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1.
Proc Natl Acad Sci U S A ; 121(40): e2403380121, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39331412

RESUMO

Flexible intracortical probes offer important opportunities for stable neural interfaces by reducing chronic immune responses, but their advances usually come with challenges of difficult implantation and limited recording span. Here, we reported a mechanically adaptive and deployable intracortical probe, which features a foldable fishbone-like structural design with branching electrodes on a temperature-responsive shape memory polymer (SMP) substrate. Leveraging the temperature-triggered soft-rigid phase transition and shape memory characteristic of SMP, this probe design enables direct insertion into brain tissue with minimal footprint in a folded configuration while automatically softening to reduce mechanical mismatches with brain tissue and deploying electrodes to a broader recording span under physiological conditions. Experimental and numerical studies on the material softening and structural folding-deploying behaviors provide insights into the design, fabrication, and operation of the intracortical probes. The chronically implanted neural probe in the rat cortex demonstrates that the proposed neural probe can reliably detect and track individual units for months with stable impedance and signal amplitude during long-term implantation. The work provides a tool for stable neural activity recording and creates engineering opportunities in basic neuroscience and clinical applications.


Assuntos
Eletrodos Implantados , Animais , Ratos , Fenômenos Eletrofisiológicos , Polímeros/química , Córtex Cerebral/fisiologia , Neurônios/fisiologia , Ratos Sprague-Dawley , Encéfalo/fisiologia
2.
Chembiochem ; 24(16): e202300132, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37340829

RESUMO

Self-assembly of block copolymers has recently drawn great attention due to its remarkable performance and wide variety of applications in biomedicine, biomaterials, microelectronics, photoelectric materials, catalysts, etc. Poly(amino acid)s (PAAs), formed by introducing synthetic amino acids into copolymer backbones, are able to fold into different secondary conformations when compared with traditional amphiphilic copolymers. Apart from changing the chemical composition and degree of polymerization of copolymers, the self-assembly behaviors of PAAs could be controlled by their secondary conformations, which are more flexible and adjustable for fine structure tailoring. In this article, we summarize the latest findings on the variables that influence secondary conformations, in particular the regulation of order-to-order conformational changes and the approaches used to manage the self-assembly behaviors of PAAs. These strategies include controlling pH, redox reactions, coordination, light, temperature, and so on. Hopefully, we can provide valuable perspectives that will be useful for the future development and use of synthetic PAAs.


Assuntos
Aminoácidos , Polímeros , Polímeros/química , Conformação Molecular , Polimerização , Micelas
3.
Angew Chem Int Ed Engl ; 62(6): e202213000, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36353928

RESUMO

Metal ions play critical roles in facilitating peptide folding and inducing conformational transitions, thereby impacting on the biological activity of many proteins. However, the effect of metal sites on the hierarchical structures of biopolymers is still poorly understood. Herein, inspired by metalloproteins, we report an order-to-order conformational regulation in synthetic polymers mediated by a variety of metal ions. The copolymers are decorated with clinically available desferrioxamine (DFO) as an exogenous ligand template, which presents a geometric constraint toward peptide backbone via short-range hydrogen bonding interactions, thus dramatically altering the secondary conformations and self-assembly behaviors of polypeptides and allowing for a controllable ß-sheet to α-helix transition modulated by metal-ligand interactions. These metallopolymers could form ferritin-inspired hierarchical structures with high stability and membrane activity for efficient brain delivery across the blood-brain barrier (BBB) and long-lasting magnetic resonance imaging (MRI) in vivo.


