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Nature Communications Nov 2022Biological ion channels rely on ions as charge carriers and unidirectional ion flow to produce and transmit signals. To realize artificial biological inspired circuitry...
Biological ion channels rely on ions as charge carriers and unidirectional ion flow to produce and transmit signals. To realize artificial biological inspired circuitry and seamless human-machine communication, ion-transport-based rectification devices should be developed. In this research, poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) gel polymer electrolytes (GPEs) are assembled to construct a novel ionic diode, enabling ion rectification through ion-diffusion/migration that emulates biological systems. This ion rectification results from the different diffusion/migration behaviors of mobile ions transporting in the GPE heterojunction. The electrical tests of the GPE heterojunction reveal outstanding rectifying ratio of 23.11. The GPE ionic diode operates in wide temperature window, from -20 °C (anti-freezing) to 125 °C (thermal tolerance). The absence of redox reactions is verified in the cyclic voltammogram. The GPE ionic diodes are used to construct ionic logic gates for signal communication. Furthermore, rectification of a triboelectric nanogenerator and potential for synaptic devices are demonstrated.
Topics: Humans; Polymers; Electrolytes; Ions; Polymethyl Methacrylate; Ion Transport
PubMed: 36335134
DOI: 10.1038/s41467-022-34429-9 -
International Journal of Molecular... Mar 2020Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity...
Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity and is cytotoxic. Implant loosening and toxic complications are significant and recognized problems. Here we devised two strategies to improve PMMA-based bone cement: (1) adding 4-methacryloyloxylethyl trimellitate anhydride (4-META) to MMA monomer to render it hydrophilic; and (2) using tri-n-butyl borane (TBB) as a polymerization initiator instead of benzoyl peroxide (BPO) to reduce free radical production. Rat bone marrow-derived osteoblasts were cultured on PMMA-BPO, common bone cement ingredients, and 4-META/MMA-TBB, newly formulated ingredients. After 24 h of incubation, more cells survived on 4-META/MMA-TBB than on PMMA-BPO. The mineralized area was 20-times greater on 4-META/MMA-TBB than PMMA-BPO at the later culture stage and was accompanied by upregulated osteogenic gene expression. The strength of bone-to-cement integration in rat femurs was 4- and 7-times greater for 4-META/MMA-TBB than PMMA-BPO during early- and late-stage healing, respectively. MicroCT and histomorphometric analyses revealed contact osteogenesis exclusively around 4-META/MMA-TBB, with minimal soft tissue interposition. Hydrophilicity of 4-META/MMA-TBB was sustained for 24 h, particularly under wet conditions, whereas PMMA-BPO was hydrophobic immediately after mixing and was unaffected by time or condition. Electron spin resonance (ESR) spectroscopy revealed that the free radical production for 4-META/MMA-TBB was 1/10 to 1/20 that of PMMA-BPO within 24 h, and the substantial difference persisted for at least 10 days. The compromised ability of PMMA-BPO in recruiting cells was substantially alleviated by adding free radical-scavenging amino-acid N-acetyl cysteine (NAC) into the material, whereas adding NAC did not affect the ability of 4-META/MMA-TBB. These results suggest that 4-META/MMA-TBB shows significantly reduced cytotoxicity compared to PMMA-BPO and induces osteoconductivity due to uniquely created hydrophilic and radical-free interface. Further pre-clinical and clinical validations are warranted.
Topics: Animals; Arthroplasty, Replacement, Hip; Biocompatible Materials; Bone Cements; Bone Marrow Cells; Bone Regeneration; Bone and Bones; Boranes; Boron Compounds; Calcification, Physiologic; Cell Line; Cell Survival; Free Radicals; Hydrophobic and Hydrophilic Interactions; Male; Materials Testing; Methacrylates; Methylmethacrylate; Methylmethacrylates; Osteoblasts; Osteogenesis; Phenotype; Polymerization; Polymethyl Methacrylate; Prostheses and Implants; Rats; Rats, Sprague-Dawley
PubMed: 32244335
DOI: 10.3390/ijms21072405 -
Molecules (Basel, Switzerland) May 2020In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the...
In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the filling of the imprint stamp and its subsequent detachment may impose some practical challenges. Here we explored thermal and reverse NIL patterning of polyvinylferrocene and vinylferrocene-methyl methacrylate copolymers to prepare complex non-spherical objects and patterns. While neat polyvinylferrocene was found to be unsuitable for NIL, freshly-prepared vinylferrocene-methyl methacrylate copolymers, for which identity and purity were established, have been structured into 3D-micro/nano-patterns using NIL. The cross-, square-, and circle-shaped columnar structures form a 3 × 3 mm arrangement with periodicity of 3 µm, 1 µm, 542 nm, and 506 nm. According to our findings, vinylferrocene-methyl methacrylate copolymers can be imprinted without further additives in NIL processes, which opens the way for redox-responsive 3D-nano/micro-objects and patterns via NIL to be explored in the future.
