Publications by authors named "Sonia Centi"

29 Publications

  • Page 1 of 1

Enhanced Antitumoral Activity and Photoacoustic Imaging Properties of AuNP-Enriched Endothelial Colony Forming Cells on Melanoma.

Adv Sci (Weinh) 2021 Feb 21;8(4):2001175. Epub 2020 Dec 21.

Department of Experimental and Clinical Biomedical Sciences University of Florence Florence 50134 Italy.

Near infrared (NIR)-resonant gold nanoparticles (AuNPs) hold great promise in cancer diagnostics and treatment. However, translating the theranostic potential of AuNPs into clinical applications still remains a challenge due to the difficulty to improve the efficiency and specificity of tumor delivery in vivo as well as the clearance from liver and spleen to avoid off target toxicity. In this study, endothelial colony forming cells (ECFCs) are exploited as vehicles to deliver AuNPs to tumors. It is first demonstrated that ECFCs display a great capability to intake AuNPs without losing viability, and exert antitumor activity per se. Using a human melanoma xenograft mouse model, it is next demonstrated that AuNP-loaded ECFCs retain their capacity to migrate to tumor sites in vivo 1 day after injection and stay in the tumor mass for more than 1 week. In addition, it is demonstrated that ECFC-loaded AuNPs are efficiently cleared by the liver over time and do not elicit any sign of damage to healthy tissue.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/advs.202001175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887578PMC
February 2021

Photostability of Contrast Agents for Photoacoustics: The Case of Gold Nanorods.

Nanomaterials (Basel) 2021 Jan 6;11(1). Epub 2021 Jan 6.

Istituto di Fisica Applicata Nello Carrara, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy.

Plasmonic particles as gold nanorods have emerged as powerful contrast agents for critical applications as the photoacoustic imaging and photothermal ablation of cancer. However, their unique efficiency of photothermal conversion may turn into a practical disadvantage, and expose them to the risk of overheating and irreversible photodamage. Here, we outline the main ideas behind the technology of photoacoustic imaging and the use of relevant contrast agents, with a main focus on gold nanorods. We delve into the processes of premelting and reshaping of gold nanorods under illumination with optical pulses of a typical duration in the order of few ns, and we present different approaches to mitigate this issue. We undertake a retrospective classification of such approaches according to their underlying, often implicit, principles as: constraining the initial shape; or speeding up their thermal coupling to the environment by lowering their interfacial thermal resistance; or redistributing the input energy among more particles. We discuss advantages, disadvantages and contexts of practical interest where one solution may be more appropriate than the other.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/nano11010116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825532PMC
January 2021

A bionic shuttle carrying multi-modular particles and holding tumor-tropic features.

Mater Sci Eng C Mater Biol Appl 2020 Dec 7;117:111338. Epub 2020 Aug 7.

Istituto di Fisica Applicata "Nello Carrara", Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino, FI, Italy.

The systemic delivery of composite nanoparticles remains an outstanding challenge in cancer nanomedicine, and the principal reason is a complex interplay of biological barriers. In this regard, adaptive cell transfer may represent an alternative solution to circumvent these barriers down to the tumor microenvironment. Here, tumor-tropic macrophages are proposed as a tool to draw and vehiculate modular nanoparticles integrating magnetic and plasmonic components. The end result is a bionic shuttle that exhibits a plasmonic band within the so-called therapeutic window arising from as much as 40 pg Au per cell, magnetization in the order of 150 pemu per cell, and more than 90% of the pristine viability and chemotactic activity of its biological component, until at least two days of preparation. Its synergistic combination of plasmonic, magnetic and tumor-tropic functions is assessed in vitro for applications as magnetic guidance or sorting, with a propulsion around 4 μm s for a magnetic gradient of 0.8 T m, the optical hyperthermia of cancer, with stability of photothermal conversion to temperatures exceeding 50C, and the photoacoustic imaging of cancer under realistic conditions. These results collectively suggest that a bionic design may be a promising roadmap to reconcile the efforts for multifunctionality and targeted delivery, which are both key goals in nanomedicine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2020.111338DOI Listing
December 2020

Optically activated and interrogated plasmonic hydrogels for applications in wound healing.

J Biophotonics 2020 09 25;13(9):e202000135. Epub 2020 Jun 25.

Istituto di Fisica Applicata "Nello Carrara", Consiglio Nazionale delle Ricerche, Sesto Fiorentino, Florence, Italy.

