2-Hydroxyethyl methacrylate (HEMA): A clinical review of contact allergy and allergic contact dermatitis. Part 2. Cross- and co-sensitization, other skin reactions to HEMA, position of HEMA among (meth)acrylates, sensitivity as screening agent, presence of HEMA in commercial products and practical information on patch test procedures.

This is the second part of a literature review of the clinical aspects of contact allergy to and allergic contact dermatitis from 2-hydroxyethyl methacrylate (HEMA). Topics include cross- and co-sensitization, atypical manifestations of contact allergy, frequency of positive patch tests to HEMA compared with other (meth)acrylates, sensitivity of HEMA as a screening agent, the presence of HEMA in commercial products, and practical information on patch testing procedures. Primary sensitization to methacrylates including HEMA may result in methacrylate and acrylate cross-sensitization. There is a strong cross-allergy between HEMA, ethylene glycol dimethacrylate (EGDMA), and hydroxypropyl methacrylate; many reactions to EGDMA are cross-reactions to primary HEMA sensitization. Rare atypical manifestations of HEMA-allergy include lichen planus, lymphomatoid papulosis, systemic contact dermatitis, leukoderma after positive patch tests, and systemic side effects such as nausea, diarrhoea, malaise, and palpitations. The occurrence of respiratory disease caused by methacrylates such as asthma is not infrequent. HEMA is the most frequently patch test-positive methacrylate. It is a good screening agent for allergy to other (meth)acrylates. Patch test sensitization to HEMA 2% pet. is extremely rare. There are (some) indications that HEMA is frequently used in dental products and nail cosmetics.

Contact allergy to acrylate-containing nail cosmetics: A retrospective 8-year study.

BACKGROUND: Over the last 10 years, allergic contact dermatitis (ACD) from acrylate-containing nail cosmetics (acrylic nails, gel nails, gel nail polish) has been reported repeatedly. OBJECTIVES: To investigate the frequency and clinical features of ACD in nail cosmetics in a university hospital in Amsterdam, The Netherlands. PATIENTS AND METHODS: A retrospective study in patients diagnosed with ACD from acrylate-containing nail cosmetics at the Amsterdam University Medical Centers between January 2015 and August 2023. RESULTS: Sixty-seven patients, all women, were diagnosed with ACD from nail cosmetics, representing 1.6% of all individuals and 2.3% of all women patch tested in this period. Sixty-five of sixty-seven (97%) subjects had a positive patch test to 2-hydroxyethyl methacrylate (HEMA). Forty-nine patients (73%) were consumers and 18 (27%) were professional nail stylists. The sites most frequently affected with dermatitis were the fingers (79%), hands (40%) and the head and/or neck. Avoidance of contact with acrylate-containing products resulted in complete clearing of dermatitis in 80% of patients. CONCLUSIONS: ACD from acrylate-containing nail cosmetics is frequent in women patch tested in Amsterdam. Nearly all were identified by a positive patch test to 2-hydroxyethyl methacrylate in the (meth)acrylate series or the European baseline series.

Results of patch testing 2-hydroxyethyl methacrylate (HEMA) in the European baseline series: A 4-year retrospective study.

BACKGROUND: 2-Hydroxyethyl methacrylate (HEMA) was added to the European baseline series (EBS) in 2019. Few recent data are available on the frequency and relevance of positive reactions to this hapten. OBJECTIVES: To investigate the frequency and relevance of positive patch tests to HEMA in the EBS in a university hospital in Amsterdam, The Netherlands. PATIENTS AND METHODS: Retrospective study in patients with positive patch tests to HEMA investigated between June 2019 and August 2023. RESULTS: Of 2927 consecutive patients, 88 (79 women and 9 men; 3.0%) had a positive reaction to HEMA. The prevalence in women was 3.9%, in men 1.0%. Forty-three (49%) reactions were judged to be of current clinical relevance and 21 (24%) of past relevance. In this group of 64 patients with relevant reactions, 18 (28%) had occupational contact with (meth)acrylate-containing products, of who 11 (61%) were nail stylists. In 46 patients with non-occupational allergic contact dermatitis, 31 (67%) had allergic reactions to nail cosmetics. Glues and glue-containing products accounted for 22% of the materials causing allergic contact dermatitis and dental products for 8%. CONCLUSIONS: Allergic reactions to HEMA are very frequent in women investigated in Amsterdam. Nearly two thirds of cases were caused by nail cosmetics.

