Mussel-inspired Polyglycerol: Synthesis and Versatile Surface Modification

Department of ChemistryThe nonspecific binding of undesirable proteins, cells and microorganisms on material surfaces is one of the major problems in the biomedical fields. The nonspecific binding of these biomolecules can initiate blood coagulation, bacterial infection, inflammatory response and accumulation of organisms onto implanted materials, medical devices and underwater constructions. To inhibit these phenomena, antifouling polymers that prevent the nonspecific binding have been used as a solution. Among the various antifouling polymers, polyglycerol (PG), a promising candidate to substitute the traditional poly(ethylene glycol) (PEG), has attracted much attention with its water solubility, biocompatibility and antifouling effect. In addition, the pendent hydroxyl group allows functionalization and various structural forms via a variety of synthetic pathways. However, the immobilization of polymers onto surface requires a robust anchoring mechanism, which can be applied to various substrates. The catechol group, a key element of adhesive property of mussel renders the surface-independent binding ability and a versatile method to modification of material surfaces. In this study, we designed a new acetonide-protected catechol functionalized glycerol monomer (CAG), which was polymerized by anionic ring opening polymerization. A series of catechol functionalized polymer (PCAG) with various molecular weights (6,000 ? 20,000 g/mol) and catechol contents (0 ? 33%) were synthesized in a controlled manner. The acetonide protection was easily removed by acidic treatment and free catechol group was revealed. The immobilization of PCAG on various surfaces would offer the versatile surface modification method. Beyond that, the relationship between antifouling effect and its size, composition and architecture will be covered. We anticipate that this novel catechol functionalized monomer will be used in various applications in biomedical fields.ope

Synthesis of Mussel-Inspired Functional Materials for Surface Modification

Department of ChemistryMussel enables surface independent wet adhesion with the secretion of mussel foot protein. Mussel foot protein contains a unique amino acid, Dopa, as the key of adhesion. Catechol functional group of Dopa introduces robust and durable adhesion properties, hence, catechol is attracted the intensive interest as a universal anchoring block for surface modification. The catechol-functionalized materials are applied for a wide range of applications such as biomedical, energy storage and environmental applications. In this regard, this thesis describes the synthesis of catechol-functionalized materials and the use of the materials for various applications. This thesis divided into three part(1) catechol-functionalized dental primer, (2) antifouling coating of catechol functionalized polymer (3) wet-adhesion of catechol-amine functionalized polymer. In the first part, the catecholic primer with (meth)acrylate group was synthesized. The catecholic primers effectively crosslink the glass substrate and polymer-based resin matrix with a simple drop-casting method. The composite resin containing the catecholic primers exhibited improved mechanical properties comparable with commercial silane primers. The second part introduced catechol-functionalized block copolymer initiated by polyethylene glycol (PEG). The catechol anchoring block offers a binding ability to substrate while PEG shows antifouling effect. The antifouling effect according to the various composition and conformation was studied using quartz crystal microbalance. (QCM) and surface force apparatus (SFA). Finally, the wet-adhesion of Dopa and lysine of mussel foot protein was translated to polyether system. The protected catechol and azide functionalized epoxide were synthesized and copolymer was prepared with different composition. The surface interaction of copolymers was investigated by SFA to reveal the synergistic adhesion of catechol and amine.clos