We disclose the use of hybrid materials featuring Au/Ag core/shell nanorods in porous chitosan/polyvinyl alcohol scaffolds for applications in tissue engineering and wound healing. The combination of Au and Ag in a single construct provides synergistic opportunities for optical activation of functions as near infrared laser tissue bonding, and remote interrogation to return parameters of prognostic relevance in wound healing monitoring. In particular, the bimetallic component ensures optical tunability, enhanced shelf life and photothermal stability, serves as a reservoir of germicidal silver cations, and changes in near-infrared and visible color according to the environmental level of oxidative stress. At the same time, the polymeric blend is ideal to bind connective tissue upon photothermal activation, and to support fabrication processes that provide high porosity, such as electrospinning, thus putting all the premises for cellular repopulation and antimicrobial protection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.202000135DOI Listing
September 2020

Impact of Kapitza resistance on the stability and efficiency of photoacoustic conversion from gold nanorods.

J Colloid Interface Sci 2020 Oct 6;578:358-365. Epub 2020 Jun 6.

Istituto di Fisica Applicata Nello Carrara, IFAC-CNR, Via Madonna del Piano 10, Sesto Fiorentino 50019, Italy.

Plasmonic particles have been proposed for a broad variety of optical and hybrid applications, including the photothermal ablation and photoacoustic imaging of cancer, or their integration in photonic sensors. Here, we address the effect of thermal resistance at the gold-water interface, or Kapitza resistance, on the performance of photoacoustic conversion of gold nanorods. Our findings point to possible strategies for the optimization of plasmonic particles as contrast agents for imaging, or even as transducers for biosensing. We perform numerical simulations that project a simultaneous increase of efficiency and stability of photoacoustic conversion with a decrease of Kapitza resistance. We suggest an effective approach to modulate Kapitza resistance by including underresolved features as roughness or the presence of adsorbates. Inspired by this idea, we synthesize a rough variant of gold nanorods by the deposition and galvanic replacement of a silver shell, where roughness provides higher photoacoustic signals by about 70% and damage thresholds by 120%. In addition, we coat our particles with a protein corona and find a decrease of photoacoustic signals with shell thickness, which may inspire new solutions for biosensors based on a mechanism of photoacoustic transduction. Both our findings are consistent with an effective modulation of Kapitza resistance, which decreases upon roughening, due to an underlying increase of specific surface area, and increases upon coating with a protein shell that may act as a thermal insulation. We discuss possible directions to gain more advantage of our concept for topical applications at the crossroads of plasmonics, biomedical optics and biosensing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2020.05.108DOI Listing
October 2020

Microbubble Resonators for All-Optical Photoacoustics of Flowing Contrast Agents.

Sensors (Basel) 2020 Mar 18;20(6). Epub 2020 Mar 18.

CNR-IFAC, Istituto di Fisica Applicata "Nello Carrara", Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I50019 Sesto Fiorentino (FI), Italy.

In this paper, we implement a Whispering Gallery mode microbubble resonator (MBR) as an optical transducer to detect the photoacoustic (PA) signal generated by plasmonic nanoparticles. We simulate a flow cytometry experiment by letting the nanoparticles run through the MBR during measurements and we estimate PA intensity by a Fourier analysis of the read-out signal. This method exploits the peaks associated with the MBR mechanical eigenmodes, allowing the PA response of the nanoparticles to be decoupled from the noise associated with the particle flow whilst also increasing the signal-to-noise ratio. The photostability curve of a known contrast agent is correctly reconstructed, validating the proposed analysis and proving quantitative PA detection. The experiment was run to demonstrate the feasible implementation of the MBR system in a flow cytometry application (e.g., the detection of venous thrombi or circulating tumor cells), particularly regarding wearable appliances. Indeed, these devices could also benefit from other MBR features, such as the extreme compactness, the direct implementation in a microfluidic circuit, and the absence of impedance-matching material.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s20061696DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175143PMC
March 2020

Fiber-cap biosensors for SERS analysis of liquid samples.

J Mater Chem B 2020 02;8(8):1629-1639

European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy. and National Institute of Optics, National Research Council (INO-CNR), Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy and Department of Physics, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, Italy.

Optical detection techniques based on surface enhanced Raman spectroscopy (SERS) are a powerful tool for biosensing applications. Meanwhile, due to technological advances, different approaches have been investigated to integrate SERS substrates on the tip of optical fibres for molecular probing in liquids. To further demonstrate the perspectives offered by SERS-on-fiber technology for diagnostic purposes, in this study, novel cap-shaped SERS sensors for reversible coupling with customized multimodal probes were prototyped via low-cost polymer casting of polydimethylsiloxane (PDMS) and further assembly of gold nanoparticles (Au NPs) of varied sizes and shapes. To demonstrate the feasibility of liquid sensing with cap sensors using backside illumination and detection, the spectra of rhodamine were acquired by coupling the caps with the fiber. As expected by UV-vis, the highest SERS efficiency was observed for NP-decorated substrates with plasmonic properties in resonance with the irradiation wavelength. Then, SERS biosensors for the specific detection of amyloid-β (Aβ) neurotoxic biomarkers were realized by covalent grafting of Aβ antibodies. As attested by fluorescence images and SERS measurements, the biosensors successfully exhibited enhanced Aβ affinity compared to the bare sensors without ligands. Finally, these versatile (bio)sensors are a powerful tool to transform any milli-sized fibers into functional (bio)sensing platforms with plasmonic and biochemical properties tailored for specific applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9tb01866bDOI Listing
February 2020

Hybrid organosilicon/polyol phantom for photoacoustic imaging.

