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Accelerated biodegradation of iron-based implants via tantalum-implanted surface nanostructures

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Bioactive Materials 2022年第3期7卷 239-250页

作者： Min-Kyu Lee Hyun lee Cheonil Park In-Gu Kang Jinyoung Kim Hyoun-Ee Kim Hyun-Do Jung Tae-Sik Jang Department of Materials Science and Engineering Seoul National UniversitySeoul08826Republic of Korea Querrey Simpson Institute for Bioelectronics Northwestern UniversityEvanstonIL60208USA Department of Biomedical-Chemical Engineering Catholic University of KoreaBucheon14662Republic of Korea Department of Biotechnology The Catholic University of KoreaBucheon14662Republic of Korea Department of Materials Science and Engineering Chosun UniversityGwangju61452Republic of Korea

In recent years,pure iron(Fe)has attracted significant attention as a promising biodegradable orthopedic implant material due to its excellent mechanical and biological properties.However,in physiological conditions,Fe has an extremely slow degradation rate with localized and irregular degradation,which is problematic for practical applications.In this study,we developed a novel combination of a nanostructured surface topography and galvanic reaction to achieve uniform and accelerated degradation of an Fe implant.The target-ion induced plasma sputtering(TIPS)technique was applied on the Fe implant to introduce biologically compatible and electrochemically noble tantalum(Ta)onto its surface and develop surface nano-galvanic couples.Electrochemical tests revealed that the uniformly distributed nano-galvanic corrosion cells of the TIPS-treated sample(nano Ta-Fe)led to relatively uniform and accelerated surface degradation compared to that of bare Fe.Furthermore,the mechanical properties of nano Ta-Fe remained almost constant during a long-term in vitro immersion test(~40 weeks).Biocompatibility was also assessed on surfaces of bare Fe and nano Ta-Fe using in vitro osteoblast responses through direct and indirect contact assays and an in vivo rabbit femur medullary cavity implantation model.The results revealed that nano Ta-Fe not only enhanced cell adhesion and spreading on its surface,but also exhibited no signs of cellular or tissue toxicity.These results demonstrate the immense potential of Ta-implanted surface nanostructures as an effective solution for the practical application of Fe-based orthopedic implants,ensuring long-term biosafety and clinical efficacy.

关键词： Iron Tantalum Ion implantation Biodegradation Orthopedic implants

Outcomes of men aged≤50 years treated with radical prostatectomy:a retrospective analysis

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Asian Journal of Andrology 2019年第2期21卷 150-155页

作者： Byeongdo Song Hakmin lee min Seung lee Sung kyu Hong Department of Urology Seoul National University Bundang HospitalSeongnam 13620Korea Department of Urology Seoul National University College of MedicineSeoul 03080Korea

Previous studies inv estigating prostate can cer(PCa)features in youn ger men have reported con flicting fin dings.This study aimed to investigate pathologic outcomes and biochemical recurrenee(BCR)status in younger men who underwent radical prostatectomy(RP)for PCa.Records of 2057 patients who underwent RP at Seoul National University Bundang Hospital(Seongnam,Korea)between 2006 and 2015 were reviewed;patients were divided according to age into the younger and older groups(men aged50 years,respectively).Postoperative BCR status and functional outcomes and clinicopathologic features were compared betwee n both groups.All an alyses were repeated after propensity score matchi ng.Younger men were more likely to have lowrisk disease(P<0.001),lower pathologic Gleason score(P<0.001)and pathologic stages(P<0.001)than older men.The pathologic Gleason score(P=0.002)and rates of extracapsular extension(P=0.004)were lower in younger men after propensity score matching.In multivariate analysis,age at RP was not an independent predictor of BCR-free survival after RP(P=0.669).Moreover,at 1 year after RP,younger men with preoperative 5?item International Index of Erectile Function score≥22(n=228)showed more favorable results for urinary con tine nee(defi ned as nonuse of pads daily)(99.4%vs 95%,P=0.009)and erections sufficie nt for vaginal in tercourse(81.8%vs 55.5%,P=0.001).Youn ger men had more favorable clinicopathologic features at RP than their older counterparts.Although age was not an independent predictor of BCR status outcome,younger men had better functional outcomes following RP.

