Sang Cheon Lee

Kyung Hee University, Sŏul, Seoul, South Korea

Are you Sang Cheon Lee?

Claim your profile

Publications (98)460.6 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this work, we have developed photosensitizer-loaded bubble-generating calcium carbonate (CaCO3)-mineralized nanoparticles that have potential for ultrasound imaging (US)-guided photodynamic therapy (PDT) of tumors. A photosensitizer, chlorin e6 (Ce6)-loaded CaCO3-mineralized nanoparticles (Ce6–BMNs), was prepared using an anionic block copolymer-templated in situ mineralization method. Ce6–BMNs were composed of the Ce6-loaded CaCO3 core and the hydrated poly(ethylene glycol) (PEG) shell. Ce6–BMNs exhibited excellent stability under serum conditions. Ce6–BMNs showed enhanced echogenic US signals at tumoral acid pH by generating carbon dioxide (CO2) bubbles. Ce6–BMNs effectively inhibited Ce6 release at physiological pH (7.4). At a tumoral acidic pH (6.4), Ce6 release was accelerated with CO2 bubble generation due to the dissolution of the CaCO3 mineral core. Upon irradiation of Ce6–BMN-treated MCF-7 breast cancer cells, the cell viability dramatically decreased with increasing Ce6 concentration. The phototoxicity of the Ce6–BMNs was much higher than that of free Ce6. On the basis of tumoral pH-responsive CO2 bubble-generation and simultaneous Ce6 release at the target tumor site, these CaCO3 mineralized nanoparticles can be considered as promising theranostic nanoparticles for US imaging-guided PDT in the field of tumor therapy.
    No preview · Article · Jan 2016 · Journal of Materials Chemistry B
  • [Show abstract] [Hide abstract]
    ABSTRACT: We developed a bone-regenerative scaffold based on systematic combination of porous organic-inorganic hybrid scaffolds and recombinant human parathyroid hormone (rhPTH). The hybrid scaffold was fabricated by immobilization of polyphosphate-functionalized nano-hydroxyapatite (PP-n-HAp) on the surface of porous poly(L-lactic acid) (PLLA) scaffolds, which was followed by rhPTH loading on the polyphosphates of n-HAp surfaces. The surface polyphosphate functionalities of PP-n-HAp enabled the stable chemical immobilization of n-HAp on the amine-treated pore surface of the PLGA scaffolds. rhPTH with a positive charge was bound at a high efficiency of 98.1~99.5% onto the anionic polyphosphates of PP-n-HAp immobilized on PLLA surfaces and was sustainably released for up to 50 days. The release rate was manipulated by adjusting the amount of loaded rhPTH, and the release data were moderately fitted to the Higuchi’s diffusion model. Four types of scaffolds were tested in rabbit calvarias models (PLLA only, PP-n-HAp-PLLA, rhPTH (2 µg) loaded PP-n-HAp-PLLA, and rhPTH (10 µg) loaded PPn- HAp-PLLA). After 5 weeks, rhPTH-loaded PP-n-HAp-PLLA (2 and 10 µg of rhPTH) displayed higher bone growth than the control (PLLA only) group. Nano-HAp and sustained release of rhPTH might be synergistically able to enhance the bone healing in the animal model. © 2015 The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht
    No preview · Article · Nov 2015 · Macromolecular Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate that dual release of bone morphogenic protein-2 (BMP-2) and insulin-like growth factor-1 (IGF-1) by catechol-functionalized adhesive polymer nanoparticles on microgrooved titanium (Ti) surface enhances in vitro osteoblastic differentiation of human mesenchymal stem cells (MSCs). The nanoparticles consisted of three distinct domains, surface Ti-adhesive catechol groups, anionic poly(L-aspartic acid) (PAsp) shells, and hydrophobic poly(L-phenylalanine) (PPhe) cores. The immobilization of the adhesive nanoparticles onto microgrooved Ti surface was verified using various surface analytical tools, such as field-emission scanning electron microscopy (Fe-SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurement. The nanoparticles were immobilized both on the groove bottom surface and the ridge top surface with a similar anchoring density. A fluorescence microscope visualized that BMP-2 and IGF-1 of positive charges were efficiently loaded onto the negatively charged PAsp shells of immobilized nanoparticles. We confirmed the enhanced osteoblastic differentiation of MSCs by presenting the expression results of major osteoblast marker genes and proteins. In addition, overall significant correlations between the experimental results verified the validity of our study. The proposed combined surface of microgrooves and growth factor-releasing nanoparticles can be used as a strong osteogenic promoter on various biomaterial surfaces. Copyright © 2015 Elsevier B.V. All rights reserved.
