Anti-adhesive Properties Research Articles

Biomaterials coated with zwitterionic polymer brush demonstrated significant resistance to bacterial adhesion and biofilm formation in comparison to brush coatings incorporated with antibiotics

A critical problem with the use of biomaterial implants is associated with bacterial adhesion on the surface of implants and in turn the biofilm formation. Among different strategies that have been reported to resolve this dilemma, surface design combined with both antiadhesive and antimicrobial properties has proven to be highly effective. Physiochemical properties of polymer brush coatings possess non-adhesive capability against bacterial adhesion and create a niche for further functionalization. The current study aims to evaluate the effect of antibiotics incorporated into the polymer brush on bacterial adhesion and biofilm formation. Brushes made of zwitterionic polymers were synthesized, functionalized with vancomycin via both physical and chemical conjugation, and grafted onto the silicon rubber surfaces. Antibacterial and antiadhesive measurements of designed coated biomaterials were mediated through the use of a parallel plate flow chamber against biofilm growth developed by Staphylococcus aureus and Escherichia coli over a period of 24 h. The analysis of biofilm growth on designed coated biomaterials showed that the pristine coated zwitterionic brushes are significantly resistant to bacterial adhesion and biofilm formation but not in the polymer brush coating incorporated with antibiotics.

Comparative evaluation of the effect of 2% graphene oxide and 5% hydroxyapatite nanoparticles in isolation and in combination on micro tensile bond strength of 5th generation adhesive

Graphene is the thinnest, strongest, and stiffest imaginable material. The biocompatible property of graphene oxide can initiate and facilitate cell adhesion, proliferation, and differentiation of periodontal ligament, osteogenic, and oral epithelial cells. Furthermore, the antibiofilm and anti-adhesion properties of graphene oxide in the prevention of dental biofilm infections, dental caries, and dental erosion as well as for implant surface modification and as an anti-quorum sensing agent. Composites are the most often utilized materials for restoration in the field of dentistry due to adhesive resins' improved mechanical and cosmetic properties. To safeguard the dentin and prevent dental cavities, dentin adhesives are utilized to affix hydrophobic resin composites to hydrophilic dentin tissue. Dental adhesives have a harder time adhering to dentin because it contains more water and is less mineralized than enamel. This makes the method more sensitive. As a result, it was chosen to assess and contrast the impact of 5% Hydroxyapatite nanoparticles and 2% Graphene oxide nanoparticles, both separately and together, on the Micro tensile bond strength of 5th generation adhesive. Graphene oxide is the most versatile form of Graphite in structural and functional configuration. Graphene oxide possesses extraordinary physical, chemical, optical, electrical and mechanical properties. Among the graphene family nanomaterials, the reduced form of Graphite adding the oxygenated functional group to the structure increases the surface area and therefore exhibits enviable excellent interaction ability with metal and ions as well as organic species. Graphene oxide in dentistry has provided outstanding results in antimicrobial action, regenerative dentistry, bone tissue engineering, drug delivery, physicochemical properties, enhancement of dental biomaterials and oral cancer treatment.

Expanding the Scope of an Amphoteric Condensed Tannin, Tanfloc, for Antibacterial Coatings.

Bacterial infections are a common mode of failure for medical implants. This study aims to develop antibacterial polyelectrolyte multilayer (PEM) coatings that contain a plant-derived condensed tannin polymer (Tanfloc, TAN) with inherent antimicrobial activity. Tanfloc is amphoteric, and herein we show that it can be used as either a polyanion or a polycation in PEMs, thereby expanding the possibility of its use in PEM coatings. PEMs are ordinarily formed using a polycation and a polyanion, in which the functional (ionic) groups of the two polymers are complexed to each other. However, using the amphoteric polymer Tanfloc with weakly basic amine and weakly acidic catechol and pyrogallol groups enables PEM formation using only one or the other of its functional groups, leaving the other functional group available to impart antibacterial activity. This work demonstrates Tanfloc-containing PEMs using multiple counter-polyelectrolytes including three polyanionic glycosaminoglycans of varying charge density, and the polycations N,N,N-trimethyl chitosan and polyethyleneimine. The layer-by-layer (LbL) assembly of PEMs was monitored using in situ Fourier-transform surface plasmon resonance (FT-SPR), confirming a stable LbL assembly. X-ray photoelectron spectroscopy (XPS) was used to evaluate surface chemistry, and atomic force microscopy (AFM) was used to determine the surface roughness. The LDH release levels from cells cultured on the Tanfloc-containing PEMs were not statistically different from those on the negative control (p > 0.05), confirming their non-cytotoxicity, while exhibiting remarkable antiadhesive and bactericidal properties against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus), respectively. The antibacterial effects were attributed to electrostatic interactions and Tanfloc's polyphenolic nature. This work underscores the potential of Tanfloc as a versatile biomaterial for combating infections on surfaces.

