Poly(lactide-co-glycolide) nanofibrous scaffolds chemically coated with gold-nanoparticles as osteoinductive agents for osteogenesis

Lee, Donghyun,Heo, Dong Nyoung,Lee, Sang Jin,Heo, Min,Kim, Jeongho,Choi, Samjin,Park, Hun-Kuk,Park, Young Guk,Lim, Ho-Nam,Kwon, Il Keun Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.432 No.2

<P><B>Abstract</B></P> <P>Poly(lactide-co-glycolide) (PLGA) is a biocompatible and biodegradable polymer that has been widely used in devices for tissue engineering and drug delivery applications. Gold nanoparticles (GNPs) have also been used as biomaterials and have been found to have a positive effect on bone formation. In this study, we synthesized thiol end-capped PLGA (PLGA-SH) and used it for binding GNPs. This PLGA was processed into a sheet form via electrospinning. GNPs with an approximate size of 30nm were attached onto the PLGA-SH sheet surfaces (PLGA-GNPs). This membrane was characterized by thermogravimetric analysis, ultraviolet/visible spectrophotometry, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and confocal laser scanning microscopy. Characterization results show that the GNPs are well attached on the PLGA-SH sheet and it is possible to control the GNPs load. Additionally, in-vitro results showed that PLGA-GNPs have good biocompatibility. They were also found to enhance osteogenic differentiation of human adipose derived stem cells. From these results, we have determined that the PLGA-GNP fibers can be useful as materials for bone regeneration and can also potentially serve as drug carriers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We designed and prepared a novel PLGA nanofibrous sheet for binding GNPs using a simple process. </LI> <LI> The objective this study was to design a process for manufacturing PLGA-GNPs nanofibrous sheets which can be applied to biomaterials. </LI> <LI> The biocompatibility and osteoinductive effect of PLGA-GNPs were demonstrated through in vitro test using a human adipose derived stem cells. </LI> <LI> The developed scaffolds may be suitable as bone cell proliferation substrates for use in bone tissue engineering applications. </LI> </UL> </P>

In Situ Synthesis of Carbon Nanotubes/Graphene Nanoplateles Hybrid Materials with Excellent Mechanical Performance

Menglei Wang,Kejing Yu,Kun Qian 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.4

A two-step method for the preparation of hybrid materials consisting of multi-walled carbon nanotubes (MWCNTs) attached to graphene nanoplatelets (GNPs) was proposed. Firstly, poly (acryloyl chloride) was grafted in situ onto the surface of MWCNTs. Secondly, the obtained MWCNTs (MWCNTs-PACl) were reacted with acid-treated GNPs to form a nanotube–polymer– graphene hybrid. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA) were used to investigate the forming of the hybrid materials. FTIR results showed that MWCNTs/PACl and GNPs were successfully bridged by chemical bonds like O–C=O and C–O–C. Raman spectroscopy furthermore revealed that acryloyl chloride can be used to connect the MWCNTs and GNPs due to the defects of MWCNTs, and consequently the defects of the hybrid materials were limited. Meanwhile, TEM observation demonstrated the nanostructure clearly in which the MWCNTs with a polymer layer were attached successfully on the surface of GNPs. And TGA curves reflected that the content of MWCNTs and GNPs was about 46.5% in the hybrid materials. In addition, the tensile tests results showed that MWCNTs/GNPs hybrid materials can improve the mechanical performance of epoxy composites in higher degree, compared with MWCNTs or GNPs particles alone.

Flexible GnPs/EPDM with Excellent Thermal Conductivity and Electromagnetic Interference Shielding Properties

Shaowei Lu,Yaoyao Bai,Jijie Wang,Dandan Chen,Keming Ma,Qingshi Meng,Xinmin Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.6

As the portable device hardware has been increasing at a noticeable rate, ultrathin flexible materials with the combination of high thermal conductivity and excellent electromagnetic interference (EMI) shielding performance are urgently needed. Here, we fabricated ethylene propylene diene monomer rubber with different loading graphene nanoplatelets (GnPs/EPDM) by a cost-efficient approach, which combines mixing, ultrasonication and compression. Further investigation demonstrates that the 8 wt.% GnPs/EPDM with only 0.3 mm in thickness shows excellent electrical conductivity (28.3 S/m), thermal conductivity (0.79 W/mK) and good mechanical properties. Besides, the 8 wt.% GnPs/EPDM exhibits an EMI shielding effectiveness (SE) up to 33 dB in the X-band (8.2–12.4 GHz) and 35 dB in the Ku-band (12.4–18 GHz), superior to most of the reported rubber matrix. Additionally, the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion (under 5% NaCl environment) for a week. Our flexible EMI shielding material will benefit the fast-growing next-generation commercial portable flexible electrons.