    No preview · Article · Aug 2015 · Colloids and surfaces B: Biointerfaces
  • [Show abstract] [Hide abstract]
    ABSTRACT: We describe a novel intracellular delivery system based on an apoptotic protein-loaded calcium carbonate (CaCO3)-mineralized nanoparticle (MNP). Apoptosis-inducing cytochrome c (Cyt c)-loaded CaCO3-MNPs (Cyt c-MNPs) were prepared by the block copolymer-mediated in situ CaCO3 mineralization in the presence of Cyt c. The resulting Cyt c-MNPs had a vaterite polymorph of CaCO3 with a mean hydrodynamic diameter of 360.5 nm and exhibited 60% efficiency for Cyt c loading. The Cyt c-MNPs were stable at physiological pH (pH 7.4) and effectively prohibited the release of Cyt c, whereas, at intracellular endosomal pH (pH 5.0), Cyt c release was facilitated. The MNPs enables the endosomal escape of Cyt c for effective localization of Cyt c in the cytosols of MCF-7 cells. Flow cytometry showed that the Cyt c-MNPs effectively induced apoptosis of MCF-7 cells. Our findings indicate that the CaCO3-MNPs can meet the prerequisites for delivery of cell-impermeable therapeutic proteins for cancer therapy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    No preview · Article · Jul 2015 · Chemistry - An Asian Journal
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report a theranostic nanoparticle that can express ultrasound (US) imaging and simultaneous therapeutic functions for cancer treatment. We developed doxorubicin-loaded calcium carbonate (CaCO3) hybrid nanoparticles (DOX-CaCO3-MNPs) through a block copolymer templated in situ mineralization approach. The nanoparticles exhibited strong echogenic signals at tumoral acid pH by producing carbon dioxide (CO2) bubbles and showed excellent echo persistence. In vivo results demonstrated that the DOX-CaCO3-MNPs generated CO2 bubbles at tumor tissues sufficient for echogenic reflectivity under a US field. In contrast, the DOX-CaCO3-MNPs located in the liver or tumor-free subcutaneous area did not generate the CO2 bubbles necessary for US contrast. The DOX-CaCO3-MNPs could also trigger the DOX release simultaneously with CO2 bubble generation at the acidic tumoral environment. The DOX-CaCO3-MNPs displayed effective antitumor therapeutic activity in tumor-bearing mice. The concept described in this work may serve as a useful guide for development of various theranostic nanoparticles for US imaging and therapy of various cancers.
