Comparison of the clinical outcomes between proximal femoral nail anti-rotation with cement enhancement and hemiarthroplasty among elderly osteoporotic patients with intertrochanteric fracture.

BACKGROUND: The proximal femoral nail anti-rotation (PFNA) with cement enhancement enhances the anchorage ability of internal fixation in elderly with osteoporotic intertrochanteric fracture. However, whether it is superior to hemiarthroplasty is still controversial. The present study aimed to determine which treatment has better clinical outcomes among older patients. METHODS: We retrospectively analyzed 102 elderly patients with osteoporosis who developed intertrochanteric fractures and underwent PFNA combined with cement-enhanced internal fixation (n = 52, CE group), and hemiarthroplasty (n = 50, HA group) from September 2012 to October 2018. All the intertrochanteric fractures were classified according to the AO/OTA classification. Additionally, the operative time, intraoperative blood loss, intraoperative and postoperative blood transfusion rates, postoperative weight-bearing time, hospitalization time, Barthel Index of Activities Daily Living, Harris score of hip function, visual analog (VAS) pain score, and postoperative complications were compared between the two groups. RESULTS: The CE group had significantly shorter operative time, lesser intraoperative blood loss, lower blood transfusion rate, and longer postoperative weight-bearing time than the HA group. The CE group had lower Barthel's Index of Activities of Daily Living, lower Harris' score, and higher VAS scores in the first and third months after surgery than the HA group, but no difference was observed between the two groups from 6 months to 12 months. There was no significant difference in the total post-operative complications between the two groups. CONCLUSION: The use of PFNA combined with a cement-enhanced internal fixation technique led to shorter operative time and lesser intraoperative blood loss and trauma in elderly patients as compared to HA.

Programming colloidal bonding using DNA strand-displacement circuitry.

As a strategy for regulating entropy, thermal annealing is a commonly adopted approach for controlling dynamic pathways in colloid assembly. By coupling DNA strand-displacement circuits with DNA-functionalized colloid assembly, we developed an enthalpy-mediated strategy for achieving the same goal while working at a constant temperature. Using this tractable approach allows colloidal bonding to be programmed for synchronization with colloid assembly, thereby realizing the optimal programmability of DNA-functionalized colloids. We applied this strategy to conditionally activate colloid assembly and dynamically switch colloid identities by reconfiguring DNA molecular architectures, thereby achieving orderly structural transformations; leveraging the advantage of room-temperature assembly, we used this method to prepare a lattice of temperature-sensitive proteins and gold nanoparticles. This approach bridges two subfields: dynamic DNA nanotechnology and DNA-functionalized colloid programming.

The Sequence Characteristics and Binding Properties of the Odorant-Binding Protein 2 of Euplatypus parallelus to Semiochemicals.

Euplatypus parallelus is one of the dominant rubber bark beetle species in Hainan's rubber-planting area. Semiochemicals, including the volatiles found in rubber trees and aggregation pheromones, play an important role in the search for suitable host plants. To examine the possible functional role of highly expressed odorant-binding protein 2 of Euplatypus parallelus (EparOBP2) in the semiochemical recognition process, we cloned and analyzed the cDNA sequence of EparOBP2. The results showed that EparOBP2 contains an open reading frame (ORF) of 393 bp that encodes 130 amino acids, including a 21-amino-acid residue signal peptide at the N-terminus. The matured EparOBP2 protein consists of seven α-helices, creating an open binding pocket and three disulfide bridges. The results of the fluorescence binding assay showed that EparOBP2 had high binding ability with α-pinene and myrcene. The docking results confirmed that the interactions of α-pinene and myrcene with EparOBP2 were primarily achieved through hydrophobic interactions. This study provides evidence that EparOBP2 may be involved in the chemoreception of semiochemicals and that it can successfully contribute to the integrated management of E. parallelus.

[Preparation and in vitro property evaluation of ß-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocrystals].

