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1.
Mol Microbiol ; 116(3): 890-908, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34184334

RESUMO

The lipid mediators, platelet-activating factor (PAF) and lysophosphatidylcholine (LPC), play relevant pathophysiological roles in Trypanosoma cruzi infection. Several species of LPC, including C18:1 LPC, which mimics the effects of PAF, are synthesized by T. cruzi. The present study identified a receptor in T. cruzi, which was predicted to bind to PAF, and found it to be homologous to members of the progestin and adiponectin family of receptors (PAQRs). We constructed a three-dimensional model of the T. cruzi PAQR (TcPAQR) and performed molecular docking to predict the interactions of the TcPAQR model with C16:0 PAF and C18:1 LPC. We knocked out T. cruzi PAQR (TcPAQR) gene and confirmed the identity of the expressed protein through immunoblotting and immunofluorescence assays using an anti-human PAQR antibody. Wild-type and knockout (KO) parasites were also used to investigate the in vitro cell differentiation and interactions with peritoneal mouse macrophages; TcPAQR KO parasites were unable to react to C16:0 PAF or C18:1 LPC. Our data are highly suggestive that PAF and LPC act through TcPAQR in T. cruzi, triggering its cellular differentiation and ability to infect macrophages.


Assuntos
Lisofosfatidilcolinas/metabolismo , Fator de Ativação de Plaquetas/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/genética , Trypanosoma cruzi/metabolismo , Sequência de Aminoácidos , Animais , Diferenciação Celular , Doença de Chagas/parasitologia , Técnicas de Inativação de Genes/métodos , Interações Hospedeiro-Parasita , Humanos , Lisofosfatidilcolinas/química , Macrófagos , Camundongos , Simulação de Acoplamento Molecular , Filogenia , Fator de Ativação de Plaquetas/química , Conformação Proteica , Proteínas de Protozoários/química , Receptores de Adiponectina/química , Receptores de Adiponectina/genética , Receptores de Adiponectina/metabolismo , Receptores de Progesterona/química , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Trypanosoma cruzi/química
2.
Int J Mol Sci ; 23(4)2022 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-35216431

RESUMO

Blood-contacting devices are increasingly important for the management of cardiovascular diseases. Poly(ethylene glycol) (PEG) hydrogels represent one of the most explored hydrogels to date. However, they are mechanically weak, which prevents their use in load-bearing biomedical applications (e.g., vascular grafts, cardiac valves). Graphene and its derivatives, which have outstanding mechanical properties, a very high specific surface area, and good compatibility with many polymer matrices, are promising candidates to solve this challenge. In this work, we propose the use of graphene-based materials as nanofillers for mechanical reinforcement of PEG hydrogels, and we obtain composites that are stiffer and stronger than, and as anti-adhesive as, neat PEG hydrogels. Results show that single-layer and few-layer graphene oxide can strengthen PEG hydrogels, increasing their stiffness up to 6-fold and their strength 14-fold upon incorporation of 4% w/v (40 mg/mL) graphene oxide. The composites are cytocompatible and remain anti-adhesive towards endothelial cells, human platelets and Staphylococcus aureus, similar to neat hydrogels. To the best of our knowledge, this is the first work to report such an increase of the tensile properties of PEG hydrogels using graphene-based materials as fillers. This work paves the way for the exploitation of PEG hydrogels as a backbone material for load-bearing applications.


Assuntos
Grafite/química , Hidrogéis/química , Polietilenoglicóis/química , Adesivos/química , Materiais Biocompatíveis/química , Linhagem Celular , Células Endoteliais da Veia Umbilical Humana , Humanos , Polímeros/química , Engenharia Tecidual/métodos
3.
Parasitology ; 145(3): 355-370, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29039273

