Ambra Giannetti

Italian National Research Council | CNR · Institute of Applied Physics "Nello Carrara" IFAC

Maintaining both high sensitivity and large figure of merit (FoM) is crucial in regard to the performance of optical devices, particularly when they are intended for use as biosensors with extremely low limit of detection (LoD). Here, a stack of nano‐assembled layers in the form of 1D photonic crystal, deposited on D‐shaped single‐mode fibers, is c...

As the population ages, the worldwide prevalence of Alzheimer's disease (AD) as the most common dementia in the elderly is increasing dramatically. However, a long‐term challenge is to achieve rapid and accurate early diagnosis of AD by detecting hallmarks such as amyloid beta (Aβ42). Here, a multi‐channel microfluidic‐based plasmonic fiber‐optic b...

Advantages of biosensors based on surface enhanced Raman scattering (SERS) rely on improved sensitivity and specificity, and suited reproducibility in detecting a target molecule that is localized in close proximity to a SERS-active surface. Herein, a comprehensive study on the realization of a SERS biosensor designed for detecting miRNA-183, a miR...

In today’s medicine, the celerity of the bio-assays analysis is crucial for the timely selection of the appropriate therapy and hence its effectiveness, especially in case of diseases characterized by the late onset of symptoms. In this paper, a lens-less fiber optics-based fluorescence sensor designed for the measurement of labeled bio-assays is p...

A methodology to enhance the sensitivity of long-period fiber gratings (LPFGs) based on the combination of three different enhancement approaches is presented; the methods here adopted are the working near mode transition (MT) of a cladding mode (CM), working near the turn-around point of a CM and the enhancement of the evanescent field of CMs by r...

Alzheimer’s disease (AD) is one of the most common neurodegenerative illnesses displaying the highest death rate in old persons. However, the existing AD diagnostic system remains elusive due to lack of a technology that may ensure enough sensitivity and reproducibility, detection accuracy and specificity. Here we report a straightforward approach...

A long period fiber grating was fabricated, characterised by the maximum enhancement of the evanescent field by means of the exploitation the lowest order LP0,2 cladding mode (CM) near turn-around point (TAP) in water medium. A thermostated closed flow cell was designed for sensor characterization and immunoassay implementation. The sensor was char...

A new methodology to enhance the sensitivity of a long period fiber grating sensor (LPFG) at the turn around point (TAP) is here presented. The LPFG sensor has been fabricated by etching the fiber up to 20.4 μm, until the sidelobes of dispersed LP0,2 cladding mode appeared near TAP in aqueous medium. The dual peak sensitivity of the sidelobes was f...

Cardiac hypertrophy, in its aspects of localized thickening of the interventricular septum and concentric increase of the left ventricle, constitutes a risk factor of heart failure. Myocardial hypertrophy, in the presence of different degree of myocardial fibrosis, is paralleled by significant molecular, cellular, and histological changes inducing...

Fiber optics as a special class of guided-wave optics represents a promising, effective and high-performance tool to develop a biosensor with high sensitivity and low limit of detection in the measurement of refractive index changes.

The present paper describes a compact point of care (POC) optical device for therapeutic drug monitoring (TDM). The core of the device is a disposable plastic chip where an immunoassay for the determination of immunosuppressants takes place. The chip is designed in order to have ten parallel microchannels allowing the simultaneous detection of more...

The determination of per- and polyfluoroalkyl substances (PFAS) in environmental samples, such as drinking waters, requires the design of high performing and versatile sensing strategies. Label-free biosensing platforms based on specialty fiber optics are a valid option to face this challenge. Among them, lossy mode resonance (LMR) fiber optic bios...

In this work we report about a novel label-free biosensing configuration consisting of a long period grating (LPG) inscribed into a double cladding fiber (DCF) and coated with a thin layer of graphene oxide (GO). The DCF had a W-type refractive index (RI) profile and permitted the tuning of the device working point to the mode transition region thr...

