Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 380
Filter
Add filters

Document Type
Year range
1.
Biosens Bioelectron ; 196: 113701, 2022 Jan 15.
Article in English | MEDLINE | ID: covidwho-1638371

ABSTRACT

Although CRISPR-Cas12a and CRISPR-Cas13a systems work individually effective on gene detection, their multiplex detection capability is limited due to the lack of specific probe cleavage mechanism. Herein we present a high-efficient dual-gene diagnostic technique based on the orthogonal DNA/RNA collateral cleavage mechanism of Cas12a/Cas13a system. In this design, dual-gene amplified products from the multiplex recombinase polymerase amplification (RPA) were simultaneously detected by Cas12a and Cas13a assay in a single tube. The resulting orthogonal DNA/RNA collateral cleavage can specifically illuminate two spectral differentiated DNA and RNA probes, respectively. By integrating with the smartphone-based fluorescence readout, a portable detection platform is achieved. As a proof-of-concept, reliable dual-gene detection of SARS-CoV-2 and African Swine fever virus (ASFV) were demonstrated, exhibiting 100% sensitivity and specificity for clinical samples analysis (32 swab specimens for SARS-CoV-2 and 35 ASFV suspected swine blood samples). This developed portable dual-gene detection platform can provide accurate point-of-care screening of infectious diseases in resources-limited settings.


Subject(s)
African Swine Fever Virus , Biosensing Techniques , COVID-19 , Animals , CRISPR-Cas Systems/genetics , Humans , SARS-CoV-2 , Swine
2.
Sensors (Basel) ; 22(2)2022 Jan 12.
Article in English | MEDLINE | ID: covidwho-1632064

ABSTRACT

A graphene oxide (GO)-based cortisol biosensor was developed to accurately detect cortisol concentrations from sweat samples at point-of-care (POC) sites. A reference electrode, counter electrode, and working electrode make up the biosensor, and the working electrode was functionalized using multiple layers consisting of GO and antibodies, including Protein A, IgG, and anti-Cab. Sweat samples contact the anti-Cab antibodies to transport electrons to the electrode, resulting in an electrochemical current response. The sensor was tested at each additional functionalization layer and at cortisol concentrations between 0.1 and 150 ng/mL to determine how the current response differed. A potentiostat galvanostat device was used to measure and quantify the electrochemical response in the GO-based biosensor. In both tests, the electrochemical responses were reduced in magnitude with the addition of antibody layers and with increased cortisol concentrations. The proposed cortisol biosensor has increased accuracy with each additional functionalization layer, and the proposed device has the capability to accurately measure cortisol concentrations for diagnostic purposes.


Subject(s)
Biosensing Techniques , Graphite , Biomarkers , Electrochemical Techniques , Electrodes
3.
PLoS One ; 16(12): e0260894, 2021.
Article in English | MEDLINE | ID: covidwho-1623649

ABSTRACT

BACKGROUND: Performance of the SD Biosensor saliva antigen rapid test was evaluated at a large designated testing site in non-hospitalized patients, with or without symptoms. METHOD: All eligible people over 18 years of age presenting for a booked appointment at the designated SARS-CoV-2 testing site were approached for inclusion and enrolled following verbal informed consent. One nasopharyngeal swab was taken to carry out the default antigen rapid test from which the results were reported back to the patient and one saliva sample was self-taken according to verbal instruction on site. This was used for the saliva antigen rapid test, the RT-PCR and for virus culture. Sensitivity of the saliva antigen rapid test was analyzed in two ways: i, compared to saliva RT-PCR; and ii, compared to virus culture of the saliva samples. Study participants were also asked to fill in a short questionnaire stating age, sex, date of symptom onset. Recommended time of ≥30mins since last meal, drink or cigarette if applicable was also recorded. The study was carried out in February-March 2021 for 4 weeks. RESULTS: We could include 789 people with complete records and results. Compared to saliva RT-PCR, overall sensitivity and specificity of the saliva antigen rapid test was 66.1% and 99.6% which increased to 88.6% with Ct ≤30 cutoff. Analysis by days post onset did not result in higher sensitivities because the large majority of people were in the very early phase of disease ie <3 days post onset. When breaking down the data for symptomatic and asymptomatic individuals, sensitivity ranged from 69.2% to 50% respectively, however the total number of RT-PCR positive asymptomatic participants was very low (n = 5). Importantly, almost all culture positive samples were detected by the rapid test. CONCLUSION: Overall, the potential benefits of saliva antigen rapid test, could outweigh the lower sensitivity compared to nasopharyngeal antigen rapid test in a comprehensive testing strategy, especially for home/self-testing and in vulnerable populations like elderly, disabled or children where in intrusive testing is either not possible or causes unnecessary stress.


