Non-Smooth Morphologies of Typical Plant Leaf Surfaces and Their Anti-Adhesion Effects

The micromorphologies of surfaces of several typical plant leaves were investigated by scanning electron microscopy（SEM）. Different non-smooth surface characteristics were described and classified. The hydrophobicity and anti-adhesion of non-smooth leaf surfaces were quantitatively measured. Results show that the morphology of epidermal cells and the morphology and distribution density of epicuticular wax directly affect the hydrophobicity and anti-adhesion. The surface with uniformly distributed convex units shows the best anti-adhesion, and the surface with regularly arranged trellis units displays better anti-adhesion. In contrast, the surface with randomly distributed hair units performs relatively bad anti-adheslon. The hydrophobic models of papilla-ciliary and fold-setal non-smooth surfaces were set up to determine the impacts of geometric parameters on the hydrophobicity. This study may provide an insight into surface machine molding and apparent morphology design for biomimetics engineering.

Research progress of anti-adhesion after tubal obstructive infertility recanalization

Tubal obstructive infertility is one of the most common causes of female infertility.At present,the main treatment is surgical mechanical dredging and restoration of tubal anatomy.Although the success rate of recanalization is high,the postoperative reocclusion rate is also high.In addition to the destruction of fallopian tubal function,it seriously affects the long-term pregnancy rate of women.Therefore,how to reduce the re-adhesion rate after recanalization is a more concerned issue at present.This article reviews the research progress of drug therapy for anti-adhesion after recanalization of tubal obstructive infertility.

The utilization of chitosan/Bletilla striata hydrogels to elevate anti-adhesion,anti-inflammatory and pro-angiogenesis properties of polypropylene mesh in abdominal wall repair

Polypropylene(PP)mesh is commonly used in abdominal wall repair due to its ability to reduce the risk of organ damage,infections and other complications.However,the PP mesh often leads to adhesion formation and does not promote functional tissue repair.In this study,we synthesized one kind of aldehyde Bletilla striata polysaccharide(BSPA)modified chitosan(CS)hydrogel based on Schiff base reaction.The hydrogel exhibited a porous network structure,a highly hydrophilic surface and good biocompatibility.We wrapped the PP mesh inside the hydrogel and evaluated the performance of the resulting composites in a bilateral 1×1.5cm abdominal wall defect model in rats.The results of gross observation,histological staining and immunohistochemical staining demonstrated the positive impact of the CS hydrogel on anti-adhesion and wound healing effects.Notably,the addition of BSPA to the CS hydrogel further improved the performance of the composites in vivo,promoting wound healing by enhancing collagen deposition and capillary rearrangement.This study suggested that the BSPA-modified CS hydrogel significantly promoted the anti-adhesion,anti-inflammatory and pro-angiogenesis properties of PP meshes during the healing process.Overall,this work offers a novel approach to the design of abdominal wall repair patches.

An active bacterial anti-adhesion strategy based on directional transportation of bacterial droplets driven by triboelectric nanogenerators

An active bacterial anti-adhesion strategy based on directional transportation of bacterial droplets driven by a triboelectric nanogenerator(TENG)has not been reported to date,although passive defense approaches can prevent bacterial adhesion by regulating superwetting surfaces combined with incorporated antibacterial substances.Here a triboelectric nanogenerator driving droplet system(TNDDS)was built to drive directional transportation of bacterial droplets to be eliminated,which comprises TENG with periodical frictional Kapton film and aluminum foils and a superhydrophobic driving platform(SDP)with paralleled driving electrodes.The current generated by the TENG triboelectricity is transmitted to the paralleled driving electrodes to form an electric field driving the directional transportation of charged droplets.The critical value of the driven droplet volume on SDP is closely related to the distributed electrodes’distance and width,and the driving distance of droplets is related to the number of electrodes.More crucially,TNDDS can actively drive the charged droplets of prepared triangular silver nanoprisms(Ag NPs)forward and back to mix with and remove a tiny bacterial droplet on an open SDP or in a tiny semi-enclosed channel.Bacteria could be killed by releasing Ag+and effectively removed by TNDDS by regulating the motion direction.Generally,this approach offers a promising application for removing bacteria from material surfaces driven by TENG and opens a new avenue for bacterial anti-adhesion.

