ABSTRACT
The field of fluorescence sensing, leveraging various supramolecular self-assembled architectures constructed from macrocyclic pillar[n]arenes, has seen significant advancement in recent decades. This review comprehensively discusses, for the first time, the recent innovations in the synthesis and self-assembly of pillar[n]arene-based supramolecular architectures (PSAs) containing metal coordination sites, along with their practical applications and prospects in fluorescence sensing. Integrating hydrophobic and electron-rich cavities of pillar[n]arenes into these supramolecular structures endows the entire system with self-assembly behavior and stimulus responsiveness. Employing the host-guest interaction strategy and complementary coordination forces, PSAs exhibiting both intelligent and controllable properties are successfully constructed. This provides a broad horizon for advancing fluorescence sensors capable of detecting environmental pollutants. This review aims to establish a solid foundation for the future development of fluorescence sensing applications utilizing PSAs. Additionally, current challenges and future perspectives in this field are discussed.
ABSTRACT
Antimicrobial peptides (AMPs) exhibit mighty antibacterial properties without inducing drug resistance. Achieving much higher selectivity of AMPs towards bacteria and normal cells has always been a continuous goal to be pursued. Herein, a series of sulfonium-based polypeptides with different degrees of branching and polymerization were synthesized by mimicking the structure of vitamin U. The polypeptide, G2 -PM-1H+ , shows both potent antibacterial activity and the highest selectivity index of 16000 among the reported AMPs or peptoids (e.g., the known index of 9600 for recorded peptoid in "Angew. Chem. Int. Ed., 2020, 59, 6412."), which can be attributed to the high positive charge density of sulfonium and the regulation of hydrophobic chains in the structure. The antibacterial mechanisms of G2 -PM-1H+ are primarily ascribed to the interaction with the membrane, production of reactive oxygen species (ROS), and disfunction of ribosomes. Meanwhile, altering the degree of alkylation leads to selective antibacteria against either gram-positive or gram-negative bacteria in a mixed-bacteria model. Additionally, both in vitro and in vivo experiments demonstrated that G2 -PM-1H+ exhibited superior efficacy against methicillin-resistant Staphylococcus aureus (MRSA) compared to vancomycin. Together, these results show that G2 -PM-1H+ possesses high biocompatibility and is a potential pharmaceutical candidate in combating bacteria significantly threatening human health.
Subject(s)
Methicillin-Resistant Staphylococcus aureus , Peptoids , Vitamin U , Humans , Vitamin U/pharmacology , Peptides/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Vancomycin/pharmacology , Peptoids/chemistry , Bacteria , Antimicrobial Peptides , Microbial Sensitivity TestsABSTRACT
The formation of biofilm and thrombus on medical catheters poses a significant life-threatening concern. Hydrophilic anti-biofouling coatings upon catheter surfaces with complex shapes and narrow lumens are demonstrated to have the potential in reducing complications. However, their effectiveness is constrained by poor mechanical stability and weak substrate adhesion. Herein, a novel zwitterionic polyurethane (SUPU) with strong mechanical stability and long-term anti-biofouling is developed by controlling the ratio of sulfobetaine-diol and ureido-pyrimidinone. Once immersed in water, as-synthesized zwitterionic coating (SUPU3 SE) would undergo a water-driven segment reorientation to obtain much higher durability than its direct drying one, even under various extreme treatments, including acidic solution, abrasion, ultrasonication, flushing, and shearing, in PBS at 37 °C for 14 days. Moreover, SUPU3 SE coating could achieve a 97.1% of exceptional reducing protein fouling, complete prevention of cell adhesion, and long-lasting anti-biofilm performance even after 30 days. Finally, the good anti-thrombogenic formations of SUPU3 SE coating with bacterial treatment are validated in blood circulation through an ex vivo rabbit arteriovenous shunt model. This work provides a facile approach to fabricating stable hydrophilic coating through a simple solvent exchange to reduce thrombosis and infection of biomedical catheters.
