Poly(aspartic acid)-based self-healing hydrogel with precise antibacterial ability for rapid infected-wound repairing.

The development of wound dressings with antibacterial activities and simultaneous pro-healing functions are always urgent in treating bacterial wound infection. Herein, a novel multifunctional self-healing hydrogel was designed and prepared by crosslinking quaternary ammonium/boronic acid modified poly(aspartic acid) and poly (vinyl alcohol) polymers with targeted peptide MP196- conjugated polydopamine. The formation of this hydrogel not only improves the biocompatibility of quaternary poly(aspartic acid), but also enhances antibacterial efficacy by pH-triggering dissociation under the low pH bacterial microenvironment. Moreover, precise photothermal treatment can be achieved. In vitro study suggested high synergistic antibacterial efficiency(∼100 %) under near-infrared light, significantly higher than a single antibacterial strategy (66.0-82.6 %). In vivo study suggested infected wounds treated with the hydrogel showed an optimal healing rate(92.0 %) after 7 days. The survival rate of the bacteria in the epidermal tissues was reduced to 2.3 %. Besides, the suitable self-healing property of this hydrogel facilitated its application in the diversity of wound shapes. Thus, the novel poly(aspartic acid) hydrogel might be a promising candidate for precise therapy of bacteria-infected wounds.

A core/shell nanogenerator achieving pH-responsive nitric oxide release for treatment of infected diabetic wounds.

Nitric oxide is critical for eliminating infection and promoting regeneration in diabetic wounds. However, clinical uses of nitric oxide are limited by its high activity and lack of specificity in targeting infections. Herein, we develop an intelligent nitric oxide nanogenerator comprising isosorbide dinitrate (ISDN)-coated copper sulfide (CuS)/calcium carbonate (CaCO3) core/shell nanoparticles (CuS@CaCO3-ISDN) to target the acidic microenvironment of the infected diabetic wounds. Meaningfully, triggered by acid decomposition of CaCO3, this nanogenerator can achieve a responsive and accelerated release of nitric oxide from ISDN through enzyme-mimicking redox processes that involve CuS nanoparticles and then inactivate biofilm bacteria through the pathways of oxidative stress and disruption of adenosine triphosphate (ATP)-related energy metabolism. Moreover, after eliminating the infection, the pH-responsive release of nitric oxide can promote the proliferation of blood vessels and tissue regeneration and accelerate diabetic wound closure. This study expands the use of nitric oxide donors in wound treatment by developing the enzyme-mimicking release strategy, and the pH-responsive core/shell nanogenerator is promising for a variety of anti-infection therapeutic applications.

Multi-Stimulus Responsive Multilayer Coating for Treatment of Device-Associated Infections.

Antibacterial coating with antibiotics is highly effective in avoiding device-associated infections (DAIs) which is an unsolved healthcare problem that causes significant morbidity and mortality rates. However, bacterial drug resistance caused by uncontrolled release of antibiotics seriously restricts clinical efficacy of antibacterial coating. Hence, a local and controlled-release system which can release antibiotics in response to bacterial infected signals is necessary in antibacterial coating. Herein, a multi-stimulus responsive multilayer antibacterial coating was prepared through layer-by-layer (LbL) self-assembly of montmorillonite (MMT), chlorhexidine acetate (CHA) and Poly(protocatechuic acid-polyethylene glycol 1000-bis(phenylboronic acid carbamoyl) cystamine) (PPPB). The coating can be covered on various substrates such as cellulose acetate membrane, polyacrylonitrile membrane, polyvinyl chloride membrane, and polyurethane membrane, proving it is a versatile coating. Under the stimulation of acids, glucose or dithiothreitol, this coating was able to achieve controlled release of CHA and kill more than 99% of Staphylococcus aureus and Escherichia coli (4 × 108 CFU/mL) within 4 h. In the mouse infection model, CHA releasing of the coating was triggered by infected microenvironment to completely kill bacteria, achieving wounds healing within 14 days.

Comparative Studies of Two Major Sets of Tibetan Medical Paintings: A Historical Perspective.

Tibetan medicine, one of the time-honored medical systems in the world, has increasingly been receiving attention the world over. Tibetan medical paintings (TMP, tib. Sman thang) has become one of the focal points in the studies of this medical system. To date, there are many atlases and publications on TMP, which are principally based on the two major sets of TMP series existing today in the world, the Lhasa set and the Buryat set. It has been found that the Buryat set is based on the Lhasa set, which was brought in late 19th to the first half of the 20th century from Tibet to Buryatia, Russia. A careful investigation on the basic structure of the two sets reveals that there are many differences between the two sets of paintings, including the total number of the paintings involved, of which some are missing in one set, the details of the captions of some of the paintings, the existence of the 80th painting and its supervisor, and the overall order of the entire set, etc. The details of the differences are elaborated and discussed, and the prospective of developing the research to arrive at a standard and perfect TMP set in the future is also analyzed and anticipated.