Fiber optic sensors have gained popularity over the last few decades. This is due to their numerous advantages, such as good metrological parameters, biocompatibility and resistance to magnetic and electric fields and environmental pollution. However, those built from glass fiber have one main disadvantage—they are fragile, meaning they can be easily damaged, even by the presence of vibration. Due to the great progress made by material research recently, it is possible to build such a sensor with polymer fibers instead. Although those fibers have worse transmission parameters compared to telecommunication fibers, they provide the possibility to realize flexible fiber optic sensors. Taking into consideration other advantages of such fibers, including biocompatibility, electromagnetic resistance and even, biodegradation characteristics, as well as there being a variety of materials we can use, it can be seen that those materials are beneficial to produce fiber optic sensors. This paper aims to provide researchers with guidelines on the factors to consider when choosing a material for bent fiber optic sensors, depending on the application.

SignificanceBiophotonics has advanced through many discoveries, yet challenges remain, including label-free biomolecular specificity, quantitative imaging, and single-molecule detection. Progress is further constrained by the need for cheaper, lighter, miniaturized materials that still meet strict optical, electrical, and mechanical specifications. This limitation can be overcome if bioinspired structures are developed. One of the developed areas in which solutions in nature are used is micro and nanostructures including nanosurfaces. It offers a way to increase biomolecular specificity and develop lightweight, low-cost devices for biomedicine. However, it requires measuring phenomena in materials and testing these materials in applications, e.g., sensing systems.AimWe offer a concise, authoritative overview of biophotonics—from nanoscale light–biomolecule interactions to bioinspired materials, phantoms, test methods, and sensor development.ApproachA coherent and comprehensive analysis of the crucial problems related to the development of bioinspired materials and devices was carried out. Recent advances in light scattering by biological surfaces enable structure characterization, disease diagnosis, red-blood-cell analysis, drug discovery, and optical imaging and sensing. Structural and genetic bases of biological photonic surfaces were examined, alongside key performance factors in bio-inspired materials—biocompatibility, biodegradability, structure-optics coupling (e.g., dynamic color change), and scalability limits. We survey chiral nanomaterials, silica frustules, and artificial surfaces that emulate peacock feathers, butterfly wings, iridescent fruits, plant petals, and beetle cuticles, highlighting complementary diagnostics—omics, hyperspectral, and terahertz imaging—for structural analysis and material innovation. We examine bio-inspired phantoms for medical calibration, recent advances in Monte Carlo tissue light-transport modeling, and the resulting applications of these materials and diagnostic tools.ResultsResults confirm a broad set of tunable bio-inspired materials: key optical phenomena were mapped, structures fabricated and modeled, phantoms validated, and strong sensor potential demonstrated.ConclusionsWe survey emerging biophotonics, review material and system requirements, and emphasize simplifying and miniaturizing sensors for biomedical use.

This study introduces a fiber‐optic sensor functionalized with a sensing probe for SARS‐CoV‐2 RNA detection. The sensor employs a microsphere design at the sensor's tip, enhanced with a gold layer and oligonucleotide probes, to achieve high sensitivity and specificity. Utilizing optical interference, the system enables near real‐time monitoring of viral RNA at concentrations as low as 10⁻¹² M. While the sensor's sensitivity is lower than that of the RT‐PCR, it excels in speed, portability, and scalability, making it suitable for point‐of‐care diagnostics, environmental monitoring, and large‐scale screening. The integration of fiber‐optic sensors with advanced analytical systems further enhances their utility in preventing virus transmission and contamination, highlighting their role in global efforts to combat infectious diseases.

A simple urine phantom was developed to replicate the ultraviolet–visible (UV–Vis) spectrum of healthy human urine. Made from four safe and widely available ingredients, it addresses the challenges of biological samples, including safety risks and storage issues. The spectroscopic analysis results confirmed strong similarity to natural urine, making the phantom appropriate for testing spectroscopic methods, calibrating optical devices, and evaluating diagnostic sensors. It can also serve as a starting point for advanced phantoms tailored to specific patient needs or diseases. This reliable alternative facilitates research in optical diagnostics or biosensor development by simplifying preliminary sensor testing.