This study aims to improve the solubility and bioavailability of daidzein by preparing the ß-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocrystals. Specifically, the nanocrystals were prepared with daidzein as a model drug, PEG_(20000), Carbomer_(940), and NaOH as a plasticizer, a gelling agent, and a crosslinking agent, respectively. A two-step method was employed to prepare the ß-cyclodextrin-daidzein/PEG_(20000)/Carbomer_(940) nanocystals. First, the insoluble drug daidzein was embedded in ß-cyclodextrin to form inclusion complexes, which were then encapsulated in the PEG_(20000)/Carbomer_(940) nanocrystals. The optimal mass fraction of NaOH was determined as 0.8% by the drug release rate, redispersability, SEM morphology, encapsulation rate, and drug loading. The inclusion status of daidzein nanocrystals was determined by Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TGA), and X-ray diffraction(XRD) analysis to verify the feasibility of the preparation. The prepared nanocrystals showed the average Zeta potential of(-30.77±0.15)mV and(-37.47±0.64)mV and the particle sizes of(333.60±3.81)nm and(544.60±7.66)nm before and after daidzein loading, respectively. The irregular distribution of nanocrystals before and after daidzein loading was observed under SEM. The redispersability experiment showed high dispersion efficiency of the nanocrystals. The in vitro dissolution rate of nanocrystals in intestinal fluid was significantly faster than that of daidzein, and followed the first-order drug release kinetic model. XRD, FTIR, and TGA were employed to determine the polycrystalline properties, drug loading, and thermal stability of the nanocrystals before and after drug loading. The nanocrystals loaded with daidzein demonstrated obvious antibacterial effect. The nanocrystals had more significant inhibitory effects on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa than daidzein because of the improved solubility of daidzein. The prepared nanocrystals can significantly increase the dissolution rate and oral bioavailability of the insoluble drug daidzein.

Experimental Analysis of In Situ Fenestration of Endovascular Stent-Grafts: Comparison between Needle and Laser Puncture.

BACKGROUND: To evaluate the quality of in vitro fenestrations during in situ fenestration (ISF) and investigate the differences between needle and laser puncture in current stent-grafts. METHODS: An in vitro study evaluated the damage created by needle ISF on stent-graft fabrics versus laser ISF. Fenestrations were made in 5 different commercially available stent-grafts, including polyester stent-grafts (Relay, Valiant and Hercules) and expanded polytetrafluoroethylene (ePTFE) stent-grafts (TAG and Ankura). Each stent-graft received fenestration by needle and laser separately, followed by gradual dilation (4 mm, 6 mm, 8 mm, and 10 mm sequentially) of noncompliant balloons. Quantitative and qualitative evaluations including fenestration diameter, area, shape and margins were conducted using light microscopy and scanning electron microscope. RESULTS: The primary fenestrations created by needle were slit-like with visible cut-off fibers in polyester stent-grafts and were almost circular with clear margins in ePTFE stent-grafts; those created by laser were squared or elliptical with ragged edges and burned fibers in all the stent-grafts. Fabric debris and toxic particles due to burning of the material were generated during laser-assisted fenestration. The Primary holes in polyester stent-grafts (Relay, Valiant and Hercules) by needle showed smaller area (0.05 mm2 vs. 0.22 mm2, 0.52 mm2 vs. 0.70 mm2 and 0.28 mm2 vs. 0.46 mm2; P < 0.01) and worse shape (0.93 vs. 2.46, 1.17 vs. 2.33 and 0.93 vs. 2.47; P < 0.01) than those by laser, while larger area (0.67 vs.0.43, 0.59 vs.0.45; P < 0.05), better shape (3.93 vs. 2.53, 3.90 vs. 2.93; P < 0.05) and better margin (3.83 vs. 2.47, 3.83 vs. 2.53; P < 0.05) in ePTFE stent-grafts (TAG and Ankrura). After gradual balloon dilation, the final holes showed no evident difference in maximal length, fenestration area, scores of shape and margin between the 2 ways of fenestration (P > 0.05). Ankura stent-graft showed the largest holes with best quality than the others. CONCLUSIONS: The primary fenestrations were different between needle and laser puncture, laser induced fabric debris and toxic particles release should be cautiously considered. The final fenestrations were similar after gradual balloon dilation.

[Research progress of dummy template molecularly imprinted polymers in separation of natural products].

The dummy template molecularly imprinted polymers not only has such characteristics of normal imprinted polymers as rapid identification, easy preparation, stable structure and multiple reuse, but also can imprint the compounds in natural products that are not suitable as direct template. Therefore, it has drawn more and more attention in the field of the study of natural products. This paper summarizes the methods for the selection of dummy template molecules by investigating the relevant literatures in the past ten years, analyzes the advantages and disadvantages of dummy template molecules in the practical application, and based on the types of natural products active ingredients, this paper is the first to review of the latest progress in extraction and separation of dummy template molecularly imprinted polymers. We believed that this paper could provide references for better applications of the dummy template molecularly imprinted polymers to extract and separate natural products.

[Molecular imprinting technology and its application in terpenoids].