Biomed Opt Express 2019 Aug 2;10(8):3719-3730. Epub 2019 Jul 2.

Istituto di Fisica Applicata 'Nello Carrara' IFAC-CNR, Via Madonna del Piano, 10, 50019 Sesto Fiorentino (FI), Italy.

The rapid development of hardware and software for photoacoustic technologies is urging the establishment of dedicated tools for standardization and performance assessment. In particular, the fabrication of anatomical phantoms for photoacoustic imaging remains an open question, as current solutions have not yet gained unanimous support. Here, we propose that a hybrid material made of a water-in-oil emulsion of glycerol and polydimethylsiloxane may represent a versatile platform to host a broad taxonomy of hydrophobic and hydrophilic dyes and recapitulate the optical and acoustic features of bio tissue. For a full optical parameterization, we refer to Wróbel, [ Biomed. Opt. Express7, 2088 (2016)], where this material was first presented for optical imaging. Instead, here, we complete the picture and find that its speed of sound and acoustic attenuation resemble those of pure polydimethylsiloxane, i.e. respectively 1150 ± 30 m/s and 3.5 ± 0.4 dB/(MHz·cm). We demonstrate its use under a commercial B-mode scanner and a home-made A-mode stage for photoacoustic analysis to retrieve the ground-truth encoded in a multilayer architecture containing indocyanine green, plasmonic particles and red blood cells. Finally, we verify the stability of its acoustic, optical and geometric features over a time span of three months.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/BOE.10.003719DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6701555PMC
August 2019

1064-nm-resonant gold nanorods for photoacoustic theranostics within permissible exposure limits.

J Biophotonics 2019 10 2;12(10):e201900082. Epub 2019 Jun 2.

Istituto di Fisica Applicata 'Nello Carrara', Consiglio Nazionale delle Ricerche IFAC-CNR, Sesto Fiorentino, Italy.

Therapeutic and diagnostic methods based on photomechanical effects are attracting much current attention in contexts as oncology, cardiology and vascular surgery, for such applications as photoacoustic imaging or microsurgery. Their underlying mechanism is the generation of ultrasound or cavitation from the interaction of short optical pulses with endogenous dyes or targeted contrast agents. Among the latter, gold nanorods are outstanding candidates, but their use has mainly been reported for photoacoustic imaging and photothermal treatments. Conversely, much less is still known about their value as a precision tool for photomechanical manipulations, such as to impart local damage with high spatial resolution through the expansion and collapse of microbubbles. Here, we address the feasibility of gold nanorods exhibiting a distribution of surface plasmon resonances between about 900 to above 1100 nm as a contrast agent for photoacoustic theranostics. After testing their cytotoxicity and cellular uptake, we discuss their photostability and use to mediate cavitation and the photomechanical destruction of targeted cells. We find that the choice of a plasmonic band peaking around 1064 nm is key to enhance the translational potential of this approach. With respect to the standard alternative of 800 nm, at 1064 nm, relevant regulations on optical exposure are less restrictive and the photonic technology is more mature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201900082DOI Listing
October 2019

Polylysine as a functional biopolymer to couple gold nanorods to tumor-tropic cells.

J Nanobiotechnology 2018 May 31;16(1):50. Epub 2018 May 31.

Institute of Applied Physics 'N. Carrara', National Research Council of Italy, Via Madonna del Piano, 10, 50019, Sesto Fiorentino, Italy.

Background: The delivery of plasmonic particles, such as gold nanorods, to the tumor microenvironment has attracted much interest in biomedical optics for topical applications as the photoacoustic imaging and photothermal ablation of cancer. However, the systemic injection of free particles still crashes into a complexity of biological barriers, such as the reticuloendothelial system, that prevent their efficient biodistribution. In this context, the notion to exploit the inherent features of tumor-tropic cells for the creation of a Trojan horse is emerging as a plausible alternative.

Results: We report on a convenient approach to load cationic gold nanorods into murine macrophages that exhibit chemotactic sensitivity to track gradients of inflammatory stimuli. In particular, we compare a new model of poly-L-lysine-coated particles against two alternatives of cationic moieties that we have presented elsewhere, i.e. a small quaternary ammonium compound and an arginine-rich cell-penetrating peptide. Murine macrophages that are exposed to poly-L-lysine-coated gold nanorods at a dosage of 400 µM Au for 24 h undertake efficient uptake, i.e. around 3 pg Au per cell, retain the majority of their cargo until 24 h post-treatment and maintain around 90% of their pristine viability, chemotactic and pro-inflammatory functions.