    No preview · Article · Jan 2015 · ACS Nano
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent reports suggest that hypoxia inducible factor-2α (HIF-2α) is a key regulator of osteoarthritis cartilage destruction. However, the precise role of HIF-2α in the inflammatory response and osteoclast differentiation remains unclear. The purpose of this study was to investigate the effect of HIF-2α on inflammatory cytokines, extracellular matrix (ECM) destruction enzymes, and osteoclastic differentiation in nicotine and lipopolysaccharide (LPS)-stimulated human periodontal ligament cells (PDLCs). HIF-2α was upregulated in chronically inflamed PDLCs of periodontitis patients, and in nicotine- and LPS-exposed PDLC in dose- and time-dependent manners. HIF-2α inhibitor and HIF-2α siRNA attenuated the nicotine- and LPS- induced production of NO and PGE2, upregulation of iNOS, COX-2, pro-inflammatory cytokines (IL-1β, TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-11 and IL-17), and matrix metalloproteinases (MMPs; MMP-1, -8, -13, -2 and -9), and reversed the effect on TIMPs (TIMP-1 and -2) in PDLCs. The conditioned medium produced by nicotine and LPS-treated PDLCs increased the number of TRAP-stained osteoclasts, TRAP activity and osteoclast-specific genes, which has been blocked by HIF-2α inhibition and silencing. HIF-2α inhibitor and HIF-2α siRNA inhibited the effects of nicotine and LPS on the activation of Akt, JAK2 and STAT3, ERK and JNK MAPK, nuclear factor-κB, c-Jun, and c-Fos. Taken together, this study is the first to demonstrate that HIF-2α inhibition exhibits anti-inflammatory activity through the inhibition of inflammatory cytokines and impairment of ECM destruction, as well as blocking of osteoclastic differentiation in a nicotine- and periodontopathogen-stimulated PDLCs model. Thus, HIF-2α inhibition may be a novel molecular target for therapeutic approaches in periodontitis. This article is protected by copyright. All rights reserved
    No preview · Article · Jan 2015 · Journal of Cellular Biochemistry
  • [Show abstract] [Hide abstract]
    ABSTRACT: A calcium carbonate (CaCO3)-mineralized core-shell-corona micelle was evaluated as an intracellular nanocarrier of docetaxel (DTX). The polymer micelle consisting of the poly(ethylene glycol) coronal, the anionic poly(L-aspartic acid) middle shell, and the DTX-loaded hydrophobic poly(L-phenylalanine) core was used as a nanotemplate for CaCO3 mineralization was performed by initial electrostatic localization of calcium ions at the anionic PAsp middle shells, and the subsequent addition of carbonate anions to trigger the growth of CaCO3 around the PAsp middle shells. Even after mineralization, the micelle size and the spherical morphology were maintained. The CaCO3-mineralized micelles exhibited enhanced stability against micelle-disrupting surfactants and the serums. The mineralized CaCO3 layer could suppress DTX release efficiently at extracellular pH (7.4) but dissolve at an intracellular endosomal pH (pH ~ 5.0) to facilitate the DTX release. These results reveal the promising potential of CaCO3-mineralized polymer micelle as a stable and effective nanocarrier system in tumor therapy.
    No preview · Article · Jan 2015 · Macromolecular Research
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To determine the effect of fibronectin (FN)-conjugated, microgrooved titanium (Ti) on osteoblast differentiation and gene expression in human bone marrow-derived mesenchymal stem cells (MSCs). Materials and methods: Photolithography was used to fabricate the microgrooved Ti, and amine functionalization (silanization) was used to immobilize fibronectin on the titanium surfaces. Osteoblast differentiation and osteoblast marker gene expression were analyzed by means of alkaline phosphatase activity assay, extracellular calcium deposition assay, and quantitative real-time PCR. Results: The conjugation of fibronectin on Ti significantly increased osteoblast differentiation in MSCs compared with non-conjugated Ti substrates. On the extracellular calcium deposition assays of MSCs at 21 days, an approximately two-fold increase in calcium concentration was observed on the etched 60-µm-wide/10-µm-deep microgrooved surface with fibronectin (E60/10FN) compared with the same surface without fibronectin (E60/10), and a more than four-fold increase in calcium concentration was observed on E60/10FN compared with the non-etched control (NE0) and etched control (E0) surfaces. Through a series of analyses to determine the expression of osteoblast marker genes, a significant increase in all the marker genes except type I collagen α1 mRNA was seen with E60/10FN more than with any of the other groups, as compared with NE0. Conclusion: The FN-conjugated, microgrooved Ti substrate can provide an effective surface to promote osteoblast differentiation and osteoblast marker gene expression in MSCs.