Synthesis of Synchrotron Radiation-induced Gold Nanoparticles as Radiosensitizer in Radiotherapy

Se An Oh,Jae Won Park,Seong Hoon Kim,Sung Kyu Kim,Ji Woon Yea,Su Yong Lee,Hyon Chol Kang 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.11

This study investigated the feasibility of synthesizing GNPs using synchrotron radiation X-ray for use as a radiosensitizer in radiotherapy, and examined the morphology of the GNPs. Different concentration ratios of 4-mM gold precursor aqueous solution and 4-mM NaHCO3 were mixed. This gold precursor aqueous solution was continuously irradiated with synchrotron radiation in the 4B X-ray microdiffraction beamline of Pohang Light Source (PLS)-II in Korea. The SEM, EDS, TEM, and XRD spectra of the GNPs synthesized using the synchrotron radiation were investigated. The GNPs synthesized using the synchrotron radiation were nanocrystals predominantly in the (111) direction of the face-centered cubic structure. We found that the shape of the gold nanoparticles was icosahedron at the molar concentrations of 0.25 mM:0.25 mM and 0.5 mM:0.5 mM mixed with 4 mM HAuCl43H2O and 4 mM NaHCO3 solutions.

DETERMINATION OF AMINOGLYCOSIDE ANTIBIOTICS BY A COLORIMETRIC METHOD BASED ON THE AGGREGATION OF GOLD NANOPARTICLES

RUIYONG WANG,SHUMIN FAN,RUIQIANG WANG,RUI WANG,HUANJING DOU,LVJING WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.4

A sensitive and selective colorimetric biosensor for determination of gentamicin, amikacin and tobramycin was proposed with the unmodified gold nanoparticles (GNPs) as the sensing element. Gentamicin, amikacin and tobramycin can rapidly induce the aggregation of gold nanoparticles and is accompanied by a color change from red to blue. The concentration of gentamicin, amikacin and tobramycin can be determined by using UV-Vis spectrometer. The experimental parameters were optimized with regard to pH, incubation time and the concentration of the GNPs. Under optimal experimental conditions, the linear range of the colorimetric sensor for gentamicin/amikacin/tobramycin were 2.67–33.93 ng mL-1, 13.33–66.67 ng mL-1 and 20–180 ng mL-1, respectively. The corresponding limit of detection (3σ) was 0.354 ng mL-1, 0.999 ng mL-1 and 0.579 ng mL-1, respectively. This assay was simple and used to detect aminoglycoside antibiotics in milk and medicine products.

In situ green synthesis of Au/Ag nanostructures on a metal-organic framework surface for photocatalytic reduction of p-nitrophenol

Karanveer Singh,Deepak Kukkar,Ravinder Singh,Preeti Kukkar,Nardev Bajaj,Jagpreet Singh,Mohit Rawat,Akshay Kumar,Ki-Hyun Kim 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

In this manuscript, we report the insitu growth of gold nanoparticles (GNPs) and silver nanoparticles(SNPs) over Ce/Tb-doped Y-benzene tricaroboxylate metal organic frameworks (MOF-76). Thephotocatalytic potential of these nanocomposites (NCs) was then assessed for the photocatalyticreduction of p-nitrophenol (p-NP) in aqueous medium. The NCs had large surface area to favorablyshowcase the efficient absorption of light energy. Correspondingly, it facilitated the electron transferbetween the valance and conduction bands to promote the reductive removal of p-NP. Among the testedcatalysts, GNPs@MOF-76 (Ce) (MOF-76(1a)) (dosage: 10 ml of 5 mg.ml 1) recorded the maximumcatalytic efficiency (96.3%) with an apparent rate constant (K0app: 0.33 min 1). Further, MOF-76 (1a) NCsexhibited good recyclability (e.g., a catalytic efficiency of 77.45% over 3 cycles). Moreover, the proposedNCs exhibited superior performance over commercial photocatalysts (e.g., p25 TiO2 nanopowder)towards p-NP reduction. As such, the results of this experimental study successfully demonstrated thesuperiority of the MOF immobilized nanoparticles (NPs) as an efficient platform for the removal ofindustrial grade pollutants.