Conclusions: With respect to previous models of cationic coatings, poly-L-lysine is a competitive solution for the preparation of biological vehicles of gold nanorods, especially for applications that may require longer life span of the Trojan horse, say in the order of 24 h. This biopolymer combines the cost-effectiveness of small molecules and biocompatibility and efficiency of natural peptides and thus holds potential for translational developments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12951-018-0377-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5984317PMC
May 2018

A multifunctional organosilica cross-linker for the bio-conjugation of gold nanorods.

Colloids Surf B Biointerfaces 2017 Sep 31;157:174-181. Epub 2017 May 31.

Institute of Applied Physics, National Research Council of Italy, Sesto Fiorentino, Italy.

We report on the use of organosilica shells to couple gold nanorods to functional peptides and modulate their physiochemical and biological profiles. In particular, we focus on the case of cell penetrating peptides, which are used to load tumor-tropic macrophages and implement an innovative drug delivery system for photothermal and photoacoustic applications. The presence of organosilica exerts subtle effects on multiple parameters of the particles, including their size, shape, electrokinetic potential, photostability, kinetics of endocytic uptake and cytotoxicity, which are investigated by the interplay of colorimetric methods and digital holographic microscopy. As a rule of thumb, as the thickness of organosilica increases from none to ∼30nm, we find an improvement of the photophysical performances at the expense of a deterioration of the biological parameters. Therefore, detailed engineering of the particles for a certain application will require a careful trade-off between photophysical and biological specifications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.colsurfb.2017.05.068DOI Listing
September 2017

Statistical detection of nanoparticles in cells by darkfield microscopy.

Phys Med 2016 Jul 2;32(7):938-43. Epub 2016 Jul 2.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, viale Pieraccini 6, I-50139 Florence, Italy.

In the fields of nanomedicine, biophotonics and radiation therapy, nanoparticle (NP) detection in cell models often represents a fundamental step for many in vivo studies. One common question is whether NPs have or have not interacted with cells. In this context, we propose an imaging based technique to detect the presence of NPs in eukaryotic cells. Darkfield images of cell cultures at low magnification (10×) are acquired in different spectral ranges and recombined so as to enhance the contrast due to the presence of NPs. Image analysis is applied to extract cell-based parameters (i.e. mean intensity), which are further analyzed by statistical tests (Student's t-test, permutation test) in order to obtain a robust detection method. By means of a statistical sample size analysis, the sensitivity of the whole methodology is quantified in terms of the minimum cell number that is needed to identify the presence of NPs. The method is presented in the case of HeLa cells incubated with gold nanorods labeled with anti-CA125 antibodies, which exploits the overexpression of CA125 in ovarian cancers. Control cases are considered as well, including PEG-coated NPs and HeLa cells without NPs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2016.06.007DOI Listing
July 2016

Preparation and Photoacoustic Analysis of Cellular Vehicles Containing Gold Nanorods.

J Vis Exp 2016 05 2(111). Epub 2016 May 2.

Institute of Applied Physics, Italian National Research Council.

Gold nanorods are attractive for a range of biomedical applications, such as the photothermal ablation and the photoacoustic imaging of cancer, thanks to their intense optical absorbance in the near-infrared window, low cytotoxicity and potential to home into tumors. However, their delivery to tumors still remains an issue. An innovative approach consists of the exploitation of the tropism of tumor-associated macrophages that may be loaded with gold nanorods in vitro. Here, we describe the preparation and the photoacoustic inspection of cellular vehicles containing gold nanorods. PEGylated gold nanorods are modified with quaternary ammonium compounds, in order to achieve a cationic profile. On contact with murine macrophages in ordinary Petri dishes, these particles are found to undergo massive uptake into endocytic vesicles. Then these cells are embedded in biopolymeric hydrogels, which are used to verify that the stability of photoacoustic conversion of the particles is retained in their inclusion into cellular vehicles. We are confident that these results may provide new inspiration for the development of novel strategies to deliver plasmonic particles to tumors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3791/53328DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4942024PMC
May 2016

Tuning the interactions of PEG-coated gold nanorods with BSA and model proteins through insertion of amino or carboxylate groups.

J Inorg Biochem 2015 Sep 6;150:120-5. Epub 2015 May 6.

Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, Sesto Fiorentino, 50019, Florence, Italy.