Assuntos
Polímeros , Proteínas , Polímeros/química , Ligantes , Peptídeos/química , Metais/química , Íons
4.
J Sci Food Agric ; 102(5): 2070-2079, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-34569077

RESUMO

BACKGROUND: Norbixin, a carotenoid extracted from annatto seeds, is widely utilized as a natural pigment in foods, cosmetics and medicines. Its water solubility is relatively high under neutral or alkaline conditions but low under acidic conditions, which limits its application in some food products. RESULTS: This problem was overcome by utilizing liposomes to encapsulate the carotenoids so that they could be easily dispersed within acidic solutions. The norbixin was loaded into the liposomes using the pH-driven method. Liposomes were produced by passing aqueous phospholipid dispersions through a microfluidizer under high pressure. Norbixin was then added to the liposome dispersions at pH 7.0 and then driven into the hydrophobic domains of the phospholipid bilayers by acidifying the system. Measurements of the encapsulation efficiency showed that the norbixin was successfully loaded into the liposomes using the pH-driven method. X-ray diffraction analysis showed that the norbixin was in an amorphous state after incorporation into the liposomes. Encapsulation of norbixin within the liposomes was also shown to increase its water dispersibility and chemical stability under acidic pH conditions. CONCLUSION: The pH-driven method therefore provides a useful means of increasing the application of this bioactive carotenoid within functional foods and other products. © 2021 Society of Chemical Industry.


Assuntos
Carotenoides , Lipossomos , Carotenoides/química , Concentração de Íons de Hidrogênio , Lipossomos/química , Solubilidade
5.
Mol Pharm ; 18(11): 4170-4178, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34582196

RESUMO

Tailing off release in the sustained release of water-insoluble curcumin (Cur) is a significant challenge in the drug delivery system. As a novel solution, core-shell nanodrug containers have aroused many interests due to their potential improvement in drug-sustained release. In this work, a biodegradable polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and hydrophilic polyvinylpyrrolidone (PVP) were exploited as drug delivery carriers by coaxial electrospinning, and the core-shell drug-loaded fibers exhibited improved sustained release of Cur. A cylindrical morphology and a clear core-shell structure were observed by scanning and transmission electron microscopies. The X-ray diffraction pattern and infrared spectroscopy revealed that Cur existed in amorphous form due to its good compatibility with PHBV and PVP. The in vitro drug release curves confirmed that the core-shell container manipulated Cur in a faster drug release process than that in the traditional PHBV monolithic container. The combination of the material and structure forms a novel nanodrug container with a better sustained release of water-insoluble Cur. This strategy is beneficial for exploiting more functional biomedical materials to improve the drug release behavior.


Assuntos
Curcumina/farmacocinética , Composição de Medicamentos/métodos , Sistemas de Liberação de Fármacos por Nanopartículas/química , Curcumina/administração & dosagem , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/farmacocinética , Liberação Controlada de Fármacos , Poliésteres/química , Povidona/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
J Craniofac Surg ; 31(8): 2193-2198, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33136853

RESUMO

The aim of this study is to evaluate the osteogenesis around titanium implant and in bone defect or fracture in jaw bones and long bones in ovariectomized (OVX) animal models. The literature on the osteogenesis around titanium implant and in bone defect or fracture in jaw bones and long bones was reviewed with charts. Fourty-eight rats were randomly divided into OVX group with ovariectomy and SHAM (sham-surgery) group with sham surgery. Titanium implants were inserted in the right mandibles and tibiae; bone defects were created in the left mandibles and tibiae. Two-week postoperatively, mandibles and tibiae of 8 rats were harvested and examined by hematoxylin and eosin staining and histological analysis; 4-week postoperatively, all mandibles and tibiae were harvested and examined by Micro-CT and histological analysis. A total of 52 articles were included in this literature review. Tibial osteogenesis around titanium implant and in bone defect in OVX group were significantly decreased compared with SHAM group. However, osteogenesis differences in the mandible both around titanium implant and in bone defect between groups were not statistically significant. OVX-induced osteoporosis suppresses osteogenesis around titanium implant and in the bone defect or fracture in long bones significantly while has less effect on that in the jaw bones.


