In Situ Growth of Functional Hydrogel Coatings by a Reactive Polyurethane for Biomedical Devices.

Surface modification of thermoplastic polyurethane (TPU) could significantly enhance its suitability for biomedical devices and public health products. Nevertheless, customized modification of polyurethane surfaces with robust interfacial bonding and diverse functions via a simple method remains an enormous challenge. Herein, a novel thermoplastic polyurethane with a photoinitiated benzophenone unit (BPTPU) is designed and synthesized, which can directly grow functional hydrogel coating on polyurethane (PU) in situ by initiating polymerization of diverse monomers under ultraviolet irradiation, without the involvement of organic solvent. The resulting coating not only exhibits tissue-like softness, controllable thickness, lubrication, and robust adhesion strength but also provides customized functions (i.e., antifouling, stimuli-responsive, antibacterial, and fluorescence emission) to the original passive polymer substrates. Importantly, BPTPU can be blended with commercial TPU to produce the BPTPU-based tube by an extruder. Only a trace amount of BPTPU can endow the tube with good photoinitiated capacity. As a proof of concept, the hydrophilic hydrogel-coated BPTPU is shown to mitigate foreign body response in vivo and prevent thrombus formation in rat blood circulation without anticoagulants in vitro. This work offers a new strategy to guide the design of functional polyurethane, an elastomer-hydrogel composite, and holds great prospects for clinical translation.

Zwitterionic nanocapsule-based wound dressing with the function of gradient release of multi-drugs for efficient wound healing.

Efficient wound healing has attracted great interest due to the prevalence of skin damage. It is still highly desired yet challenging to construct a multi-drug loaded wound dressing that can release different drugs at different times to meet specific requirements towards different healing stages. Herein, a wound dressing was developed based on thermoresponsive zwitterionic nanocapsules (ZNs) that were sandwiched between two double-layered fabrics to regulate the multiple drug release pathway. The salt-response of the obtained ZNs was greatly suppressed while its transition temperature was regulated to be ∼37 °C to fit the needs of the physiological environment. Two bioactive substances, human basic fibroblast growth factor (bFGF) for tissue regeneration and norfloxacin for anti-inflammation, were loaded in the ZNs and on the surface of fabrics, respectively, to achieve separative gradient release. The in vitro drug release tests revealed that norfloxacin could be released relatively fast (∼24 h) while the release rate of bFGF was much slower (∼168 h), matching the specific time requirements of inflammation and proliferation stages very well. The in vivo wound healing experiment also confirmed the high wound healing efficiency of the wound dressing developed here, compared to the wound dressings without gradient release characteristics. We believe the strategy illustrated here will provide new insights into the design and biomedical applications of zwitterionic nanocapsules.

Design of novel temperature-resistant and salt-tolerant acrylamide-based copolymers by aqueous dispersion polymerization.

Development of polymer-based flooding technology to improve oil recovery efficiency, water dispersion copolymerization of acrylamide, cationic monomer methacryloxyethyltrimethyl ammonium chloride (METAC), and anionic monomer acrylic acid (AA) were carried out in aqueous ammonium sulfate solution with polyvinyl pyrrolidone (PVP) as the stabilizer. The copolymers were characterized by 1H-NMR, FT-IR, TG, and SEM to confirm that they were prepared successfully and exhibited excellent salt-resistant property. Moreover, the effect of the aqueous solution of ammonium sulfate (AS) concentration, stabilizer concentration, and initiator concentration on the viscosity and size were systematically investigated. To further improve the thermal endurance properties of copolymer, hydrophobic monomers with different alkyl chain lengths were added to the above system. The acrylamide-based quadripolymer possessed prominent thermal and salt endurance properties by utilizing the advantages of zwitterionic structure and hydrophobic monomer. With the temperature rising, the viscosity retention could reach 70.2% in the water and 63.8% in the saline. This work had expected to provide a new strategy to design polymers with excellent salinity tolerance and thermal-resistance performances.

Zwitterionic Nanocapsules with Salt- and Thermo-Responsiveness for Controlled Encapsulation and Release.

Intelligent polymer nanocapsules that can not only encapsulate substances efficiently but also release them in a controllable manner hold great potential in many applications. To date, although intensive efforts have been made to develop intelligent polymer nanocapsules, how to construct the well-defined core/shell structure with high stability via a straightforward method remains a considerable challenge. In this work, the target novel zwitterionic nanocapsules (ZNCs) with a stable hollow structure were synthesized by inverse reversible addition fragmentation transfer (RAFT) miniemulsion interfacial polymerization. The shell gradually grew from the water/oil interface due to the interfacial polymerization, accompanied by the cross-linking of the polyzwitterionic networks, where the core/shell structure could be well-tuned by adjusting the precursor compositions. The resultant ZNCs exhibited a salt-/thermo-induced swelling behavior through the phase transition of the external zwitterionic polymers. To further investigate the functions of ZNCs, different substances, such as methyl orange and bovine serum albumin (BSA), were encapsulated into the ZNCs with a high encapsulation efficiency of 89.3 and 93.6%, respectively. Interestingly, the loaded substances can be controllably released in aqueous solution triggered by salt or temperature variations, and such responsiveness also can be utilized to bounce off the bacteria adhered on target surfaces. We believe that these designed salt- and thermo-responsive intelligent polymer nanocapsules with well-defined core/shell structures and antifouling surfaces should be a promising platform for biomedical and saline related applications.