Gold nanorods (GNRs) are important platforms for biosensing and drug delivery. As for most nanomaterials, appropriate coatings such as polyethylene glycol (PEG) are needed to stabilize GNRs within biological fluids. We show here that the interactions of GNRs with proteins can be finely modulated through surface modification using PEG-containing chains bearing charged headgroups. Interestingly, introduction of amino or carboxylate groups produces relevant and differential changes in GNR interactions with three representative proteins: lysozyme, cytochrome c, and bovine serum albumin. These effects were explored through the direct monitoring of plasmonic bands of the GNRs and are supported by independent dynamic light scattering (DLS) and circular dichroism (CD) determinations. Notably, GNR-protein interactions observed for these charged GNRs can be almost completely reversed by salt addition. These observations demonstrate the importance of electrostatic effects in governing GNR-protein interactions, and provide a basis for new sensing and delivery platforms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jinorgbio.2015.04.016DOI Listing
September 2015

Detection of biomarkers for inflammatory diseases by an electrochemical immunoassay: the case of neopterin.

Talanta 2015 Mar 4;134:48-53. Epub 2014 Nov 4.

Università degli Studi di Firenze, Dipartimento di Chimica, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy; Istituto di Biochimica delle Proteine, Via P. Castellino 111, 80131 Napoli, Italy. Electronic address:

An electrochemical immunoassay for neopterin was developed using recently produced specific antibodies immobilized to protein A-coated magnetic beads in combination with differential pulse voltammetry and screen-printed array of electrodes. Neopterin-alkaline phosphatase conjugate was used as label in a competitive assay format. Multiplexed analysis of neopterin was demonstrated by replacing the traditional ELISA with electrochemical detection and the traditional plastic wells with screen-printed array of electrodes. The optimized electrochemical method, based on polyclonal antibodies, reached a limit of detection of 0.008 ng/mL with an average RSD %=10. Serum samples collected from patients with sepsis, healthy volunteers and other patients without a confirmed clinical diagnosis were also analyzed. The obtained results, compared with those of a commercial ELISA kit, had a significant correlation, showing the possibility to distinguish among the serum samples from ill or healthy subjects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2014.10.053DOI Listing
March 2015

Concave gold nanocube assemblies as nanotraps for surface-enhanced Raman scattering-based detection of proteins.

Nanoscale 2015 Feb;7(8):3474-80

Institute of Applied Physics "Nello Carrara", National Research Council, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy.

SERS detection of proteins is typically performed by using labeling agents with stable and high Raman scattering cross sections. This is a valuable approach for trace detection and quantification of a target protein but is unsuitable for inspecting its inherent structural and functional properties. On the other hand, direct SERS of proteins has been mainly devoted to the study of short peptides and aminoacid sequences or of prosthetic groups with intense Raman signals, which is of scarce interest for a thorough characterization of most proteins. Here we try to overcome these limitations by setting-up an effective platform for the structural SERS analysis of proteins. The platform consists of an extended bidimensional array of gold concave nanocubes (CNCs) supported on a PDMS film. CNCs are closely-packed through face-face and face-corner interactions generating a monolayered arrangement featuring well distributed nanoholes. Here the protein homogeneously experiences an E-field enhancement outward from the metal surfaces surrounding it, which causes a large number of vibrations to be contemporarily amplified. The proposed platform provides stable and detailed SERS spectra and confers rapidity and reproducibility to the analysis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4nr05704jDOI Listing
February 2015

In vitro assessment of antibody-conjugated gold nanorods for systemic injections.

J Nanobiotechnology 2014 Dec 5;12:55. Epub 2014 Dec 5.

Istituto di Fisica Applicata 'Nello Carrara', Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy.

Background: The interest for gold nanorods in biomedical optics is driven by their intense absorbance of near infrared light, their biocompatibility and their potential to reach tumors after systemic administration. Examples of applications include the photoacoustic imaging and the photothermal ablation of cancer. In spite of great current efforts, the selective delivery of gold nanorods to tumors through the bloodstream remains a formidable challenge. Their bio-conjugation with targeting units, and in particular with antibodies, is perceived as a hopeful solution, but the complexity of living organisms complicates the identification of possible obstacles along the way to tumors.

Results: Here, we present a new model of gold nanorods conjugated with anti-cancer antigen 125 (CA125) antibodies, which exhibit high specificity for ovarian cancer cells. We implement a battery of tests in vitro, in order to simulate major nuisances and predict the feasibility of these particles for intravenous injections. We show that parameters like the competition of free CA125 in the bloodstream, which could saturate the probe before arriving at the tumors, the matrix effect and the interference with erythrocytes and phagocytes are uncritical.

Conclusions: Although some deterioration is detectable, anti-CA125-conjugated gold nanorods retain their functional features after interaction with blood tissue and so represent a powerful candidate to hit ovarian cancer cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12951-014-0055-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266900PMC
December 2014

Size dependent biological profiles of PEGylated gold nanorods.

J Mater Chem B 2014 Sep 7;2(36):6072-6080. Epub 2014 Aug 7.