A long period fiber grating has been fabricated by combining two sensitivity enhancement techniques, the turn around point (TAP) and the maximum enhancement of the evanescent field by obtaining the lowest order cladding mode (LP0,2 cladding mode). A label-free immunoglobulin G/anti immunoglobulin G (IgG/anti-IgG) immunoassay in serum has been perfo...

Ion-exchange in molten nitrate salts containing metal ions (i.e. silver, copper, etc.) represents a well-established technique able to modify the chemical-physical properties of glass materials. It is widely used not only in the field of integrated optics (IO) but also, more recently, in plasmonics due to the possibility to induce the formation of...

In this work, an unconventional light-diffusing fiber (LDF) plasmonic platform is exploited to efficiently monitor a bio-interaction. The surface plasmon resonance (SPR)-LDF sensor is used to detect the immunoglobulin G (IgG)/anti-IgG interaction as exemplifying bioassay. The IgG bioreceptor was deposited on the gold surface of the SPR-LDF platform...

Aptamers are the evidence of the power and versatility of DNA. In the biosensing field, if the important properties of aptamers together with all the many different conformations they can adopt are coupled to the proper transduction system, an unthinkable amount of possibilities is open up to construct biosensing methods for, in principle, any imag...

In this work, the development and testing of a novel fiber-optic based label-free biosensor is presented, whose performance were verified through the detection of C-reactive protein (CRP) in serum. The device is based on a long period grating fabricated in a double cladding fiber with a W-shaped refractive index (RI) profile. As a result, the worki...

The combination of fiber optic devices with nanotechnology permits to realize sensing platforms with remarkable performance. Lossy mode resonance (LMR), a very promising phenomenon, allows detecting analyte concentrations in the femtomolar range with sensational perspectives.

The study of cell activities, monitoring specific molecule behaviors, is of crucial importance for the deepening of the knowledge of cellular mechanisms. For this reason, the demand of biosensing probes capable to enter living cells and to be localized in definite cellular compartments is becoming more and more important. The intracellular biosensi...

Objectives Therapeutic drug monitoring (TDM) plays a crucial role in personalized medicine. It helps clinicians to tailor drug dosage for optimized therapy through understanding the underlying complex pharmacokinetics and pharmacodynamics. Conventional, non-continuous TDM fails to provide real-time information, which is particularly important for t...

Here, we have reported the development and testing of a label-free fiber optic biosensor, for the real-time detection in serum of an inflammatory marker, the C-reactive protein (CRP). It is based on a novel configuration involving a long period grating (LPG) in double cladding fiber, with specific refractive index profile. Optimization of the sensi...

A long-period fiber grating (LPFG) with maximum enhancement of evanescent field has been designed and fabricated, along with theoretical modeling, by working near the turn-around point (TAP) of the lowest order symmetric cladding mode (LP0.2 cladding mode). The LPFG was fabricated using a point-by-point inscription technique and it was characterize...

This chapter focuses on optical fibre sensors (OFSs) that measure refractive index (RI) changes as main sensing mechanism. It analyzes the basic sensing concepts and parameters that can be used to assess the performance of OFSs. The chapter discusses optical fibre refractometers, where the RI changes encompass all the volume around the fibre, and o...

Optical fibre micro/nano tips (OFTs), defined here as tapered fibres with a waist diameter ranging from a few microns to tens of nanometres and different tip angles (i.e., from tens of degrees to fractions of degrees), represent extremely versatile tools that have attracted growing interest during these last decades in many areas of photonics. The...

A long period fiber grating (LPFG) sensor has been fabricated, after theoretical analysis, obtaining the maximum enhancement of the evanescent field working with the lowest order cladding mode (LP0,2 cladding mode) near turn around point. Both the wavelengths of the dual peak resonance and the coupling conditions of the mode have been analyzed in d...

Water pollution is a severe worldwide problem that urgently requires development of novel sensing concepts allowing for monitoring in situ a variety of contaminants at very low concentrations in a cost-effective and multiplexed format. Whispering Gallery Mode (WGM) resonators represent novel and promising tools for the development of high-performan...

