Fabrication and characterization of field effect transistor based on single walled carbon nanotubes

Objectives Sensor Biology and sensor devices have been advancing since its inceptions. In this work, we report fabrication of carbon nanotubes filed-effect transistor (CNT-FET) sensor and its characterization. CNT intensively has been used in the construction of sensing layers due to their exceptional features, large surface area, stability, high mechanical strength, adaptability, and functional behavior. Methods Carbon nanotubes (CNTs) as semiconductor were fabricated as an active nanomaterial between the source-drain electrodes. The fabrication of CNT-FETs performed by following conventional photolithography method and lift-off techniques. Results The structural morphology of deposited CNT was confirmed by the scanning electron micrograph (SEM) imaging. The transfer curves between drain-source were considered as a function of the drain-source voltage (VDS) and gate-source voltage (VGS) from individual CNT-FET fabricated wafer. The characterized Ion/Ioff ratio was calculated for every CNT-FET device. The semiconductor properties of the fabricated CNT-FET device characterized by the source-drain current (IDS) versus gate voltage (VGS). Conclusions CNT-FET based device have advantages of low cost fabrication, quick response, increased sensitivity, small size, and high flexibility. CNT-FETs have been used comprehensively in the biosensing of chemicals, proteins, nucleic acids, bacteria, and virus etc. This device could be used for SARS-CoV-2 and related variant detection in current scenario.

Role of herbal medicines in the management of patients with COVID-19: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIM: The management of the worldwide spreading COVID-19 consists of amelioration of its symptoms but no cure is yet available. Herbal medicines supplemented with the Western medicine have been applied for COVID-19 treatment in India, China, Iran, and other countries. This systematic review and meta-analysis of RCTs evaluates the effect and safety of herbal intervention in the management of COVID-19. EXPERIMENTAL PROCEDURE: RCTs from databases like PubMed, Cochrane Library, ScienceDirect, Google Scholar, Science Direct, CTRI, AYUSH Research Portal, India, were reviewed and the data were extracted for study sample demographics, intervention details, clinical effect, inflammatory markers and safety monitoring. Outcomes were expressed as Risk-ratio (RR) with 95% CI for dichotomous data, and Mean-Difference (MD) with 95% CI for continuous data. RESULT AND CONCLUSION: From the 32 eligible studies, a total of 3177 COVID-19 patients were included in the review. Herbal intervention as an adjuvant to Western medicine causes significantly higher improvement compared to Western medicine alone [Fever (RR = 1.09 CI 1.03, 1.15), Cough (Risk-Ratio = 1.22 CI 1.08, 1.37), Fatigue (Risk-Ratio = 1.27 CI 1.11, 1.44), Chest CT Improvement (Risk-Ratio = 1.15 CI 1.08, 1.23)]. The laboratory parameters were also better in the herbal medicine group compared to standard care group only WBC (MD = 0.36 CI 0.16, 0.55), Lymphocyte percentage (MD = 5.48 CI 3.05, 7.92), Absolute lymphocyte count (MD = 0.23 CI 0.07, 0.39), CRP (MD = -5.66 CI -7.96, -3.37). However, duration of hospital stays (MD = -1.82 CI -3.84, 0.21); IL-6 (MD = -3.67 CI -8.76, 1.43), ESR Level (MD = -10.38 CI -25.96, 5.21) were statistically insignificant. No significant adverse events for herbal medications were noted in the included RCTs, during the time of the studies. (n = 665, RR 0.93; 95% CI 0.76, 1.14).

An immunosensor based on a high performance dual-gate oxide semiconductor thin-film transistor for rapid detection of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of an infectious disease that has led the WHO to declare its highest level (6) pandemic. The coronavirus disease 2019 (COVID-19) has spread rapidly around the world, and the number of confirmed cases has passed 246 million as of November 2021. Therefore, precise and fast virus detection protocols need to be developed to cope with the rapid spread of the virus. Here, we present a high performance dual-gate oxide semiconductor thin-film transistor (TFT)-based immunosensor for detecting SARS-CoV-2. The immunosensor has an indium tin oxide sensing membrane to which the antibody against the SARS-CoV-2 spike S1 protein can be immobilized through functionalization. The dual-gate TFT was stable under ambient conditions with near-zero hysteresis; capacitive coupling yields a 10.14 ± 0.14-fold amplification of the surface charge potential on the sensing membrane and improves the pH sensitivity to 770.1 ± 37.74 mV pH-1 above the Nernst limit. The immunosensor could rapidly detect the SARS-CoV-2 spike S1 protein and cultured SARS-CoV-2 in 0.01× PBS with high antigen selectivity and sensitivity. Our immunosensor can accurately measure the electrical changes originated from SARS-CoV-2, without the need for polymerase chain reaction tests or labeling.