Institute of Applied Physics "Nello Carrara", National Research Council, Via Madonna del Piano 10, Sesto Fiorentino, 50019 Italy.

The perspective of introducing plasmonic particles for applications in biomedical optics is receiving much interest. However, their translation into clinical practices is delayed by various factors, which include a poor definition of their biological interactions. Here, we describe the preparation and the biological profiles of gold nanorods belonging to five different size classes with average effective radii between ∼5 and 20 nm and coated with polyethylene glycol (PEG). All these particles exhibit decent stability in the presence of representative proteins, low cytotoxicity and satisfactory compatibility with intravenous administration, in terms of their interference with blood tissue. However, the suspension begins to become unstable after a few days of exposure to blood proteins. Moreover, the cytotoxicity is a little worse for smaller particles, probably because their purification is more critical, while undesirable interactions with the mononuclear phagocyte system are minimal in the intermediate size range. Overall, these findings hold implications of practical relevance and suggest that PEGylated gold nanorods may be a versatile platform for a variety of biomedical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4tb00991fDOI Listing
September 2014

A simple method to disentangle nanoparticle optical properties by darkfield microspectroscopy.

Microsc Res Tech 2014 Nov 28;77(11):886-95. Epub 2014 Jul 28.

Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, I-50139, Florence, Italy.

We present a darkfield optical microspectroscopy technique devoted to the disentangled measurement of the absorption and scattering cross sections of nanoparticle (NP) samples with variable concentration. The robustness of the method, including the needed instrumental calibrations, is examined in detail by analyzing and quantifying the major sources of statistic and systematic errors. As an exemplary case, results are presented on a gold NP colloid. The technique takes advantage of a simple inverted microscope, coupled with a spectrograph and equipped with a darkfield condenser and a variable numerical aperture objective to obtain spectra either in darkfield or brightfield optical configurations. By adopting the Lambert-Beer (LB) equation modeling, we were able to disentangle and measure with a single setup the absorption, scattering, and extinction coefficients of the same sample by combining three spectra, obtained by opportunely varying the objective numerical aperture. Typical plasmonic resonances were recognized at approximately 520 and 750 nm. Optical coefficients were measured as a function of particle number density (0.04-3.94 µm(-3), corresponding to 40 µM-4 mM nominal Au concentration) and good linearity was verified up to ∼1.5 µm(-3) (∼1 mM Au). Moreover, extinction and scattering cross sections were quantified and the validity of the LB approximation was reviewed. Besides its applications to plasmonic NPs, this method may be appropriate for any colloid, provided there exists a characteristic spectral feature in the ultraviolet-visible-near infrared range. This technique may be exploited to localize NPs in biological samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jemt.22411DOI Listing
November 2014

mRNA sequencing of a novel NPHS2 intronic mutation in a child with focal and segmental glomerulosclerosis.

Saudi J Kidney Dis Transpl 2014 Jul;25(4):854-7

Pediatric Nephrology, Dialysis and Transplant Unit, Department of Pediatrics, University of Padua, Padua, Italy.

The NPHS2 gene encodes podocin, a membrane protein that acts as the structural scaffold in podocyte foot processes. NPHS2 mutations are associated with steroid-resistant nephrotic syndrome (SRNS), with the pathologic variant being focal and segmental glomerulosclerosis (FSGS), an emerging cause of end-stage renal disease in children. We describe a novel NPHS2 sequence variant in a girl with SRNS. Onset occurred at the age of seven years, with edema, hypo-proteinemia, hypoalbuminemia, hypercholesterolemia, hypertriglyceridemia and nephrotic proteinuria. Renal function was normal and autoimmunity markers were negative. Proteinuria failed to decrease after standard steroid therapy. Renal biopsy showed FSGS. Cyclosporine therapy was instituted, but no remission of proteinuria was achieved and chronic renal failure developed. Molecular analysis of the NPHS2 gene revealed a homozygous nucleotide substitution in position c.451+3A>T in intron 3-4. This nucleotide substitution has not been reported in the literature till date. The effect of the detected substitution on podocin protein was demonstrated by renal biopsy RNA extraction and cDNA amplification analysis. This technique had never been applied to a NPHS2 mutation. Based on these results, immunosuppressive drugs were discontinued and conservative therapy was undertaken.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4103/1319-2442.135180DOI Listing
July 2014

SIX1 gene: absence of mutations in children with isolated congenital anomalies of kidney and urinary tract.

J Nephrol 2014 Dec 5;27(6):667-71. Epub 2014 Jun 5.

Laboratory of Immunopathology and Molecular Biology of the Kidney, Women's and Children's Health Department, University of Padua, Via Giustiniani 3, 35128, Padua, Italy.

