Embryotoxicity and teratogenesis of orthodontic acrylic resin in zebrafish.

Objectives: This study investigated the in vivo embryotoxicity, teratogenic potential, and additional effects of orthodontic acrylic resin as well as its components, utilizing zebrafish as a model organism. The research focused on morphological, cardiac, behavioral, and cognitive evaluations that were performed on embryos and larval-stage animals subjected to chronic exposure. Materials and methods: Embryo and larval-stage zebrafish were categorized into five experimental groups, which were further subdivided into five subgroups. These subgroups included three specific doses for each tested substance, a control with the vehicle (0.1 % dimethyl sulfoxide in water), and an absolute control (water). Assessments were performed on day 5 post-fertilization, which included morphological, cardiac, behavioral, and cognitive evaluations. All experiments had a sample size of ten animals and were performed in triplicate. Survival and hatching rates were analyzed using the Kaplan-Meier test, while other measurements were assessed using one-way analysis of variance (ANOVA), followed by the Tukey post hoc test. Results: Statistically significant differences were observed between the control and treatment groups across all the tested substances for heart rate, cognitive responsiveness, and cellular apoptosis. However, survival, hatching rate, and other parameters exhibited no significant variation, except for the highest dose in the dibutyl phthalate group, which demonstrated a notable difference in survival. Conclusions: Chronic exposure to acrylic resin and its components may be associated with decreased cognitive ability and cardiac rhythm, as well as an increase in the level of cellular apoptosis in zebrafish.

Synthesis of New Ruthenium Complexes and Their Exploratory Study as Polymer Hybrid Composites in Organic Electronics.

Polymeric hybrid films, for their application in organic electronics, were produced from new ruthenium indanones in poly(methyl methacrylate) (PMMA) by the drop-casting procedure. Initially, the synthesis and structural characterization of the ruthenium complexes were performed, and subsequently, their properties as a potential semiconductor material were explored. Hence hybrid films in ruthenium complexes were deposited using PMMA as a polymeric matrix. The hybrid films were characterized by infrared spectrophotometry and atomic force microscopy. The obtained results confirmed that the presence of the ruthenium complexes enhanced the mechanical properties in addition to increasing the transmittance, favoring the determination of their optical parameters. Both hybrid films exhibited a maximum stress around 10.5 MPa and a Knoop hardness between 2.1 and 18.4. Regarding the optical parameters, the maximum transparency was obtained at wavelengths greater than 590 nm, the optical band gap was in the range of 1.73-2.24 eV, while the Tauc band gap was in the range of 1.68-2.17 eV, and the Urbach energy was between 0.29 and 0.50 eV. Consequently, the above comments are indicative of an adequate semiconductor behavior; hence, the target polymeric hybrid films must be welcomed as convenient candidates as active layers or transparent electrodes in organic electronics.

Enhancement of Mechanical Properties of High-Thermal-Conductivity Composites Comprising Boron Nitride and Poly(methyl methacrylate) Resin through Material Design Utilizing Hansen Solubility Parameters.

Materials for heat sinks in automotive heat dissipation systems must demonstrate both high thermal conductivity and stress resistance during assembly. This research proposes a composite material, comprised of thermally conductive ceramic fillers and matrix resins, as a suitable option for such application. The strategy for designing this material interface is directed with Hansen solubility parameters (HSP). A composite material featuring a honeycomb-like structure made of poly(methyl methacrylate) (PMMA) and boron nitride (BN) particles was successfully fabricated through press molding. This yielded a continuous BN network exhibiting high thermal conductivity and moderate mechanical strength. The HSP evaluation led to the suggestion of introducing highly polar functional groups into the matrix resin to enhance the affinity between PMMA resin and BN fillers. In line with this recommendation, a nitrile (CN) group─a highly polar group─was introduced to PMMA (CN-PMMA), significantly enhancing the composite's maximum bending stress without noticeably degrading other properties. Surface HSP evaluation through contact angle measurements revealed an "interface enrichment effect", with the CN groups concentrating at the resin-filler interface and effectively interacting with the surface functional groups on the BN particles, which resulted in an increase in the maximum bending stress. These findings emphasize the advantage of employing HSP methodologies in designing high-performance composite materials.