Subject(s)
Bacterial Adhesion , Polyurethanes , Animals , Rabbits , Water , Solvents , CathetersABSTRACT
Assisted reproductive technologies (ART), including in vitro fertilization-embryo transfer (IVF-ET) and intracytoplasmic sperm injection (ICSI), are known to contribute a higher risk of birth defects; however, studies have rarely evaluated the association between IVF-ET and diagnostic hearing loss (HL). This study aimed to evaluate the prevalence of and risk factors for HL and to clarify the association between IVF-ET and HL among twinborn infants. We enrolled 1860 live-born twin neonates born at a hospital in China from January 2017 to December 2020. After multi-step hearing screening, participants were diagnosed with HL by pediatric audiologists at 6 months of age. The prevalence of hearing loss and the adjusted odds ratios (AORs) for specific risk factors were estimated using generalized estimation equation (GEE) models in twin-born infants. Characteristics and prevalence of failure for hearing screening and HL were measured in IVF-ET twin infants. IVF-ET conception and preterm birth conferred a higher risk of hearing loss, with increased adjusted odds ratios (AOR [95% confidence intervals (CI)] IVF-ET: 2.82 [1.17-6.80], P = 0.021; preterm birth: 6.14 [2.30-16.40], P < 0.001) than the control group, respectively. Among the 1860 twin infants, more IVF-ET twins failed in dual-step hearing screening (3.26%) and were diagnosed with hearing loss (2.21%) than those conceived by spontaneous pregnancy. CONCLUSION: IVF-ET conception and premature birth were associated with a higher risk of hearing impairment. Twin infants conceived by IVF-ET tended to fail in hearing screening and be diagnosed with hearing loss. These observations provide a more comprehensive approach for the prevention and management of deafness in twin-born children. WHAT IS KNOWN: ⢠IVF-ET technologies conferred a higher risk of birth defects. WHAT IS NEW: ⢠Premature birth and IVF-ET conception were associated with a higher risk of hearing loss among twin infants. ⢠Twin infants conceived by IVF-ET tended to fail in hearing screening and diagnosed with hearing loss.
Subject(s)
Hearing Loss , Infant, Newborn, Diseases , Pregnancy Complications , Premature Birth , Pregnancy , Female , Child , Infant, Newborn , Male , Infant , Humans , Premature Birth/epidemiology , Pregnancy Outcome , Cohort Studies , Semen , Embryo Transfer/adverse effects , Risk Factors , Sperm Injections, Intracytoplasmic/adverse effects , Infant, Newborn, Diseases/etiology , Hearing Loss/diagnosis , Hearing Loss/epidemiology , Hearing Loss/etiology , Fertilization in Vitro/adverse effects , Retrospective StudiesABSTRACT
BACKGROUND: Peri-hilar cholangiocarcinoma (pCCA) is a unique entity, and radical surgery provides the only chance for cure and long-term survival. But it is still under debate which surgical strategy (i.e., left-sided hepatectomy, LH or right-sided hepatectomy, RH) should be followed and benefitted. METHODS: We performed a systematic review and meta-analysis to analyze the clinical outcomes and prognostic value of LH versus RH for resectable pCCA. This study followed the PRISMA and AMSTAR guidelines. RESULTS: A total of 14 cohort studies include 1072 patients in the meta-analysis. The results showed no statistical difference between the two groups in terms of overall survival (OS) and disease-free survival (DFS). But compared to the LH group, the RH group exhibited more employment of preoperative portal vein embolization (PVE), higher rate of overall complications, post-hepatectomy liver failure (PHLF), and perioperative mortality, while LH was associated with higher frequency of arterial resection/reconstruction, longer operative time, and more postoperative bile leakage. There was no statistical difference between the two groups in terms of preoperative biliary drainage, R0 resection rate, portal vein resection, intraoperative bleeding, and intraoperative blood transfusion rate. CONCLUSIONS: According to our meta-analyses, LH and RH have comparable oncological effects on curative resection for pCCA patients. Although LH is not inferior to RH in DFS and OS, it requires more arterial reconstruction which is technically demanding and should be performed by experienced surgeons in high-volume centers. Selectin of surgical strategy between LH and RH should be based on not only tumor location (Bismuth classification) but also vascular involvement and future liver remnant (FLR).