Topics: Ferrous Compounds; Methylmethacrylate; Molecular Imprinting; Nanocomposites; Polymers; Polyvinyls; Surface Properties; Vinyl Compounds
PubMed: 32456151
DOI: 10.3390/molecules25102438 -
International Journal of Molecular... May 2022Amidst growing technological advancements, newer denture base materials and polymerization methods have been introduced. During fabrication, certain mechanical... (Review)
Review
Amidst growing technological advancements, newer denture base materials and polymerization methods have been introduced. During fabrication, certain mechanical properties are vital for the clinical longevity of the denture base. This systematic review aimed to explore the effect of newer denture base materials and/or polymerization methods on the mechanical properties of the denture base. An electronic database search of English peer-reviewed published papers was conducted using related keywords from 1 January 2011, up until 31 December 2021. This systematic review was based on guidelines proposed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The search identified 579 papers. However, the inclusion criteria recognized 22 papers for eligibility. The risk of bias was moderate in all studies except in two where it was observed as low. Heat cure polymethyl methacrylate (PMMA) and compression moulding using a water bath is still a widely used base material and polymerization technique, respectively. However, chemically modified PMMA using monomers, oligomers, copolymers and cross-linking agents may have a promising result. Although chemically modified PMMA resin might enhance the mechanical properties of denture base material, no clear inferences can be drawn about the superiority of any polymerization method other than the conventional compression moulding technique.
Topics: Denture Bases; Materials Testing; Polymerization; Polymers; Polymethyl Methacrylate
PubMed: 35628546
DOI: 10.3390/ijms23105737 -
PeerJ 2023The study's objective is to assess the adherence of in different types of denture polymers and the effectiveness of eugenol and commercialized denture cleansers in the...
BACKGROUND
The study's objective is to assess the adherence of in different types of denture polymers and the effectiveness of eugenol and commercialized denture cleansers in the removal of . Three types of denture base polymers (Lucitone 199 (High-Impact PMMA), Impact (conventional PMMA) and Eclipse (UDMA)) and two hard denture reline materials (Kooliner and Tokuyama Rebase II Fast) were used in this study.
METHODS
Three hundred samples were prepared (6 × 2 mm disc shape) and divided into five groups of denture polymers ( = 60) and further subjected into five treatment groups (Polident, Steradent, distilled water, eugenol 5-minutes, and eugenol 10-min). Three samples were extracted from each treatment group for baseline data ( = 12). Baseline data were used to calculate the initial number of adherence. A 0.5 ml immersion solution from each specimen was cultured on YPD agar and incubated for 48 h at 37 °C. Visible colonies were counted using a colony counter machine (ROCKER Galaxy 230).
RESULTS
The result showed that the denture base polymer significantly affected the initial adherence ( = 0.007). The removal of was also considerably affected by the denture base polymers and denture cleansers ( < 0.05). Lucitone, Tokuyama, and Kooliner denture base polymers immersed for 3 min in eugenol showed the best results of removal.
DISCUSSION
This study's overall results showed that all denture polymers used as denture bases had an effect on initial adherence and removal from the denture base, and eugenol is comparable to commercialised denture cleansers in reducing the number of attached on denture base polymers.
Topics: Antifungal Agents; Candida albicans; Denture Cleansers; Eugenol; Polymethyl Methacrylate; Polymers; Dentures
PubMed: 37601266
DOI: 10.7717/peerj.15750 -
European Journal of Trauma and... Dec 2022High clinical success rates have been reported with the Masquelet technique in the treatment of traumatic bone loss. An increasing number of studies suggest that various... (Review)
Review
PURPOSE
High clinical success rates have been reported with the Masquelet technique in the treatment of traumatic bone loss. An increasing number of studies suggest that various factors can influence the properties of induced membranes. Goal of this systematic review is to answer the following questions: (1) which are the ideal spacer properties (material, surface topography, antibiotic supplementation) to booster the quality and osteogenic potential of induced membranes? (2) what is the ideal time to perform the second-stage operation?
METHODS
A systematic search using the keywords "((Masquelet) OR (Induced Periosteum)) AND ((Spacer) OR (Time))" was performed in PubMed, Embase and Cochrane Library according to PRISMA guidelines. Studies published up to the 23rd of February 2022 were included and assessed independently by two reviewers.
RESULTS
Thirteen animal and 1 clinical studies were identified to address the above questions. Spacer materials used were PMMA, silicone, titanium, polypropylene, PVA, PCL and calcium sulfate. With the exception of PVA sponges, all solid materials could induce membranes. Low union rates have been reported with titanium and rough surfaced spacers. Scraping of the inner surface of the IM also increased bony union rates. In terms of the ideal timing to perform the second-stage evidence suggests that membranes older than 8 weeks continue to have regenerative capacities similar to younger ones.