Assuntos
Implantes Experimentais/efeitos adversos , Arcada Osseodentária/efeitos dos fármacos , Tíbia/efeitos dos fármacos , Titânio/farmacologia , Animais , Feminino , Procedimentos Cirúrgicos Ortognáticos , Osteogênese/efeitos dos fármacos , Osteoporose/induzido quimicamente , Osteoporose/patologia , Ovariectomia , Ratos , Tíbia/cirurgia
7.
BMC Oral Health ; 20(1): 204, 2020 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-32652980

RESUMO

BACKGROUND: To systematically review the epidemiologic relationship between periodontitis and type 2 diabetes mellitus (T2DM). METHODS: Four electronic databases were searched up until December 2018. The manual search included the reference lists of the included studies and relevant journals. Observational studies evaluating the relationship between T2DM and periodontitis were included. Meta-analyses were conducted using STATA. RESULTS: A total of 53 observational studies were included. The Adjusted T2DM prevalence was significantly higher in periodontitis patients (OR = 4.04, p = 0.000), and vice versa (OR = 1.58, p = 0.000). T2DM patients had significantly worse periodontal status, as reflected in a 0.61 mm deeper periodontal pocket, a 0.89 mm higher attachment loss and approximately 2 more lost teeth (all p = 0.000), than those without T2DM. The results of the cohort studies found that T2DM could elevate the risk of developing periodontitis by 34% (p = 0.002). The glycemic control of T2DM patients might result in different periodontitis outcomes. Severe periodontitis increased the incidence of T2DM by 53% (p = 0.000), and this result was stable. In contrast, the impact of mild periodontitis on T2DM incidence (RR = 1.28, p = 0.007) was less robust. CONCLUSIONS: There is an evident bidirectional relationship between T2DM and periodontitis. Further well-designed cohort studies are needed to confirm this finding. Our results suggest that both dentists and physicians need to be aware of the strong connection between periodontitis and T2DM. Controlling these two diseases might help prevent each other's incidence.


Assuntos
Diabetes Mellitus Tipo 2 , Periodontite , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Humanos , Bolsa Periodontal , Periodontite/complicações , Periodontite/epidemiologia
8.
Nanotechnology ; 30(6): 065102, 2019 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-30543196

RESUMO

Transition metal dichalogenides (TMDCs) with unique layered structures hold promising potential as transducers for photothermal therapy. However, the low photothermal conversion efficiency and poor stability in some cases limit their practical applications. Herein, we demonstrate the fabrication of ultrathin homogeneous hybridized TMDC nanosheets and their use for highly efficient photothermal tumor ablation. In particular, the nanosheets were composed of metallic WSe2 intercalated with polyvinylpyrrolidone (PVP), which was facilely prepared through a solvothermal process from the mixture of selenourea crystals, WCl6 powder along with PVP polymeric nanogel. Our characterizations revealed that the obtained nanosheets exhibited excellent photothermal conversion efficiency, therapeutic demonstration with improved biocompatibility and physiological stability attributing to the combined merits of metallic phase of WSe2 and hydrophilic PVP insertion. Both the histological analysis of vital organs and in vitro/in vivo tests confirmed the nanosheets as actively effective and biologically safe in this phototherapeutic technique. Findings from this non-invasive experiment clearly emphasize the explorable therapeutic efficacy of the layered-based hybrid agents in future cancer treatment planning procedures.


Assuntos
Fármacos Fotossensibilizantes/uso terapêutico , Fototerapia/métodos , Povidona/química , Selênio/química , Tungstênio/química , Animais , Linhagem Celular Tumoral , Feminino , Raios Infravermelhos/uso terapêutico , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/química , Neoplasias Experimentais/terapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Temperatura , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Int J Adhes Adhes ; 92: 73-79, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32042213