Molecular imprinting technology is widely used in the separation and analysis of compounds such as flavonoids, alkaloids and polyphenols, due to its high selectivity and specific recognition and so on. However, no much of attention has been paid to the terpenoids. This paper is aimed to not only review the effects of common synthetic elements such as functional monomers, cross-linking agents and porogens on the polymer properties, but also highlight the application of terpene molecular imprinting in solid phase extraction, sensor, membrane separation and chromatographic separation by means of statistical analysis of literature. Furthermore, the shortcomings and improvement directions are discussed.We believed that this paper could provide references for better applications of molecular imprinting techniques to the analysis of terpenoid compounds.

Aliidongia dinghuensis gen. nov., sp. nov., a poly-ß-hydroxybutyrate-producing bacterium isolated from Pinus massoniana forest soil.

A Gram-stain-negative, aerobic, motile, rod-shaped bacterium, designated 7M-Z19T, was isolated from a soil sample collected from a Pinus massoniana forest of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain 7M-Z19T grew at pH 4.5-7.5 (optimum pH 6.0-6.5), 10 to 37 °C (optimum 28 °C) and NaCl concentration up to 2.0 % (optimum 0 %, w/v). iso-C17 : 0, C18 : 1ω7c and C19 : 0ω8c cyclo were the major fatty acids (>10 %) while ubiquinone-10 was the only respiratory quinone detected in 7M-Z19T. The polar lipids of the strain consisted of phosphatidylethanolamine, phosphatidyldimethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, six unidentified aminophospholipids, three unidentified phospholipids, six unidentified lipids and a glycolipid. The DNA G+C content was 65.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate formed a distinct lineage with Dongia mobilis and Dongia rigui within the family Rhodospirillaceae, but with a low sequence similarity of 92.7 and 92.0 %, respectively. On the basis of phylogenetic, phenotypic, physiological and chemotaxonomic distinctiveness, strain 7M-Z19T should be placed in the family Rhodospirillaceae as a representative of a novel genus and species, for which the name Aliidongia dinghuensis gen. nov., sp. nov., is proposed. The type strain of the type species is 7M-Z19T (=NBRC 112240T=KCTC 52134T=CGMCC 1.15725T).

Screening and Functional Analyses of Nilaparvata lugens Salivary Proteome.

Most phloem-feeding insects secrete gelling and watery saliva during the feeding process. However, the functions of salivary proteins are poorly understood. In this study, our purpose was to reveal the components and functions of saliva in a rice sap-sucking insect pest, Nilaparvata lugens. The accomplishment of the whole genome and transcriptome sequencing in N. lugens would be helpful for elucidating the gene information and expression specificity of the salivary proteins. In this study, we have, for the first time, identified the abundant protein components from gelling and watery saliva in a monophagous sap-sucking insect species through shotgun proteomic detection combined with the genomic and transcriptomic analysis. Eight unknown secreted proteins were limited to N. lugens, indicating species-specific saliva components. A group of annexin-like proteins first identified in the secreted saliva displayed different domain structure and expression specificity with typical insect annexins. Nineteen genes encoding five annexin-like proteins, six salivaps (salivary glands-specific proteins with unknown function), seven putative enzymes, and a mucin-like protein showed salivary gland-specific expression pattern, suggesting their importance in the physiological mechanisms of salivary gland and saliva in this insect species. RNA interference revealed that salivap-3 is a key protein factor in forming the salivary sheath, while annexin-like5 and carbonic anhydrase are indispensable for N. lugens survival. These novel findings will greatly help to clarify the detailed functions of salivary proteins in the physiological process of N. lugens and elucidate the interaction mechanisms between N. lugens and the rice plant, which could provide important targets for the future management of rice pests.

DNA Polymer Brush Patterning through Photocontrollable Surface-Initiated DNA Hybridization Chain Reaction.

The fabrication of DNA polymer brushes with spatial resolution onto a solid surface is a crucial step for biochip research and related applications, cell-free gene expression study, and even artificial cell fabrication. Here, for the first time, a DNA polymer brush patterning method is reported based on the photoactivation of an ortho-nitrobenzyl linker-embedded DNA hairpin structure and a subsequent surface-initiated DNA hybridization chain reaction (HCR). Inert DNA hairpins are exposed to ultraviolet light irradiation to generate DNA duplexes with two active sticky ends (toeholds) in a programmable manner. These activated DNA duplexes can initiate DNA HCR to generate multifunctional patterned DNA polymer brushes with complex geometrical shapes. Different multifunctional DNA polymer brush patterns can be fabricated on certain areas of the same solid surface using this method. Moreover, the patterned DNA brush surface can be used to capture target molecules in a desired manner.

