Quantum Dot Encoding of Aptamer-Linked Nanostructures for One-Pot Simultaneous Detection of Multiple Analytes

2007 ◽  
Vol 79 (11) ◽  
pp. 4120-4125 ◽  
Author(s):  
Juewen Liu ◽  
Jung Heon Lee ◽  
Yi Lu
Author(s):  
Shancy Augustine ◽  
Pan Gu ◽  
Xiangjun Zheng ◽  
Toshikazu Nishida ◽  
Z. Hugh Fan

There is a need for low-cost immunoassays that measure the presence and concentration of multiple harmful agents in one device. Currently, comparable immunoassays employ a one-analyte-per-test format that is time consuming and not cost effective for the requirement of detecting multiple analytes in a single sample. For instance, if a spectrum of harmful agents, including E. coli O157, cholera toxin, and Salmonella typhimurium, should be simultaneously monitored in foods and drinking water, then a one-analyte-per-test would be inefficient. This work demonstrates a platform capable of simultaneous detection of multiple analytes in a single, low-cost, microvalve array-enabled multiplexed immunoassay. This multiplexed immunoassay platform is demonstrated in a prototype COC (cyclic olefin copolymer) device with a 2×3 array in which 6 analytes can be detected simultaneously. In order to contain and regulate the flow of reagents in the multichannel device, an array of microfluidic valves actuated by a thermally expandable material and microfabricated resistors have been developed to direct the flow to the necessary assay sites. The microvalve-based immunoassay is shown to be reliable, easy to operate, and compatible with large-scale integration. The all-plastic microvalves use paraffin wax as the thermally sensitive material which drastically reduces power consumption by latching upon closing so that pulsed power is required only to close and latch the microvalve until it is necessary to re-open the valve. The multiplexed detection scheme has been demonstrated by using three proteins, C reactive protein (CRP) and transferrin, both of which are biomarkers associated with traumatic brain injury (TBI) as well as bovine serum albumin (BSA) as the negative control. Since there are no external bulky pneumatic accessories required to operate/latch the microvalves in the device, this compact, thermally actuated and latching microvalve-enabled multiplexed immunoassay has the potential to realize a portable, low power, battery operated microfluidic device for biological assays.


2020 ◽  
Vol 16 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Ravi Arunan ◽  
Printo Joseph ◽  
Muthusamy Sivakumar ◽  
Suthanthira Cross Guevara Kiruba Daniel

Background: Mn doped ZnS is selected as the right element which is prominent among quantum dot for its high luminescent and quantum yield property and also non toxicity while comparing with other organometallic quantum dot synthesized by using different capping agents. Methods: An interesting observation based on colorimetric sensing of dopamine using manganese doped zinc sulfide quantum dot is discussed in this study. Mn doped ZnS quantum dot surface passivated with capping agents such as L-histidine and also in polymers like chitosan, PVA and PVP were studied and compared. The tunable fluorescence effect was also observed in different polymers and amino acid as capping agents. Optical characterization studies like UV-Visible spectroscopy and PL spectroscopy have been carried out. The functional group modification of Quantum dot has been analyzed using FTIR and size and shape analysis was conducted by using HRTEM image. Result: The strong and broad peak of FTIR in the range of 3500-3300 cm-1 confirms the presence of O-H bond. It is also observed that quenching phenomena in the luminescent peak are due to weaker confinement effect. The average size of the particle is shown to be around 4-5 nm. Changes in color of the quantum dot solution from transparent to dark brown has been due to the interaction with dopamine. Conclusion: Finally, L-Histidine amino acid capped Mn:ZnS shows better results in luminescence and size confinement properties. Hence, it was chosen for dopamine sensing due to its colloidal nature and inborn affinity towards dopamine, a neurotransmitter which is essential for early diagnosis of neural diseases


Author(s):  
Frances S. Ligler ◽  
James W. Hazzard ◽  
Joel P. Golden ◽  
Chris A. Rowe

2021 ◽  
Author(s):  
Yan Zhang ◽  
Taisuke Kojima ◽  
Ge-Ah Kim ◽  
Monica P. McNerney ◽  
Shuichi Takayama ◽  
...  

AbstractSimultaneous detection of multiple analytes from a single sample (multiplexing), particularly when at the point of need, can guide complex decision-making without increasing the required sample volume or cost per test. Despite recent advances, multiplexing still typically faces the critical limitation of measuring only one type of molecule per assay platform – for example, only small molecules or only nucleic acids. In this work, we address this bottleneck with a customizable platform that integrates cell-free expression (CFE) with a polymer-based aqueous two-phase system (ATPS) to produce membrane-less “protocells” containing transcription and translation machinery used for analyte detection. Multiple protocells are arrayed in microwells where each protocell droplet performs distinct reactions to detect chemically diverse targets including small molecules, minerals, and nucleic acid sequences, all from the same sample. We demonstrate that these protocell arrays can measure analytes in a human biofluid matrix, maintain function after lyophilization and rehydration, and produce visually interpretable readouts, illustrating its potential for application as a minimal-equipment, field-deployable, multi-analyte detection tool.


Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 387 ◽  
Author(s):  
Caoxing Huang ◽  
Huiling Dong ◽  
Yan Su ◽  
Yan Wu ◽  
Robert Narron ◽  
...  

The carbon quantum dot (CQD), a fluorescent carbon nanoparticle, has attracted considerable interest due to its photoluminescent property and promising applications in cell imaging and bioimaging. In this work, biocompatible, photostable, and sustainably sourced CQDs were synthesized from byproducts derived from a biorefinery process using one-pot hydrothermal treatment. The main components of byproducts were the degradation products (autohydrolyzate) of biomass pretreated by autohydrolysis. The as-synthesized CQDs had a size distribution from 2.0–6.0 nm and had high percentage of sp2 and sp3 carbon groups. The CQDs showed blue-green fluorescence with a quantum yield of ~13%, and the fluorescence behaviors were found to be stable with strong resistance to photobleaching and temperature change. In addition, it is found that the as-synthesized CQDs could be used for imaging of cells and tumors, which show potential applications in bioimaging and related fields such as phototherapy and imaging.


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