Osteointegration of Ti Bone Implants: A Study on How Surface Parameters Control the Foreign Body Response.

The integration of titanium (Ti)-based implants with bone is limited, resulting in implant failure. This lack of osteointegration is due to the foreign body response (FBR) that occurs after the implantation of biodevices. The process begins with protein adsorption, which is governed by implant surface properties, e.g., chemistry, charge, wettability, and/or topography. The distribution and composition of the protein layer in turn influence the recruitment, differentiation, and modulation of immune and bone cells. The subsequent events that occur at the bone-material interface will ultimately determine whether the implant is encapsulated or will integrate with bone. Despite the numerous studies evaluating the influence of surface properties in the various stages of the FBR, the factors that affect tissue-material interactions are often studied in isolation or in small correlations due to the technical challenges involved in assessing them in vitro or in vivo. Consequently, the influence of protein conformation on the Ti bone implant surface design remains an unresolved research question. The objective of this review is to comprehensively evaluate the existing literature on the effect of surface parameters of Ti and its alloys in the stages of FBR, with a particular focus on protein adsorption and osteoimmunomodulation. This evaluation aims to systematically describe these effects on bone formation.

Enhancing silk fibroin structures and applications through angle-dependent Ar+ plasma treatment.

This study tackles limitations of Silk Fibroin (SF), including availability of sites for modification. This is achieved by Direct Plasma Nanosynthesis (DPNS), an Ar+ bombardment method, to generate and modify nanostructures and nanoscale properties on the SF surface. SF samples were treated with DPNS at incidence angles of 45o and 60o, with specific ion dose and energy parameters (1 × 1018 ions/cm2 and 500 eV, respectively) maintained throughout the process. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) primarily underscored transformations in SF's nitrogenous components. Specifically, treatment produced a boost in C-NH2, particularly pronounced in the 45o-treated samples, suggesting changes were more superficial than alterations to the secondary structure. The DPNS treatment gave rise to periodic nanocone structures on the SF surface, with a scale increase correlated to a higher angle of incidence. This resulted in a decrease in surface stiffness and significant changes in the motility of J774 macrophages interacting with the transformed SF. Furthermore, the SF samples treated at a 60o incidence showcased a confinement effect, moderating the macrophages' motility, morphology, and inflammatory response. The DPNS-induced alterations not only mitigate SF's limitations but also affect cellular behavior, expanding potential for SF in biomaterials.

Ion-bombardment-driven surface modification of porous magnesium scaffolds: Enhancing biocompatibility and osteoimmunomodulation.

Porous Mg scaffolds are promising for bone repair but are limited by high corrosion rates and challenges in preserving coating integrity. We used Directed Plasma Nanosynthesis (DPNS) at 400 eV and a fluence of 1 × 1018 cm-2 to augment the bioactivity and corrosion resistance of porous Mg scaffolds, maintaining their overall material integrity. DPNS creates nanostructures that increase surface area, promote apatite nucleation, and enhance osseointegration, improving the bioactivity and corrosion resistance of porous Mg scaffolds without compromising their structure. Our findings indicate a decrease in surface roughness, with pre-irradiated samples having Rq = 60.4 ± 5.3 nm andRa = 48.2 ± 3.1 nm, and post-DPNS samples showing Rq = 36.9 ± 0.3 nm andRa = 28.6 ± 0.8 nm. This suggests changes in topography and wettability, corroborated by the increased water contact angles (CA) of 129.2 ± 3.2 degrees. The complexity of the solution influences the CA: DMEM results in a CA of 120.4 ± 0.1 degrees, while DMEM + SBF decreases it to 103.6 ± 0.5 degrees, in contrast to the complete spreading observed in non-irradiated samples. DPNS-treated scaffolds exhibit significantly reduced corrosion rates at 5.7 × 10-3 ± 3.8 × 10-4 mg/cm²/day, compared to the control's 2.3 × 10-2 ± 3.2 × 10-4 mg/cm²/day over 14 days (P < 0.01). The treatment encourages the formation of a Ca-phosphate-rich phase, which facilitates cell spreading and the development of focal adhesion points in hBM-MSCs on the scaffolds. Additionally, J774A.1 murine macrophages show an enhanced immune response with diminished TNF-α cytokine expression. These results offer insights into nanoscale modifications of Mg-based biomaterials and their promise for bone substitutes or tissue engineering scaffolds.

Ion Bombardment-Induced Nanoarchitectonics on Polyetheretherketone Surfaces for Enhanced Nanoporous Bioactive Implants.

