Nanostructured Surfaces as Plasmonic Biosensors: A Review

Abstract

are the main features exhibited by metal nanostructures thereby opening up the possibility for manipulating light at nanometric scale, well below the diffraction limit. [1] So far, the tremendous potentialities of the plasmon-related effects have been already represented a breakthrough in many application fields such as cancer treatment, [2] ultrasensitive molecule detection, [3] integrated circuitry, [4] quantum optics, [5] optoelectronics, [6] photovoltaics. [7] Several types of plasmonic nanostructures are being conceived these days aiming at improving the performance of plasmon-based devices. [8,9] At the basis of the nonpropagating plasmon phenomena there is the localized surface plasmon resonance (LSPR), namely, the collective oscillation of the conduction electron cloud against the metal core. [10] The plasmonic properties of metal nanomaterials strongly depend on the nanostructure geometry, arrangement, and environment. For instance, exotic nanostructures such as nanocages, nanoscaffolds, and bow-tie nanoantennas exhibit higher field enhancement than conventional nanoparticles with smooth surfaces thereby representing a considerable advantage in applications relying on signal amplification such as surface-enhanced Raman spectroscopy (SERS), [11,12] surface-enhanced infrared absorption (SEIRA), [13,14] and plasmon-enhanced fluorescence (PEF). [15,16] In addition, when nanostructures are ordered in periodic arrays, new modes can arise as a result of the near-or far-field coupling among the localized plasmons so as to activate hybrid effects such as coupled LSPR (c-LSPR) [17,18] and surface lattice resonance (SLR), [19][20][21] respectively. Besides, plasmonic properties offered by metamaterials were recently investigated and sparked considerable interest since they demonstrated to offer significantly better performance as compared to metal-based nanostructures in many fields of applications such as biosensing, [22] photonics, [23] photovoltaics, [24] and optoelectronics. [25] Nevertheless, the actual implications are still far-reaching for many scientific and engineering fields due to their complexity and low awareness. [25] Therefore, the possibility to tune the optical response of a nanostructure by tailoring the material, shape, and size, as well as the pattern architecture, is spurring the researchers to explore new approaches, in terms of both nanofabrication and nanoapplications, in order to go beyond the current limits of many techniques.The aim of the present work is to provide a comprehension of this growing field of research and to convey the main features of the nanostructured surfaces to biosensing applications.Conventional laboratory techniques exhibit impressive sensing performance and still constitute an irreplaceable tool in bioanalytics. Nevertheless, high costs, time consumption, and need for well-equipped laboratories and skilled personnel make highly desirable to explore novel strategies to carry out biochemical analyses. In this regard, biosensor-based methods represent a promising appr...

Emerging early diagnostic methods for acute kidney injury

“…SPR method has the advantages of real-time, fast, and high sensitivity for NGAL detection compared with the traditional ELSA method 130 - 132 . Recently, Gupta et al developed reusable SPR biosensor based on the NGAL antibody 133 ( Figure 10 A ).…”

Plasmonic Nanosensors: Design, Fabrication, and Applications in Biomedicine

“…Vice versa, plasmonic NPs with broad resonances (with large FWHM) represent the ideal plasmonic nanoantennas for external signal amplification (SERS and MEF-based sensing mechanisms). Despite all the reported fabrication strategies and ultra-high performances achieved by the proposed devices, it seems that the technology transfer remains the main bottleneck of the establishment of plasmonics as a gold standard in the biosensing community [193]. Therefore, the real application of the described devices will be possible only when the proposed technologies will be made intuitive, largely understandable, and reliable, also by non-specialized personnel.…”

H3 (Hydrogel‐Based, High‐Sensitivity, Hybrid) Plasmonic Transducers for Biomolecular Interactions Monitoring

“…[3,4] Polymers ensure high flexibility, adaptability to nonplanar surfaces, and ease of integration within (PEF), exploit the LSPR to increase the signal intensity of fluorescent dyes, depending on the spectral overlapping between plasmonic absorption and fluorescent dye extinction/emission and their separation distance. [27][28][29][30] Moreover, the combination of plasmonic nanoparticles with polymers has been enabling novel functionalities and transduction mechanisms based on the different mechanical properties of flexible substrates. [5,[31][32][33] In particular, the synergy between plasmonic nanoparticles and hydrogels has been already shown to be a promising approach for the design of biochemical sensors.…”