2-Hydroxyethyl methacrylate (2-HEMA) sensitization, a global epidemic at its peak in Spain?

BACKGROUND: A global epidemic of allergic contact dermatitis to (meth)acrylates has been described in relation to the widespread use of manicure products. OBJECTIVES: To evaluate the frequency of sensitization to 2-hydroxyethyl methacrylate (2-HEMA) among consecutively patch tested patients with eczema in Spain; the percentage of current relevance; the MOAHLFA index; and, the potential sources of exposure to (meth)acrylates. METHODS: From January 2019 to December 2022, 2-HEMA 2% pet. was prospectively patch tested in 24 REIDAC (Spanish Allergic Contact Dermatitis Registry) centres. RESULTS: Six thousand one hundred thirty-four patients were consecutively patch tested with 2-HEMA 2% pet. 265/6134 (4.3%) were positive. Positive reactions of current relevance were identified to involve 184/265 (69%). The efficiency (number of patch tests needed to detect relevant positive patch test reactions) was 34 (6134/184). The variable 'occupational' was found to be significantly associated with a higher risk for relevant positive reactions to 2-HEMA (OR: 10.9; 95% CI: 8.1-14.9). CONCLUSION: (Meth)acrylate sensitization is a prevalent health issue in Spain. 2-HEMA 2% pet. has been identified to be a highly effective (meth)acrylate allergy marker in the GEIDAC baseline series. The responsible authorities should implement policies guaranteeing accurate labelling of industrial, medical, and consumer materials while ensuring the enforcement of said labelling through appropriate legal means.

Frequency and clinical relevance of contact allergy in dental patients.

BACKGROUND: While many studies have reported on occupational allergic contact dermatitis amongst dental personnel, studies on the relevance of patch testing in dental patients are scarce. OBJECTIVES: To determine the frequency and clinical relevance of contact allergy in patients with intra- and perioral complaints. METHODS: A total of 360 patients with intra- and perioral complaints suspected of having a contact allergy were patch-tested with the dental allergen series, European Baseline Series, and extended Amsterdam Baseline Series at Amsterdam University Medical Centers between January 2015 and November 2021. RESULTS: A total of 285 patients (79.2%) had a positive patch test reaction for either one (18.6%) or multiple allergens (60.6%). Sodium tetrachloropalladate was the most sensitising allergen with 98 patients (27.2%) testing positive, followed by nickel sulphate (23.3%), methylisothiazolinone (15.6%), and fragrance mix I (14.2%). Clinical relevance was found in 68 of 208 patients (32.7%), with patients having one (15.4%) or multiple (17.3%) patch test reactions clinically relevant to their (peri)oral complaints. CONCLUSIONS: Clinically relevant patch test reactions were frequently seen in dental patients. Although this study provides us with a better understanding on the frequency and clinical relevance of contact allergy in dental patients, further studies are needed to confirm our results.

Effect of replacing Bis-GMA with a biobased trimethacrylate on the physicochemical and mechanical properties of experimental resin composites.