In spite of the biocompatible, nontoxic, and radiolucent properties of polyetheretherketone (PEEK), its biologically inert surface compromises its use in dental, orthopedic, and spine fusion industries. Many efforts have been made to improve the biological performance of PEEK implants, from bioactive coatings to composites using titanium alloys or hydroxyapatite and changing the surface properties by chemical and physical methods. Directed plasma nanosynthesis (DPNS) is an atomic-scale nanomanufacturing technique that changes the surface topography and chemistry of solids via low-energy ion bombardment. In this study, PEEK samples were nanopatterned by using argon ion irradiation by DPNS to yield active nanoporous biomaterial surface. PEEK surfaces modified with two doses of low and high fluence, corresponding to 1.0 × 1017 and 1.0 × 1018 ions/cm2, presented pore sizes of 15-25 and 60-90 nm, respectively, leaving exposed PEEK fibers and an increment of roughness of nearly 8 nm. The pores per unit area were closely related for high fluence PEEK and low fluence PEEK surfaces, with 129.11 and 151.72 pore/µm2, respectively. The contact angle significantly decreases in hydrophobicity-hydrophilicity tests for the irradiated PEEK surface to ∼46° from a control PEEK value of ∼74°. These super hydrophilic substrates had 1.6 times lower contact angle compared to the control sample revealing a rough surface of 20.5 nm only at higher fluences when compared to control and low fluences of 12.16 and 14.03 nm, respectively. These super hydrophilic surfaces in both cases reached higher cell viability with ∼13 and 34% increase, respectively, compared to unmodified PEEK, with an increased expression of alkaline phosphatase at 7 days on higher fluences establishing a higher affinity for preosteblasts with increased cellular activity, thus revealing successful and improved integration with the implant material, which can potentially be used in bone tissue engineering.

Analysis of Antibacterial Efficacy and Cellular Alignment Regulation on Plasma Nanotextured Chitosan Surfaces.

To address implant-related infections, antibacterial solutions specific to biomaterials are required to prevent bacterial proliferation. Traditional antibiotic usage has been found insufficient, motivating researchers to investigate alternative strategies such as surface modification and the application of antifouling or infection-resistant properties. A developing interest lies in designing surfaces that mimic natural antibacterial nanotopographies. In this study, we conducted a quantitative analysis of the outcomes from plasma nanotexturing, with particular emphasis on how the organization of topography influences antibacterial efficacy and the regulation of cell alignment. Plasma nanotexturing was applied to chitosan surfaces, which gradually transformed from nanopores to pillars and eventually into tilted pillars, as the plasma parameters (fluence and angle) increased. We used directed plasma nanosynthesis, a plasma-based technique that primarily induces topographical alterations on the surfaces. The surfaces were systematically characterized, incorporating methods such as scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). A comprehensive comparison of the nanotextures was executed by utilizing a trapezoidal method to calculate aspect ratios and assess texture orientation by examining the gaps in the nanostructures. We evaluated antibacterial properties against E. coli and S. aureus strains and assessed the survival and alignment of human bone marrow mesenchymal stem cells. Our findings reveal a significant reduction in bacterial adhesion (>80%) and growth on nanotextured surfaces, underscoring their potential for clinical applications. Moreover, we measured cell alignment, presenting the results in both a color-coded and numerical format to demonstrate the preferential alignment orientation induced specially by the tilted nanotexture. These insights highlight the profound impacts of plasma nanotexturing, indicating its potential for innovative biomedical applications such as advanced wound healing and tissue engineering.

Cytotoxicity and in vitro activity of chard (Beta vulgaris L. var Cicla) extracts on porcine pancreatic islets / Citotoxicidad y actividad in vitro de extractos de acelga (Beta vulgaris L. var Cicla) en islotes pacreáticos porcinosa / Citotocidae e atividade in vitro de extratos de acelga (Beta vulgaris L. var Cicla) em ilhotas pancreáticas porcinas

Background: reports from traditional medicine suggest that chard (Beta vulgaris L. var Cicla) can have remarkable effects in diabetes therapy. Objective: to evaluate the cytotoxic activity of chard extracts in cell lines and determine the viability of cultured porcine pancreatic islets added with or without chard extracts. Methods: cytotoxic activity of chard extracts was assessed in non-tumor and tumor cell lines using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] technique, and the ability of extracts to maintain porcine pancreatic islets viability and regeneration in vitro was tested. Results: the 50% cytotoxic concentration (CC50) of extracts for non-tumor cell lines was above 1,000 μg/mL, while it was 825 μg/mL, 283 μg/mL, 136 μg/mL and 380 μg/mL, for hexane, ethyl acetate, ethanol and water extracts in the tumor cell line, respectively. The CC50 ratio between cell lines indicates that ethanol extract is 7.5 times more toxic to tumor than non-tumor cell lines. There was an increase in viability of porcine pancreatic islets cultured with aqueous, ethyl acetate, and ethanol extracts compared with standard media (CMRL1066) and Cyclosporine A (CsA) control groups. Furthermore, a greater than one regeneration index of islets cultured with ethanol extract at 1,000 μg/mL and 500 μg/mL concentrations during 15 days was observed, which remained constant and was significantly higher than CsA group. Conclusions: these results suggest that chard metabolites should be researched to develop antitumor therapies and human pancreatic islets recovery in diabetes treatment.

