Biodegradable Anti-Biofilm Fiber-Membrane Ureteral Stent Constructed with a Robust Biomimetic Superhydrophilic Polycationic Hydration Surface Exhibiting Synergetic Antibacterial and Antiprotein Properties.

The biofouling of ureteral stents and subsequent urinary tract infections mainly come from the adsorption and adhesion of proteins and microorganisms and their ensuing proliferation. Although general polycationic surfaces in implants have good antibacterial activities, they suffer from limited durability due to severe protein and bacterial adsorption. Here, a biodegradable and anti-biofilm fiber-membrane structured ureteral stent (FMBUS) with synergetic contact-killing antibacterial activity and antiprotein adsorption is described. The stent is prepared by generating hyperbranched poly(amide-amine)-grafted polydopamine microparticles (≈300 nm) on the surface of fibers by in situ polymerization and Schiff base reactions. The biomimetic surface endows the FMBUS with a positive charge (+21.36 mV) and superhydrophilicity (water contact angle: 0°). As a result, the stents fulfilled the following functions: i) reduced attachment of host protein due to superhydrophilicity (Lysozyme: 92.1%; human serum albumin: 39.4%); ii) high bactericidal activities against contact pathogenic bacteria (contact-killing rate: 99.9999% for both E. coli and S. aureus; antiadhesion rate: 99.2% for E. coli and 99.9999% for S. aureus); iii) biocompatibility in vitro (relative growth rate of L929: >90% on day 3) and in vivo; and iv) gradient biodegradability to avoid a second surgery of stent extraction 1-2 weeks after implantation.

[Research Progress on Artifcial Conduits for Urological Application with Antibacterial Function].

Artificial conduits, including ureteral stents and catheters, are used widely as drainage tools in the urinary system. However, various bacteria in the urine and long duration of insertion can arouse the biofilm formation on the pipeline surface, which calls for effective antibacterial strategy. In this article, the mechanism of Catheter Associated Urinary Tract Infections (CAUTI) is explained from the perspective of etiology. Then, the biofilm formation conditions and the features of urine are analyzed, the antibacterial agents and approaches suitable for ureteral stents and catheters are introduced and their pros and cons are discussed respectively.

Ultrathin, elastic, and self-adhesive nanofiber bio-tape: An intraoperative drug-loading module for ureteral stents with localized and controlled drug delivery properties for customized therapy.

During the postoperative management of urinary diseases, oral or intravenous administration of drugs and implanting ureteral stents are usually required, making localized drug delivery by ureteral stent a precise and effective medication strategy. In the traditional drug loading method, the drug was premixed in the implants in production lines and the versatility of drugs was restricted. However, the complex situation in the urinary system fails the possibility of finding a "one fits all" medication plan, and the intraoperative drug-loading of implants is highly desired to support customized therapy. Here, we designed an ultrathin (8 µm), elastic, and self-adhesive nanofiber bio-tape (NFBT) that can easily encapsulate drugs on the stent surface for controllable localized drug delivery. The NFBT exhibited high binding strength to a ureteral stent, a sustained release over 7 d in PBS for hydrophilic drug, and a zero-order release curve over 28 days for the hydrophobic drug nitrofurantoin (NFT). Further in vivo experiments using a porcine ureteral tract infection model demonstrated that NFBT loaded with NFT could significantly reduce the bacterial concentration in urine. The total amount of NFT delivered by the NFBT was about 2.68 wt% of the recommended dose for the systemic administration.

Extracellular-matrix-mimicked 3D nanofiber and hydrogel interpenetrated wound dressing with a dynamic autoimmune-derived healing regulation ability based on wound exudate.

Dynamic regulation of wound physiological signals is the basis of wound healing. Conventional biomaterials delivering growth factors to drive wound healing leads to the passive repair of soft tissues because of the mismatch of wound healing stages. Meanwhile, the bioactivity of wound exudate is often restricted by oxidation and bacterial contamination. Herein, an extracellular matrix mimicked nanofiber/hydrogel interpenetrated network (NFHIN) was constructed with a 3D nanofibrous framework for cell immigration, and interfiled aerogel containing cross-linked hyaluronic acid and hyperbranched polyamidoamine to balance the wound microenvironment. The aerogel can collect wound exudate and transform into a polycationic hydrogel with contact-killing effects even against intracellular pathogens (bactericidal rate > 99.9% in 30 min) and real-time scavenging property of reactive oxygen species. After co-culturing with the NFHIN, the bioactivity of fibroblast in theex vivoblister fluid was improved by 389.69%. The NFHIN showed sustainable exudate management with moisture-vapor transferring rate (6000 g m-2×24 h), equilibrium liquid content (75.3%), Young's modulus (115.1 ± 7 kPa), and anti-tearing behavior similar to human skin. The NFHIN can collect and activate wound exudate, turning it from a clinical problem to an autoimmune-derived wound regulation system, showing potential for wound care in critical skin diseases.