Chemiluminescence (CL) detection is widely employed in biosensors and miniaturized analytical devices since it offers high detectability and flexible device design (there are no geometry requirements for the measurement cell, except the ability to collect the largest fraction of emitted photons). Although the emission anisotropy phenomenon for an e...

The combination of optical fibre-based biosensors with nanotechnologies is providing the opportunity for the development of in situ, portable, lightweight, versatile and high-sensitivity optical sensing platforms. We report on the generation of lossy mode resonances (LMRs) by means of the deposition of nm-thick SnO2 film on optical fibres. This all...

Severe infection and sepsis are a common, expensive, and frequently fatal conditions in critically ill patients. The sepsis diagnosis is not trivial, since it is an extremely complex chain of events involving inflammatory and anti-inflammatory processes, cellular reactions, and circulatory disorders. For these reasons, delay in diagnosis and initia...

Bio-chemical sensing applications are usually performed in water or buffer solution where a conventional long period fiber grating (LPFG) has low sensitivity. For this purpose, it is necessary to enhance the sensitivity of LPFGs within this refractive index (RI) region. Different optimization methodologies are here described and three experimental...

The excitation of lossy mode resonance (LMR) in guided-wave optics is explored. Side-polished fibers underpin the LMR phenomenon with outstanding performance in biosensing applications. Limit of detection of the order of femtomolar has been demonstrated.

The combination of fiber-optic–based platforms for biosensing with nanotechnologies is opening up the chance for the development of in situ, portable, lightweight, versatile, reliable and high-performance optical sensing devices. The route consists of the generation of lossy mode resonances (LMRs) by means of the deposition of nm-thick absorbing me...

D-dimer is a useful diagnostic biomarker for deep vein thrombosis or pulmonary embolism, collectively referred to as venous thromboembolism (VTE). The ability to detect in real-time the amount of D-dimer with a fast and reliable method is a key step to anticipate the appearance of these diseases. Here, the results of a highly specific and sensitive...

Purpose In this exploratory study we investigated the potentiality of radiomic features extracted from multi-parametric magnetic resonance imaging (mp-MRI), as a tool to quantify tumour phenotypic characteristics in Prostate Cancer (PCa) [1]. Methods and materials A retrospective cohort of about 20 PCa patients who underwent a 1.5 Tesla mp-MRI was...

Polymethylmethacrylate core-shell fluorescent nanoparticles promote, in human lung A549 cancer cells, the internalization of a molecular beacon (MB) specific for survivin mRNA, an anti-apoptotic protein overexpressed in cancer cells. Aims To design an effective drug delivery system, the knowledge of the uptake mechanism and of the nanoparticles (N...

Filtering strategies are a crucial aspect for signal detection in many fluorescence based systems such as chemical and/or biochemical sensors. Here we present the design, fabrication and characterization of a new waveguide absorption filter capable of maximizing the fluorescence signal collection thanks to its high numerical aperture. The compariso...

The advent of optical fibre-based biosensors combined with that of nanotechnologies has provided an opportunity for developing in situ, portable, lightweight, versatile and high-performance optical sensing platforms. We report on the generation of lossy mode resonances by the deposition of nm-thick metal oxide films on optical fibres, which makes i...

Colorectal cancer (CRC) is one of the major causes of cancer-associated mortality worldwide. The currently approved therapeutic agents show a rather limited efficacy. We have recently demonstrated that the atypical cadherin FAT1 is a specific marker of CRC and that the FAT1-specific monoclonal antibody mAb198.3 may offer new therapeutic opportuniti...

In this paper, the electronic transduction of DNA hybridization is presented by coupling organic charge-modulated field-effect transistors (OCMFETs) and hairpin-shaped probes. These probes have shown interesting properties in terms of sensitivity and selectivity in other kinds of assays, in the form of molecular beacons (MBs). Their integration wit...

