Search Results (57)

This study aimed to comparatively evaluate the effects of various surface treatment protocols on the shear bond strength (SBS) between heat-polymerized polymethyl methacrylate (PMMA) and different CAD/CAM framework materials, including cobalt–chromium (Co–Cr) alloys, ceramic particle-reinforced polyetheretherketone (PEEK), and glass fiber-reinforced composite resin (FRC). A total of 135 disc-shaped specimens were prepared from Co–Cr, PEEK, and FRC materials. Surface treatments specific to each material, including airborne-particle abrasion, sulfuric acid etching, laser irradiation, plasma activation, and primer application, were applied. PMMA cylinders were polymerized onto the treated surfaces, and all specimens were subjected to 30,000 thermal cycles. SBS values were measured using a universal testing machine, and the failure modes were classified. The normality of data distribution was assessed using the Kolmogorov–Smirnov test, and the homogeneity of variances was evaluated using Levene’s test. Group comparisons were performed using the Kruskal–Wallis test, and Dunn’s post hoc test with Bonferroni correction was applied in cases where significant differences were detected (α = 0.05). The highest SBS values (~27–28 MPa) were obtained in the Co–Cr group and in the PEEK groups treated with sulfuric acid and primer. In contrast, the PEEK group with additional laser treatment exhibited a lower SBS value. The untreated PEEK group showed significantly lower SBS (~3.9 MPa) compared to all other groups. The Trinia groups demonstrated intermediate SBS values (16.5–17.4 MPa), which exceeded the clinically acceptable threshold of 10 MPa. SEM observations revealed material- and protocol-specific surface responses; plasma-treated specimens maintained topographic integrity, whereas laser-induced surfaces showed localized degradation, particularly following dual-step protocols. Fracture mode analysis indicated that higher SBS values were associated with cohesive or mixed failures. SEM observations suggested that plasma treatment preserved surface morphology more effectively than laser treatment. This study highlights the importance of selecting material-specific surface treatments to optimize bonding between CAD/CAM frameworks and PMMA. Sulfuric acid and primer provided strong adhesion for PEEK, while the addition of laser or plasma offered no further benefit, making such steps potentially unnecessary. Trinia frameworks also showed acceptable performance with conventional treatments. These findings reinforce that simplified conditioning protocols may be clinically sufficient, and indicate that FRC materials like Trinia should be more fully considered for their broader clinical potential in modern CAD/CAM-based prosthetic planning. Full article

Chemiresistive sensors integrated with functionalized conductive polymers have emerged as promising candidates for wearable applications, offering adequate protection against highly toxic and widely prevalent organophosphate compounds, due to their high sensitivity, room-temperature operation, and straightforward fabrication process. However, these chemiresistive sensors exhibit poor resistance to water vapor due to the intrinsic properties of these conducting polymers, likely leading to false sensor alarms. In this study, we engineered a series of water-vapor-resistant, yet organophosphate-sensitive, conducting polymers by electro-copolymerizing hexafluoroisopropanol (HFIP)-grafted 3,4-ethylenedioxythiophene (EDOT-HFIP) with EDOT comonomers bearing hydrophobic alkyl groups of varying lengths (ethyl, butyl, and hexyl). The typical results indicated that increasing the alkyl length and alkyl-bearing EDOT comonomer composition significantly enhanced the water resistance of the EDOT-HFIP copolymers and the copolymer-integrated chemiresistive sensor, but this improvement came at the unacceptable cost of compromising the organophosphate sensitivity. To address this issue, we developed a surface-driven phase-segregation strategy to enrich the alkyl chains on the surface while concentrating the HFIP groups beneath it by treating the silica substrates using oxygen plasma before polymer spin coating, thus decoupling and optimizing the two mutually competing characteristics. Finally, the chemiresistive sensor integrated with the EDOT-HFIP copolymer containing 10% hexyl-grafted EDOT comonomer exhibited an organophosphate (DMMP) resistive response 657 times higher than that to water vapor, and more than two times that of a PEDOT-HFIP sensor, while preserving the original specific sensitivity of the PEDOT-HFIP sensor. Furthermore, it demonstrated a markedly improved shelf storage stability, being directly exposed to air for 14 days without any special protection. We envision that this surface-driven phase-segregation strategy could offer a promising solution to the significant challenge of air moisture interference in highly sensitive polymer sensors, promoting their practical use in real-world applications. Full article