RESUMO

The species Phytomonas serpens is known to express some molecules displaying similarity to those described in trypanosomatids pathogenic to humans, such as peptidases from Trypanosoma cruzi (cruzipain) and Leishmania spp. (gp63). In this work, a population of P. serpens resistant to the calpain inhibitor MDL28170 at 70 µ m (MDLR population) was selected by culturing promastigotes in increasing concentrations of the drug. The only relevant ultrastructural difference between wild-type (WT) and MDLR promastigotes was the presence of microvesicles within the flagellar pocket of the latter. MDLR population also showed an increased reactivity to anti-cruzipain antibody as well as a higher papain-like proteolytic activity, while the expression of calpain-like molecules cross-reactive to anti-Dm-calpain (from Drosophila melanogaster) antibody and calcium-dependent cysteine peptidase activity were decreased. Gp63-like molecules also presented a diminished expression in MDLR population, which is probably correlated to the reduction in the parasite adhesion to the salivary glands of the insect vector Oncopeltus fasciatus. A lower accumulation of Rhodamine 123 was detected in MDLR cells when compared with the WT population, a phenotype that was reversed when MDLR cells were treated with cyclosporin A and verapamil. Collectively, our results may help in the understanding of the roles of calpain inhibitors in trypanosomatids.


Assuntos
Inibidores de Cisteína Proteinase/farmacologia , Dipeptídeos/farmacologia , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Peptídeo Hidrolases/efeitos dos fármacos , Trypanosomatina/efeitos dos fármacos , Calpaína/antagonistas & inibidores , Calpaína/química , Calpaína/efeitos dos fármacos , Calpaína/genética , Cisteína Endopeptidases/imunologia , Resistência a Medicamentos , Glicoproteínas/farmacologia , Leishmania/química , Leishmania/fisiologia , Proteínas de Membrana Transportadoras/genética , Peptídeo Hidrolases/genética , Proteínas de Protozoários/imunologia , Trypanosoma cruzi/química , Trypanosoma cruzi/fisiologia , Trypanosomatina/genética
4.
Acta Biomater ; 173: 351-364, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37984630

RESUMO

Developing biocompatible, non-fouling and biodegradable hydrogels for blood-contacting devices remains a demanding challenge. Such materials should promote natural healing, prevent clotting, and undergo controlled degradation. This study evaluates the biocompatibility and biodegradation of degradable poly(2-hydroxyethyl methacrylate) (d-pHEMA) hydrogels with or without reinforcement with oxidized few-layer graphene (d-pHEMA/M5ox) in a long term implantation in rats, assessing non-desired side-effects (irritation, chronic toxicity, immune response). Subcutaneous implantation over 6 months revealed degradation of both hydrogels, despite slower for d-pHEMA/M5ox, with degradation products found in intracellular vesicles. No inflammation nor infection at implantation areas were observed, and no histopathological findings were detected in parenchymal organs. Immunohistochemistry confirmed d-pHEMA and d-pHEMA/M5ox highly anti-adhesiveness. Gene expression of macrophages markers revealed presence of both M1 and M2 macrophages at all timepoints. M1/M2 profile after 6 months reveals an anti-inflammatory environment, suggesting no chronic inflammation, as also demonstrated by cytokines (IL-α, TNF-α and IL-10) analysis. Overall, modification of pHEMA towards a degradable material was successfully achieved without evoking a loss of its inherent properties, specially its anti-adhesiveness and biocompatibility. Therefore, these hydrogels hold potential as blank-slate for further modifications that promote cellular adhesion/proliferation for tissue engineering applications, namely for designing blood contacting devices with different load bearing requirements. STATEMENT OF SIGNIFICANCE: Biocompatibility, tunable biodegradation kinetics, and suitable immune response with lack of chronic toxicity and irritation, are key features in degradable blood contact devices that demand long-term exposure. We herein evaluate the 6-month in vivo performance of a degradable and hemocompatible anti-adhesive hydrogel based in pHEMA, and its mechanically reinforced formulation with few-layer graphene oxide. This subcutaneous implantation in a rat model, shows gradual degradation with progressive changes in material morphology, and no evidence of local inflammation in surrounding tissue, neither signs of inflammation or adverse reactions in systemic organs, suggesting biocompatibility of degradation products. Such hydrogels exhibit great potential as a blank slate for tissue engineering applications, including for blood contact, where cues for specific cells can be incorporated.