Background: Mutations in human SIX1 gene cause branchiootorenal or branchiootic syndrome. Six1 deficient mice exhibit uni- or bilateral renal hypoplasia or kidney agenesis. Furthermore a lack of Six1 gene in the ureter leads to hydroureter and hydronephrosis. These murine malformations resemble human kidney and urinary tract congenital anomalies (CAKUT), a group of diseases with a diverse anatomical spectrum which includes duplex collecting system as much as urethra kidney and ureteropelvic anomalies. Our study focuses on whether mutations or deletion of this gene may be associated with nonsyndromic CAKUT.

Methods: Fifty unrelated patients (13-21 years) with nonsyndromic CAKUT were retrospectively recruited for SIX1 sequence variations analysis, and compared to three subjects without malformative nephrouropathies (controls). SIX1 coding sequence was screened by high resolution melt analysis (HRMA) and by Sanger direct sequencing. A quantitative comparative real-time polymerase chain reaction (PCR) was later performed in order to detect the presence of SIX1 gene deletion.

Results: We did not find significant differences in the HRMA melting curves for each of the SIX1 coding exons between patients and controls, as also confirmed by Sanger direct sequencing. Moreover quantitative comparative real-time PCR for SIX1 and data normalization excluded total SIX1 gene deletion in our patients.

Conclusions: We did not find sequence variations in SIX1 coding regions or complete gene deletion in our CAKUT population. These results suggest that alterations in these sequences are unlikely to be a major cause of nonsyndromic CAKUT. Nevertheless, further studies are necessary to understand if altered SIX1 expression may play a role in human development of kidney and urinary tract congenital anomalies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40620-014-0112-xDOI Listing
December 2014

Quantitative readout of optically encoded gold nanorods using an ordinary dark-field microscope.

Nanoscale 2013 Oct;5(20):9645-50

INO-CNR, National Institute of Optics-CNR, Largo E. Fermi 6, Florence, Italy.

In this paper we report on a new use for dark-field microscopy in order to retrieve two-dimensional maps of optical parameters of a thin sample such as a cryptograph, a histological section, or a cell monolayer. In particular, we discuss the construction of quantitative charts of light absorbance and scattering coefficients of a polyvinyl alcohol film that was embedded with gold nanorods and then etched using a focused mode-locked Ti:Sapphire oscillator. Individual pulses from this laser excite plasmonic oscillations of the gold nanorods, thus triggering plastic deformations of the particles and their environment, which are confined within a few hundred nm of the light focus. In turn, these deformations modify the light absorbance and scattering landscape, which can be measured with optical resolution in a dark-field microscope equipped with an objective of tuneable numerical aperture. This technique may prove to be valuable for various applications, such as the fast readout of optically encoded data or to model functional interactions between light and biological tissue at the level of cellular organelles, including the photothermolysis of cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c3nr00726jDOI Listing
October 2013

Strategies for electrochemical detection in immunochemistry.

Bioanalysis 2009 Oct;1(7):1271-91

Università degli Studi di Firenze, Dipartimento di Chimica, Polo Scientifico, via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy.

In this review, the current status of research in electrochemical immunosensors is considered. We primarily focus on label-free and enzyme-labeled immunosensors, and the analytical capabilities of these devices are discussed. Moreover, the use of magnetic beads as new materials for immunosensors coupled with electrochemical sensing is also described, together with the application of new molecules such as aptamers as specific biorecognition elements. Examples of the applicability of these devices in solving various analytical problems in clinical, environmental and food fields are reported. Finally, the prospects for the further development of immunosensor technologies are shown.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4155/bio.09.106DOI Listing
October 2009

Upper urinary tract infections are associated with RANTES promoter polymorphism.

J Pediatr 2010 Dec 24;157(6):1038-1040.e1. Epub 2010 Sep 24.

Laboratory of Immunopathology and Molecular Biology of the Kidney, Department of Pediatrics Salus Pueri, University of Padua, Italy.

We evaluated the association between MCP-1, CCR2, RANTES, and CCR5 gene polymorphisms and upper urinary tract infection in 273 children recruited in Northeast Italy. Statistical analysis of RANTES-403 G>A genotype frequencies showed that children carrying the RANTES-403 G allele are at higher risk for urinary tract infection, irrespective of vesicoureteral reflux.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jpeds.2010.08.006DOI Listing
December 2010

Chitosan films doped with gold nanorods as laser-activatable hybrid bioadhesives.

Adv Mater 2010 Oct;22(38):4313-6

Institute of Applied Physics "Nello Carrara", National Research Council, Via Madonna del Piano 10, Sesto Fiorentino, 50019, Italy.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201002228DOI Listing
October 2010

Gold nanorods as new nanochromophores for photothermal therapies.

J Biophotonics 2011 Jan 1;4(1-2):64-73. Epub 2010 Mar 1.