Weighted Mostar invariants of chemical compounds: An analysis of structural stability.

The concept of the weighted Mostar invariant is a mathematical tool used in chemical graph theory to study the stability of chemical compounds. Several recent studies have explored the weighted Mostar invariant of various chemical structures, including hydrocarbons, alcohols, and other organic compounds. One of the key advantages of the weighted Mostar invariant is that it can be easily computed for large and complex chemical structures, making it a valuable tool for studying the stability of a wide range of chemical compounds. This notion has been utilized to build novel approaches for forecasting chemical compound stability, such as machine learning algorithms. The focus of the paper is to demonstrate the weighted Mostar indices of three specific nanostructures: silicon dioxide (SIO2, poly-methyl methacrylate network (PMMA(s)), and melem chains (MC(h)). The authors seek to provide the findings of their investigation of these nanostructures using the weighted Mostar invariant.

PMMA dialyzers modulate both humoral and cell-mediate immune response to anti-COVID-19 vaccine (BNT162b2) in a cohort of chronic hemodialyzed patients.

Patients on hemodialysis (HD) have a high risk of death from COVID-19. We evaluated the humoral and cell-mediated immune response to BNT162b2 (Pfizer-BioNTech) vaccine in HD patients, comparing HD with Poly-methyl-methacrylate (PMMA) and HD with Polysulphone (PS). Samples were collected before vaccination (T0) and 14-days after the 2ndvaccine (T2) in a TG (TG, n = 16-Foggia) and in a VG (CG, n = 36-Novara). Anti-SARS-CoV-2-Ig were titrated in the cohort 2-weeks after the 2nddose of vaccine. In the Testing-Group, serum neutralizing antibodies (NAb) were assayed and PBMCs isolated from patients were thawed, counted and stimulated with SARS-CoV-2 IGRA stimulation tube set. All patients had a positive ab-response, except in a case. PMMA-patients had higher levels of anti-SARS-CoV-2 IgG (p = 0.031); VG data confirmed these findings (p < 0.05). NAb evaluation: PMMA patients passed the positive cut-off value, while in PS group only only 1/8 patient did not respond. PMMA patients showed higher percentages of anti-SARS-CoV-2 S1/RBD-Ig after a complete vaccine schedule (p = 0.028). Interferon-gamma release: PMMA patients showed significantly higher release of IFNγ (p = 0.014). The full vaccination course provided sufficient protection against SARS-CoV-2 across the entire cohort, regardless of dialyzer type. After vaccination, PMMA patients show a better immune response, both humoral and cellular, at the end of the vaccination course than PS patients.

Composite Nanomaterials Based on Polymethylmethacrylate Doped with Carbon Nanotubes and Nanoparticles: A Review.

Composite polymer materials have high strength and lightness, which makes them attractive for use in a variety of structures and products. The present article contains an overview of modern works devoted to the production of composite materials based on poly(methyl methacrylate) (PMMA) with improved characteristics. The possibility of obtaining such materials can be a key area for creating more efficient and durable products in various industries. Various methods were considered to improve the characteristics of PMMA by doping the polymer matrix with carbon nanotubes (CNTs), graphite, nanohydroxyapatite particles, micro-zirconia nanoparticles, titanium dioxide, etc. The possibilities of using the obtained composite materials in various industries such as aviation, automotive, construction, medical and others are discussed. This article also presents the results of our own research on the mechanisms of interaction of PMMA with single-layer CNTs, leading to the creation of a composite polymer system "PMMA+CNT", achieved using the modern quantum chemical method DFT. This article presents a review of the recent research on the effect of CNTs on the mechanical and electrically conductive properties of nanocomposite materials. The outcomes of this study can be important for the development of science and technology in various fields, from fundamental chemistry to applied scientific research.

The Effects of Ozone Sterilization on the Chemical and Mechanical Properties of 3D-Printed Biocompatible PMMA.