Subject(s)
Biosensing Techniques/methods , COVID-19 Serological Testing/methods , Saliva/virology , Adolescent , Adult , Aged , COVID-19/diagnosis , COVID-19/etiology , Carrier State/virology , Female , Hospitalization , Humans , Male , Middle Aged , Nasopharynx/virology , Sensitivity and Specificity , Young Adult
4.
Nat Commun ; 13(1): 72, 2022 01 10.
Article in English | MEDLINE | ID: covidwho-1616984

ABSTRACT

The use of facemasks by the general population is recommended worldwide to prevent the spread of SARS-CoV-2. Despite the evidence in favour of facemasks to reduce community transmission, there is also agreement on the potential adverse effects of their prolonged usage, mainly caused by CO2 rebreathing. Herein we report the development of a sensing platform for gaseous CO2 real-time determination inside FFP2 facemasks. The system consists of an opto-chemical sensor combined with a flexible, battery-less, near-field-enabled tag with resolution and limit of detection of 103 and 140 ppm respectively, and sensor lifetime of 8 h, which is comparable with recommended FFP2 facemask usage times. We include a custom smartphone application for wireless powering, data processing, alert management, results displaying and sharing. Through performance tests during daily activity and exercise monitoring, we demonstrate its utility for non-invasive, wearable health assessment and its potential applicability for preclinical research and diagnostics.


Subject(s)
Biosensing Techniques/instrumentation , COVID-19/prevention & control , Carbon Dioxide/analysis , Masks , Personal Protective Equipment , Wearable Electronic Devices , Biosensing Techniques/methods , COVID-19/transmission , COVID-19/virology , Equipment Design , Humans , Reproducibility of Results , SARS-CoV-2/physiology
5.
ACS Appl Mater Interfaces ; 14(2): 2522-2533, 2022 Jan 19.
Article in English | MEDLINE | ID: covidwho-1606881

ABSTRACT

Electrochemical detection in complex biofluids is a long-standing challenge as electrode biofouling hampers its sensing performance and commercial translation. To overcome this drawback, pyrolyzed paper as porous electrode coupled with the drop casting of an off-the-shelf polysorbate, that is, Tween 20 (T20), is described here by taking advantage of the in situ formation of a hydrophilic nanocoating (2 nm layer of T20). The latter prevents biofouling while providing the capillarity of samples through paper pores, leveraging redox reactions across both only partially fouled and fresh electrodic surfaces with increasing detection areas. The nanometric thickness of this blocking layer is also essential by not significantly impairing the electron-transfer kinetics. These phenomena behave synergistically to enhance the sensibility that further increases over long-term exposures (4 h) in biological fluids. While the state-of-the-art antibiofouling strategies compromise the sensibility, this approach leads to peak currents that are up to 12.5-fold higher than the original currents after 1 h exposure to unprocessed human plasma. Label-free impedimetric immunoassays through modular bioconjugation by directly anchoring spike protein on gold nanoparticles are also allowed, as demonstrated for the COVID-19 screening of patient sera. The scalability and simplicity of the platform combined with its unique ability to operate in biofluids with enhanced sensibility provide the generation of promising biosensing technologies toward real-world applications in point-of-care diagnostics, mass testing, and in-home monitoring of chronic diseases.


Subject(s)
Antibodies, Viral/immunology , Biosensing Techniques/methods , COVID-19 Serological Testing/methods , Diagnostic Tests, Routine/methods , Recombinant Proteins/immunology , Spike Glycoprotein, Coronavirus/immunology , Early Diagnosis , Humans , Sensitivity and Specificity
6.
Sensors (Basel) ; 21(24)2021 Dec 20.
Article in English | MEDLINE | ID: covidwho-1594848

