This review presents an overview of “Lab on Fiber” technologies and devices with special focus on the design and development of advanced fiber optic nanoprobes for biological applications. Depending ...on the specific location where functional materials at micro and nanoscale are integrated, “Lab on Fiber Technology” is classified into three main paradigms: Lab on Tip (where functional materials are integrated onto the optical fiber tip), Lab around Fiber (where functional materials are integrated on the outer surface of optical fibers), and Lab in Fiber (where functional materials are integrated within the holey structure of specialty optical fibers).
This work reviews the strategies, the main achievements and related devices developed in the “Lab on Fiber” roadmap, discussing perspectives and challenges that lie ahead, with special focus on biological sensing applications.
The Lab on Fiber Technology arises from the judicious synergy of forefront Key Enabling Technologies such as Photonics and Nanotechnology. This work reviews the strategies, the main achievements and related devices developed in the “Lab on Fiber” roadmap, by classifying this paradigm according to the specific location where functional materials are integrated, in Lab on Tip, Lab around Fiber and Lab in Fiber.
The integration of microfluidics and photonic biosensors has allowed achievement of several laboratory functions in a single chip, leading to the development of photonic lab-on-a-chip technology. ...Although a lot of progress has been made to implement such sensors in small and easy-to-use systems, many applications such as point-of-care diagnostics and
in vivo
biosensing still require a sensor probe able to perform measurements at precise locations that are often hard to reach. The intrinsic property of optical fibers to conduct light to a remote location makes them an ideal platform to meet this demand. The motivation to combine the good performance of photonic biosensors on chips with the unique advantages of optical fibers has thus led to the development of the so-called lab-on-fiber technology. This emerging technology envisages the integration of functionalized materials on micro- and nano-scales (
i.e.
the labs) with optical fibers to realize miniaturized and advanced all-in-fiber probes, especially useful for (but not limited to) label-free chemical and biological applications. This review presents a broad overview of lab-on-fiber biosensors, with particular reference to lab-on-tip platforms, where the labs are integrated on the optical fiber facet. Light-matter interaction on the fiber tip is achieved through the integration of thin layers of nanoparticles or nanostructures supporting resonant modes, both plasmonic and photonic, highly sensitive to local modifications of the surrounding environment. According to the physical principle that is exploited, different configurations - such as localized plasmon resonance probes, surface enhanced Raman scattering probes and photonic probes - are classified, while various applications are presented in context throughout. For each device, the surface chemistry and the related functionalization protocols are reviewed. Moreover, the implementation strategies and fabrication processes, either based on bottom-up or top-down approaches, are discussed. In conclusion we highlight some of the further development opportunities, including lab-in-a-needle technology, which could have a direct and disruptive impact in localized cancer treatment applications.
The integration on the optical fiber tip of nanostructures supporting resonant modes highly sensitive to local modifications of the surrounding environment allows the development of lab-on-fiber based biosensors.
Smart Optical Catheters for Epidurals Carotenuto, Benito; Ricciardi, Armando; Micco, Alberto ...
Sensors,
06/2018, Letnik:
18, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Placing the needle inside the epidural space for locoregional anesthesia is a challenging procedure, which even today is left to the expertise of the operator. Recently, we have demonstrated that the ...use of optically sensorized needles significantly improves the effectiveness of this procedure. Here, we propose an optimized configuration, where the optical fiber strain sensor is directly integrated inside the epidural catheter. The new design allows the solving of the biocompatibility issues and increases the versatility of the former configuration. Through an in vivo study carried out on a porcine model, we confirm the reliability of our approach, which also opens the way to catheter monitoring during insertion inside biological spaces.
Optical fibers and lenses are key components in many optical systems. Lenses used to couple light into the fiber or to tailor the output beam coming out from the fiber itself typically involve bulk ...optical schemes and complex packaging that limit the compactness and flexibility of the overall system. In the last years, new technological solutions based on the lab-on-fiber technology have been proposed to directly integrate optical components on the fiber end-face with a monolithic approach. In this review, we provide a detailed state of the art of the miniaturized lenses integrated on the end-face of optical fibers reported so far. The proposed devices have been divided into three main categories (refractive, diffractive and resonant including metasurfaces) according to their working principle. A critical discussion on the different categories of lenses is given, also providing a comparison in terms of ease of design and fabrication, application flexibility, compactness, scientific and technological maturity, and time to market.
