APPLICATION OF HYALURONIC ACID/SODIUM ALGINATE BASE MICRO-PARTICLES FOR THE PREVENTION OF TISSUE ADHESION IN THE RABBIT MODEL

김재영 차의과학대학교 대학원 2013 국내석사

Purpose : Postsurgical adhesion formation is a significant clinical problem in the field of every surgical specialty. Several adhesion barriers have been developed in forms of solution, film or membrane in an attempt to prevent postsurgical adhesion formation. The purpose of the present study is to compare the efficacy of Hyaluronic acid/Sodium Alginate based micro-particle anti-adhesive agents(MP) for the prevention of postsurgical adhesion formation in a standardized rabbit model. Method : To evaluate the anti-adhesion effect, uterus-abdominal wall abrasion model was adopted in the rabbit. On the surface of injured uterus, two types of anti-adhesive agent, Interceed® and MP, were applied as positive control and study group (each n=10). Neither agents were used in negative control group(n=10). To evaluate acute toxicity, blood sample was drawn at postoperative day 3 and 7 to check the level of inflammation, liver, and kidney function. Three weeks after surgery, the level of adhesion was gradedaccording to Blauer’s scoring system. Histologic evaluation was carried out to estimate tissue reactions at the site of application as well as to assess chronic toxicity for the major organs. Result : The grade of adhesion was significantly lower in the MP compared to those of the negative control. Acute and chronic toxicity induced by this material were not noted in the blood and tissue analysis. Conclusion : This study showed that MP might serve as a novel type resorbable biomaterial to reduce postoperative adhesion. Easy placement and handling of this material make these MP powder potentially successful candidates as a tissue adhesion barrier. 목적 : 수술 후 발생하는 조직 유착은 모든 수술 분야에서 중요한 문제점으로 여겨지고 있다. 이러한 문제를 해결하기 위하여 용액과 필름 및 멤브레인 형태의 제제로 만들어진 유착방지제들이 개발되어 사용되고 있다. 본 연구에서는 가토 조직유착 동물 모델에서 히알루론산/알긴산 (Hyaluronic acid-alginic acid)으로 조성된 미세 입자 형태 유착방지제의 유착 방지 효과 및 체내 안전성을 알아보고자 하였다. 방법 : 유착 방지 효과를 평가하기 위하여 가토를 개복 후 복벽-자궁 찰과상 모델을 만들었다. 음성대조군은 찰과상 유발 후 아무런 처치를 하지 않고 복벽을 닫으며 양성대조군은 Interceed®를, 실험군은 히알루론산/알긴산 미세 입자를 각각 적용 후에 복벽을 닫았다. 실험은 각 군 마다 가토 10예를 사용하여시행하였다. 급성 독성에 대한 평가로 수술 3일째와 7일째에 혈액을 채취하여염증 수치와 간, 신장 기능 수치를 검사하였다. 또한 수술 3주 후에 실험 동물을 희생시킨 후 맹검 상태에서 Blauer’s scoring system에 따라 유착 정도를 확인하였으며 조직학적 검사를 통하여 적용 부위의 조직 반응과 주요 장기에 대한 만성 독성 여부를 확인하였다. 결과 : 유착의 정도는 미세분말입자를 적용한 군에서 대조군과 비교 시 유의하게 낮았으며 급성 및 만성 독성 평가를 위해 시행한 혈액 검사와 조직 검사도 모두 정상이었다. 결론 : 본 연구에서는 히알루론산/알긴산 미세분말입자가 수술 후 조직 유착을 유의하게 감소시키는 새로운 형태의 유착방지제로 사용 될 수 있음을 알 수 있었다. 따라서 미세분말입자 유착방지제는 그 적용과 사용의 편리함으로 인하여 조직 유착 방지에 유용하게 사용될 수 있을 것이라 생각된다. 핵심되는 말 : 유착 방지, 미세분말입자, 히알루론산/알긴산, 가토 모델

Fabrication of a spray-type anti- inflammatory hydrogel and its efficacy as an adhesion barrier