Rapid and accurate detection is crucial for pandemic surveillance and global public health management. However, conventional methods are often limited by time-consuming sample preparation procedures and delayed readout. Here, we present an ultrafast, label-free photonic biosensing platform for the direct detection of viral RNA in complex matrices, such as wastewater. The platform is based on a biofunctionalized microsphere fabricated from a standard telecommunication optical fiber and enables the direct detection of synthetic DNA specifically designed to mimicking selected fragments of influenza A viral RNA, without prior isolation or amplification. Its performance was validated in phosphate-buffered saline and further evaluated in untreated wastewater samples spiked with influenza A viral RNA sequence under laboratory conditions. The platform successfully detected viral RNA at the lowest tested concentration of 0.1 fM, enabled detection across the tested concentration range of 0.1-1000 fM, and provided a response within 5 s from sensing probe immersion to signal readout. These proof-of-concept results highlight the potential of the proposed platform for real-time viral RNA monitoring in complex matrices and its future application in wastewater-based epidemiology.

In this article, the refractive index of an egg white and yolk depending on temperature in range 30 - 47 °C over 1550 nm was determined. The measurement head was constructed as fiber optic Fabry-Perot interferometer with interference between polished fiber end-face and aluminum weighing dish. The measurement setup has been made of an optical spectrum analyzer, a superluminescent diode with a central wevelength of 1550 nm, 2:1 fiber coupler and heat plate. Full Text: PDF ReferencesP. Magdelaine, "Egg and egg product production and consumption in Europe and the rest of the world, Improving the Safety and Quality of Eggs and Egg Products", Egg Chemistry, Production and Consumption, 3 (2011). CrossRef H. Kuang, F. Yang, Y. Zhang, T. Wang, and G. Chen, "The Impact of Egg Nutrient Composition and Its Consumption on Cholesterol Homeostasis", Cholesterol (2018). CrossRef J. Gienger, K. Smuda, R. Müller, M. Bär, and J. Neukammer, "Refractive index of human red blood cells between 290 nm and 1100 nm determined by optical extinction measurements", Sci. Rep. 9, 1 (2019). CrossRef P. Listewnik, M. Hirsch, P. Struk, M. Weber, M. Bechelany, and M. Jędrzejewska-Szczerska, "Preparation and Characterization of Microsphere ZnO ALD Coating Dedicated for the Fiber-Optic Refractive Index Sensor", Nanomaterials 9, 2 (2019) CrossRef Y. Wu, Y. Zhang, J. Wu, and P. Yuan, "Fiber-Optic Hybrid Structured Fabry-Perot Interferometer Based On Large Lateral Offset Splicing for Simultaneous Measurement of Strain and Temperature", J. Lightwave Technol., 35, 19 (2017). CrossRef M. Islam, M. Mahmood, M Lai, K. Lim, and H. Ahmad, "Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review", Sensors 14, 4 (2014). CrossRef K. Karpienko, M. Wróbel, and M. Jędrzejewska-Szczerska, "Determination of refractive index dispersion using fiber-optic low coherence Fabry-Perot interferometer: implementation and validation", Opt. Eng. 53, 7 (2014). CrossRef M. Kosowska, D. Majchrowicz, K. Sankaran, M. Ficek, K. Haenen, and M. Szczerska, "Doped Nanocrystalline Diamond Films as Reflective Layers for Fiber-Optic Sensors of Refractive Index of Liquids", Materials 12, 13 (2019). CrossRef G. Xiao, A. Adnet, Z. Zhang, F. Sun, and C. Grover, "Monitoring changes in the refractive index of gases by means of a fiber optic Fabry-Perot interferometer sensor", Sensors and Actuators 118, 2 (2005). CrossRef