A review on mannosylerythritol lipids and their properties, applications and roles in the circular economy

AbstractMannosylerythritol lipid (MEL) is a microbial surface‐active glycolipid biosurfactant produced by numerous microorganisms. MEL is produced as a major product by Pseudozyma sp. and as a minor product by Ustilago sp. MEL has recently received much practical attention due to its structural diversity, broad biochemical functions, and biocompatibility with the environment. In this review, the production of MEL from various feedstocks, and antimicrobial and antiadhesive properties are discussed. Furthermore, the applications of MEL as an antimicrobial agent in food, moisturizer in cosmetics, as an apoptotic agent in pharmaceuticals, and as a wetting agent in agriculture applications are highlighted. Finally, an overview of MEL production from waste materials presents huge potential for increasing the necessary change to a circular economy.

Zwitterionic carbon quantum dots incorporated ultrafiltration membrane for efficient removal of copper ion

Copper, prized for its excellent thermal and electrical conductivity, poses risks when present in wastewater. Treating copper ion-containing wastewater is vital for human and environmental safety. Membrane separation technology offers an eco-friendly and energy-efficient solution. In this study, a mixture of cellulose acetate (CA) and thermoplastic polyurethane (TPU) was used to fabricate the tubular membrane, with quantum dots (QDs) added. Three types of QDs were introduced into the tubular membrane: carbon quantum dots (CQDs), tertiary amine CQDs (TQDs), and zwitterionic CQDs (ZQDs). At pH = 10, copper ions were chelated with sodium dimethyldithiocarbamate (SDDC) at a ratio of SDDC/Cu2+=10 (w/w), signifying a molar concentration (mol.L-1) ratio of SDDC:Cu2+=3:16. This process achieved a 99.8% removal rate of copper ion. The ZQDs-M exhibited high pure water flux of 6,227.4 L.m−2.h−1.bar−1 and 95.4% copper ion-complex rejection rate. The ZQDs-M also demonstrated excellent anti-adhesion properties, with only 4.55% relative fluorescence intensity of E. coli and 34.58% BSA adsorption. The BSA dynamic anti-fouling property of the ZQDs-M was also superior to that of tubular membrane without QDs addition.

Blue-ringed Octopus inspired slippery coating with physico-chemical synergistic antifouling properties

Bionic superhydrophobic and slippery liquid-infused porous surfaces (SLIPS) have attracted great interest due to their antifouling properties, while the poor stability, complex preparation of porous structures and rapid loss of lubricants, as well as only possessing physical antifouling capability, have hindered their further application. Herein, inspired by the Blue-ringed Octopus’ defensive equipment of slippery skin and toxin secretion when faced with predators, an antifouling slippery coating containing repellent is easily prepared. The repellent capsaicin physically connected to the slippery networks can be activated to accelerate release in response to the changes in pH caused by bacterial secretions, and the adhesion resistance of the coating is improved by 99 % compared to aluminum plates, both conclusions confirmed by experimental and computational data. The anti-adhesive properties of the slippery surface, combined with the repellent properties of capsaicin provides the coating with excellent synergistic physico-chemical antifouling performance. This is demonstrated by the fact that the surface of the coating remains clear after contamination with proteins, bacteria and diatoms, as well as after 65 days of marine field testing. Additionally, the slippery surface has self-healing and outstanding anticorrosion ability. Therefore, the eco-friendly coating has promising application prospects in marine field for antifouling purposes.

