Electrochemical Biosensor Based on Laser-Induced Graphene for COVID-19 Diagnosing: Rapid and Low-Cost Detection of SARS-CoV-2 Biomarker Antibodies

The severe acute respiratory syndrome originated by the new coronavirus (SARS-CoV-2) that emerged in late 2019, known to be a highly transmissible and pathogenic disease, has caused the COVID-19 global pandemic outbreak. Thus, diagnostic devices that help epidemiological public safety measures to reduce undetected cases and isolation of infected patients, in addition to significantly help to control the population's immune response to vaccine, are required. To address the negative issues of clinical research, we developed a Diagnostic on a Chip platform based on a disposable electrochemical biosensor containing laser-induced graphene and a protein (SARS-CoV-2 specific antigen) for the detection of SARS-CoV-2 antibodies. The biosensors were produced via direct laser writing using a CO2 infrared laser cutting machine on commercial polyimide sheets. The presence of specific antibodies reacting with the protein and the K3[Fe(CN)6] redox indicator produced characteristic and concentration-dependent electrochemical signals, with mean current values of 9.6757 and 8.1812 µA for reactive and non-reactive samples, respectively, proving the effectiveness of testing in clinical samples of serum from patients. Thus, the platform is being expanded to be measured in a portable microcontrolled potentiostat to be applied as a fast and reliable monitoring and mapping tool, aiming to assess the vaccinal immune response of the population.

PEDOT-AuNPs-based impedimetric immunosensor for the detection of SARS-CoV-2 antibodies.

Electrochemical sensors and biosensors are useful techniques for fast, inexpensive, sensitive, and easy detection of innumerous specimen. In face of COVID-19 pandemic, it became evident the necessity of a rapid and accurate diagnostic test, so the impedimetric immunosensor approach can be a good alternative to replace the conventional tests due to the specific antibody-antigen binding interaction and the fast response in comparison to traditional methods. In this work, a modified electrode with electrosynthesized PEDOT and gold nanoparticles followed by the immobilization of truncated nucleoprotein (N aa160-406aa) was used for a fast and reliable detection of antibodies against COVID-19 in human serum sample. The method consists in analyzing the charge-transfer resistance (RCT) variation before and after the modified electrode comes into contact with the positive and negative serum sample for COVID-19, using [Fe(CN)6]3-/4- as a probe. The results show a linear and selective response for serum samples diluted in a range of 2.5 × 103 to 20 × 103. Also, the electrode material was fully characterized by Raman spectroscopy, transmission electron microscopy and scanning electron microscopy coupled with EDS, indicating that the gold nanoparticles were well distributed around the polymer matrix and the presence of the biological sample was confirmed by EDS analysis. EIS measurements allowed to differentiate the negative and positive samples by the difference in the RCT magnitude, proving that the material developed here has potential properties to be applied in impedimetric immunosensors for the detection of SARS-CoV-2 antibodies in about 30 min.

The Use of Lectins as Tools to Combat SARS-CoV-2.

BACKGROUND: In December 2019, China announced the first case of an infection caused by an, until then, unknown virus: SARS-CoV-2. Since then, researchers have been looking for viable alternatives for the treatment and/or cure of viral infection. Among the possible complementary solutions are lectins, proteins that are reversibly bound to different carbohydrates. The Spike protein, present on the viral surface, can interact with different cell receptors: ACE2, CD147, and DC-SIGNR. Since lectins have an affinity for different carbohydrates, the binding with the glycosylated cell receptors represents a possibility of preventing the virus from binding to the receptors of host cells. OBJECTIVE: In this review, we discuss the main lectins that are possible candidates for use in the treatment of Covid-19, highlighting those that have already demonstrated antiviral activity in vivo and in vitro, including mannose-binding lectin, Griffithsin, BanLec, and others. We also aim to discuss the possible mechanism of action of lectins, which appears to occur through the mediation of viral fusion in host cells, by binding of lectins to glycosylated receptors found in human cells and/or binding of these proteins with the spike glycoprotein, present in virus surface. Moreover, we discuss the use of lectins in clinical practice. CONCLUSION: Even with the development of effective vaccines, new cases of viral infection with the same virus, or new outbreaks with different viruses can occur; so, the development of new treatments should not be discarded. Moreover, the discussions made in this work are relevant regarding the anti-viral properties of lectins.

Impact of novel coronavirus Disease-19 (COVID-19) pandemic in Italian pediatric emergency departments: a national survey.

BACKGROUND: Coronavirus Disease-19 (COVID-19) has rapidly become a pandemic emergency, distressing health systems in each affected country. Preparation strategies for managing this pandemic have been keys to face the COVID-19 surge all over the world and all levels of care. MATERIALS AND METHODS: During the epidemic, the Italian society of pediatric emergency-urgency (SIMEUP) promoted a national survey aiming to evaluate preparedness and response of pediatric emergency departments (PED) critical in ensuring optimal management of COVID-19 cases. RESULTS: Our results suggest that Italian PED have promptly set a proactive approach to the present emergency. 98.9% of the hospitals have defined special pathways and assistive protocols concerning the management of pediatric COVID-19 cases. The highest percentage of application of the measures for preventive and protective for COVID-19 concerned the use of personal protective equipments. CONCLUSIONS: Results show that the following measures for pediatric patients, admitted in PED, have been promptly implemented throughout the whole country: eg. use of protective devices, pre-triage of patients accessing the hospital. Despite COVID-19 being a new threat, we have shown that by developing an easy-to-follow decision algorithm and clear plans for the interventional platform teams, we can ensure optimal health care workers and patients' safety.