이창엽 서울대학교 대학원 2024 국내석사

Gastrointestinal surgery commonly leads to post-operative adhesions, causing severe complications. To prevent these adhesions, a crucial step is the application of a physical barrier between the peritoneal wall and organs. Despite various adhesion barriers available, some have limitations like off-target placement, complex usage, or prolonged application. This study introduces a novel spray-type adhesion barrier hydrogel that addresses these issues. The barrier, featuring a dual gelation system, forms a polyelectrolyte complex and undergoes gel-sol transition for stability. Remarkably, it remains effective in vivo for over 28 days and exhibits anti-inflammatory properties, which aids the regeneration process by modulating the peritoneal environment. In a rat ischemic button model, the barrier showed immunomodulatory potential by shifting macrophages from M1 to M2 state. In conclusion, this rapid and efficient adhesion barrier shows promise in mitigating post-surgical adhesions. Keyword : Adhesion, Anti-Inflammation, Sprayable Hydrogel, Biocompatible, Rapid Gelation Student Number : 2022-22621 복강 내에서 이루어지는 수술은 흔히 수술 후 유착으로 이어지고, 재수술과 같은 문제점을 야기한다. 유착을 방지하기 위해서는 물리적인 장벽을 복벽과 장기 사이에 세우는 것이 중요하다. 다양한 유착 방지제에도 불구하고, 아직까지도 오프 타겟 현상, 사용의 번거로움, 사용 시간의 장기화 등이 문제가 되고 있다. 이런 문제들에 착안하여 새로운 분사형 유착 방지제 하이드로겔을 개발하는 연구를 진행하였다. 이 유착 방지제는 이중 겔화 구조를 갖고 있으며, 고체 전해질 복합체를 형성 후 액체에서 겔화 된다. 이 하이드로겔은 체내에서 28일 이상 효과를 보이고 항염증성 특징을 띄어 재생 과정에 영향을 미친다. 랫트 허혈성 버튼 모델에서 이 유착 방지제는 면역조절 특징을 보였고, 상처 부위의 대식 세포를 M1에서 M2 형질로 바꾸었다. 결과적으로 이 분사형 하이드로겔은 효과적인 새로운 유착 방지제로서 사용될 잠재력을 보인다.

Evaluation of Thinfilm Adhesion

김종헌 서울대학교 대학원 2016 국내박사

Recently materials are used to artificially bonding the different materials as a conventional single material. Since the interface that is artificially bonding of different materials, relatively weak section than the film and the substrate. So, the most preferentially failure occurs in a variety of external conditions. That is why the adhesion is regarded as the major property in determining the reliability of the product in a thin film system. The study was continued by many researchers to evaluate the quantitative adhesion for a long time, so that a variety of test methods have been developed. However, most of the conventional methods for evaluating adhesion, based on interfacial separation methods and interfacial fracture method, have limitations. There are three important issues in evaluating the quantitative value of adhesion: the first, effect of film/substrate deformation and fracture is important to the adhesion test results. so, it is necessary to re-interpret the results through the analysis of the film and substrate effect. Second, need to accurate measurement of the crack length and area for a few nanometer thickness film. And third, the applicable test method limited by the characteristics of the material. In the case of hard films, fracture or delamination of the film occurs before the interface. For the bending test, film or substrate should be a bending above certain level. In other words, evaluation for very soft materials is possible. In this thesis, in order to overcome the conventional testing method limitations, a new model proposed using the instrumented indentation test(IIT). Instrumented indentation testing (IIT) has recently attracted significant research interest in this connection, since its testing procedure is relatively simple and can be performed locally and above all high load- displacement resolution. Indentation testing at the thin-film system sample may also obtain a load-displacement curve that included the effect the combination of the thin film/substrate and the interface unlike Bulk sample testing. To interpret the load-displacement curve, "Total work of indentation" in the thin-film system was defined the sum of "work of film" and "work of substrate" and "work of adhesion". Using the formulated hardness, modeling for work of film and substrate plastic deformation effect at indentation test condition. Also, assume that relatively soft materials of plastic volume constraint by the hard materials. Constraint plastic zone volume of a relatively soft material by the interface was defined by the interface parameter. The interface parameter derived using the Expanding Cavity Model and interfacial constraint effect. Based on the previous analysis deriving the work of the adhesion excluding the film/substrate deformation effect. The work of adhesion varies with the experimental conditions, it was constraint volume normalization. Finally the adhesion evaluation method using the indentation test was proposed. To verify the validity of the proposed model, compared to indentation test and SAICAS test, a kind of peel test for metal/ceramic based thin film specimens. The results between two methods show good agreement. Those results show that indentation test is effective for estimation of thin-film adhesion.

