ABSTRACT
A SARS-CoV-2 biosensor based on the biorecognition of the spike protein to the angiotensin-converting enzyme 2 (ACE-2) transmembrane receptor was developed using entire cell membranes as the biorecognition layer. In this new SARS-CoV-2 detection platform, cellular membranes from VeroCCL81 (mVero) and Calu-3 (mCalu) cells (which overexpress the ACE-2 transmembrane receptors) were extracted and immobilized as vesicles on an indium tin oxide electrode (ITO). Electrochemical impedance spectroscopy was used to optimize the performance of the developed devices for SARS-CoV-2 detection. This novel biosensor comprises a low-cost system (less than one US$ dollar) that uses the unique properties of cell membranes combined with the catalytic properties of electrochemical platforms to allow spike proteins recognition. A linear response from 10 to 100 ng/mL was obtained from the optimized biosensors, a limit of detection of 10.0 pg/mL and 7.25 pg/mL and limit of quantification of 30.4 pg/mL and 21.9 pg/mL were achieved with satisfactory accuracy for ITO-APTES-mVero and ITO-APTES-mCalu, respectively. Selectivity studies revealed that this platform was able to differentiate the target spike proteins from NS1 proteins from dengue and Zika viruses. In addition, sensors comprising cell membranes devoid of the ACE-2 transmembrane receptor exhibited no biorecognition signal. The developed devices are suitable for SARS-CoV-2 detection based on spike protein recognition, and capable of providing a low-cost, accurate, and accessible tool for use in a pandemic and post-pandemic scenario. [Display omitted] • Investigation on the interactions between natural cell membranes and Spike virus. • Influence of the ACE-2 receptors at the electrode surface to detect SARS-CoV-2. • Differentiation between SARS-CoV-2 from Dengue and Zika Virus using membrane cells elements. [ FROM AUTHOR]
ABSTRACT
Drug- Induced Acute Interstitial Nephritis is a known cause of AKI commonly caused by NSAIDS, PPI and antibiotics which have been well documented in the literature. The hallmark presentation is fever, rash and eosinophilia, although this is only seen in a minority of cases. Half of cases do not present with AKI and therefore the clinician must have a high index of suspicion for further workup. Early detection can lead to early treatment which should result in improved outcomes. 67 Gallium renal scan Scintigraphy has been used over the last 30 years to help diagnose AIN, however no known use of Indium-111 WBC Scan has been used to in the diagnosis of AIN. A 71-year-old male presented with fevers and generalized weakness for 4 days, endorsing associated paresthesias in both lower extremities as well as visual hallucinations. After a primary care physician outpatient visit, a WBC Scan showed localization to bilateral kidneys and the colon. He was sent to the hospital for IV antibiotics as bilateral pyelonephritis was suspected. Initial labs was significant for WBC of 11.4k (without Eosinophilia), serum creatinine of 1.73 (Baseline 1.1). Urinalysis was negative for infection however with trace proteinuria. Covid test was negative. Three sets of blood cultures were negative. Imaging was negative for acute pathology. IV antibiotics were started without resolution of symptoms. Transthoracic Echo was negative for any vegetations. Patient continued to have fevers. He stated that he was started on hydralazine three weeks prior to admission. After cessation of Hydralazine he ceased to have fevers. Case was discussed with Radiology and he had a renal biopsy. Biopsy results confirmed mild AIN, 45% global sclerosis, severe arterial and arteriolar sclerosis, tubular atrophy and interstitial fibrosis. He was started on Prednisone and tapered over 2 months. Renal function returned to baseline. AIN was suspected because of recent initiation of Hydralazine even though neither rash nor eosinophilia was present. A positive Indium-111 WBC Scan in the setting of fever, AKI and elevated WBC count encouraged us to proceed with the biopsy even though the patients' AKI had “resolved.” Here we aim to show that Indium-111 WBC assisted in the diagnosis of AIN and could be used in the future for clinicians as an indication for biopsy.
ABSTRACT
A multi-faceted energy intensive technology that can be used for water disinfection and synthesis of electrolysed water (EW) is the need of the hour to achieve a sustainable post COVID 19 water management strategy. Direct sunlight driven processes are legislatively green technologies and hold the key in environmental sustenance. The development of a laboratory proto type reactor powered by a photovoltaic module for the treatment open source river water is described in this paper. This paper reports on the efficacy of the developed proto type technology for multipurpose application namely: (1) the production of Electrolysed water (EW) in a cost efficient manner using direct sunlight and (2) the removal of organic impurity from water using direct sunlight without the use of any photo catalyst or membrane. The prototype reactor utilizes chemical spray pyrolysis deposited highly photo-conducting indium sulphide thin films grown on fluorine doped tin oxide (F:SnO2) substrate (coated using chemical spray pyrolysis technique in-house) as the photo electrode. Dissolved organic matter arising in river water has distinctive fluorescence properties, and this research has utilized it to identify dissolved organic substances in both random samples and treated water. The work proves that photovoltaic module powered electrolytic reactors consisting of In2S3 electrodes can be used for treatment of river water. A diaphragm free, energy intensive route for the production of electrolysed water with the use of non-hazardous NaCl as the electrolyte has been demonstrated here. We conclude that In2S3 electrodes can be used for non-photo catalytic reduction of humic-derived impurities in river water. These results are also encouraging on the prospects of treating Nitrates present in the river water. The likes of techniques as described in this report that do not use photo catalyst or membranes may pave way for real time photovoltaic module powered floating reactors that can decontaminate water bodies on a large scale. The technique used by us demonstrates that a chlorine free route can be optimized for the synthesis of EW eliminating the production of large amounts of wastewater with high levels of biological oxygen demand (BOD).
ABSTRACT
Developing convenient and accurate SARS-CoV-2 antigen test and serology test is crucial in curbing the global COVID-19 pandemic. In this work, we report an improved indium oxide (In2O3) nanoribbon field-effect transistor (FET) biosensor platform detecting both SARS-CoV-2 antigen and antibody. Our FET biosensors, which were fabricated using a scalable and cost-efficient lithography-free process utilizing shadow masks, consist of an In2O3 channel and a newly developed stable enzyme reporter. During the biosensing process, the phosphatase enzymatic reaction generated pH change of the solution, which was then detected and converted to electrical signal by our In2O3 FETs. The biosensors applied phosphatase as enzyme reporter, which has a much better stability than the widely used urease in FET based biosensors. As proof-of-principle studies, we demonstrate the detection of SARS-CoV-2 spike protein in both phosphate-buffered saline (PBS) buffer and universal transport medium (UTM) (limit of detection [LoD]: 100 fg/mL). Following the SARS-CoV-2 antigen tests, we developed and characterized additional sensors aimed at SARS-CoV-2 IgG antibodies, which is important to trace past infection and vaccination. Our spike protein IgG antibody tests exhibit excellent detection limits in both PBS and human whole blood ((LoD): 1 pg/mL). Our biosensors display similar detection performance in different mediums, demonstrating that our biosensor approach is not limited by Debye screening from salts and can selectively detect biomarkers in physiological fluids. The newly selected enzyme for our platform performs much better performance and longer shelf life which will lead our biosensor platform to be capable for real clinical diagnosis usage. Electronic Supplementary Material: Supplementary material (materials and methods for device fabrication, functionalization of In2O3 devices, photographs of the liquid gate measurement setup, mobilities of the nine devices labeled in Fig. 1(b), family curves of I DS-V DS with the liquid gate setup and current change after bubbling the substrate solution (current vs. time curve for S1 antigen detection)) is available in the online version of this article at 10.1007/s12274-022-4190-0.