Mussel-Inspired Polymeric Coatings to Realize Functions from Single and Dual to Multiple Antimicrobial Mechanisms.

Numerous efforts to fabricate antimicrobial surfaces by simple yet universal protocols with high efficiency have attracted considerable interest but proved to be particularly challenging. Herein, we designed and fabricated a series of antimicrobial polymeric coatings with different functions from single to multiple mechanisms by selectively utilizing diethylene glycol diglycidyl ether (PEGDGE), polylysine, and poly[glycidylmethacrylate-co-3-(dimethyl(4-vinylbenzyl)ammonium)propyl sulfonate] (poly(GMA-co-DVBAPS)) via straightforward mussel-inspired codeposition techniques. Bactericidal polylysine endowed the modified surfaces with a high ability (∼90%) to kill attached bacteria, while PEGDGE components with unique surface hydration prevented bacterial adhesion, avoiding the initial biofilm formation. Moreover, excellent salt-responsive poly(GMA-co-DVBAPS) enabled reactant polymeric coatings to change chain conformations from shrinkable to stretchable state and subsequently release >90% attached bacteria when treated with NaCl solution, even after repeated cycles. Therefore, the obtained polymeric coatings, polydopamine/poly(GMA-co-DVBAPS) (PDA/PDV), polydopamine/polylysine/poly(GMA-co-DVBAPS) (PDA/l-PDV), and polydopamine/polylysine/poly(GMA-co-DVBAPS)/diethylene glycol diglycidyl ether (PDA/l-PDV-PEGDGE), controllably realized functions from single and dual to multiple antimicrobial mechanisms, as evidenced by long-term antifouling activity to bacteria, high bactericidal efficiency, and salt-responsive bacterial regeneration performance with several bacterial killing-release cycles. This study not only contributes to mussel-inspired chemistry for polymeric coatings with controllable functions but also provides a series of reliable and highly efficient antimicrobial surfaces for potential biomedical applications.

Novel Salt-Responsive SiO2@Cellulose Membranes Promote Continuous Gradient and Adjustable Transport Efficiency.

Continuously growing interest in the controlled and tunable transport or separation of target molecules has attracted more attention recently. However, traditional "on-off" stimuli-responsive membranes are limited to nongradient feedback, which manifests as filtration efficiency that cannot be increased or decreased gradually along with the different stimuli conditions; indeed, only the transformation of on/off state is visible. Herein, we design and fabricate a series of robust salt-responsive SiO2@cellulose membranes (SRMs) by simply combining salt-responsive poly[3-(dimethyl(4-vinylbenzyl)ammonium)propyl sulfonate] (polyDVBAPS)-modified SiO2 nanoparticles and cellulose membranes under negative-pressure filtering. The antipolyelectrolyte effect induces stretch/shrinkage of polyDVBAPS chains inside the channels and facilities the directional aperture size and surface wettability variation, greatly enhancing the variability of interfacial transport and separation efficiency. Due to the linear salt-responsive feedback mechanism, the optimal SRMs achieve highly efficient target macromolecule separation (>75%) and rapid oil/saline separation (>97%) with a continuous gradient and adjustable permeability, instead of simply an "on-off" switch. The salt-responsive factors (SiO2-polyDVBAPS) could be reversibly separated or self-assembled to membrane substrates; thus, SRMs achieved unprecedented repeatability and reusability even after long-term cyclic testing, which exceeds those of currently reported membranes. Such SRMs possess simultaneously a superfast responsive time, a controllable gradient permeability, a high gating ratio, and an excellent reusability, making our strategy a potentially exciting approach for efficient osmotic transportation and target molecule separation in a more controllable manner.

The impact of ultrasound-guided high-intensity focused ultrasound for uterine fibroids on ovarian reserve.

Objective: To evaluate the impact of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for uterine fibroids on ovarian reserve in women of reproductive age.Materials and methods: From September 2015 to September 2017, 84 patients with uterine fibroids in reproductive age were enrolled from Chongqing Haifu Hospital, Three Gorges Central Hospital of Chongqing and Aegisroen obstetric gynecology Clinic of Seoul, Korea. Blood was collected before HIFU treatment and 6 months after USgHIFU treatment. The enzyme-linked immune analysis was used for assay of circulating anti-Mullerian hormone (AMH).Results: All the 84 patients were successfully treated with USgHIFU and 67 patients completed the follow-up. The median age of the 67 patients was 38 years at the time of treatment. The median AMH value before and 6 months after treatment was 1.26 ng/mL and 1.27 ng/mL, respectively. Patients who completed AMH measurements 6 months after treatment were further classified into three groups based on age, including younger than 35 years, 36 to 40 years, and older than 40 years. The median AMH values before treatment were 3.04 ng/mL, 1.73 ng/mL and 0.87 ng/mL, and the corresponding values 6 months after treatment were 3.24, 1.44 and 0.75, respectively. A significant difference in AMH level was observed in the group of patients at the age between 36 and 40 years (p < 0.05), but no significant difference in AMH levels was observed in the other two groups (p > 0.05).Conclusion: Based on our results, we conclude that USgHIFU has no influence on ovarian reserve.