Istituto di Fisica Applicata Nello Carrara, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10 Sesto Fiorentino 50019, Italy.

Results and perspectives on the biomedical exploitation of gold nanorods with plasmon resonances in the near infrared window are reported. The authors describe experimental studies of laser-activated nanoparticles in the direct welding of connective tissues, which may become a valuable technology in biomedicine. In particular, colloidal gold nanorods excited by diode laser radiation at 810 nm were used to mediate functional photothermal effects and weld eye's lens capsules and arteries. The preparation of biopolymeric matrices including gold nanorods is also described, as well as preliminary tests for their application in the closure of wounds in vessels and tendons. Finally, the use of these nanoparticles for future applications in the diagnosis, imaging and therapy of cancer is discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201000002DOI Listing
January 2011

The impact of eNOS, MTR and MTHFR polymorphisms on renal graft survival in children and young adults.

Nephrol Dial Transplant 2009 Sep 6;24(9):2931-7. Epub 2009 Apr 6.

Department of Paediatrics, University of Padua, Italy.

Background: The main cause of reduced long-term graft survival is chronic allograft injury. Cardiovascular risk factors such as hyperhomocysteinaemia, accumulation of asymmetric dimethylarginine, increased oxidative stress and decreased production of nitric oxide seem to play an important role. Functional polymorphisms of the endothelial isoform of nitric oxide synthase (NOS) gene cause an alteration in nitric oxide production. Nitric oxide levels, and thus oxidative stress, are also influenced by hyperhomocysteinaemia.

Methods: We carried out a genetic analysis of endothelial nitric oxide synthase (eNOS) 894G>T, methionine synthase (MTR) 2756A>G and methylenetetrahydrofolate reductase (MTHFR) 677C>T/1298A>C in 268 renal allograft recipient/donor (D/R) matches, with respect to long-term graft survival.

Results: While MTHFR 677C>T/1298A>G and MTR 2756A>G polymorphism distribution in both recipients (R) and donors (D) showed no significant difference between matches with loss of graft function and those with long-term graft survival, the frequency of the eNOS 894TT genotype of donors was significantly increased (P = 0.040) in matches with better graft survival. The multivariate analysis identified the eNOS 894 genotype and clinically acute rejection episodes as independent risk factors for graft loss (P = 0.0406 and P = 0.0093, respectively).

Conclusions: The association between eNOS 894G>T polymorphism of donors and graft survival seems to suggest a role for this gene in chronic allograft injury; however, further studies are needed to confirm this hypothesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ndt/gfp161DOI Listing
September 2009

Analytical performances of aptamer-based sensing for thrombin detection.

Anal Chem 2007 Apr 6;79(7):3016-9. Epub 2007 Mar 6.

Aptamer-based assays represent a modern and attractive approach in bioanalytical chemistry. The DNA thrombin aptamer has been extensively investigated, and the coupling of this aptamer to different transduction principles has demonstrated the wide applicability of aptamers as bioreceptors in bioanalytical assays. The goal of this work was to critically evaluate all the parameters that can influence the sensor performances by using the thrombin aptamer immobilized onto piezoelectric quartz crystals. The optimization of the immobilization and the binding protocol was of paramount importance, and improvements in analytical performances could be obtained by optimizing simple steps in immobilization and assay conditions. Moreover, the work demonstrated the possibility of using aptamer-based sensors in complex matrixes, opening the possibility of a real application to diagnostics or medical investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ac070096gDOI Listing
April 2007

Aptamer-based detection of plasma proteins by an electrochemical assay coupled to magnetic beads.

Anal Chem 2007 Feb;79(4):1466-73

Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.

The DNA thrombin aptamer has been extensively investigated, and the coupling of this aptamer to different transduction principles has demonstrated the wide applicability of aptamers as bioreceptors in bioanalytical assays. The goal of this work was to design an aptamer-based sandwich assay with electrochemical detection for thrombin analysis in complex matrixes, using a simple target capturing step by aptamer-functionalized magnetic beads. The conditions for the aptamer immobilization and for the protein binding have been first optimized by surface plasmon resonance, and then transferred to the electrochemical-based assay performed onto screen-printed electrodes. The assay was then applied to the analysis of thrombin in buffer, spiked serum, and plasma and high sensitivity and specificity were found. Moreover, thrombin was generated in situ in plasma by the conversion of its precursor prothrombin, and the formation of thrombin was followed at different times. The concentrations detected by the electrochemical assay were in agreement with a simulation software that mimics the formation of thrombin over time (thrombogram). The proposed work demonstrates that the high specificity of aptamers together with the use of magnetic beads are the key features for aptamer-based analysis in complex matrixes, opening the possibility of a real application to diagnostics or medical investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ac061879pDOI Listing
February 2007