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1.
ACS Appl Mater Interfaces ; 13(34): 40342-40353, 2021 Sep 01.
Article in English | MEDLINE | ID: covidwho-1366784

ABSTRACT

Sensitive point-of-care methods for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in clinical specimens are urgently needed to achieve rapid screening of viral infection. We developed a magnetic quantum dot-based dual-mode lateral flow immunoassay (LFIA) biosensor for the high-sensitivity simultaneous detection of SARS-CoV-2 spike (S) and nucleocapsid protein (NP) antigens, which is beneficial for improving the detection accuracy and efficiency of SARS-CoV-2 infection in the point-of-care testing area. A high-performance magnetic quantum dot with a triple-QD shell (MagTQD) nanotag was first fabricated and integrated into the LFIA system to provide superior fluorescence signals, enrichment ability, and detectability for S/NP antigen testing. Two detection modes were provided by the proposed MagTQD-LFIA. The direct mode was used for rapid screening or urgent detection of suspected samples within 10 min, and the enrichment mode was used for the highly sensitive and quantitative analysis of SARS-CoV-2 antigens in biological samples without the interference of the "hook effect." The simultaneous detection of SARS-CoV-2 S/NP antigens was conducted in one LFIA strip, and the detection limits for two antigens under direct and enrichment modes were 1 and 0.5 pg/mL, respectively. The MagTQD-LFIA showed high accuracy, specificity, and stability in saliva and nasal swab samples and is an efficient tool with flexibility to meet the testing requirements for SARS-CoV-2 antigens in various situations.


Subject(s)
Antigens, Viral/analysis , Biosensing Techniques/methods , Coronavirus Nucleocapsid Proteins/analysis , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/analysis , Antibodies, Immobilized/immunology , Antibodies, Monoclonal/immunology , Antigens, Viral/immunology , Coronavirus Nucleocapsid Proteins/immunology , Fluorescence , Fluorescent Dyes/chemistry , Humans , Immunoassay/methods , Limit of Detection , Magnetite Nanoparticles/chemistry , Nasopharynx/virology , Phosphoproteins/analysis , Phosphoproteins/immunology , Quantum Dots/chemistry , Saliva/virology , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus/immunology
2.
ACS Appl Mater Interfaces ; 13(7): 7966-7976, 2021 Feb 24.
Article in English | MEDLINE | ID: covidwho-1075146

ABSTRACT

Nowadays, there is an increasing demand for more accessible routine diagnostics for patients with respect to high accuracy, ease of use, and low cost. However, the quantitative and high accuracy bioassays in large hospitals and laboratories usually require trained technicians and equipment that is both bulky and expensive. In addition, the multistep bioassays and long turnaround time could severely affect the disease surveillance and control especially in pandemics such as influenza and COVID-19. In view of this, a portable, quantitative bioassay device will be valuable in regions with scarce medical resources and help relieve burden on local healthcare systems. Herein, we introduce the MagiCoil diagnostic device, an inexpensive, portable, quantitative, and rapid bioassay platform based on the magnetic particle spectrometer (MPS) technique. MPS detects the dynamic magnetic responses of magnetic nanoparticles (MNPs) and uses the harmonics from oscillating MNPs as metrics for sensitive and quantitative bioassays. This device does not require trained technicians to operate and employs a fully automatic, one-step, and wash-free assay with a user friendly smartphone interface. Using a streptavidin-biotin binding system as a model, we show that the detection limit of the current portable device for streptavidin is 64 nM (equal to 5.12 pmole). In addition, this MPS technique is very versatile and allows for the detection of different diseases just by changing the surface modifications on MNPs. Although MPS-based bioassays show high sensitivities as reported in many literatures, at the current stage, this portable device faces insufficient sensitivity and needs further improvements. It is foreseen that this kind of portable device can transform the multistep, laboratory-based bioassays to one-step field testing in nonclinical settings such as schools, homes, offices, etc.


Subject(s)
Biological Assay , Magnetite Nanoparticles/chemistry , Smartphone , Streptavidin/analysis , Biological Assay/instrumentation , COVID-19/diagnosis , Humans , Hydrodynamics , Influenza, Human/diagnosis , Magnetic Phenomena , Particle Size , Surface Properties
3.
ACS Sens ; 6(3): 976-984, 2021 03 26.
Article in English | MEDLINE | ID: covidwho-1047925

ABSTRACT

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global medical systems and economies and rules our daily living life. Controlling the outbreak of SARS-CoV-2 has become one of the most important and urgent strategies throughout the whole world. As of October 2020, there have not yet been any medicines or therapies to be effective against SARS-CoV-2. Thus, rapid and sensitive diagnostics is the most important measures to control the outbreak of SARS-CoV-2. Homogeneous biosensing based on magnetic nanoparticles (MNPs) is one of the most promising approaches for rapid and highly sensitive detection of biomolecules. This paper proposes an approach for rapid and sensitive detection of SARS-CoV-2 with functionalized MNPs via the measurement of their magnetic response in an ac magnetic field. For proof of concept, mimic SARS-CoV-2 consisting of spike proteins and polystyrene beads are used for experiments. Experimental results demonstrate that the proposed approach allows the rapid detection of mimic SARS-CoV-2 with a limit of detection of 0.084 nM (5.9 fmole). The proposed approach has great potential for designing a low-cost and point-of-care device for rapid and sensitive diagnostics of SARS-CoV-2.