Assuntos
Grafite , Ratos , Animais , Grafite/farmacologia , Poli-Hidroxietil Metacrilato/química , Hidrogéis/farmacologia , Hidrogéis/química , Engenharia Tecidual , Inflamação , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/química
5.
ACS Appl Mater Interfaces ; 16(4): 4333-4347, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38240200

RESUMO

Nonmelanoma skin cancer (NMSC) is the most common cancer worldwide, among which 80% is basal cell carcinoma (BCC). Current therapies' low efficacy, side effects, and high recurrence highlight the need for alternative treatments. In this work, a partially reduced nanographene oxide (p-rGOn) developed in our laboratory was used. It has been achieved through a controlled reduction of nanographene oxide via UV-C irradiation that yields small nanometric particles (below 200 nm) that preserve the original water stability while acquiring high light-to-heat conversion efficiency. The latter is explained by a loss of carbon-oxygen single bonds (C-O) and the re-establishment of sp2 carbon bonds. p-rGOn was incorporated into a Carbopol hydrogel together with the anticancer drug 5-fluorouracil (5-FU) to evaluate a possible combined PTT and chemotherapeutic effect. Carbopol/p-rGOn/5-FU hydrogels were considered noncytotoxic toward normal skin cells (HFF-1). However, when A-431 skin cancer cells were exposed to NIR irradiation for 30 min in the presence of Carbopol/p-rGOn/5-FU hydrogels, almost complete eradication was achieved after 72 h, with a 90% reduction in cell number and 80% cell death of the remaining cells after a single treatment. NIR irradiation was performed with a light-emitting diode (LED) system, developed in our laboratory, which allows adjustment of applied light doses to achieve a safe and selective treatment, instead of the standard laser systems that are associated with damages in the healthy tissues in the tumor surroundings. Those are the first graphene-based materials containing pharmaceutical formulations developed for BCC phototherapy.


Assuntos
Grafite , Fotoquimioterapia , Neoplasias Cutâneas , Humanos , Grafite/química , Fluoruracila/farmacologia , Composição de Medicamentos , Linhagem Celular Tumoral , Fototerapia , Neoplasias Cutâneas/tratamento farmacológico , Carbono , Óxidos , Hidrogéis/farmacologia , Hidrogéis/química
6.
Small Methods ; : e2400857, 2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-38970553

RESUMO

Protein-based hydrogels have great potential to be used as bioinks for biofabrication-driven tissue regeneration strategies due to their innate bioactivity. Nevertheless, their use as bioinks in conventional 3D bioprinting is impaired due to their intrinsic low viscosity. Using embedding bioprinting, a liquid bioink is printed within a support that physically holds the patterned filament. Inspired by the recognized microencapsulation technique complex coacervation, crystal self-healing embedding bioprinting (CLADDING) is introduced based on a highly transparent crystal supporting bath. The suitability of distinct classes of gelatins is evaluated (i.e., molecular weight distribution, isoelectric point, and ionic content), as well as the formation of gelatin-gum arabic microparticles as a function of pH, temperature, solvent, and mass ratios. Characterizing and controlling this parametric window resulted in high yields of support bath with ideal self-healing properties for interaction with protein-based bioinks. This support bath achieved transparency, which boosted light permeation within the bath. Bioprinted constructs fully composed of platelet lysates encapsulating a co-culture of human mesenchymal stromal cells and endothelial cells are obtained, demonstrating a high-dense cellular network with excellent cell viability and stability over a month. CLADDING broadens the spectrum of photocrosslinkable materials with extremely low viscosity that can now be bioprinted with sensitive cells without any additional support.

7.
Cureus ; 15(1): e33599, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36788831

RESUMO

Biliary ascariasis is rare in non-endemic areas. This infection is associated with severe complications of the biliary tract, which can become a medical emergency. Treatment with oral anthelmintics is often effective, but, in some cases, surgery is required.  We describe an unusual case of ultrasound diagnosis of biliary ascariasis in the gallbladder in a patient who, besides residing in a low-prevalence area of the infection, did not present with biliary tract manifestations. We intend to raise awareness of this clinical entity in non-endemic areas, where this diagnosis is not usually considered. A brief review of the subject is also presented.