Synthesis and Performance of Acrylic Pressure Sensitive Adhesives using UV/UV Step-wise Curing System

심규성 서울대학교 대학원 2021 국내박사

점착제는 여러 방면에서 사용이 되며, 산업 전반적으로 적용이 되고 있습니다. Smart device는 여러가지 소재의 적층으로 이루어 지기 때문에 소재 간의 점, 접착은 중요한 화두로 떠오르고 있습니다. 이러한 이유로 점착제의 적용처는 매우 넓게 적용됩니다. 특히 re-usable이라는 특성은 이러한 소재들의 재사용을 위해 문제가 집중되고 있습니다. 본 연구에서는 경화 단계 간의 물성을 조절하고자 하였습니다. UV/UV 경화 기술을 개발하고 이렇게 얻은 아크릴 접착제를 다양한 기술로 특성화 하여 UV/UV step-wise curing을 구현하고자 하였습니다. 1차 경화에서 저압의 UV 광원을 사용하고, 경화 시간으로 경화의 총 에너지를 조절 함으로써, 1차 경화와 2차 경화 사이의 물성의 차이를 넓히도록 하였으며, 3J의 UV를 조사하였을 시 가장 큰 물성의 차이를 보이는 효과를 얻었습니다. UV/UV step-wise curing을 진행함에 있어서, 1차 경화와 2차 경화 사이의 물성 차이를 크게 발현시키기 위해 단량체의 구조 및 반응성의 차이를 이용하여 물성발현을 도모하고자 하였습니다. 선중합체를 중합한 후에 반응을 돕기 위한 methacrylate와 acrylate를 blending하여 물성 변화를 확인 하였습니다. 그러나 단순한 단량체의 blending을 통한 반응성 및 물성 변화는 한계점이 존재 한다는 것을 확인 하였습니다. Methacrylate의 구조적 특성으로 UV의 개시반응은 느리게 시작되나 성장 반응은 높은 것을 확인하였습니다. 단순한 blending 단계에서의 한계점을 확인 했기 때문에, 반응을 진행하는 UV의 광원, 선중합체의 반응성, 다관능기를 갖는 가교제의 함량을 조절하여 1차와 2차 경화 간의 물성차이를 발현시키기 위한 연구를 진행하였습니다. 일반적으로 다관능기는 점착력을 감소시키는 요소로 작용하기 때문에, 이를 적용하기 위해서 intensity가 높은 광원을 사용하였습니다. LED 광원은 단일파장의 광원으로 상대적으로 intensity가 높아서 다관능기의 성장반응이 원활이 진행 되었습니다. 그러나 개시반응이 동시에 발생하여, 충분한 성장을 이루기에는 어려움이 있었습니다. 1차 경화에서는 LED를 사용함이 문제가 있음을 확인하였습니다. 그러나 intensity가 높은 광원을 사용하며 다관능기를 사용할 수 있음을 확인하였습니다. Black light를 통한 1차 경화를 진행하고, 2차 경화에서 LED를 사용한 step-wise curing을 진행 하였습니다. 다관능기를 blending하여 film을 성형하였으며, 5관능기를 blending 한 시편에서 1,2차 경화 간에 가장 큰 물성의 차이를 확인하였습니다. 미경화 가능성을 확인하기 위해 gel-fraction을 측정하였습니다. 대부분의 시편에서는 90%이상의 겔분율을 확인하였습니다. 이는 미경화 부분이 존재하지 않는다 판단 할 수 있습니다. Photo-DSC와 FT-IR를 사용하여 1차 경화 및 2차 경화 간의 경화 margin을 확인하였습니다. Conveyor belt를 사용한 저압 경화에서는 photo-DSC를 통한 경화 거동을 확인 할 수 있었으며, LED를 통한 2차경화에서는 FT-IR을 통한 C=C double bond의 유무를 확인 하였습니다. DMA를 통해 modulus를 확인 하였습니다. 완전 경화가 발생한 경우에 storage modulus의 급격한 증가를 확인 할 수 있었습니다. Storage Modulus의 급격한 증가는 경화가 가능한 C=C 이중결합의 완전한 소모를 의미합니다. Texture Analyzer를 사용하여 점착력의 변화를 확인 하였습니다. 5관능기를 갖는 가교제와 고압을 갖는 LED UV 광원을 사용하였을 때, 가장 큰 점착력의 증가를 보였습니다. 저압에서 구조적인 차이로 경화가 진행되지 못했던 C=C 이중 결합이 고압의 UV를 통해 반응이 진행되어 점착력이 증가하는 현상을 보였습니다. 본 논문에서 연구가 진행되었던 5관능기를 갖는 가교제를 사용함과 동시에 1단계 경화에서는 BL경화를 진행하고, 2단계 경화에서는 LED를 통한 경화를 진행한 step-wise curing은 단계별의 점착력 및 물성의 차이를 발현하였습니다. 이러한 특성은 reworkable 분야에서 적용이 가능 할 것으로 보입니다. Pressure-Sensitive adhesives (PSAs) are used in many fields and are applied throughout the industry. Since smart devices are made up of various materials, the point and adhesion between materials are emerging as important topics. For this reason, the application of adhesives is extensive. In particular, the re-usable property is focused on reusing these materials. In this study, we tried to control the properties between curing stages. We developed UV/UV curing technology and tried to realize UV/UV step-wise curing by characterizing the obtained acrylic adhesive with various technologies. By using a low-pressure UV light source in the first curing and controlling the total energy of curing by curing time, the difference in physical properties between the first curing and the second curing is widened, and the most significant physical property when irradiated with 3J UV I got the effect of showing the difference. In the process of UV/UV step-wise curing, we tried to develop physical properties by using the difference in the