Enhanced Internalization of Macromolecular Drugs into Mycobacterium smegmatis with the Assistance of Silver Nanoparticles

( Fangfang Sun ),( Sangjin Oh ),( Jeonghyo Kim ),( Tatsuya Kato ),( Hwa-jung Kim ),( Jaebeom Lee ),( Enoch Y. Park ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

In this study, silver nanoparticles (AgNPs) were synthesized by the citrate reduction process and, with the assistance of n-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, were successfully loaded with the macromolecular drug vancomycin (VAM) to form AgNP-VAM bioconjugates. The synthesized AgNPs, VAM, and AgNP-VAM conjugate were characterized by UV-visible spectroscopy, zeta potential analysis, confocal microscopy, and transmission electron microscopy. The effect of loading VAM onto AgNPs was investigated by testing the internalization of the bioconjugate into Mycobacterium smegmatis. After treatment with the AgNP-VAM conjugate, the bacterial cells showed a significant decrease in UV absorption, indicating that loading of the VAM on AgNPs had vastly improved the drug`s internalization compared with that of AgNPs. All the experimental assessments showed that, compared with free AgNPs and VAM, enhanced internalization had been successfully achieved with the AgNP-VAM conjugate, thus leading to significantly better delivery of the macromolecular drug into the M. smegmatis cell. The current research provides a new potential drug delivery system for the treatment of mycobacterial infections.

Biocompatibility of Nanoscale Hydroxyapatite-embedded Chitosan Films

Sun, Fangfang,Koh, Kwangnak,Ryu, Su-Chak,Han, Dong-Wook,Lee, Jaebeom Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

In order to improve the bioactivity and mechanical properties of hydroxyapatite (HAp), chitosan (Chi) was in situ combined into HAp to fabricate a composite scaffold by a sublimation-assisted compression method. A highly porous film with sufficient mechanical strength was prepared and the bioactivity was investigated by examining the apatite formed on the scaffolds incubated in simulated body fluid. In addition, the cytotoxicity of the HAp/Chi composite was studied by evaluating the viability of murine fibroblasts (L-929 cells) exposed to diluted extracts of the composite films. The apatite layer was assessed using scanning electronic microscopy, inductively coupled plasma-optical emission spectrometry and weight measurement. Composite analysis showed that a layer of micro-sized, needle-like crystals was formed on the surface of the composite film. Additionally, the WST-8 assay after L-929 cells were exposed to diluted extracts of the composite indicated that the HAp/Chi scaffold has good in vitro cytocompatibility. The results indicated that HAp/Chi composites with porous structure are promising scaffolding materials for bone-patch engineering because their porous morphology can provide an environment conductive to attachment and growth of osteoblasts and osteogenic cells.

Biocompatibility of Nanoscale Hydroxyapatite-embedded Chitosan Films

Fangfang Sun,고광락,류수착,한동욱,이재범 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

In order to improve the bioactivity and mechanical properties of hydroxyapatite (HAp), chitosan (Chi) was in situ combined into HAp to fabricate a composite scaffold by a sublimation-assisted compression method. A highly porous film with sufficient mechanical strength was prepared and the bioactivity was investigated by examining the apatite formed on the scaffolds incubated in simulated body fluid. In addition, the cytotoxicity of the HAp/Chi composite was studied by evaluating the viability of murine fibroblasts (L-929 cells) exposed to diluted extracts of the composite films. The apatite layer was assessed using scanning electronic microscopy, inductively coupled plasma-optical emission spectrometry and weight measurement. Composite analysis showed that a layer of micro-sized, needle-like crystals was formed on the surface of the composite film. Additionally, the WST-8 assay after L-929 cells were exposed to diluted extracts of the composite indicated that the HAp/Chi scaffold has good in vitro cytocompatibility. The results indicated that HAp/Chi composites with porous structure are promising scaffolding materials for bone-patch engineering because their porous morphology can provide an environment conductive to attachment and growth of osteoblasts and osteogenic cells.

