Polysaccharide-Based Coating with Excellent Antibiofilm and Repeatable Antifouling-Bactericidal Properties for Treating Infected Hernia.

In recent years, the utilization of medical devices has gradually increased and implantation procedures have become common treatments. However, patients are susceptible to the risk of implant infections. This study utilized chemical grafting to immobilize polyethylenimine (QPEI) and hyaluronic acid (HA) on the surface of the mesh to improve biocompatibility while being able to achieve antifouling antimicrobial effects. From the in vitro testing, PP-PDA-Q-HA exhibited a high antibacterial ratio of 93% against S. aureus, 93% against E. coli, and 85% against C. albicans. In addition, after five rounds of antimicrobial testing, the coating continued to exhibit excellent antimicrobial properties; PP-PDA-Q-HA also inhibits the formation of bacterial biofilms. In addition, PP-PDA-Q-HA has good hemocompatibility and cytocompatibility. In vivo studies in animal implantation infection models also demonstrated the excellent antimicrobial properties of PP-PDA-Q-HA. Our study provides a promising strategy for the development of antimicrobial surface medical materials with excellent biocompatibility.

Antimicrobial Peptide-Conjugated Hierarchical Antifouling Polymer Brushes for Functionalized Catheter Surfaces.

Catheter-related infection is a great challenge to modern medicine, which causes significant economic burden and increases patient morbidity. Hence, there is a great requirement for functionalized surfaces with inherently antibacterial properties and biocompatibility that prevent bacterial colonization and attachment of blood cells. Herein, we developed a strategy for constructing polymer brushes with hierarchical architecture on polyurethane (PU) via surface-initiated atom-transfer radical polymerization (SI-ATRP). Surface-functionalized PU (PU-DMH) was readily prepared, which comprised of poly(3-[dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate) (PDMAPS) brushes as the lower layer and antimicrobial peptide-conjugated poly(methacrylic acid) (PMAA) brushes as the upper layer. The PU-DMH surface showed excellent bactericidal property against both Gram-positive and Gram-negative bacteria and could prevent accumulation of bacterial debris on surfaces. Simultaneously, the PU-DMH samples possessed good hemocompatibility and low cytotoxicity. Furthermore, the integrated antifouling and bactericidal properties of PU-DMH under hydrodynamic conditions were confirmed by an in vitro circulating model. The functionalized surface possessed persistent antifouling and bactericidal performances both under static and hydrodynamic conditions. The microbiological and histological results of animal experiments also verified the in vivo anti-infection performance. The present work might find promising clinical applications for preventing catheter-related infection.

[Correction of the projection center of rotation based on the sinogram using translation matching method].

The accurate position of the center of rotation (COR) is a key factor to ensure the quality of computed tomography (CT) reconstructed images. The classic cross-correlation matching algorithm can not satisfy the requirements of high-quality CT imaging when the projection angle is 0 and 180°, and thus needs to be improved and innovated. In this study, considering the symmetric characteristic of the 0° and flipped 180° projection data in sinogram, a novel COR correction algorithm based on the translation and match of the 0° and 180° projection data was proposed. The OTSU method was applied to reduce noise on the background, and the minimum offset of COR was quantified using the L1-norm, and then a precise COR was obtained for the image correction and reconstruction. The Sheep-Logan simulation model with random gradients and Gaussian noise and the real male SD rats samples which contained the heterogenous tooth image and the homogenous liver image, were adopted to verify the performance of the new algorithm and the cross-correlation matching algorithm. The results show that the proposed algorithm has better robustness and higher accuracy of the correction (when the sampled data is from 10% to 50% of the full projection data, the COR value can still be measured accurately using the proposed algorithm) with less computational burden compared with the cross-correlation matching algorithm, and it is able to significantly improve the quality of the reconstructed images.

Influence of different education approaches on the implantation performance of dental practitioners in aesthetic zone.

PURPOSE: To investigate the influence of different education approaches on the implantation performance (operation time, three-dimensional deviation) of inexperienced operators. METHODS: Eighteen students who met the inclusion criteria were randomly assigned to traditional training group or digital training group. After training, the average operation time and implant deviation (platform deviation, apex deviation, and angle deviation) of the two groups were calculated by Student's t-test. A self-developed questionnaire was used to evaluate the students' grasp of clinical knowledge and skill. RESULT: Compared with the traditional training group, the duration of implant installation and temporary prosthesis placement of the digital training group decreased significantly (p < 0.05). The implant deviation of the digital training group was lower than that of the traditional training group. The apex deviation (p = 0.015) and angle deviation (p = 0.015) significantly improved with digital training, but differences in platform deviation (p = 0.065) were not statistically significant. The questionnaire survey showed that the overall perception of the inexperienced operators in the digital training group was better than that in the traditional training group. CONCLUSION: In the hands of inexperienced operators, digital training reduced the operation time and improved the implant accuracy in comparison with traditional training.