structure and reactivity of the monomers to express a massive difference in physical properties between the first and second curing. After the prepolymer was polymerized, methacrylate and acrylate were blended to help the reaction to confirm the change in physical properties. However, it was confirmed that there is a limit to the change in reactivity and physical properties through monomers' simple blending. Due to methacrylate's structural characteristics, it was confirmed that the UV initiation reaction started slowly, but the growth reaction was high. Since the limitations of the simple blending step were identified, a study was conducted to express the difference in physical properties between the primary and secondary curing by controlling the content of the UV light source, the reactivity of the prepolymer, and the content of the crosslinking agent having a polyfunctional group. I did it. In general, polyfunctional groups act as factors that reduce adhesion, so a high-intensity light source was used to apply this. The LED light source is a single wavelength light source and has a relatively high intensity, so the multifunctional group's growth reaction proceeded smoothly. However, since the initiation reaction coincided, it wasn't easy to achieve sufficient growth. It has been confirmed that there is a problem with using LEDs in the first curing. However, it was confirmed that a high-intensity light source could be used, and a multifunctional group can be used. The first curing was performed through black light (BL), and the step-wise curing was performed using LEDs in the second curing. The film was formed by blending multifunctional groups, and the most significant difference in physical properties between the first and second hardening was confirmed in the specimen blended with the five functional groups. Gel-fraction was measured to confirm the possibility of uncuring. In most of the specimens, a gel fraction of 90% or more was confirmed. It can be determined that the uncured part does not exist. Photo-DSC and FT-IR were used to determine the curing margin between the first and second curing. In low-pressure curing using a conveyor belt, the curing behavior was confirmed through photo-DSC, and in the secondary curing through the LED, the presence or absence of C=C double bond through FT-IR was confirmed. The modulus was confirmed through DMA. In the case of complete hardening, a rapid increase in the storage modulus could be observed. The rapid increase in Storage Modulus means complete consumption of the hardenable C=C double bond. The change in adhesion was confirmed using a texture analyzer. When a crosslinking agent having a 5-functional group and an LED UV light source having a high pressure were used, the most significant increase in adhesion was observed. C=C double bonds, which could not be cured due to structural differences at low pressure, reacted through UV at high pressure, increasing adhesion. Using the crosslinking agent with penta-functional groups, which was studied in this paper, the step-wise curing was performed by BL curing in the first stage of curing, and the curing through LED in the second stage of curing. Appeared. This characteristic seems to be applicable in the reworkable industry field.