OBJECTIVES: To analyze the incorporation of cardanol trimethacrylate monomer (CTMA), derived from the cashew nut shell liquid, as a substitute for Bis-GMA in acrylic resins formulations and its effect on experimental resin composites' physicochemical and mechanical properties. MATERIALS AND METHODS: The intermediary cardanol epoxy was synthesized via cardanol epoxidation, followed by the synthesis of CTMA through methacrylic anhydride solvent-free esterification. Experimental resin composites were formulated with an organic matrix composed of Bis-GMA/TEGDMA (50/50 wt %) (control). CTMA was gradually added to replace different proportions of Bis-GMA: 10 wt % (CTMA-10), 20 wt % (CTMA-20), 40 wt % (CTMA-40), and 50 wt % (CTMA-50). The composites were characterized by degree of conversion, water sorption and solubility, viscosity, thermogravimetric analysis, dynamic mechanical analysis, flexural strength and elastic modulus. Data were analyzed with one-way ANOVA and Tukey's post-hoc test (α = 0.05), except for water sorption data, which were analyzed by Kruskall-Wallis and Dunn's method. RESULTS: CTMA-based and control composites did not show statistically significant differences regarding degree of conversion, flexural strength and elastic modulus. CTMA reduced the viscosity and solubility compared to the Bis-GMA-based composite. The CTMA-40 and CTMA-50 exhibited significantly lower water sorption compared to the control. Also, acceptable thermal stability and viscoelastic properties were obtained for safe use in the oral cavity. CONCLUSIONS: Incorporating CTMA into composites resulted in similar chemical and mechanical properties compared to Bis-GMA-based material while reducing viscosity, water sorption and solubility. CLINICAL RELEVANCE: CTMA could be used as a trimethacrylate monomer replacing Bis-GMA in resin composites, thereby minimizing BPA exposure.

2-Hydroxyethyl methacrylate (HEMA): A clinical review of contact allergy and allergic contact dermatitis-Part 1. Introduction, epidemiology, case series and case reports.

2-Hydroxyethyl methacrylate (HEMA) has been increasingly recognised as a contact allergen and was added to the European baseline series in 2019. In this article (2 parts), the results of an extensive literature review of the clinical aspects of contact allergy/allergic contact dermatitis to HEMA are presented. In part 1, the epidemiology of HEMA contact allergy is discussed and detailed information on published case series and case reports presented. HEMA is an important cause of contact allergy/allergic contact dermatitis in North America and Europe with recent prevalences of >3% in the USA + Canada and 1.5%-3.7% in Europe. Currently, most cases are caused by nail cosmetics, both in consumers and professional nail stylists. In our literature review, we have found 24 studies presenting case series of patients with allergic contact dermatitis attributed to HEMA and 168 case reports. However, the presence of HEMA in the products causing ACD was established in only a minority. Part 2 will discuss cross- and co-sensitisation, and other skin reactions to HEMA, will assess whether HEMA is the most frequent (meth)acrylate allergen and how sensitive HEMA as a screening agent is, investigate the presence of HEMA in commercial products and provide practical information on patch testing procedures.

Macromolecular Design and Engineering of New Amphiphilic N-Vinylpyrrolidone Terpolymers for Biomedical Applications.

New amphiphilic VP-(di)methacrylate terpolymers of different monomer compositions and topologies have been synthesized by radical polymerization in toluene without any growth regulator of polymer chains. Their structures and properties in solid state and water solution were studied by double-detector size-exclusion chromatography; IR-, 1H, and 13C NMR-spectroscopy; DLS, TEM, TG, and DSC methods. The composition of the VP-AlkMA-TEGDM monomer mixture has been established to regulate the topology of the resulting macromolecules. The studied terpolymers presented on TEM images as individual low-contrast particles and their conglomerates of various sizes with highly ordered regions; in general, they are amorphous structures. None of the terpolymers demonstrated cytotoxic effects for noncancerous Vero and tumor HeLa cells. Hydrophobic D-α-tocopherol (TP) was encapsulated in terpolymer nanoparticles (NPs), and its antioxidant activity was evaluated by ABTS (radical monocation 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) or DPPH (2,2'-diphenyl-1-picrylhydrazyl) methods. The reaction efficiency depends on the TP-NP type. The IC50 values for the decolorization reaction of ABTS•+ and DPPH inhibition in the presence of initial and encapsulated TP were obtained.

Per- and Polyfluoroalkyl Substances in North American School Uniforms.