8.
ACS Biomater Sci Eng ; 9(6): 3712-3722, 2023 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-37256830

RESUMO

Triboelectric nanogenerators (TENGs) are associated with several drawbacks that limit their application in the biomedical field, including toxicity, thrombogenicity, and poor performance in the presence of fluids. By proposing the use of a hemo/biocompatible hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), this study bypasses these barriers. In contact-separation mode, using polytetrafluoroethylene (PTFE) as a reference, pHEMA generates an output of 100.0 V, under an open circuit, 4.7 µA, and 0.68 W/m2 for an internal resistance of 10 MΩ. Our findings unveil that graphene oxide (GO) can be used to tune pHEMA's triboelectric properties in a concentration-dependent manner. At the lowest measured concentration (0.2% GO), the generated outputs increase to 194.5 V, 5.3 µA, and 1.28 W/m2 due to the observed increase in pHEMA's surface roughness, which expands the contact area. Triboelectric performance starts to decrease as GO concentration increases, plateauing at 11% volumetric, where the output is 51 V, 1.76 µA, and 0.17 W/m2 less than pHEMA's. Increases in internal resistance, from 14 ΩM to greater than 470 ΩM, ζ-potential, from -7.3 to -0.4 mV, and open-circuit characteristic charge decay periods, from 90 to 120 ms, are all observed in conjunction with this phenomenon, which points to GO function as an electron trapping site in pHEMA's matrix. All of the composites can charge a 10 µF capacitor in 200 s, producing a voltage between 0.25 and 3.5 V and allowing the operation of at least 20 LEDs. The triboelectric output was largely steady throughout the 3.33 h durability test. Voltage decreases by 38% due to contact-separation frequency, whereas current increases by 77%. In terms of pressure, it appears to have little effect on voltage but boosts current output by 42%. Finally, pHEMA and pHEMA/GO extracts were cytocompatible toward fibroblasts. According to these results, pHEMA has a significant potential to function as a biomaterial to create bio/hemocompatible TENGs and GO to precisely control its triboelectric outputs.


Assuntos
Eletrônica Médica , Hidrogéis , Elétrons , Poli-Hidroxietil Metacrilato
9.
Acta Biomater ; 164: 253-268, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37121371

RESUMO

Degradable biomaterials for blood-contacting devices (BCDs) are associated with weak mechanical properties, high molecular weight of the degradation products and poor hemocompatibility. Herein, the inert and biocompatible FDA approved poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel was turned into a degradable material by incorporation of different amounts of a hydrolytically labile crosslinking agent, pentaerythritol tetrakis(3-mercaptopropionate). In situ addition of 1wt.% of oxidized graphene-based materials (GBMs) with different lateral sizes/thicknesses (single-layer graphene oxide and oxidized forms of few-layer graphene materials) was performed to enhance the mechanical properties of hydrogels. An ultimate tensile strength increasing up to 0.2 MPa (293% higher than degradable pHEMA) was obtained using oxidized few-layer graphene with 5 µm lateral size. Moreover, the incorporation of GBMs has demonstrated to simultaneously tune the degradation time, which ranged from 2 to 4 months. Notably, these features were achieved keeping not only the intrinsic properties of inert pHEMA regarding water uptake, wettability and cytocompatibility (short and long term), but also the non-fouling behavior towards human cells, platelets and bacteria. This new pHEMA hydrogel with degradation and biomechanical performance tuned by GBMs, can therefore be envisioned for different applications in tissue engineering, particularly for BCDs where non-fouling character is essential. STATEMENT OF SIGNIFICANCE: Suitable mechanical properties, low molecular weight of the degradation products and hemocompatibility are key features in degradable blood contacting devices (BCDs), and pave the way for significant improvement in the field. In here, a hydrogel with outstanding anti-adhesiveness (pHEMA) provides hemocompatibility, the presence of a degradable crosslinker provides degradability, and incorporation of graphene oxide reestablishes its strength, allowing tuning of both degradation and mechanical properties. Notably, these hydrogels simultaneously provide suitable water uptake, wettability, cytocompatibility (short and long term), no acute inflammatory response, and non-fouling behavior towards endothelial cells, platelets and bacteria. Such results highlight the potential of these hydrogels to be envisioned for applications in tissue engineered BCDs, namely as small diameter vascular grafts.