Progress in the bionic study on anti-adhesion and resistance reduction of terrain machines

The theoretical studies of bionics of machinery have great scientific significance, and the development of bionic machines has large practical values in the field of engineering and technology. Through the rigorous selection process of evolution, the survived living organisms have successfully developed outstanding abilities to adapt to their surroundings and to reproduce their offspring. In this review,we interpreted the fundamental principles of anti-adhesion and anti-resistance of soil animals by reviewing the current status in this research field and summarizing the work of the research group at Jilin University of China in the past decades. The principles and technologies used in morphology bionics,electric-osmosis bionics,flexibility bionics,configuration bionics and coupling bionics were examined.Finally,the applications of the engineering bionics and their extensive prospects were introduced.

Bacterial anti-adhesion surface design:Surface patterning,roughness and wettability:A review

Bacterial adhesion and biofilm formation impose a heavy burden on the medical system. Bacterial adhesion on implant materials would induce inflammation and result in implant failure. The adhesion of bacteria on food-processing and handling equipment may lead to food-borne illness. To reduce and even prevent bacterial adhesion, some bacterial anti-adhesion surface designs have been developed. However,the effect of some surface properties(including surface patterning, roughness and wettability) on bacterial adhesion has not been systematically summarized. In this review, a comprehensive overview of bacterial anti-adhesion surface design is presented. Modifying the surface pattern and roughness could reduce the contact area between bacteria and surfaces to weaken the initial adhesion force. Fabricating superhydrophobic surface or modifying hydrophilic functional groups could hinder the bacterial adhesion. The analysis and discussion about influencing factors of bacterial anti-adhesion surfaces provide basic guidelines on antibacterial surface design for future researches.

A functional PVA aerogel-based membrane obtaining sutureability through modified electrospinning technology and achieving promising anti-adhesion effect after cardiac surgery

Pericardial barrier destruction,inflammatory cell infiltration,and fibrous tissue hyperplasia,trigger adhesions after cardiac surgery.There are few anti-adhesion materials that are both functional and sutureable for pericardial reconstruction.Besides,a few studies have reported on the mechanism of preventing pericardial adhesion.Herein,a functional barrier membrane with sutureability was developed via a modified electrospinning method.It was composed of poly(L-lactide-co-caprolactone)(PLCL)nanofibers,poly(vinyl alcohol)(PVA)aerogel,and melatonin,named PPMT.The PPMT had a special microstructure manifested as a staggered arrangement of nanofibers on the surface and a layered macroporous aerogel structure in a cross-section.Besides providing the porosity and hydrophilicity obtained from PVA,the structure also had suitable mechanical properties for stitching due to the addition of PLCL nanofibers.Furthermore,it inhibited the proliferation of fibroblasts by suppressing the activation of Fas and P53,and achieved anti-inflammatory effects by affecting the activity of inflammatory cells and reducing the release of pro-inflammatory factors,such as interleukin 8(IL-8)and tumor necrosis factorα(TNF-α).Finally,in vivo transplantation showed that it up-regulated the expression of matrix metalloproteinase-1(MMP1)and tissue inhibitor of metalloproteinase-1(TIMP1),and down-regulated the expression of Vinculin and transforming growth factorβ(TGF-β)in the myocardium,thereby reducing the formation of adhesions.Collectively,these results demonstrate a great potential of PPMT membrane for practical application to anti-adhesion.