B-type natriuretic peptides (BNP) are produced and secreted by the myocardium to reduce blood pressure and cardiac load. They cause vasodilation, natriuresis, growth suppression, and inhibition of the sympathetic nervous system and the renin–angiotensin–aldosterone system. The measurement of plasma BNP levels provides clinically useful information concerning the diagnosis and management of left ventricular dysfunction and heart failure, complementing other diagnostic testing procedures. In this work, three epitopes from the N-terminal (BNPnt), C-terminal (BNPct), and the cystine-bridged cyclic peptides (BNPr) of B-type natriuretic peptides were synthesized as templates for molecular imprinting. These peptides were doped into aniline (AN) and m-aminobenzenesulfonic acid (MSAN) for electropolymerization, thus forming epitope-imprinted poly(AN-co-MSAN) conductive films (EIPs). The monomer ratio was optimized using the electrochemical signals during polymerization. The optimized films were then characterized using a scanning electron microscope (SEM), atomic force microscope (AFM), and AC impedance. The electrochemical response of the films to the target peptides and to BNP was then measured. The sensing range of the EIPs-coated electrodes was from 0.001 to 1000 pg/mL for BNP. Finally, the BNP concentration in diluted serum samples was measured with the BNPrIP-coated electrode, giving 3.15 ± 0.07 pg/mL. By spiking the sample with known BNP concentrations, the accuracy was determined to be better than ±5%. Full article

A new two-step method for developing a nanocomposite of polypropylene (PP) decorated with photocatalytically active TiO₂ nanoparticles (nTiO₂) is proposed. This method involves the low-temperature plasma functionalization of polypropylene followed by the ultrasound-assisted anchoring of nTiO₂. The nanoparticles, polymeric substrate, and resultant nanocomposite were thoroughly characterized using nanoparticle tracking analysis (NTA), microscopic observations (SEM, TEM, and EDX), spectroscopic investigations (XPS and FTIR), thermogravimetric analysis (TG/DTA), and water contact angle (WCA) measurements. The photocatalytic activity of the nanocomposites was evaluated through the degradation of methyl orange. The individual TiO₂ nanoparticles ranged from 2 to 6 nm in size. The oxygen plasma treatment of PP generated surface functional groups (mainly -OH and -C=O), transforming the surface from hydrophobic to hydrophilic, which facilitated the efficient deposition of nTiO₂. Optimized plasma treatment and sonochemical deposition parameters resulted in an active photocatalytic nTiO₂/PP system, degrading 80% of the methyl orange under UVA irradiation in 200 min. The proposed approach is considered versatile for the functionalization of polymeric materials with photoactive nanoparticles and, in a broader perspective, can be utilized for the fabrication of self-cleaning surfaces. Full article

Zn²⁺ has a crucial role both in biology and the environment, while Pb²⁺ presents serious hazards in the same areas due to its toxicity, and the need for their analysis often exceeds available instrumental capacity. We report, herein, a new high-throughput optochemical screening method for Zn²⁺ and Pb²⁺ in various solutions. Moreover, we also introduced a new and generalizable three-step-microplate-modification technique, including plasma treating, linker-docking and photocatalytic copolymerization. The surface of a commercially available 96-well-cycloolefin-microplate was treated with atmospheric plasma, and then, the bottoms of the wells were covered by covalently attaching a methacrylate-containing linker-monolayer. Finally, the preactivated microplate wells were covalently functionalized by immobilizing bis(acridino)-crown ether-type sensor molecules, via photocatalytic copolymerization, to a polymethacrylate backbone. This sensing tool can be used in all microplate readers, is compatible with liquid handling platforms and provides an unprecedently fast monitoring (>1000 samples/hour, extrapolated from the time required for 96 measurements) of dissolved Zn²⁺ and Pb²⁺ among recent alternatives above the detection limits of 8.0 × 10⁻⁹ and 3.0 × 10⁻⁸ mol/L, respectively, while requiring a sample volume of only 20 µL. Full article

