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1.
J Funct Biomater ; 15(6)2024 Jun 16.
Article in English | MEDLINE | ID: mdl-38921537

ABSTRACT

In this study, we investigate the antibacterial effect of silver atoms implanted into a thin surface layer of titanium at low energies using an alternative ion plating technology called Diversified Ion Plating. Silver atoms were incorporated into titanium samples using reactive low-voltage ion plating at 2 keV and 4 keV. Surface modifications and morphology were evaluated using wettability, profilometry measurements, and energy-dispersive spectroscopy. For a precise determination of the quantity and depth of implanted silver atoms on titanium surfaces, a combination of experimental techniques such as Rutherford Backscattering Spectrometry along with Monte Carlo simulations were utilized. To assess the antibacterial effects of the silver atoms incorporated into pure titanium surfaces, bacterial suspension immersion tests were performed with a standard strain of Staphylococcus aureus (ATCC 12600). The outcomes indicate that titanium surfaces implanted with silver atoms were more effective in inhibiting the growth of Staphylococcus aureus than pure titanium surfaces. Better results were found when the deposition was performed at 4 keV, indicating that a deeper implantation of silver, spanning a few nanometers, can result in a longer and more effective release of silver atoms. These findings suggest the potential for the development of new, cost-effective biomaterials, paving the way for improved implant materials in various health-related applications.

2.
J Forensic Sci ; 69(4): 1449-1455, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38706115

ABSTRACT

Highways, the lifeline of the Brazilian economy, transport approximately 75% of the country's economic activity, highlighting its importance. However, professional drivers, accustomed to long daily journeys, make use of tablets widely available in Gas Station, which are known as "Rebites," which could contain a mixture of legal and illegal compounds. Thus, this study aims at the chemical characterization of these through different analytical methods. Initially, we performed a comprehensive screening of compounds present in seven samples collected across the country using high-resolution mass spectrometry (HRMS). The findings revealed caffeine as the main compound, alongside theophylline, lidocaine, and clobenzorex, among others. In the next step, we employ quantitative nuclear magnetic resonance (qNMR) to quantify the caffeine content in the tablets. The results indicated a caffeine concentration ranging between 14% and 31% (m/m), which may imply a daily overdose of this compound from around four tablets. In summary, this investigation provides a chemical characterization of real samples of "Rebites" freely obtained along Brazilian highways. Caffeine emerged as the predominant active compound, with its concentration determined by qNMR analysis. The notable presence of caffeine, combined with other stimulants, depressants, and hallucinogens, underscores the need for strict quality control measures regarding "Rebites" to safeguard public health.


Subject(s)
Caffeine , Magnetic Resonance Spectroscopy , Mass Spectrometry , Brazil , Humans , Caffeine/analysis , Tablets , Illicit Drugs/analysis , Illicit Drugs/chemistry , Motor Vehicles , Truck Drivers
4.
Polymers (Basel) ; 15(22)2023 Nov 10.
Article in English | MEDLINE | ID: mdl-38006106

ABSTRACT

The radiological protection has the purpose of safeguarding the physical well-being of the user, preventing exposure to detrimental levels of ionizing radiation. This study introduces a novel, cost-effective category of lead-free elastomeric material designed for radiation shielding. The filler compounds utilized are notably lighter than conventional lead-based materials, enhancing user ergonomics during application. They comprise of a blend of barium sulfate combined or not with magnesium oxide with addition-cure liquid silicone rubber. To ensure the effectiveness of the radiation shielding, X-ray transmission measurements were performed for the different thicknesses of the materials and the results compared with Monte Carlo simulations. Additionally, the physical properties of the new materials, such as density, homogeneity, tensile strength, viscosity, and wettability, were also evaluated. The findings indicate that both materials fulfill the requirement for application in radiation protection garments.

5.
ACS Biomater Sci Eng ; 7(8): 3683-3695, 2021 08 09.
Article in English | MEDLINE | ID: mdl-34291900

ABSTRACT

Ti6Al4V is one of the most lightweight, mechanically resistant, and appropriate for biologically induced corrosion alloys. However, surface properties often must be tuned for fitting into biomedical applications, and therefore, surface modification is of paramount importance to carry on its use. This work compares the interaction between two different cell lines (L929 fibroblasts and osteoblast-like MG63) and medical grade Ti6Al4V after surface modification by plasma nitriding or thin film deposition. We studied the adhesion of these two cell lines, exploring which trends are consistent for cell behavior, correlating with osseointegration and in vivo conditions. Modified surfaces were analyzed through several physicochemical characterization techniques. Plasma nitriding led to a more pronounced increase in surface roughness, a thicker aluminum-free layer, made up of diverse titanium nitride phases, whereas thin film deposition resulted in a single-phase pure titanium nitride layer that leveled the ridged topography. The selective adhesion of osteoblast-like cells over fibroblasts was observed in nitrided samples but not in thin film deposited films, indicating that the competitive cellular behavior is more pronounced in plasma nitrided surfaces. The obtained coatings presented an appropriate performance for its use in biomedical-aimed applications, including the possibility of a higher success rate in osseointegration of implants.