Simulation and experimental study on drag reduction and anti-adhesion of subsoiler with bionic surface

A new subsoiler with placoid scale microstructure bionic surface was proposed which mimicked shark skin to reduce tillage resistance and soil adhesion during subsoiling cultivation.The contour curves of placoid scale microstructure on shark skin were fitted,and two kinds of bionic subsoiler with continuous and discontinuous microstructures were designed and fabricated,respectively.The effects of different bionic surfaces on tillage resistance were investigated by finite element simulation and experiment.The results indicated that the bionic subsoiler with discontinuous microstructure reduced the horizontal and vertical force by 21.3%and 24.8%,respectively.The subsoiler with discontinuous microstructure surface can prevent the adhesion between the soil and subsoiler surface more efficiently.

Numerical Simulation of Electroosmotic Flow near Earthworm Surface

The electroosmotic flow near an earthworm surface is simulated numerically to further understand the anti soil adhesion mechanism of earthworm. A lattice Poisson method is employed to solve electric potential and charge .distributiorts in the electric double layer along the earthworm surface. The external electric field is obtained by solving a Laplace equation. The electroosmotic flow controlled by the Navier-Stokes equations with external body force is simulated by the lattice Boltzmann method. A benchmark test shows that accurate electric potential distributions can be obtained by the LPM. The simulation shows that the moving vortices, which probably contribute to anti soil adhesion, are formed near earthworm body surface by the nonuniform and variational electrical force.

Peritoneal adhesions after laparoscopic gastrointestinal surgery

Although laparoscopy has the potential to reduce peritoneal trauma and post-operative peritoneal adhesion formation, only one randomized controlled trial and a few comparative retrospective clinical studies have addressed this issue. Laparoscopy reduces de novo adhesion formation but has no efficacy in reducing adhesion reformation after adhesiolysis. Moreover, several studies have suggested that the reduction of de novo post-operative adhesions does not seem to have a significant clinical impact. Experimental data in animal models have suggested that CO2 pneumoperitoneum can cause acute peritoneal inflammation during laparoscopy depending on the insufflation pressure and the surgery duration. Broad peritoneal cavity protection by the insufflation of a low-temperature humidified gas mixture of CO2, N2O and O2 seems to represent the best approach for reducing peritoneal inflammation due to pneumoperitoneum. However, these experimental data have not had a significant impact on the modification of laparoscopic instrumentation. In contrast, surgeons should train themselves to perform laparoscopy quickly, and they should complete their learning curves before testing chemical anti-adhesive agents and anti-adhesion barriers. Chemical anti-adhesive agents have the potential to exert broad peritoneal cavity protection against adhesion formation, but when these agents are used alone, the concentrations needed to prevent adhesions are too high and could cause major post-operative side effects. Anti-adhesion barriers have been used mainly in open surgery, but some clinical data from laparoscopic surgeries are already available. Sprays, gels, and fluid barriers are easier to apply in laparoscopic surgery than solid barriers. Results have been encouraging with solid barriers, spray barriers, and gel barriers, but they have been ambiguous with fluid barriers. Moreover, when barriers have been used alone, the maximum protection against adhesion formation has been no greater than 60%. A recent small, randomized clinical trial suggested that the combination of broad peritoneal cavity protection with local application of a barrier could be almost 100% effective in preventing post-operative adhesion formation. Future studies should confirm the efficacy of this global strategy in preventing adhesion formation after laparoscopy by focusing on clinical end points, such as reduced incidences of bowel obstruction and abdominal pain and increased fertility.

The Concept of Electroosmotically Driven Flow and Its Application to Biomimetics

The concept of electroosmotically driven flow is built around understanding how the ionized particles or fluid are driven to flow by electroosmosis forces. Apart from the major applications of this concept to micro flow control elements which have been explored in parallel with the rapid developments in micro fabrication technologies, the present focus is on its application to biomimetics. As soil animals (in fact all living creatures) such as earthworms and dung beetles carry bioelectricity, the relative movement between the creatures and the surrounding soil which is a multi-component medium with moist content will generate electrophoresis or electroosmosis forces. Such forces drive the ionized moist content, normally water, to migrate from positive to negative poles under the action of electric double layer (EDL) effect, and effectively reduce the adhesion or drag.Predicting the electroosmotically driven flow in the vicinity of biological and animal surfaces is a key problem of drag/adhesion reduction and biomimetics design. The aim of this article is to demonstrate how the theory of electroosmotically driven flow has developed and to describe its broader significance for anti adhesion of soil animals and biomimetics design of soil machinery tools.