Polylactic acid (PLA), as a renewable and biodegradable green polymer material, is hailed as one of the most promising biopolymers capable of replacing petroleum-derived polymers for industrial applications. Nevertheless, its limited toughness, thermal stability, and barrier properties have restricted its extensive application. To address these drawbacks in PLA, research efforts have primarily focused on enhancing its properties through copolymerization, blending, and plasticization. Notably, the blending of modified biomass with PLA is expected not only to effectively improve its deficiencies but also to maintain its biodegradability, creating a fully green composite with substantial developmental prospects. This review provides a comprehensive overview of modified biomass-reinforced PLA, with an emphasis on the improvements in PLA’s mechanical properties, thermal stability, and barrier properties achieved through modified cellulose, lignin, and starch. At the end of the article, a brief exploration of plasma modification of biomass is presented and provides a promising outlook for the application of reinforced PLA composite materials in the future. This review provides valuable insights regarding the path towards enhancing PLA. Full article

Currently, there is considerable interest in seeking an environmentally friendly technique that is neither thermally nor organic solvent-dependent for producing advanced polymer films for food-packaging applications. Among different approaches, plasma polymerization is a promising method that can deposit biodegradable coatings on top of polymer films. In this study, an atmospheric-pressure aerosol-assisted plasma deposition method was employed to develop a poly(ethylene glycol) (PEG)-like coating, which can act as a potential matrix for antimicrobial agents, by envisioning controlled-release food-packaging applications. Different plasma operating parameters, including the input power, monomer flow rate, and gap between the edge of the plasma head and substrate, were optimized to produce a PEG-like coating with a desirable water stability level and that can be biodegradable. The findings revealed that increased distance between the plasma head and substrate intensified gas-phase nucleation and diluted the active plasma species, which in turn led to the formation of a non-conformal rough coating. Conversely, at short plasma–substrate distances, smooth conformal coatings were obtained. Furthermore, at low input powers (<250 W), the chemical structure of the precursor was mostly preserved with a high retention of C-O functional groups due to limited monomer fragmentation. At the same time, these coatings exhibit low stability in water, which could be attributed to their low cross-linking degree. Increasing the power to 350 W resulted in the loss of the PEG-like chemical structure, which is due to the enhanced monomer fragmentation at high power. Nevertheless, owing to the enhanced cross-linking degree, these coatings were more stable in water. Finally, it could be concluded that a moderate input power (250–300 W) should be applied to obtain an acceptable tradeoff between the coating stability and PEG resemblance. Full article