CONCLUSION
Membranes induced by smooth PMMA spacers loaded with low concentrations of antibiotics showed powerful osteogenic properties. Other materials such as Polypropylene or Calcium sulfate can also be used with good results. Despite current recommendation to perform the second stage operation in 4-8 weeks, membranes older than 8 weeks seem to have similar regenerative capacities to younger ones.
Topics: Animals; Polymethyl Methacrylate; Titanium; Calcium Sulfate; Polypropylenes
PubMed: 35726029
DOI: 10.1007/s00068-022-02005-x -
Medicina (Kaunas, Lithuania) Oct 2022: The treatment of proximal humerus fractures in elderly patients is challenging, with reported high complication rates mostly related to implant failure involving screw...
: The treatment of proximal humerus fractures in elderly patients is challenging, with reported high complication rates mostly related to implant failure involving screw cut-out and penetration. Metaphyseal defects are common in osteoporotic bone and weaken the osteosynthesis construct. A novel technique for augmentation with polymethylmethacrylate (PMMA) bone cement was developed for the treatment of patients in advanced age with complex proximal humerus fractures and metaphyseal voids, whereby the cement was allowed to partially cure for 5-7 min after mixing to achieve medium viscosity, and then it was manually placed into the defect through the traumatic lateral window with a volume of 4-6 mL per patient. The aim of this retrospective clinical study was to assess this technique versus autologous bone graft augmentation and no augmentation. : The outcomes of 120 patients with plated Neer three- and four-part fractures, assigned to groups of 63 cases with no augmentation, 28 with bone graft augmentation and 29 with cement augmentation, were assessed in this study. DASH, CS, pain scores and range of motion were analyzed at 3, 6 and 12 months. Statistical analysis was performed with factors for treatment and age groups, Neer fracture types and follow-up periods, and with the consideration of age as a covariate. : DASH and CS improved following cement augmentation at three and six months compared to bone grafting, being significant when correcting for age as a covariate ( ≤ 0.007). While the age group had a significant effect on both these scores with worsened values at a higher age for non-augmented and grafted patients ( ≤ 0.044), this was not the case for cement augmented patients ( ≥ 0.128). Cement augmentation demonstrated good clinical results at 12 months with a mean DASH of 10.21 and mean CS percentage of 84.83% versus the contralateral side, not being significantly different among the techniques ( ≥ 0.372), despite the cement augmented group representing the older population with more four-part fractures. There were no concerning adverse events specifically related to the novel technique. : This study has detailed a novel technique for the treatment of metaphyseal defects with PMMA cement augmentation in elderly patients with complex proximal humerus fractures and follow-up to one year, whereby the cement was allowed to partially cure to achieve medium viscosity, and then it was manually placed into the defect through the traumatic lateral window. The results demonstrate clinically equivalent short-term results to 6 months compared to augmentation with bone graft or no augmentation-despite the patient group being older and with a higher rate of more severe fracture patterns. The technique appears to be safe with no specifically related adverse events and can be added in the surgeon's armamentarium for the treatment of these difficult to manage fractures.
Topics: Humans; Aged; Bone Cements; Polymethyl Methacrylate; Retrospective Studies; Shoulder Fractures; Bone Plates; Fracture Fixation, Internal; Humerus
PubMed: 36295586
DOI: 10.3390/medicina58101424 -
F1000Research 2021Bruxism is increasingly common in today's stressful world and affects mainly young patients. It is a combined disease that involves dentition and its supporting...
Bruxism is increasingly common in today's stressful world and affects mainly young patients. It is a combined disease that involves dentition and its supporting structures, muscles, ligaments and the temporomandibular joint (TMJ). Here we present a complete combined analog and digital clinical protocol in a patient with parafunction. A young patient sought help due to impaired aesthetics, as a result of abraded tooth surfaces and severe symptoms of TMJ. We implemented a therapeutic protocol of six stages: deprogramming of the muscles and determination of treatment position and digital optimization; realization of the morphological plan for the upper dentition; non-invasive repositioning of the lower jaw by splint therapy; splint placement and follow-up; morphological planning of the lower dentition and replacement of the splint with fixed prosthesis with follow-up; and completion of the case with ceramic restorations. The digitally modeled temporary constructions for the upper jaw were made of PMMA and placed in the patient's mouth together with the splint on the lower jaw, made of Ceramill Splintec. After an adaptation period, all restorations were replaced by permanent zirconia. We achieved restoration of the defects of the dental arches and hard dental tissues and recovery to normal height of the lower third of the face (vertical dimension occlusion), fixed a stable and balanced position of the lower jaw, and repaired the normal physiological position of the TMJ for the patient. Аfter a multi-stage treatment we received a result satisfying the patient, the dentist and the dental technician. Aesthetics and function were restored, and clinical symptoms were removed from the TMJ.