Reliability Enhancement of Electronics via Mechanical, Thermal, Interfacial Adhesion Testing & Immersion Cooling System Analysis

이승민 서울대학교 대학원 2025 국내박사

Enhancing the reliability of electronic products requires advanced tools and methodologies, particularly in thermal and mechanical interfacial adhesion testing and immersion cooling system reliability analysis. In traditional semiconductor manufacturing, numerous interfaces arise due to multilayered deposition processes, making them susceptible to failures caused by contamination, incomplete processing, temperature variations, or external stresses. Current inspection methods, which rely on image-based techniques or post-fabrication electrical performance tests, lack the capability to identify defects at specific processing stages and fail to provide quantitative assessments of adhesion degradation. To address this, we introduce a quantitative in-line screening tool using time-domain thermoreflectance (TDTR) and its correlation to mechanical adhesion tests. By analyzing changes in thermal transport pathways due to reduced mechanical adhesion, this approach enables early-stage defect detection, reducing production costs, and finally improving yield. Expanding this interfacial adhesion analysis, the study also explores its application in the fabrication of biodegradable electronics, which are increasingly valued for their eco-friendly properties and potential in medical implants. However, conventional methods, such as sacrificial layer assisted transfer printing involves expensive materials, labor-intensive processes, and multiple intermediary steps that undermine their environmental benefits. By leveraging controlled adhesion using octadecyltrichlorosilane (OTS), created on Si/SiO2 surface, a streamlined fabrication method for high-performance biodegradable devices was developed. Interfacial adhesion was precisely controlled by adjusting the OTS packing density, while mechanical and thermal analyses including scratch test and TDTR quantified the interfacial adhesion. This approach enabled photolithography of thin-film metals without delamination and single-step transfer printing onto biodegradable polymer substrates. In addition to adhesion analysis, this study addresses the long-term reliability of immersion cooling systems, which use inert dielectric fluids for data center cooling. Immersion cooling presents a promising solution to improve power usage effectiveness and thermal design power, enhancing cost efficiency in data centers. However, the interactions between prolonged thermal stress, the coolant, and the immersed materials remain underexplored. Through high-temperature accelerated testing, the stability of hydrocarbon-based immersion coolants and their effects on data server components were evaluated. Spectroscopic and thermal analyses revealed accelerated oxidation of the coolant at elevated temperatures, while rheological measurements indicated significant deterioration correlated with oxidation levels. The combined contributions of this study establish interfacial adhesion analysis and immersion cooling system evaluation as indispensable tools for addressing critical challenges in modern electronics. By advancing defect detection, sustainable fabrication of biodegradable devices, and long-term reliability in cooling systems, this research provides transformative potential for improving manufacturing efficiency, sustainability, and device performance in diverse applications.

A New Polymer-Coated Xenogeneic Extracellular Matrix to Prevent Postoperative Adhesion Readily Applicable in the Clinic

