A simple procedure to obtain nanodiamonds from leftover of HFCVD system for biological application
Carolina Ramos Hurtado · Cristiane da Costa Wachesk · Rafaela Campos Queiroz · Erenilda Ferreira de Macedo · Rebeca Falcão Borja de Oliveira Correia · Thalita Sani Taiario · Milton Faria Diniz · Alexandre Martins Isaias dos Santos · Thais Larissa do Amaral Montanheiro · Gabriela Ramos Hurtado · Vladimir Jesus Trava‑Airoldi · Dayane Batista Tada
A simple procedure to
obtain nanodiamonds from
leftover of HFCVD system for biological application
Carolina Ramos Hurtado · Cristiane da Costa Wachesk · Rafaela Campos Queiroz · Erenilda Ferreira de Macedo · Rebeca Falcão Borja de Oliveira Correia · Thalita Sani Taiario · Milton Faria Diniz · Alexandre Martins Isaias dos Santos · Thais Larissa do Amaral Montanheiro · Gabriela Ramos Hurtado · Vladimir Jesus Trava‑Airoldi · Dayane Batista Tada
Nanodiamonds (NDs) are amongst the most investigated carbon-based nanostructures due to their chemical stability and favorable mechanical properties. Despite the number of works on methods for NDs production, one of the main challenges is to achieve their colloidal stability in aqueous suspension. Additionally, NDs are normally obtained by expensive, complex and time-consuming process. Herein, it was presented a facile method to obtain NDs in aqueous suspension by using columnar structure diamond from Hot-Filament Chemical Vapour Deposition reactor (HFCVD). CVD diamond leftover thick film from CVDVale Company was used. Therefore, this method has the advantage of being not only practical but also cost-effective since it brings a profitable use of CVD diamond leftover. The Diamond thick film was submitted to ultrasonic cavitation in the presence and absence of ZrO2 microbeads in aqueous medium. The NDs hydrodynamic diameter and the stability in aqueous suspension were monitored by light scattering, size and morphology were analyzed by transmission electronic microscopy. Considering the wide application of NDs in biomedical devices, cytotoxicity of aqueous suspensions of NDs was evaluated against murine embryonic fibroblast cells. Furthermore, NDs were functionalized with hydrogen and carboxyl groups. NDs aqueous suspension of straight size distribution was obtained even in the absence of ZrO2 beads, indicating that they may be dispensable in order to decrease NDs size. NDs of average hydrodynamic diameter of 22 nm and − 35 mV of Zeta-potential were obtained after ultrasonic cavitation followed by 2 h of centrifugation, not demonstrating cytotoxicity to cells at very low (0.05–0.5 μg/mL) nor at higher concentrations (116 μg/mL). Nevertheless, NDs showed a moderate cytotoxicity at intermediary concentration range (0.5–2.2 μg/mL). From our knowledge, this is the first work that reports on a facile method for providing NDs aqueous suspension with high colloidal stability from HFCVD diamond leftover.
Abstract
Gold Nanoparticles Used as Protein Scavengers
Enhance Surface Plasmon Resonance Signal
Erenildo Ferreira de Macedo,
Daniela Maria Ducatti Formaggio,
Nivia Salles Santos and
Dayane Batista Tada
Although several researchers had reported on methodologies for surface plasmon resonance (SPR) signal amplification based on the use of nanoparticles (NPs), the majority addressed the sandwich technique and low protein concentration. In this work, a different approach for SPR signal enhancement based on the use of gold NPs was evaluated. The method was used in the detection of two lectins, peanut agglutinin (PNA) and concanavalin A (ConA). Gold NPs were functionalized with antibodies anti-PNA and anti-ConA, and these NPs were used as protein scavengers in a solution. After being incubated with solutions of PNA or ConA, the gold NPs coupled with the collected lectins were injected on the sensor containing the immobilized antibodies. The signal amplification provided by this method was compared to the signal amplification provided by the direct coupling of PNA and ConA to gold NPs. Furthermore, both methods, direct coupling and gold NPs as protein scavengers, were compared to the direct detection of PNA and ConA in solution. Compared to the analysis of free protein, the direct coupling of PNA and ConA to gold NPs resulted in a signal amplification of 10–40-fold and a 13-fold decrease of the limit of detection (LOD), whereas the use of gold NPs as protein scavengers resulted in an SPR signal 40–50-times higher and an LOD 64-times lower.