A digital workflow to predict facial aesthetics in patients with maxillofacial trauma with implant retained prostheses.

Purpose To introduce a digital workflow for the prediction of facial aesthetics, especially in patients with dentation deformity caused by maxillofacial trauma.Methods Cone-beam computed tomography (CBCT) and three-dimensional facial scans of patients with radiographic prostheses were collected. The aforementioned data were uploaded to ProPlan CMF software and merged to generate a virtual patient with craniofacial hard tissue, realistic facial soft tissue, and remaining dentition. The radiographic prostheses were scanned to form a digital cast, which was fitted with its CBCT image to create the virtual prostheses. Postoperative facial soft tissue was simulated according to the movement of the virtual prostheses. An appropriate virtual diagnostic prosthesis plan was selected by the patient and dentist. Subsequently, prosthetically driven implant guide and restoration were designed and fabricated.Conclusions A virtual patient was successfully constructed. A 4-mm protrusion of the virtual prosthesis was chosen. Subsequently, implant surgery was performed, and dental prostheses were fabricated based on this location. The fusion of the postoperative facial scan and preoperative facial prediction was found to be coincident. This technique can effectively predict facial aesthetic features of patients with maxillofacial trauma, facilitate communication with patients, reduce chairside time, and guide the multidisciplinary design of implant placement and restoration fabrication.

3D ring artifacts removal algorithm combined low-rank tensor decomposition with spatial-sequential total variation regularization and its application in phase-contrast microtomography.

PURPOSE: High-resolution synchrotron radiation X-ray phase contrast microtomography (PC-µCT) images often suffer from severe ring artifacts, which are mainly caused by undesirable responses of detector elements. In the medical imaging field, the existence of ring artifacts can lead to degraded visual quality and can directly affect diagnosis accuracy. Thus, removing or at least effectively reducing ring artifacts is indispensable. METHOD: The existing ring artifacts removal algorithms mainly focus on two-dimensional (matrix-based) priors, and these algorithms fail to consider correlations hidden in sequential computed tomography (CT) images. This paper proposed a novel three-dimensional (tensor-based) ring artifacts removal algorithm for synchrotron radiation X-ray PC-µCT images. In the sinogram domain, ring artifacts manifest as vertical stripe artifacts. From an image decomposition perspective, a degraded sinogram can be decomposed into a stripe artifacts component and an underlying clean sinogram component. The proposed algorithm is designed to detect and remove stripe artifacts from a degraded sinogram by fully identifying the characteristics of the two components. Specifically, for the stripe artifacts component, tensor Tucker decomposition is used to describe its low-rank character. For the underlying clean sinogram component, spatial-sequential total variation regularization is adopted to enhance the piecewise smoothness. Moreover, the Frobenius norm term is further used to model Gaussian noise. An efficient augmented Lagrange multiplier method is designed to solve the proposed optimization model. RESULTS: The proposed method is evaluated utilizing both simulations and real data containing different ring artifacts patterns. In the simulations, the human chest CT images are used for evaluating the proposed method. We compare the peak signal-to-noise ratio (PSNR), structural similarity (SSIM), and mean absolute error (MAE) results of our algorithm with the Naghia's method, the RRRTV method, the wavelet-FFT method, and the SDRSD-GIF method. The proposed method was also evaluated on real data from rat liver samples and rat tooth samples. Our proposed method outperforms the competing methods in terms of both qualitative and quantitative evaluation results. Additionally, the 3D visualization results were presented to make the ring artifacts removal effect more intuitive. CONCLUSION: The experimental results on simulations and real data clearly demonstrated that the proposed algorithm can significantly improve the quality of PC-µCT images compared with the existing popular algorithms, and it has great potential to promote the application of high-resolution imaging for visualizing biological tissues.

Well-Defined Gold Nanorod/Polymer Hybrid Coating with Inherent Antifouling and Photothermal Bactericidal Properties for Treating an Infected Hernia.

Biomedical device-associated infection (BAI) is a great challenge in modern clinical medicine. Therefore, developing efficient antibacterial materials is significantly important and meaningful for the improvement of medical treatment and people's health. In the present work, we developed a strategy of surface functionalization for multifunctional antibacterial applications. A functionalized polyurethane (PU, a widely used biomedical material for hernia repairing) surface (PU-Au-PEG) with inherent antifouling and photothermal bactericidal properties was readily prepared based on a near-infrared (NIR)-responsive organic/inorganic hybrid coating which consists of gold nanorods (Au NRs) and polyethylene glycol (PEG). The PU-Au-PEG showed a high efficiency to resist adhesion of bacteria and exhibited effective photothermal bactericidal properties under 808 nm NIR irradiation, especially against multidrug-resistant bacteria. Furthermore, the PU-Au-PEG could inhibit biofilm formation long term. The biocompatibility of PU-Au-PEG was also proved by cytotoxicity and hemolysis tests. The in vivo photothermal antibacterial properties were first verified by a subcutaneous implantation animal model. Then, the anti-infection performance in a clinical scenario was studied with an infected hernia model. The results of animal experiment studies demonstrated excellent in vivo anti-infection performances of PU-Au-PEG. The present work provides a facile and promising approach to develop multifunctional biomedical devices.