김경현 서울대학교 대학원 2026 국내박사

Post-neurosurgical dura reconstruction is crucial for preventing CSF leakage and reducing infection risk. When primary closure is not possible, synthetic and semisynthetic dura substitutes are commonly used, but postoperative adhesions remain a major complication, particularly in reoperations for brain tumors and spinal surgeries. To address this, the use of initiated chemical vapor deposition (iCVD) is investigated to create a polymer-coated dura substitute that minimizes adhesions. iCVD, a dry, solvent-free technique, enables uniform polymer film deposition at low temperatures, ensuring biocompatibility and purity. A widely used dura substitute (Lyoplant) is coated with three biocompatible polymers (pHEMA, EGDMA, V4D4) and assessed cytotoxicity using fibroblasts. Adhesion levels are compared in vitro, and an intracranial adhesion model in mice is used for in vivo evaluation. All polymers exhibit minimal cytotoxicity, with pHEMA showing the least adhesion in vitro and selected for further testing. The uncoated dura causes severe adhesion to the cortex, leading to gross damage, whereas the pHEMA-coated dura prevents adhesion in 90% of cases. Histological analysis reveals inflammatory cell infiltration beneath the uncoated dura. These findings suggest that polymer-coated dura substitutes may reduce reoperation risks and improve patient recovery. Further studies are needed to assess long-term safety for clinical application. 뇌척수 수술에서 수술 후 경막 재건은 뇌척수액(CSF) 누출을 예방하고 감염 위험을 낮추는데 필수적이다. 일차봉합이 불가능한 경우 합성 또는•이종 세포외기질 경막 대체재가 널리 사용되지만, 이로 인한 수술 후 유착이 수술 후 경과를 나쁘게 하거나 재수술을 어렵게 만들기도 한다. 본 연구는 유착을 최소화하기 위한 방안으로 화학 기상 증착법(initiated chemical vapor deposition(iCVD)) 을 이용하여 폴리머 코팅 경막 대체재를 제작하여 시험관내, 생체내•적용을 평가하였다. iCVD는 저온에서 균일한 폴리머 박막을 건식•무용매로 증착할 수 있어 생체적합성과 고순도를 확보할 수 있는 장점이 있다. 상용 경막 대체재(Lyoplant)에 세 가지 생체적합성 폴리머[poly(2-hydroxyethyl methacrylate, pHEMA), ethylene glycol dimethacrylate, EGDMA, 그리고 perfluorodecyl-4-vinyl ether, V4D4]를 코팅하였고, 섬유아세포를 이용해 세포독성을 평가하였다. 또한 in vitro 유착 수준을 비교하고, 생쥐 개두술 유착 모델을 통해 in vivo 효능을 검증하였다. 세 폴리머 모두 최소한의 세포독성을 보였으며, 그 중 pHEMA가 in vitro에서 가장 낮은 유착을 보여 후속 동물실험 대상 폴리머로 선정되었다. 무코팅 경막은 대뇌 피질과의 심한 유착을 유발하여 육안적 뇌손상을 초래한 반면, pHEMA 코팅 경막은 90%의 사례에서 유착을 효과적으로 방지하여 뇌손상을 최소화 하였다. 조직학적 분석에서는 무코팅 경막 하부에서 염증세포 침윤이 관찰되었다. 이상의 결과는 iCVD 기반 폴리머 코팅 경막 대체재가 유착에 의한 재수술 위험을 낮추고 환자 회복을 개선할 잠재력이 있음을 시사한다. 향후 임상 적용을 위해 장기 안전성 및 내구성에 대한 추가 임상연구가 필요하다.

Elucidating the Influence of Surface Treatments, Material Functionalization, and Additives on Adhesion at Buried Interfaces

Andre, John S ProQuest Dissertations & Theses University of Mich 2022 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Adhesion is important to a variety of applications and for a number of industries. Adhesion occurs at buried interfaces and is mediated by interfacial structure. It is difficult to probe buried interfacial structure in situ nondestructively. In this thesis, sum frequency generation (SFG) vibrational spectroscopy was applied to study molecular structures of buried interfaces to understand molecular mechanisms of polymer adhesion at buried interfaces in situ. In addition to the studies of enhancing adhesion of polymer adhesives to substrates, research on a reversible adhesive for polymer recycling and sustainability was also conducted. Soldering flux treatment on copper is an important procedure to ensure bonding of interconnects in an electronic device but can disrupt adhesion of packaging polymers. Chapter 2 reports SFG studies on the effect of model and commercial flux on polymer adhesion. It was found that with surface treatments of the flux treated copper leads to disordered polymer at the buried copper/polymer interfaces, increasing the adhesion. Chemical reactions occurring at the buried interface between two polymers in situ were studied in Chapters 3 and 4. First, the buried ethylene vinyl alcohol (EVOH)/maleic anhydride (MAH) grafted polyethylene (MAHgEO) interface was studied, showing that interfacial chemical reactions occurred, greatly enhancing the adhesion. The chemical reactions can greatly increase adhesion between nylon and MAHgEO was also observed, evidenced by the disappearance of the reactants and appearance of reaction products in the SFG spectra. SFG experiments were also performed to follow the reaction kinetics and measure the activation energy of the interfacial reaction. Chapter 5 studied the influence of an amino silane adhesion promoter on the interfacial structure and adhesion of butyl acrylate/methylmethacrylate copolymers (BAMMAs) incorporated with methyl acrylic acid (MAA) to silica. SFG results elucidated the mechanisms of adhesion enhancement by the adhesion promoter, showing: (1) ionic bonds formed between the tail amine group and acid functionality of BAMMA, (2) migration of more ester C=O groups to the interface with order, and (3) disordered or reduced levels of CH groups at the interface. A self-assembled monolayer (SAM) for debonding adhesives on demand was developed in Chapter 6. The SAM was applied to a silica surface and characterized with SFG and x-ray photoelectron spectroscopy (XPS). Once the SAM was fully prepared, the UV sensitivity was also tested with SFG. Before debonding the UV sensitive group on the SAM, adhesives were applied resulting in an adhesive interface that can be selectively broken. Adhesion tests were performed on silica/adhesive and silica/SAM/adhesive samples before and after UV irradiation exposure, which showed that the debonding could reduce the adhesion strength. SFG has been developed into a powerful tool to characterize interfaces but most of the SFG research has focused on simple model systems. This research demonstrated that SFG can be applied to study many complex polymer interfaces of commercial materials, adding an important technique to the toolbox used to study “real-life” interfaces important to industry. This research showed that for commercial flux, packaging polymers, and polymer resins that disordering, covalent bond formation, and ionic bond formation at buried interfaces could greatly enhance adhesion. This study also reported an easy way to create reversible adhesives, important for recycling. The methods developed in this thesis are generally applicable to study important interfaces of many polymer systems in the future.

