Hydrophilic modification of PVDF-based SERS imprinted membrane for the selective detection of L-tyrosine.

The polyvinylidene difluoride (PVDF) membrane has received considerable attention as a flexible surface enhanced Raman scattering (SERS) substrate due to its excellent mechanical and physicochemical properties. However, the poor fouling resistance of PVDF membrane due to its intrinsic hydrophobic property limits its practical application. To address this, in this investigation, a SERS imprinted membrane is synthesized based on W18O49/Ag composites. Firstly, to promote hydrophilicity, N-vinyl-2-pyrrolidone (NVP) and triethoxyvinylsilane (VTES) are copolymerized by hydrolysis condensation and linked with engineered polyvinypyrrolidone (PVP) chains exposed on the surface of membrane. Furthermore, W18O49/Ag composites are dispersed on the membrane under the assistance of polydopamine (pDA) to promote the pollution resistance. Subsequently, in order to demonstrate the practical detection property, W18O49/Ag/PVDF membrane is selected as the SERS substrate to synthesize SERS imprinted membrane by precipitation polymerization for the selective detection of L-tyrosine. The characteristic results reveal that the SERS-imprinted membrane exhibits satisfactory hydrophilicity, and it can effectively degrade the pollutant molecules absorbed on its surface under ultraviolet light illumination. It is proved from the detection results that the LOD of WADP-MIMs for L-tyrosine reached 10-9 mol L-1 when the concentration of L-tyrosine changed between 10-3-10-9 mol L-1. The correlation coefficient (R2) is 0.994 and the limit of detection is 10-9 mol L-1. Meanwhile, it can be applied for the selective detection of L-tyrosine in mixture samples. Overall, this study presents a novel approach for the hydrophilic modification and pollution resistance enhancement of PVDF-based SERS imprinted membrane, which can be effectively utilized for the selective detection of practical samples.

Molecularly imprinted polymers combined with membrane-protected solid-phase extraction to detect triazines in tea samples.

Spherical molecularly imprinted polymers (MIPs) were prepared by emulsion polymerization. The isothermal adsorption and selective adsorption indicated that the MIPs obtained exhibit excellent specific recognition for the template (atrazine) and its analogues. The MIPs were encapsulated in a polypropylene microporous membrane to fabricate MIP adsorption packages for the direct extraction of triazines in uncentrifuged and unfiltered tea extracts. The extraction conditions affecting the extraction efficiency, including the type and volume of extraction solvent, the number of MIP adsorption packages, the surface area of the MIP adsorption packages, the mass of MIPs in the MIP adsorption packages, the extraction time, the eluting solvent, and the eluting volume, were optimized. Under the optimal extraction and high-performance liquid chromatography-tandem mass spectrometry conditions, the method exhibited excellent linearity in the range from 0.5 to 250 ng g-1, with R2 ≥ 0.9992. The detection limit of the method was 0.09-0.18 ng g-1. The intraday and interday relative standard deviations ranged from 3.1% to 7.5% and from 3.1% to 7.9%, respectively. The method was successfully used to detect triazines in five tea samples. At a spiking concentration of 2 ng g-1, satisfactory recoveries ranging from (81 ± 3)% to (104 ± 7)% were obtained. The membrane-protected solid-phase extraction method based on molecularly imprinted material is expected to be widely used to enrich triazines in complex samples. Graphical Abstract Schematic illustration of the MIPs combined with membrane-protected solid-phase extraction of triazines in tea sample.

The chemical and optical stability evaluation of injectable restorative materials under wet challenge.

OBJECTIVES: To investigate and compare the chemical and optical stability of four restorative composite materials: two injectable resins, one flowable resin and one compomer. METHODS: Two injectable nano-filled composite resins: G-aenial Universal (GU) and Beautifil Injectable XSL (BI), a flowable composite resin: Filtek Supreme Flowable (FS) and a compomer: Dyract Flow (DF), in A2 shade were tested and compared. Water sorption and solubility were conducted according to ISO4049:2019 standard; ICP-OES and F-ion selective electrode were used to test the elemental release; Degree of conversion (DC) was obtained by using FTIR; water contact angle was obtained by static sessile drop method, and a spectrophotometer was used for optical properties (ΔE⁎, ΔL⁎ and TP). SPSS 28.0 was used for statistical analysis and the significant level was pre-set as α = 0.05. RESULTS: GU performed the best in water sorption and solubility, FS had the lowest elemental release, the best colour stability, and the highest DCIM and DC24-h. DF, the compomer had the lowest, and GU and BI, the injectable composites had the largest water contact angle, respectively. Correlations were found between water sorption and water solubility. CONCLUSIONS: The four composite restorative materials showed different chemical and optical behaviours. Overall, composite resins performed better than compomer, while additional laboratory and in vivo tests are necessary to obtain a more comprehensive comparison between injectable and flowable composite resins. Wsp and Wsl are influenced by many common factors, and the values are highly positively related. CLINICAL SIGNIFICANCE: A comprehensive understanding of materials is crucial before selecting materials for clinical practice. Composite resins rather than compomers are recommended because of their exceptional properties, which make them eligible for a wide range of clinical applications and an elongated lifespan.