We report on ultra-low detection limit lossy mode resonance-based fibre-optic biosensor coated with nm-thick tin dioxide film, which allows measuring fibre-surrounding medium changes with very high sensitivity for label-free and real-time biomolecular interaction analysis.

In this paper, a detailed investigation on the modeling of long-period fiber grating (LPFG) sensors is discussed with the aim of providing a more realistic solution for their use in biosensing. Add-layer sensitivity, i.e., sensitivity of the sensor to an additional layer adhered onto the fiber surface, is quantified and a clear and complete analysi...

The activity developed at the Institute of Applied Physics “Nello Carrara” in strict collaboration with physicians is described with particular attention to the measurement of bile-containing refluxes in the gastroesophageal apparatus, to the detection of gastric carbon dioxide in intensive care patients, to the measurement of sepsis biomarkers in...

In this paper we report on the application of over coupled long period fibre gratings (OCLPFGs) for detecting small changes in the surrounding refractive index (SRI). In addition, the optimization of a high RI (HRI) overlay deposited over the fibre for the adhesion of biological species is described. In this study, we utilised a sol-gel-based silic...

Infectious diseases and sepsis, as a severe and potential medical condition in which the immune system overreacts and finally turns against itself, are a worldwide problem. As a matter of fact, it is considered the main cause of mortality in intensive care. For such a pathology, a timely diagnosis is essential, since it has been shown that each hou...

Optical fiber gratings (OFGs), especially long period gratings (LPGs) and etched or tilted fiber Bragg gratings (FBGs), are playing an increasing role in the chemical and biochemical sensing based on the measurement of a surface refractive index (RI) change through a label-free configuration. In these devices, the electric field evanescent wave at...

A novel therapeutic drug monitoring point of care testing (POCT) optical device for the detection of immunosuppressants in transplanted patients was designed and tested, with the body interface constituted by an intravascular microdialysis catheter (MicroEye®) which provides the dialysate as clinical sample. An optical biochip with 10 microchannels...

The last twenty years have seen the increasing demand by physicians of devices able to carry out fast and reliable measurements of chemical and biochemical parameters beside the patient’s bed so as to allow the formulation of a rapid and reliable diagnosis and/or the choice of the most appropriate therapy, avoiding the need for analysis of centrali...

The aim of this report is to describe and explore the potential of Radiomics in the framework of the activities developed at the “Nello Carrara” Institute of Applied Physics (IFAC), which is part of the National Research Council (CNR), in collaboration with USL Toscana Centro. The possibility of a more quantitative study of imaging data emerged du...

The design of Whispering Gallery Mode Resonators (WGMRs) used as an optical transducer for biosensing represents the first and crucial step towards the optimization of the final device performance in terms of sensitivity and Limit of Detection (LoD). Here, we propose an analytical method for the design of an optical microbubble resonator (OMBR)-bas...

A procedure for a spatially selective immobilization of antibodies, via photochemical activation, on the inner surface of optical microbubble resonators (OMBRs) is reported. The method is based on a suitable UV mask process. As proof of concept of this technique, immunoassay in photo-activated OMBR was implemented and fluorescence investigation was...

This work shows the improvements in the sensing capabilities and precision of an Optical Microbubble Resonator due to the introduction of an encaging poly(methyl methacrylate) (PMMA) box. A frequency fluctuation parameter σ was defined as a score of resonance stability and was evaluated in the presence and absence of the encaging system and in the...

The first example of an optical sensor platform based on surface plasmon resonance (SPR) in a plastic optical fiber (POF) integrated into a thermo-stabilized flow cell for biochemical sensing applications is proposed. In this work, an IgG/anti-IgG assay was implemented as model bioassay, with the IgG biolayer deposited on the sensor gold surface an...

The integration of the Whispering Gallery Modes (WGMs) resonators in a microfluidics platform represents an important feature towards the realization of a compact high performance label-free biosensor. These hollow resonant microstructures present the advantage to combine the WGM resonator properties with the intrinsic capability of integrated micr...