Carbon nanotube field-effect transistor (CNT-FET)-based biosensor for rapid detection of SARS-CoV-2 (COVID-19) surface spike protein S1.

The large-scale diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important for traceability and treatment during pandemic outbreaks. We developed a fast (2-3 min), easy-to-use, low-cost, and quantitative electrochemical biosensor based on carbon nanotube field-effect transistor (CNT-FET) that allows digital detection of the SARS-CoV-2 S1 in fortifited saliva samples for quick and accurate detection of SARS-CoV-2 S1 antigens. The biosensor was developed on a Si/SiO2 surface by CNT printing with the immobilization of a anti-SARS-CoV-2 S1. SARS-CoV-2 S1 antibody was immobilized on the CNT surface between the S-D channel area using a linker 1-pyrenebutanoic acid succinimidyl ester (PBASE) through non-covalent interaction. A commercial SARS-CoV-2 S1 antigen was used to characterize the electrical output of the CNT-FET biosensor. The SARS-CoV-2 S1 antigen in the 10 mM AA buffer pH 6.0 was effectively detected by the CNT-FET biosensor at concentrations from 0.1 fg/mL to 5.0 pg/mL. The limit of detection (LOD) of the developed CNT-FET biosensor was 4.12 fg/mL. The selectivity test was performed by using target SARS-CoV-2 S1 and non-target SARS-CoV-1 S1 and MERS-CoV S1 antigens in the 10 mM AA buffer pH 6.0. The biosensor showed high selectivity (no response to SARS-CoV-1 S1 or MERS-CoV S1 antigen) with SARS-CoV-2 S1 antigen detection in the 10 mM AA buffer pH 6.0. The biosensor is highly sensitive, saves time, and could be a helpful platform for rapid detection of SARS-CoV-2 S1 antigen from the patients saliva.

Penta-peptide ATN-161 based neutralization mechanism of SARS-CoV-2 spike protein.

SARS-CoV-2 has become a big challenge for the scientific community worldwide. SARS-CoV-2 enters into the host cell by the spike protein binding with an ACE2 receptor present on the host cell. Developing safe and effective inhibitor appears an urgent need to interrupt the binding of SARS-CoV-2 spike protein with ACE2 receptor in order to reduce the SARS-CoV-2 infection. We have examined the penta-peptide ATN-161 as potential inhibitor of ACE2 and SARS-CoV-2 spike protein binding, where ATN-161 has been commercially approved for the safety and possess high affinity and specificity towards the receptor binding domain (RBD) of S1 subunit in SARS-CoV-2 spike protein. We carried out experiments and confirmed these phenomena that the virus bindings were indeed minimized. ATN-161 peptide can be used as an inhibitor of protein-protein interaction (PPI) stands as a crucial interaction in biological systems. The molecular docking finding suggests that the binding energy of the ACE2-spike protein complex is reduced in the presence of ATN-161. Protein-protein docking binding energy (-40.50 kcal/mol) of the spike glycoprotein toward the human ACE2 and binding of ATN-161 at their binding interface reduced the biding energy (-26.25 kcal/mol). The finding of this study suggests that ATN-161 peptide can mask the RBD of the spike protein and be considered as a neutralizing candidate by binding with the ACE2 receptor. Peptide-based masking of spike S1 protein (RBD) and its neutralization is a highly promising strategy to prevent virus penetration into the host cell. Thus masking of the RBD leads to the loss of receptor recognition property which can reduce the chance of infection host cells.

Review: Roles of human serum albumin in prediction, diagnoses and treatment of COVID-19.

The severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) keeps on destroying normal social integrity worldwide, bringing about extraordinary medical services, cultural and financial interruption. Individuals with diabetes have been demonstrated to be at higher risk of complications and even death when exposed to SARS-CoV-2. Regardless of pandemic scale infection, there is presently limited comprehension on the potential impact of SARS-CoV-2 on individuals with diabetes. Human serum albumin (HSA) is the most abundant circulating plasma protein in human serum and attracted more interest from researchers because most susceptible to non-enzymatic glycation reactions. Albumin down-regulates the expression of ACE2 that is the target receptor of COVID-19. Hypoalbuminemia, coagulopathy, and vascular disease have been connected in COVID-19 and appear to predict outcomes independent of age and morbidity. This review discusses the most recent evidence that the ACE/ACE2 ratio could influence by human serum albumin both the susceptibility of individuals to SARS-CoV-2 infection and the outcome of the COVID-19 disease.