Designing a multifunctional TFC membrane with improved permeability and anti-biofouling performance using zwitterionic, quaternary ammonium, and fluorinated materials

A novel copolymer architecture integrating anti-fouling, bactericidal, and fouling-release functions has been developed for thin-film composite (TFC) membranes to effectively address biofouling concerns. The approach involves growing three functional polymers from membrane surface in sequence. The first polymer has low surface energy, the second has bactericidal properties, and the third has a strong hydration capacity. The presence of the multifunctional layer significantly increased water permeability, which is due to the swelling property of the functional polymer. The extended Derjauguin-Landau-Verway-Overbeek (XDLVO) theory analysis shows that the introduction of the multifunctional copolymer architecture increased membrane-foulant total interaction energy (ΔGTOT) from 22.6 to 35.6 mJ/m2, indicating promising anti-adhesive properties. These properties have been confirmed by an 86 % decrease in E. coli adsorption during static bacteria assay. In addition, the fluoropolymer in modified membrane enhances its self-cleaning ability, which has been verified in static fouling-release assays where the TFC membrane can release attached cells under gentle agitation. Our long-term biofouling experiments further confirmed the superior multi-defense properties of the modified TFC membrane. Comparatively, the multifunctional membrane significantly reduced flux decline by 58 % and TOC biomass by 69 % during the dynamic biofouling process, and notably enhanced flux recovery of ∼97 % after cleaning. Our new copolymer architecture highlights the potential to enhance the efficiency and longevity of TFC membranes in a variety of applications.

Efficacy and safety of purified starch for adhesion prevention in colorectal surgery

BackgroundAdhesions within the abdominal cavity develop in as many as 90 % of individuals following abdominal surgery. However, the true adhesive condition of patients can only be ascertained during the second surgery. MethodsWe conducted a prospective, non-randomized study to assess the anti-adhesion properties of purified starch in patients who had undergone colorectal surgery in the past and then needed a subsequent surgical intervention. Adhesion scores have been prospectively recorded in operation notes since January 2020 when patients underwent a second surgery. Patients who had received purified starch during their initial surgery constituted the purified starch group, while those who had not received anti-adhesion medical materials were the control group. The main objectives of the study were to evaluate the extent and severity of adhesions as primary outcomes, while secondary outcomes included measuring blood loss, operation time, and postoperative complications. ResultsWe analyzed the data of 101 patients, with 61 in the purified starch group and 40 in the control group. In multivariate analysis, adhesion severity (Odds ratio, 0.20, 95 % confidence interval 0.08–0.54, P < 0.01) and adhesion area scores (Odds ratio, 0.13, 95 % confidence interval 0.04–0.45, P < 0.01) were significantly lower in the purified starch group than in the control group. There was no significant difference in operation times, blood loss, and postoperative complications between the two groups. ConclusionPurified starch is a safe and effective anti-adhesion material that can significantly reduce the severity and extent of adhesion after colorectal surgery.

Surface modification of FeⅢ-juglone coating on nanofiltration membranes for efficient biofouling mitigation

Nanofiltration membranes have increasingly played a vital role in the purification of surface water and the recycling of wastewater. However, the problem of membrane biofouling, which leads to shortened service life and increased energy consumption, has hindered the widespread application of nanofiltration membranes. In this study, we developed functionalized nanofiltration membranes with anti-adhesive and anti-biofouling properties by coordinating FeIII and juglone onto commercial nanofiltration membranes in a facile and viable manner. Due to the hydrophilic nature of the FeⅢ-juglone coating as well as its ultra-thin thickness and minimal impact on the membrane pores, the permeance of the optimally modified membrane even increased slightly (14 %). The outstanding anti-adhesive property of the FeⅢ-juglone coating was demonstrated by a significant reduction in the adsorption of proteins and bacteria. Furthermore, the modified membranes exhibited lower flux decline amplitude and reduced biofilm deposition during dynamic fouling experiment, further supporting the outstanding anti-biofouling performance of the nanofiltration membrane after the modification with FeⅢ-juglone coating. This study presents a novel and feasible approach for simultaneously improving the water permeance, anti-adhesive property and anti-biofouling property of commercial nanofiltration membranes.

Surface coatings based on chitosan and tannins applied in the in vivo prevention of corn streak disease

The bacterial corn streak disease, caused by Xanthomonas vasicola pv. vasculorum (Xvv) has emerged as a threat to corn production due to its rapid spread and resistance to conventional agrochemicals. Therefore, this study proposes polymeric surface coatings based on chitosan (CS) and tannins (TN) as antimicrobial agents against Xvv. The coatings were formed via the layer-by-layer (LbL) approach on oxidized polystyrene (PS). The coatings increased the wettability and roughness of the surfaces. In vitro assays measuring the minimum inhibitory and minimum bactericidal concentrations (MIC and MBC) demonstrated the antimicrobial activity of CS and TN. Coatings deposited on PS exhibited in vitro anti-adhesive properties against Xvv. The in vitro antimicrobial results were compared with control assays performed with an ionic liquid (IL). The IL was also associated with the polymeric coatings. Polymeric coatings, with or without IL, were deposited on corn leaves for in vivo assays. The IL had no activity against Xvv, and its presence in the CS solution seemed to impair the coating deposition on the corn leaves. However, the in vivo assays confirmed the protective efficacy of the polymeric coatings against Xvv infection, acting as physical barriers. The surface coatings also significantly reduced the Xvv symptoms in infected plants even after the disease spread. These outcomes were attributed to the film-forming ability of CS and TN polymers, the coatings' antimicrobial action, and the LbL efficiency in depositing the coatings on the corn leaves. This study introduces a promising environmentally and economically viable strategy for combating bacterial corn streak disease using biodegradable, cytocompatible natural polymers. The surface coatings offer a sustainable method to address bacterial corn disease, overcoming the limitations of agrochemicals.

