Conference Agenda

Bioluminescent systems possess remarkable features, such as high quantum yield and no need for an external light source, that render them highly valuable bioanalytical tools for developing portable biosensors for monitoring molecules, cells, and bioactivities with applications spanning from agro-food to clinical fields. Therefore, bioluminescent biosensors have a great potential to support the “One Health” approach, to guarantee health to humans, pets, wildlife and our environment.

Here we report the development of novel bioluminescent biosensors implementing living cells and cell-free systems immobilized on paper and cotton threads and interfaced to a smartphone as light detector. The implementation of artificial intelligence algorithms to smartphone-based bioluminescence detection is also reported. A paper-based toxicity smartphone biosensor was developed providing, thanks to an Android AI mobile app, quantitative and user-friendly information.

The combination of bioluminescence biosensing with microfluidic thread-based analytical devices (μTADs) provided a sustainable low-cost alternative to paper based biosensing, especially to handle very low volumes of samples (less than 5 µl). We report a proof-of-principle application of bio-chemiluminescence biosensing on cotton threads and, to prompt future applications in point-of-care and point-of need settings, we exploited smartphone detection enabling easy detection of the bio-chemiluminescent signal directly on the thread.

This study deploys the application of Fiber Bragg Gratings (FBGs) in physiological pressure monitoring by integrating an elastomeric, biocompatible coating ranging from 300-500μm, designed to improve sensor functionality for in-vivo pressure monitoring applications. FBGs are favored for their sensitivity, immunity to electromagnetic interference, and compact size, making them ideal for embedding within medical devices such as catheters and guidewires. However, their use has been limited by low inherent pressure sensitivity (3.14 pm/MPa) and the impracticality of thicker coatings described in previous studies. Our approach demonstrates that this unique coating not only boosts the pressure sensitivity significantly—surpassing two orders of magnitude (43.10 times)—but also enhances the signal-to-noise ratio of the optical signal. These advancements enable potential applications in high-resolution manometry, gastrointestinal pressure monitoring, intracranial and intracoronary blood pressure measurements, marking a significant step forward in medical diagnostics and monitoring.

We discuss the implementation of Whispering Gallery Modes Microbubble resonators (MBRs) as unique platforms for photoacoustic (PA) detection and photothermal (PT) spectroscopy. In a first experiment, the MBR transducer allowed to detect the PA signal generated by a suspension of gold nanorods (GNRs) within its core, leveraging on the MBR sharp optical spectrum and high sensitivity towards mechanical perturbations. Both static and flow-cytometry configuration were tested, finding that the MBR mechanical modes help detection by decoupling the environmental noise from the PA oscillation. In a second experiment, the MBR transducer allowed to reconstruct the GNRs absorption spectrum through the photothermal (PT) conversion, leveraging on high sensitivity towards temperature variations. We verified the scattering-free nature of the detection by using milk-stained GNRs suspension. We also found that the active locking of the MBR resonance increases the system sensitivity by an order-of-magnitude. These results make MBRs interesting candidates for combined PA and PT characterisation of extremely small samples for medical diagnosis, quality controls in food safety and chemical production processes.

A novel technique for the realization of superimposed long-period gratings with different grating periods, based on the discretization of a continuous sinusoidal refractive index pattern with a step function, is described. The RI variation is induced step-by-step on a photosensitive optical fiber fiber with a 248nm UV laser beam. Two superimposed long-period grating (LPGs) with different grating periods, so coupling the light to two different cladding modes, were realized, and different sensitivity to refractive index and temperature were exploited for the simultaneous detection of both parameters. The proposed device can be used for the compensation of temperature fluctuations in biosensing.

Whispering Gallery Modes (WGM) are optical resonators with promising applications in chemical sensing. Nonetheless, only few examples regarding the detection of small molecules through WGM resonators have been reported in the literature to date. Here, we report on the detection of the anticancer drug Doxorubicin (DXR) using Layer-by-Layer (LbL)-functionalized WGM fluorescent microparticles. In particular, polystyrene sulfonate (PSS) is assembled in combination with the polycation polyallylamine hydrochloride (PAH) on the WGM surface and exploited as the DXR receptor. The PSS-functionalized WGM particles feature a linear change of the WGM resonance wavelength and linewidth when exposed to DXR at concentrations down to 1 μg mL-1, with good selectivity against other anticancer drugs. Remarkably, detection of DXR in interstitial fluid is also successfully demonstrated.