Assuntos
Grafite , Hidrogéis , Humanos , Hidrogéis/farmacologia , Poli-Hidroxietil Metacrilato , Grafite/farmacologia , Células Endoteliais , Materiais Biocompatíveis/farmacologia , Água
10.
Cureus ; 14(12): e32908, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36699756

RESUMO

Recurrent respiratory papillomatosis (RRP) is a rare manifestation of human papillomavirus (HPV) infection. It is characterized by relapsing bulky papillomas in the respiratory tract, which are usually benign in nature. We describe a challenging case of RRP in an HIV-infected patient with extensive pulmonary disease, presenting with worsening dyspnea. The interaction between HPV with HIV as a coinfection is still not completely understood, particularly the role of HIV-associated immunosuppression in RRP. Our main goal is to raise awareness of this clinical entity and to promote further studies on its management, particularly in specific populations such as HIV-infected individuals. A brief review of the theme is also presented.

11.
Cureus ; 14(11): e31787, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36579262

RESUMO

Mycobacterium marinum is a non-tuberculous mycobacteria present in natural and non-chlorinated bodies of water. It is a known fish pathogen but can also cause human disease. It usually causes cutaneous lesions but in rare cases may originate more invasive diseases with the involvement of deep structures. We describe three cases of patients with cutaneous infection by M. marinum evaluated in a tertiary care center, two with confirmed infection and one with a presumptive diagnosis based on clinical and epidemiological features. A brief bibliographic review of M. marinum infections is then presented to support the theme. We aim to alert one to the difficulties in establishing the correct diagnosis of this infection, emphasize the importance of a high degree of suspicion for its identification, and review the therapeutic management options.

12.
J Mater Sci Mater Med ; 22(9): 2053-63, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21755398

RESUMO

This study reports the use of tetraethylene glycol-terminated self-assembled monolayers (EG(4) SAMs) as a background non-fouling surface to study the effect of an 18 carbon ligand (C18) on albumin selective and reversible adsorption and subsequent platelet and leukocyte adhesion. Surface characterization techniques revealed an efficient immobilization of different levels of C18 ligand on EG(4) SAMs and an increase of surface thickness and hydrophobicity with the increase of C18 ligands. Albumin adsorption increased as the percentage of C18 ligands on the surface increased, but only 2.5%C18 SAMs adsorbed albumin in a selective and reversible way. Adherent platelets also increased with the amount of immobilized C18. Pre-immersion of samples in albumin before contact with platelets demonstrated an 80% decrease in platelet adhesion. Pre-immersion in plasma was only relevant for 2.5%C18 SAMs since this was the only surface to have less platelet adhesion compared to buffer pre-immersion. EG(4) SAMs adhered negligible amounts of leukocytes, but surfaces with C18 ligands have some adherent leukocytes. Except for 10%C18 SAMs, which increased leukocyte adhesion after albumin pre-adhesion, protein pre-immersion did not influence leukocyte adhesion. It has been shown that a surface with a specific surface concentration of albumin-binding ligands (2.5%C18 SAMs) can recruit albumin selectively and reversibly and minimize the adhesion of platelets, despite still adhering some leukocytes.


Assuntos
Albuminas/metabolismo , Plaquetas/citologia , Adesão Celular , Leucócitos/citologia , Adsorção , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
13.
Rev Biol Trop ; 59(4): 1553-7, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22208073

RESUMO

The former monotypic genus Oligoneuria Pictet was known solely by a female subimago of the type-species Oligoneuria anomala Pictet. A new species of the genus Oligoneuria from the Atlantic rainforest of Macaé, Rio de Janeiro is described. The description was based in males and females imagos of Oligoneuria macabaiba sp. nov. caught with light traps. This species presents similar wing venation, abdominal posterolateral spines, as well as a membranous extension on anterior portion of the head as seen in the genus. Based on features of the new species, the genus is herein redefined. The species represents the first record of the genus from Southeastern Brazil.


Assuntos
Insetos/anatomia & histologia , Insetos/classificação , Animais , Brasil , Feminino , Masculino , Árvores
14.
ACS Appl Mater Interfaces ; 13(28): 32662-32672, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34240610