ABSTRACT

Cytokines are proteins secreted by immune cells. They promote cell signal transduction and are involved in cell replication, death, and recovery. Cytokines are immune modulators, but their excessive secretion causes uncontrolled inflammation that attacks normal cells. Considering the properties of cytokines, monitoring the secretion of cytokines in vivo is of great value for medical and biological research. In this review, we offer a report on recent studies for cytokine detection, especially studies on aptasensors using aptamers. Aptamers are single strand nucleic acids that form a stable three-dimensional structure and have been receiving attention due to various characteristics such as simple production methods, low molecular weight, and ease of modification while performing a physiological role similar to antibodies.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Cytokines
7.
Anal Chem ; 94(2): 975-984, 2022 01 18.
Article in English | MEDLINE | ID: covidwho-1592056

ABSTRACT

Serological tests are essential for the control and management of COVID-19 pandemic (diagnostics and surveillance, and epidemiological and immunity studies). We introduce a direct serological biosensor assay employing proprietary technology based on plasmonics, which offers rapid (<15 min) identification and quantification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in clinical samples, without signal amplification. The portable plasmonic device employs a custom-designed multiantigen (RBD peptide and N protein) sensor biochip and reaches detection limits in the low ng mL-1 range employing polyclonal antibodies. It has also been implemented employing the WHO-approved anti-SARS-CoV-2 immunoglobulin standard. A clinical validation with COVID-19 positive and negative samples (n = 120) demonstrates its excellent diagnostic sensitivity (99%) and specificity (100%). This positions our biosensor as an accurate and easy-to-use diagnostics tool for rapid and reliable COVID-19 serology to be employed both at laboratory and decentralized settings for the disease management and for the evaluation of immunological status during vaccination or treatment.


Subject(s)
Biosensing Techniques , COVID-19 , Antibodies, Viral , Humans , Pandemics , SARS-CoV-2 , Sensitivity and Specificity
8.
Biosens Bioelectron ; 200: 113924, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1599524

ABSTRACT

In a published review entitled "COVID-19 diagnosis -A review of current methods", the authors considered hemagglutinin esterase as one of the structural proteins of SARS-CoV-2 and also they did not represent ORF3b, ORF9b, and ORF9c in SARS-CoV-2 genome structure. However, according to the scientific evidence, among coronaviruses only some betacoronaviruses (Embecovirus subgenera) contain HE, and the genome of most of the coronaviruses such as SARS-CoV-2, SARS-CoV, and MERS-CoV lack the HE gene. In addition, the genome of SARS-CoV-2 contains several accessory proteins ORFs including ORF3a, ORF3b, ORF6, ORF7a, ORF7b, ORF8, ORF9b, ORF9c, and ORF10.


Subject(s)
Biosensing Techniques , COVID-19 , COVID-19 Testing , Humans , Open Reading Frames , SARS-CoV-2
9.
ACS Appl Bio Mater ; 4(12): 8110-8128, 2021 12 20.
Article in English | MEDLINE | ID: covidwho-1597218

ABSTRACT

The design of advanced nanobiomaterials to improve analytical accuracy and therapeutic efficacy has become an important prerequisite for the development of innovative nanomedicines. Recently, phospholipid nanobiomaterials including 2-methacryloyloxyethyl phosphorylcholine (MPC) have attracted great attention with remarkable characteristics such as resistance to nonspecific protein adsorption and cell adhesion for various biomedical applications. Despite many recent reports, there is a lack of comprehensive review on the phospholipid nanobiomaterials from synthesis to diagnostic and therapeutic applications. Here, we review the synthesis and characterization of phospholipid nanobiomaterials focusing on MPC polymers and highlight their attractive potentials for applications in micro/nanofabricated fluidic devices, biosensors, lab-on-a-chip, drug delivery systems (DDSs), COVID-19 potential usages for early diagnosis and even treatment, and artificial extracellular matrix scaffolds for cellular engineering.


Subject(s)
Biocompatible Materials/chemistry , Drug Carriers/chemistry , Lab-On-A-Chip Devices , Nanostructures/chemistry , Phospholipids/chemistry , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , COVID-19/diagnosis , COVID-19/drug therapy , COVID-19/virology , Humans , Microscopy, Confocal , SARS-CoV-2/isolation & purification
10.
Nano Lett ; 22(1): 50-57, 2022 01 12.
Article in English | MEDLINE | ID: covidwho-1596792