关键词： age group prostate cancer prostatectomy

A unique and well-designed 2D graphitic carbon nitride with sponge-like architecture for enhanced visible-light photocatalytic activity

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Journal of Materials Science & Technology 2023年第28期159卷 99-111页

作者： Mahdieh Razi Asrami Milad Jourshabani min Hee Park Daiha Shin Byeong-kyu lee Department of Civil and Environment Engineering University of UlsanDaehakro 93NamguUlsan 680-749Republic of Korea Western Seoul Center Korea Basic Science InstituteSeoul 03759Republic of Korea

A unique and well-designed 2D graphitic carbon nitride(g-CN)with sponge-like architecture has been successfully synthesized by engineering supramolecular self-assembly and well-organized SiO 2 nanoparti-cles.The resulting material showed great optical and textural characteristics with plenty of open and uni-form pores,which are very helpful whether for multiple light scattering or mass transfer.The formation of boosted delocalizedπ-conjugated electrons at the molecular level and condensed heptazine building blocks result in enhanced carrier density and charge transfer dynamics.Optical emission spectroscopy and time-resolved fluorescence lifetime(TRPL)strongly confirmed the enhancement of light harvesting and prolonged charge carrier lifetime.The optimized sample exhibited a degradation performance of 95%of bisphenol A(BPA,10 mg L-1)after 60 min under visible-light irradiation at pH=5.All the scavenging experiments,probing experiments as well as electron paramagnetic resonance(EPR)confirm that•O 2-is the dominant reactive species that fragments bisphenol A.Interestingly,density functional theory(DFT)calculations unveil that the BPA interaction with a modified g-CN containing porous structure is energeti-cally more favorable than non-porous pure g-CN.Moreover,the toxicity assessment showed that the final degradation products were placed in the non-harmful category based on acute and chronic toxicity.This study presents a promising strategy to modify the g-CN properties and provides an efficient technique for boosting its visible-light photocatalytic activity.

关键词： Sponge-like Carbon nitride Photocatalysis Visible-light

Customizable design ofmultiple-biomolecule delivery platform for enhanced osteogenic responses via‘tailored assembly system’

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Bio-Design and Manufacturing 2022年第3期5卷 451-464页

作者： Hyun lee Min-Kyu Lee Ginam Han Hyoun-Ee Kim Juha Song Yuhyeon Na Chang-Bun Yoon SeKwon Oh Tae-Sik Jang Hyun-Do Jung Department of Biomedical-Chemical Engineering Catholic University of KoreaBucheon 14662Republic of Korea Department of Biotechnology The Catholic University of KoreaBucheon 14662Republic of Korea Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Querrey Simpson Institute for Bioelectronics Northwestern UniversityEvanstonIL 60208USA Biomedical Implant Convergence Research Center Advanced Institutes of Convergence TechnologySuwon 443-270Republic of Korea School of Chemical and Biomedical Engineering Nanyang Technological University70 Nanyang DriveSingapore 637457Singapore Department of Advanced Materials Engineering Korea Polytechnic UniversitySiheung-siGyeonggi-do 15073Republic of Korea Surface R&D Group Korea Institute of Industrial TechnologyIncheon 21999Republic of Korea Department of Materials Science and Engineering Chosun UniversityGwangju 61452Republic of Korea

Porous titanium(Ti)scaffolds have been extensively utilized as bone substitute scaffolds due to their superior biocompatibility and excellent mechanical properties.However,naturally formed TiO2 on the surface limits fast osseointegration.Different biomolecules have been widely utilized to overcome this issue;however,homogeneous porous Ti scaffolds could not simultaneously deliver multiple biomolecules that have different release behaviors.In this study,functionally graded porous Ti scaffolds(FGPTs)with dense inner and porous outer parts were fabricated using a two-body combination and densification procedure.FGPTs with growth factor(BMP-2)and antibiotics(TCH)exhibited suitable mechanical properties as bone substituting material and presented good structural stability.The release of BMP-2 was considerably prolonged,whereas the release of TCH was comparable to that of homogenous porous titanium scaffolds(control group).The osteogenic differentiation obtained using FGPTs was maintained due to the prolonged release of BMP-2.The antimicrobial properties of these scaffolds were verified using S.aureus in terms of prior release time.In addition,various candidates for graded porous Ti scaffolds with altered pore characteristics were presented.

