This detection method uses plasmonic photothermal effect and localized surface plasmon resonance. It could be a faster and cheaper alternative to RT-PCR method. Au nanomaterials are used to sense hybridized cDNAs of the virus.

Dual-Functional Plasmonic Biosensor

"a FET sensor (modified with graphene sheets) that uses a specific antibody against SARS-CoV-2 spike protein was reported to detect SARS-CoV-2 in culture medium
(limit of detection, LOD: 1.6 × 101 pfu/mL) and clinical samples (LOD: 2.42 × 102 copies/mL)"

Graphene-based Field-Effect Transistor (FET) Biosensor

Affinity capture magnetic hydrogel particles can be used to capture SARS-CoV-2 from the saliva of a person who is being tested for the virus. In this method the virus is concentrated before the extraction of RNA occurs. Transport medium diagnostic remnant samples that have been tested before using previous methods help show that the method correctly identifies positive samples as well as improves the likelihood of detecting the virus in samples that contain a low percentage of COVID-19 positive patients. 

Nanotrap Particles 

The relationship between the gut microbiome and COVID-19 may be exploited as a diagnostic tool using nanotechnology in a variety of ways:
- Non-invasive breath tests: to “identify volatile organic compounds with the signatures of modulated microbiota”, allowing for detection of SARS-CoV-2. 
- Ingestible sensors: to detect inflammatory proteins associated with COVID-19 

Possible Gut Microbiome Nanotechnology for COVID-19 Diagnosis

Combining the excellent electrical and optical properties of nanomaterials with biological or synthetic molecules as receptors to detect selectively any kind of analyte, nanobiosensors are a valuable alternative to conventional diagnostic tools. 

- Graphene-based Field-Effect Transistor (FET) Biosensor

- Dual-Functional Plasmonic Biosensor

Paper/nanomaterial-based sensors, in general, and, particularly, NP-based lateral-flow devices that are observed with the naked eye or operated through a smartphone are now the most reported testing platforms for the analysis of COVID-19-related biomarkers. Nanopaper and nanochannels may also offer cost-efficient alternatives for detection of viruses and related biomarkers. 

Smith College

Nanomaterials have versatile applications, including but not limited to the following areas: 


- Nanomaterials for COVID-19 Combined Diagnosis and Therapy 

- Nanomaterials for COVID-19 Diagnosis 

- Nanomaterials for COVID-19 Treatment

- Nanomaterials for Personal Protective Equipment (PPE) 









Nanomaterials for COVID-19

Biosensors for COVID-19

- Isothermal Nucleic Acid Amplification
- RPA
- CRISPR
- Cas13a Assay
- Next Generation Sequencing 
- Nanomaterials (nanotrap particles, etc.)
- Wondfo Qualitative Rapid Chromatographic Immunoassay (RCI)

Emerging Methods for Diagnosis of SARS-CoV-2

Weiss C, Carriere M, Fusco L, et al. Toward Nanotechnology-Enabled Approaches against the COVID-19 Pandemic. ACS Nano. 2020;14(6):6383-6406. doi:10.1021/acsnano.0c03697

Toward Nanotechnology-Enabled Approaches against the COVID-19 Pandemic

Nanomaterials can be used to increase the performance and safety of PPE, such as air filters and masks. They may be used to not only capture aerosol droplets but also inactivate the virus upon contact with the surfaces of PPE. 

Opportunities for nanotechnology-based solutions to increase the efficiency and safety of air filter and mask devices include (i) improving particle capture and retention characteristics, particularly, in the 300 nm diameter size range; (ii) reducing the effects of exhaled humid air on particle redistribution; (iii) rapid inactivation of membrane-bound microbes including enveloped viruses upon capture; and (iv) thin, high-efficiency filtration media for personal masks that are able to be reused repeatedly without loss of efficiency (e.g., novel electrospun nanofibers). 