Subject(s)
Bile Duct Neoplasms , Cholangiocarcinoma , Klatskin Tumor , Humans , Klatskin Tumor/surgery , Hepatectomy/methods , Cholangiocarcinoma/surgery , Portal Vein/surgery , Bile Duct Neoplasms/surgery , Bile Duct Neoplasms/pathology , Bile Ducts, Intrahepatic/pathology , Treatment Outcome , Retrospective StudiesABSTRACT
BACKGROUND: Cardiometabolic multimorbidity (CMM) is becoming increasingly common in patients with hypertension, and it is well established that healthy lifestyle plays a key role in the prevention of hypertension. However, the association between combined lifestyle factors and CMM in patients with hypertension is uncertain. METHODS: This prospective analysis included the data (obtained from the UK biobank) of participants with hypertension who did not have coronary heart disease (CHD), stroke, or diabetes. The outcome was the occurrence of CMM, defined as ≥ 1 disease of CHD, stroke, and diabetes that occurred in participants with hypertension. Four lifestyle factors (smoking, alcohol consumption, diet, and physical activity) were assessed using a weighted healthy lifestyle score, and participants were divided into four groups: the very unhealthy, unhealthy, healthy, and very healthy groups. The flexible parameter Royston-Parmar proportional hazard model was used to estimate hazard ratios (HRs) between lifestyles and CMM, as well as the difference in CMM-free life expectancy. RESULTS: During a median follow-up of 12.2 years, 9812 (18.4%) of the 53,397 hypertensive patients occurred CMM. Compared with the very unhealthy group, the very healthy group had a 41% reduction in the risk for CMM in hypertensive patients and a 32-50% reduction in the risk for specific cardiometabolic diseases such as CHD, stroke, and diabetes. For each lifestyle factor, non-smoking had the greatest protective effect against CMM (HR: 0.64, 95% confidence interval (CI) 0.60-0.68). A lifestyle combining multiple healthy factors extended CMM-free life expectancy (e.g., six years longer at age 45 years for participants in the very healthy group). CONCLUSIONS: Combined healthy lifestyle factors were associated with a lower risk for CMM in hypertensive patients. This suggests that combined healthy lifestyle should be supported to decrease disease burden.
Subject(s)
Diabetes Mellitus , Hypertension , Stroke , Biological Specimen Banks , Diabetes Mellitus/epidemiology , Healthy Lifestyle , Humans , Hypertension/diagnosis , Hypertension/epidemiology , Middle Aged , Multimorbidity , Prospective Studies , Risk Factors , Stroke/epidemiology , United Kingdom/epidemiologyABSTRACT
Ten-eleven translocation (TET) proteins regulate DNA methylation and gene expression by converting 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Although Tet2/Tet3 deficiency has been reported to lead to myeloid cell, B-cell and invariant natural killer T (iNKT) cell malignancy, the effect of TET on regulatory T cells (Tregs) has not been elucidated. We found that Tet2/Tet3 deficiency in Tregs led to lethal hyperproliferation of CD4+Foxp3+ T cells in the spleen and mesenteric lymph nodes after 5 months of age. Additionally, in aged Treg-specific Tet2/Tet3-deficient mice, serum IgG1, IgG3, IgM and IgE levels were markedly elevated. High IL-17 expression was observed in both Foxp3+ and Fopx3- CD4+ T cells, and adoptive transfer of Tet2/Tet3-deficient Tregs into lymphopenic mice inhibited Foxp3 expression and caused conversion into IL-17-producing cells. However, the conserved non-coding DNA sequence-2 (CNS2) region of the Foxp3 gene locus, which has been shown to be particularly important for stable Foxp3 expression, was only partly methylated. We identified novel TET-dependent demethylation sites in the Foxp3 upstream enhancer, which may contribute to stable Foxp3 expression. Together, these data indicate that Tet2 and Tet3 are involved in Treg stability and immune homeostasis in mice.
Subject(s)
DNA-Binding Proteins/immunology , Dioxygenases/immunology , Forkhead Transcription Factors/metabolism , Interleukin-17/biosynthesis , Proto-Oncogene Proteins/immunology , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/pathology , Animals , Cell Proliferation , Interleukin-17/immunology , Mice , Mice, Inbred C57BLABSTRACT
Although the original purpose of the systemic lupus erythematosus (SLE) classification criteria was to distinguish SLE from other mimic diseases, and to facilitate sample selection in scientific research, they have become widely used as diagnostic criteria in clinical situations. It is not known yet if regarding classification criteria as diagnostic criteria, what problems might be encountered? This is the first study comparing the three sets of classification criteria for SLE, the 1997 American College of Rheumatology (ACR'97), 2012 Systemic Lupus International Collaborating Clinics (SLICC'12) and 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR'19), for their ability to distinguish patients with SLE from patients with pure mucocutaneous manifestations (isolated cutaneous lupus erythematosus without internal disease, i-CLE) in the lupus disease spectrum. 1,865 patients with SLE and 232 patients with i-CLE were recruited from a multicenter study. We found that, due to low specificity, none of the three criteria are adept at distinguishing patients with SLE from patients with i-CLE. SLICC'12 performed best among the original three criteria, but if a positive ANA was removed as an entry criterion, EULAR/ACR'19 would performed better. A review of previous studies that compared the three sets of criteria was presented in this work.