Antecedentes: reportes de medicina tradicional sugieren que la planta acelga (Beta vulgaris L. var Cicla) es importante en el tratamiento de enfermedades como la diabetes. Objetivo: evaluar la citotoxicidad de concentraciones de extractos de acelga en líneas celulares y determinar la viabilidad de islotes pancreáticos porcinos cultivados con y sin extracto de acelga. Método: se evaluó la actividad citotóxica en líneas celulares tumorales y no tumorales, con la técnica del MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]. Específicamente se hicieron ensayos para comprobar si los extractos de acelga tienen la capacidad de mantener la viabilidad de islotes pancreáticos porcinos aislados e influir en su regeneración in vitro. Resultados: la concentración citotóxica al 50% (CC50) de los extractos en líneas no tumorales fue mayor de 1.000 μg/mL, mientras que para los extractos en hexano, acetato de etilo, etanol y agua fue de 825 μg/mL, 283 μg/mL, 136 μg/mL y 380 μg/mL, respectivamente, en líneas tumorales. La proporción CC50 encontrada indica que el extracto en etanol es 7,5 veces más tóxico para las líneas celulares tumorales que para las no tumorales. Igualmente encontramos un aumento en la viabilidad de los islotes pancreáticos porcinos cultivados con extracto acuoso, de acetato en etilo y etanol en comparación con el medio de cultivo estándar (CMRL1066) y un control inhibidor que contenía medio con Ciclosporina A (CsA). Además, se encontró que el índice de regeneración era mayor de uno en los islotes cultivados con el extracto en etanol a concentraciones de 1.000 μg/mL y 500 μg/mL durante 15 días, que se mantuvo constante y fue significativamente mayor en comparación con el grupo de CsA. Conclusión: estos resultados sugieren que los metabolitos de la acelga podrían ser utilizados en la investigación de nuevos fármacos para el desarrollo de terapias antitumorales y recuperación de islotes pancreáticos en el tratamiento de la diabetes.

Antecedentes: relatos encontrados em medicina sugerem que a planta acelga (Beta vulgaris L. var Cicla) tem un papel importante no tratamento das doenças como a diabetes. Objetivo: avaliar a citotoxicidade de concentrações de extratos em linhagens celulares e determinar a viabilidade de ilhotas pancreáticas de porcos cultivadas com e sem extrato de acelga. Métodos: neste trabalho foi avaliada a atividade citotóxica dos extratos da acelga em linhagens celulares tumorais e não tumorais, usando a técnica do MTT [3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide]; além disso, foram feitos ensaios para verificar a capacidade que têm os extratos para manter a viabilidade das ilhotas pancreáticas isoladas de porcos e a influência em sua regeneração in vitro. Resultados: a concentração citotóxica ao 50% (CC50) dos extratos em linhagens não tumorais está acima de 1000 μg/mL, enquanto para os extratos de hexano, acetato de etilo, etanol y água é de 825 μg/mL, 283 μg/mL, 136 μg/mL y 380 μg/mL, respectivamente, em linhagens tumorais. A proporção CC50 entre a célula indica que o extrato de etanol é 7,5 vezes mais tóxico para as linhas celulares tumorais que para as linhas não tumorais. Houve um aumento na viabilidade dos isolados pancreáticos de porcos cultivados com extrato aquoso, de acetato de etilo y etanol, em comparação com o meio de cultura padrão (CMRL 1066) e um controle inibitório contendo meio com Ciclosporina A (CsA). Encontrou-se também uma taxa de regeneração maior do que um em ilhotas cultivadas com concentrações de 1000 μg/mL e 500 μg/mL durante 15 días, que se manteve constante e foi significativamente mais elevada em comparação com a CsA. Conclusões: estes resultados sugerem que os metabolitos da acelga poderiam ser usados para a pesquisa de novas drogas para o desenvolvimento de terapias antitumorais e recuperação de ilhotas pancreáticas para o tratamento da diabetes.