연골 세포외기질로 만들어진 막의 항유착성 평가 : Anti-adhesive properties of biofilm made of cartilage extracellular matrix

송보람 아주대학교 2016 국내박사

Adhesion is a phenomenon that takes place when the balance between fibrin deposition and fibrinolysis breaks with chronic inflammation during the wound healing process. Different tissue places are connected between abnormal fibrous bands of scar tissue. While the pathogenesis of adhesion is still unclear, the main mechanism is thought to be inflammatory reactions that stimulate mesothelial layer of tissue. Severe adhesion can hinder physiological activity of involved organs, leading to secondary diseases such as bowel obstruction, pelvic pain, chronic abdominal pain and infertility. Modalities treating these adhesions induce microsurgery, fibrinolytic agents, anticoagulants, anti-inflammatory agents, and drugs such as antibiotics. The most common modality is directly separating adhered tissues using a bioreabsorbable physical barrier. Most barriers, however, act as physical barriers without biological effects. In case of natural polymer derived barriers, it is rapidly degraded before the end of the healing process. Barriers composed of synthetic polymers have the limitation of requiring implant removal. Although the cross-linking of the natural material and drug release systems has been explored to overcome limitation of previous materials, they still fall short of clinically preventing adhesion. In previous studies, we confirmed that the cartilage extracellular matrix is a biocompatible and antiangiogenic functional, and available as a physical barrier to block the movement of the cells. In this study, we expected that extracellular matrix membrane can suppress the postsurgical adhesions by inhibiting the cell adhesion through the surface modification CHAPTER I: In this experiment, we saw how the cartilage extracellular matrix (CEM) affects the activity of the endothelial cells during angiogenesis in vitro. Cartilage extracellular matrix (CEM) inhibited endothelial cells (ECs) adhesion when compared to small intestinal submucosa (SIS). Concentration dependent inhibition of EC attachment was observed in the CEM, while EC attachment and cytoskeleton formation was observed in all concentration in the SIS group. Decrease in cell proliferation was also observed in the CEM group. CEM also interfered with tube formation when compared to SIS during matrigel plug assay. The mode of action during inhibition of tube formation was not due to physical properties of the powder, but rather due to biological component of CEM such as chondroitin sulfate. CHAPTER II: The surface of membrane was modified with PLL coating (PLL 10), thereby neutralizing its surface charge. The PLL10 CEM suppressed fibroblast and endothelial cell adhesion in vitro and moreover, inhibited abdominal adhesion in vivo. This study demonstrates that PLL10 surface modification renders the charge of neutral polymer extracellular matrix surface, thereby inhibiting cell and tissue adhesion. Furthermore, this study suggests a means to modify extracellular matrix surfaces to meet specific requirements of target tissue in preventing post-surgical adhesions.

