Nanotechnology Full Text

Journal of Applied Nanotechnology

Nanodiagnostics: A savior in COVID-19 pandemic

Vivek Borse1*ORCID ID

1NanoBioSens Lab, Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India.

*Corresponding Author: Borse V, NanoBioSens Lab, Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam, India. E-mail:

Citation: Borse V. Nanodiagnostics: A savior in COVID-19 pandemic. Journal of Applied Nanotechnology. 2021;1(1):1-4.

Copyright: © 2021 Borse V. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Received On: 30th December,2020   Accepted On: 18th January,2021   Published On: 25th January,2021

Letter to the Editor

A year has passed since the first case of COVID-19 was reported. Since then, it has been wreaking havoc all around the world and changing the course of routine human activities. SARS-CoV-2 that belongs to the genus Betacoronavirus [1], is the cause of the COVID-19 outbreak. The virus invades the cells rich in angiotensin-converting enzyme 2 (ACE2) receptor. Most of the human organs possess the ACE2 protein but it is abundant in the epithelial cells of lung alveoli and small intestine [2]. In most cases, the disease results in mild to moderate symptoms like dry cough, fever, and dyspnoea but in severe cases may lead to extreme breathing difficulties and septic shock. As of 18 January 2021, the World Health Organization (WHO) has reported 95.4 million confirmed cases with 2 million deaths globally. Although several vaccine candidates are in the process of development or are getting approved for use, detection and diagnosis of the disease followed by isolation of the diseased individual will remain the primary way to stop the spread of the disease for some time. Therefore, the ongoing COVID-19 pandemic has created an urgency for the development of innovative techniques for the rapid detection of novel coronavirus (2019-nCoV). Various diagnostic techniques have been developed by different researchers across the globe. COVID-19 tests are performed based on the detection of the virus genetic material or protein [3]. Both conventional and novel diagnostic techniques are being used for viral detection, including different novel nanotechnology-based diagnostic devices that help in the rapid and early detection of COVID-19 [4-8]. These devices have shown several advantages over other conventional devices for infectious disease diagnosis in the past as well. Similarly, nanodiagnostics continues to play an important role in COVID-19 diagnosis as well.

Nanodiagnostic has gained much attention in the field of medical diagnosis. The advantages of nanodiagnostic techniques outweigh the disadvantages because of their rapid diagnosis, lower detection limit, high sensitivity, and specificity. For architecting nanobiosensors-based devices different sub-microscopic nanoparticles (e.g., gold nanoparticles, silver nanoparticles, quantum dots, carbon nanoparticles) may be utilized that strengthen the accuracy rate of the diagnostic devices [9-14]. The sensitivity and specificity of these diagnostic devices are due to the interaction between biological molecules and sub-microscopic nanoparticles. Depending on the nature of the interaction, the nanobiosensors are divided into affinity biosensors and catalytic biosensors. Protein biosensors, aptamers-based biosensors, and nucleic acid biosensors are affinity-based biosensors. Enzymatic biosensors come under catalytic biosensors. The transducer utilized within the biosensor measures the signal produced after the interaction. So, based on the nature of the transducer used, biosensors are often listed as labeled biosensors and labeled-free biosensors [11]. Optical biosensors and electrochemical biosensors are the two widely used types of biosensors in nanodiagnostic applications. Many optical-based lateral flow immunoassays are used as point-of-care (POC) devices for the detection of several diseases [15].

Reverse-transcription polymerase chain reaction (RT-PCR) has been highly preferred to detect the genetic material of SARS-CoV-2 [16]. But this technique requires a longer time and skilled technicians for analysis. To beat the restrictions of RT-PCR, one step amplification process i.e., loop-mediated isothermal amplification (LAMP) was introduced for COVID-19 detection [17]. RT-LAMP is reported as a more rapid and easier diagnostic procedure than the RT-PCR method. A diagnostic technique was developed by combining lateral flow immunoassays (LFIAs) and RT-LAMP. Here, LFIAs clarify the results of RT-LAMP that enhance the specificity of the assay [18]. Surface plasmon resonance phenomenon of gold nanoparticles (i.e., two-dimensional gold nanoislands) and plasmonic photothermal effect (PPT) has been used for COVID-19 diagnosis. The DNA probes on the gold nanoislands chip recognize the target sequences of SARS-CoV-2 RNA through hybridization reaction. PPT heating increases the precision of the hybridization process [19].

Another target site for the detection of SARS-CoV-2 is its surface antigens. In humans, the protruding spike glycoproteins (S protein) of the virus bind with the host receptors (i.e., ACE2 protein) and then infect the host cells. The interaction between the viral and host proteins provokes the host immune system to develop different antibodies (i.e., IgM, IgA, IgG) [20]. Therefore, the detection of both antigens and antibodies is important to confirm the infection. IgM production remains high during the first stage of SARS-CoV-2 infection, followed by immunoglobulin G [20]. Based on the interaction of antigen and antibody, several nanoparticle-based lateral flow test kits are made available in the market by different companies for rapid detection of COVID-19 [21]. Using S protein against specific antibody SARS-CoV-2, a novel graphene-field effect transistor-based biosensor was designed. The detection process depends on the change in electric current when the surface antigen binds with the antibody attached to graphene sheets [22]. Scientist suggests facilitation of graphene-field effect transistor-based biosensor for COVID-19 antibody testing [23]. The grating-couple fluorescent plasmonic (GC-FP) assay is a new nanodiagnostic technique for antibody testing. Gold nanoparticles (AuNPs) containing GC-FP chip was constructed where different antigens of COVID-19 were imprinted to detect the multiple antibodies present in human blood samples [24]. Recently, two novel nanobiosensor based diagnostic devices have been designed for quick identification of spike antigen. In the portable immunosensor device “eCovSens”, AuNPs were layered on top of a fluorine tin oxide electrode. SARS-CoV-2 antibody linked with AuNPs captures the viral antigen [25]. The change in the electric signal confirms the presence of spike protein in the collected saliva sample. The second device, a cell-based biosensor completes the detection within 3 mins. This fast diagnostic tool involves “membrane-engineered cell” and “human chimeric antibody” to detect the spike S1 protein [26].

Different laboratories, companies, and universities across the world have been working to develop novel techniques to fight the COVID-19 pandemic. The reported nanodiagnostic devices developed by different scientists across the globe are some of the most sensitive and specific diagnostic devices that can help in the rapid detection of the disease. Improvisation is still necessary to achieve advancement in nanobiosensor based devices to eliminate their drawbacks such as toxicity and chemical instability of nanoparticles, low quantitative analysis of optical-based biosensors, and use of extra equipment in electrochemical biosensors that hinders its miniaturization [11]. New nanotechnology and microfluidic-based devices are being developed that also integrated the use of smartphones and lab-on-chip technology within the field of clinical diagnosis [27, 28]. However, commercialization of the novel diagnostic devices is needed for the first-line healthcare system.

Countries with huge populations are the worst affected because of COVID-19. This is mainly because of deficiency of rapid diagnostic test devices for early disease detection. There is a growing need for rapid, cost-effective, highly sensitive, and specific commercial diagnostic devices for the early detection of SARS-CoV-2. Research institutions are focusing on the development of cost-effective POC diagnostic devices for quick response to manage the present pandemic and prevent any forthcoming pandemic. Nanobiotechnology-based diagnostic techniques have shifted the paradigm to tackle the COVID-19. Numerous nanodiagnostics technologies are already in practice and others have enormous potential for future applications in controlling COVID-19 pandemic.


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