Dry Sliding Wear Behavior of (MWCNT + GNPs) Reinforced AZ91 Magnesium Matrix Hybrid Composites

Muhammet Emre Turan,Huseyin Zengin,Yavuz Sun 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.4

This study aims to improve tribological performance of magnesium alloy with the addition of carbonaceous (C-based) reinforcements. Synergetic effects of MWCNT and GNPs on wear performance of AZ91 magnesium alloy was evaluated withthis report. AZ91-0.3 wt% MWCNT and AZ91-0.15 wt% MWCNT-0.15 wt% GNPs hybrid composites were synthesizedusing hot pressing via semi powder metallurgy. Microstructures were examined by scanning electron microscope and x-raydiffraction test devices then hardness and wear tests were performed for all samples. Results clearly show that hardnessand wear behaviors of AZ91 magnesium alloy were improved significantly with the addition of reinforcements. Uniformdistribution of carbon atoms was achieved for both of two samples. AZ91-0.15 wt% MWCNT-0.15 wt% GNPs compositeshowed best wear performance among the specimens.

Synthesis of arbutin–gold nanoparticle complexes and their enhanced performance for whitening

Jin Ju Park,Su Jung Hwang,Yu Sun Kang,Jisung Jung,Suryeon Park,Jee Eun Hong,Yohan Park,Hyo-Jong Lee 대한약학회 2019 Archives of Pharmacal Research Vol.42 No.11

Arbutin, a natural polyphenol, possessesnumerous biological activities including whitening, antioxidant,anti-cancer, anti-inflammatory activities, as wellas strong reducing power, making it an ideal bioactiveingredient for preparing gold nanoparticles (GNPs). Previously,we developed a novel green, mild syntheticmethod for GNPs using glycosides such as arbutin asreducing agents and stabilizers. Herein, we optimized thesynthetic method for glycoside–GNPs using arbutin,methyl b-D-glucoside, and phenyl b-D-glucoside and validatedtheir whitening efficacy in vitro and in vivo. Theresulting glycoside–GNPs were predominantly mono-dispersedand spherical (10.30–17.13 nm diameter). Comparedwith arbutin itself, arbutin–GNP complexes (GNPA1and GNP-P2) displayed enhanced whitening capabilities. Furthermore, GNP-P2 exhibited enhanced anti-inflammatoryactivity and lacked the toxicity associated witharbutin. Bioactive glycoside–GNP complexes may opennew directions for cosmeceuticals, and GNP-P2 may serveas a useful whitening ingredient in future cosmeceuticalapplications.

분자영상용 방사성 금 나노입자 합성

손민주,노종국,이주상,장범수,박상현 한국방사선산업학회 2012 방사선산업학회지 Vol.6 No.2

Gold nanoparticles (GNPs) have led to the development of a new field in the diagnosisand treatment of diseases such as cancer. An efficient synthesis of gold nanoparticles within therange of 8~57 nm was established by γ-ray irradiation. The good point of a radiation-basedmethod is the production of gold nanoparticles with a higher concentration and narrower sizedistribution compared with conventional methods. The size of gold nanoparticles was controlledusing two methods. : (i) varying the γ-ray irradiation dose of 10 to 25 kGy and (ii) varying the concentrationof HAuCl4 solution from 4 to 40 mM. In addition, the GNPs were radiolabeled using[125I]NaI in a simple and fast manner with high yields. The produced gold nanoparticles were characterizedusing a transmission electron microscopy (TEM), a UV-visible spectrophotometer, anda radio-TLC imaging scanner. From these results, these radiolabeled GNPs can be applicable fora radioisotope tag of biomolecules.

Recent advances on the enhanced thermal conductivity of graphene nanoplatelets composites: a short review

Danial Wan Hazman,Abdul Majid Zaiton 한국탄소학회 2022 Carbon Letters Vol.32 No.6

Graphene nanoplatelets (GNPs) have garnered significant attention in the field of thermal management materials due to their unique morphology and remarkable thermal conductive properties. Their impressive thermal properties make them an interesting choice of nanofillers with which to produce multifunctional composite materials and a host of other applications whilst their structural and thermal properties significantly improve their target materials or composites. Therefore, this present study reviewed recent advances in the use of GNPs as nanofillers to enhance the thermal conductivity of various materials or composites. The improved thermal conductivity that GNPs impart in composites is also comprehensively compared and discussed. Therefore, this review may reveal hitherto unknown opportunities and pave the way for the production of materials with enhanced thermal applications including electronics, aerospace devices, batteries, and structural reinforcement.