The mechanical, wear, antibacterial properties and biocompatibility of injectable restorative materials under wet challenge.

OBJECTIVES: To evaluate the mechanical, wear, antibacterial properties, and biocompatibility of injectable composite materials. METHODS: Two injectable composite resins (GU and BI), one flowable composite resin (FS), and one flowable compomer (DF), in A2 shade, were tested. Mechanical properties were tested via three-point bending test immediately after preparation and after 1-day, 7-day, 14-day, and 30-day water storage. Under water-PMMA slurry immersion, specimens were subjected to a 3-body wear test (10,000 cycles) against stainless steel balls, while the roughness, wear depth, and volume loss were recorded. After 1-day and 3-day MC3T3-E1 cell culture, cell viability was evaluated with CCK-8 test kits, while the cell morphology was observed under CLSM and SEM. Antibacterial properties on S. mutans were assessed via CFU counting, CLSM, and SEM observation. SPSS 26.0 was used for statistical analysis (α = 0.05). RESULTS: The mechanical properties were material-dependent and sensitive to water storage. Flexural strength ranked GU > FS > BI > DF at all testing levels. Three nanocomposites had better wear properties than DF. No significant difference on 1-day cell viability was found, but DF showed significantly lower cell proliferation than nanocomposites on 3-day assessment. GU and FS had more favourable cell adhesion and morphology. CFU counting revealed no significant difference, while FS presented a slightly thicker biofilm and BI showed relatively lower bacteria density. CONCLUSIONS: Injectable nanocomposites outperformed the compomer regarding mechanical properties, wear resistance, and biocompatibility. The tested materials presented comparable antibacterial behaviours. Flowable resin-based composites' performances are affected by multiple factors, and their compositions can be attributed. CLINICAL SIGNIFICANCE: A profound understanding of the mechanical, wear, and biological properties of the restorative material is imperative for the clinical success of dental restorations. The current study demonstrated superior properties of highly filled injectable composite resins, which imply their wider indications and better long-term clinical performances.

Magnetic Hydroxyapatite-Coated Iron-Chromium Microspheres for Dental Surface Polishing and Plaque Removal.

This research aimed to engineer magnetic hydroxyapatite-coated iron-chromium (HAp-FeCr) microspheres to enhance dental surface polishing and plaque elimination. Utilizing a tailored sol-gel approach, the HAp-FeCr microspheres were synthesized and exhaustively characterized via scanning electron microscopy, energy-dispersive X-ray spectroscopy, ζ-potential, X-ray diffractometry, and X-ray photoelectron spectroscopy methodologies. Key findings showcased that these microspheres retained their magnetic properties post-HAp coating, as evidenced by the magnetization curves. An innovative magnetic polishing system was developed, incorporating these microspheres and a 2000 rpm magnet. Comparative evaluations between traditional air-powder polishing and the proposed magnetic technique demonstrated the latter's superiority. Notably, the magnetic polishing led to a substantial reduction in dental plaque on the tooth surface, decreasing bacterial adhesion and early biofilm formation by Streptococcus gordonii and Lactobacillus acidophilus, where the most pronounced effects were observed in samples with elevated HAp content. A significant 60% reduction in dental plaque was achieved with the magnetic method relative to air-powder polishing. Furthermore, the HAp-FeCr microspheres' biocompatibility was verified through cytotoxicity tests and animal studies. In essence, the magnetic HAp-FeCr microspheres present a novel and efficient strategy for dental treatments, holding immense potential for improving oral health.

The effect of the "Oral-Gut" axis on periodontitis in inflammatory bowel disease: A review of microbe and immune mechanism associations.