Ultra-compact MXene fibers by continuous and controllable synergy of interfacial interactions and thermal drawing-induced stresses.

Recent advances in MXene (Ti3C2Tx) fibers, prepared from electrically conductive and mechanically strong MXene nanosheets, address the increasing demand of emerging yet promising electrode materials for the development of textile-based devices and beyond. However, to reveal the full potential of MXene fibers, reaching a balance between electrical conductivity and mechanical property is still the fundamental challenge, mainly due to the difficulties to further compact the loose MXene nanosheets. In this work, we demonstrate a continuous and controllable route to fabricate ultra-compact MXene fibers with an in-situ generated protective layer via the synergy of interfacial interactions and thermal drawing-induced stresses. The resulting ultra-compact MXene fibers with high orientation and low porosity exhibit not only excellent tensile strength and ultra-high toughness, but also high electrical conductivity. Then, we construct meter-scale MXene textiles using these ultra-compact fibers to achieve high-performance electromagnetic interference shielding and personal thermal management, accompanied by the high mechanical durability and stability even after multiple washing cycles. The demonstrated generic strategy can be applied to a broad range of nanostructured materials to construct functional fibers for large-scale applications in both space and daily lives.

A novel spherical-headed fascial dilator is feasible for second-stage ultrasound guided percutaneous nephrolithotomy: A pilot study.

OBJECTIVE: In second-stage percutaneous nephrolithotomy (PCNL), because the hydronephrosis has been decompressed, the dilated renal pelvis has resolved and the space is small. Consequently, introduction of the tip of the Amplatz dilator can cause injury to the opposite side of the renal-pelvic mucosa. In this study, we report the experimental and initial clinical performance of a spherical-headed fascial dilator developed specifically for second-stage PCNL. METHODS: The novel spherical-headed dilator was compared with existing tapered-headed dilators in configuration and in puncture resistance utilizing a static puncture test. Subsequently, a pilot clinical study was conducted during which patients scheduled to undergo second-stage PCNL from June 2019 to October 2019 in our center were enrolled. A typical ultrasound guided PCNL procedure was performed with the exception that the new spherical-headed fascial dilator was substituted for a tapered-headed one. RESULTS: Experimentally, stab resistance against polyethylene film was significantly increased using the novel spherical-headed dilator compared to the traditional tapered-headed dilators (p<0.005). In the clinical study, the novel dilators were successfully introduced into the renal pelvis and passed down the collecting system in all eight second-stage PCNL cases. There were no cases of renal pelvic perforation or brisk hemorrhage nor need for transfusion. CONCLUSION: The design of the novel spherical-headed fascial dilator avoided the concentration of pressure at the tapered tip of the current Amplatz dilator by increasing the contact area and uniformly distributing and diffusing the pressure. Therefore, it is feasible to use the spherical-headed fascial dilator for second-stage PCNL.

General Strategy to Prepare Single-Layered Ag-Au-Pt Nanocrystal Ternary-Coated Biomass Textiles through Polymer-Driven Self-Assembly.

Current metal nanomaterials for developing nanofunctional textiles are mostly based on metal nanoparticles (NPs) that show aqueous instability, a tendency to aggregate, and low chemical affinity to biomass textiles, leading to low nano-metal uptake during finishing, significant declines in function, and nano-pollution. Herein, we demonstrate a strategy to transform metal (Ag, Au, and Pt) NPs into homogenous hyperbranched poly(amide-amine) (HBPAA)-encapsulated NPs showing high water solubility, oxidative resistance, and affinity to biomass materials upon surface capping with HBPAA. The proposed method represents a universal, simple, clean, and efficient self-assembly technology to produce monolayered Ag-Au-Pt ternary-coated biomass textiles. The combination of Ag, Au, and Pt NPs yields a positive potential of approximately +37.12 mV depending on the metal concentration and could simultaneously self-assemble onto natural fibers, including cotton, silk, and wool, through the one-step impregnation of textiles. Increasing the temperature and concentration of the mixture favors the self-assembly process. A mixture of 30-110 mg/L Ag, Au, and Pt NPs could nearly completely anchor onto cotton, silk, and wool textiles after impregnation at 100 °C for 1 h without chemical assistance, thereby indicating the possibility of clean production. As-prepared functional cotton, silk, and wool possessed similarly high antibacterial activities, and a mixture containing over 1500 mg/g NPs inhibited 99% of the Escherichia coli and Staphylococcus aureus in the sample textiles. The developed coating technology is simple, clean, controllable, and broadly applicable; thus, it could be potentially applied in functional textiles.