Since ozone is highly corrosive, it can substantially affect the mechanical and chemical properties of the materials; consequently, it could affect the applicability of those materials in medical applications. The effect of ozone sterilization on the chemical and mechanical properties of additively manufactured specimens of biocompatible poly(methyl-methacrylate) was observed. FDM 3D-printed specimens of biocompatible PMMA in groups of five were exposed to high concentrations of ozone generated by corona discharge for different durations and at different ozone concentrations inside an enclosed chamber with embedded and calibrated ozone, temperature, and humidity sensors. A novel approach using laser-induced fluorescence (LIF) and spark-discharge optical emission spectrometry (SD-OES) was used to determine an eventual change in the chemical composition of specimens. Mechanical properties were determined by testing the tensile strength and Young's modulus. A calibrated digital microscope was used to observe the eventual degradation of material on the surface of the specimens. SD-OES and LIF analysis results do not show any detectable sterilization-caused chemical degradation, and no substantial difference in mechanical properties was detected. There was no detectable surface degradation observed under the digital microscope. The results obtained suggest that ozone sterilization appears to be a suitable technique for sterilizing PMMA medical devices.

Preparation of Hydrophobic Au Catalyst and Application in One-Step Oxidative Esterification of Methacrolein to Methyl Methacrylate.

The water produced during the oxidative esterification reaction occupies the active sites and reduces the activity of the catalyst. In order to reduce the influence of water on the reaction system, a hydrophobic catalyst was prepared for the one-step oxidative esterification of methylacrolein (MAL) and methanol. The catalyst was synthesized by loading the active component Au onto ZnO using the deposition-precipitation method, followed by constructing the silicon shell on Au/ZnO using tetraethoxysilane (TEOS) to introduce hydrophobic groups. Trimethylchlorosilane (TMCS) was used as a hydrophobic modification reagent to prepare hydrophobic catalysts, which exhibited a water droplet contact angle of 111.2°. At a temperature of 80 °C, the hydrophobic catalyst achieved a high MMA selectivity of over 95%. The samples were characterized using XRD, N2 adsorption, ICP, SEM, TEM, UV-vis, FT-IR, XPS, and water droplet contact angle measurements. Kinetic analysis revealed an activation energy of 22.44 kJ/mol for the hydrophobic catalyst.

Antibacterial PVDF Coral-Like Hierarchical Structure Composite Film Fabrication for Self-Cleaning and Radiative Cooling Effect.

Passive radiative cooling (PRC) is a zero-energy-consumption technology that reflects sunlight and radiates heat to cold outer space. In this work, a porous poly(vinylidene fluoride)-poly(methyl methacrylate) (PVDF-PMMA) composite film is fabricated by decorating zinc-imidazolate metal-organic framework (MOF) (ZIF-8) particles obtained by phase inversion. Due to the competent scattering via the coral-like hierarchical structures and the vibration excitations of specific functional groups, the prepared film exhibits good solar reflectance (92.6%) and intermediate infrared emittance (99.1%), with an average sub-ambient cooling of 10.4 °C under a solar radiation intensity of 0.6 AM1.5. Additionally, poly(vinylidene fluoride) has a low surface energy, while the ZIF-8 particles and coral-like hierarchical structures enhance the surface roughness, endowing the surface with significant superhydrophobicity characterized by a water contact angle (WCA) of 157.5° and a sliding angle (SA) of 2°. These films exhibit excellent antibacterial properties. When the content of ZIF-8 particles in the film is 300 mg·L-1, the antibacterial rate reaches 100% after 1 h of treatment. Thus, the ZIF-8 porous poly(vinylidene fluoride)-poly(methyl methacrylate) composite (ZPPP) film has potential application prospects in areas with high health and environmental requirements, such as cold chain transportation and public spaces.

Preclinical Evaluation of Bioactive Small Intestinal Submucosa-PMMA Bone Cement for Vertebral Augmentation.