Subject(s)
Coated Materials, Biocompatible , Alloys , Corrosion , Surface Properties , Cell Line , Animals , Mice , Humans
6.
J Biomater Appl ; 35(3): 353-370, 2020 09.
Article in English | MEDLINE | ID: mdl-32571172

ABSTRACT

Ti6Al4V used in biomedical applications still has several surface-related problems, such as poor bone compatibility and low wear resistance. In this work, the formation of a protective layer of titanium nitride obtained by plasma treatment in hollow cathode was studied, and the best experimental conditions were verified by a statistical factorial design of experiments. The samples were characterized in terms of their physical and chemical properties, correlating the effects of time (min) and temperature (°C). An achieved ideal condition was further analysed in terms of in vitro cytotoxicity, micro-abrasion, and electrochemical properties. The carried-out assessment has shown that nitrided condition has an improvement in wettability, microhardness, along with TixNy formation and roughness increment, when compared to pristine condition.


Subject(s)
Alloys/chemistry , Coated Materials, Biocompatible/chemistry , Plasma Gases/chemistry , Titanium/chemistry , Animals , Cell Survival , Corrosion , Electrochemical Techniques , Electrodes , Humans , Mice , Surface Properties , Temperature , Time Factors , Wettability
7.
Mater Sci Eng C Mater Biol Appl ; 102: 264-275, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31146999

ABSTRACT

Ultra-high molecular weight polyethylene (UHMWPE) is a prevailing bearing material applied in joint arthroplasty. Despite not being a novel biomaterial, its debris as consequence of long application and surface properties usually still lead to short lifespan. Many of the drawbacks are associated with sterilization methods that degrade the surface properties of UHMWPE. This work aims at improving the sterilizing treatment and also increasing material wettability, without losing bulk properties, which are essential for an orthopedic bearing. Cold plasma in hollow cathode setting was used for the material surface functionalization. Samples were characterized through contact angle (WCA), x-ray diffraction (XRD), optical microscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and profilometry. Optimal points based on immediate surface wettability, shelf time and sterilization efficacy were chosen for biocompatibility evaluation. When comparing cell viability through MTT among treated samples (OP1, OP2 and UV), a slight reduction in OP2 viability could be seen after 7 days incubation, which is also observed in Giemsa staining and SEM images. In late incubation, OP1 loses its hydrophilic character and displays higher cell adhesion than its counterparts UV and OP2. At the end, OP2 showed less cells growing over the biomaterial after 7 days exposition compared to OP1 and UV. OP1 presented a more hydrophobic surface and improved cell adhesion, differently from OP2 and UV, which maintained their wettability conditions in late incubation. Cell analysis results indicate that surface wetting influences cell morphology and consequent cell adhesion, in which more hydrophobic surfaces are shown to favor fibroblast adhesion properties.


Subject(s)
Chemical Phenomena , Fibroblasts/cytology , Plasma Gases/chemistry , Polyethylenes/chemistry , Sterilization , Analysis of Variance , Animals , Apoptosis , Cell Adhesion , Cell Line , Cell Proliferation , Cell Shape , Cell Survival , Electrodes , Fibroblasts/ultrastructure , Mice
8.
Anticancer Res ; 38(11): 6231-6236, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30396942

ABSTRACT

BACKGROUND/AIM: Colorectal cancer is a common type of cancer with reported resistance to treatment, in most cases due to loss of function of apoptotic and cell-cycle proteins. Piperlongumine (PPLGM) is a natural alkaloid isolated from Piper species, with promising anti-cancer properties. This study investigated whether PPLGM is able to induce cell death in colorectal carcinoma HCT 116 cells expressing wild-type or deficient in Bax, p21 or p53. MATERIALS AND METHODS: PPLGM was extracted from roots of Piper tuberculatum. Cell viability was determined by reduction of 3-(4,5-dimethilthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assay. Cell death was evaluated by acridine orange/ethidium bromide staining and flow cytometry. Plasmid cleavage activity and circular dichroism DNA interaction were also analyzed. RESULTS: PPLGM induced selective cell death in all cell lines (IC50 range from 10.7 to 13.9 µM) with an increase in the number of late apoptotic cells and different profiles in cell-cycle distribution. Plasmid DNA analysis showed that PPLGM does not interact directly with DNA. CONCLUSION: This paper suggests that PPLGM may be a promising candidate in colorectal cancer therapy.


Subject(s)
Colorectal Neoplasms/genetics , Cyclin-Dependent Kinase Inhibitor p21/genetics , Dioxolanes/pharmacology , Tumor Suppressor Protein p53/genetics , bcl-2-Associated X Protein/genetics , Apoptosis , Cell Proliferation/drug effects , Cell Survival/drug effects , Colorectal Neoplasms/drug therapy , Drug Screening Assays, Antitumor , Gene Expression Regulation, Neoplastic/drug effects , HCT116 Cells , Humans
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