We analyzed 72 children's textile products marketed as stain-resistant from US and Canadian stores, particularly school uniforms, to assess if clothing represents a significant route of exposure to per- and polyfluoroalkyl substances (PFAS). Products were first screened for total fluorine (total F) using particle-induced γ-ray emission (PIGE) spectroscopy (n = 72), followed by targeted analysis of 49 neutral and ionic PFAS (n = 57). PFAS were detected in all products from both markets, with the most abundant compound being 6:2 fluorotelomer alcohol (6:2 FTOH). Total targeted PFAS concentrations for all products collected from both countries ranged from 0.250 to 153 000 ng/g with a median of 117 ng/g (0.0281-38 100 µg/m2, median: 24.0 µg/m2). Total targeted PFAS levels in school uniforms were significantly higher than in other items such as bibs, hats, stroller covers, and swimsuits, but comparable to outdoor wear. Higher total targeted PFAS concentrations were found in school uniforms made of 100% cotton than synthetic blends. Perfluoroalkyl acids (PFAAs) precursors were abundant in school uniforms based on the results of hydrolysis and total oxidizable precursor assay. The estimated median potential children's exposure to PFAS via dermal exposure through school uniforms was 1.03 ng/kg bw/day. Substance flow analysis estimated that ∼3 tonnes/year (ranging from 0.05 to 33 tonnes/year) of PFAS are used in US children's uniforms, mostly of polymeric PFAS but with ∼0.1 tonne/year of mobile, nonpolymeric PFAS.

Synthesis of Hybrid Epoxy Methacrylate Resin Based on Diglycidyl Ethers and Coatings Preparation via Cationic and Free-Radical Photopolymerization.

A series of difunctional epoxy methacrylate resins (EAs) containing at least one epoxy and at least one methacrylate group were synthesized by means of an addition reaction between epoxy-terminated diglycidyl ethers and methacrylic acid. In order to investigate the impact of polymer architecture on the course of addition reactions and further coating properties, several different types of diglycidyl ethers, i.e., linear, containing aliphatic or aromatic rings, with a short or polymeric backbone, were employed in the synthesis. The carboxyl-epoxide addition esterification reactions have been found to, in a relatively straightforward manner, control the extent of acrylation depending on the substrate feed ratio and reaction time. The structure of obtained pre-polymers was evaluated by FT-IR and NMR methods. At the same time, the extent of addition reactions was validated via quantitative analysis, including non-volatile matter content (NV), acid value (PAVs), and epoxy equivalent value (EE) analysis. The modification was carried out in a manner likely to create a compound with one epoxy and one carbon-carbon pendant group. Hence, due to the presence of both functionalities, it is possible to crosslink compositions based on synthesized EAs via two distinct mechanisms: (i) cationic polymerization or (ii) free-radical polymerization. Synthesized epoxy methacrylate pre-polymers were further employed for use in formulate photocurable coating compositions by the cationic or radical process. Furthermore, the photopolymerization behavior and properties of cured coatings were explored regarding some structural factors and parameters. The investigated polymeric materials cure in a short time to obtain coatings with good properties, which is why they can be successfully used to produce protective and decorative coatings for many industries.

A New Protocol for Ash Wood Modification: Synthesis of Hydrophobic and Antibacterial Brushes from the Wood Surface.

The article presents the modification of ash wood via surface initiated activators regenerated by electron transfer atom transfer radical polymerization mediated by elemental silver (Ag0 SI-ARGET ATRP) at a diminished catalyst concentration. Ash wood is functionalized with poly(methyl methacrylate) (PMMA) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) to yield wood grafted with PMMA-b-PDMAEMA-Br copolymers with hydrophobic and antibacterial properties. Fourier transform infrared (FT-IR) spectroscopy confirmed the covalent incorporation of functional ATRP initiation sites and polymer chains into the wood structure. The polymerization kinetics was followed by the analysis of the polymer grown in solution from the sacrificial initiator by proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The polymer layer covalently attached to the wood surface was observed by scanning electron microscopy (SEM). The hydrophobic properties of hybrid materials were confirmed by water contact angle measurements. Water and sodium chloride salt aqueous solution uptake tests confirmed a significant improvement in resistance to the absorption of wood samples after modification with polymers. Antibacterial tests revealed that wood-QPDMAEMA-Br, as well as wood-PMMA-b-QPDMAEMA-Br, exhibited higher antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) in comparison with Gram-negative bacteria (Escherichia coli). The paper presents an economic concept with ecological aspects of improving wood properties, which gives great opportunities to use the proposed approach in the production of functional hybrid materials for industry and high quality sports equipment, and in furniture production.