    Preview · Article · Jan 2015 · The journal of advanced prosthodontics
  • Il Keun Kwon · Sang Cheon Lee · Yu-Shik Hwang · Jung Sun Heo
    [Show abstract] [Hide abstract]
    ABSTRACT: Oxysterols, oxidized derivatives of cholesterol, are biologically active molecules. Specific oxysterols have potent osteogenic properties that act on osteoprogenitor cells. However, the molecular mechanisms underlying these osteoinductive effects on embryonic stem cells (ESCs) are unknown. This study investigated the effect of an oxysterol combination of 22(S)-hydroxycholesterol and 20(S)-hydroxycholesterol (SS) on osteogenic differentiation of ESCs and the alterations to mitochondrial activity during differentiation. Osteogenic differentiation was assessed by alkaline phosphatase (ALP) activity, matrix mineralization, mRNA expression of osteogenic factors, runt-related transcription factor 2, osterix, and osteocalcin, and protein levels of collagen type IA (COLIA) and osteopontin (OPN). Treatment of cells with SS increased osteoinductive activity compared to the control group. Intracellular reactive oxygen species production, intracellular ATP content, mitochondrial membrane potential, mitochondrial mass, mitochondrial DNA copy number, and mRNA expression of peroxisome proliferator-activated receptor-γ coactivators 1α and β, transcription factors involved in mitochondrial biogenesis, were significantly increased during osteogenesis, indicating upregulation of mitochondrial activity. Oxysterol combinations also increased protein levels of mitochondrial respiratory complexes I-V. We also found that SS treatment increased hedgehog signaling target genes, Smo and Gli1 expression. Inhibition of Hh signaling by cyclopamine suppressed mitochondrial biogenesis and ESC osteogenesis. Subsequently, oxysterol-induced Wnt/β-catenin pathways were inhibited by repression of Hh signaling and mitochondrial biogenesis. Transfection of β-catenin specific siRNA decreased the protein levels of COLIA and OPN, as well as ALP activity. Collectively, these data suggest that lipid-based oxysterols enhance differentiation of ESCs toward the osteogenic lineage by regulating mitochondrial activity, canonical Hh/Gli, and Wnt/β-catenin signaling.
    No preview · Article · Dec 2014 · Biochimica et Biophysica Acta (BBA) - Molecular Cell Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: Over the past few decades, naturally derived biomaterials have been extensively used in tissue engineering and regenerative medicine owing to their biological function, structural support, excellent biocompatibility, and favorable biodegradability characteristics. Traditionally, keratin has been extracted from wool, feathers, horns, and other animal sources for industrial use, and it has also been used as a biomaterial to develop scaffolds, hydrogels, and other forms for biomedical applications. Recently, keratin extracted from human hair has emerged as a fascinating biomaterial, which as a human-derived protein, exhibits excellent biocompatibility, no immune reaction upon transplantation, good cellular interaction activity, and biodegradability. Recent development of well-defined and proficient processes for human hair keratin extraction has led to the fabrication of various types of keratin-based biomaterials, which have been employed in successful approaches for tissue regeneration. The use of human hair keratin-based biomaterials for translational biomedical applications requires better understanding of the molecular properties and biological function of keratin. This review provides a critical summary of molecular characteristics, cellular interactions, various extraction strategies, and recent advances in biomedical applications of human hair keratin that could be used to improve tissue regeneration for regenerative medicine.
    No preview · Article · Aug 2014 · Tissue Engineering and Regenerative Medicine
  • Gi Hyun Choi · Hong Jae Lee · Sang Cheon Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: Front Cover: Resistance to corrosion, excellent biocompatibility, and superb mechanical strength make titanium (Ti) one of most suitable metals to build many medical devices. On page 496, a catechol-functionalized polymer nanoparticle that can spontaneously adhere to Ti surface is developed. The nanoparticle has three domains: i) a hydrophobic biodegradable polymer core, ii) an anionic hyaluronic acid shell that can load positively charged dual osteogenic proteins, and iii) surface-exposed catechol groups. Sang Cheon Lee and colleagues show how this nanoparticle can be adopted for various applications as a good model of surface controlled releasing systems.
