Immunotherapy for cancer: effects of iron oxide nanoparticles on polarization of tumor-associated macrophages.

Cancer immunotherapy is the most promising trend in oncology, focusing on helping or activating the patient's immune system to identify and fight against cancer. In the last decade, interest in metabolic reprogramming of tumor-associated macrophages from M2-like phenotype (promoting tumor progression) to M1-like phenotypes (suppressing tumor growth) as a therapeutic strategy against cancer has increased considerably. Iron metabolism has been standing out as a target for the reprogramming of tumor-associated macrophages to M1-like phenotype with therapeutic purposes against cancer. Due to the importance of the iron levels in macrophage polarization states, iron oxide nanoparticles can be used to change the activation state of tumor-associated macrophages for a tumor suppressor phenotype and as an anti-tumor strategy.

A new biocompatible silver/polypyrrole composite with in vitro antitumor activity.

We used an in situ chemical oxidation method to prepare a new composite of silver nanoparticles (AgNPs) with polypyrrole (PPy), whose properties were optimized through a 23-factorial design of the synthesis conditions. The successful formation of the AgNPs/PPy composite was confirmed by UV-Visible and FTIR spectroscopies. Transmission electron microscopy revealed the presence of AgNPs smaller than 100 nm, dispersed into the PPy matrix. This hybrid composite exhibits a blue fluorescence emission after excitation in the ultraviolet region. In MTT assays, the AgNPs/PPy composite exhibited low cytotoxicity toward non-tumoral cell lines (fibroblast, Vero, and macrophages) and selectively inhibited the viability of HeLa cells. The AgNPs/PPy composite induces ultrastructural changes in HeLa cells that are consistent with the noticeable selectivity exhibited toward them when compared to its action against non-tumoral cell lineages. Also, the AgNPs/PPy exhibited a hemolytic activity below 14% for all blood groups tested, at concentrations up to 125 µg/mL. These results suggest that the AgNPs/PPy composite has a promising potential for use as an antitumoral agent.

Metal-polymer hybrid nanomaterial for impedimetric detection of human papillomavirus in cervical specimens.

The human papillomavirus (HPV) is one of the main sexually transmitted pathogens that infect the anogenital epithelium and mucous membranes. HPV genotypes can be classified as high and low oncogenic risk, with infection by the former resulting in cervical cancer in approximately 100 % of the cases. In this work, we developed an ultrasensitive electrochemical biosensor for the detection and identification of different HPV genotypes. A nanostructured platform based on a matrix of polyaniline (PANI) containing gold nanoparticles (AuNps) was designed for the chemical immobilization of a DNA probe capable of recognizing different HPV types. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) were used to characterize the genosensor. The impedimetric responses indicate that the proposed sensor was able to detect HPV (types 6, 11, 16, 31, 33, 45, and 58) in cervical specimens (cDNA samples). We obtained different profiles of electrochemical responses for the high and low-risk HPV genotypes. By adopting a three-dimensional quantitative analysis of impedance response variables, it was possible to identify the existence of a pattern of association for samples of high oncogenic risk, which may lead to the differential diagnosis of HPV. The biosensor demonstrated an excellent analytical performance for the detection of HPV genotypes with high sensibility and selectivity. The genosensor exhibited a linear range of response in the 1 pg µL-1 to 100 pg µL-1 range. Besides, a limit of detection (LOD) of 2.74 pg µL-1 and 7.43 pg µL-1 was obtained for HPV11 and HPV16, respectively, with regression coefficients of 99.88 % and 99.47 %. Thus, the proposed sensor may serve as a good prognostic indicator for patients infected with papillomavirus.

Magnetic extraction and purification of DNA from whole human blood using a γ-Fe2O3@Chitosan@Polyaniline hybrid nanocomposite.

We examined the properties of the nanocomposite γ-Fe2O3@Chi@Pani as an adsorbent of deoxyribonucleic acid (DNA). As a model system, we used an aqueous solution of salmon sperm DNA, whose decreasing concentration was followed by monitoring the 260 nm UV-vis absorption. After adjusting the data collected to a Langmuir isotherm curve, we estimated the adsorption capacity (qe) of the nanocomposite as 49.5 mg/g. We also observed that the kinetic model of the DNA capture presents a mixed character, with both chemical mechanisms and intraparticle diffusion processes involved. When the MNC was used to extract the DNA from complex samples (human blood), a capture rate of 80 ng/µL was achieved, with the collected fraction exhibiting good quality, as evaluated by PCR analysis and electrophoresis assays. These results suggest that the γ-Fe2O3@Chi@Pani nanocomposite is a promising adsorbent for use in protocols for purification of DNA from complex samples.