RESUMO

The present work aims to investigate if a novel self-cure system, mediated by tertiary amine ethyl 4-(dimethylamino)-benzoate (4E) and tooth mineral hydroxyapatite (HAp), would trigger polymerization of model adhesives based on a popular self-etch monomer, 10- methacryloyloxydecyl dihydrogen phosphate (10-MDP). The effect of 4E and HAp contents on degree of conversion (DC), polymerization rate (Rp), and induction period (IP) was investigated. The occurrence of such self-cure phenomenon in adhesives that underwent prior inadequate light cure was also evaluated. Model self-etch adhesives were prepared by using a monomer mixture of 10-MDP with 2-hydroxyethyl methacrylate at1:1 wt. ratio. 4E (0.3-1.3 wt%), and HAp (0.5-2 wt%) were added to the mixture. Benzoylperoxide and N,N-dihydroxyethyl-p-toluidine were used as conventional chemical-cure system, and trimethylbenzoyl-diphenylphosphine oxide as light-curing photoinitiator. The polymerization processes and mechanical properties of model adhesives were evaluated by real time ATR/FT-IR and nanoindentation, respectively. The 4E- HAp system successfully triggered self-cure of 10-MDP based model adhesives. DC, Rp and IP were apparently affected by both 4E and HAp contents. DC of self-cure of the model adhesives was much higher than that of the conventional chemical-cure system. 4E-HAp initiated self-cure further boosted DC to ~100% regardless of prior light exposure, and significantly improved elastic modulus and hardness, thus provided a novel polymerization method to effectively salvage curing of the adhesives after inadequate light-cure.

10.
BMC Pediatr ; 15: 105, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26315551

RESUMO

BACKGROUND: The aim of this study was to investigate and compare the injury pattern, mechanisms, severity, and mortality of adolescents and adults hospitalized for treatment of trauma following motorcycle accidents in a Level I trauma center. METHODS: Detailed data regarding patients aged 13-19 years (adolescents) and aged 30-50 years (adults) who had sustained trauma due to a motorcycle accident were retrieved from the Trauma Registry System between January 1, 2009 and December 31, 2012. The Pearson's chi-squared test, Fisher's exact test, or the independent Student's t-test were performed to compare the adolescent and adult motorcyclists and to compare the motorcycle drivers and motorcycle pillion. RESULTS: Analysis of Abbreviated Injury Scale (AIS) scores revealed that the adolescent patients had sustained higher rates of facial, abdominal, and hepatic injury and of cranial, mandibular, and femoral fracture but lower rates of thorax and extremity injury; hemothorax; and rib, scapular, clavicle, and humeral fracture compared to the adults. No significant differences were found between the adolescents and adults regarding Injury Severity Score (ISS), New Injury Severity Score (NISS), Trauma-Injury Severity Score (TRISS), mortality, length of hospital stay, or intensive care unit (ICU) admission rate. A significantly greater percentage of adolescents compared to adults were found not to have worn a helmet. Motorcycle riders who had not worn a helmet were found to have a significantly lower first Glasgow Coma Scale (GCS) score, and a significantly higher percentage was found to present with unconscious status, head and neck injury, and cranial fracture compared to those who had worn a helmet. CONCLUSION: Adolescent motorcycle riders comprise a major population of patients hospitalized for treatment of trauma. This population tends to present with a higher injury severity compared to other hospitalized trauma patients and a bodily injury pattern differing from that of adult motorcycle riders, indicating the need to emphasize use of protective equipment, especially helmets, to reduce their rate and severity of injury.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Motocicletas , Ferimentos e Lesões/epidemiologia , Acidentes de Trânsito/mortalidade , Acidentes de Trânsito/prevenção & controle , Adolescente , Adulto , Estudos Transversais , Feminino , Dispositivos de Proteção da Cabeça/estatística & dados numéricos , Humanos , Escala de Gravidade do Ferimento , Unidades de Terapia Intensiva/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Taiwan/epidemiologia , Centros de Traumatologia/estatística & dados numéricos , Ferimentos e Lesões/mortalidade , Ferimentos e Lesões/prevenção & controle , Adulto Jovem
11.
Macromol Rapid Commun ; 35(16): 1436-42, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24957975

RESUMO

This paper describes a method for fabricating protein-based capsules with semipermeable and enzyme-degradable surface barriers. It involves the use of a simple fluidic device to generate water-in-oil emulsion droplets, followed by cross-linking of proteins at the water-oil interface to generate a semipermeable surface barrier. The capsules can be readily fabricated with uniform and controllable sizes and, more importantly, show selective permeability toward molecules with different molecular weights: small molecules like fluorescein sodium salt can freely diffuse through the surface barrier while macromolecules such as proteins can not. The proteins, however, can be released by digesting the surface barrier with an enzyme such as pepsin. Taken together, the capsules hold great potential for applications in controlled release, in particular, for the delivery of protein drugs.