ABSTRACT

SARS-CoV-2 variants are of particular interest because they can potentially increase the transmissibility and virulence of COVID-19 or reduce the effectiveness of available vaccines. However, screening SARS-CoV-2 variants is a challenge because biosensors target viral components that can mutate. One promising strategy is to screen variants via angiotensin-converting enzyme 2 (ACE2), a virus receptor shared by all known SARS-CoV-2 variants. Here we designed a highly sensitive and portable COVID-19 screening biosensor based on the virus receptor. We chose a dual-gate field-effect transistor to overcome the low sensitivity of virus-receptor-based biosensors. To optimize the biosensor, we introduced a synthetic virus that mimics the important features of SARS-CoV-2 (size, bilayer structure, and composition). The developed biosensor successfully detected SARS-CoV-2 in 20 min and showed sensitivity comparable to that of molecular diagnostic tests (∼165 copies/mL). Our results indicate that a virus-receptor-based biosensor can be an effective strategy for screening infectious diseases to prevent pandemics.


Subject(s)
Biosensing Techniques , COVID-19 , SARS-CoV-2/isolation & purification , Humans , Receptors, Virus , Spike Glycoprotein, Coronavirus
11.
Anal Chem ; 94(2): 714-722, 2022 01 18.
Article in English | MEDLINE | ID: covidwho-1596741

ABSTRACT

Considering the large-scale outbreak of the coronavirus, it is essential to develop a versatile sensing system for different coronaviruses diagnostics, such as COVID-19, severe acute respiratory syndrome-related coronavirus (SARS-CoV), and bat SARS-like coronavirus (Bat-SL-CoVZC45). In this work, a tetrahedron-based constitutional dynamic network was built as the sensing platform for coronavirus detection. Four different DNA probes were used to construct the tetrahedron structure. DNAzyme and the fluorophore modified substrate strand were used to generate different fluorescence signals, which can be used to distinguish different coronaviruses. The coronavirus biosensor shows a high sensitivity for COVID-19, Bat-SL-CoVZC45, and SARS-CoV detection, with detection limits of 2.5, 3.1, and 2.9 fM, respectively. Also, the platform is robust, and the possible interference from clinical samples was negligible. Using different coronaviruses as inputs, we have fabricated several concatenated logic gates, such as "AND-OR", "INHIBIT-AND", "AND-AND-AND", and "AND-INHIBIT". Importantly, our logic system can also be used to identify SARS-CoV-2 Delta and Lambda variants in the logic operations. Due to the unique advantages of high sensitivity and selectivity, multiple logic biocomputing capabilities, and multireadout mode, this flexible sensing system provides a versatile sensing strategy for intelligent diagnostics of different coronaviruses with low false-negative rates.


Subject(s)
Biosensing Techniques , COVID-19 , DNA, Catalytic , Humans , SARS-CoV-2
12.
Biosens Bioelectron ; 200: 113900, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1588212

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the major shortcoming of healthcare systems globally in their inability to diagnose the disease rapidly and accurately. At present, the molecular approaches for diagnosing COVID-19 primarily use reverse transcriptase polymerase chain reaction (RT-PCR) to create and amplify cDNA from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. Although molecular tests are reported to be specific, false negatives are quite common. Furthermore, literally all these tests require a step involving RNA isolation which does not make them point-of-care (POC) in the true sense. Here, we report a lateral flow strip-based RNA extraction and amplification-free nucleic acid test (NAT) for rapid diagnosis of positive COVID-19 cases at POC. The assay uses highly specific 6-carboxyfluorescein (6-FAM) and biotin labeled antisense oligonucleotides (ASOs) as probes those are designed to target N-gene sequence of SARS-CoV-2. Additionally, we utilized cysteamine capped gold-nanoparticles (Cyst-AuNPs) to augment the signal further for enhanced sensitivity. Without any large-stationary equipment and highly trained staffers, the entire sample-to-answer approach in our case would take less than 30 min from a patient swab sample collection to final diagnostic result. Moreover, when evaluated with 60 clinical samples and verified with an FDA-approved TaqPath RT-PCR kit for COVID-19 diagnosis, the assay obtained almost 99.99% accuracy and specificity. We anticipate that the newly established low-cost amplification-free detection of SARS-CoV-2 RNA will aid in the development of a platform technology for rapid and POC diagnosis of COVID-19 and other pathogens.