DTR-Net: Dual-Space 3D Tooth Model Reconstruction From Panoramic X-Ray Images.

In digital dentistry, cone-beam computed tomography (CBCT) can provide complete 3D tooth models, yet suffers from a long concern of requiring excessive radiation dose and higher expense. Therefore, 3D tooth model reconstruction from 2D panoramic X-ray image is more cost-effective, and has attracted great interest in clinical applications. In this paper, we propose a novel dual-space framework, namely DTR-Net, to reconstruct 3D tooth model from 2D panoramic X-ray images in both image and geometric spaces. Specifically, in the image space, we apply a 2D-to-3D generative model to recover intensities of CBCT image, guided by a task-oriented tooth segmentation network in a collaborative training manner. Meanwhile, in the geometric space, we benefit from an implicit function network in the continuous space, learning using points to capture complicated tooth shapes with geometric properties. Experimental results demonstrate that our proposed DTR-Net achieves state-of-the-art performance both quantitatively and qualitatively in 3D tooth model reconstruction, indicating its potential application in dental practice.

Hydrangeaxinfeniae (Hydrangeaceae), a new species from Sichuan, China.

Hydrangeaxinfeniae W.B.Ju & J.Ru, a new species of Hydrangeaceae from Sichuan Province, China, is described and illustrated. The new species belongs to Hydrangeasect.Dichroa (Lour.) Y.De Smet & Samain, with its distinctive characteristic being the nearly superior ovary. It shares morphological similarities with H.yaoshanensis (Y.C.Wu) Y.De Smet & C.Granados, but can be distinguished by its hirsute trichomes densely covered on the branchlets, leaves, peduncles and pedicels, broadly elliptic to rectangular-elliptic leaf blade with nearly rounded base, coarse teeth leaf margins, 3-4 pairs of lateral veins, corymbose cyme with few and loose branches, lanceolate bract, the calyx tube and lobes margin with sparsely hirsute trichomes, adaxially glabrous and abaxially sparsely hirsute petal, outer whorl filaments are linear, inner ones are awl-shaped, glabrous styles, and the nearly superior ovary. H.xinfeniaesp. nov. currently known from only three relatively small populations of the type locality, and its conservation status is assessed as Data Deficient (DD).

A biomimetic nanocarrier facilitates glucose consumption and reactive oxide species accumulation in enzyme therapy for colorectal cancer.

Glucose oxidase (GOx)-based enzyme therapeutics are potential alternatives for colorectal cancer (CRC) treatment via glucose consumption and accumulation of hydrogen peroxide (H2O2). Given that H2O2 can be eliminated by cytoprotective autophagy, autophagy inhibitors that can interrupt autolysosome-induced H2O2 elimination are promising combination drugs of GOx. Here, we developed a multifunctional biomimetic nanocarrier for effective co-delivery of an autophagy inhibitor-chloroquine phosphate (CQP) and GOx to exert their synergistic effect by irreversibly upregulating intracellular reactive oxygen species (ROS) levels. Poly (D, l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) were used to encapsulate both GOx and CQP using a W/O/W multi-emulsion method. Calcium phosphate (CaP) was used to "fix" CQP to GOx in the internal water phase, where it served as a pH-sensitive unit to facilitate intracellular drug release. Folic acid-modified red blood cell membranes (FR) were used to camouflage the GOx/CQP/CaP encapsulated PLGA NPs (referred to as PLGA/GCC@FR). In an AOM/DSS-induced CRC mouse model, PLGA/GCC@FR exhibited improved antitumor effects, in which the number of tumor nodes were only a quarter of that in the free drug combination group. The enhanced therapeutic effects of PLGA/GCC@FR were attributed to the prolonged tumor retention which was verified by both dynamic in vivo imaging and drug biodistribution. This multifunctional biomimetic nanocarrier facilitated combined enzyme therapeutics by depleting glucose and augmenting intracellular ROS levels in tumor cells, which exerted a synergistic inhibitory effect on tumor growth. Therefore, this study proposed a novel strategy for the enhancement of combined enzyme therapeutics, which provided a promising method for effective CRC treatment.

Improvement of Saccharomyces cerevisiae strain tolerance to vanillin through heavy ion radiation combined with adaptive laboratory evolution.