Directional transport of drug droplets based on structural and wettability gradients on antibacterial Janus wound plaster with hemostatic, antiextravasation, and prehealing properties

The failure of wound healing is majorly attributed to uncontrolled bleeding and bacterial infections. However, developing a wound plaster that can stop bleeding, resist blood extravasation, and realize directional transportation of drugs to promote wound healing remains a significant challenge. Herein, a superhydrophilic/hydrophobic polyvinyl alcohol/chitosan/silver@Thermoplastic polyurethane (PVA/CS/Ag@TPU) Janus membrane with structural and wettability gradients is developed. In this newly developed membrane, water is absorbed from blood via the superhydrophilic layer, which is attached to the wound, and the charge interactions between platelets and the introduced chitosan (CS) promote blood clotting. The capillary pressure resistance (∆p > 0) of the superhydrophilic layer toward the hydrophobic layer prevents blood permeation, thereby reducing blood loss. The favorable ∆p (< 0) of the membrane based on its structural and wettability gradients can realize the directional transportation of drugs that promote wound healing from the hydrophobic to the superhydrophilic layer. The incorporation of CS and silver endows the Janus membrane with intrinsic antibacterial properties (99.9%). The formation of the hydrated layer on the hydrophilic layer imparts a resisting effect, further endowing the membrane with antiadhesion and antibacterial properties. Experiments involving mice with full-thickness skin wounds revealed that the wound-healing rate increased from 87.65% to ~ 100% when the Janus membrane was loaded with the prehealing drug. Moreover, the dressing accelerated wound healing, regenerated epidermal and granulation tissues, promoted collagen formation, and reduced scar size. Thus, this gradient design strategy opens an avenue for the development of next-generation wound dressings.Graphical abstract

A multifunctional superhydrophobic coating with efficient anti-adhesion and synergistic antibacterial properties

Bacterial adhesion and colonization on the surface present a public health concern worldwide. To address this concern, surfaces are endowed with the ability to resist bacterial adhesion to surfaces and eliminate bacteria. In this study, a multifunctional superhydrophobic antibacterial surface is prepared by combining two composite fillers obtained by in-situ growth of silica nanoparticles on palygorskite via sol-gel and modified by a low surface energy substance and by in-situ reduction of silver nanoparticles via tannic acid and thus adhering to the palygorskite and modified by the low surface energy substance, reducing bacterial adhesion and survival in multiple ways. Firstly, the complex nano/micro structures and low surface energy of the superhydrophobic surface hinder protein adhesion and bacterial adhesion on the surface. Secondly, the sharp surfaces constructed by the nanofibers disrupt bacterial cell integrity, providing physical antibacterial action. Thirdly, the coating releases silver ions and reactive oxygen species, which are produced by silver nanoparticles, to chemically damage bacteria. Through the synergy of superhydrophobic surface and silver nanoparticles, the coating achieves good resistance to bacterial adhesion and is able to eliminate Escherichia coli (100.0 ± 0.1 %) and Staphylococcus aureus (99.8 ± 0.1 %). The coating also exhibits good mechanical properties, with silver ions still being released after 100 cycles of wear test. With its unique self-cleaning, anti-adhesive, anti-corrosion, robust mechanical properties, and antibacterial capabilities, the superhydrophobic coating holds a promising application prospect.