In vertebroplasty and kyphoplasty, bioinert poly(methyl methacrylate) (PMMA) bone cement is a conventional filler employed for quick stabilization of osteoporotic vertebral compression fractures (OVCFs). However, because of the poor osteointegration, excessive stiffness, and high curing temperature of PMMA, the implant loosens, the adjacent vertebrae refracture, and thermal necrosis of the surrounding tissue occurs frequently. This investigation addressed these issues by incorporating the small intestinal submucosa (SIS) into PMMA (SIS-PMMA). In vitro analyses revealed that this new SIS-PMMA bone cement had improved porous structure, as well as reduced compressive modulus and polymerization temperature compared with the original PMMA. Furthermore, the handling properties of SIS-PMMA bone cement were not significantly different from PMMA. The in vitro effect of PMMA and SIS-PMMA was investigated on MC3T3-E1 cells via the Transwell insert model to mimic the clinical condition or directly by culturing cells on the bone cement samples. The results indicated that SIS addition substantially enhanced the proliferation and osteogenic differentiation of MC3T3-E1 cells. Additionally, the bone cement's biomechanical properties were also assessed in a decalcified goat vertebrae model with a compression fracture, which indicated the SIS-PMMA had markedly increased compressive strength than PMMA. Furthermore, it was proved that the novel bone cement had good biosafety and efficacy based on the International Standards and guidelines. After 12 weeks of implantation, SIS-PMMA indicated significantly more osteointegration and new bone formation ability than PMMA. In addition, vertebral bodies with cement were also extracted for the uniaxial compression test, and it was revealed that compared with the PMMA-implanted vertebrae, the SIS-PMMA-implanted vertebrae had greatly enhanced maximum strength. Overall, these findings indicate the potential of SIS to induce efficient fixation between the modified cement surface and the host bone, thereby providing evidence that the SIS-PMMA bone cement is a promising filler for clinical vertebral augmentation.

The effects of antimicrobial photocatalytic nanoparticles on the flexural strength of orthodontic acrylic resins: A systematic review and meta-analysis.

BACKGROUND/PURPOSE: Orthodontic acrylic resins containing antimicrobial photocatalytic nanoparticles aims to reduce oral lesions including denture stomatitis and white spot lesions but they should not imperil its mechanical properties. This systematic review was done to evaluate the effect of various photocatalytic nanoparticles on the flexural strength (FS) of acrylic resins. MATERIALS AND METHODS: We systematically searched the PubMed/Medline, Cochrane Library, and Scopus databases from January 2018 to October 2023. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the quality of the studies was evaluated using the QUIN tool, which is specifically designed to assess the risk of bias in vitro studies. RESULTS: Following screening of 1016 initial records, 23 studies were deemed eligible for inclusion. The addition of photocatalytic nanoparticles, such as emodin (Emo), curcumin (Cur), Cur nisin (CurNis), zeolite/zinc oxide (Zeo/ZnO), and Ulva lactuca (U. lactuca), to acrylic resins resulted in a reduction in FS, with the extent of reduction dependent on the nanoparticle concentration. Specifically, the addition of Emo (≥0.5 %), Cur (≥0.5 %), CurNis (≥5 %), Zeo/ZnO (≥2), and U. lactuca (≥1 %) to acrylic resins significantly decreased FS. Conversely, the inclusion of ZnO and titanium dioxide (TiO2) in acrylic resins improved FS, but higher concentrations (≥5 % for TiO2) had a limited positive effect. CONCLUSION: Our study supports the use of low concentrations of photocatalytic nanoparticles, such as ZnO (≤2 %), TiO2 (≤3 %), Emo (≤0.5 %), Cur (≤0.5 %), CurNis (≤5 %), and U. lactuca (≤1 %), in orthodontic acrylic resins without compromising FS.

Machinability and Surface Properties of Cryogenic Poly(methyl methacrylate) Machined via Single-Point Diamond Turning.

