In the proposed work, a highly sensitive reduced graphene oxide (rGO) coated etched fiber Bragg grating (eFBG) pH sensor is developed and characterized. To create the sensing probe, a nanocomposite layer of rGO is coated over the unclad area of the eFBG. The analysis of rGO material has been done using different characterization tools such as UV-VIS-NIR spectroscopy, x-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM). Experiments are performed using pH samples ranging from pH 2 to pH 12 to validate the operational sensing range of the proposed sensor. The effectiveness of the proposed sensor is evaluated with various pH values by monitoring the shift in the resonance peak of the sensor's reflection spectrum in a real-time interrogation system. The sensor performs well in both low and high pH ranges, with a maximum sensitivity of 0.232 nm/pH at pH 12. Due to a shift in the rGO's optical band-gap at both low and high pH values in the samples, the sensor can detect minimal changes in concentration. In the reflected spectrum, the Bragg wavelength (λ B) shifts as a result of the change in the refractive index. The λ B is observed to change as the pH of the aqueous solution is changed experimentally. Its performance is shown to be minimally affected by the ambient temperature (in the range of 19-21∘ C). The sensor also has the capacity for remote sensing, a quick response time, a small size, a low cost, a miniaturized probe, and the ability to reuse the probe.
Food safety is a scientific discipline that requires sophisticated handling, production, and storage. Food is common for microbial development; it acts as a source for growth and contamination. The traditional procedures for food analysis are time-consuming and labor-intensive, but optical sensors overcome these constraints. Biosensors have replaced rigorous lab procedures like chromatography and immunoassays with more precise and quick sensing. It offers quick, nondestructive, and cost-effective food adulteration detection. Over the last few decades, the significant spike in interest in developing surface plasmon resonance (SPR) sensors for the detection and monitoring of pesticides, pathogens, allergens, and other toxic chemicals in foods. This review focuses on fiber-optic SPR (FO-SPR) biosensors for detecting various adulterants in food matrix while also discussing the future perspective and the key challenges encountered by SPR based sensors.
Biosensing Techniques , Surface Plasmon Resonance , Surface Plasmon Resonance/methods , Biosensing Techniques/methods , Fiber Optic Technology/methods , Food Contamination/analysis
Surface Plasmon Resonance (SPR) techniques are highly accurate in detecting biomolecular like blood group measurement, food adulteration, milk adulteration and recently developing as a rapid detection for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. In order to validate the clinical diagnosis, Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) of nasopharyngeal swabs has been utilized, which is time consuming and expensive. For fast and accurate detection of the SARS-CoV-2 virus, SPR based biosensing chips are described in this review article. SPR sensors have the potential to be employed for fast, accurate, and portable SARS-CoV-2 virus diagnosis. To combat the SARS-CoV-2 pandemic, there is considerable interest in creating innovative biosensors that are quick, reliable, and sensitive for COVID-19 diagnosis.