Vanillin is an inhibitor of lignocellulose hydrolysate, which can reduce the ability of Saccharomyces cerevisiae to utilize lignocellulose, which is an important factor limiting the development of the ethanol fermentation industry. In this study, mutants of vanillin-tolerant yeast named H6, H7, X3, and X8 were bred by heavy ion irradiation (HIR) combined with adaptive laboratory evolution (ALE). Phenotypic tests revealed that the mutants outperformed the original strain WT in tolerance, growth rate, genetic stability and fermentation ability. At 1.6 g/L vanillin concentration, the average OD600 value obtained for mutant strains was 0.95 and thus about 3.4-fold higher than for the wild-type. When the concentration of vanillin was 2.0 g/L, the glucose utilization rate of the mutant was 86.3 % within 96 h, while that of the original strain was only 70.0 %. At this concentration of vanillin, the mitochondrial membrane potential of the mutant strain recovered faster than that of the original strain, and the ROS scavenging ability was stronger. We analyzed the whole transcriptome sequencing map and the whole genome resequencing of the mutant, and found that DEGs such as FLO9, GRC3, PSP2 and SWF1, which have large differential expression multiples and obvious mutation characteristics, play an important role in cell flocculation, rDNA transcription, inhibition of DNA polymerase mutation and protein palmitoylation. These functions can help cells resist vanillin stress. The results show that combining HIR with ALE is an effective mutagenesis strategy. This approach can efficiently obtain Saccharomyces cerevisiae mutants with improved vanillin tolerance, and provide reference for obtaining robust yeast strains with lignocellulose inhibitor tolerance.

Comparison of cell delivery and cell membrane camouflaged PLGA nanoparticles in the delivery of shikonin for colorectal cancer treatment.

Inspired by the "natural camouflage" strategy, cell-based biomimetic drug delivery systems (BDDS) have shown great potential in cancer therapy. Red blood cell (RBC) delivery vehicles and red blood cell membrane (RBCm)-camouflaged vehicles were commonly used strategies for drug delivery. We prepared shikonin-encapsulated PLGA nanoparticles (PLGA/SK) with different surface charges to obtain both RBC delivery and RBCm-camouflaged PLGA NPs. The physicochemical properties, in vivo circulation and antitumor effects of these biomimetic preparations were studied. Since the positive PLGA NPs may affect the morphology and function of RBCs, the biomimetic preparations prepared by the negative PLGA NPs showed better in vitro stability. However, positive PLGA NP-based biomimetic preparations exhibited longer circulation time and higher tumor region accumulation, leading to stronger anti-tumor effects. Meanwhile, the RBC delivery PLGA(+) NPs possessed better in vitro cytotoxicity, longer circulation time and higher tumor accumulation than RBCm-camouflaged PLGA(+) NPs. Collectively, RBC delivery vehicles possessed more potential than RBCm-camouflaged vehicles on drug delivery for tumor treatment, especially with positive NPs-loaded.

Fluorescent strategy based on cationic conjugated polymer fluorescence resonance energy transfer for the quantification of 5-(hydroxymethyl)cytosine in genomic DNA.

DNA methylation is dynamically reprogrammed during early embryonic development in mammals. It can be explained partially by the discovery of 5-(hydroxymethyl)cytosine (5-hmC), 5-formylcytosine (5-fC), and 5-carboxylcytosine (5-caC), which are identified as key players involved in both active and passive demethylation pathways. As one of the ten-eleven translocation oxidation products, 5-hmC was found relatively abundant in neuron cells and embryonic stem cells. Herein we report a new method for 5-hmC quantification in genomic DNA based on CCP-FRET (cationic conjugated polymers act as the energy donor and induce fluorescence resonance energy transfer) assay combined with KRuO4 oxidation. 5-hmC in genomic DNA can be selectively transformed into 5-fC by the oxidation of KRuO4 and then labeled with hydroxylamine-BODIPY (BODIPY = 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorophore through the reaction between 5-fC and hydroxylamine-BODIPY. After the fluorescently labeled DNA was captured by CCP through electrostatic interactions, a significant FRET between CCP and hydroxylamine-BODIPY fluorophore was observed. This CCP-FRET-based assay benefits from light-harvesting, large Stokes shift, and optical signal amplification properties of the CCP. Furthermore, this CCP-FRET-based assay was quite successfully demonstrated for the 5-hmC quantification in three types of cells (mESc, HeLa, HEK 293T), providing a much more convenient choice for 5-hmC quantification in genomic DNA.

Preparation of a hyper-cross-linked polymer monolithic column and its application to the sensitive determination of genomic DNA methylation.

