Recent advances on the development of plasmon-assisted biosensors for detection of C-reactive protein.

Human C-reactive protein (CRP), an early clinical indicator of infectious or inflammatory conditions has been recently identified as a key biomarker associated with the development of COVID-19. The rapid and accurate determination of CRP level in blood serum is an urgent need to predict timely the risk of disease worsening. The emergence of nanotechnological tools has provided an attractive perspective in designing portable bioanalytical assays with fast response time, high sensitivity and specificity, and multiplexing capability for accurate, on-site disease diagnosis and monitoring. Due to their versatile optical properties, plasmonic nanoparticles (PNPs) are appealing candidates for biosensing applications. This review summarizes the advances in the application of PNPs for CRP detection and quantification. Particularly, we review the improvements attained in the detection of CRP using aggregation-based colorimetric, localized surface plasmon resonance (LSPR), plasmon-assisted fluorescence and chemiluminescence, and surface-enhanced Raman scattering (SERS) spectroscopic methods.

Fabrication of gold-silver core-shell nanoparticles for performing as ultrabright SERS-nanotags inside human ovarian cancer cells.

This paper presents the fabrication and characterization of new gold-silver core-shell nanoparticles labeled with para-mercaptobenzoic acid (4MBA) molecules and demonstrates their use as surface-enhanced Raman spectroscopy (SERS)-nanotags with ultra-bright traceability inside cells and ability to convey spectrally-coded information about the intracellular pH by means of SERS. Unlike previous reported studies, our fabrication procedure includes in the first step the synthesis of chitosan-coated gold nanoparticles as a seed material with subsequent growing of a silver shell. The bimetallic core-shell structure is revealed by transmission electron microscopy, high-angle annular dark field scanning transmission electron microscopy, energy-dispersive x-ray elemental mapping and the presence of two interacting localized surface plasmon resonance modes in UV-vis extinction spectrum. The high SERS activity and sensitivity of as fabricated 4MBA-chit-Au-AgNPs nano-constructs to different pH in solution is investigated under 532 and 633 nm laser lines excitation. Next, in view of future studies in cancer diagnosis, the in vitro antiproliferative effects of SERS-nanotags against human ovarian adenocarcinoma cells (NIH:OVCAR-3) are evaluated. The capacity to operate as bright SERS nanotags with precise localization at a single cell level as well as intracellular pH indicators is clearly demonstrated by performing cell imaging under scanning confocal Raman microscopy.

SChitosan-capped gold nanoparticles impair radioresistant glioblastoma stem-like cells.

PURPOSE: Glioblastoma is a rapidly evolving lethal disease mainly due to its highly chemo- and radioresistant glioblastoma stem cells (GSCs). Herein, we tested if chitosan-capped gold nanoparticles (Chit-GNPs) may overcome the limitations of drug concentrations by increased cell internalization in GSCs and if such GNPs could enhance the response to irradiation. METHODS: Chitosan was used for Chit-GNP synthesis as a reducing and stabilizing agent. Chit-GNPs were characterized by spectroscopy, dark field, transmission electron microscopy and zeta potential measurements. Patient-derived GSCs and human osteoblasts were treated with increasing concentrations of nanoparticles and irradiated. The uptake and cytotoxicity of Chit-GNPs were compared to that of uncoated GNPs. RESULTS: The positively-charged, 26 nm-sized, spherical Chit-GNPs, showed a huge intracellular accumulation into the cytosol, lysosomes and near the nucleus, whereas no uncoated GNPs were internalized within GSCs. Surprisingly, Chit-GNPs were highly cytotoxic for GSCs irrespective of cell irradiation, that failed to add an additional benefit when combined with Chit-GNPs/GNPs. Moreover, Chit-GNPs were selectively cytotoxic for GSCs and did not affect the normal cells, despite an increased nanoparticle internalization. CONCLUSIONS: The important Chit-GNP internalization and their selective cytotoxicity for GSCs make this compound a potential novel anticancer agent and a promising backbone for drug delivery in glioblastoma.