Inhibitory effect of dimeric β peptide on the recurrence and metastasis of hepatocellular carcinoma in vitro and in mice

AIM:To block the adhesion of tumor cells to the extra- cellular matrix, and prevent tumor metastasis and recur- rence, the dimer of the β peptide (DLYYLMDLSYSMKG- GDLYYLMDLSYSMK, β2) was designed and synthesized and its anti-adhesion and anti-invasion effects on hepa- tocellular carcinoma cells were assessed. Additionally, its influence on the metastasis and recurrence of mouse hepatocellular carcinoma was measured. METHODS:The anti-adhesion effect of β2 on the highly metastatic hepatocellular carcinoma cell line HCCLM6 cells and fibronectin (FN) was assayed by the MTT as- say. The inhibition of invasion of HCCLM6 cells by β2 was observed using a Transwell (modified Boyden chamber) and matrigel. Using the hepatocellular carcinoma metas- tasis model and LCI-D20 nude mice, the influence of β2 on the metastasis and recurrence of hepatocellular carci- noma after early resection was investigated. RESULTS:HCCLM6 cells co-incubated with 100 mmol/L, 50 mmol/L, 20 mmol/L or 10 mmol/L β2 for 3 h showed an obvious decrease in adhesion to FN. The adhesion inhibition ratios were 11.8%, 21.7%, 29.6% and 48.7%, respectively. Additionally, HCCLM6 cells cultured with 100 mmol/L β2 had a dramatic decrease in cell invasion. β2 was also observed to inhibit the incisal edge recur- rence and the distant metastasis of nude mice hepato- cellular carcinoma after early resection (P < 0.05). CONCLUSION:The β2 peptide can specifically block the adhesion and invasion of HCCLM6 cells, and can inhibit HCC recurrence and metastasis of LCI-D20 model pos-thepatectomy in vivo. Thus, β2 should be further studied as a new anti-tumor drug.

Fabrication of anti-fouling polyamide nanofiltration membrane by incorporating streptomycin as a novel co-monomer

Polyamide(PA)thin-film composite(TFC)na nofiltration(NF)membrane has extremely broad application prospects in separation of monovalent/diva lent inorganic salts mixed solutio n.However,membrane fouling is the main obstacle to the application of PA,TFC and NF membrane.Streptomycin(SM)is a hydrophilic antibiotic containing a large number of hydroxyl and amino groups.In this work,the NF membrane was prepared via interfacial polymerization(IP)between trimesoyl chloride(TMC)in the organic phase and SM/piperazine(PIP)mixture in the aqueous phase.The NF membrane structure and performance were characterized in detail.The results showed that SM successfully participated in the IP.The negative charge and hydrophilicity of membrane surface were improved.The prepared membrane exhibited good anti-adhesion and anti-bacterial performance,Additionally,when the SM concentration was 2%,the prepared membrane exhibited the optimal permselectivity.The water permeance was 89.4L·m^(-2)·h^(-1)·MPa^(-1).The rejection of NaCl and Na_(2)SO_(4) were 17,17%and 97.84%,respectively.The NaCl/Na_(3)SO_(4) separation factor of the SM2-PIP/TMC membrane in 1000 mg·L^(-1) NaCl and 1000 mg·L^(-1)Na_(2)SO_(4) mixed solution was 40,which was 3.3 times that of PIP/TMC membrane.It indicated that SM2-PIP/TMC demonstrated excellent monovalent/divalent salts separation performance.This work provided an easy and effective approach to preparing anti-fouling NF membrane while possessing superior monovalent/divalent salts separation performance.