RESUMO

The lack of small-diameter vascular grafts (inner diameter <5 mm) to substitute autologous grafts in arterial bypass surgeries has a massive impact on the prognosis and progression of cardiovascular diseases, the leading cause of death globally. Decellularized arteries from different sources have been proposed as an alternative, but their poor mechanical performance and high collagen exposure, which promotes platelet and bacteria adhesion, limit their successful application. In this study, these limitations were surpassed for decellularized umbilical cord arteries through the coating of their lumen with graphene oxide (GO). Placental and umbilical cord arteries were decellularized and perfused with a suspension of GO (C/O ratio 2:1) with ∼1.5 µm lateral size. A homogeneous GO coating that completely covered the collagen fibers was obtained for both arteries, with improvement of mechanical properties being achieved for umbilical cord decellularized arteries. GO coating increased the maximum force in 27%, the burst pressure in 29%, the strain in 25%, and the compliance in 10%, compared to umbilical cord decellularized arteries. The achieved theoretical burst pressure (1960 mmHg) and compliance (13.9%/100 mmHg) are similar to the human saphenous vein and mammary artery, respectively, which are used nowadays as the gold standard in coronary and peripheral artery bypass surgeries. Furthermore, and very importantly, coatings with GO did not compromise the endothelial cell adhesion but decreased platelet and bacteria adhesion to decellularized arteries, which will impact on the prevention of thrombosis and infection, until full re-endothetialization is achieved. Overall, our results reveal that GO coating has an effective role in the improvement of decellularized umbilical cord artery performance, which is a huge step toward their application as a small-diameter vascular graft.


Assuntos
Prótese Vascular , Materiais Revestidos Biocompatíveis/química , Grafite/química , Artérias Umbilicais/química , Aderência Bacteriana/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Córion/irrigação sanguínea , Feminino , Células Endoteliais da Veia Umbilical Humana , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Placenta/irrigação sanguínea , Gravidez
15.
Materials (Basel) ; 14(11)2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34070414

RESUMO

Nanostructured carriers have been widely used in pharmaceutical formulations for dermatological treatment. They offer targeted drug delivery, sustained release, improved biostability, and low toxicity, usually presenting advantages over conventional formulations. Due to its large surface area, small size and photothermal properties, graphene oxide (GO) has the potential to be used for such applications. Nanographene oxide (GOn) presented average sizes of 197.6 ± 11.8 nm, and a surface charge of -39.4 ± 1.8 mV, being stable in water for over 6 months. 55.5% of the mass of GOn dispersion (at a concentration of 1000 µg mL-1) permeated the skin after 6 h of exposure. GOn dispersions have been shown to absorb near-infrared radiation, reaching temperatures up to 45.7 °C, within mild the photothermal therapy temperature range. Furthermore, GOn in amounts superior to those which could permeate the skin were shown not to affect human skin fibroblasts (HFF-1) morphology or viability, after 24 h of incubation. Due to its large size, no skin permeation was observed for graphite particles in aqueous dispersions stabilized with Pluronic P-123 (Gt-P-123). Altogether, for the first time, Gon's potential as a topic administration agent and for delivery of photothermal therapy has been demonstrated.

16.
Biomater Sci ; 9(9): 3362-3377, 2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33949373

RESUMO

Thrombosis and infection are the leading causes of blood-contacting device (BCD) failure, mainly due to the poor performance of existing biomaterials. Poly(2-hydroxyethyl methacrylate) (pHEMA) has excellent hemocompatibility but the weak mechanical properties impair its use as a bulk material for BCD. As such, pHEMA has been explored as a coating, despite the instability and difficulty of attachment to the underlying polymer compromise its success. This work describes the hydrogel composites made of pHEMA and graphene-based materials (GBM) that meet the biological and mechanical requirements for a stand-alone BCD. Five GBM differing in thickness, oxidation degree, and lateral size were incorporated in pHEMA, revealing that only oxidized-GBM can reinforce pHEMA. pHEMA/oxidized-GBM composites are cytocompatible and prevent the adhesion of endothelial cells, blood platelets, and bacteria (S. aureus), thus maintaining pHEMA's anti-adhesive properties. As a proof of concept, the thrombogenicity of the tubular prototypes of the best formulation (pHEMA/Graphene oxide (GO)) was evaluated in vivo, using a porcine arteriovenous-shunt model. pHEMA/GO conduits withstand the blood pressure and exhibit negligible adhesion of blood components, revealing better hemocompatibility than ePTFE, a commercial material for vascular access. Our findings reveal pHEMA/GO, a synthetic and off-the-shelf hydrogel, as a preeminent material for the design of blood-contacting devices that prevent thrombosis and bacterial adhesion.