The primary objective of this study was to assess the potential utility of quince seed mucilage as an excipient within a graft copolymer for the development of an oral-controlled drug delivery system. The Cydonia oblonga-mucilage-based graft copolymer was synthesized via a free radical polymerization method, employing potassium per sulfate (KPS) as the initiator and N, N-methylene bisacrylamide (MBA) as the crosslinker. Various concentrations of monomers, namely acrylic acid (AA) and methacrylic acid (MAA), were used in the graft copolymerization process. Metoprolol tartarate was then incorporated into this graft copolymer matrix, and the resultant drug delivery system was subjected to comprehensive characterization using techniques such as Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The swelling behavior of the drug delivery system was evaluated under different pH conditions, and in vitro drug release studies were conducted. Furthermore, pharmacokinetic parameters including the area under the curve (AUC), maximum plasma concentration (Cmax), time to reach Cmax (Tmax), and half-life (t1/2) were determined for metoprolol-loaded hydrogel formulations in rabbit plasma, and these results were compared with those obtained from a commercially available product. The key findings from the study include observations that higher concentrations of acrylic acid (AA) and Cydonia oblonga mucilage (CM) in the graft copolymer enhanced swelling, while the opposite trend was noted at elevated concentrations of methacrylic acid (MAA) and N, N-methylene bisacrylamide (MBA). FTIR analysis confirmed the formation of the graft copolymer and established the compatibility between the drug and the polymer. SEM imaging revealed a porous structure in the prepared formulations. Additionally, the swelling behavior and drug release profiles indicated a pH-sensitive pattern. The pharmacokinetic assessment revealed sustained release patterns of metoprolol from the hydrogel network system. Notably, the drug-loaded formulation exhibited a higher Cmax (156.48 ng/mL) compared to the marketed metoprolol product (96 ng/mL), and the AUC of the hydrogel-loaded metoprolol was 2.3 times greater than that of the marketed formulation. In conclusion, this study underscores the potential of quince seed mucilage as an intelligent material for graft-copolymer-based oral-controlled release drug delivery systems. Full article

Breast cancer (BC) is one of the most common types of cancer disease worldwide and it accounts for thousands of deaths annually. Lapatinib is among the preferred drugs for the treatment of breast cancer. Possible drug toxicity effects of lapatinib can be controlled by real-time determination of the appropriate dose for a patient at the point of care. In this study, a novel highly sensitive polymeric nanobiosensor for lapatinib is presented. A composite of poly(anilino-co-4-aminobenzoic acid) co-polymer {poly(ANI-co-4-ABA)} and coffee extract-based green-synthesized indium nanoparticles (InNPs) was used to develop the sensor platform on a screen-printed carbon electrode (SPCE), i.e., SPCE||poly(ANI-co-4-ABA-InNPs). Cytochrome P450-3A4 (CYP3A4) enzyme and polyethylene glycol (PEG) were incorporated on the modified platform to produce the SPCE||poly(ANI-co-4-ABA-InNPs)|CYP3A4|PEG lapatinib nanobiosensor. Experiments for the determination of the electrochemical response characteristics of the nanobiosensor were performed with cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The nanobiosensor calibration for 0–100 ng/mL lapatinib was linear and gave limit of detection (LOD) values of 13.21 ng/mL lapatinib and 18.6 ng/mL lapatinib in physiological buffer and human serum, respectively. The LOD values are much lower than the peak plasma concentration (C_max) of lapatinib (2.43 µg/mL), which is attained 4 h after the administration of a daily dose of 1250 mg lapatinib. The electrochemical nanobiosensor also exhibited excellent anti-interference performance and stability. Full article

Curcumin is a polyphenolic compound, derived from Curcuma longa, and it has several pharmacological effects such as antioxidant, anti-inflammatory, and antitumor. Although it is a pleiotropic molecule, curcumin’s free form, which is lipophilic, has low bioavailability and is rapidly metabolized, limiting its clinical use. With the advances in techniques for loading curcumin into nanostructures, it is possible to improve its bioavailability and extend its applications. In this review, we gather evidence about the comparison of the pharmacokinetics (biodistribution and bioavailability) between free curcumin (Cur) and nanostructured curcumin (Cur-NPs) and their respective relationships with antitumor efficacy. The search was performed in the following databases: Cochrane, LILACS, Embase, MEDLINE/Pubmed, Clinical Trials, BSV regional portal, ScienceDirect, Scopus, and Web of Science. The selected studies were based on studies that used High-Performance Liquid Chromatography (HPLC) as the pharmacokinetics evaluation method. Of the 345 studies initially pooled, 11 met the inclusion criteria and all included studies classified as high quality. In this search, a variety of nanoparticles used to deliver curcumin (polymeric, copolymeric, nanocrystals, nanovesicles, and nanosuspension) were found. Most Cur-NPs presented negative Zeta potential ranging from −25 mV to 12.7 mV, polydispersion index (PDI) ranging from 0.06 to 0.283, and hydrodynamic diameter ranging from 30.47 to 550.1 nm. Selected studies adopted mainly oral and intravenous administrations. In the pharmacokinetics analysis, samples of plasma, liver, tumor, lung, brain, kidney, and spleen were evaluated. The administration of curcumin, in nanoparticle systems, resulted in a higher level of curcumin in tumors compared to free curcumin, leading to an improved antitumor effect. Thus, the use of nanoparticles can be a promising alternative for curcumin delivery since this improves its bioavailability. Full article

