Percorrer por autor "Serafinelli, Caterina"
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- Arrayed graphene enhanced surface plasmon resonance for sensing applicationsPublication . Fantoni, Alessandro; Vygranenko, Yuri; Maçarico, António; Serafinelli, Caterina; Fernandes, Miguel; Mansour, Rima; Jesus, Rui; Vieira, ManuelaCombination of carbon-based nanomaterials (CNMs) with AuNPs has been demonstrated to enhance the LSPR response and facilitate the functionalization with specific and selective antibodies. Also, the introduction of CNMs in the plasmonic layer allows tuning of the LSPR central frequency. Joining the double dependence of the LSPR on the MNPs size and the presence of CNMs, it is possible to create a set of plasmonic layers whose LSPR wavelengths are distributed in a spectral range of few tenth of nanometers. This consideration paves the way to an LSPR sensor with an arrayed structure, where each element maximizes its specific LSPR at its own wavelength. Illumination with a broad light source produces a different response in each one of the elements. The working process underlying the sensing operation is that each element of the sensor array acts like a band-stop optical filter for a specific wavelength. The output can be extracted by the application of an image analysis approach to the spatially modulated light crossing the sensor area, based on a color recognition algorithm. A change in the refractive index over the sensor array will shift the rejection band of the sensing elements. An automatized method for color recognition can support the analysis of the refractive index variations yielding the final sensor output. A figure of merit, highlighting the LSPR central wavelength and spectral extension for different LSPR configurations, is also obtained for different sizes of the AuNPs and different flavors of CNMs.
- Enhanced plasmonic properties of metal nanoparticles/WS2 hybridsPublication . Serafinelli, Caterina; Fantoni, AlessandroIn this work, the state-of-the-art of devices based on plasmonic metal nanoparticles hybridized with WS2 nanosheets has been reviewed. The physical phenomena behind the light-matter interactions such as carrier generation in photodetector devices or changes in exciton dynamics in photoluminescence (PL) have been discussed, nevertheless the application of devices based on WS2 nanosheets hybridized with plasmonic metal nanoparticles is still in an early stage thus revealing a great potential in a broad range of applications. For example, it is provided a new way to develop a high-performance photodetector stable in harsh environment or improved SPR sensor for clinical diagnosis.
- Gold nanoflowers for colorimetric detection of NGAL antibodiesPublication . Serafinelli, Caterina; Fantoni, Alessandro; Alegria, Elisabete C. B. A.; Pacheco, Rita; Vieira, Manuela; Vieira, Manuela; Pacheco, Rita; Alegria, Elisabete; Fantoni, AlessandroColorimetric sensors are a type of sensing platform enabling visual measurements that offers an instant report. Due to their intrinsic advantages, such as low cost, simplicity, low acquisition time and no need for expensive instrumentation, colorimetric transducers are attracting a growing attention for the PoC devices. In light of their brilliant colors arising from their Localized Surface Plasmon Resonance (LSPR), gold nanoparticles have revealed a great potential to develop new analytical techniques and advanced assays. Stimulated by the need of PoC devices for an affordable and real-time detection of biomarkers outside clinical environment, in this work we explore the potential of gold nanoflowers (AuNFs) as sensing system to integrate in a PoC device. Firstly, gold AuNFs functionalized with NGAL antibodies along with antibodies conjugated onto AuNFs surface binding their complementary antigens will be synthesized and their transmittance spectra measured. In a successive step, the measured spectra have been converted into vectors in the L*a*b*, xyY and RGB Color spaces by means of simulation study. Transferring the study into real world application, the AuNFs will be integrated into the fiber network of paper to create the plasmonic paper that will be the transducer of a colorimetric device.
- Gold nanoparticles functionalized with antibodies: a colorimetric analysis for implementation in PoC devicesPublication . Serafinelli, Caterina; Fantoni, Alessandro; Alegria, Elisabete C.B.A.; Pacheco, Rita; Vieira, Manuela; Fantoni, Alessandro; Alegria, Elisabete; Pacheco, Rita; Vieira, ManuelaThe growing interest in the fast and easy identification of many biomarkers for several diseases, supporting a future precision medicine, results in the development of miniaturized, user-friendly, automated, and portable sensing systems able to provide a real-time and reliable response. Herein we evaluate the sensing capability of gold nanoflowers (AuNFs) for their integration in the setup of the Color Picker System, a Point-of-Care (PoC) sensing device developed by our group for a user-friendly colorimetric detection of molecules. A simulation study measures the color changes arising from the variations in the dielectric environment around the AuNFs surface. The process starts with the synthesis of AuNFs and their functionalization with 3-Mercaptopropionic acid. The measured transmittance spectra of the AuNFs before and after the functionalization, have been combined with the spectra of two different light sources to simulate the spectral response of the light transmitted through the colloidal dispersion. The calculated spectra have been converted into vectors in different color spaces producing the color chart. The sensitivity of the AuNFs has been evaluated as Euclidian distance between two consecutive points in the color chart, but also as differences in the RGB channels, that are the one returned from the Color Picker System. The AuNFs showed the greatest distances in the color chart and the greatest differences in the RGB when using the Cold LED as light source. The chromatic changes arising from their use make the AuNFs a potential sensing platform to be inserted into the Color Picker System for antibodies sensing. © 2025 SPIE.
- Recent progresses in plasmonic biosensors for Point-of-Care (POC) devices: A critical reviewPublication . Serafinelli, Caterina; Fantoni, Alessandro; Alegria, Elisabete; Vieira, ManuelaThe recent progresses in the research of plasmonic phenomena and materials paved the route toward the development of optical sensing platforms based on metal nanostructures with a great potential to be integrated into point-of-care (POC) devices for the next generation of sensing platforms, thus enabling real-time, highly sensitive and accurate diagnostics. In this review, firstly, the optical properties of plasmonic metal nanoparticles will be illustrated, whereafter the engineering of POC platforms, such as microfluidics and readout systems, will be considered with another critical point which is surface functionalization. Attention will also be given to their potential in multiplexed analysis. Finally, the limitations for effective implementation in real diagnostics will be illustrated with a special emphasis on the latest trend in developing cutting-edge sensing systems.