Changes in volatile organic compounds and diff erential expression of aroma-related genes during fl owering of Rosa rugosa ‘Shanxian’

Yaru Sun,Wenli Wang,Lan-yong Zhao,Chengshu Zheng,Fangfang Ma 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.5

Rosa rugosa ‘Shanxian’, a local variety of rose in Shandong Province, was studied for its aroma characteristics, includingchanges in aroma components and diff erential expression of aroma-related genes during fl owering. The volatiles emitted fromfl owers were collected by headspace solid-phase microextraction and analyzed by gas chromatography–mass spectrometry atthe budding stage, the early, half and full opening stages, and the withering stage. Sixty-six compounds were identifi ed, andthe full opening stage contained the highest level of every single aroma component compared with the other four stages. Themajor constituents of R. rugosa ‘Shanxian’ were alcohols, esters, ketones, aldehydes, phenols, and terpenes, with alcoholsbeing the most abundant. The aroma of R. rugosa ‘Shanxian’ was mainly characterized by rich fruit aromas, fl oral aromas, andsoft plant aromas. RrAAT , RrDXR , and RrDXS genes played a key role in monoterpene biosynthesis in R. rugosa ‘Shanxian’. The temporal and spatial expression of RrAAT , RrDXR , and RrDXS were measured at diff erent fl ower developmental stages. Among the three genes, the overall expression level of RrAAT was signifi cantly higher than that of RrDXR and RrDXS andwas associated with the accumulation of acetate esters in R. rugosa , which could be used as an important candidate gene forrose metabolism. Taken together, our results demonstrated that R. rugosa ‘Shanxian’ has better aromatic characteristics thanR. rugosa ‘Fenghua’. With a particularly prominent aroma that is strong and sweet, ‘Shanxian’ should be further investigatedas a valuable breeding material that could be used to enhance genetic diversity and develop new rose varieties.

Photoluminescence up-conversion of bioconjugated hybrids on CdTe and Au nanoparticles.

Kim, Seonghoon,Sun, Fangfang,Chen, Hongxia,Koh, Kwangnak,Kyhm, Kwangseuk,Lee, Jaebeom American Scientific Publishers 2009 Journal of nanoscience and nanotechnology Vol.9 No.12

<P>Semiconductor nanomaterials have attracted considerable attention in the design of high efficiency PL up-conversion in heterojunctions or nanostructures at extremely low continuous wave (cw)-excitation intensity. In this study, bioconjugated hybrids were constructed using CdTe and Au nanoparticles (NPs), where two-fold PL enhancement was observed in the solution state. These results are in accordance with theoretical predictions of the local-field effects associated with the combined influence of strong localization of the collective plasmon modes in metallic-semiconducting hybrids and multi-photon absorption into its localized plasmon modes. The feasibility of the nanohybrids as sensors was demonstrated by breaking the bioconjugation through thermal stress, which induced a rapid decrease in luminescence intensity. It is believed that the phenomena is applicable to high-compacted optoelectronic devices and sensing systems that take advantage of both quantum confinement effects and nonlinear optical properties.</P>

Hydroxyapatite coating on damaged tooth surfaces by immersion

Lim, Byoung-Ki,Sun, Fangfang,Ryu, Su-Chak,Koh, Kwangnak,Han, Dong-Wook,Lee, Jaebeom Institute of Physics Pub 2009 Biomedical materials Vol.4 No.2

<P>Hydroxyapatite (HAp) was coated on scratched areas of a human tooth and HAp disks by the immersion method in a HAp colloidal solution (⩽20 µm of average diameter dispersed in DI water). The surface morphologies of the scratched area after immersion for 1–3 months were investigated showing that the damaged surfaces were remarkably recovered. Then, the mechanical property and chemical stability of the HAp coating layers on both specimens were determined via the Vickers hardness test and concentration measurement of extracted Ca<SUP>2+</SUP> ions, respectively, after strong acidic treatment. The cellular behavior of mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) was also examined on the HAp layers regenerated on micro-scratched HAp disks for the purpose of their potential applications on maxillofacial bone conservation and reconstruction for prosthetic dentistry, and artificial disk preparation of a vertebral column. The notable loss of Ca<SUP>2+</SUP> ions under a highly acidic condition was not observed in the layers coated by HAp adsorption, indicating that the coating surface was well adhered with the original surfaces of the respective specimen. Moreover, the HAp adsorption did not adversely affect the adhesion, growth and proliferation of MC3T3-E1 cells on the coated HAp layers for up to 21 days. These results suggest that the HAp coating on the scratched areas of the tooth would be effectively applicable for the development of long-term prevention of micro-cleavage and tooth health supporters to reduce discoloration and further maxillofacial and orthopedic applications.</P>

Regeneration of a Micro-Scratched Tooth Enamel Layer by Nanoscale Hydroxyapatite Solution

류수착,Byoung-Ki Lim,Fangfang Sun,고광락,한동욱,이재범 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.4