Subject(s)
Biosensing Techniques , COVID-19 , Metal Nanoparticles , COVID-19 Testing , Gold , Humans , Nucleic Acid Amplification Techniques , Point-of-Care Systems , RNA, Viral/genetics , SARS-CoV-2 , Sensitivity and Specificity
13.
Biosens Bioelectron ; 200: 113909, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1588211

ABSTRACT

Coronavirus disease 2019 (COVID-19) has been recognized as a global pandemic outbreak, opening the most severe socio-economic crisis since World War II. Different scientific activities have been emerged in this global scenario, including the development of innovative analytical tools to measure nucleic acid, antibodies, and antigens in the nasopharyngeal swab, serum, and saliva for prompt identification of COVID-19 patients and to evaluate the immune response to the vaccine. The detection of SARS-CoV-2 in saliva remains a challenge for the lack of sufficient sensitivity. To address this issue, we developed a novel paper-based immunoassay using magnetic beads to support the immunological chain and 96-well wax-printed paper plate as a platform for color visualization by using a smartphone combined with Spotxel free-charge app. To assess the reliability of the measurement of SARS-CoV-2 in saliva, untreated saliva was used as a specimen and the calibration curve demonstrated a dynamic range up to 10 µg/mL, with a detection limit equal to 0.1 µg/mL. The effectiveness of this sustainable analytical tool in saliva was evaluated by comparing the data with the nasopharyngeal swab specimens sampled by the same patients and tested with Real-Time PCR reference method, founding 100% of agreement, even in the case of high Cycle Threshold (CT) numbers (low viral load). Furthermore, the positive saliva samples were characterized by the next-generation sequencing method, demonstrating the capability to detect the Delta variant, which is actually (July 2021) the most relevant variant of concern.


Subject(s)
Biosensing Techniques , COVID-19 , Colorimetry , Humans , Immunoassay , Magnetic Phenomena , Nasopharynx , Reproducibility of Results , SARS-CoV-2 , Saliva , Smartphone , Specimen Handling
14.
Biosens Bioelectron ; 200: 113912, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1588210

ABSTRACT

SARS, a new type of respiratory disease caused by SARS-CoV, was identified in 2003 with significant levels of morbidity and mortality. The recent pandemic of COVID-19, caused by SARS-CoV-2, has generated even greater extents of morbidity and mortality across the entire world. Both SARS-CoV and SARS-CoV-2 spreads through the air in the form of droplets and potentially smaller droplets (aerosols) via exhaling, coughing, and sneezing. Direct detection from such airborne droplets would be ideal for protecting general public from potential exposure before they infect individuals. However, the number of viruses in such droplets and aerosols is too low to be detected directly. A separate air sampler and enough collection time (several hours) are necessary to capture a sufficient number of viruses. In this work, we have demonstrated the direct capture of the airborne droplets on the paper microfluidic chip without the need for any other equipment. 10% human saliva samples were spiked with the known concentration of SARS-CoV-2 and sprayed to generate liquid droplets and aerosols into the air. Antibody-conjugated submicron particle suspension is then added to the paper channel, and a smartphone-based fluorescence microscope isolated and counted the immunoagglutinated particles on the paper chip. The total capture-to-assay time was <30 min, compared to several hours with the other methods. In this manner, SARS-CoV-2 could be detected directly from the air in a handheld and low-cost manner, contributing to slowing the spread of SARS-CoV-2. We can presumably adapt this technology to a wide range of other respiratory viruses.


Subject(s)
Biosensing Techniques , COVID-19 , SARS Virus , Aerosols , Humans , Microfluidics , SARS-CoV-2 , Smartphone
15.
Biosens Bioelectron ; 200: 113922, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1588209