Periodontitis and inflammatory bowel diseases (IBD) are inflammatory diseases of the gastrointestinal tract that share common features of microbial-induced ecological dysregulation and host immune inflammatory response. The close relationship between periodontitis and IBD is characterized by a higher prevalence of IBD in patients with periodontitis and a higher prevalence and severity of periodontitis in patients with IBD, indicating that periodontitis and IBD are different from the traditional independent diseases and form an "Oral-Gut" axis between the two, which affect each other and thus form a vicious circle. However, the specific mechanisms leading to the association between the two are not fully understood. In this article, we describe the interconnection between periodontitis and IBD in terms of microbial pathogenesis and immune dysregulation, including the ectopic colonization of the gut by pathogenic bacteria associated with periodontitis that promotes inflammation in the gut by activating the host immune response, and the alteration of the oral microbiota due to IBD that affects the periodontal inflammatory response. Among the microbial factors, pathogenic bacteria such as Klebsiella, Porphyromonas gingivalis and Fusobacterium nucleatum may act as the microbial bridge between periodontitis and IBD, while among the immune mechanisms, Th17 cell responses and the secreted pro-inflammatory factors IL-1ß, IL-6 and TNF-α play a key role in the development of both diseases. This suggests that in future studies, we can look for targets in the "Oral-Gut" axis to control and intervene in periodontal inflammation by regulating periodontal or intestinal flora through immunological methods.

Local administration of liposomal-based Plekhf1 gene therapy attenuates pulmonary fibrosis by modulating macrophage polarization.

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with limited therapeutic options. Macrophages, particularly alternatively activated macrophages (M2), have been recognized to contribute to the pathogenesis of pulmonary fibrosis. Therefore, targeting macrophages might be a viable therapeutic strategy for IPF. Herein, we report a potential nanomedicine-based gene therapy for IPF by modulating macrophage M2 activation. In this study, we illustrated that the levels of pleckstrin homology and FYVE domain containing 1 (Plekhf1) were increased in the lungs originating from IPF patients and PF mice. Further functionality studies identified the pivotal role of Plekhf1 in macrophage M2 activation. Mechanistically, Plekhf1 was upregulated by IL-4/IL-13 stimulation, after which Plekhf1 enhanced PI3K/Akt signaling to promote the macrophage M2 program and exacerbate pulmonary fibrosis. Therefore, intratracheal administration of Plekhf1 siRNA-loaded liposomes could effectively suppress the expression of Plekhf1 in the lungs and notably protect mice against BLM-induced lung injury and fibrosis, concomitant with a significant reduction in M2 macrophage accumulation in the lungs. In conclusion, Plekhf1 may play a crucial role in the pathogenesis of pulmonary fibrosis, and Plekhf1 siRNA-loaded liposomes might be a promising therapeutic approach against pulmonary fibrosis.

Gut microbiota-dependent trimethylamine n-oxide pathway contributes to the bidirectional relationship between intestinal inflammation and periodontitis.

Background: Intestinal inflammation and periodontitis influence the development of each other through the bidirectional relationship. As the intestinal microbiome metabolite, trimethylamine-N-oxide (TMAO) could contribute to chronic inflammation in the gut by influencing the gut microbial composition and intestinal immunity. Increased circulating TMAO levels often accompany clinical findings in patients with experimental periodontitis. However, the role of TMAO in the bidirectional relationship between intestinal inflammation and periodontitis remains unclear. Thus, we explored whether TMAO influences the periodontitis process by affecting intestinal immunity and microbial composition in this article. Methods: Periodontitis was induced by unilateral ligation of the first molar in mice, and 3,3-dimethyl-1-butanol (DMB) was used as an inhibitor to reduce TMAO circulating. Twenty-five BALB/c mice were randomly assigned to five study sets (n = 5/group): no periodontitis with DMB (Control group), periodontitis (P) group, periodontitis with TMAO (P+TMAO) group, periodontitis with TMAO and DMB (P+TMAO+DMB) group, and periodontitis with DMB (P+DMB) group. The effect of TMAO was determined by assessing changes in intestinal histology, intestinal flora composition, periodontal tissue, and periodontal pro-inflammatory factors at ten days. Results: The outcomes indicated a marked improvement in the intestinal inflammation severity, and intestinal flora diversity was reduced. Firmicutes number and the ratio of Firmicutes/Bacteroidetes were improved in the P+TMAO group. In addition, the alveolar bone resorption and the degree of periodontal tissue inflammation were more severe in the P+TMAO group than in other groups. Immunohistochemistry showed higher levels of TGF-ß and IL-1ß expression in the periodontal tissues of P+TMAO. Conclusions: Our data suggest that TMAO could influence periodontal immunity and promote periodontal inflammation by affecting the intestinal microenvironment, revealing TMAO may affect the development of periodontitis through the bidirectional relationship of the oral-gut axis.