Assuntos
Cápsulas/química , Pepsina A/metabolismo , Proteínas/metabolismo , Animais , Cápsulas/toxicidade , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Preparações de Ação Retardada , Emulsões/química , Fluoresceína-5-Isotiocianato/química , Fluoresceína-5-Isotiocianato/metabolismo , Camundongos , Células NIH 3T3 , Óleos/química , Permeabilidade , Polímeros/química , Proteínas/química , Albumina Sérica/química , Albumina Sérica/metabolismo , Propriedades de Superfície , Água/química
12.
Environ Pollut ; 341: 122976, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37984473

RESUMO

The ubiquitous occurrence of microplastics in water and wastewater is a growing concern. In this study, the chemical transformation and organic release of virgin and UV-aged thermoplastic polyurethane (TPU) polymers during chlorination were investigated. As compared to virgin TPU polymer, the UV-aged TPU polymer exhibited high chlorine reactivity with noticeable destruction on its surface functional groups after chlorination, which could be ascribed to the UV-induced activation of hard segment of TPU backbone and increased contact area. The concentrations of leached organics increased by 1.6-fold with obviously high abundances of low-molecular-weight components. Additives, monomers, compounds relating to TPU chain extension, and their chlorination byproducts contributed to the increased organic release. Meanwhile, the formation of chloroform, haloacetic acids, trichloroacetaldehyde, and dichloroacetonitrile increased by 3.8-, 1.7-, 4.9-, and 2.4-fold, respectively. Two additives and six chlorination byproducts in leachate from chlorinated UV-aged TPU were predicted as highly toxic, e.g., butyl octyl phthalate, palmitic acid, 2,6-di-tert-butyl-1,4-benzoquinone, and chlorinated aniline. Evaluated by human hepatocarcinoma cells, the 50% lethal concentration factor of organics released from chlorinated UV-aged TPU was approximately 10% of that from its virgin counterpart, indicating a substantially increased level of cytotoxicity. This study highlights that the release of additives and chlorination byproducts from the chemical transformation of UV-aged microplastics during chlorination may be of potentially toxic concern.


Assuntos
Desinfetantes , Poluentes Químicos da Água , Purificação da Água , Humanos , Idoso , Desinfecção , Microplásticos , Plásticos , Poliuretanos , Halogenação , Poluentes Químicos da Água/análise , Cloro/química
13.
ACS Appl Bio Mater ; 7(8): 5771-5779, 2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39110771

RESUMO

Nanomaterials with photoresponsivity have garnered attention due to their fluorescence imaging, photodynamic, and photothermal therapeutic properties. In this study, a photoresponsivity nanoassembly was developed by using photosensitizers and carbon dots (CDs). Due to their multiple excitation peaks and multicolor fluorescence emission, especially their membrane-permeating properties, these nanoassemblies can label cells with multiple colors and track cell imaging in real time. Additionally, the incorporation of photosensitizers and CDs provides the nanoassemblies with the potential for photodynamic therapy (PDT) and photothermal therapy (PTT). The nanoassemblies effectively suppressed the activity of Escherichia coli and Staphylococcus aureus through PDT and PTT. Moreover, the nanoassemblies exhibited a high affinity for E. coli and S. aureus. These distinct features confer broad-spectrum antibacterial properties to the nanoassemblies. As a photoresponsivity nanoplatform, these nanoassemblies have demonstrated potential applications in the fields of bioimaging and antimicrobial.