Subject(s)
Lupus Erythematosus, Cutaneous/diagnosis , Lupus Erythematosus, Systemic/diagnosis , Adult , Antibodies, Antinuclear/blood , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Rheumatology/methods , Sensitivity and Specificity , Societies, MedicalABSTRACT
In this work, two monomethoxy oligo(ethylene glycol) (OEG)-substituted episulfides are prepared and a series of polysulfides are synthesized with subsequent ring-opening polymerization. The OEGylated polysulfides exhibit thermal and reactive oxygen species (ROS) dual-responsive behavior. Their lower critical solution temperatures (LCSTs) are close to human body temperature and depend on the degree of polymerization and OEG length. Notably, the LCST of the polysulfide increases linearly with the oxidation degree by H2 O2 , showing a highly tunable change regulated by the ratio between hydrophobic sulfide and hydrophilic sulfoxide/sulfone in the backbone. Further, the OEGylated polysulfide can act as a ROS scavenger to protect red blood cells (RBCs) from oxidative damage in an RBCs aging model in vitro. This work paves a facile way to synthesize LCST-tunable polysulfides, which hold great promise in biological applications.
Subject(s)
Polymers , Sulfides , Humans , Reactive Oxygen Species , TemperatureABSTRACT
A versatile platform allowing capture and detection of normal and dysfunctional cells on the same patterned surface is important for accessing the cellular mechanism, developing diagnostic assays, and implementing therapy. Here, an original and effective method for fabricating binary polymer brushes pattern is developed for controlled cell adhesion. The binary polymer brushes pattern, composed of poly(N-isopropylacrylamide) (PNIPAAm) and poly[poly(ethylene glycol) methyl ether methacrylate] (POEGMA) chains, is simply obtained via a combination of surface-initiated photopolymerization and surface-activated free radical polymerization. This method is unique in that it does not utilize any protecting groups or procedures of backfilling with immobilized initiator. It is demonstrated that the precise and well-defined binary polymer patterns with high resolution are fabricated using this facile method. PNIPAAm chains capture and release cells by thermoresponsiveness, while POEGMA chains possess high capability to capture dysfunctional cells specifically, inducing a switch of normal red blood cells (RBCs) arrays to hemolytic RBCs arrays on the pattern with temperature. This novel platform composed of binary polymer brush pattern is smart and versatile, which opens up pathways to potential applications as microsensors, biochips, and bioassays.
Subject(s)
Polymers/chemistry , Acrylic Resins/adverse effects , Acrylic Resins/chemistry , Acrylic Resins/pharmacology , Cell Adhesion/drug effects , Erythrocytes/drug effects , Hemolysis/drug effects , Humans , Methacrylates/adverse effects , Methacrylates/chemistry , Methacrylates/pharmacology , Microscopy, Electron, Scanning , Polyethylene Glycols/adverse effects , Polyethylene Glycols/chemistry , Polyethylene Glycols/pharmacology , Polymers/adverse effects , Polymers/pharmacology , Surface Properties , TemperatureABSTRACT
Keratoderma-hypotrichosis-leukonychia totalis syndrome (KHLS) is an extremely rare, autosomal-dominant disorder characterized by severe skin hyperkeratosis, congenital alopecia and leukonychia totalis. The genetic defect underlying KHLS remained undetermined. By performing whole-exome sequencing in a family with KHLS, we identified a heterozygous mutation (c.23G>T [p.Gly8Val]) in GJA1, which cosegregated with the phenotype in the family. In an additional affected individual, we also found the identical de novo mutation which was absent in his unaffected family members. GJA1 encodes a gap junction protein connexin 43 (Cx43) which is ubiquitously expressed in various organs, including the epidermis and hair follicles. In vitro studies on HEK293 cells expressing Cx43(Gly8Val) found that the protein formed gap junction plaques between adjacent transfected cells, as observed in the wild-type. Dye-transfer experiments by microinjection of Lucifer yellow displayed functional gap junction of the Cx43(Gly8Val) mutant. Using patch clamp and Ca(2+) imaging methods, we observed that the Cx43(Gly8Val) hemichannel had significantly more openings than Cx43(WT), facilitating Ca(2+) influx at resting potential. Such gain-of-function effect might result in cytoplasmic Ca(2+) overload, accelerated apoptosis of keratinocytes and subsequent skin hyperkeratosis. Taken together, our results demonstrated that, with probably enhanced hemichannel activities, a mutation in GJA1 is linked to KHLS without extracutaneous involvement.