Sensing schemes based on Rayleigh anomalies (RAs) in metal nanogratings exhibit an impressive bulk refractive-index sensitivity determined solely by the grating period. However, the surface ...sensitivity (which is a key figure of merit for label-free chemical and biological sensing) needs to be carefully investigated to assess the actual applicability of this technological platform. In this paper, we explore the sensitivity of RAs in metal nanogratings when local refractive-index changes are considered. Our studies reveal that the surface sensitivity deteriorates up to two orders of magnitude by comparison with the corresponding bulk value; interestingly, this residual sensitivity is not attributable to the wavelength shift of the RAs, which are completely insensitive to local refractive-index changes, but rather to a strictly connected plasmonic effect. Our analysis for increasing overlay thickness reveals an ultimate surface sensitivity that approaches the RA bulk value, which turns out to be the upper-limit of grating-assisted surface-plasmon-polariton sensitivities.
Integrating multi-responsive polymers such as microgels onto optical fiber tips, in a controlled fashion, enables unprecedented functionalities to Lab-on-fiber optrodes. The creation of a uniform ...microgel monolayer with a specific coverage factor is crucial for enhancing the probes responsivity to a pre-defined target parameter. Here we report a reliable fabrication strategy, based on the dip coating technique, for the controlled realization of microgel monolayer onto unconventional substrates, such as the optical fiber tip. The latter was previously covered by a plasmonic nanostructure to make it sensitive to superficial environment changes. Microgels have been prepared using specific Poly(
-isopropylacrylamide)-based monomers that enable bulky size changes in response to both temperature and pH variations. The formation of the microgel monolayer is efficiently controlled through the selection of suitable operating pH, temperature and concentration of particle dispersions used during the dipping procedure. The effect of each parameter has been evaluated, and the validity of our procedure is confirmed by means of both morphological and optical characterizations. We demonstrate that when the coverage factor exceeds 90%, the probe responsivity to microgels swelling/collapsing is significantly improved. Our study opens new paradigms for the development of engineered microgels assisted Lab-on-Fiber probes for biochemical applications.
Optical controlling and reading-out highly localized intracellular signaling events in network of neurons, single neurons and subcellular compartments is considered as the most groundbreaking ...innovation in the neuroscience field in recent years. New optical readout and manipulation tools for optogenetics are continuously required. Here we report on a tapered multicore optical fiber system able to achieve multipoint illumination and polychromatic lightening of a target with the resolution of single-cell and single organelles. The steering of the output beam can be achieved by controlling the wavelength and phase of the optical signals coupled to the fiber. Consequently, the change of the direction of the beam can be achieved without rotating the device, reducing the invasiveness of the final device. The possibility to steer the output optical beam can also allow to minimize the photoelectrical and photochemical effects caused by coupling the microelectrode and optical manipulation optoelectronics probes. Finally, our system can also collect light by exploiting multisite photometry approach.
The combination of responsive microgels and Lab-on-Fiber devices represents a valuable technological tool for developing advanced optrodes, especially useful for biomedical applications. Recently, we ...have reported on a fabrication method, based on the dip coating technique, for creating a microgels monolayer in a controlled fashion onto the fiber tip. In the wake of these results, with a view towards industrial applications, here we carefully analyze, by means of both morphological and optical characterizations, the effect of each fabrication step (fiber dipping, rinsing, and drying) on the microgels film properties. Interestingly, we demonstrate that it is possible to significantly reduce the duration (from 960 min to 31 min) and the complexity of the fabrication procedure, without compromising the quality of the microgels film at all. Repeatability studies are carried out to confirm the validity of the optimized deposition procedure. Moreover, the new procedure is successfully applied to different kinds of substrates (patterned gold and bare optical fiber glass), demonstrating the generality of our findings. Overall, the results presented in this work offer the possibility to improve of a factor ~30 the fabrication throughput of microgels-assisted optical fiber probes, thus enabling their possible exploitation in industrial applications.
Antisnake activity of extracts and essential oil of Nectandra megapotamica was tested in vitro against the Bothrops diporus venom (yarará chica). Inhibitory activity of the hemolytic action on the ...aqueous extract and essential oil; inhibition of the procoagulant action on hexanic extract and condensed water from steam distillation; and inhibition of the proteolytic activity on alcoholic extract and condensed water was found. In all cases, the main antisnake venom activity was found on plant material collected in the autumn. The chemical composition of the N. megapotamica essential oil was characterized during different vegetative states finding a clear predominance of mono- (21.0-31.7) and sesquiterpene (58.5-68.9) hydrocarbons. The differences found with previous results published for this species, growing in other geographic places, opens the option for the existence of chemical types.
Despite technological progress in instrumental diagnostic investigations of the last decade, prostate cancer remains one of the most frequent malignant tumors and the second leading cause of cancer ...death among men. Although prostate biopsy remains the reference among all diagnosis procedures, it still exposes patients to the risk of developing complications. In this paper, the authors present a novel robotic system for prostate cancer diagnosis aimed at improving the current diagnostic procedures and reducing their undesired effects. The purpose of this work is to validate the proposed methodology by considering experimental analysis on both phantom and ex-vivo prostate tissues.
PDF