Hydroxyapatite (HAp)-based materials have attracted considerable attention on account of their excellent stability and recrystallization. Nanoscale HAp powders with a mean particle size of 200 nm were used to regenerate the enamel layers of damaged teeth. An artificially scratched tooth was immersed in a nanoscale HAp powder suspension in d.i. water (HAp of 70 wt%) at 37 oC for a period of 1~3 months. SEM and AFM showed that the scratched surface was ultimately inlaid with HAp after three months and the roughness increased from 2.80 to 5.51. Moreover, the hardness of the neo-generated HAp layer on the crown was similar to that of the innate layer. Ca2+ and PO4 3- ions from the HAp powders dissolved in d.i. water were precipitated on the tooth to produce cemented pastes on the enamel surface due to its high recrystallizing characteristics, resulting in a hard neo-regenerated HAp layer on the enamel layer. This nanoscale HAp powder solution might be used to heal decayed teeth as well as to develop tooth whitening appliances.

Lateral Compression Behaviors of Thin-walled Equilateral Triangular Tubes

Hualin Fan,Wu Hong,Fangfang Sun,Ying Xu,Fengnian Jin 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.4

The paper deals with one important topic in impact engineering - the lateral compression behavior of thin-walled tubes. To study the lateral collapse modes and energy absorption behaviors of equilateral triangular tubes, quasi-static compression experiments were carried out. Crushing modes were revealed by the experiments. Three typical crushing stages characterize the lateral deformation plateaus of equilateral triangular tubes. In simulation, perfect tubes have symmetrical crushing modes. Strengths of the tubes were correctly predicted by the competition between yielding and buckling. Based on the observed crushing modes, plastic models were proposed for each stage to predict the lateral crushing behaviors theoretically. Equilateral triangular tubes have unified energy absorbing mechanisms, including five plastic hinges and one traveling plastic hinge. Plastic models have been constructed to predict the mean crushing forces and evaluate the energy absorption efficiency of the equilateral triangular tubes.

Bone Regeneration using Synthetic Hydroxyapatite Particulates, SB-1TM

류수착,Daehee Moon,Fangfang Sun,고광락,한동욱,황윤회,신상훈,이재범 한국생체재료학회 2011 생체재료학회지 Vol.15 No.2

This study was aimed at confirming the recovery of damaged bone tissue by using SB-1TM as a synthetic bone in clinical and in vivo studies. SB-1TM consists of 500~1400 μm synthetic hydroxyapatite (HAp) particles and has the same chemical composition as that of the inorganic part of human bones. Since SB-1TM is mainly composed of HAp and has excellent bioactivity, the graft integrated well with the surrounding host bone and promoted the induction of the new bone, thereby leading to bonding with the newly formed bone and recovery of the damaged bone tissue. Patients with damaged bones were surgically treated with SB-1TM, and bone recovery was monitored radiographically. In an in vivo study employing rabbits with tibial defects, SB-1TM showed superior bonding with the host bones and superior integration with the new bone as compared to those shown by allografts and bone grafts with low HAp content.

The Prediction Analysis of Autistic and Schizotypal Traits in Attentional Networks

Wanling Huang,Long Zhang,Yaoting Sun,Fangfang Chen,Kai Wang 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.5

Objective Empirical findings confirmed that autistic and schizotypal traits are associated with attentional function as well as include various dimensions. So far, no study has reported which dimension of these traits relates to attentional networks. This study aimed to find out whether there are associations between attentional networks and autistic traits; and between attentional networks and schizotypal traits.Methods A total of 449 volunteers was included in this study, and autism-spectrum quotient (AQ), schizotypal personality questionnaire (SPQ), and attention network test (ANT) were used to measure autistic traits and schizotypal traits. The three independent attentional networks, including alerting network, orienting network, and executive control network, were also measured.Results Autistic traits were associated with the orienting network, whereas schizotypal traits were associated with the orienting network and executive control network. Furthermore, attentional networks could be predicted by specific dimensions of autistic and schizotypal traits. AQ-attention switching [0.104 (-1.175– -0.025), p=0.041] and AQ-attention to detail [-0.097 (-0.798– -0.001), p=0.049] were significant predictors of orienting network and gender were significant predictor of executive network (Beta=0.107; 95% CI=-0.476–10.139; p=0.031). Whereas, schizotypal dimension “interpersonal” was a significant predictor of all three attentional networks [Alerting: 0.147 (-0.010–0.861), p=0.045; Orienting: 0.147 (0.018–0.733), p=0.040; Executive: 0.198 (0.215–1.309), p=0.006].Conclusion This study demonstrated that autistic and schizotypal traits were associated with attentional networks. The specific dimensions of autistic and schizotypal traits could predict attentional networks. Nevertheless, the attentional networks predicted with these two traits were different.