Medical titanium surface-modified coatings with antibacterial and anti-adhesive properties for the prevention of implant-associated infections

Implant-associated infections (IAIs) caused by drug-resistant bacteria remain a critical factor in the failure of implant procedures. Therefore, it is urgent to develop an effective anti-infection coating for implant surface modification to prevent IAIs. Herein, an antibacterial and anti-adhesive coating (CMP-Ti) constructed on the surface of titanium implants is reported, formed by the nanomaterial CeO2@Mn3O4 NRs (CM NRs) with antibacterial activity and the superhydrophilic polymer polyethylene glycol (PEG). The nanocatalyst CM NRs on the surface of CMP-Ti induce ferroptosis-like death of bacteria by catalyzing the production of hydroxyl radical (•OH) and singlet oxygen (1O2) and the consumption of glutathione (GSH). The superhydrophilic coating of CMP-Ti can effectively prevent adherence of drug-resistant bacteria and avoid biofilm formation. By combining the “active offense” antibacterial mechanism with the “passive defense” anti-adhesion mechanism, CMP-Ti can kill bacteria and inhibit biofilm formation. The results of in vivo studies showed that CMP-Ti effectively prevented implant-associated infections caused by Methicillin-resistant Staphylococcus aureus (MRSA), thus promoting tissue repair and osseointegration. Therefore, this multifunctional coating combining “active offense” and “passive defense” provides a promising way to prevent IAIs caused by drug-resistant bacteria and to promote tissue repair in the future.

Evaluating the Potential of Casein Glycomacropeptide in Adult Irritable Bowel Syndrome Management: A Pilot Study.

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects 10-15% of the global population and presents symptoms such as abdominal discomfort, bloating and altered bowel habits. IBS is believed to be influenced by gut microbiota alterations and low-grade inflammation. Bovine kappa-casein glycomacropeptide (GMP), a bioactive dairy-derived peptide, possesses anti-adhesive, prebiotic and immunomodulatory properties that could potentially benefit IBS patients. This pilot study investigated the effects of daily supplementation with 30 g of GMP for three weeks on gut health in five people with IBS. We assessed alterations in gut microbiota composition, fecal and blood inflammatory makers, and gut-related symptoms before, during and after the GMP feeding period. The results revealed no changes in fecal microbiota, subtle effects on systemic and intestinal immune makers, and no changes in gut-related symptoms during and after the GMP supplementation. Further research is needed to assess the potential benefits of GMP in IBS patients, including the examination of dosage and form of GMP supplementation.

Enhanced erosion resistance of HVOF-deposited laser-textured TiC coating with PTFE

ABSTRACT This research explores the enhanced slurry erosion behaviour of a composite coating comprising Titanium Carbide (TiC) deposited via High Velocity Oxy-Fuel (HVOF) spraying process. The study integrates laser texturing and Polytetrafluoroethylene (PTFE) spraying techniques to improve the coating's performance. TiC coating is applied to SS316 substrates using HVOF, followed by laser surface texturing to create micro-scale circular patterns. A thin layer of PTFE is then sprayed onto the textured surface, enhancing static contact angle and anti-adhesive properties. Slurry erosion tests reveal significant improvements in the coating's resistance. The findings offer promising applications in slurry erosion-prone industries. Further investigations aim to study the erosive mechanism of the different samples and evaluate their long-term performance.

In situ modification of ultrafiltration membranes with eco-friendly pyrogallol/taurine to enhance antifouling performance

Fouling is a long-standing problem in water treatment membranes because it substantially deteriorates process efficiency. Here, we present a facile strategy for the in situ modification of polyethersulfone (PES) ultrafiltration (UF) membranes with eco-friendly antifouling materials (i.e., pyrogallol and taurine) to enhance their fouling resistance. When the PES dope solution was immersed into the nonsolvent containing pyrogallol and taurine, the phase separation and surface modification of the PES phase occurred simultaneously. Surface modification with taurine was mediated by pyrogallol, which reacted with taurine to form pyrogallol–taurine complexes. Amphiphilic pyrogallol–taurine complexes were effectively bound to the phase-transitioning PES, resulting in their uniform, dense, and robust deposition throughout the external and internal pore surfaces of the membrane without changing its pore structure. Consequently, the in situ-modified PES membrane exhibited remarkably higher surface hydrophilicity and a more negative charge than pristine PES. Importantly, the proposed in situ modification strategy significantly improved the protein anti-adhesive and antifouling properties of the pristine membrane and enhanced its permeance performance, which cannot be achieved by ex situ modification. Our study provides a facile antifouling strategy that can be applied to various membranes for water purification and desalination and extensively describes the underlying modification mechanism.