    No preview · Article · Apr 2014 · Macromolecular Bioscience
  • Gi Hyun Choi · Hong Jae Lee · Sang Cheon Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: A titanium (Ti)-adhesive nanoparticle is developed as a surface-releasing system for dual osteogenic growth factors. The Ti-adhesive nanoparticle is prepared by self-assembly of a poly(L-lactide-co-glycolide) (PLGA)-grafted hyaluronic acid (HA) copolymer, followed by conjugation of catechol groups on nanoparticle surfaces. The nanoparticles consist of Ti-adhesive peripheral catechol groups, anionic HA shells, and hydrophobic PLGA inner cores. The immobilization of the nanoparticles onto Ti substrates is successfully verified using various analytical tools including field-emission scanning electron microscopy (Fe-SEM), contact angle measurement, and X-ray photoelectron spectroscopy (XPS). Positively charged dual growth factors, bone morphogenetic protein-2 (BMP-2) and insulin-like growth factor-1 (IGF-1) are readily loaded onto the negatively charged HA shells of surface-immobilized nanoparticles, which is confirmed by fluorescence microscopy. The Ti substrates with dual growth factor-loaded nanoparticle-immobilized nanoparticles remarkably promote the attachment, proliferation, spreading, and alkaline phosphatase (ALP) activity of human adipose-derived stem cells (hADSCs).
    No preview · Article · Apr 2014 · Macromolecular Bioscience
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report on pH-responsive core-shell polymer micelles with catechol-Fe(3+) coordinated core cross-links, which provide robustness to drug-loaded polymer micelles and allow the facilitated intracellular release of loaded anticancer drugs in response to an endosomal acidic pH.
    No preview · Article · Mar 2014 · Chemical Communications
  • [Show abstract] [Hide abstract]
    ABSTRACT: The surface of a polymeric nanoparticle (NP) is often functionalized with cell-interactive ligands and/or additional polymeric layers to control NP interaction with cells and proteins. However, such modification is not always straightforward when the surface is not chemically reactive. For this reason, most NP functionalization processes employ reactive linkers or coupling agents or involve pre-functionalization of the polymer, which are complicated and inefficient. Moreover, pre-functionalized polymers can lose the ability to encapsulate and retain a drug if the added ligands change chemical properties of the polymer. To overcome this challenge, we use dopamine polymerization as a way of functionalizing NP surfaces. This method includes brief incubation of the pre-formed NPs in a weak alkaline solution of dopamine, followed by secondary incubation with desired ligands. Using this method, we have functionalized poly(lactic-co-glycolic acid) (PLGA) NPs with three representative surface modifiers: a small molecule (folate), a peptide (Arg-Gly-Asp), and a polymer [poly(carboxybetaine methacrylate)]. We confirmed that the modified NPs showed the expected cellular interactions with no cytotoxicity or residual bioactivity of dopamine. The dopamine polymerization method is a simple and versatile surface modification method, applicable to a variety of NP drug carriers irrespective of their chemical reactivity and the types of ligands.
    No preview · Article · Mar 2014 · ACS Nano
  • [Show abstract] [Hide abstract]
    ABSTRACT: This chapter summarizes the current preparation processes of various theranostic nanoparticles at a lab scale and the scaling-up methods, and the corresponding pilot plants of each nanoparticle production are discussed. The synthetic and purification methods for some current nanoparticle systems are listed. As examples for scaling-up processes, the construction for pilot plants for drug-loaded polymer nanoparticles based on emulsion-solvent diffusion and nanoprecipitation methods are introduced. In addition, the scale-up process for inorganic iron oxide nanoparticles are described. The parameters that need to be considered for scaling-up processes are listed and applied to the design of plant batches for theranostic nanoparticles. Of the many nanoparticles, polymer-assembled nanoparticles including polymer micelles and polymer nanoaggregates, gold nanoparticles, and iron oxide nanoparticles are selected as model nanoparticles because they have been used as major nanoparticles for theranostic applications. The plant design for each nanoparticle is suggested based on the synthetic and preparation process used for a lab-scale production. Considerations that can overcome the hurdles of theranostic nanoparticles for large-batch productions are also discussed.
