Polysaccharide-based wrinkled surfaces induced by polyion complex skin layers upon drying

Sodium alginate/gum arabic/glycerol multicomponent edible films loaded with natamycin: Study on physicochemical, antibacterial, and sweet potatoes preservation properties

Sweet potato (Ipomonea batatas Lam) is easily damaged due to its thin skin, which is limited in shelf life and causes enormous economic losses in the food industry. A new type of safe, non-toxic, and edible antibacterial functional film was developed with sodium alginate (2.5 %), gum arabic (1 %), glycerol (2 %), and natamycin as an antimicrobial agent in this study. The physical and antibacterial properties of films, such as thickness, chromaticity, water vapor permeability, tensile strength, and elongation at break, were studied. Furthermore, the antibacterial film was applied in the preservation of sweet potatoes. The results showed that natamycin emulsion had good compatibility with sodium alginate. Besides reducing the transparency of the composite membrane, the mechanical properties, barrier properties, and thermal stability of the composite film were significantly enhanced by the addition of natamycin prepared by a pH-cycle method. When the concentration of natamycin in the membrane solution reached 40 μg/mL or more, the antibacterial film had a noticeable inhibitory effect on the growth of molds, and yeasts, significantly enhancing the bacteriostatic effect of the base film. During the sweet potatoes storage, the water content, total starch content, Vc content, and flavonoid glycoside content of sweet potato showed a downward trend. However, the treatment of antibacterial film containing natamycin could slow down the physiological and quality changes of sweet potatoes during conventional storage, and the sweet potatoes still had good processing quality after 120 days of storage.

Biomimetic and bioinspired surface topographies as a green strategy for combating biofouling: a review

Biofouling refers to the adverse attachment and colonization of fouling organisms, including macromolecules, bacteria, and sessile invertebrates, on the surfaces of materials submerged in aquatic environments. Almost all structures working in watery surroundings, from marine infrastructures to healthcare facilities, are affected by this sticky problem, resulting in massive direct and indirect economic loss and enormous cost every year in protective maintenance and remedial cleaning. Traditional approaches to preventing marine biofouling primarily rely on the application of biocide-contained paints, which certainly impose adverse effects on the ocean environment and marine ecology. Biomimicry offers an efficient shortcut to developing environmentally friendly antifouling techniques and has yielded encouraging and promising results. The antifouling strategies learned from nature can be broadly classified into two categories according to the nature of the cues applied for biofouling control. One is the chemical antifouling techniques, which are dedicated to extracting the effective antifoulant compounds from marine organisms and synthesizing chemicals mimicking natural antifoulants. In contrast, the physical biomimetic (BM) antifouling practices focus on the emulation and optimization of the physical cues such as micro and nanoscale surface topographies learned from naturally occurring surfaces for better antifouling efficacy. In this review, a synopsis of the techniques for manufacturing the BM and bioinspired (BI) antifouling surface topographies is introduced, followed by the bioassay to assess the antifouling performance of the structured surfaces. Then, the BM and BI surface topographies that were reported to possess enhanced antifouling competence are introduced, followed by a summary of theoretical modeling. The whole paper is concluded by summarizing the studies' deficiencies so far and outlooking the research directions in the future.

Biointerface topography mediates the interplay between endothelial cells and monocytes

Endothelial cell (EC) monolayers located in the inner lining of blood vessels serve as a semipermeable barrier between circulating blood and surrounding tissues. The structure and function of the EC monolayer affect the recruitment and adhesion of monocytes, which plays a pivotal role in the development of inflammation and atherosclerosis. Here we investigate the effect of material wrinkled topographies on the responses of human umbilical vein endothelial cells (HUVECs) and adhesion of monocytes to HUVECs. It is found that HUVEC responses are non-linearly mediated by surface topographies with different dimensions. Specifically, more cell elongation and better cell orientation on the wrinkled surface with a 3.5 μm amplitude and 10 μm wavelength (W10) are observed compared to other surfaces. The proliferation rate of HUVECs on the W10 surface is higher than that on other surfaces due to more 5-ethynyl-2′-deoxyuridine (EdU) detected on the W10 surface. Also, greater expression of inflammatory cytokines from HUVECs and adhesion of monocytes to HUVECs on the W10 surface is shown than other surfaces due to greater expression of p-AKT and ICAM, respectively. This study offers a new in vitro system to understand the interplay between HUVEC monolayers and monocytes mediated by aligned topographies, which may be useful for vascular repair and disease modeling for drug testing.

This study offers a new in vitro system to understand the interplay between HUVEC monolayer and monocytes mediated by aligned topographies, which may be useful for vascular repair and disease modeling for drug testing.