Assuntos
Antibacterianos , Materiais Biocompatíveis , Escherichia coli , Teste de Materiais , Tamanho da Partícula , Fármacos Fotossensibilizantes , Staphylococcus aureus , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Testes de Sensibilidade Microbiana , Humanos , Pontos Quânticos/química , Nanoestruturas/química , Carbono/química , Carbono/farmacologia , Imagem Óptica , Fotoquimioterapia , Sobrevivência Celular/efeitos dos fármacos
14.
Adv Healthc Mater ; 13(18): e2303549, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38333940

RESUMO

Periodontitis is a common oral disease accompanied by inflammatory bone loss. The pathological characteristics of periodontitis usually accompany an imbalance in the periodontal immune microenvironment, leading to difficulty in bone regeneration. Therefore, effective treatment strategies are needed to modulate the immune environment in order to treat periodontitis. Here, highly-oriented periodic lamellae poly(ε-caprolactone) electrospun nanofibers (PLN) are developed by surface-directed epitaxial crystallization. The in vitro result shows that the PLN can precisely modulate macrophage polarization toward the M2 phenotype. Macrophages polarized by PLN significantly enhance the migration and osteogenic differentiation of Bone marrow stromal cells. Notably, results suggest that the topographical cues presented by PLN can modulate macrophage polarization by activating YAP, which reciprocally inhibits the NF-κB signaling pathway. The in vivo results indicate that PLN can inhibit inflammatory bone loss and facilitate bone regeneration in periodontitis. The authors' findings suggest that topographical nanofibers with periodic lamellae is a promising strategy for modulating immune environment to treat inflammatory bone loss in periodontitis.


Assuntos
Nanofibras , Osteogênese , Periodontite , Poliésteres , Nanofibras/química , Periodontite/terapia , Periodontite/patologia , Periodontite/imunologia , Periodontite/tratamento farmacológico , Animais , Camundongos , Poliésteres/química , Osteogênese/efeitos dos fármacos , Células RAW 264.7 , Macrófagos/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Regeneração Óssea/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , NF-kappa B/metabolismo , Células-Tronco Mesenquimais/imunologia , Imunomodulação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Camundongos Endogâmicos C57BL , Masculino , Inflamação/patologia , Proteínas de Sinalização YAP
15.
Dent Mater ; 39(11): 1004-1012, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37734971

RESUMO

OBJECTIVES: To develop dual-functional etchants that could demineralize and stabilize dentin collagen simultaneously, and to assess the effects of these etchants on collagen crosslinking, biostability and resin bonding properties under clinically relevant conditions. METHODS: Dual-functional etchants were prepared by mixing 56% glycolic acid and 17% phosphoric acid and adding 1% of theaflavins (TF) or proanthocyanidins from grape seed extract (GSE). The etchant without crosslinker was used as control. The prepared human dentin specimens were treated with the 3 etchants for 30 s and analyzed for chemical interaction using Fourier transform infrared spectroscopy and resistance of the demineralized layer to collagenase degradation using electron microscopy (EM). Resin-dentin interfacial bonding properties were evaluated after 24 h and after 10,000 thermocycling through microtensile bond strength (µTBS), nanoleakage and matrix metalloproteinases (MMPs) activity via in situ zymography. Statistical analysis was done using ANOVA and post- hoc Tuckey's test. RESULTS: Compared to control, TF and GSE dual-functional etchants were able to demineralize dentin, induce collagen crosslinking and protect the demineralized layer from collagenase degradation within 30 s. High resolution EM images showed better protection with TF etchant compared to GSE. There was a significant reduction in µTBS and an increase in nanoleakage and MMPs activity in control after thermocycling (p < 0.05) while these changes weren't seen in dual-functional etchants. SIGNIFICANCE: Dual-functional etchants, especially TF containing, provide collagen protection against degradation and result in stable µTBS and less nanoleakage and MMPs activity under clinically relevant conditions.

