Scientists have recently developed electrochemical immunosensors based on graphene oxide−gold (GO−Au) nanocomposites. These immunosensors are highly sensitive with dual function, i.e., they can detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen and antibody. This study is available in the journal ACS Applied Bio Materials.
Impact of Global Outbreak of Diseases
In the last century, the world has witnessed several global outbreaks that include influenza, severe acute respiratory syndrome coronavirus (SARS-CoV), middle east respiratory syndrome coronavirus (MERS), and most recently, SARS-CoV-2. The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2, has drastically impacted the global healthcare system and economy. To date, this virus has claimed more than 6.2 million lives and infected around 517 million individuals worldwide.
Scientists worldwide have worked extensively to develop effective preventive measures and sensitive diagnostic tools for fast and accurate detection of the SARS-CoV-2 virus. Early detection of the disease would help prevent further transmission of the virus in the community.
Diagnostic Tools for SARS-CoV-2
Although reverse transcriptase-polymerase chain reaction (RT-PCR) can accurately detect the SARS-CoV-2 virus by identifying viral genomic RNA, it requires expensive setups and highly skilled personnel for its operation. Scientists have stated serological-based methods, e.g., enzyme-linked immunosorbent assay (ELISA), for the detection of SARS-CoV-2 antibodies, are mind-numbing and time-consuming, which restricts their usage for mass testing for COVID-19 antibodies.
Previous studies have reported the development of biosensors, based on field-effect transistor (FET), electrochemical, and fluorescence, to detect COVID-19 disease. Electrochemical biosensors could be extremely advantageous over other biosensors because of their high sensitivity, accuracy, easy operation, and rapid detection processes. Scientists have stated that there is a need to develop superior electrochemical biosensors with greater transducing capabilities, applicability, and high active surface area.
Previous studies have shown that several nanomaterials and nanocomposites, for example, gold nanoparticles (AuNPs), graphene oxide (GO), and reduced graphene oxide (RGO), are promising constituents for novel electrochemical biosensors.
Development of Highly Sensitive Electrochemical Immunosensor for SARS-CoV-2: A New Study
Scientists have synthesized GO−Au nanocomposites to fabricate two immunosensors used to detect SARS-CoV-2 antigen and antibody. The newly developed GO−Au nanocomposites possess high conductivity, a large surface to area ratio, and several functional groups for their binding with biomolecules.
The authors have characterized the newly synthesized nanocomposites using UV−Vis spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The average particle size of the AuNPs in the nanocomposite was measured to be 12.1 nm. UV-Vis analysis revealed the presence of characteristic peaks of GO (265 nm) and Au (538 nm) in the synthesized GO-Au nanocomposite. Interestingly, XRD analysis showed a peak at 26.4°, which implied a partial reduction of GO in the nanocomposite. TEM image indicated a uniform dispersion of AuNPs in the nanocomposite as well as its polycrystalline nature.
The electrochemical activity of GO-Au nanocomposite and fabricated immunosensors were analyzed through differential pulse voltammetry (DPV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques. Scientists performed all electrochemical measurements in redox electrolytes.
CV helped determine SARS-CoV-2 antibody−antigen interaction on electrode surfaces. Both CV and DPV results revealed effective fabrication of the SARS-CoV-2 antibody immunosensor.
In this study, researchers reported that the SARS-CoV-2 antigen immunosensor exhibited excellent sensitivity with a linear detection range between 10.0 ag mL–1 and 50.0 ng mL–1. They further estimated the detection range of antibody immunosensor to be between 1.0 fg mL–1 and 1.0 ng mL–1. For the SARS-CoV-2 antibody immunosensor, the limit of detection (LOD) was measured to be 1 fg mL−1. Similarly, the LOD of the SARS-CoV-2 antigen immunosensor was estimated to be 3.99 ag mL−1.
Synthetic samples were used initially to analyze both the immunosensors and the results were later validated using serum and nasopharyngeal swab samples of COVID-19 patients. They obtained samples from nine different COVID-19 patients to validate their findings. Both DPV analysis and voltammetric characterization showed that the SARS-CoV-2 antibody immunosensor and SARS-CoV-2 antigen immunosensor could be effectively utilized to study clinical samples.
To further determine the sensitivity of the immunosensors, scientists used nasopharyngeal samples of seven different patients (four SARS-CoV-2 negatives and three positives). The results obtained in this study were consistent with the RT-PCR test.