Assuntos
Grafite , Poli-Hidroxietil Metacrilato , Animais , Materiais Biocompatíveis/farmacologia , Células Endoteliais , Staphylococcus aureus , Suínos
17.
Zootaxa ; 4820(1): zootaxa.4820.1.11, 2020 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-33056089

RESUMO

A new species of Bessierus Thomas Orth, formerly a monotypic genus, is described from Amapá State, Brazil. The type species of the genus, B. doloris Thomas Orth, had only its nymphs described until recently, when its male imago was associated to nymphs mainly based on pigmentation pattern. Bessierus riobranco sp. n. here described has no significant difference on pigmentation pattern from B. doloris, thus the new species could be the male imago of B. doloris, and the putative imago of B. doloris a new species, or even both described imagoes could be new species. Still, a new male imago existence cannot be neglected and we opted to provide a properly description, diagnosis and illustration, hence contributing to the knowledge of mayfly neotropical diversity and future research on the genus. The generic concept of Bessierus and its type species diagnoses are altered to accommodate the new species, and a new record of B. doloris is provided.


Assuntos
Ephemeroptera , Animais , Brasil , Masculino , Ninfa , Pigmentação
18.
Zootaxa ; 4759(1): zootaxa.4759.1.7, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33056935

RESUMO

Three unusual nymphs of Euthyplociidae, subfamily Euthyplociinae, are described from Ecuador. A new genus and new species are established to accommodate these individuals. The morphologically unique specimens are defined by the following characters: short, stout tusks lacking spine-like setae but densely covered with long, hair-like setae; head almost as long as wide; long, quadrate clypeus with acute apicolateral projections; apex of 3rd segment of labial palp acute; apex of 3rd segment of maxillary palp acute and narrow. The hind wing is small, similar to that of Mesoplocia. An ongoing study of the phylogeny of the family recovers Dasyplocia gen. nov. as closely related to Euthyplocia and Mesoplocia.


Assuntos
Ephemeroptera , Animais , Equador , Ninfa , Filogenia , Asas de Animais
20.
ACS Appl Mater Interfaces ; 12(18): 21020-21035, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32233456

RESUMO

Graphene-based materials (GBMs) have been increasingly explored for biomedical applications. However, interaction between GBMs-integrating surfaces and bacteria, mammalian cells, and blood components, that is, the major biological systems in our body, is still poorly understood. In this study, we systematically explore the features of GBMs that most strongly impact the interactions of GBMs films with plasma proteins and biological systems. Films produced by vacuum filtration of GBMs with different oxidation degree and thickness depict different surface features: graphene oxide (GO) and few-layer GO (FLGO) films are more oxidized, smoother, and hydrophilic, while reduced GO (rGO) and few-layer graphene (FLG) are less or nonoxidized, rougher, and more hydrophobic. All films promote glutathione oxidation, although in a lower extent by rGO, indicating their potential to induce oxidative stress in biological systems. Human plasma proteins, which mediate most of the biological interactions, adsorb less to oxidized films than to rGO and FLG. Similarly, clinically relevant bacteria, Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, adhere less to GO and FLGO films, while rGO and FLG favor bacterial adhesion and viability. Surface features caused by the oxidation degree and thickness of the GBMs powders within the films have less influence toward human foreskin fibroblasts; all materials allow cell adhesion, proliferation and viability up to 14 days, despite less on rGO surfaces. Blood cells adhere to all films, with higher numbers in less or nonoxidized surfaces, despite none having caused hemolysis (<5%). Unlike thickness, oxidation degree of GBMs platelets strongly impact surface morphology/topography/chemistry of the films, consequently affecting protein adsorption and thus bacteria, fibroblasts and blood cells response. Overall, this study provides useful guidelines regarding the choice of the GBMs to use in the development of surfaces for an envisioned application. Oxidized materials appear as the most promising for biomedical applications that require low bacterial adhesion without being cytotoxic to mammalian cells.


Assuntos
Bactérias/efeitos dos fármacos , Materiais Biocompatíveis/química , Plaquetas/efeitos dos fármacos , Proteínas Sanguíneas/efeitos dos fármacos , Grafite/química , Adsorção , Proteínas Sanguíneas/química , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Proteínas Filagrinas , Humanos , Oxirredução , Propriedades de Superfície
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