A hyper-cross-linked polymer monolithic column, poly(methacrylatoethyl trimethyl ammonium-co-vinylbenzene chloride-co-divinylbenzene) (MATE-co-VBC-co-DVB) with phenyl and quaternary ammonium groups was successfully prepared in the current study. The prepared monolith possesses large specific surface area, narrow mesopore size distribution and high column efficiency. The poly(MATE-co-VBC-co-DVB) monolithic column was demonstrated to have strong anion exchange/reversed-phase (SAX/RP) mixed-mode retention for analytes on capillary liquid chromatography (cLC). By using this monolithic column, we developed a rapid and sensitive method for the detection of DNA methylation. Our results showed that six nucleobases (adenine, guanine, cytosine, thymine, uracil, and 5-methylcytosine (5-mC)) can be baseline separated within 15 min by electrostatic repulsion and hydrophobic interactions between nucleobases and the monolithic stationary phase. The limit of detection (LOD, signal/noise = 3) of 5-mC is 0.014 pmol and endogenous 5-mC can be distinctly detected by using only 10 ng genomic DNA, which is comparable to that obtained by mass spectrometry analysis. Furthermore, by using the method developed here, we found that DNA methylation inhibitor 5-azacytidine (5-aza-C) and 5-aza-2'-deoxycytidine (5-aza-CdR) could induce a significant decrease of genome-wide DNA methylation in human lung carcinoma cells (A549) and cervical carcinoma cells (HeLa).

Does medication-related osteonecrosis of the jaw affect survival of patients with Multiple Myeloma?: Exploring a large single center database using artificial intelligence.

In addition to randomized clinical trials, consideration of Real-World Evidence is necessary for mirroring clinical reality. However, processing such evidence for large numbers of patients often requires considerable time and effort. This is particularly true for rare tumor diseases such as multiple myeloma (MM) or for adverse effects that occur even more rarely. In such cases, artificial intelligence is able to efficiently detect patients with rare conditions. One of these rare adverse events, and the most discussed, following bone protective treatment in MM is medication-related osteonecrosis of the jaw (MRONJ). The association of bone protective treatment to MM outcome has been intensively studied. However, the impact of MRONJ resulting from such treatment on MM prognosis and outcome is poorly understood. In this retrospective study, we therefore investigated the long-term effects of MRONJ. We used natural language processing (NLP) to screen individual data of 2389 MM patients to find 50 out of 52 patients with MRONJ matching our inclusion criteria. To further improve data quality, we then performed propensity score matching. In comparison to MM patients without MRONJ, we found a significantly longer overall survival (median 126 vs. 86 months) despite slightly worse clinical features.

A sutureless aortic stent-graft based on a nitinol scaffold bonded to a compliant nanocomposite polymer is durable for 10 years in a simulated in vitro model.

PURPOSE: To physiologically test the durability of a sutureless aortic stent-graft based on nitinol bonded to polyhedral oligomeric silsesquioxane (POSS) and poly(carbonate-urea) urethane (PCU) for 10 years according to Food and Drug Administration guidelines. METHODS: Aortic stent-grafts (n = 4) were tested in 37°C distilled water using simulated in vivo hydrodynamic pulse loading. After 400 million cycles, surface topography was assessed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Dynamic compliance was measured using a pulsatile flow phantom. Mechanical and elastic properties were determined by stress-strain studies and elastic deformation tests. Dynamic scanning calorimetry (DSC) and thermomechanical analysis (TMA) were used to assess thermal resistance. Comparison was made with a zero-cycled control. RESULTS: All stent-grafts successfully completed accelerated pulsatile fatigue at 94±14-mmHg pulse pressure. SEM images confirmed uniform surface topography without any fractures. FTIR showed increased intensity of -NHCO- bonds, but there was no significant sign of biodegradation. Tensile stress of fatigue-tested polymer compared favorably with the zero-cycled control at 50% to 500% strain (p = 0.69). At a mean pressure range of 60 to 120 mmHg, overall compliance of the fatigue-tested grafts was 3.48±1.27%mmHg(-1)×10(-2) with no significant difference compared to control (3.26±0.65%mmHg(-1)×10(-2); p = 0.47). DSC and TMA showed comparable thermotropic transition. CONCLUSION: Simulated physiological in vivo hydrodynamic loading has no significant degradative effect on an innovative sutureless stent-graft made from POSS-PCU nanocomposite polymer. Sutureless technology incorporating nitinol stents proved to be robust, with no separation over an accelerated 10-year cycle, which may allow development of durable stent-grafts with better compliance.