Subject(s)
Calcium/metabolism , Connexin 43/genetics , Connexin 43/metabolism , Hypotrichosis/genetics , Hypotrichosis/pathology , Keratoderma, Palmoplantar/genetics , Keratoderma, Palmoplantar/pathology , Nail Diseases/genetics , Nail Diseases/pathology , Pigmentation Disorders/genetics , Pigmentation Disorders/pathology , Adult , Child, Preschool , Epidermis/metabolism , Exome , Female , Genetic Predisposition to Disease , HEK293 Cells , Hair Follicle/metabolism , Heterozygote , High-Throughput Nucleotide Sequencing , Humans , Hypotrichosis/metabolism , Keratoderma, Palmoplantar/metabolism , Male , Mutation, Missense , Nail Diseases/metabolism , Pedigree , Pigmentation Disorders/metabolism , Sequence Analysis, DNAABSTRACT
Basic leucine zipper transcription factor E4BP4 (also known as NFIL3) has been implicated in the molecular and cellular mechanisms of functions and activities in mammals. The interactions between E4BP4 and major regulators of cellular processes have triggered significant interest in the roles of E4BP4 in the pathogenesis of certain chronic diseases. Indeed, novel discoveries have been emerging to illustrate the involvement of E4BP4 in multiple disorders. It is recognized that E4BP4 is extensively involved in some immune-mediated diseases, but the mechanisms of E4BP4 involvement in these complex diseases remain poorly defined. Here we review the regulatory mechanisms of E4BP4 engaging in not only the biological function but also the development of immune-mediated diseases, paving the way for future therapies.
Subject(s)
Basic-Leucine Zipper Transcription Factors/immunology , Animals , Humans , Immune System , Immune System Diseases/immunologyABSTRACT
Quartz crystal microbalance with dissipation (QCM-D) and dual polarization interferometry (DPI) were used to investigate fibrinogen (Fib) adsorption behavior on different surfaces by changing the pH value. Moreover, integrin adhesion to the adsorbed Fibs was studied using DPI. Qualitative and quantitative studies of platelet adhesion to the adsorbed Fibs were performed using scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), and released lactate dehydrogenase (LDH) assay. Experimental results indicated that the conformation and orientation of the absorbed Fibs depended on surface property and pH cycling. For the hydrophilic surface, Fibs adsorbed at pH 7.4 and presented a αC-hidden orientation. As a result, no integrin adhesion was observed, and a small number of platelets were adhered because the αC-domains were hidden under the Fib molecule. By changing the rinsing solution pH from 7.4 to 3.2 and then back to 7.4, the adsorbed Fib orientation became αC-exposed via the transformation of Fib conformation during pH cycling. Therefore, integrin adhesion was more likely to occur, and more platelets were adhered and activated. For the hydrophobic surface, the adsorbed Fibs became more spread and stretched due to the strong interaction between the Fibs and surface. αC-exposed orientation remained unchanged when the rinsing solution pH changed from 7.4 to 3.2 and then back to 7.4. Therefore, a large number of integrins and platelets were adhered to the adsorbed Fibs, and almost all of the adhered platelets were activated.
