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Advances in Nanotheranostics with Plasmonic and Magnetic Nanoparticles
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
Sérgio R. S. Veloso, Paula M. T. Ferreira, J. A. Martins, Paulo J. G. Coutinho, Elisabete M. S. Castanheira
Moreover, the SPR is dependent on both particle size and environment (particularly on the dielectric constant), which can be explored in the development of sensors where the bonding of molecules or their proximity to the nanoparticle surface will modify the SPR frequency [37]. Apart from the environment, the plasmon band is sensible to the type of ligand (donor or withdrawing ligand), core charge, temperature, shape and aggregation, the latter inducing effects such as bathochromic shift and bandwidth widening owing to the interparticle plasmonic coupling [37]. The nanoparticles can also induce fluorescence quenching due to Förster resonance energy transfer or modulated photoinduced electron transfer [37]. Hereby, plasmonic nanoparticles, mainly the gold-based ones, have found application in different technological areas such as biosensors, clinic chemistry methods, immunologic assays, photothermolysis of tumour cells, detection and control of microorganisms, transport of drugs and monitorisation of biological cells [35, 39–41].
Combined ultrasound and photoacoustic imaging
Published in Yi-Hwa Liu, Albert J. Sinusas, Hybrid Imaging in Cardiovascular Medicine, 2017
Doug Yeager, Andrei Karpiouk, Nicholas Dana, Stanislav Emelianov
Noble metal nanoparticles represent a widely investigated category of PA contrast agents. Metallic nanoparticles are of particular interest to researchers because they exhibit surface plasmon resonance (SPR) coupling, a process in which free electrons at the nanoparticle surface oscillate with the applied electromagnetic field, which enables very high, tunable optical absorption properties based on modifications to the nanoparticles size and shape (Grzelczak et al. 2008; Xia et al. 2009). As a result of the SPR effect, an individual nanoparticle exhibits very high optical absorption, up to five orders of magnitude greater than that exhibited by a dye molecule (Jain et al. 2006), resulting in efficient PA signal generation. Additionally, the size and shape of these plasmonic nanoparticles can be easily tailored, resulting in changes to their optical absorption spectrum and the ability to use sPA imaging for their detection over background endogenous tissues. For example, the location of the peak absorbance generated by rod-shaped gold nanoparticles can be adjusted within the NIR optical window by tuning the particles’ aspect ratios (Nikoobakht and El-Sayed 2003). In fact, a significant number of gold nanoparticle PA contrast agents have been developed, including spherical gold nanoparticles (Mallidi et al. 2009; Wang et al. 2009), gold nanoshells (Liangzhong et al. 2006; Yang et al. 2007), gold nanorods (Bayer et al. 2011; Chen et al. 2011; Meng-Lin et al. 2008; Song et al. 2009; Yeager et al. 2012), gold nanoplates (Millstone et al. 2009), gold nanocages (Skrabalak et al. 2008), and aggregated gold nanoclusters (Yoon et al. 2010). Each of these gold particles has its own unique physical and optical absorption properties. Silver nanoparticles have also been developed and investigated for PA imaging applications (Homan et al. 2010). Similar to the other classes of PA contrast agents, the surface of plasmonic nanoparticles can be readily conjugated with targeting moieties for molecular imaging applications (Kumar, Aaron, and Sokolov 2008) or otherwise modified to improve their stability (Chen et al. 2010) and PA signal generation efficiency (Chen et al. 2011). As a result, plasmonic nanoparticle delivery followed by sPA imaging can be employed to greatly expand cellular and molecular imaging capabilities from that achieved based solely on endogenous absorbers.
Advances in plasmonic-based MOF composites, their bio-applications, and perspectives in this field
Published in Expert Opinion on Drug Delivery, 2022
Sorraya N. K. Lelouche, Catalina Biglione, Patricia Horcajada
Photo-active nanomaterials have been extensively investigated for applications in biology [1]. Several factors can explain their interest. One of the main reasons being that nanosized materials are favorable to the process of endocytosis, acting as nanocarriers or diagnostic tools, among others [2]. Particularly, plasmonic nanoparticles (NPs) have been the focus of interest due to the property which give its name to this group of material (plasmon). When the NPs are irradiated (with a wavelength superior to the diameter of the particle), the conductive electrons oscillate coherently; which results in the phenomenon defined as Localized Surface Plasmon Resonance (LSPR), being dependent on its size, shape, and composition. Typically, these particles are chemically based on gold, silver, palladium, and platinum. Plasmonic NPs have been reported to have molar absorption extinction coefficient of up to 1011 M−1·cm−1, as well as high scattering cross section, making them more efficient than fluorescent molecules. Furthermore, unlike the latter, plasmonic NPs do not photo-bleach [3]. These properties lead to their use in the field of biomedicine, mainly for bioimaging and immunoassays.
Fourier-transform Infrared (FT-IR) spectroscopy fingerprints subpopulations of extracellular vesicles of different sizes and cellular origin
Published in Journal of Extracellular Vesicles, 2020
Lucia Paolini, Stefania Federici, Giovanni Consoli, Diletta Arceri, Annalisa Radeghieri, Ivano Alessandri, Paolo Bergese
Complementary spectroscopic approaches, such as Raman spectroscopy, have already been reported to distinguish EVs [12–14]. However, Raman Spectroscopy suffers from very low sensitivity. This drawback is often circumvented by coupling the analytes with plasmonic nanoparticles (SERS) [15,16], by labelling them with organic dyes (Raman reporters), or immune-labelling with nanoprobes [17]. These strategies allowed to distinguish EVs from various sources, disease contexts [18,19] and single-vesicle analysis [20–22]. SERS-active nanostructures can enhance the Raman signals of target molecules by several orders of magnitude, but can have problems in stability, poor reproducibility, and sample damaging according to their material composition and architecture [23,24]. Those approaches might introduce pitfalls in data analysis, which might strongly affect the classification of EV subpopulations. Moreover, commercially available instrumentation for Raman spectroscopy is typically more complex and expensive than the corresponding FT-IR spectrometers. For these reasons, we decided to focus our study on FT-IR.
Localized surface plasmon resonance based biosensing
Published in Expert Review of Molecular Diagnostics, 2018
Andrea Csáki, Ondrej Stranik, Wolfgang Fritzsche
Enhancement of the LSPR sensing is also possible in the (bio)assay design. Different concepts have been proposed besides one-step affinity binding in order to realize a better sensing efficiency: the use of competitive assays, dendromeric enhancement concepts, enzymatic enhancement, or target recycling [165]. By increasing the mass and by decreasing the binding radius of the analyte, a higher sensor response is expected [166]. The sensor response can be increased when measuring occurs in dried state [115,167]. The use of additionally plasmonic nanoparticles as label results in a significantly higher signal response. Chromophores as labels induce also a spectral shift enhancement, particularly in the case of resonance overlap of the plasmon peak with the absorption spectra of the chromophores [168–170]. Conformational switches, e.g. by reduction reactions, allow a better differentiation of resonant and non-resonant states (molecular plasmonic switching) [171]. By adjusting of the interaction, e.g. by nanoparticle heterodimers, the interparticle distance can be modulated using conformational changes of the bridging molecules actively [172].