Keywords: surface plasmon resonance; gold nanoparticles; signal amplification; lectins; concanavalin A; peanut agglutinin
Abstract
Inhibition of Melanoma
metastasis by
dual-peptide PLGA nps
Denise Costa Arruda,
Thaís Dolzany de Oliveira,
Patrícia Harume Fukuda Cursino,
Vera Susana Carneiro Maia,
Rodrigo Berzaghi,
Luiz R. Travassos,
Dayane Batista Tada
Despite the positive results observed in vitro and in vivo, clinical trials with bioactive peptides are generally hampered by their fast degradation in the biological system. Two bioactive peptides, P20 (CSSRTMHHC) and the combined peptide C (CVNHPAFACGYGHTMYYHHYQHHL) have been identified as anticancer therapeutics. Combined peptide C consists of peptide C (CVNHPAFAC), a tumor‐homing peptide, conjugated to the antiangiogenic peptide HTMYYHHYQHHL with a GYG. In this work, PLGA NPs with peptide C were applied as a dual‐peptide carrier for application in cancer therapy. Peptide P20 was loaded into the NPs and combined peptide C was conjugated to the NPs surface. These NPs were evaluated as a therapeutic system to treat metastatic melanoma. In vivo assays showed that P20 encapsulation in PLGA NPs enhanced its antitumor activity. The inhibitory activity of P20‐PLGANPs was similar to the activity of non‐encapsulated P20 in a dose fivefold higher. The inhibitory activity was even higher when P20PLGA NPs were functionalized with combined peptide C. P20PLGAPepC NPs reduced in 28% the number of lung nodules in a syngeneic model of metastatic melanoma as compared to untreated animals. Additionally to the better tumor targeting and the in situ release of P20, it is expected that the therapeutic efficiency of the dual‐peptide PLGA NPs was further enhanced by a synergistic effect between P20 and combined peptide C. Our encouraging results showed that by enabling the co‐delivery of two peptides and promoting tumor targeting, PLGA NPs coupled with peptide C is a promising platform for peptide‐based cancer therapy.
Abstract
Photosensitizing nanoparticles and the modulation of ROS generation
The association of PhotoSensitizer (PS) molecules with nanoparticles (NPs) forming photosensitizing NPs, has emerged as a therapeutic strategy to improve PS tumor targeting, to protect PS from deactivation reactions and to enhance both PS solubility and circulation time. Since association with NPs usually alters PS photophysical and photochemical properties, photosensitizing NPs are an important tool to modulate ROS generation. Depending on the design of the photosensitizing NP, i.e., type of PS, the NP material and the method applied for the construction of the photosensitizing NP, the deactivation routes of the excited state can be controlled, allowing the generation of either singlet oxygen or other reactive oxygen species (ROS). Controlling the type of generated ROS is desirable not only in biomedical applications, as in Photodynamic Therapy where the type of ROS affects therapeutic efficiency, but also in other technological relevant fields like energy conversion, where the electron and energy transfer processes are necessary to increase the efficiency of photoconversion cells. The current review highlights some of the recent developments in the design of Photosensitizing NPs aimed at modulating the primary photochemical events after light absorption.
Abstract
Bimetallic nanoparticles enhance photoactivity of conjugated photosensitizer
Jéssica A Magalhães,
Adjaci U Fernandes,
Helena C Junqueira,
Bruna C Nunes,
Thais A F Cursino,
Daniela M D Formaggio,
Maurício da S Baptista and
Dayane B Tada.
Although photodynamic therapy (PDT) of cancer has been continuously improved, its efficiency is still limited by the high toxicity in the absence of irradiation, aggregation and deactivation by biomolecules of the most common photosensitizers (PS). The association of PS to nanoparticles (NPs) can be a promising tool to overcome these limitations and also to enhance PS tumoral selectivity. In addition, the association of PS to metallic NPs may provide the modulation of PS fluorescence and also the enhancement of PS photoactivity due to the electronic coupling with NPs plasmon effect. Adversely to the innumerous work on the coupling of PS to metallic NPs, the application of bimetallic NPs with this goal has not been explored yet. In this work we investigated the physicochemical properties and cytotoxicity of bimetallic gold-platinum NPs (AuPtNPs) conjugated to a chlorin molecule modified with a thiol group. Additionally, chlorin was coupled to AuNPs for comparative purposes since these have been the most commonly used NPs in PDT. The results showed that both platforms promoted the chlorin solubility in water which is crucial in biological applications. Despite the enhancement of photoactivity promoted by both NPs in comparison with chlorin in solution, chlorin-conjugated with AuPtNPs proved to be a more suitable platform for PDT application, since it showed a lower dark citotoxicity, as well as a higher generation of singlet oxygen and cell internalization compared with chlorin-conjugated AuNPs. It is important to highlight that this is the first work reporting on the enhancement of PS photoactivity by its conjugation to AuPtNPs.