Biomimetic biodegradable Ag@Au nanoparticle-embedded ureteral stent with a constantly renewable contact-killing antimicrobial surface and antibiofilm and extraction-free properties.

Urinary tract infections (UTIs) caused by the contamination of the ureteral stent and the pain associated with secondary stent extractions are worldwide problems in the treatment of urinary tract disorders. Here, we reported a biodegradable, long-term antibacterial, and extraction-free ureteral stent with a constantly renewable contact-killing surface and an antibiofilm function achieved by constructing a hyperbranched poly(amide-amine)-capped Ag shell and Au core nanoparticle (Ag@Au NP)-embedded fiber membrane-structured poly(glycolic acid)/poly(lactic-co-glycolic acid) (PGA/PGLA) ureteral stent. The ureteral stent showed fast contact-killing properties, i.e., 5 min for Escherichia coli and 10 min for Staphylococcus aureus, with an inhibition rate higher than 99%. In addition, gradient degradation of PGA/PGLA endowed the stent with a self-cleaning property and long-term antibacterial function by continuous exfoliation of the stent surface, thereby exposing the inner Ag@Au NPs and eliminating adherent bacteria and proteins. Subsequently, in the 16-day in vitro degradation test, the stent showed durable bactericidal activity, less total release of Ag and Au elements (6.7%, ~8 µg), and low cytotoxicity (with a relative growth rate of >80% of L929 cells). In vivo experiments on a farm pig model showed that the stent exhibited a remarkable antibiofilm property and reduced the level of inflammatory and necrotic cells. After seven days of implantation, the stent showed a gradient degradation behavior and maintained structural integrity without the presence of any large fragments in the urinary system according to the B-ultrasonic examination. The as-developed biodegradable and renewable contact-killing antibacterial strategy was efficient in preparing the ureteral stent with antibiofilm and extraction-free properties to treat stent-induced UTI. Statement of significance This study presents a customized antibiofilm solution for biodegradable implants. Two particularly important aspects of this work are as follows.

An Efficient Surface Modification Strategy Improving Endothelialization with Polydopamine Nanoparticles and REDV Peptides for Stent-Grafts.

Stents or stent-grafts are often functionalized with films to enhance cell/surface interactions and improve endothelialization. However, continuous film coatings by common surface modification tactics may preclude cells from migrating along the thickness direction and may change the physical characteristics of stent-grafts. Here, polydopamine nanoparticles (PDA-NPs) are attached on braided stent-grafts tightly, forming a nanostructure on microfilaments. They also serve as the anchor for bioactive REDV peptide immobilization to promote endothelia cells (ECs) activities. The results show that braided stent-grafts decorated with PDA-NPs and REDV demonstrate an excellent endothelialization performance and hemocompatibility due to the micro/nanostructure formed and REDV affinity to ECs. The physical properties of stent-grafts are also not compromised. A potential surface modification strategy for scaffold applications is illustrated.

Experimental and analytical evaluation on the mass transfer performance of braided stent-grafts.

Endoleak and luminal loss related to blood permeation and microthrombus migration remain the main challenges in the aneurysm treatment, although stent-grafts have been widely applied. Stent-grafts provide a boundary to shield blood and microemboli transport, which are correlated with their mass transfer performance. Water permeability of vascular prostheses with woven and knitted structures has been analyzed and documented by many researchers, as well as oxygen and protein transfer. However, it is almost a total lack of blood and microemboli transfer along the braided stent-graft thickness direction. In this research, we provided a methodology for the vascular prostheses mass transfer evaluation. Braided stent-grafts in our former research were conducted on a self-developed testing system to investigate their blood permeability and microthrombus transfer behaviors. The pressure along wall thickness direction can be changed. Analytical models were also established based on pore parameters, making them applicative to different structures. Results revealed that the mass transfer behavior of stent-grafts was positively affected by porosity and pore diameter while negatively influenced by their thickness.