Subject(s)
Antibodies, Monoclonal/chemistry , Magnetite Nanoparticles/chemistry , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Antibodies, Monoclonal/immunology , Biosensing Techniques , Magnetic Phenomena , Polystyrenes/chemistry , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology
4.
Talanta ; 225: 121977, 2021 Apr 01.
Article in English | MEDLINE | ID: covidwho-1003086

ABSTRACT

SARS-COV-2 is a novel coronavirus discovered in Wuhan in December 30, 2019, and is a family of SARS-COV (severe acute respiratory syndrome coronavirus), that is, coronavirus family. After infection with SARS-COV-2, patients often experience fever, cough, gas prostration, dyspnea and other symptoms, which can lead to severe acute respiratory syndrome (SARS), kidney failure and even death. The SARS-COV-2 virus is particularly infectious and has led to a global infection crisis, with an explosion in the number of infections. Therefore, rapid and accurate detection of the virus plays a vital role. At present, many detection methods are limited in their wide application due to their defects such as high preparation cost, poor stability and complex operation process. Moreover, some methods need to be operated by professional medical staff, which can easily lead to infection. In order to overcome these problems, a Surface molecular imprinting technology (SM-MIT) is proposed for the first time to detect SARS-COV-2 virus. For this SM-MIT method, this review provides detailed detection principles and steps. In addition, this method not only has the advantages of low cost, high stability and good specificity, but also can detect whether it is infected at designated points. Therefore, we think SM-MIT may have great potential in the detection of SARS-COV-2 virus.


Subject(s)
COVID-19/diagnosis , Magnetite Nanoparticles/chemistry , Molecular Imprinting , Polymers/chemistry , SARS-CoV-2/metabolism , Viral Proteins/metabolism , COVID-19/virology , Humans , Microspheres , Ovalbumin/chemistry , Ovalbumin/metabolism , SARS-CoV-2/physiology , Sensitivity and Specificity , Viral Proteins/chemistry
5.
Sci Rep ; 10(1): 19004, 2020 11 04.
Article in English | MEDLINE | ID: covidwho-910351

ABSTRACT

Ecuador is one of the most affected countries, with the coronavirus disease 2019 (COVID-19) infection, in Latin America derived from an ongoing economic crisis. One of the most important methods for COVID-19 detection is the use of techniques such as real time RT-PCR based on a previous extraction/purification of RNA procedure from nasopharyngeal cells using functionalized magnetic nanoparticles (MNP). This technique allows the processing of ~ 10,000 tests per day in private companies and around hundreds per day at local Universities guaranteeing to reach a wide range of the population. However, the main drawback of this method is the need for specialized MNP with a strong negative charge for the viral RNA extraction to detect the existence of the SARS-CoV-2 virus. Here we present a simplified low cost method to produce 10 g of nanoparticles in 100 mL of solution that was scaled to one litter by parallelizing the process 10 times in just two days and allowing for the possibility of making ~ 50,000 COVID-19 tests. This communication helps in reducing the cost of acquiring MNP for diverse biomolecular applications supporting developing country budgets constraints and chemical availability specially during the COVID-19 International Health Emergency.


Subject(s)
Clinical Laboratory Techniques/methods , Costs and Cost Analysis , Magnetite Nanoparticles/chemistry , Reverse Transcriptase Polymerase Chain Reaction/methods , COVID-19 Testing , COVID-19 Vaccines , Coronavirus Infections/diagnosis , Developing Countries , Humans , Magnetite Nanoparticles/economics , RNA, Viral/chemistry , Reverse Transcriptase Polymerase Chain Reaction/economics
6.
Biosens Bioelectron ; 165: 112356, 2020 Oct 01.
Article in English | MEDLINE | ID: covidwho-505616

ABSTRACT

Circle-to-circle amplification (C2CA) is a specific and precise cascade nucleic acid amplification method consisting of more than one round of padlock probe ligation and rolling circle amplification (RCA). Although C2CA provides a high amplification efficiency with a negligible increase of false-positive risk, it contains several step-by-step operation processes. We herein demonstrate a homogeneous and isothermal nucleic acid quantification strategy based on C2CA and optomagnetic analysis of magnetic nanoparticle (MNP) assembly. The proposed homogeneous circle-to-circle amplification eliminates the need for additional monomerization and ligation steps after the first round of RCA, and combines two amplification rounds in a one-pot reaction. The second round of RCA produces amplicon coils that anneal to detection probes grafted onto MNPs, resulting in MNP assembly that can be detected in real-time using an optomagnetic sensor. The proposed methodology was applied for the detection of a synthetic complementary DNA of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2, also known as 2019-nCoV) RdRp (RNA-dependent RNA polymerase) coding sequence, achieving a detection limit of 0.4 fM with a dynamic detection range of 3 orders of magnitude and a total assay time of ca. 100 min. A mathematical model was set up and validated to predict the assay performance. Moreover, the proposed method was specific to distinguish SARS-CoV and SARS-CoV-2 sequences with high similarity.


Subject(s)
Betacoronavirus/isolation & purification , Biosensing Techniques/instrumentation , Coronavirus Infections/diagnosis , DNA, Complementary/analysis , Nucleic Acid Amplification Techniques/instrumentation , Pneumonia, Viral/diagnosis , Biosensing Techniques/methods , COVID-19 , Equipment Design , Feasibility Studies , Humans , Limit of Detection , Magnetics/instrumentation , Magnetics/methods , Magnetite Nanoparticles/chemistry , Nucleic Acid Amplification Techniques/methods , Pandemics , SARS-CoV-2
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