소수성에 따른 박테리아 부착과 이론적 접근법의 적용성 평가

강은진 고려대학교 대학원 2021 국내석사

Bacteria tend to attach and cluster easily to surrounding surfaces to form microbial communities and biofilm. This is a survival strategy used by nearly all bacteria and is known to increase its own viability through the formation of biofilm and spread to the surface. Depending on the field of application, it can be both beneficial and problematic. Therefore, it is important to selectively control microbial adhesion. To do this, studies on the surface properties of bacteria surfaces and material surfaces are needed. This can be used as a basis for research that optimizes or minimizes conditions to form bacterial adhesives. Initial adhesion is affected by various physicochemical factors of both bacteria and surfaces, best known is hydrophobicity and surface charge. The adhesion of four bacterial strains (Escherichia coli EC, Bacillus licheniformis BC, Pseudomonas aeruginosa PS and Staphylococcus aureus SA) to the glass and the Polypropylene(PP) surfaces was investigated. The aim of this study was to evaluate the applicability of the DLVO and XDLVO theory to predict adhesion and study the effect of the hydrophobicity on bacterial adhesion to surfaces. The hydrophobicity of the bacteria and materials was measured using CAM(Contact angle measurement). The hydrophobicity results of water contact angle measurement showed that the BL is relatively hydrophilic than other bacteria. For both materials, this angle was 5° for glass and 88° for PP. It has been demonstrated for use as a hydrophilic/hydrophobic surface experiments. DLVO and XDLVO results showed that bacteria will adhere to the PP surface better than the glass because there is a section where △ G has a negative value in the PP, while the glass has a positive value which means that the bacteria do not adhere well or develop weakly. When prediction results through DLVO and XDLVO theory and adhesion test results were compared, they were matched well with the measurement time except for BL. In the case of BL, it adhered well to PP only in the first 30 minutes, and after that, it adhered to glass more. When the adhesion results are summarized, it can be seen that the hydrophobic bacteria adhere to the hydrophobic surface and the hydrophilic bacteria adhere to the hydrophilic surface better. In this experimental condition, compared to DLVO and XDLVO, there was no significant difference in the prediction, and it was matched well with the adhesion result, so it is considered that there will be no difficulty in predicting which one will be used. DLVO and XDLVO theory is feasible for predicting initial adhesion and controlling the bacterial adhesion which are important in bioprocess, but chemical and biological properties need to be considered to achieve prediction of next stages.

Evaluation of adhesion capacity of Lactobacillus species to intestinal epithelial cells

김지현 전남대학교 2024 국내석사

Probiotics are beneficial bacteria commonly found in the digestive tract and have a variety of properties that may benefit your health. These properties are primarily due to improving digestive health, strengthening the immune system, and enhancing nutrient absorption. The adhesive properties of probiotics play an important role in allowing these microorganisms to colonize the intestines and perform their useful functions. Adhesion helps maintain digestive health by allowing bacteria to become anchored to the barrier surface, giving them an advantage in competition with harmful bacteria. When selecting probiotic strains, attachment ability is suggested to be an important selection criterion, and this ability is mainly studied in in vivo model systems. However, the biological properties of probiotic strains may not always be consistent with their attachment to mucus and epithelial cells. In this study, four lactic acid bacteria were selected among 11 probiotic strains through experiments to assess their adhesion to intestinal mucin and adhesion to HT-29 cells. Among them are Levilactobacillus brevis (L. brevis), Lactiplantibacillus plantarum (L. 67), Ligilactobacillus salivarius (L. salivarius), and Lactobacillus delbrueckii (L. delbrueckii), which exhibited outstanding adhesion ability. Afterwards, I conducted a study on four lactic acid bacteria with excellent adhesion and analyzed the expression of genes related to mucosal adhesion using mRNA expression levels using qPCR. Strains were compared by dividing them into strains cultured with Lactobacillus and mucin, strains cultured with Lactobacillus in HT-29 cells, and strains cultured with Lactobacillus and mucin. MUB · MapA, and EF-Tu were used for the genes of the four strains, and MUC5AC · MUC2, and IL-10 were used for the genes of HT-29 cells. As a result of the experiment, high gene expression was confirmed in strains cultured with mucin. This showed that the four selected species of lactic acid bacteria showing excellent adhesion played a useful role in intestinal interaction and adhesion. Both experiments clearly demonstrate intestinal interactions and adhesion, revealing important similarities between the two experiments. These similarities demonstrate the versatility with which researchers can choose experiments for the purposes of this study and can provide important information regarding the selection and utilization of probiotic strains.