Conclusion
In this study, the authors developed electrochemical immunosensor platforms based on newly developed GO−Au nanocomposites. These immunosensors have a dual function, i.e., detection of both SARS-CoV-2 antibodies as well as antigen. In the future, these immunosensors could be used to develop portable point of contact (POC) devices for accurate detection of the SARS-CoV-2 virus.
News
New material discovery could revolutionize roll-out of global vaccinations
New raw vaccine materials that could make vaccines more accessible, sustainable, and ethical have been discovered. The results of the research have been published in Polymers. Adjuvants are vaccine ingredients that boost a person's immune response [...]
Scientists Develop Incredibly Lightweight Material 4 Times Stronger Than Steel
Researchers developed a light yet strong material by combining two unexpected ingredients—DNA and glass. Working at the nanoscale provides scientists with a deep understanding and precision in crafting and analyzing materials. In broader-scale production, and even [...]
New Implant Doctors Hope Will Cut Cancer Deaths in Half
Researchers at Houston's Rice University are developing an implant that could diminish deaths caused by cancer by half. The device will contain synthetically nurtured human cells and be embedded with sensors to keep track of cancer [...]
Machine learning helps predict drugs’ favorite subcellular haunts
Most drugs are small molecules that bind firmly to a specific target—some molecule in human cells that is involved in a disease—in order to work. For example, a cancer drug's target might be a [...]
Nanotechnology Breakthrough Could Help Treat Blindness
Scientists utilize nanotechnology to address a prevalent cause of vision loss. Scientists have discovered a way to use nanotechnology to create a 3D ‘scaffold’ to grow cells from the retina. This breakthrough could lead [...]
Decoding Women’s Health: Artificial Intelligence Revolutionizes PCOS Diagnosis
NIH study reviews 25 years of data and finds AI/ML can detect common hormone disorder. Artificial intelligence (AI) and machine learning (ML) can effectively detect and diagnose Polycystic Ovary Syndrome (PCOS), which is the most common [...]
Surprising Discovery Could Explain How Coronaviruses Jump Species
New insights are enhancing scientists’ efforts to stay ahead of COVID-19 and the next pandemic. Unexpected new insights into the ways COVID-19 infects cells could shed light on the virus’s adept ability to jump from one species to another [...]
A blood test for long Covid is possible, a study suggests
Scientists can now show key differences in the blood of those who recover from Covid — and those who don't. More than three years into the pandemic, the millions of people who have suffered [...]
FedEx for your cells: this biological delivery service could treat disease
Researchers want to know why cells produce tiny packages called vesicles — and whether these bundles could be used for therapy. Graça Raposo was a young postdoc in the Netherlands in 1996 when she [...]
New study on the genetic magnetization of living bacteria shows great potential for biomedicine
Magnetic bacteria possess extraordinary capabilities due to the magnetic nanoparticles, the magnetosomes, which are concatenated inside their cells. A research team at the University of Bayreuth has now transferred all of the approximately 30 [...]
Ultrathin Nanotech Promises to Help Tackle Antibiotic Resistance
Researchers have invented a nano-thin superbug-slaying material that could one day be integrated into wound dressings and implants to prevent or heal bacterial infections. The innovation – which has undergone advanced pre-clinical trials – [...]
Researchers Discover New Mnemomic Networks in the Brain
The medial temporal lobe (MTL) houses the human memory system. Broadly, it contains the hippocampus, parahippocampal cortex, perirhinal cortex, and entorhinal cortex. “One big challenge in studying the MTL is its great anatomical variability [...]
The Surprising Origin of a Deadly Hospital Infection
C. diff might not originate from external transmission but rather from within the infected patient themselves. Hospital staff dedicate significant effort to safeguard patients from infections during their hospital stay. Through practices ranging from [...]
Google AI breakthrough – huge step in finding genes that cause diseases
Google says it has made a significant step in identifying disease-causing genes, which could help spot rare genetic disorders. A new model named AlphaMissense is able to confidently classify 89 per cent of all [...]
New Study: Everyday Pleasures Can Boost Cognitive Performance
MINDWATCH study reveals cognitive peaks with everyday pleasures. Listening to music and drinking coffee are the sorts of everyday pleasures that can impact a person’s brain activity in ways that improve cognitive performance, including [...]
Moderna reveals new highly targeted COVID-19 vaccine mRNA-1283
Moderna has developed a new and improved version of its COVID-19 vaccine. The unique formulation (mRNA-1283) reduces the vaccine's content from the full-length SARS-CoV-2 spike protein to a narrowly focused encoding of just two [...]