[Allergic reactions to bioimplants]. / Allergische Reaktionen auf Bioimplantate.

BACKGROUND: Bioimplants are used in a variety of ways in otorhinolaryngology, most commonly in facial reconstructive surgery, cochlear implants (CI), bone-anchored hearing aids, and partial/total ossicular replacement prostheses (PORP/TORP), but also for tympanic drainage, laryngeal cannula, voice prostheses after laryngectomy, etc., and in otorhinolaryngology-related procedures as dental implants in dentistry. METHODS: A literature search was performed to analyze the immunology of allergic reactions to bioimplants and to determine the available evidence by searching Medline, PubMed, and national and international study and guideline registries and the Cochrane Library. Human studies published in the period up to and including 12/2021 were considered. RESULTS: Based on the international literature and previous experience, a review of allergies to bioimplants in otolaryngology is presented. CONCLUSION: Otorhinolaryngologists should always consider the possibility of allergic reactions when inserting allogeneic materials, particularly, but not only, when using bioimplants.

Production and Polymerization of Biobased Acrylates and Analogs.

To prepare biobased polymers, particular attention must be paid to the obtention of the monomers from which they are derived. (Meth)acrylates and their analogs constitute such a class of monomers that have been extensively studied due to the wide range of polymers accessible from them. This review therefore aims to highlight the progresses made in the production and polymerization of (meth)acrylates and their analogs. Acrylic acid production from biomass is close to commercialization, as three different high-potential intermediates are identified: glycerol, lactic acid, and 3-hydroxypropionic acid. Biobased methacrylic acid is less common, but several promising options are available, such as the decarboxylation of itaconic acid or the dehydration of 2-hydroxyisobutyric acid. Itaconic acid is also a vinylic monomer of great interest, and polymers derived from it have already found commercial applications. Methylene butyrolactones are promising monomers, obtained from bioresources via three different intermediates: levulinic, succinic, or itaconic acid. Although expensive, methylene butyrolactones have a strong potential for the production of high-performance polymers. Finally, ß-substituted acrylic monomers, such as cinnamic, fumaric, muconic, or crotonic acid, are also examined, as they provide an original access to biobased materials from various renewable raw materials, such as protein waste, lignin, or wastewater.

The activity of methacrylate esters in skin sensitisation test methods II. A review of complementary and additional analyses.

Allergic contact dermatitis is an important occupational health issue, and there is a need to identify accurately those chemicals that have the potential to induce skin sensitisation. Hazard identification was performed initially using animal (guinea pig and mouse) models. More recently, as a result of the drive towards non-animal methods, alternative in vitro and in silico approaches have been developed. Some of these new in vitro methods have been formally validated and have been assigned OECD Test Guideline status. The performance of some of these recently developed in vitro methods, and of 2 quantitative structure-activity relationships (QSAR) approaches, with a series of methacrylate esters has been reviewed and reported previously. In this article that first review has been extended further with additional data and complementary analyses. Results obtained using in vitro methods (Direct Peptide Reactivity Assay, DPRA; ARE-Nrf2 luciferase test methods, KeratinoSens and LuSens; Epidermal Sensitisation Assay, EpiSensA; human Cell Line Activation Test, h-CLAT, and the myeloid U937 Skin Sensitisation test, U-SENS), and 2 QSAR approaches (DEREK™-nexus and TIMES-SS), with 11 methacrylate esters and methacrylic acid are reported here, and compared with existing data from the guinea pig maximisation test and the local lymph node assay. With this series of chemicals it was found that some in vitro tests (DPRA and ARE-Nrf2 luciferase) performed well in comparison with animal test results and available human skin sensitisation data. Other in vitro tests (EpiSensA and h-CLAT) proved rather more problematic. Results with DEREK™-nexus and TIMES-SS failed to reflect accurately the skin sensitisation potential of the methacrylate esters. The implications for assessment of skin sensitising activity are discussed.