Poly(methyl methacrylate) (PMMA), with a glass transition temperature (Tg) over 100 °C, shows good mechanical and optical properties and has broad applications after being machined with single-point diamond turning (SPDT) at room temperature. Because of the high Tg, current efforts mostly focus on optimizing machining parameters to improve workpiece precision without considering the modification of material properties. Cryogenic cooling has been proven to be an effective method in assisting ultra-precision machining for certain types of metals, alloys, and polymers, but has never been used for PMMA before. In this work, cryogenic cooling was attempted during the SPDT of PMMA workpieces to improve surface quality. The machinability and surface properties of cryogenically cooled PMMA were investigated based on the mechanical properties at corresponding temperatures. Nanoindentation tests show that, when temperature is changed from 25 °C to 0 °C, the hardness and Young's modulus are increased by 37% and 22%, respectively. At these two temperature points, optimal parameters including spindle speed, feed rate and cut depth were obtained using Taguchi methods to obtain workpieces with high surface quality. The surface quality was evaluated based on the total height of the profile (Pt) and the arithmetic mean deviation (Ra). The measurement results show that the values of Pt and Ra of the workpiece machined at 0 °C are 124 nm and 6 nm, respectively, while the corresponding values of that machined at 25 °C are 291 nm and 11 nm. The test data show that cryogenic machining is useful for improving the form accuracy and reducing the surface roughness of PMMA. Moreover, the relationship between temperature, material properties and machinability weas established with dynamic mechanical analysis (DMA) data and a theoretical model. This can explain the origin of the better surface quality of the cryogenic material. The basis of this is that temperature affects the viscoelasticity of the polymer and the corresponding mechanical properties due to relaxation. Then, the material property changes will affect surface profile formation during machining. The experimental results and theoretical analysis show that cryogenically cooled PMMA has good machinability and improved surface quality when using SPDT compared to that at ambient temperature.

Poly(methyl methacrylate) in Orthopedics: Strategies, Challenges, and Prospects in Bone Tissue Engineering.

Poly(methyl methacrylate) (PMMA) is widely used in orthopedic applications, including bone cement in total joint replacement surgery, bone fillers, and bone substitutes due to its affordability, biocompatibility, and processability. However, the bone regeneration efficiency of PMMA is limited because of its lack of bioactivity, poor osseointegration, and non-degradability. The use of bone cement also has disadvantages such as methyl methacrylate (MMA) release and high exothermic temperature during the polymerization of PMMA, which can cause thermal necrosis. To address these problems, various strategies have been adopted, such as surface modification techniques and the incorporation of various bioactive agents and biopolymers into PMMA. In this review, the physicochemical properties and synthesis methods of PMMA are discussed, with a special focus on the utilization of various PMMA composites in bone tissue engineering. Additionally, the challenges involved in incorporating PMMA into regenerative medicine are discussed with suitable research findings with the intention of providing insightful advice to support its successful clinical applications.

Polymeric Electronic Shielding Layer Enabling Superior Dendrite Suppression for All-Solid-State Lithium Batteries.

LiBH4 is one of the most promising candidates for use in all-solid-state lithium batteries. However, the main challenges of LiBH4 are the poor Li-ion conductivity at room temperature, excessive dendrite formation, and the narrow voltage window, which hamper practical application. Herein, we fabricate a flexible polymeric electronic shielding layer on the particle surfaces of LiBH4. The electronic conductivity of the primary LiBH4 is reduced by 2 orders of magnitude, to 1.15 × 10-9 S cm-1 at 25 °C, due to the high electron affinity of the electronic shielding layer; this localizes the electrons around the BH4- anions, which eliminates electronic leakage from the anionic framework and leads to a 68-fold higher critical electrical bias for dendrite growth on the particle surfaces. Contrary to the previously reported work, the shielding layer also ensures fast Li-ion conduction due to the fast-rotational dynamics of the BH4- species and the high Li-ion (carrier) concentration on the particle surfaces. In addition, the flexibility of the layer guarantees its structural integrity during Li plating and stripping. Therefore, our LiBH4-based solid-state electrolyte exhibits a high critical current density (11.43 mA cm-2) and long cycling stability of 5000 h (5.70 mA cm-2) at 25 °C. More importantly, the electrolyte had a wide operational temperature window (-30-150 °C). We believe that our findings provide a perspective with which to avoid dendrite formation in hydride solid-state electrolytes and provide high-performance all-solid-state lithium batteries.