Topics: Bruxism; Humans; Polymethyl Methacrylate; Workflow
PubMed: 36111070
DOI: 10.12688/f1000research.72961.2 -
Head & Face Medicine Aug 2023The aim of this study was to establish a sheep model of the Puricelli biconvex arthroplasty (ABiP) technique in sheep for evaluating its functional, biological and...
BACKGROUND
The aim of this study was to establish a sheep model of the Puricelli biconvex arthroplasty (ABiP) technique in sheep for evaluating its functional, biological and histological parameters.
METHODS
Ten Corriedale black sheep were submitted to TMJ total reconstruction with poly(methyl methacrylate) (PMMA) using ABiP and euthanized after 45 (n = 5) or 90 (n = 5) days. Control animals (n = 2) underwent sham operations and were euthanized after 45 days. Variables were assessed before the surgery (T0), immediately after (T1) and at 45 or 90 postoperative days (T2).
RESULTS
Histological analyses showed regression of inflammatory cells over the follow-up period. PMMA showed reduced porosity and roughness in the articular contact area. PMMA temporal components showed linear and volumetric wear in comparison to control, but no foreign body reaction was observed. The reconstructions were stable in all animals. The amplitude of mouth opening and left lateral movements were maintained, except for a reduction in the range of right lateral movements at day 90 in the experimental group. Clinical, macroscopic and radiographic observations showed that the reconstructions were stable.
CONCLUSIONS
The analysis of functional, biological and histological parameters in sheep submitted to ABiP showed stable results of the procedure, with maintenance of body weight and all mandibular movements, save contralateral mandibular movement, suggesting that joint function was completely maintained following the procedure. This experimental study provides support for clinical results previously reported of the ABiP technique in TMJ reconstruction procedures.
Topics: Animals; Temporomandibular Joint Disorders; Polymethyl Methacrylate; Tooth Ankylosis; Arthroplasty; Mandible; Temporomandibular Joint; Range of Motion, Articular; Mandibular Condyle
PubMed: 37528466
DOI: 10.1186/s13005-023-00379-w -
Blood Purification 2023High-flux hemodialysis membranes may modulate the cytokine storm of SARS-CoV-2, but their impact on chronic hemodialysis (CHD) patients is unknown. The aim of the study... (Observational Study)
Observational Study
INTRODUCTION
High-flux hemodialysis membranes may modulate the cytokine storm of SARS-CoV-2, but their impact on chronic hemodialysis (CHD) patients is unknown. The aim of the study was the evaluation of asymmetric cellulose triacetate (ATA) and polymethylmethacrylate (PMMA) dialyzers on inflammatory markers and clinical outcomes in CHD patients with SARS-CoV-2.
METHODS
A prospective, observational study on CHD patients with SARS-CoV-2 was carried out. Patients were enrolled from March 2020 to May 2021. Pre- and postdialysis C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) were determined at each session. Patients who underwent on-line hemodiafiltration (OLHDF) with a PMMA dialyzer were compared with those treated with OLHDF with a ATA dialyzer. The primary endpoint was the differences in the reduction ratio per session (RR) of CRP, PCT, IL-6, and IL-6 RR >25%.
RESULTS
We consecutively enrolled 74 CHD patients with COVID-19, 48 were treated with ATA membrane, and 26 with PMMA. Median IL-6 RR was higher in the ATA group compared to PMMA (17.08%, IQR -9.0 to 40.0 vs. 2.95%, IQR -34.63 to 27.32). Median CRP RR was 7.77% (IQR 2.47-13.77) in the ATA group versus 4.8% (IQR -2.65 to 11.38) in the PMMA group (p = 0.0017). Median PCT-RR% was 77.38% (IQR 70.92-82.97) in ATA group versus 54.59% (IQR 42.62-63.16) in the PMMA group (p < 0.0001). A multiple logistic regression analysis with IL-6 RR >25% as the outcome including the membrane employed, pre-dialysis IL-6, CRP, PCT, and ferritin showed that ATA led to a higher probability to reach the outcome (OR 1.891, 95% CI 1.273-2.840, p = 0.0018) while higher CRP favors the risk of lower IL-6 RR values (OR 0.910, 95% CI 0.868-0.949, p ≤ 0.0001).
CONCLUSIONS
In SARS-CoV-2 CHD patients treated with OLHDF, ATA showed a better anti-inflammatory profile, regarding IL-6 RR, compared to PMMA.
Topics: Humans; Polymethyl Methacrylate; SARS-CoV-2; Prospective Studies; Dialysis; Interleukin-6; COVID-19; Renal Dialysis; C-Reactive Protein; Anti-Inflammatory Agents; Membranes, Artificial
PubMed: 36323242
DOI: 10.1159/000526319