ABSTRACT

Fast, affordable, portable, and sensitive technology to detect COVID-19 is critical to address the current outbreak. Here, we present a CRISPR/Cas12a-derived electrochemical aptasensor for cost-effective, fast, and ultrasensitive COVID-19 nucleocapsid protein (Np) detection. First, an electrochemical sensing interface was fabricated by immobilizing methylene blue labeled poly adenines DNA sequence (polyA-MB electrochemical reporter) on a gold electrode surface. Second, an arched probe was prepared via hybridization of Np aptamer and an activator strand. In the presence of COVID-19 Np, the activator strand could be released from the arched probe due to the specific interaction between the target and the aptamer, which then activated the trans-cleavage activity of the CRISPR/Cas12a system. Subsequently, the polyA-MB reporters were cleaved from the electrode surface, decreasing the current of differential pulse voltammetry (DPV) at a potential of -0.27 V(vs. Ag/AgCl). The CRISPR/Cas12a-derived electrochemical aptasensor shows a highly efficient performance for COVID-19 Np detection in 50 pg mL-1 to 100 ng mL-1 with a limit of detection (LOD) low to 16.5 pg mL-1. Notably, the whole process of one test can be completed within 30 min. Simultaneously, the aptasensor displays a high selectivity to other proteins. The further measurements demonstrate that the aptasensor is robust in a natural system for point-of-care testing, such as in tap water, milk, or serum. The aptasensor is universal and expandable and holds great potential in the COVID-19 early diagnosis, environmental surveillance, food security, and other aspects.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , COVID-19 , CRISPR-Cas Systems , Electrochemical Techniques , Electrodes , Gold , Humans , Limit of Detection , Nucleocapsid Proteins , SARS-CoV-2
16.
Biosens Bioelectron ; 200: 113925, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1588208

ABSTRACT

The current COVID-19 pandemic caused by SARS-CoV-2 is raging, seriously threatening people's lives. The establishment of rapid and accurate pathogen detection technology is not only critical in this epidemic, but also a reminder that we must always be prepared for possible future outbreaks. Therefore, we developed a Palm Germ-Radar (PaGeR) device for rapid and simple detection of COVID-19 from extracted patient sample RNA by RT-LAMP. The whole procedure of rapid COVID-19 detection is based on 4 simple steps: inactivation, extraction, amplification, and detection. SARS-CoV-2 down to 1 copy/µL could be detected selectively with naked-eye. Three detection methods (colorimetric, fluorometric and lateral dipstick readout) could be performed in PaGeR instrument. By employing the PaGeR, we successfully detected SARS-CoV-2 in clinical RNA samples isolated from swab specimens. The results showed that 15 out of 17 COVID-19 patients were diagnosed as positive while all 55 normal samples were diagnosed as negative. Therefore, the developed PaGeR instrument can realize the detection of COVID-19 with easily visualized results, providing a promising instrument for rapid detection in the community as well as at home.


Subject(s)
Biosensing Techniques , COVID-19 , Humans , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Pandemics , RNA, Viral/genetics , Radar , Reverse Transcription , SARS-CoV-2 , Sensitivity and Specificity
17.
Biosensors (Basel) ; 11(12)2021 Dec 17.
Article in English | MEDLINE | ID: covidwho-1581025

ABSTRACT

In light of the recent Coronavirus disease (COVID-19) pandemic, peripheral oxygen saturation (SpO2) has shown to be amongst the vital signs most indicative of deterioration in persons with COVID-19. To allow for the continuous monitoring of SpO2, we attempted to demonstrate accurate SpO2 estimation using our custom chest-based wearable patch biosensor, capable of measuring electrocardiogram (ECG) and photoplethysmogram (PPG) signals with high fidelity. Through a breath-hold protocol, we collected physiological data with a wide dynamic range of SpO2 from 20 subjects. The ratio of ratios (R) used in pulse oximetry to estimate SpO2 was robustly extracted from the red and infrared PPG signals during the breath-hold segments using novel feature extraction and PPGgreen-based outlier rejection algorithms. Through subject independent training, we achieved a low root-mean-square error (RMSE) of 2.64 ± 1.14% and a Pearson correlation coefficient (PCC) of 0.89. With subject-specific calibration, we further reduced the RMSE to 2.27 ± 0.76% and increased the PCC to 0.91. In addition, we showed that calibration is more efficiently accomplished by standardizing and focusing on the duration of breath-hold rather than the resulting range in SpO2. The accurate SpO2 estimation provided by our custom biosensor and the algorithms provide research opportunities for a wide range of disease and wellness monitoring applications.


Subject(s)
COVID-19 , Monitoring, Physiologic/instrumentation , Wearable Electronic Devices , Biosensing Techniques , COVID-19/diagnosis , Electrocardiography , Humans , Oximetry , Oxygen , Photoplethysmography , Sternum
18.
Sensors (Basel) ; 22(1)2021 Dec 25.
Article in English | MEDLINE | ID: covidwho-1580506

ABSTRACT

Plasmonic metasurfaces have been widely used in biosensing to improve the interaction between light and biomolecules through the effects of near-field confinement. When paired with biofunctionalization, plasmonic metasurface sensing is considered as a viable strategy for improving biomarker detection technologies. In this review, we enumerate the fundamental mechanism of plasmonic metasurfaces sensing and present their detection in human tumors and COVID-19. The advantages of rapid sampling, streamlined processes, high sensitivity, and easy accessibility are highlighted compared with traditional detection techniques. This review is looking forward to assisting scientists in advancing research and developing a new generation of multifunctional biosensors.