Self-adaptive antibacterial surfaces with bacterium-triggered antifouling-bactericidal switching properties.

Catheter-induced infection is a severe problem in clinical practice, which induces significant morbidity, mortality and treatment costs. Therefore, there is a great requirement for developing antibacterial surfaces of catheter materials. In the present study, we develop a strategy for constructing self-adaptive antibacterial surfaces with bacterium-triggered antifouling-bactericidal switching properties on polyurethane (PU) via surface-initiated atom-transfer radical polymerization (SI-ATRP). Polymer coating with one hierarchical structure was readily constructed on the PU surface (PU-PQ-PEG), which was composed of poly[2-(dimethyl decyl ammonium)ethyl methacrylate] (PQDMAEMA) brushes as the bactericidal lower layer and polyethylene glycol (PEG) as the antifouling upper layer. The two layers were incorporated with Schiff base structures, which could be broken by the metabolism of bacteria. Under normal and mild infection conditions, PU-PQ-PEG showed excellent antifouling and biocompatible properties against proteins and bacteria. When serious infection occurred and bacteria colonized on the PU-PQ-PEG surface, the bacteria could trigger the self-adaptive antifouling-bactericidal switching of the surface. Furthermore, the self-adaptive antibacterial properties of PU-PQ-PEG were also confirmed by an in vitro circulating model to simulate hydrodynamic conditions. PU-PQ-PEG showed self-adaptive antibacterial performances both under static and hydrodynamic conditions. The results of animal experiments also demonstrated the in vivo anti-infection performance. The present work will provide a promising strategy for developing antibacterial surfaces of catheter materials with hemocompatibility.

Dual-Functional Implants with Antibacterial and Osteointegration-Promoting Performances.

Multifunctional antibacterial materials have great significance for treating biomedical device-associated infections (BAIs). In the present work, a facile and rational strategy was developed to produce dual-functional implants with antibacterial and osteointegration-promoting properties for the treatment of BAI. A titanium implant, as a representative demo of implants, was first functionalized with ethanediamine-functionalized poly(glycidyl methacrylate) (PGED) brushes. Then, low-molecular-weight quaternized polyethyleneimine (QPEI, a cationic antibacterial agent) and alendronate (ALN, a clinically used drug with high affinity for bone minerals) were covalently conjugated onto PGED brushes to produce dual-functional dental implants (Ti-AQ). The QPEI component imparted Ti-AQ with antibacterial abilities, and the ALN component could balance the cytotoxicity of a cationic antibacterial agent, improving the biocompatibility for osteoblast cells. The effective performances of anti-infection and osteointegration were demonstrated in a BAI animal model. The results indicated that Ti-AQ inhibited bacterial infection at the early stage and enhanced the osteointegration and biomechanical properties between the implants and bone tissues at the late stage. This study will provide one facile and universal strategy for the design and development of novel multifunctional antibacterial implants.

Properties of hydrodynamic J-type countercurrent chromatography for protein separation using aqueous two-phase systems: With special reference to constructing conical columns.

Protein separation using hydrodynamic countercurrent chromatography (CCC), where low backpressure is inherent, is more challenging, more time consuming and more costly when compared with separating small molecules. The most hopeful approach is to rationally design suitable columns for already commercialized J-type CCC machinery. By comparing 3 column geometries (3D helix, 2D spiral and 3D cone), we firstly constructed the mechanical model tailored to the conical column on J-type CCC using aqueous two-phase system (ATPS) on protein separation. Aimed at mechanistically understanding hydrodynamic CCC, we then developed a semi-quantitative model to account for contributions of both hydrodynamic and hydrostatic forces to stationary phase retention, and have subsequently compared the modelling outcomes with experimental results. We practiced a methodology to delineate both phase mixing and stationary phase retention before committing to physically constructing CCC columns. Following theoretical analyses, we finally constructed conical columns for J-type CCC. Using model proteins (myoglobin and lysozyme) and with 2 ATPSs containing PEG1000 and phosphate, sound protein separation has been achieved (resolution reaches 1.5-2.0 and stationary phase retention also exceeds 40%) for the selected ATPSs and under a varied level of sample volumes and loadings.

Interfacial molecular interactions based on the conformation recognition between the insoluble antitumor drug AD-1 and DSPC.