Genotoxic and cytotoxic potential of methacrylate-based orthodontic adhesives.

OBJECTIVES: The biocompatibility of methacrylate-based adhesives is a topic that is intensively discussed in dentistry. Since only limited evidence concerning the cyto- and genotoxicity of orthodontic adhesives is available, the aim of this study was to measure the genotoxic potential of seven orthodontic methacrylate-based adhesives. MATERIALS AND METHODS: The XTT assay was utilized to determine the cytotoxicity of Assure Plus, Assure Bonding Resin, ExciTE F, OptiBond Solo Plus, Scotchbond Universal Adhesive, Transbond MIP, and Transbond XT after an incubation period of 24 h on human gingival fibroblasts. We also performed the γH2AX assay to explore the genotoxic potential of the adhesives within cytotoxic dose ranges after an incubation period of 6 h. RESULTS: The XTT assay showed a concentration-dependent reduction in cell viability. The decrease in cellular viability was in the same dose range most significant for Assure Plus, rendering it the adhesive material with the highest cytotoxicity. Employing the γH2AX assay, a concentration-dependent increase in H2AX phosphorylation was detected, indicating induction of DNA damage. CONCLUSIONS: For most products, a linear correlation between the material concentration and γH2AX foci was observed. The most severe effect on γH2AX focus induction was found for Transbond MIP, which was the only adhesive in the test group containing the co-initiator diphenyliodonium hexafluorophosphate (DPIHP). CLINICAL RELEVANCE: The data indicate that orthodontic adhesives, notably Transbond MIP, bear a genotoxic potential. Since the study was performed with in vitro cultivated cells, a direct translation of the findings to in vivo exposure conditions should be considered with great diligence.

Synthesis of Epoxy Methacrylate Resin and Coatings Preparation by Cationic and Radical Photocrosslinking.

This work involves the synthesis of hybrid oligomers based on the epoxy methacrylate resin. The EA resin was obtained by the modification of industrial-grade bisphenol A-based epoxy resin and methacrylic acid has been synthesized in order to develop multifunctional resins comprising both epoxide group and reactive, terminal unsaturation. Owing to the presence of both epoxy and double carbon-carbon pendant groups, the reaction product exhibits photocrosslinking via two distinct mechanisms: (i) cationic ring-opening polymerization and (ii) free radical polymerization. Monitoring of EA synthesis reactions over time using PAVs, MAAC and NV parameters, and the FT-IR method reveals that esterification reactions proceed faster at the start, exhibiting over 40% of conversion within the initial 60 min, which can be associated with a relatively high concentration of reactive sites and low viscosity of the reaction mixture at the initial reaction stage. With the further increase in the reaction time, the reaction rate tends to decrease. The control of the EA synthesis process can guide how to adjust reactions to obtain EAs with desired characteristics. Based on obtained values, one can state that the optimum synthesis time of about 4-5 h should be adopted to prepare EAs having both epoxy groups and unsaturated double bonds. The structure of the obtained EA was confirmed by FT-IR and NMR methods, as well as the determination of partial acid value and epoxy equivalent. Samples at various stages of synthesis were cured with UV radiation in order to study the kinetics of the process according to cationic and radical polymerization determined via photo-differential scanning calorimetry (photo-DSC) and real-time infrared spectroscopy (RT-IR) and then the properties of the cured coatings were tested. It turned out that the cationic polymerization was slower with a lower conversion of the photoreactive groups, as compared to the radical polymerization. All the obtained EA coatings were characterized by good properties of cured coatings and can be successfully used in the coating-forming sector.

Controlled (Co)Polymerization of Methacrylates Using a Novel Symmetrical Trithiocarbonate RAFT Agent Bearing Diphenylmethyl Groups.