New Methyl Methacrylate Derived Adsorbents - Synthesis, Characterization and Adsorptive Removal of Toxic Organic Compounds.

This study aimed to synthesize polymeric adsorbents by suspension polymerization using methyl methacrylate (MMA) with different crosslinking monomers. Divinylbenzene (DVB) and aliphatic monomers: ethylene glycol dimethacrylate (EGDMA) or N,N'-methylenebisacrylamide (NN) containing additional amide groups were used. The possibility of using the prepared copolymers (MMA-NN, MMA-EGDMA, MMA-DVB) as adsorbents for the removal of toxic compounds such as dyes (C.I. Acid Red 18 (AR18), C.I. Acid Green 16 (AG16), C.I. Acid Violet 1 (AV1), C.I. Basic Yellow 2 (BY2), C.I. Basic Blue 3 (BB3) and C.I. Basic Red 46 (BR46)) and phenol (PhOH) from dye baths and effluents was evaluated. Preferential adsorption of basic-type dyes compared to acid-type dyes or phenol was observed by the polymers. Adsorbent based on MMA-EGDMA exhibited the highest capacity for investigated dyes and phenol. The pseudo-second order kinetic model as well as the intraparticle diffusion model can find application in predicting sorption kinetics. Based on the equilibrium sorption data fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich model, uptake of BB3, AV1 and PhOH is rather physisorption than chemisorption. The regeneration yield of MMA-EGDMA does not exceed 60 % using 1 M HCl, 1 M NaCl, and 1 M NaOH in 50 %v/v methanol.

Coloration and Fire Retardancy of Transparent Wood Composites by Metal Ions.

Transparent wood composites (TWs) offer the possibility of unique coloration effects. A colored transparent wood composite (C-TW) with enhanced fire retardancy was impregnated by metal ion solutions, followed by methyl methacrylate (MMA) impregnation and polymerization. Bleached birch wood with a preserved hierarchical structure acted as a host for metal ions. Cobalt, nickel, copper, and iron metal salts were used. The location and distribution of metal ions in C-TW as well as the mechanical performance, optical properties, and fire retardancy were investigated. The C-TW coloration is tunable by controlling the metal ion species and concentration. The metal ions reduced heat release rates and limited the production of smoke during forced combustion tests. The potential for scaled-up production was verified by fabricating samples with a dimension of 180 × 100 × 1 (l × b × h) mm3.

Exploring the Molecular Origin for the Long-Range Propagation of the Substrate Effect in Unentangled Poly(methyl methacrylate) Films.

The polymer/substrate interface plays a significant role in the dynamics of nanoconfined polymers because of its suppression on polymer mobility and its long-range propagation feature, while the molecular origin of the long-range substrate effect in unentangled polymer material is still ambiguous. Herein, we investigated the propagation distances of the substrate effect (h*) by a fluorinated tracer-labeled method of two unentangled polymer films supported on silicon substrates: linear and ring poly(methyl methacrylate) films with relatively low molecular weights. The results indicate that the value of h* has a molecular weight dependence of h*∝N (N is the degree of polymerization) in the unentangled polymer films, while h*∝N1/2 was presented as previously reported in the entangled films. A theoretical model, depending on the polymer/polymer intermolecular interaction, was proposed to describe the above long-range propagation behavior of the substrate effect and agrees with our experiment results very well. From the model, it revealed that the intermolecular friction determines the long-range propagation of the substrate effect in the unentangled system, but the intermolecular entanglement is the dominant role in entangled system. These results give us a deeper understanding of the long-range substrate effect.

Is methyl methacrylate fixator reliable for the treatment of gartland type IV supracondylar fractures?