    No preview · Article · Mar 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Calcium phosphate-reinforced photosensitizer-loaded polymer nanoparticles have been developed for photodynamic therapy. Chlorin e6 (Ce6)-loaded core-shell-corona polymer micelles of poly(ethylene glycol)-b-poly(L-aspartic acid)-b-poly(L-phenylalanine) (PEG-PAsp-PPhe) were employed as template nanoparticles for mineralization with calcium phosphate (CaP). CaP deposition was performed by the electrostatic localization of calcium ions at the anionic PAsp middle shells and the subsequent addition of phosphate anions. CaP-reinforced nanoparticles exhibited enhanced stability. The CaP mineral layer effectively inhibited Ce6 release from the Ce6-loaded mineralized nanoparticles (Ce6-NP-CaP) at physiological pH value. At an acidic endosomal pH value of 5.0, Ce6 release was enhanced, owing to rapid dissolution of the CaP minerals. Upon irradiation of Ce6-NP-CaP-treated MCF-7 breast-tumor cells, the cell viability dramatically decreased with increasing irradiation time. The phototoxicity of Ce6-NP-CaP was much higher than that of free Ce6. Non-invasive optical-imaging results indicated that Ce6-NP-CaP exhibited enhanced tumor specificity compared with free Ce6 and Ce6-loaded non-mineralized polymer nanoparticles (Ce6-NP).
    No preview · Article · Dec 2013 · Chemistry - An Asian Journal
  • Source
    Dong Jin Park · Sang Jin Lee · Sang Cheon Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: Mucoadhesive property is the major function as an adhesive for medical devices, and therefore, these days many researches have conducted to develop polymers having this property. Recently, biomimetic technology has been used for developing mucoadhesive polymers. Among many technologies, mussel-inspired approaches have received noticeable attention because of its thread's strong adhesive characteristics. In this study, we synthesized mucoadhesive biomimetic polymers employing catechol structures which are abundant in mussel adhesive proteins, and their structures and molecular weights were characterized by using nuclear magnetic resonance spectroscopy and gel permeation chromatography. To evaluate in vitro mucoadhesive strength, the sheet type of the small intestinal porcine submucosa was prepared. Compared to commercial fibrin glue adhesives, catechol-containing mucoadhesive polymers showed enhanced adhesive strength. The study of adhesive strength with considering diverse factors, such as temperature, pressure, and oxidant amount indicated that mussel-inspired mucoadhesive polymer could be a promising candidate for an adhesive in various biomedical applications.
    Full-text · Article · Sep 2013 · Polymer Korea
  • [Show abstract] [Hide abstract]
    ABSTRACT: Enhanced drug-loading and therapeutic efficacies are highly essential properties for nanoparticles as tumor-targeting drug carriers. Herein, we developed the glycol chitosan nanoparticles with hydrotropic oligomers (HO-CNPs) as a new tumor targeting drug delivery system. For enhancing drug-loading efficiency of paclitaxel in drug carriers, hydrotropic 2-(4-(vinylbenzyloxy)-N,N-diethylnicotinamide) (VBODENA-COOH) oligomers, that were used for enhancing the aqueous solubility of paclitaxel, were directly conjugated to glycol chitosan polymers. The amphiphilic conjugates readily formed nanoparticle structure (average size=302 ± 22nm) in aqueous condition. Water-insoluble paclitaxel (PTX) was readily encapsulated into HO-CNPs with a high drug-loading amount up to 24.2wt% (2.4 fold higher than other polymeric nanoparticles) by a simple dialysis method. The PTX encapsulated HO-CNPs (PTX-HO-CNPs; average size=343 ± 12nm) was very stable in aqueous media up to 50days. Also, PTX-HO-CNPs presented rapid cellular uptake and lower cytotoxicity in cell culture system, compared to Cremophor EL/ethanol formulation of PTX. In tumor-bearing mice, the extravasation and accumulation of PTX-HO-CNPs in tumor tissue was precisely observed by intravital fluorescence imaging techniques. Furthermore, PTX-HO-CNPs showed the higher therapeutic efficacy, compared to Abraxane®, a commercialized PTX-formulation. These overall results demonstrate its potential as a new nano-sized PTX carrier for cancer treatment.