16.
Sci Total Environ ; 858(Pt 2): 159842, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36374755

RESUMO

The presence and accumulation of microplastics (MPs) in water and wastewater is a growing concern. When released to the water bodies, microplastics can be subject to surface weathering due to ultraviolet (UV) exposure. In this study, the effects of UV aging of six MP polymers from three groups (e.g., polyamide, polyester, and polyolefin) on their chlorine reactivity, chemical transformation, and formation of disinfection byproducts (DBPs) were studied. Polyamide (e.g., polyamide 6) in both virgin and UV-aged forms showed significantly higher chlorine demands than other MP polymers (915.5-947.9 versus 7.0-21.1 µmol/g MP in 24 h), and polyolefins were relatively inert to chlorine. UV aging enhanced the destructions of functional groups of polyamide and polyester upon chlorination, promoting the chlorine demands and leaching of organics by up to 1.7- and 2.4-fold, respectively. Polymer monomer and oligomers of polyamide 6 and toxic or endocrine disrupting additives (e.g., dimethyl phthalate and butyl octyl phthalate) were identified in leachates from chlorinated MP polymers by mass spectrometry. Meanwhile, up to >10-fold increases in the yields of trihalomethane, haloacetic acid, haloacetaldehyde, haloacetonitrile, and haloacetamide were observed from 30-day UV-aged MP polymers as compared to their virgin counterparts. Overall, this study reveals that UV aging can promote the reactivity and chemical transformation of MP polymers during chlorination, especially for polyamide and polyester, increase the release of polymer monomers, oligomers, and additives, and aggravate the role of MP polymers as DBP precursors.


Assuntos
Desinfetantes , Poluentes Químicos da Água , Purificação da Água , Microplásticos , Halogenação , Cloro/química , Plásticos , Nylons , Desinfecção/métodos , Polímeros , Água , Poliésteres , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Desinfetantes/análise
17.
Chemosphere ; 337: 139360, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37392793

RESUMO

The usage of biodegradable plastics is expanding annually due to worldwide plastic limits, resulting in a substantial number of microplastics (MPs) particles formed from biodegradable plastic products entering the aquatic environment. Until now, the environmental behaviors of these plastic product-derived MPs (PPDMPs) have remained unclear. In this work, commercially available polylactic acid (PLA) straws and PLA food bags were used to evaluate the dynamic aging process and environmental behavior of PLA PPDMPs under UV/H2O2 conditions. By combining scanning electron microscopy, two-dimensional (2D) Fourier transform infrared correlation spectroscopy (COS) and X-ray photoelectron spectroscopy, it was determined that the aging process of the PLA PPDMPs was slower than that of pure MPs. The 2D-COS analysis revealed that the response orders for the functional groups on the PLA MPs differed during the aging process. The results demonstrated that the oxygen-containing functional groups of the PLA PPDMPs were the first to react. Subsequently, the -C-H and -C-C- structural responses began, and the polymer backbone was ruptured by the aging process. However, the aging of the pure-PLA MPs started with a brief oxidation process and then breakage of the polymer backbones, followed by continuous oxidation. Moreover, compared to the PLA PPDMPs, the pure-PLA MPs exhibited a greater adsorption capacity, which was increased by 88% after aging, whereas those of the two PPDMPs only increased by 64% and 56%, respectively. This work provides new insights into the behaviors of biodegradable PLA MPs in aquatic environments, which is critical for assessing the environmental risks and management policies for degradable MPs.