Femtosecond laser constructed anti-pollution silica glass surfaces with high-viscosity-oil adhesion prevention

Transparent surfaces with anti-pollution and anti-adhesive properties show promise for optical windows. However, there is currently no effective way to create glass surfaces that are impervious to highly viscous and sticky oils, like crude oil. In this research, an electrical-heating silica glass with resistance to high viscosity oil was prepared using a femtosecond laser process. An inner micro-channel system was fabricated by the femtosecond laser wet etching method, and the surface was treated to be superhydrophilic/underwater superoleophobic through femtosecond laser irradiation. The prepared sample could be electrically heated by its internal heating unit, which could reduce the viscosity of the crude oil. Thus, the prepared sample is resistant not only to typically low-viscosity oils, but also prevents the adhesion of crude oil, which would be widely applied in anti-pollution optical windows.

Synergetic Effects of Nanoscale ALD-HfO2 Coatings and Bionic Microstructures for Antiadhesive Surgical Electrodes: Improved Cutting Performance, Antibacterial Property, and Biocompatibility.

The high temperature induced by surgical electrodes is highly susceptible to severe surface adhesion and thermal damage to adjacent tissues, which is a major challenge in improving the quality of electrosurgery. Herein, we reported a coupled electrode with micro/nano hierarchical structures fabricated by depositing nanoscale hafnium oxide (HfO2) coatings on bionic microstructures (BMs) via laser texturing, acid washing, and atomic layer deposition (ALD) techniques. The synergistic effect of HfO2 coatings and BMs greatly enhanced the hemophobicity of the electrode with a blood contact angle of 162.15 ± 3.16°. Furthermore, the coupled surface was proven to have excellent antiadhesive properties to blood when heated above 100 °C, and the underlying mechanism was discussed. Further experiments showed that the coupled electrode had significant advantages in reducing cutting forces, thermal damage, and tissue adhesion mass. Moreover, the antibacterial rates against Escherichia coli and Staphylococcus aureus were 97.2% and 97.9%, respectively. In addition, the noncytotoxicity levels of HfO2 coatings were verified by cell apoptosis and cycle assays, indirectly endowing the coupled electrode with biocompatibility. Overall, the coupled electrode was shown to have broad potential for application in the field of electrosurgery, and this work could provide new insights into antiadhesion properties under high-temperature conditions.

Nanostructure Explains the Behavior of Slippery Covalently Attached Liquid Surfaces.

Slippery covalently-attached liquid surfaces (SCALS) with low contact angle hysteresis (CAH, <5°) and nanoscale thickness display impressive anti-adhesive properties, similar to lubricant-infused surfaces. Their efficacy is generally attributed to the liquid-like mobility of the constituent tethered chains. However, the precise physico-chemical properties that facilitate this mobility are unknown, hindering rational design. This work quantifies the chain length, grafting density, and microviscosity of a range of polydimethylsiloxane (PDMS) SCALS, elucidating the nanostructure responsible for their properties. Three prominent methods are used to produce SCALS, with characterization carried out via single-molecule force measurements, neutron reflectometry, and fluorescence correlation spectroscopy. CO2 snow-jet cleaning was also shown to reduce the CAH of SCALS via a modification of their grafting density. SCALS behavior can be predicted by reduced grafting density, Σ, with the lowest water CAH achieved at Σ≈2. This study provides the first direct examination of SCALS grafting density, chain length, and microviscosity and supports the hypothesis that SCALS properties stem from a balance of layer uniformity and mobility.

玉米免耕机播种单体防黏土改进设计与试验

When the seeding monomer of no-tillage maize planter operates in sticky and wet soil, soil bonding and blocking of soil-touching parts will occur to different degrees, leading to functional failure and affecting the quality of seeding operation. Aiming to improve the anti-adhesion property with minimum cost, a seeding monomer is modified to operate in sticky and wet soil with the support of TRIZ (Theory of Inventive Problem Solving). There are two major scheme adjustments, including self-cleaning seedbed collating device and split gauge wheel. The Su-field model of seedbed collating device is constructed, and the design scheme of smaller wavy coulter and dirt scraper is proposed on the basis of the standard-solution tool and water-film theory. And the parameters of the wave are determined on account of force analysis of soil particles and bionic earthworm. Based on the systemic-functional analysis of the seeding depth-limiting device and the force analysis of gauge wheel during operation, a split type of depth-gauge wheel with large lug hole is designed. As a result, the field trial demonstrates that the improved monomer could meet the operation requirements of clay soil with the water content of 15%-25%. Compared with the original model, the residual clay content is decreased (seedbed collating device 57.5%, gauge wheel seeding depth-limiting device 10%). This study can provide reference for the anti-adhesion design of soil-contacting parts of agricultural machinery.