Despite substantial improvements in breast cancer (BC) treatment there is still an urgent need to find alternative treatment options to improve the outcomes for patients with advanced-stage disease. Photodynamic therapy (PDT) is gaining a lot of attention as a BC therapeutic option because of its selectivity and low off-target effects. However, the hydrophobicity of photosensitizers (PSs) impairs their solubility and limits the circulation in the bloodstream, thus representing a major challenge. The use of polymeric nanoparticles (NPs) to encapsulate the PS may represent a valuable strategy to overcome these issues. Herein, we developed a novel biomimetic PDT nanoplatform (NPs) based on a polymeric core of poly(lactic-co-glycolic)acid (PLGA) loaded with the PS meso-tetraphenylchlorin disulfonate (TPCS_2a). TPCS_2a@NPs of 98.89 ± 18.56 nm with an encapsulation efficiency percentage (EE%) of 81.9 ± 7.92% were obtained and coated with mesenchymal stem cells-derived plasma membranes (mMSCs) (mMSC-TPCS_2a@NPs, size of 139.31 ± 12.94 nm). The mMSC coating armed NPs with biomimetic features to impart long circulation times and tumor-homing capabilities. In vitro, biomimetic mMSC-TPCS_2a@NPs showed a decrease in macrophage uptake of 54% to 70%, depending on the conditions applied, as compared to uncoated TPCS_2a@NPs. Both NP formulations efficiently accumulated in MCF7 and MDA-MB-231 BC cells, while the uptake was significantly lower in normal breast epithelial MCF10A cells with respect to tumor cells. Moreover, encapsulation of TPCS_2a in mMSC-TPCS_2a@NPs effectively prevents its aggregation, ensuring efficient singlet oxygen (¹O₂) production after red light irradiation, which resulted in a considerable in vitro anticancer effect in both BC cell monolayers (IC₅₀ < 0.15 µM) and three-dimensional spheroids. Full article

During the last few decades, many studies have focused on the development of environmentally friendly, efficient, and miniaturized sample preparation methods. In this study, solid-phase microextraction and electromembrane extraction methods were integrated to take advantage of both methods and achieve higher extraction recoveries and clean-up. In this regard, Cu/Cr layered double hydroxide was dispersed in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) polymerization mixture, and in situ polymerization was performed in the acceptor phase channel. Thereafter, EME-SPME on a chip was developed to extract non-steroidal anti-inflammatory drugs. The obtained limits of detection were 0.1–0.25 ng mL⁻¹. Under evaluation of this method, extraction recoveries were obtained in the range of 83.34–90.87%, which corresponded to preconcentration factors of 56–61. The method was applied for the extraction of the drugs from real samples such as breast milk, urine, and plasma, and satisfactory results were obtained. Full article

In the present work, Pebax-1657, a commercial multiblock copolymer (poly(ether-block-amide)), consisting of 40% rigid amide (PA6) groups and 60% flexible ether (PEO) linkages, was selected as the base polymer for preparing dense flat sheet mixed matrix membranes (MMMs) using the solution casting method. Carbon nanofillers, specifically, raw and treated (plasma and oxidized) multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were incorporated into the polymeric matrix in order to improve the gas-separation performance and polymer’s structural properties. The developed membranes were characterized by means of SEM and FTIR, and their mechanical properties were also evaluated. Well-established models were employed in order to compare the experimental data with theoretical calculations concerning the tensile properties of MMMs. Most remarkably, the tensile strength of the mixed matrix membrane with oxidized GNPs was enhanced by 55.3% compared to the pure polymeric membrane, and its tensile modulus increased 3.2 times compared to the neat one. In addition, the effect of nanofiller type, structure and amount to real binary CO₂/CH₄ (10/90 vol.%) mixture separation performance was evaluated under elevated pressure conditions. A maximum CO₂/CH₄ separation factor of 21.9 was reached with CO₂ permeability of 384 Barrer. Overall, MMMs exhibited enhanced gas permeabilities (up to fivefold values) without sacrificing gas selectivity compared to the corresponding pure polymeric membrane. Full article

