NANO-MATERIAL-BASED BIOSENSORS FOR THE DETECTION OF ANTIBIOTICS

Abstract

Biosensor development is gaining a lot of attention in the healthcare and biomedical industries. Because of the wide range of biosensor applications such as drug delivery, human health management, patient health monitoring, water, and food quality monitoring, environmental monitoring, disease diagnosis, and, the design and development of biosensors have become a priority for scientists and researchers in the last decade. Electrochemical biosensors and optical biosensors are the most prevalent among the various types of biosensors because of their inexpensive cost, quick response time, mobility, selectivity, and high sensitivity. Nanomaterials have made significant progress in sensing applications in recent years. Nanomaterial-based biosensors have attracted researchers to experiment with new concepts to increase analytical performance. These nanomaterials are widely known for their superior mechanical, catalytic, thermal, optical, and electrical properties, opening many possibilities for nanomaterial-based biosensors and systems. Many different forms of nanomaterials, such as carbon quantum dots (CQDs), nanoparticles (Nps), and their composite, have been used to fabricate nanostructured biosensors for the detection of ciprofloxacin antibiotics. Diverse nanomaterial-based biosensing approaches have recently been established for simple and small analytical instruments for on-site investigation of multiple analytes such as environmental contaminants, disease, toxins, etc. In the present thesis, we have detected Ciprofloxacin antibiotic. Ciprofloxacin belongs to the fluoroquinolones (FQs) class of antibiotics. It is a very stable antibiotic that does not go through complete metabolism in the body, and 30–90% of Ciprofloxacin (CPX) constantly remains. The growing public concern about the accumulation of drug residues in the food supply chain and livestock has led to the general administration of this antibiotic. However, CPX residues have been found to jeopardize people's health by influencing mammalian cell replication and adverse drug reactions. There is a strong probability that it reaches the environment through patient urine samples and wastewater due to inadequate metabolization of CPX in the body, which induces antibiotic resistance. In the coming future, the phenomenon of antibiotic resistance will be more complex. The primary stumbling block is the failure to detect pathogenic bacteria, resulting in inadequate antibiotic use and a lower survival rate in septic situations. As a result, there is an urgent requirement to closely track the use and discharge of these medications in the atmosphere via the human body As a result, sensitive, inexpensive, portable, quick, and selective antibiotic detection is needed and is of great concern. Different analytical methods for determining antibiotics have been developed and used in the past; however, Optical and electrochemical detection approaches have benefits over these techniques in terms of strong selectivity, simple operation, high sensitivity, low cost, speed, and real-time detection with in situ analysis. This thesis is devoted to providing electrochemical and optical biosensing systems for ciprofloxacin detection in milk samples. In this context, we have synthesized two different nanomaterials. First is carbon quantum dots (CQDs) and another one is nanoparticles and their composite. In the CQDs category, two types of CQDs are synthesized from different materials such as C.Tmala (tej patta) leaf extract and Ziziphus mauritiana (ber) by the green route. In the nanomaterial category, we synthesized lanthanum oxide nanoparticles (La2O3)& lanthanum oxide nanoparticles with reduced graphene oxide(La2O3-Rgo).The synthesis of nanoparticles and their nanocomposite was confirmed using different techniques like UltraViolet-Visible spectroscopy (UV- Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman, Atomic force microscopy (AFM), Contact Angle, Scanning electron microscopy (SEM), High resolution-transmission electron microscopy (HR-TEM), etc. along with other electrochemical characterization techniques such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The various nano platform developed in this thesis was fabricated using the electrophoretic deposition technique (EPD) on indium tin oxide (ITO) like BSA/anti-CPX/APTES/nLa2O3Nps/ITO and BSA/anti CPXATPES/nLa2O3-rGONps/ITO substrate. Though BSA/anti-CPX/ATPES/nLa2O3 Nps/ITO showed good electrochemical results, BSA/anti-CPX/ATPES/nLa2O3 rGONps/ITO nano platform displayed excellent performance in terms of a broad linear range from (0.001 ng/mL-1000 ng/mL), having a higher sensitivity of 11.44 μA ng-1m Lcm-2 and a low limit of detection of 0.001 ng/mL. and linear range from 10-6 –600 µg/ mL and sensitivity of 6.52 μA μg-1 mL cm-2 low limit of detection 0.055 µgmL-1 respectively. It also displayed better results in the case of excellent selectivity, repeatability, reproducibility stability, and diffusion coefficient. Moreover, the electrochemical nano platform was productively helpful in analyzing the real samples to detect ciprofloxacin with acceptable results. CQDs from Ziziphus mauritiana (ber) have a good linear range and LOD compares to C. tmala (tej patta) CQDs. The linear range from 10 to 100 µM with a low limit of detection is 0.56 µM and the linear range from 1 to 100 µM with a low limit of detection is 6.06 µM respectively. At last, this thesis also emphasizes the future perspectives for developing biosensors to detect other analytes.