Mussel-Inspired Polyglycerols: Synthesis and Versatile Surface Modification

The nonspecific binding of undesirable proteins, cells and microorganisms on material surfaces is one of the major problems in the biomedical fields. The nonspecific binding of these biomolecules can initiate blood coagulation, bacterial infection, inflammatory response and accumulation of organisms onto implanted materials, medical devices and underwater constructions. To inhibit these phenomena, antifouling polymers that prevent the nonspecific binding have been used as a solution. Among the various antifouling polymers, polyglycerol (PG), a promising candidate to substitute the traditional poly(ethylene glycol) (PEG), has attracted much attention with its water solubility, biocompatibility and antifouling effect. However, the immobilization of polymers onto surface requires a robust anchoring mechanism, which can be applied to various substrates. The catechol group, a key element of adhesive property of mussel renders the surface-independent binding ability and a versatile method to modification of material surfaces. In this study, we designed a new acetonide-protected catechol functionalized glycerol monomer (CAG), which was polymerized by anionic ring opening polymerization. A series of catechol functionalized polymer (PCAG) with various molecular weights and catechol contents were synthesized in a controlled manner. The acetonide protection was easily removed by acidic treatment and free catechol group was revealed. The immobilization of PCAG on various surfaces would offer the versatile surface modification method. Beyond that, the relationship between antifouling effect and its size, composition and architecture will be covered. We anticipate that this novel catechol functionalized monomer will be used in various applications in biomedical fields

Redox-degradable biocompatible hyperbranched polyglycerols: Synthesis, copolymerization kinetics, degradation, and biocompatibility

Polymers that are biocompatible and degrade in response to stimuli are highly desirable as smart drug-delivery carriers. We report the first novel redox-degradable hyperbranched polyglycerols. A glycerol monomer containing a disulfide bond, i.e., 2-((2-(oxiran-2-ylmethoxy)ethyl)disulfanyl)ethan-1-ol (SSG), was designed and polymerized through anionic ring-opening multibranching polymerization to yield a series of redox-degradable hyperbranched polyglycerols (PSSGs) with controlled molecular weights (2000-11 000 g/mol) and relatively low molecular weight distributions (Mw/Mn < 1.15). In addition, copolymerization with a nondegradable glycerol (G) monomer provided P(G-co-SSG) copolymers, which contained an adjustable fraction of degradable moieties within their polyglycerol backbones. The polymerization was characterized using 1H and 13C NMR spectroscopy, GPC, and MALDI-ToF mass spectrometry. The copolymerization process was also evaluated using quantitative in situ 13C NMR kinetic measurements in bulk, which revealed that the reaction kinetics of G were faster than those of the SSG monomer, leading to a gradient during the copolymerization process. Furthermore, we explored the redox-responsive degradation of the polymers upon treatment with a reducing agent, which resulted in selective degradation of the polymers in small segments. In vitro cytotoxicity studies, such as MTT and CCK-8 assays, revealed the superior biocompatibility of these new polymers even at high concentrations of 500 ??g/mL. We anticipate that these novel redox-degradable and highly biocompatible polyglycerols will find applications in a variety of emerging biomedical fields.close2

Light-Responsive Micelles of Spiropyran Initiated Hyperbranched Polyglycerol for Smart Drug Delivery

Light-responsive polymeric micelles have emerged as site-specific and time-controlled systems for advanced drug delivery. Spiropyran (SP), a well-known photochromic molecule, was used to initiate the ring-opening multibranching polymerization of glycidol to afford a series of hyperbranched polyglycerols (SP-<i>hb</i>-PG). The micelle assembly and disassembly were induced by an external light source owing to the reversible photoisomerization of hydrophobic SP to hydrophilic merocyanine (MC). Transmission electron microscopy, atomic force microscopy, UV/vis spectroscopy, and dynamic light scattering demonstrated the successful assembly and disassembly of SP-<i>hb</i>-PG micelles. In addition, the critical micelle concentration (CMC) was determined through the fluorescence analysis of pyrene to confirm the amphiphilicity of respective SP-<i>hb</i>-PG_<i>n</i> (<i>n</i> = 15, 29, and 36) micelles, with CMC values ranging from 13 to 20 mg/L, which is correlated to the length of the polar polyglycerol backbone. Moreover, the superior biocompatibility of the prepared SP-<i>hb</i>-PG was evaluated using WI-38 cells and HeLa cells, suggesting the prospective applicability of the micelles in smart drug delivery systems

