A lens-less optical fiber designed for enhanced-fluorescence biosensor applications is presented. In order to obtain the enhanced sensor performances, two elements are essential: a planar antenna that redirects fluorescence emission into a narrow cone and an automated fiber-based optical system for multi-spot analysis. In particular, the potential early diagnosis of sepsis via C-reactive protein (CRP) detection is here demonstrated, reaching a limit of detection of 1.5 ng/mL), which is in the clinical range of interest for such biomarker. Upon the combination with other sepsis biomarkers, the presented sensor can become relevant for the early diagnosis of sepsis. These results validate the developed prototype as a simple, affordable, easy-to-operate, plug&play device with fast turnaround times, compatible with standardized micro-well arrays, and potentially suitable for POC applications with respect to the diagnosis of sepsis. It is also suitable for implementation with other biomarkers and liquid environments.
Esophageal pressure, bile content and pH in the gastroesophageal apparatus are important parameters to be monitored in gastroesophageal diseases. An all-optical device was developed for their simultaneous measurement and utilizes a catheter where plastic optical fibres for the measurement of bile and pH and a glass fibre with FBGs for pressure monitoring are integrated. The interrogation device contains two different modules: one for the pressure monitoring based on the measurement of the wavelength shift of the grating peaks, and the other one for bile and pH measurement, based on absorption changes caused by the esophageal content.
Esophageal pressure, bile content and pH in the gastroesophageal apparatus are important parameters to be monitored in gastroesophageal diseases. An all-optical device was developed for their simultaneous measurement and utilizes a catheter where plastic optical fibres for the measurement of bile and pH and a glass fibre with FBGs for pressure monitoring are integrated. The interrogation device contains two different modules: one for the pressure monitoring based on the measurement of the wavelength shift of the grating peaks, and the other one for bile and pH measurement, based on absorption changes caused by the esophageal content.
Sepsis, defined as the systemic inflammatory response to a confirmed or suspected source of infection, is the most severe infection-related condition and its identification can be particularly difficult in the initial stages. The importance of having a Point-of-care testing platform capable of measuring sepsis biomarkers for a secure early-stage diagnosis is evident to reduce delay in treatment and hence recovery period for the patient.
We will report on a simple and cost-effective device which also shows high portability. It is based on the optical detection of labeled essays through a fully-automated fiber probe. Efficient signal collection is obtained by replacing the standard glass substrate with a planar metallo-dielectric multilayer which funnels the emission into a narrow cone around the polar axis [1]. Optical interrogation is implemented with a minimized epi-fluorescence monolithic system directly connected to the fiber.
On one hand, optical probes provide the ability to detect low quantities of target molecules without direct contact to the sample; on the other hand, nano-photonics promises to overcome the limitations related to bulk optics with precise and fragile alignment procedures.
We will report on preliminary results obtained for a reference dry essays (IgG/anti-IgG) marked with ATTO647N, which demonstrates sensitivity overcoming the requirements for CRP-based sepsis detection. We will also discuss optimization steps which are expected to bring sensitivity beyond the level required for PRC-based sepsis detection. The proposed device is also prone to implementation in microfluidic-based protocols.
[1] Checcucci S, Lombardi P., Rizvi S., Sgrignuoli F., Gruhler N., Dieleman F.B.C., Cataliotti F.S., Pernice W.H.P., Agio M., and Toninelli C., Beaming light from a quantum emitter with a planar optical antenna, Light: Science and Applications, Vol. 6, e16245 (2017).
Sepsis, defined as the systemic inflammatory response to a confirmed or suspected source of infection, is the most severe infection-related condition and its identification can be particularly difficult in the initial stages. The importance of having a POCT platform capable of measuring sepsis biomarkers for a secure early-stage diagnosis is evident since traditional methods of pathogen determination delay treatment and also increase the recovery period for the patient. The biggest advantage of optical probes is the ability to detect low quantities of target molecules without direct contact to the sample. Nanophotonics-based sensing promises to build on the advantages of optical sensing, while overcoming its limitations by providing a high sensitivity, specificity, dynamic range, as well as the possibility for easy integration into simple and affordable devices. The project FASPEC (Fiber-based planar antennas for biosensing and diagnostics) aims at developing and prototyping a high-performance fluorescence-based molecular assay for in-vitro diagnostics that integrates lab-on-a-chip and optical readout functionalities within a single, fully automated platform. The key biophotonics innovation of the project is the replacement of the bulk optics used for collecting the fluorescence signal with a suitably designed optofluidic chip. The latter shall function as an optical antenna to direct fluorescence towards the sensor head, hence enhancing the sensitivity of the fluorescence-based assay by orders of magnitude. Application-specific lab-on-a-chip systems equipped with our high-throughput and ultrasensitive detection scheme have been envisioned.
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