Nanomaterials for Personal Protective Equipment (PPE)

- Photodynamic Inactivation of SARS-CoV-2 with Nanomaterials
- Photothermal Inactivation of SARS-CoV-2 with Nanomaterials
- Inactivation of SARS-CoV-2 with Photocatalytic Nanomaterials
- Other Methods of SARS-CoV-2 Inactivation with Nanomaterials
- Nanomaterial-based Immune Modulation for SARS-CoV-2
- Nanomaterial-based Drug Delivery Systems for SARS-CoV-2
- Nanotechnology to target gut microbiome

Nanomaterials for COVID-19 Treatment 

Nanomaterials for COVID-19 Diagnosis

Islam, M. M., Mahmud, S., Muhammad, L. J., Islam, M. R., Nooruddin, S., & Ayon, S. I. (2020). Wearable Technology to Assist the Patients Infected with Novel Coronavirus (COVID-19). SN computer science, 1(6), 320. https://doi.org/10.1007/s42979-020-00335-4

Wearable Technology to Assist the Patients Infected with Novel Coronavirus (COVID-19)


Existing wearable monitoring devices:
- respiration rate
- heart rate
- temperature
- oxygen saturation 
Respiratory support systems:
- ventilators
- CPAP devices
- oxygen therapy

Existing medical devices for COVID-19

The development of a SENsitive Splint-based one-step isothermal RNA detection (SENSR) method for rapid and straightforward onsite detection of pathogen RNAs with high sensitivity and specificity offers great potential for SARS-CoV-2 diagnosis. 


SENSR consists of two simple enzymatic reactions: a ligation reaction by SplintR ligase and subsequent transcription by T7 RNA polymerase. The resulting transcript forms an RNA aptamer that induces fluorescence. Compared to the conventional culture-based or immunoassay-based approaches, a nucleic acid-based approach relies primarily on a strand-displacing polymerase or T7 RNA polymerase at a constant temperature. In particular, the SplintR ligase can efficiently ligate two DNA probes using a target single-stranded RNA as a splint, enabling the sequence-specific detection of RNA molecules. 


SENSR integrates all component reaction steps using the specially designed probes that contain all required functional parts: promoter, hybridization sequence to target, and an aptamer template. Even with the multifaceted features of the SENSR probes, the design process is systematic and straightforward. The probe design is unique in that two DNA probes are designed to expose single-stranded target recognition parts, enabling hybridization of the target RNA and the probes at 37°C. 


SENsitive Splint-based one-step isothermal RNA detection (SENSR)

This method amplifies a DNA or RNA target sequence, but unlike PCR, does not need thermal cycling. These assays use isothermal methods to allow for primer binding and then amplify the selected strands using a polymerase with stand displacement activity. The amplified gene products are then detected via photometry. 

Isothermal Nucleic Acid Amplification

This method detects the total viral RNA from a cell culture supernatant and 19 nasopharyngeal swab samples. Uses isothermal methods for reverse transcription and then uses recombinase activity to promote primer binding to the respective dsDNA sequence. This process also achieves 100% specificity and sensitivity and offers advantages over the typical RT-PCR in efficiency and portability allowing for clinical decisions to be made real time when a patient visits. 

Uses recently discovered crRNA guided detection that is specific to viral RNA. The Cas13a enzyme that recognizes and binds targeted RNAs in a sequence-specific manner for signal amplification and nucleic acid detection.   

CRISPR

Unlike CRISPR, the Cas13a protein needs to be purified and is recombinantly expressed. Target site-recognition activates reporter probes resulting in fluorescence to recognize viral RNA. Assays can be designed as a paper dipstick test which delivers in 30-60 minutes. 


Cas13a Assay

NGS can sequence 30,000 nucleotides of the viral genome. This method provides insight on environmental monitoring, surveillance testing, and origin of the strain to pinpoint the viral evolution. 

Next Generation Sequencing

Diagnostic Testing methods that amplify DNA using reverse transcriptase.
Nucleic Acid Amplification Tests include but are not limited to:

- RT-PCR
- RT-LAMP
- Next Generation Sequencing
- Isothermal Nucleic Acid Amplification
- RPA

NAAT

The Wondfo RCI functions by detecting IgM/IgG antibodies for SARS-CoV-2.  10 μL of plasma or serum are inserted into the testing device, and antibodies that fight against SARS-CoV-2 contained in the sample attach to recombinant antigens that cover colloidal gold particles, ultimately creating a complex of antigen-antibody/colloidal gold particles.  80 μL of buffer solution must also be inserted into the testing device under the sample cavity.  The results of the RCI can be read within 15 minutes.  A major limitation of RCI is that it is not capable of differentiating between acute disease and infection from the past.  


Learn Before

Related

Learn After