Background: In childhood supracondylar fractures of the humerus, fixation with percutaneous Kirschner wire is the standard treatment. In the case of irreducible-unstable fractures, these can be defined as fractures in which reduction is not well-achieved or in which fixation cannot be achieved with the K-wire. Intraoperative management of these types of fractures may be difficult. Treatment with a methyl methacrylate fixator consisting of K-wire and methyl methacrylate cement, as defined by the senior author of the article, may be a good option for Gartland type IV supracondylar humeral fractures where the fracture is unstable in flexion and extension due to complete periosteal tearing. Materials and Methods: The short-term and mid-term results of 27 patients between the ages of 4-12 with Gartland type IV supracondylar fracture of the humerus treated with methyl methacrylate fixation were reviewed. The patients were scored in terms of function and cosmetic satisfaction. Results: A total of 19 of the 27 patients treated with the methyl methacrylate fixator had full elbow motion function and rated the outcome of the treatment as excellent, which was judged by orthopedic surgeons on the basis of Flynn's criteria. Six patients had nearly full elbow motion and evaluated their recovery outcome as good. Two patients reported nearly full range of motion (ROM) and evaluated the method as moderate in terms of treatment. Discussion: Treatment with the methyl methacrylate fixation method is an inexpensive method that allows early joint mobilization, provides strong biomechanical stability, ensures good outcomes, and should be considered in the treatment of irreducible and unstable supracondylar fractures of the humerus.

Surface, mechanical and chemical properties of modified denture resin using natural biopolymer.

Objective: This laboratory study determined the surface, mechanical and chemical properties of polymethyl methacrylate (PMMA) denture resin reinforced with micron-sized Gum Arabic (GA) powder in different weight ratios. Methods: This laboratory study was conducted at the Dental Health Department of the College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia from November 2022 to February 2023. Three experimental denture resins were prepared by incorporating GA powder in heat-polymerized PMMA powder using different wt.% (5, 10, and 20 wt.%). While pristine PMMA served as the control group. A total of ten bar-shaped specimens with dimensions of 65 mm × 10 mm × 3.5 mm were prepared for each study group. The surface properties (micro CT and SEM evaluation), mechanical properties (Nanohardness, elastic modulus and flexural strength) and chemical properties (FTIR) were conducted. The data were statistically analyzed using the one-way analysis of variance and Tukey's post hoc tests (p<0.05). Results: The surface and bulk properties of experimental GA-reinforced PMMA resin materials deteriorated while the mechanical properties were also negatively altered using GA-based PMMA denture resin. A linear correlation was observed between weak mechanical properties and increasing wt.% of GA in denture resin. Conclusions: The incorporation of GA powder in denture resin might not be a viable option. The surface and mechanical properties of experimental PMMA composites were adversely affected compared to the control group.

Composition-Dependent Protein-Material Interaction of Poly(Methyl Methacrylate-co-styrene) Nanoparticle Series.

Polymer nanoparticles continue to be of high interest in life science applications. Still, adsorption processes occurring in protein-containing media and their implications for biological responses are not generally predictable. Here, the effect of nanoparticle composition on the adsorption of bovine serum albumin (BSA), fibronectin (FN) and immunoglobulin G (IgG) as structurally and functionally different model proteins was explored by systematically altering the composition of poly(methyl methacrylate-co-styrene) nanoparticles with sizes in a range of about 550 nm. As determined by protein depletion from the suspension medium via a colorimetric assay, BSA and IgG adsorbed at similar quantities, while FN reached larger masses of adsorbed protein (up to 0.4 ± 0.06 µg·cm-2 BSA, 0.42 ± 0.09 µg·cm-2 IgG, 0.72 ± 0.04 µg·cm-2 FN). A higher content of styrene as the more hydrophobic polymer component enhanced protein binding, which suggests a contribution of hydrophobic interactions despite the particles exhibiting strongly negatively charged surfaces with zeta potentials of -44 to -52 mV. The quantities of adsorbed proteins were estimated to correspond to a confluent surface coverage. Overall, this study illustrated how protein binding can be controlled by systematically varying the nanoparticle bulk composition and may serve as a basis for establishing interfaces with a targeted level of protein retention and/or presentation.