Herein, we report a novel type of symmetrical trithiocarbonate chain transfer agent (CTA) based diphenylmethyl as R groups. The utilization of this CTA in the Reversible Addition-Fragmentation chain Transfer (RAFT) process reveals an efficient control in the polymerization of methacrylic monomers and the preparation of block copolymers. The latter are obtained by the (co)polymerization of styrene or butyl acrylate using a functionalized macro-CTA polymethyl methacrylate (PMMA) previously synthesized. Data show low molecular weight dispersity values (D < 1.5) particularly in the polymerization of methacrylic monomers. Considering a typical RAFT mechanism, the leaving groups (R) from the fragmentation of CTA should be able to re-initiate the polymerization (formation of growth chains) allowing an efficient control of the process. Nevertheless, in the case of the polymerization of MMA in the presence of this symmetrical CTA, the polymerization process displays an atypical behavior that requires high [initiator]/[CTA] molar ratios for accessing predictable molecular weights without affecting the D. Some evidence suggests that this does not completely behave as a common RAFT agent as it is not completely consumed during the polymerization reaction, and it needs atypical high molar ratios [initiator]/[CTA] to be closer to the predicted molecular weight without affecting the D. This work demonstrates that MMA and other methacrylic monomers can be polymerized in a controlled way, and with "living" characteristics, using certain symmetrical trithiocarbonates.

Multicatalytic Transformation of (Meth)acrylic Acids: a One-Pot Approach to Biobased Poly(meth)acrylates.

Shifting from petrochemical feedstocks to renewable resources can address some of the environmental issues associated with petrochemical extraction and make plastics production sustainable. Therefore, there is a growing interest in selective methods for transforming abundant renewable feedstocks into monomers suitable for polymer production. Reported herein are one-pot catalytic systems, that are active, productive, and selective under mild conditions for the synthesis of copolymers from renewable materials. Each system allows for anhydride formation, alcohol acylation and/or acid esterification, as well as polymerization of the formed (meth)acrylates, providing direct access to a new library of unique poly(meth)acrylates.

Physico-chemical and antimicrobial properties and the shelf life of experimental endodontic sealers containing metal methacrylates.

The objective of this study was to evaluate the physico-chemical and antimicrobial properties of a dual polymerization experimental endodontic sealer (E) and experimental sealers containing dibutyltin methacrylate (Sn2+) (ETs) or calcium methacrylate (Ca2+) (ECs). The pH and ion release levels of the sealers were measured. The dimensional stability was evaluated in accordance with ISO 6876. Biofilm growth inhibition was evaluated using confocal laser scanning microscopy (CLSM). Biofilm viability analysis was performed using the SYTO 9 technique. The shelf life was evaluated through the degree of conversion and film thickness tests after the sealers had been stored for different periods of time. For statistical analysis, ANOVA and Tukey's post hoc test were used, with a significance level of 5%. ETs revealed better anti-biofilm potential after 15 days than that of the controls. The degree of conversion was reduced after the shelf-life period. The addition of calcium and dibutyltin methacrylate improved the anti-biofilm properties of the experimental endodontic sealer without impairing their physico-chemical properties.

Smart Delivery Systems Based on Poly(glycidyl methacrylate)s-Coated Organic/Inorganic Core-Shell Nanohybrids.

Smart delivery systems have gained momentum over the last few decades due to their potential to realize enhanced therapeutic efficacy. Poly(glycidyl methacrylate)s (PGMAs), which spring up like mushrooms, have drawn great attention in the theranostics field, especially in multifunctional theranostic systems. The marriage of PGMAs with functional inorganic cores is expected to integrate diagnosis (e.g., fluorescence, X-ray computed tomography, magnetic resonance, photoacoustic and upconversion luminescence imaging), treatment, or multimodal synergistic therapies (e.g., chemotherapy, gene therapy, photothermal therapy) in one pot for personalized medicine. In this review, recent progress in various PGMA-coated nanohybrids based on the type of integrated inorganic nanoparticle, including silica nanoparticles, magnetic nanoparticles, quantum dots, gold nanoparticles, gold nanorods, metal-organic frameworks, cellulose nanocrystals, and their core-shell nanostructures is systematically reviewed. Future work in this field is anticipated to be devoted to developing efficient real-time-imaging-guided multimodal synergistic therapies.