Electric Assisted Salt-Responsive Bacterial Killing and Release of Polyzwitterionic Brushes in Low-Concentration Salt Solution.

Polyzwitterionic brushes with strong antipolyelectrolyte effects have shown great potential as versatile platforms for the development of switchable friction/lubrication and bacterial absorption/desorption surfaces. However, the surface property switches of these brushes are usually triggered by high salt concentrations (>0.53 M), thereby greatly limiting their applications in biological fields where the salt concentration for mammals is ?0.15 M. To solve this problem, an electric field was used to assist the salt-responsive process of the polyzwitterionic brushes to achieve bacterial release at low concentrations of the salt solution. Briefly, poly(3-(dimethyl (4-vinylbenzyl) ammonium) propyl sulfonate) (polyDVBAPS) brushes grafted on ITO surfaces were prepared by surface initiated atom transfer radical polymerization. The bacterial release of this surface was conducted under an electric field, where anions were migrated and enriched around the brush-grafted ITO surface as anode. The local high concentration ion led to the conformation change of the brush and release of the attached bacteria. The effect of salt type, salt concentration, electric field strength, and conducting time on the bacterial release properties were investigated. The results indicated that under an electrical field of 3 V/mm, polyDVBAPS showed release capacities of ?93% for E. coli and ?81% for S. aureus in 0.12 M NaCl electrolyte solution. Furthermore, by the introduction of a bactericidal agent, i.e., Triclosan (TCS), an antibacterial surface with dual functions of killing and release was fabricated. This surface could kill ?90% and release 95% of attached E. coli in a 0.12 M NaCl solution by the application of a 3 V/mm electric field. This work demonstrated the feasibility of triggering a salt-responsive behavior of polyzwitterionic at low salt concentration by assistance of electric field, which would greatly extend the applications of polyzwitterionic, in particular in biological applications.

High-intensity focused ultrasound (HIFU) for adenomyosis: Two-year follow-up results.

OBJECTIVE: To evaluate the long-term improvement of clinical symptoms of adenomyosis after treatment with ultrasound-guided high intensity focused ultrasound (USgHIFU). METHODS: From January 2010 to December 2011, 350 patients with adenomyosis were treated with USgHIFU. Among the 350 patients, 224 of them completed the two years follow-up. The patients were followed up at 3 months, 1 year, and 2 years after HIFU treatment. Adverse effects and complications were recorded. RESULTS: All patients completed HIFU ablation without severe postoperative complications. 203 of the 224 patients who showed varying degrees of dysmenorrhea before treatment had the symptom scores decreased significantly after treatment (P<0.001). The relief rate was 84.7%, 84.7%, and 82.3%, respectively at 3 months, 1 year, and 2 years after treatment. The menstrual volume in 109 patients with menorrhagia was significantly improved after treatment (P<0.001) with a relief rate of 79.8%, 80.7%, and 78.9%, respectively at 3 months, 1 year, and 2 years after HIFU treatment. CONCLUSION: With its ability to sustain long-term clinical improvements, HIFU is a safe and effective treatment for adenomyosis.

Effects of oxytocin on high intensity focused ultrasound (HIFU) ablation of adenomysis: a prospective study.

OBJECTIVE: To investigate the effects of oxytocin on high-intensity focused ultrasound (HIFU) ablation for the treatment of adenomyosis. MATERIALS AND METHODS: Eighty-six patients with adenomyosis from three hospitals were randomly assigned to the oxytocin group or control group for HIFU treatment. During HIFU treatment, 80 units of oxytocin was added in 500ml of 0.9% normal saline running at the rate of 2ml/min (0.32U/min) in the oxytocin group, while 0.9% normal saline was used in the control group. Both patients and HIFU operators were blinded to oxytocin or saline application. Treatment results, adverse effects were compared. RESULTS: When using oxytocin, the non-perfused volume (NPV) ratio was 80.7±11.6%, the energy-efficiency factor (EEF) was 8.1±9.9J/mm(3), and the sonication time required to ablate 1cm(3) was 30.0±36.0s/cm(3). When not using oxytocin, the non-perfused volume ratio was 70.8±16.7%, the EEF was 15.8±19.6J/mm(3), and the sonication time required to ablate 1cm(3) was 58.2±72.7S/cm(3). Significant difference in the NPV ratio, EEF, and the sonication time required to ablate 1cm(3) between the two groups was observed. No oxytocin related adverse effects occurred. CONCLUSION: Oxytocin could significantly decrease the energy for ablating adenomyosis with HIFU, safely enhance the treatment efficiency.