Subject(s)
Biosensing Techniques , COVID-19 , Neoplasms , Humans , SARS-CoV-2
19.
Sensors (Basel) ; 21(24)2021 Dec 15.
Article in English | MEDLINE | ID: covidwho-1572596

ABSTRACT

Life was once normal before the first announcement of COVID-19's first case in Wuhan, China, and what was slowly spreading became an overnight worldwide pandemic. Ever since the virus spread at the end of 2019, it has been morphing and rapidly adapting to human nature changes which cause difficult conundrums in the efforts of fighting it. Thus, researchers were steered to investigate the virus in order to contain the outbreak considering its novelty and there being no known cure. In contribution to that, this paper extensively reviewed, compared, and analyzed two main points; SARS-CoV-2 virus transmission in humans and detection methods of COVID-19 in the human body. SARS-CoV-2 human exchange transmission methods reviewed four modes of transmission which are Respiratory Transmission, Fecal-Oral Transmission, Ocular transmission, and Vertical Transmission. The latter point particularly sheds light on the latest discoveries and advancements in the aim of COVID-19 diagnosis and detection of SARS-CoV-2 virus associated with this disease in the human body. The methods in this review paper were classified into two categories which are RNA-based detection including RT-PCR, LAMP, CRISPR, and NGS and secondly, biosensors detection including, electrochemical biosensors, electronic biosensors, piezoelectric biosensors, and optical biosensors.


Subject(s)
Biosensing Techniques , COVID-19 , COVID-19 Testing , Human Body , Humans , SARS-CoV-2
20.
ACS Appl Mater Interfaces ; 13(50): 60612-60624, 2021 Dec 22.
Article in English | MEDLINE | ID: covidwho-1569206

ABSTRACT

New analytical techniques that overcome major drawbacks of current routinely used viral infection diagnosis methods, i.e., the long analysis time and laboriousness of real-time reverse-transcription polymerase chain reaction (qRT-PCR) and the insufficient sensitivity of "antigen tests", are urgently needed in the context of SARS-CoV-2 and other highly contagious viruses. Here, we report on an antifouling terpolymer-brush biointerface that enables the rapid and sensitive detection of SARS-CoV-2 in untreated clinical samples. The developed biointerface carries a tailored composition of zwitterionic and non-ionic moieties and allows for the significant improvement of antifouling capabilities when postmodified with biorecognition elements and exposed to complex media. When deployed on a surface of piezoelectric sensor and postmodified with human-cell-expressed antibodies specific to the nucleocapsid (N) protein of SARS-CoV-2, it made possible the quantitative analysis of untreated samples by a direct detection assay format without the need of additional amplification steps. Natively occurring N-protein-vRNA complexes, usually disrupted during the sample pre-treatment steps, were detected in the untreated clinical samples. This biosensor design improved the bioassay sensitivity to a clinically relevant limit of detection of 1.3 × 104 PFU/mL within a detection time of only 20 min. The high specificity toward N-protein-vRNA complexes was validated both by mass spectrometry and qRT-PCR. The performance characteristics were confirmed by qRT-PCR through a comparative study using a set of clinical nasopharyngeal swab samples. We further demonstrate the extraordinary fouling resistance of this biointerface through exposure to other commonly used crude biological samples (including blood plasma, oropharyngeal, stool, and nasopharyngeal swabs), measured via both the surface plasmon resonance and piezoelectric measurements, which highlights the potential to serve as a generic platform for a wide range of biosensing applications.


Subject(s)
COVID-19 Testing , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/chemistry , Nasal Mucosa/virology , Polymers/chemistry , RNA, Viral/metabolism , SARS-CoV-2 , Biofouling , Biological Assay , Biosensing Techniques , Humans , Ions , Limit of Detection , Mass Spectrometry , Nasopharynx/virology , Phosphoproteins/chemistry , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Specimen Handling
SELECTION OF CITATIONS
SEARCH DETAIL
...