Optimization of Tyrosine Kinase Inhibitor-Loaded Gold Nanoparticles for Stimuli-Triggered Antileukemic Drug Release.

Tyrosine kinase inhibitor (TKI) therapy is gaining attraction in advanced cancer therapeutics due to the ubiquity of kinases in cell survival and differentiation. Great progress was made in the past years in identifying tyrosine kinases that can function as valuable molecular targets and for the entrapment of their corresponding inhibitors in delivery compounds for triggered release. Herein we present a class of drug-delivery nanocompounds based on TKI Midostaurin-loaded gold nanoparticles that have the potential to be used as theranostic agents for the targeting of the FMS-like tyrosine kinase 3 (FLT3) in acute myeloid leukemia. We optimized the nanocompounds' formulation with loading efficiency in the 84-94% range and studied the drug release behavior in the presence of stimuli-responsive polymers. The therapeutic activity of MDS-loaded particles, superior to that of the free drug, was confirmed with toxicities depending on specific dosage ranges. No effect was observed on FLT3-negative cells or for the unloaded particles. Beyond druggability, we can track this type of nanocarrier inside biological structures as demonstrated via dark field microscopy. These properties might contribute to the facilitation of personalized drug dosage administration, critical for attaining a maximal therapeutic effect.

Folate-targeted Pluronic-chitosan nanocapsules loaded with IR780 for near-infrared fluorescence imaging and photothermal-photodynamic therapy of ovarian cancer.

Herein, we report the fabrication of a nanotherapeutic platform integrating near-infrared (NIR) imaging with combined therapeutic potential through photodynamic (PDT) and photothermal therapies (PTT) and recognition functionality against ovarian cancer. Owing to its NIR fluorescence, singlet oxygen generation and heating capacity, IR780 iodide is exploited to construct a multifunctional nanosystem for single-wavelength NIR laser imaging-assisted dual-modal phototherapy. We opted for loading IR780 into polymeric Pluronic-F127-chitosan nanoformulation in order to overcome its hydrophobicity and toxicity and to allow functionalization with folic acid. The obtained nanocapsules show temperature-dependent swelling and spectroscopic behavior with favorable size distribution for cellular uptake at physiological temperatures, improved fluorescence properties and good stability. The fabricated nanocapsules can efficiently generate singlet oxygen in solution and are able to produce considerable temperature increase (46 °C) upon NIR laser irradiation. Viability assays on NIH-OVCAR-3 cells confirm the successful biocompatibilization of IR780 by encapsulating in Pluronic and chitosan polymers. NIR fluorescence imaging assays reveal the ability of folic-acid functionalized nanocapsules to serve as intracellular contrast agents and demonstrate their active targeting capacity against folate receptor expressing ovarian cancer cells (NIH-OVCAR-3). Consequently, the targeted nanocapsules show improved NIR laser induced phototherapeutic performance against NIH-OVCAR-3 cells compared to free IR780. We anticipate that this class of nanocapsules holds great promise as theranostic agents for application in image-guided dual PDT-PTT and imaging assisted surgery of ovarian cancer.

Carboplatin-Loaded, Raman-Encoded, Chitosan-Coated Silver Nanotriangles as Multimodal Traceable Nanotherapeutic Delivery Systems and pH Reporters inside Human Ovarian Cancer Cells.