Gold nanoparticle decoration potentiate the antibacterial enhancement of TiO2 nanotubes via sonodynamic therapy against peri-implant infections.

Inflammatory damage from bacterial biofilms usually causes the failure of tooth implantation. A promising solution for this challenge is to use an implant surface with a long-term, in-depth and efficient antibacterial feature. In this study, we developed an ultrasound-enhanced antibacterial implant surface based on Au nanoparticle modified TiO2 nanotubes (AuNPs-TNTs). As an artificial tooth surface, films based on AuNPs-TNTs showed excellent biocompatibility. Importantly, compared to bare titania surface, a larger amount of reactive oxygen radicals was generated on AuNPs-TNTs under an ultrasound treatment. For a proof-of-concept application, Porphyromonas gingivalis (P. gingivalis) was used as the model bacteria; the as-proposed AuNPs-TNTs exhibited significantly enhanced antibacterial activity under a simple ultrasound treatment. This antibacterial film offers a new way to design the surface of an artificial implant coating for resolving the bacterial infection induced failure of dental implants.

A high-performance SERS imprinted membrane based on Ag/CNTs for selective detection of spiramycin.

In this test, the eggshell membrane (ESM) is selected as the support membrane for the biocompatibility and anchors CNTs on the surface to increase the mechanical properties. Then Ag NPs are decorated on CNTs-ESM substrate as SERS substrate by twice in-situ reduction. Finally, a layer of imprinted polymers is coated on the surface of the substrate to synthesize the imprinted membrane for selective detection of spiramycin. It is exhibited from the characteristic results that the CNTs significantly increase the mechanical properties and the detection sensitivity, simultaneously. When the concentration of SP changes between 10-6 âˆ¼ 10-11 M, there is a linear relationship between SERS intensity and SP concentration. The detection limit is 10-11 M, and the correlation coefficient R2 is 0.9864. The SERS imprinted membrane can be applied into the detection of antibiotics in practical sample, which broadens the research field of antibiotics detection.

Single-hole hollow molecularly imprinted polymer embedded carbon dot for fast detection of tetracycline in honey.

It is difficult to detect tetracycline (TC) in honey sample by using carbon dots (CDs) because the autofluorescence of the matrix of honey sample overlaps with the fluorescence emission spectrum of the large majority of CDs. Herein, single-hole hollow molecularly imprinted polymers embedded carbon dots (HMIP@CD) was prepared via microwave-assisted method. TC in diluted honey sample was adsorbed by the HMIP@CD within 3 min, after which the HMIP@CD absorbed with TC was separated by centrifugation from honey sample and redispersed into phosphate buffer solution. The autofluorescence of honey that interferes with the fluorescence signal of HMIP@CD was avoided. The method exhibited an excellent linearity within 10-200 µg L-1 and a low detection limit of 3.1 µg L-1. At three spiking levels of TC, the recoveries ranged from 93% to 105% with precisions below 1.6%. This method provides an effective strategy for detecting analyte in complex matrix with autofluorescence interference.

Rapid microwave-assisted synthesis of molecularly imprinted polymers on carbon quantum dots for fluorescent sensing of tetracycline in milk.

In this paper, a novel, selective and eco-friendly sensor for the detection of tetracycline was developed by grafting imprinted polymers onto the surface of carbon quantum dots. A simple microwave-assisted approach was utilized to fabricate the fluorescent imprinted composites rapidly for the first time, which could shorten the polymerization time and simplify the experimental procedure dramatically. The novel composites not only demonstrated excellent fluorescence stability and special binding sites, but also could selectively accumulate target analytes. Under optimal conditions, the relative fluorescence intensity of the composites decreased linearly with increasing the concentration of tetracycline from 20 nM to 14 µM. The detection limit of tetracycline was 5.48 nM. The precision and reproducibility of the proposed sensor were also acceptable. Significantly, the practicality of this ultrasensitive sensor for tetracycline detection in milk was further validated, revealing the advantages of simplicity, sensitivity, selectivity and low cost. This approach combines the high selective adsorption property of molecular imprinted polymers and the sensitivity of fluorescence detection. It is envisioned that the development of fluorescent molecularly imprinted composites will offer a new way of thinking for rapid analysis in complex samples.