Subject(s)
Fibrinogen/chemistry , Fibrinogen/pharmacology , Platelet Adhesiveness/drug effects , Adsorption , Animals , Cattle , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Integrins/metabolism , Protein Conformation , Surface PropertiesABSTRACT
Although polycationic surfaces have high antimicrobial efficacies, they suffer from high toxicity to mammalian cells and severe surface accumulation of dead bacteria. For the first time, we propose a surface-initiated photoiniferter-mediated polymerization (SI-PIMP) strategy of constructing a "cleaning" zwitterionic outer layer on a polycationic bactericidal background layer to physically hinder the availability of polycationic moieties for mammalian cells in aqueous service. In dry conditions, the polycationic layer exerts the contact-active bactericidal property toward the adherent bacteria, as the zwitterionic layer collapses. In aqueous environment, the zwitterionic layer forms a hydration layer to significantly inhibit the attachment of planktonic bacteria and the accumulation of dead bacteria, while the polycationic layer kills bacteria occasionally deposited on the surface, thus preserving the antibacterial capability for a long period. More importantly, the zwitterionic hydrated layer protects the mammalian cells from toxicity induced by the bactericidal background layer, and therefore hierarchical antibacterial surfaces present much better biocompatibility than that of the naked cationic references. The dominant antibacterial mechanism of the hierarchical surfaces can switch from the bactericidal efficacy in dry storage to the bacteria repellent capability in aqueous service, showing great advantages in the infection-resistant applications.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Bacterial Infections/drug therapy , Fibroblasts/drug effects , Polymers/chemistry , Animals , Anti-Bacterial Agents/chemistry , Bacteria/growth & development , Bacterial Adhesion , Bacterial Infections/microbiology , Cells, Cultured , Coated Materials, Biocompatible , Fibroblasts/cytology , Mice , Polymerization , Surface PropertiesABSTRACT
Pure hair and nail ectodermal dysplasia (PHNED) is a congenital condition characterized by hypotrichosis and nail dystrophy. Autosomal-recessive PHNED has previously been mapped to chromosomal region 12q12-q14.1, which contains the type II hair keratin and HOXC clusters. Hoxc13-null mice are known to develop hair and nail defects very similar to those seen in human PHNED. We performed whole-exome sequencing in a consanguineous Chinese family affected by PHNED and identified a homozygous nonsense mutation (c.390C>A [p.Tyr130(∗)]) in HOXC13 in all affected individuals. In an additional affected female from a consanguineous Afghan family, we found a 27.6 kb homozygous microdeletion involving the first exon of HOXC13. We examined HOXC13 expression in scalp specimen obtained from the index individual of the Chinese family and detected dramatically reduced mRNA levels in skin tissue and nearly absent protein staining in hair follicles, suggesting a mechanism of nonsense-mediated mRNA decay. We also observed markedly decreased expression of four HOXC13 target genes in the specimen. Taken together, our results demonstrate that loss-of-function mutations in HOXC13 cause autosomal-recessive PHNED and further highlight the importance of HOXC13 in hair and nail development.
Subject(s)
Ectodermal Dysplasia/genetics , Homeodomain Proteins/genetics , Hypotrichosis/genetics , Nail Diseases/genetics , Animals , Asian People/genetics , China , Consanguinity , Ectodermal Dysplasia/pathology , Exome , Female , Gene Expression Profiling , Gene Expression Regulation , Genes, Recessive , Homozygote , Humans , Male , Mice , Mice, Transgenic , Pedigree , Phenotype , Skin/pathologyABSTRACT
The measurement speed is an important parameter of terahertz time-domain spectroscopy (THz-TDS) instruments. To improve the measurement speed of the spectrometer we need to increase the scanning speed of the delay line. In this paper, we study the influence of the scanning speed, the time constant of lock-in amplifier and the sampling rate on the signal quality. The results show that, when the time constant equal to 10 ms, increasing the scanning speed does not cause significant changes in the amplitude of the signal. But when the time constant equal to 30, 100 and 300 ms, with the increasing of the scanning speed the signal amplitude decreases rapidly. Therefore, the time constant should be set as small as possible to avoid deterioration of signal quality. On the other hand, higher the scanning speed is, fewer data points are collected with a same time-domain length. Therefore, when the scanning speed increase, not only the time constant should be reduced, but also the sampling rate should be increased to avoid the distortion of signal waveform caused by the number reduction of data points. The conclusions can provide a reference for improving the measurement speed of THz-TDS instrument.
