Mass testing is fundamental to face the pandemic caused by the coronavirus SARS-CoV-2 discovered at the end of 2019. To this aim, it is necessary to establish reliable, fast, and cheap tools to detect viral particles in biological material so to identify the people capable of spreading the infection. We demonstrate that a colorimetric biosensor based on gold nanoparticle (AuNP) interaction induced by SARS-CoV-2 lends itself as an outstanding tool for detecting viral particles in nasal and throat swabs. The extinction spectrum of a colloidal solution of multiple viral-target gold nanoparticles—AuNPs functionalized with antibodies targeting three surface proteins of SARS-CoV-2 (spike, envelope, and membrane)—is red-shifted in few minutes when mixed with a solution containing the viral particle. The optical density of the mixed solution measured at 560 nm was compared to the threshold cycle ( C t ) of a real-time PCR (gold standard for detecting the presence of viruses) finding that the colorimetric method is able to detect very low viral load with a detection limit approaching that of the real-time PCR. Since the method is sensitive to the infecting viral particle rather than to its RNA, the achievements reported here open a new perspective not only in the context of the current and possible future pandemics, but also in microbiology, as the biosensor proves itself to be a powerful though simple tool for measuring the viral particle concentration.

Protontherapy is hadrontherapy’s fastest-growing modality and a pillar in the battle against cancer. Hadrontherapy’s superiority lies in its inverted depth-dose profile, hence tumour-confined irradiation. Protons, however, lack distinct radiobiological advantages over photons or electrons. Higher LET (Linear Energy Transfer) 12C-ions can overcome cancer radioresistance: DNA lesion complexity increases with LET, resulting in efficient cell killing, i.e. higher Relative Biological Effectiveness (RBE). However, economic and radiobiological issues hamper 12C-ion clinical amenability. Thus, enhancing proton RBE is desirable. To this end, we exploited the p + 11B → 3α reaction to generate high-LET alpha particles with a clinical proton beam. To maximize the reaction rate, we used sodium borocaptate (BSH) with natural boron content. Boron-Neutron Capture Therapy (BNCT) uses 10B-enriched BSH for neutron irradiation-triggered alpha particles. We recorded significantly increased cellular lethality and chromosome aberration complexity. A strategy combining protontherapy’s ballistic precision with the higher RBE promised by BNCT and 12C-ion therapy is thus demonstrated.

Development of plasmonic biosensors combining reliability and ease of use is still a challenge. Gold nanoparticle arrays made by block copolymer micelle nanolithography (BCMN) stand out for their scalability, cost-effectiveness and tunable plasmonic properties, making them ideal substrates for fluorescence enhancement. Here, we describe a plasmon-enhanced fluorescence immunosensor for the specific and ultrasensitive detection of Plasmodium falciparum lactate dehydrogenase (PfLDH)—a malaria marker—in whole blood. Analyte recognition is realized by oriented antibodies immobilized in a close-packed configuration via the photochemical immobilization technique (PIT), with a top bioreceptor of nucleic acid aptamers recognizing a different surface of PfLDH in a sandwich conformation. The combination of BCMN and PIT enabled maximum control over the nanoparticle size and lattice constant as well as the distance of the fluorophore from the sensing surface. The device achieved a limit of detection smaller than 1 pg/mL (<30 fM) with very high specificity without any sample pretreatment. This limit of detection is several orders of magnitude lower than that found in malaria rapid diagnostic tests or even commercial ELISA kits. Thanks to its overall dimensions, ease of use and high-throughput analysis, the device can be used as a substrate in automated multi-well plate readers and improve the efficiency of conventional fluorescence immunoassays.

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...