关键词： Functionally graded porous titanium scaffold Tailored assembly system Mechanical tunability Multiplebiomolecule delivery Bone tissue engineering

Construction of tantalum/poly(ether imide)coatings on magnesium implants with both corrosion protection and osseointegration properties

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Bioactive Materials 2021年第4期6卷 1189-1200页

作者： Kwang-Hee Cheon Cheonil Park min-Ho Kang In-Gu Kang Min-Kyu Lee Hyun lee Hyoun-Ee Kim Hyun-Do Jung Tae-Sik Jang Department of Materials Science and Engineering Seoul National UniversitySeoulRepublic of Korea Department of Biomedical-Chemical Engineering Catholic University of KoreaBucheonGyeonggi-doRepublic of Korea Institute of Health Science Research Korea UniversitySeoul02841Republic of Korea Department of Materials Science and Engineering Chosun UniversityGwangjuRepublic of Korea

Poly(ether imide)(PEI)has shown satisfactory corrosion protection capability with good adhesion strength as a coating for magnesium(Mg),a potential candidate of biodegradable orthopedic implant material.However,its innate hydrophobic property causes insufficient osteoblast affinity and a lack of osseointegration.Herein,we modify the physical and chemical properties of a PEI-coated Mg implant.A plasma immersion ion implantation technique is combined with direct current(DC)magnetron sputtering to introduce biologically compatible tantalum(Ta)onto the surface of the PEI coating.The PEI-coating layer is not damaged during this process owing to the extremely short processing time(30 s),retaining its high corrosion protection property and adhesion stability.The Ta-implanted layer(roughly 10-nm-thick)on the topmost PEI surface generates long-term surface hydrophilicity and favorable surface conditions for pre-osteoblasts to adhere,proliferate,and differentiate.Furthermore,in a rabbit femur study,the Ta/PEI-coated Mg implant demonstrates significantly enhanced bone tissue affinity and osseointegration capability.These results indicate that Ta/PEI-coated Mg is promising for achieving early mechanical fixation and long-term success in biodegradable orthopedic implant applications.

关键词： Magnesium Tantalum Poly(ether imide) Bio-functionalized coating Biodegradable orthopedic implants

Elucidating Ion Transport Phenomena in Sulfide/Polymer Composite Electrolytes for Practical Solid-State Batteries

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Nano-Micro Letters 2023年第10期15卷 416-432页

作者： Kyeong‑Seok Oh Ji Eun lee Yong‑Hyeok lee Yi‑Su Jeong Imanuel Kristanto Hong‑Seok min Sang‑Mo Kim Young Jun Hong Sang kyu Kwak Sang‑Young lee Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei‑roSeodaemun‑guSeoul 03722Republic of Korea Department of Chemical and Biological Engineering Korea University145 Anam‑roSeongbuk‑guSeoul 02841Republic of Korea School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)50 UNIST‑gilEonyang‑eupUlju‑gunUlsan 44919Republic of Korea Hyundai Motor Company 150Hyundaiyeonguso‑roNamyang‑eupHwaseong‑siGyeonggi‑do 18280Republic of Korea

Despite the enormous interest in inorganic/polymer composite solid-state electrolytes(CSEs)for solid-state batteries(SSBs),the underlying ion transport phenomena in CSEs have not yet been elucidated.Here,we address this issue by formulating a mechanistic understanding of bi-percolating ion channels formation and ion conduction across inorganic-polymer electrolyte interfaces in CSEs.A model CSE is composed of argyrodite-type Li_6PS_5Cl(LPSCl)and gel polymer electrolyte(GPE,including Li~+-glyme complex as an ion-conducting medium).The percolation threshold of the LPSCl phase in the CSE strongly depends on the elasticity of the GPE phase.Additionally,manipulating the solvation/desolvation behavior of the Li~+-glyme complex in the GPE facilitates ion conduction across the LPSCl-GPE interface.The resulting scalable CSE(area=8×6(cm×cm),thickness~40μm)can be assembled with a high-mass-loading LiNi_(0.7)Co_(0.15)Mn_(0.15)O_(2)cathode(areal-mass-loading=39 mg cm~(-2))and a graphite anode(negative(N)/positive(P)capacity ratio=1.1)in order to fabricate an SSB full cell with bi-cell configuration.Under this constrained cell condition,the SSB full cell exhibits high volumetric energy density(480 Wh L_(cell)~(-1))and stable cyclability at 25℃,far exceeding the values reported by previous CSE-based SSBs.