    No preview · Article · Sep 2013 · Journal of Controlled Release
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on a smart mesoporous silica nanoparticle (MSN) that can trigger the release of anti-inflammatory N-acetyl-L-cysteine (NAC) within the intracellular environment. NAC was conjugated to the pore surfaces of MSNs through glutathione (GSH)-cleavable disulfide linkages. Solid-state nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR) spectroscopy, and Brunauer-Emmett-Teller (BET) analyses confirmed the successful NAC conjugation to the pore walls. The release of NAC from the NAC-conjugated MSN (MSN-NAC) could be controlled by adjusting the concentration of GSH regarding the release media. At an extracellular level of GSH (10 μM), the NAC release was greatly inhibited, whereas, at an intracellular level of GSH (2 mM), MSN-NAC facilitated the release of NAC. Confocal laser scanning microscopy (CLSM) studies showed that the NAC release was effectively triggered by intracellular GSH after uptake by BV-2 microglial cells. The MSN developed in this work may serve as the efficient intracellular carriers of NAC for the treatment of neuroinflammation.
    Full-text · Article · Jul 2013 · Macromolecular Research
  • Hong Jae Lee · Ahn Na Koo · Suk Won Lee · Myung Hyun Lee · Sang Cheon Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on a novel surface functionalization approach to equip the titanium (Ti) surfaces with osteogenic properties. A key feature of the approach is the treatment of the Ti surfaces with Ti-adhesive nanoparticles that can stably load and controllably release bone morphogenetic protein-2 (BMP-2). Ti-adhesive nanoparticles were prepared by self-assembly of a catechol-functionalized poly(amino acid) diblock copolymer, catechol-poly(L-aspartic acid)-b-poly(L-phenylalanine) (Cat-PAsp-PPhe). The nanoparticles consist of Ti-adhesive peripheral catechol groups, anionic PAsp shells, and PPhe inner cores. Field-emission scanning electron microscopy (Fe-SEM) images showed that the Ti-adhesive nanoparticles could be uniformly immobilized on Ti surfaces. X-Ray photoelectron spectroscopy (XPS) confirmed the successful anchoring of nanoparticles onto Ti surfaces. After surface immobilization of the nanoparticles, the static water contact angle of the Ti substrate decreased from 75.3° to 50.0° or 36.4°, depending on the surface nanoparticle. Fluorescence microscopic analysis showed that BMP-2 could be effectively incorporated onto the Ti surface with adhesive nanoparticles. BMP-2 was controllably released for up to 40 days. The Ti substrate functionalized with BMP-2-incorporated nanoparticles significantly promoted attachment, proliferation, spreading, and alkaline phosphatase (ALP) activity of human adipose-derived stem cells (hADSC). The catechol-functionalized adhesive nanoparticles may be applied to various medical devices to create surfaces for improved performance.
    No preview · Article · May 2013 · Journal of Controlled Release

Publication Stats

4k Citations
460.60 Total Impact Points


  • 2009-2015
    • Kyung Hee University
      • Department of Dentistry
      Sŏul, Seoul, South Korea
  • 2005-2009
    • Korean Institute of Ceramic Engineering and Technology
      Sŏul, Seoul, South Korea
  • 2003-2008
    • Purdue University
      • Weldon School of Biomedical Engineering
      West Lafayette, Indiana, United States
  • 2007
    • Gyeongsang National University
      Shinshū, South Gyeongsang, South Korea
  • 2004
    • Japan Advanced Institute of Science and Technology
      KMQ, Ishikawa, Japan
  • 1999-2003
    • Inha University
      • Department of Polymer Science and Engineering
      Seoul, Seoul, South Korea
  • 2001
    • Gwangju Institute of Science and Technology
      • School of Materials Science and Engineering
      Gwangju, Gwangju, South Korea
  • 1996
    • Dong-A University
      • Department of Chemistry
      Busan, Busan, South Korea