The Ciliate Protist <i>Tetrahymena pyriformis</i>as a Cellular Adhesion Model for the Pathogenic Bacterium <i>Staphylococcus aureus</i>

Staphylococcus aureus is one of the main pathogenic agents responsible for nosocomial and community-acquired bacterial infections. The pathogenicity of this Gram-positive bacterium is ensured by its different adhesion factors. Collagen and the extracellular glycoprotein adhesin are among the Staphylococcus most important virulence factors. It has been shown that most of the S. aureus strains carry the ica operon, responsible for biofilm production. However, the coexpression of the icaA and the icaD genes is necessary for complete biofilm synthesis. The aim of our study was to study a collection of 15 clinical strains of S. aureus from different sources for the presence of can and icaD genes coding intercellular adhesion proteins. We also intended to estimate the strains’ ability to form biofilms by the red Cong method and to test the adhesion ability of S. aureus to the ciliated protist Tetrahymena pyriformis, which we used as a novel cellular adhesion model. Finally, we checked the adhesion’s inhibition capacity of some plants extracts. The molecular detection of adhesion genes revealed that 80% of strains are cna positive, and 73% are icaD positive. Qualitative biofilm production of S. aureus revealed that 66.6% of strains were slime producers. The adhesion test revealed that 20% of strains are strongly adhering to T. pyriformis and that the Clematis cirrhosa extract has an anti-adhering effect of S. aureus to the ciliate T. pyriformis.

Effectiveness of Seprafilm^®in Preventing Adhesions on Repeated Cesarean Sections

Due to the recent advances in assisted reproductive technology therapy and perinatal care, cesarean sections have been increasingly employed. The aim of this study was to elucidate the effectiveness of Seprafilm® in saving time during fetal deliveries and in minimizing the amount of blood loss in cesarean deliveries. In cases of second cesarean section, our results showed that Seprafilm® significantly reduced the fetal delivery time from 7.5 ± 2.8 to 5.4 ± 2.2 min (p = 0.001). The time required for total surgery was shortened from 45.3 ± 10.0 to 39.6 ± 6.5 min (p = 0.003). The blood loss was diminished from 816.4 ± 352.1 to 630.8 ± 255.9 g (p = 0.01). These results demonstrate that Seprafilm® is very effective even in repeated cesarean sections.

Surface Anti-bacterial Adhesion Characteristics of TiO_2-coated PMMA

The anti-bacterial adhesion properties of TiO2-coated polymethyl methacrylate （PMMA） surfaces are investigated systematically. In detail, the adhesion of S. aureus （gram positive） and E. coli （gram negative） to TiO2-coated and uncoated PMMA surfaces are performed by the plate counting method. Afterwards, the adhesion free energy of bacteria on both supporting materials is quantified using the thermodynamic approach of Lifshitz van der Waals and acid/base interactions. The superior anti-adhesion capability of TiO2-coated PMMA is demonstrated when compared to native PMMA, both experimentally and theoretically.

Synthesis of two multivalent lactosides with anti-adhesive activity and their fluorescein-labeled and biotin-labeled derivatives

Adhesion of leukocytes to endothelium plays an important role in inflammation-associated diseases.Our previous studies showed that multivalent lactosides were able to inhibit this process.Using 2-azide-l,3-propandiol and glutamic acid as spacers,we synthesized divalent lactoside An-2 and tetravalent lactoside Gu-4 by means of convergent method.These two compounds displayed high anti-adhesive activity and showed therapeutic effect in rats with severe burn shock.In addition, investigation of the anti-adhesion biological mechanism using labeled compounds YAn-2 and YGu-4 demonstrated that the target of multivalent lactosides was CD11b,theβ2 integrin subunit,on the surface of leukocytes.In this paper,the synthesis of these two new multivalent lactosides as well as their fluorescein-labeled and biotin-labeled compounds is reported.

