Małgorzata Szczerska

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.

Phosphorene is a 2D layered material characterized by exceptional properties that open new opportunities for electronic applications. However, its usage is limited due to the rapidly progressing degradation process under ambient conditions. In this study, we present a simple and scalable strategy for few‐layer black phosphorus (FLBP) protection with a cellulose nitrate‐based coating. The FLBP is structurally and morphologically characterized by Raman spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Atomic Force Microscopy. The FLBP stability with and without nitrocellulose‐based protection is evaluated using optical interferometry, surface profilometry, and electrical conductivity measurements under ambient conditions. The results demonstrate that the nitrocellulose coating effectively preserves the optical and electrical properties of FLBP films over time, highlighting its potential for practical device‐oriented applications.

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.

Summary: Reliable and reproducible measurement of spatial resolution is essential for validating and comparing the performance of two-photon microscopy systems. We present fluorescent nanodiamonds as robust, photostable, reusable, and biocompatible probes for benchmarking spatial resolution. Owing to their nanoscale dimensions and stable fluorescence, nanodiamonds act as near-ideal point-like emitters, enabling accurate characterisation of the point spread function across varying imaging conditions. We demonstrate that nanodiamond-based phantoms serve as a reliable alternative to conventional fluorescent beads embedded in agarose, while at the same time offering advantages in stability and optical properties. Our results position nanodiamond phantoms as a next-generation calibration material that bridges ease of use and reproducibility, advancing quantitative imaging and cross-platform comparability in modern fluorescence microscopy.

Wear monitoring in tribological systems is advanced here through an interpretable framework that combines fiber-optic sensing, fuzzy logic, and benchmark machine learning. Authors present a methodology for classifying material wear into four discrete levels (0-3) with micrometer-scale sensitivity using spectral data acquired from a fiber-optic interferometric sensor. From an initial pool of 52 spectral descriptors, nine features were selected and used both to construct an interpretable Mamdani fuzzy expert system with 17 expert-defined rules and to train conventional machine learning classifiers, including Random Forest, Extra Trees, Logistic Regression, and XGBoost. Using stratified 5-fold cross-validation and a held-out test set of 22 spectra from a total dataset of 110 samples, the fuzzy expert system achieved 81.8% accuracy, 85.7% balanced accuracy, and a macro-F1 score of 0.84. Among the evaluated machine-learning baselines, ExtraTreesClassifier was the strongest data-driven model reaching 81.8% accuracy, 83.3% balanced accuracy, and a macro-F1 score of 0.83. All evaluated models outperformed the dummy baseline, while the fuzzy system provided a fully transparent decision-making process by linking spectral patterns to wear states through explicit linguistic rules. Its sub-millisecond inference time (0.010 ms per sample) also supports real-time deployment. These results demonstrate that expert-driven explainable AI can achieve competitive predictive performance in tribology without sacrificing transparency, making the proposed framework a promising solution for trustworthy predictive maintenance in industrial environments.

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.

Research trends are focused on developing solutions that monitor public health utilizing sewage surveillance, as wastewater can provide valuable information on the presence of specific biomarkers. Such information can serve as an indication of immune response at the community level, delivering a noninvasive measure of e.g., vaccination effectiveness. In this paper, we present an optical wastewater phantom fabrication, characterization, and comparison to real wastewater samples. Raman spectroscopy was used for the investigation of the molecular compositions of treated wastewater and artificial wastewater phantoms, and the refractometer to investigate refractive index values dependence on temperature. Selected biomarkers concentrations (10 ⁻⁶ to 10 ⁻¹ mg/mL) were added to the validated phantoms. The selective detection of SARS‐CoV‐2 immunoglobulin G (IgG) was achieved through specific surface modification of the fiber‐optic probe, allowing only targeted biomarkers to attach and influence the measurement signal. Successful detection of 10 ⁻⁶ mg/mL IgG concentration in the wastewater phantom was achieved within 5 min.

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.

Few-layer black phosphorus (FLBP) degrades rapidly in ambient conditions, hindering its practical applications. We demonstrate that a nitrocellulose encapsulation film enables real-time optical monitoring of FLBP while protecting it from degradation. Optical transmission measurements performed over 3 hours confirm the stability of encapsulated samples compared to unprotected references. This approach enables the integration of FLBP in photonic devices under ambient conditions.