Epilepsy is a neurological disorder that affects millions of people worldwide. Anti-epileptic drugs (AEDs) are critical for their management. However, the therapeutic window is narrow, and traditional laboratory-based therapeutic drug monitoring (TDM) methods can be time consuming and unsuitable for point-of-care testing. To address this issue, we developed a disposable sensor chip based on molecularly imprinted polymer-modified carbon paste electrodes (MIP-CPs) for the TDM of AEDs such as phenobarbital (PB), carbamazepine (CBZ), and levetiracetam (LEV). In this work, functional monomers (methacrylic acid) and crosslinking monomers (methylene bisacrylamide and ethylene glycol dimethacrylate) were copolymerized in the presence of the AED template and grafted on the graphite particles by simple radical photopolymerization. The grafted particles were mixed with silicon oil, dissolving ferrocene as a redox marker to make the MIP-carbon paste (CP). Disposable sensor chips were fabricated by packing the MIP-CP into the base made of poly (ethylene glycol terephthalate) (PET) film. The sensor’s sensitivity was determined using differential pulse voltammetry (DPV), carried out on a single sensor chip for each operation. Linearity was obtained from 0–60 μg/mL in PB and LEV and 0–12 μg/mL in CBZ, covering their respective therapeutic range. The time taken for each measurement was around 2 min. The experiment using whole bovine blood and bovine plasma indicated that the existence of species that interfered had a negligible effect on the test’s sensitivity. This disposable MIP sensor provides a promising approach for point-of-care testing and facilitating the management of epilepsy. Compared with existing tests, this sensor offers a faster and more accurate way to monitor AEDs, which is crucial for optimizing therapy and improving patient outcomes. Overall, the proposed disposable sensor chip based on MIP-CPs represents a significant advancement in AED monitoring, with the potential for rapid, accurate, and convenient point-of-care testing. Full article

Amphiphilic hydrogels from mixtures of 2-hydroxyethyl methacrylate and 2-(diethylamino)ethyl methacrylate p(HEMA-co-DEAEMA) with specific pH sensitivity and hydrophilic/hydrophobic structures were designed and polymerized via plasma polymerization. The behavior of plasma-polymerized (pp) hydrogels containing different ratios of pH-sensitive DEAEMA segments was investigated concerning possible applications in bioanalytics. In this regard, the morphological changes, permeability, and stability of the hydrogels immersed in solutions of different pHs were studied. The physico-chemical properties of the pp hydrogel coatings were analyzed using X-ray photoelectron spectroscopy, surface free energy measurements, and atomic force microscopy. Wettability measurements showed an increased hydrophilicity of the pp hydrogels when stored in acidic buffers and a slightly hydrophobic behavior after immersion in alkaline solutions, indicating a pH-dependent behavior. Furthermore, the pp (p(HEMA-co-DEAEMA) (ppHD) hydrogels were deposited on gold electrodes and studied electrochemically to investigate the pH sensitivity of the hydrogels. The hydrogel coatings with a higher ratio of DEAEMA segments showed excellent pH responsiveness at the studied pHs (pH 4, 7, and 10), demonstrating the importance of the DEAEMA ratio in the functionality of pp hydrogel films. Due to their stability and pH-responsive properties, pp (p(HEMA-co-DEAEMA) hydrogels are conceivable candidates for functional and immobilization layers for biosensors. Full article