Microbiome-friendly PS/PVP electrospun fibrous membrane with antibiofilm properties for dental engineering

Dental caries is one of the most prevalent and biofilm-associated oral diseases in humans.Streptococcus mutans,with a high ability to form biofilms by adhering to hard surfaces,has been established as an important etiological agent for dental caries.Therefore,it is crucial to find a way to prevent the formation of cariogenic biofilm.Here,we report an electrospun fibrous membrane that could inhibit the adhesion and biofilm formation of S.mutans.Also,the polystyrene(PS)/polyvinyl pyrrolidone(PVP)electrospun fibrous membrane altered the 3D biofilm architecture and decreased water-insoluble extracellular polysaccharide production.Notably,the anti-adhesion mechanism which laid in Coulomb repulsion between the negatively charged PS/PVP electrospun fibrous membrane and S.mutans was detected by zeta potential.Furthermore,metagenomics sequencing analysis and CCK-8 assay indicated that PS/PVP electrospun fibrous membrane was microbiome-friendly and displayed no influence on the cell viability of human gingival epithelial cells and human oral keratinocytes.Moreover,an in vitro simulation experiment demonstrated that PS/PVP electrospun fibrous membrane could decrease colony-forming unit counts of S.mutans effectively,and PS/PVP electrospun fibrous membrane carrying calcium fluoride displayed better anti-adhesion ability than that of PS/PVP electrospun fibrous membrane alone.Collectively,this research showed that the PS/PVP electrospun fibrous membrane has potential applications in controlling and preventing dental caries.

Anti-adhesive Property of Maize Leaf Surface Related with Temperature and Humidity

The anti-adhesive surfaces have always aroused great interest of worldwide scientists and engineers. But in practical ap- plications, it often faces the threat and impact of temperature and humidity. In this work, the excellent anti-adhesive perform- ance of maize leaf under high temperature and humidity were investigated in detail. Firstly, the adhesion forces of the maize leaf surface under different temperature and humidity were measured by using Atomic Force Microscopy （AFM）. The temperature of the substrate was varied between 23 ~C to 100 ~C, and the ambient relative humidity is from 18% to 100%. It was found that the adhesion force of maize leaf decreased with the increase of temperature and humidity. The mechanism of its excellent anti-adhesive performance of maize leaf under high temperature and relative humidity was revealed. The transverse and lon- gitudinal ridges on maize leaf surface interlace with each other, forming small air pockets, which reduces the actual contact area between the object and the maize leaf. With the increase of humidity, the liquid film will be formed in the air pockets gradually and so much water vapor is produced with increase of tempera^tre. Then the air flow rate increases though the wavy top of transverse ridges, inducing the dramatic decrease of adhesion force. Inspired by this mechanism, four samples with this bionic structure were made. This functional ＂biomimetic structure＂ would have potential value in the wide medical equipments such as high frequency electric knife with anti-adhesion surface under high temperature and high humidity.

An overview of functional biolubricants

At present,more and more diseases are associated with the lubrication dysfunction,which requires a systematic study of the complex lubrication behavior of tissues and organs in human body.Natural biomacromolecular lubricants are essential for maintaining ultra-low coefficients of friction between sliding biological interfaces.However,when the surface lubrication performance of tissues or organs destroys heavily,it will bring friction/shear damage for sliding contact interfaces.Therefore,the application of exogenous biological lubricating materials to improve the lubrication situation of damaged tissue or organ interfaces has attracted extensive attention of researchers.In this review,based on a simple summary of lubrication mechanism at sliding biological interface,we systematically introduce the research progress of several kinds of representatively biolubrication materials,including eye drops,tissue anti-adhesion agents,joint lubricants,and medical device lubricants.Meanwhile,the lubrication mechanism and individual advantage and shortcoming for each of these synthetic exogenous lubricated materials are clarified.Correspondingly,the important lubrication application functionality of these biolubricant materials in typically medical surgery scenes,such as dry eye syndrome,tissue adhesion,arthritis,and interventional medical devices,is discussed.Finally,we look forward to the future development direction of artificial biolubricant materials.