Ovarian cancer is a common cause of cancer death in women and is associated with the highest mortality rates of all gynecological malignancies. Carboplatin (CBP) is the most used cytotoxic agent in the treatment of ovarian cancer. Herein, we design and assess a CBP nanotherapeutic delivery system which allows combinatorial functionalities of chemotherapy, pH sensing, and multimodal traceable properties inside live NIH:OVCAR-3 ovarian cancer cells. In our design, a pH-sensitive Raman reporter, 4-mercaptobenzoic acid (4MBA) is anchored onto the surface of chitosan-coated silver nanotriangles (chit-AgNTs) to generate a robust surface-enhanced Raman scattering (SERS) traceable system. To endow this nanoplatform with chemotherapeutic abilities, CBP is then loaded to 4MBA-labeled chit-AgNTs (4MBA-chit-AgNTs) core under alkaline conditions. The uptake and tracking potential of CBP-4MBA-chit-AgNTs at different Z-depths inside live ovarian cancer cells is evaluated by dark-field and differential interference contrast (DIC) microscopy. The ability of CBP-4MBA-chit-AgNTs to operate as near-infrared (NIR)-responsive contrast agents is validated using two noninvasive techniques: two-photon (TP)-excited fluorescence lifetime imaging microscopy (FLIM) and confocal Raman microscopy (CRM). The most informative data about the precise localization of nanocarriers inside cells correlated with intracellular pH sensing is provided by multivariate analysis of Raman spectra collected by scanning CRM. The in vitro cell proliferation assay clearly shows the effectiveness of the prepared nanocarriers in inhibiting the growth of NIH:OVCAR-3 cancer cells. We anticipate that this class of nanocarriers holds great promise for application in image-guided ovarian cancer chemotherapy.

Antibody Conjugated, Raman Tagged Hollow Gold-Silver Nanospheres for Specific Targeting and Multimodal Dark-Field/SERS/Two Photon-FLIM Imaging of CD19(+) B Lymphoblasts.

In this Research Article, we propose a new class of contrast agents for the detection and multimodal imaging of CD19(+) cancer lymphoblasts. The agents are based on NIR responsive hollow gold-silver nanospheres conjugated with antiCD19 monoclonal antibodies and marked with Nile Blue (NB) SERS active molecules (HNS-NB-PEG-antiCD19). Proof of concept experiments on specificity of the complex for the investigated cells was achieved by transmission electron microscopy (TEM). The microspectroscopic investigations via dark field (DF), surface-enhanced Raman spectroscopy (SERS), and two-photon excited fluorescence lifetime imaging microscopy (TPE-FLIM) corroborate with TEM and demonstrate successful and preferential internalization of the antibody-nanocomplex. The combination of the microspectroscopic techniques enables contrast and sensitivity that competes with more invasive and time demanding cell imaging modalities, while depth sectioning images provide real time localization of the nanoparticles in the whole cytoplasm at the entire depth of the cells. Our findings prove that HNS-NB-PEG-antiCD19 represent a promising type of new contrast agents with great possibility of being detected by multiple, non invasive, rapid and accessible microspectroscopic techniques and real applicability for specific targeting of CD19(+) cancer cells. Such versatile nanocomplexes combine in one single platform the detection and imaging of cancer lymphoblasts by DF, SERS, and TPE-FLIM microspectroscopy.

Nanomedicine approaches in acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is the malignancy with the highest incidence amongst children (26% of all cancer cases), being surpassed only by the cancers of the brain and of the nervous system. The most recent research on ALL is focusing on new molecular therapies, like targeting specific biological structures in key points in the cell cycle, or using selective inhibitors for transmembranary proteins involved in cell signalling, and even aiming cell surface receptors with specifically designed antibodies for active targeting. Nanomedicine approaches, especially by the use of nanoparticle-based compounds for the delivery of drugs, cancer diagnosis or therapeutics may represent new and modern ways in the near future anti-cancer therapies. This review offers an overview on the recent role of nanomedicine in the detection and treatment of acute lymphoblastic leukemia as resulting from a thorough literature survey. A short introduction on the basics of ALL is presented followed by the description of the conventional methods used in the ALL detection and treatment. We follow our discussion by introducing some of the general nano-strategies used for cancer detection and treatment. The detailed role of organic and inorganic nanoparticles in ALL applications is further presented, with a special focus on gold nanoparticle-based nanocarriers of antileukemic drugs.