Assuntos
Plásticos Biodegradáveis , Poluentes Químicos da Água , Microplásticos , Plásticos , Peróxido de Hidrogênio , Poliésteres , Polímeros
18.
Chemosphere ; 311(Pt 1): 136938, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36280118

RESUMO

Dissolved organic matter regulates the interaction between microplastics (MPs) and organic pollutants. Here, this paper investigated the effect and mechanism of humic acid (HA) on the adsorption behavior of thiacloprid at two microfibers (MFs)/water interface, and compared the differences in the performance of MFs and pure MPs. The results showed that 10 mg L-1 HA decreased the adsorption capacity and the partition coefficient KD of thiacloprid on MFs and pure MPs. Spectral analysis showed that HA could form hydrogen bonds and van der Waals forces with both MPs and thiacloprid, ultimately affecting the adsorption behavior of thiacloprid at MPs/water interface via competitive adsorption and bridging effect. Furthermore, two-dimensional correlation spectroscopy demonstrated that thiacloprid was preferentially adsorbed onto MPs compared with HA. Finally, density functional theory calculation demonstrated that phenolic-OH, -COOH, and alcoholic-OH played critical roles in competing adsorption and bridging effect. This study offers a theoretical foundation for a better comprehension of the adsorption behavior of organic pollutants at the MPs/water interface.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Substâncias Húmicas , Adsorção , Água/química , Plásticos , Microplásticos , Poluentes Químicos da Água/análise
19.
Biomolecules ; 13(1)2023 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-36671570

RESUMO

Herbal medicine has a long history of medical efficacy with low toxicity, side effects and good biocompatibility. However, the bioavailability of the extract of raw herbs and bioactive compounds is poor because of their low water solubility. In order to overcome the solubility issues, electrospinning technology can offer a delivery alternative to resolve them. The electrospun fibers have the advantages of high specific surface area, high porosity, excellent mechanical strength and flexible structures. At the same time, various natural and synthetic polymer-bound fibers can mimic extracellular matrix applications in different medical fields. In this paper, the development of electrospinning technology and polymers used for incorporating herbal medicine into electrospun nanofibers are reviewed. Finally, the recent progress of the applications of these herbal medicine nanofibers in biomedical (drug delivery, wound dressing, tissue engineering) and food fields along with their future prospects is discussed.


Assuntos
Nanofibras , Nanofibras/química , Engenharia Tecidual , Preparações Farmacêuticas , Polímeros/química , Extratos Vegetais
20.
PLoS One ; 18(5): e0285094, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37155671

RESUMO

Botrytis cinerea causes gray mold disease of strawberry (Fragaria ×ananassa) and is a globally important pathogen that causes fruit rot both in the field and after harvest. Commercial strawberry production involves the use of plastic mulches made from non-degradable polyethylene (PE), with weedmat made from woven PE and soil-biodegradable plastic mulch (BDM) as emerging mulch technologies that may enhance sustainable production. Little is known regarding how these plastic mulches impact splash dispersal of B. cinerea conidia. The objective of this study was to investigate splash dispersal dynamics of B. cinerea when exposed to various plastic mulch surfaces. Mulch surface physical characteristics and conidial splash dispersal patterns were evaluated for the three mulches. Micrographs revealed different surface characteristics that have the potential to influence splash dispersal: PE had a flat, smooth surface, whereas weedmat had large ridges and BDM had an embossed surface. Both PE mulch and BDM were impermeable to water whereas weedmat was semi-permeable. Results generated using an enclosed rain simulator system showed that as the horizontal distance from the inoculum source increased, the number of splash dispersed B. cinerea conidia captured per plate decreased for all mulch treatments. More than 50% and approximately 80% of the total number of dispersed conidia were found on plates 10 and 16 cm away from the inoculum source across all treatments, respectively. A significant correlation between the total and germinated conidia on plates across all mulch treatments was detected (P<0.01). Irrespective of distance from the inoculum source, embossed BDM facilitated higher total and germinated splashed conidia (P<0.001) compared to PE mulch and weedmat (P = 0.43 and P = 0.23, respectively), indicating BDM's or embossed film's potential for enhancing B. cinerea inoculum availability in strawberry production under plasticulture. However, differences in conidial concentrations observed among treatments were low and may not be pathologically relevant.


Assuntos
Plásticos Biodegradáveis , Fragaria , Solo , Esporos Fúngicos , Microbiologia do Solo , Botrytis , Polietileno
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