关键词： Solid-state batteries Composite solid-state electrolytes Ion transport phenomena Bi-percolating ion channels Interfacial resistance

Three-dimensional kagome structures in a PCL/HA-based hydrogel scaffold to lead slow BMP-2 release for effective bone regeneration

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Bio-Design and Manufacturing 2023年第1期6卷 12-25页

作者： Se-Hwan lee Kang-Gon lee Jaeyeon lee Yong Sang Cho min-Soo Ghim Soojin Kim Su-Jin Heo Yongdoo Park Young-Sam Cho Bu-kyu lee McKay Orthopaedic Research Laboratory Department of Orthopaedic SurgeryPerelman School of MedicineUniversity of Pennsylvania36th Street and Hamilton WalkPhiladelphiaPA 19104USA Department of Biomedical Sciences College of MedicineKorea University73Goryeodae-roSeongbuk-guSeoul 02841Republic of Korea Medical Device Development Center Daegu-Gyeongbuk Medical Innovation Foundation(K-MEDI hub)80Cheombok-roDong-guDaegu 41061Republic of Korea Department of Mechanical Engineering College of EngineeringWonkwang University460Iksan-daeroIksan 54538Republic of Korea Biomedical Engineering Research Center Asan Institute for Life SciencesAsan Medical Center88Olympic-roSongpa-guSeoul 05505Republic of Korea Department of Mechanical Design Engineering College of EngineeringWonkwang University460Iksan-daeroIksan 54538Republic of Korea MECHABIO Group Wonkwang University460Iksan-daeroIksan 54538Republic of Korea Department of Oral and Maxillofacial Surgery Asan Institute for Life SciencesAsan Medical Center88Olympic-roSongpa-guSeoul 05505Republic of Korea

Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.

关键词： Kagome-structure scaffold Retention capacity Biomimetic hydrogel Bone morphogenetic protein-2(BMP-2)

Effect of Sub-T_g Annealing on the Corrosion Resistance of the Cu–Zr Amorphous Alloys

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Acta Metallurgica Sinica(English Letters) 2018年第3期31卷 273-280页

作者： Sang-Soo Shin Hong-kyu Kim Jae-Chul lee Ik-min Park Department of Materials Science and Engineering Pusan National University Advanced Analysis Center Korea Institute of Science and Technology Department of Materials Science and Engineering Korea University

Despite the economy of material cost and excellent toughness of Cu-based amorphous alloys,especially CusoZrso,their poor corrosion resistance to a chloride medium limits their widespread applications.In this study,corrosion tests were performed on the CusoZrso amorphous alloy with different degrees of short-range order,which were prepared by annealing below the glass transition temperature（Tg）.It was found that the corrosion resistance of amorphous alloys is improved to a significant level when the alloys were heated below Tg.Calorimetric studies showed that thermally activated relaxation process of created disorder,which occurs during sub-Tg annealing,is responsible for the improvement in the corrosion resistance.Molecular dynamics simulations performed on the Cu-Zr amorphous alloys demonstrated that the relaxation process of the alloys is associated with the formation of energetically stable icosahedra and icosahedron-like structures.Our study highlights the effects of sub-Tg annealing on the improvement in the corrosion resistance of the amorphous alloys from the viewpoint the relaxation process of the short-range orders.

关键词： Amorphous alloys Corrosion Annealing Molecular dynamics Electrochemical performance

Colonoscopy procedural skills and training for new beginners

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World Journal of Gastroenterology 2014年第45期20卷 16984-16995页

作者： Seung-Hwa lee Young-kyu Park Duck-Joo lee Kwang-min Kim Center for Health Promotion Ajou University School of Medicine Center for Health Promotion Bundang Jesaeng Hospital

The incidence of colorectal cancer has been increasing in the developed world including South Korea and China.Colonoscopy allows for greater diagnostic specificity and sensitivity compared with other types of examinations,such as the stool occult blood test,barium enema,and computed tomography colonography.Therefore,in recent years,the demand for colonoscopies has grown rapidly.New beginners including primary care physicians may help meet the increasing demand by performing colonoscopies.However,it is a challenge to learn the procedure due to the long learning-curve and the high rate of complications,such as perforation and bleeding,as compared to gastroscopy.Thus,considerable training and experience are required for optimal performance of colonoscopies.In order to perform a complete colonoscopic examination,there were a few important thingsto learn and remember,such as the position of examinee(e.g.,left and right decubitus,supine,and prone)and examiner(two-man method vs one-man standing method vs one-man sitting method),basic skills(e.g.,tip deflection,push forward and pull back,torque,air suction and insufflation),advanced skills(e.g.,jiggling and shaking,right and left turn shortening,hooking,and slide-by technique),assisting skills(e.g.,position change of examinee,abdominal compression,breathing-holding,and liquid-infusion technique),and intubation techniques along the lower gastrointestinal tract.In this article,we attempt to describe the methods of insertion and advancement of the colonoscope to the new beginners including primary care physician.We believe that this article may be helpful to the new beginners who wish to learn the procedure.

关键词： Colonoscopy Beginner Training Proce-dural skills