ABSTRACT
Despite the importance of adhesion between electrospun meshes and substrates, the knowledge on adhesion mechanism and the method to improve the adhesion remain limited. Here, we precisely design the model system based on electrospun poly(ethylene oxide) (PEO) meshes and the substrate of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS), and quantitatively measure the adhesion with a weight method. The surfaces of SEBS with different roughness are obtained by casting SEBS solution on the smooth and rough glass slides, respectively. Then, the surfaces of casted SEBS are respectively grafted with PEG oligomers and long PEG chains much larger than the entanglement molecular weight by surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA). The detached surfaces of SEBS and electrospun fibers after adhesion measurements are analyzed by scanning electron microscopy (SEM). The adhesive force and adhesion energy are found to lie in the range from 68 to 220 mN and from 12 to 46 mJ/m(2), respectively, which are slightly affected by surface roughness of substrate but mainly determined by surface interactions. Just as the chemical cross-linking induces the strong adhesion, the chain entanglements on the interface lead to the higher adhesion than those generated by hydrophilic-hydrophobic interactions and hydrophilic interactions. The long grafted chains and the enhanced temperature facilitate the chain entanglements, resulting in the strong adhesive force. This work sheds new light on the adhesion mechanism at molecular level, which may be helpful to improve the adhesion between the electrospun fibers and substrates in an environmentally friendly manner.
ABSTRACT
Enhancing the high electric field resistance and energy storage capacity of polymer dielectrics has been a long-standing challenge for the iterations of power equipment. Synergistic inhibition of carrier injection and transport is vital to energy storage performance improvement. Herein, promising polymer polyetherimide (PEI) was employed as a matrix and wider bandgap boron nitride nanosheets (BNNSs) were used as a reinforcing filler. Utilizing high-throughput stochastic breakdown simulations with the distribution characteristics of BNNSs as parameters, a series of topological gradient structures with the potential to enhance performance were obtained, thereby shortening the experimental cycle. Changing the BNNS distribution of symmetric/asymmetric and positive/inverse gradients, as well as the total and gradient contents of BNNSs, means that the position and condition of the surface barrier layer and central hinder layer change, which influences the energy storage performance of the polymer at room temperature and high temperature. Remarkably, the asymmetric gradient structure composite dielectrics exhibited excellent performances. Among them, the PEI-based composite dielectric with 2 vol% BNNS asymmetric inverse gradient distribution (gradient content of 1 vol%) achieved energy densities of 8.26 and 4.78 J cm-3 at room temperature and 150 °C, respectively. The asymmetric gradient structure design strategy holds great promise for optimizing the energy storage capacity of polymer dielectric capacitors.
ABSTRACT
Bacteria-associated infections and thrombosis, particularly catheter-related bloodstream infections and catheter-related thrombosis, are life-threatening complications. Herein, we utilize a concise assembly of heparin sodium with organosilicon quaternary ammonium surfactant to fabricate a multifunctional coating complex. In contrast to conventional one-time coatings, the complex attaches to medical devices with arbitrary shapes and compositions through a facile dipping process and further forms robust coatings to treat catheter-related bloodstream infections and thrombosis simultaneously. Through their robustness and adaptively dissociation, coatings not only exhibit good stability under extreme conditions but also significantly reduce thrombus adhesion by 60%, and shows broad-spectrum antibacterial activity ( > 97%) in vitro and in vivo. Furthermore, an ex vivo rabbit model verifies that the coated catheter has the potential to prevent catheter-related bacteremia during implantation. This substrate-independent and portable long-lasting multifunctional coating can be employed to meet the increasing clinical demands for combating catheter-related bloodstream infections and thrombosis.
Subject(s)
Bacteremia , Bacterial Infections , Thrombosis , Animals , Rabbits , Heparin/pharmacology , Catheters/microbiology , Anti-Bacterial Agents/pharmacology , Thrombosis/drug therapy , Thrombosis/prevention & controlABSTRACT
Protein adsorption has a vital role in biomaterial surface science because it is directly related to the hemocompatibility of blood-contacting materials. In this study, monomethoxy poly(ethylene glycol) (mPEG) with two different molecular weights was grafted on polyethylene as a model to elucidate the adsorption mechanisms of plasma protein through quartz crystal microbalance with dissipation (QCM-D). Combined with data from platelet adhesion, whole blood clotting time, and hemolysis rate, the blood compatibility of PE-g-mPEG film was found to have significantly improved. Two adsorption schemes were developed for real-time monitoring of protein adsorption. Results showed that the preadsorbed bovine serum albumin (BSA) on the surfaces of PE-g-mPEG films could effectively inhibit subsequent adsorption of fibrinogen (Fib). Nonspecific protein adsorption of BSA was determined by surface coverage, not by the chain length of PEG. Dense PEG brush could release more trapped water molecules to resist BSA adsorption. Moreover, the preadsorbed Fib could be gradually displaced by high-concentration BSA. However, the adsorption and displacement of Fib was determined by surface hydrophilicity.