platform where extremely high sensitivity is required, since even minimal chemical interaction can generate appreciable changes in the electronic state of the material. In this work, we investigate the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb). The integration of preparatory steps needed for sample conditioning is included in the sensing platform, exploiting fast prototyping using a 3D printer, which allows direct fabrication of a microfluidic chip incorporating all the features required to connect and execute the Lab-on-chip (LOC) functions. It is demonstrated that interaction of Pb2+ ions in water-based solutions with the EG enhances its conductivity exhibiting a Langmuir correlation between signal and Pb2+ concentration. Several concentrations of Pb2+ solutions ranging from 125 nM to 500 µM were analyzed showing good stability and reproducibility over time.

Colorimetric Sensing of Methyl Parathion Using Nanozymatic Activity of Gold Nanoparticles

2020 ◽  
Vol 12 (2) ◽  
pp. 232-241
Author(s):  
Anjana Pandey ◽  
Saumya Srivastava ◽  
Gayatri ◽  
Priya Rai ◽  
Ashutosh Pandey
Keyword(s):  
Gold Nanoparticles ◽  
Methyl Parathion ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Cost Effective ◽  
Colorimetric Sensing ◽  
Electron Transfer Mechanism ◽  
Au Nps ◽  
New Approach ◽  
Cost Effective Technique

In this study, we have used new approach for detection of the methyl parathion residues i.e., by inhibiting half of the peroxidase-like activity of gold nanoparticles. We have investigated the peroxidase like activity of gold nanoparticles by colorimetric assay and optimized the pH, temperature, incubation time and different concentrations of H2O2 by using TMB as substrate as well as organophosphates effect on their enzyme mimetic activity. Kinetic study of gold nanoparticles has shown better catalytic activity than horseradish peroxidase at pH 3.5. The peroxidase substrate TMB (3,3,5,5-tetramethylbenzidine) can be oxidized by H2O2 by the enzymatic action of the gold nanoparticles resulting in a blue-coloured product, oxidized TMB. The principle involved behind the inhibition of enzymatic activity of nanozyme is due to hindrance of electron transfer mechanism TMB-H2O2-Au NPs system by the methyl parathion. The peroxidase activity is selectively reduced with increasing methyl parathion concentration. This sensing method has lowest limit of detection of 78.95 nM. This study can be used for development of sensitive and cost effective technique for sensing of harmful pesticides.

Non-enzymatic colorimetric sensor strip based on melamine-functionalized gold nanoparticles assembled on polyamide nanofiber membranes for the detection of metronidazole

2019 ◽  
Vol 11 (29) ◽  
pp. 3706-3713 ◽  
Author(s):  
Mohammed Awad Abedalwafa ◽  
Yan Li ◽  
Chunfang Ni ◽  
Gang Yang ◽  
Lu Wang
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
High Sensitivity ◽  
Colorimetric Sensor ◽  
Eye Detection ◽  
Naked Eye ◽  
Functionalized Gold Nanoparticles ◽  
Sensitivity And Selectivity ◽  
Nanofiber Membranes ◽  
Naked Eye Detection

Non-enzymatic colorimetric sensor strip for detection of metronidazole (MTZ) was designed and constructed, with high sensitivity and selectivity. Which can be used for naked-eye detection of MTZ with a visible color change from pink to purple.

scholarly journals A Facile Strategy for Immobilizing GOD and HRP onto Pollen Grain and Its Application to Visual Detection of Glucose

2020 ◽  
Vol 21 (24) ◽  
pp. 9529
Author(s):  
Shanxia Jin ◽  
Liping Liu ◽  
Mengying Fan ◽  
Yaru Jia ◽  
Ping Zhou
Keyword(s):  
Visual Detection ◽  
Color Change ◽  
Cost Effective ◽  
Pollen Grain ◽  
Practical Application ◽  
Horse Radish Peroxidase ◽  
Experimental Conditions ◽  
Naked Eye ◽  
Cost Effective Approach ◽  
Affinity Interaction

Pollen grain was explored as a new carrier for enzyme immobilization. After being modified with boric acid-functionalized titania, the pollen grain was able to covalently immobilize glycosylated enzymes by boronate affinity interaction under very mild experimental conditions (e.g., pH 7.0, ambient temperature and free of organic solvent). The glucose oxidase and horse radish peroxidase-immobilized pollen grain became a bienzyme system. The pollen grain also worked as an indicator of the cascade reaction by changing its color. A rapid, simple and cost-effective approach for the visual detection of glucose was then developed. When the glucose concentration exceeded 0.5 mM, the color change was observable by the naked eye. The assay of glucose in body fluid samples exhibited its great potential for practical application.

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