Abstract
Effect of Lipid Coating on the Interaction Between Silica Nanoparticles
and Membranes
Dayane B. Tada,
Emanuel Suraniti,
Liane M. Rossi,
Carlos A. P. Leite,
Carla S. Oliveira,
Tathyana C. Tumolo,
Roberto Calemczuk,
Thierry Livache, and
Mauricio S. Baptista
Lipid coating is a method highly used to improve the biocompatibility of nanoparticles (NPs), even though its effect on the NP properties is still object of investigation. Herein, silica NPs containing methylene blue, which is a photosensitizer used in a variety of biomedical applications, were coated with a phospholipid bilayer. Regarding the photophysical properties, lipid-coating did not cause significant changes since bare and lipid-coated NPs presented very similar absorption spectra and generated singlet oxygen with similar efficiencies. However, NP interaction with cells and membrane mimics was totally different for bare and lipid-coated NPs. Lipid-coated NPs were distributed through the cell cytoplasm whereas bare NPs were detected only in some vacuolar regions within the cells. Since cellular uptake and cytolocalization are influenced by NP adsorption on cell membranes, the interaction of lipid-coated and bare NPs were studied on a membrane mimic, i. e., Hybrid Bilayer Membranes (HBMs) made of different compositions of negatively charged and neutral lipids. Interactions of bare and lipid-coated NPs with HBMs were analyzed by Surface Plasmon Resonance Imaging. Bare NPs presented high adsorption and aggregation on HBMs independently of the surface charge. Conversely, lipid-coated NPs presented less aggregation on the membrane surface and the adsorption was dependent on the charges of the NPs and of the HBMs. Our results indicated that NPs aggregation on the membrane surface can be modulated by lipid coating, which affects the cytosolic distribution of the NPs.
Abstract
In vivo toxicity and antimicrobial activity of AuPtbimetallic nanoparticles
Daniela Maria Ducatti Formaggio
Xisto Antonio de Oliveira Neto
Lina Dayse Alcântara Rodrigues
Vitor Martins de Andrade
Bruna C. Nunes
Mônica Lopes-Ferreira
Fabiana G. Ferreira
Cristiane C. Wachesk
Emerson R. Camargo
Katia Conceição
Dayane Batista Tada
Despite the potential antimicrobial activity of metallic nanoparticles, the increasing concerns about nanosafety have been holding back the use of these materials in therapeutics and biomedical devices. In the last years, several studies called attention to metallic nanoparticles toxicity. In the most part of in vitro studies performed with mammalian cells, metallic NPs reduced cell viability and induced genotoxicity and inflammatory responses. Bimetallic NPs have attracted great attention because they present distinct and even more advanced characteristics when compared to nanoparticles formed by a single metal. Recently, bimetallic NPs have emerged as an alternative to improve the antimicrobial activity of metallic nanoparticles, aiming at the broadening of the action spectrum and the reduction of the toxicity. However, the biocompatibility of bimetallic nanoparticles has been demonstrated only by in vitro studies. In the present work, the toxicity of AuPt nanoparticles was addressed both in vitro and in vivo. In addition, the antimicrobial activity of AuPt bimetallic nanoparticles has been evaluated in comparison with Au and Ag nanoparticles. The nanoparticles were characterized by ultraviolet-visible spectroscopy, dynamic light scattering, transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, and X-ray diffraction. The antimicrobial activity was studied against Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. The toxicity of nanoparticles was evaluated in vitro by analyzing their toxicity against human fibroblast cells (HS68 cell line) and in vivo by embryonic toxicity test in zebrafish (Danio rerio). The results confirmed the intrinsic antimicrobial activity of the three types of nanoparticles but different toxicity. Bimetallic nanoparticles showed enhanced antimicrobial activity in comparison with Au nanoparticles but lower antimicrobial activity compared with Ag nanoparticles. However, AuPt nanoparticles showed great advantage over Ag nanoparticles due to the absence of cytotoxicity and lower toxicity in vivo.