In this study, molecular interactions between the anti-cancer agent 20(R)-25-methoxyl-dammarane-3ß, 12ß, 20-triol (AD-1) and phospholipid 1,2-Distearoyl-sn-glycero-3-phosphocholine (DSPC) were investigated using the Langmuir film balance technique. The characteristics of binary Langmuir monolayers consisting of DSPC and AD-1 were conducted on the basis of the surface pressure-area per molecule (π-A) isotherms. It was found that the drug was able to become efficiently inserted into preformed DSPC monolayers, indicating a preferential interaction between AD-1 and DSPC. For the examined lateral pressure at 20mN/m, the largest negative values of ΔGex were found for the AD-1/DSPC monolayer, which should be the most stable. Based on the calculated values of ΔGex, we found that the AD-1/DSPC systems exhibited the best mixed characteristics when the molar fraction of the AD-1 was 0.8; at that relative concentration, the AD-1 molecules can mix better and interact with the phospholipid molecules. In addition, the drug-DSPC binary supramolecular structure was also deposited on the mica plates as shown by atomic force microscopy (AFM). Finally, molecular docking calculations explained satisfactorily that, based on the conformations interactions (conformation recognition), even at an AD-1/DSPC molar ratio as high as 8:2, the interfacial stabilization of the AD-1/DSPC system was fairly strong due to hydrophobic interactions. A higher loading capacity of DSPC might be possible, as it is associated with a more flexible geometrical environment, which allows these supramolecular structures to accept larger increases in drug loading upon steric binding.

Oral nano-delivery of anticancer ginsenoside 25-OCH3-PPD, a natural inhibitor of the MDM2 oncogene: Nanoparticle preparation, characterization, in vitro and in vivo anti-prostate cancer activity, and mechanisms of action.

The Mouse Double Minute 2 (MDM2) oncogene plays a critical role in cancer development and progression through p53-dependent and p53-independent mechanisms. Both natural and synthetic MDM2 inhibitors have been shown anticancer activity against several human cancers. We have recently identified a novel ginsenoside, 25-OCH3-PPD (GS25), one of the most active anticancer ginsenosides discovered thus far, and have demonstrated its MDM2 inhibition and anticancer activity in various human cancer models, including prostate cancer. However, the oral bioavailability of GS25 is limited, which hampers its further development as an oral anticancer agent. The present study was designed to develop a novel nanoparticle formulation for oral delivery of GS25. After GS25 was successfully encapsulated into PEG-PLGA nanoparticles (GS25NP) and its physicochemical properties were characterized, the efficiency of MDM2 targeting, anticancer efficacy, pharmacokinetics, and safety were evaluated in in vitro and in vivo models of human prostate cancer. Our results indicated that, compared with the unencapsulated GS25, GS25NP demonstrated better MDM2 inhibition, improved oral bioavailability and enhanced in vitro and in vivo activities. In conclusion, the validated nano-formulation for GS25 oral delivery improves its molecular targeting, oral bioavailability and anticancer efficacy, providing a basis for further development of GS25 as a novel agent for cancer therapy and prevention.

Preparative separation and purification of rosmarinic acid from perilla seed meal via combined column chromatography.

In this study, the preparative separation and purification of rosmarinic acid (RA) from perilla seed meal (PSM), which is a by-product of edible oil production, was achieved using combined column chromatography over macroporous and polyamide resins. To optimize the RA enrichment process, the performance and separation characteristics of nine selected macroporous resins with different chemical and physical properties were investigated. SP825 resin was the most effective: the content of RA increased from 0.27% in the original extract to 16.58% in the 50% ethanol fraction (a 61.4-fold increase). During further purification treatment on polyamide resin, 90.23% pure RA could be obtained in the 70% ethanol fraction. RA with a higher purity (>95%) could also be easily obtained using one crystallization operation. The proposed method is simple, easily operated, cost-effective, and environmentally friendly and is suitable for both large-scale RA production and waste management.

In vitro dissolution and in vivo gamma scintigraphic evaluation of press-coated salbutamol sulfate tablets.

The aim of this study was to investigate the in vitro and in vivo performance of salbutamol sulfate press-coated tablets for delayed release. The in vitro release behavior of press-coated tablets with the outer layer of PEG 6000/ Eudragit S100 blends (2:1) in pH 1.2 (0.1 mol L-1 HCl) and then pH 6.8 buffer solution was examined. Morphological change of the press-coated tablet during in vitro release was recorded with a digital camera. Release of salbutamol sulfate from press-coated tablets was less than 5 % before 3 h and was completed after 8 h in pH 6.8 phosphate buffer solution. In vivo gamma scintigraphy study carried out on healthy men indicated that the designed system released the drug in lower parts of the GI tract after a lag time of 5 hours. The results showed the capability of the system of achieving delayed release of the drug in both in vitro and in vivo gamma scintigraphy studies.