Sweet nanodot for biomedical imaging: Carbon dot derived from xylitol

We report a facile microwave pyrolysis approach to prepare carbon dots (CDs) using xylitol, a biomass-derived sugar alcohol. Both the surface-passivating agent (ethylenediamine) and HCl are crucial to control the luminescent properties during the synthesis of CDs. CDxy exhibits bright luminescence, aqueous stability, and low cytotoxicity, and thus has high potential for biomedical applications.close1

Bioinspired Catecholic Primers for Rigid and Ductile Dental Resin Composites

In the construction of dental restorative polymer composite materials, surface priming on mineral fillers is essential to improve the mechanical performance of the composites. Here we present bioinspired catechol-functionalized primers (catechol-spacer-methacrylate) for a tougher dental resin composite containing glass fillers. Catecholic primers with different end groups were designed and then coated on glass surfaces using a simple drop-casting or dip-coating process. The surface binding ability and possible crosslinking (coupling or chemical bridging between the glass substrate and the dental resin) of the catecholic bifunctional primers were evaluated using atomic force microscopy, contact angle measurements, and the knife shear bonding test and compared to a state-of-the-art silane-based coupling agent. Various mechanical tests including shrinkage and compression tests of the dental resin composites were also conducted. Compression tests of the composites containing the catecholic primed fillers exhibited enhanced mechanical properties, owing to the bidentate hydrogen bonding of catechol moieties to the oxide mineral surface. Furthermore, the superior biocompatibility of the primed surface was confirmed via cell attachment assay, thus providing applicability of catecholic primers for practical dental and biomedical applications

Bioinspired Catecholic Primers for Rigid and Ductile Dental Resin Composites

In the construction of dental restorative polymer composite materials, surface priming on mineral fillers is essential to improve the mechanical performance of the composites. Here we present bioinspired catechol-functionalized primers for a tougher dental resin composite containing glass fillers. The catecholic primers with different polymerizable end groups were designed and then coated on glass surfaces using a simple drop-casting or dip-coating process. The surface binding ability and possible cross-linking (coupling or chemical bridging between the glass substrate and the dental resin) of the catecholic bifunctional primers were evaluated using atomic force microscopy, contact angle measurements, and the knife shear bonding test and compared to a state-of-the-art silane-based coupling agent. Various mechanical tests including shrinkage and compression tests of the dental resin composites were also conducted. Compression tests of the composites containing the catecholic primed fillers exhibited enhanced mechanical properties, owing to the bidentate hydrogen bonding of catechol moieties to the oxide mineral surface. Furthermore, the superior biocompatibility of the primed surface was confirmed via cell attachment assay, thus providing applicability of catecholic primers for practical dental and biomedical applications

Bioinspired catecholic primers for rigid and ductile dental resin composites

In the construction of dental restorative polymer composite materials, surface priming on mineral fillers is essential to improve the mechanical performance of the composites. Here we present bioinspired catechol-functionalized primers for a tougher dental resin composite containing glass fillers. The catecholic primers with different polymerizable end groups were designed and then coated on glass surfaces using a simple drop-casting or dip-coating process. The surface binding ability and possible cross-linking (coupling or chemical bridging between the glass substrate and the dental resin) of the catecholic bifunctional primers were evaluated using atomic force microscopy, contact angle measurements, and the knife shear bonding test and compared to a state-of-the-art silane-based coupling agent. Various mechanical tests including shrinkage and compression tests of the dental resin composites were also conducted. Compression tests of the composites containing the catecholic primed fillers exhibited enhanced mechanical properties, owing to the bidentate hydrogen bonding of catechol moieties to the oxide mineral surface. Furthermore, the superior biocompatibility of the primed surface was confirmed via cell attachment assay, thus providing applicability of catecholic primers for practical dental and biomedical applications.OAIID:RECH_ACHV_DSTSH_NO:T201800275RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A078017CITE_RATE:8.097DEPT_NM:치의학과EMAIL:[email protected]_YN:YN