1f:T4d0,As a result of the risks that waterborne bacteria bring to the human body, identifying them in drinking water has become a global concern. In this article, a highly sensitive surface plasmon resonance (SPR) biosensor consisting of prism, Ag, graphene, affinity layer and sensing medium is proposed for rapid detection of the waterborne bacteria. Four SPR-based sensors are first studied with the structures prism/Ag/sensing medium, prism/Ag/affinity layer/sensing medium, prism/Ag/graphene/sensing medium, and prism/Ag/graphene/affinity layer/sensing medium. The latter structure is found to have the highest sensitivity so it is considered for further investigations. Four different commonly used prisms are then demonstrated which are N-FK51A, 2S2G, SF10 and BK7. The structure with the prism N-FK51A is found to correspond to the highest sensitivity so it is considered for further investigations. The structure parameters are then optimized. The proposed SPR sensor can achieve high sensitivity of about 221.63 °/RIU for Escherichia coli and 178.12 °/RIU for Vibrio cholera bacteria with an average value of 199.87 °/RIU. We believe that the proposed structure will open a new window in the field of microorganism detections.20:T4c3,A long-range surface plasmon resonance (LRSPR) sensor with enhanced performance has been theoretically calculated and experimentally investigated for biosensing applications. The LRSPR-based sensor is fabricated by employing a side-polished multimode fiber as a waveguide and MgF ₂ as a buffer layer beneath a thin silver film for supporting LRSPR excitation. Theoretical optimization based on transfer matrix method and the corresponding validation experiments were carried out in detail. The theoretical and experimental results consistently indicate that the sensing performance parameters of the LRSPR-based sensor are improved with varying degrees in comparison to conventional SPR (CSPR) sensors. It was experimentally achieved that the maximal figure of merit of the LRSPR-based sensor exceeds that of the CSPR sensor by a factor of 1.14. At last the bovine serum albumin (BSA) concentration detection was performed to further confirm the sensitivity enhancement of the optimized sensor in biosensing. This SPR sensor design and development is expected to exert a positive influence on real-time and label-free.21:T549,MXene (Ti₃C₂T_x) has emerged very recently as an interacting material for surface plasmon resonance (SPR) configuration. It was discovered that Ti₃C₂T_x can facilitate the adsorption of biomolecules due to its higher binding energies, stronger interaction between matter and light, and larger surface area. In this work, a two-dimensional Ti₃C₂T_x and silicon layer-based SPR refractometric sensor is proposed for the sensitive and fast detection of milk fat concentration due to the high significance of this issue to people all over the world. The proposed SPR structure employs BK7 (BK7 is a designation for the most common Borosilicate Crown glass used for a variety of applications in the visible range) as a coupling prism and silver as a metal layer. The layer thicknesses and the number of Ti₃C₂T_x sheets are optimized for the highest performance. The highest reached sensitivity is 350 deg./RIU with 50 nm silver and 4 nm silicon with a monolayer of Ti₃C₂T_x, which is ultra-high sensitivity compared to the latest work that utilizes SPR configuration. The proposed SPR-based sensor's ultra-high sensitivity makes it more attractive for usage in a variety of biosensing applications.

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