Fabrication of Highly Flexible Hierarchical Polypyrrole/Carbon Nanotube on Eggshell Membranes for Supercapacitors.

Flexible batteries and supercapacitors (SCs) are expected to play a crucial role in energy storage and management in portable electronic devices. In addition, use of materials based on renewable resources would allow for more affordable and sustainable gadgets. In this context, eggshell membranes (ESMs) represent a promising functional platform for production of high-performance electronic components. In this work, we use ESMs for preparing flexible SCs through the incorporation of carbon nanotubes and subsequent in situ polymerization of polypyrrole, producing a highly conductive nanostructure characterized by a porous surface that exhibits both faradic and nonfaradic mechanisms for charge storage. We have found that by controlling the conducting polymer/carbon derivative relative concentration, one can maximize the corresponding capacitance to attain values up to the order 564.5 mF/cm2 (areal capacitance), 24.8 F/cm3 (volumetric capacitance), and 357.9 F/g (gravimetric capacitance). These bioinspired flexible devices exhibit a capacitance retention of 60% after 4000 cycles of charge/discharge and present negligible aging even after 500 bending repetitions (at a density of current 5 mA/cm2). The successful use of ESM-based electrodes in association with carbon derivatives/conducting polymers confirm that the exploit of biological materials offers a promising perspective for the development of new ecofriendly electronic devices.

Use of magnetic polyaniline/maghemite nanocomposite for DNA retrieval from aqueous solutions.

We demonstrated that the magnetic polyaniline/maghemite nanocomposite (Pani/γ-Fe2O3 MNC) is an efficient agent for retrieval of pure double stranded deoxyribonucleic acid (dsDNA) chains from aqueous solutions. The dsDNA chains used in the retrieval experiments were of sodium salt of Salmon Sperm DNA. Based on λ=260 nm absorption measurements, we have employed UV-Vis spectroscopy to estimate the concentration of DNA present in solutions, before and after the interaction with the MNC. The best results corresponded to a maximum amount of 75.2 mg of DNA absorbed per gram of MNC reached within only 10 min of joint exposure into the aqueous solution. After magnetic separation of the fully DNA-loaded Pani/γ-Fe2O3 MNC, we achieved essentially complete DNA desorption by appropriate changes in the pH of the solution. We have shown that it is possible to recycle the use of these MNC in several adsorption-desorption cycles. By comparing the present results to those of other DNA retrieval systems reported in the literature, we argued that the Pani/γ-Fe2O3 MNC here described represent a promising low-cost material for use as a fast, simple and efficient method of DNA separation and concentration.

A simple HPV 18 detection method based on ultra specific primer immobilized on glass slides.

This study was carried out to develop a simple and inexpensive method for detection of Human papillomavirus (HPV 18) based on irreversible immobilization of ultra specific primer on silanized glass slides. This method is revealed by Blue Green Loading Dye I (LGC) and compared with conventional polymerase chain reaction (PCR) for endocervical samples. The new method was tested in 40 DNA samples with precancer uterine lesions of women treated in Hospital of Recife PE, Brazil. DNA samples were extracted using Wizard Genomic DNA Purification Kit according to manufacturer's instructions. The samples were tested for HPV 18 by conventional PCR (PCRc) and the products visualized on 1.2% agarose gel, with LGC under UV 260 nm. After that the positive and negative samples to HPV 18 were tested by immobilization method and the results visualized with LGC under UV 260 nm. Both PCRc and immobilization method showed high degree of correlation (95%), whereas comparison between PCRc and immobilization method showed good correlation (100%). PCRc is widely known for detection of HPV because of its high sensitivity and efficiency, but due to high cost it is not yet standardized for use in public health laboratories. In our study, the single-stranded DNA immobilized method on a glass slide was effective in screening for HPV revealed by Blue Green and may be an alternative method for diagnosis of HPV once it offers a fast, and easy handling.