One-Pot Preparation of Antibacterial Electrospun Polycaprolactone Membrane Embedded with Gamma Irradiation-Induced Silver Nanoparticles

Chien Minh Tran,Ngoc Thi‑Thanh Nguyen,Minh Hieu Ho,Vinh Khanh Doan,Khanh Loan Ly,Nhi Ngoc‑Thao Dang,Nam Minh‑Phuong Tran,Hoai Thi‑Thu Nguyen,Long Phuoc Truong,Thai Minh Do,Quyen Ngoc Tran,Hien Quoc Ng 한국섬유공학회 2023 Fibers and polymers Vol.24 No.1

In this study, we proposed a straightforward electrospun polycaprolactone (PCL) loaded with silver nanoparticles (SNPs)membrane fabrication process, in which SNPs were directly synthesized from silver nitrate (AgNO3) in PCL–acetone mixtureby gamma irradiation. The insolubility of AgNO3in PCL solution was solved using an auxiliary dimethyl sulfoxide solvent. As a physical approach, gamma rays readily converted silver ions into SNPs without the addition of harmful reductionagents, which reduced the cytotoxicity of the synthesized material. By avoiding some processes such as purification, solventremoval, or redispersion of SNPs, this method was more time-saving compared to other related studies. SNPs formation wasconfirmed by both UV–Visible spectrum (UV–Vis) and X-ray diffraction analysis. Scanning electron microscopy (SEM)revealed that the addition of SNPs significantly reduced the fiber diameter of PCL–Ag membranes compared to that of rawPCL. Uniform spherical-shaped SNPs incorporated in PCL fibers were observed under transmission electron microscopy(TEM). The tensile test showed that the electrospun PCL–Ag membranes exhibited good mechanical characteristics. Moistureeasily penetrated the porous microstructure of PCL–Ag, facilitating wound humidity regulation. Inductively coupledplasma-mass spectroscopy (ICP-MS) was employed to study the release profiles of SNPs at different time intervals. Overall,the PCL–Ag 500 ppm sample exerted excellent antibacterial activity against Pseudomonas aeruginosa and Staphylococcusaureus strains and low in vitro cytotoxicity.

Bioadhesive PAA-PEG-PAA Triblock Copolymer Hydrogels for Drug Delivery in Oral Cavity

Minh Khanh Nguyen,이두성 한국고분자학회 2010 Macromolecular Research Vol.18 No.3

A series of poly(amidoamine)-poly(ethylene glycol)-poly(amidoamine) (PAA-PEG-PAA) triblock copolymers were designed and prepared to examine the factors affecting their sol-gel transition behavior. The physiochemical properties of the triblock copolymers were characterized by 1H NMR spectroscopy and gel permeation chromatography. The PAA-PEG-PAA copolymers underwent sol-gel transitions in solution (10-15 wt%) in response to changes in both the pH and temperature. The sol-gel transition phase behavior was controlled by adjusting the molecular weights of the PEG and PAA blocks and changing the PAA-PEG-PAA concentration. These copolymers demonstrated stronger bioadhesive properties than chitosan and poly(acrylic acid) in an aqueous solution. The in vitro release of flubiprofen was controllable using these copolymer hydrogels.

Oligo(amidoamine)s hydrogels with tunable gel properties

Nguyen, Minh Khanh,Lee, Doo Sung Royal Society of Chemistry 2010 Chemical communications Vol.46 No.20

<P>A series of oligo(amidoamine)s (OAAs) that can be reversibly switched between sol and gel phases upon changes in pH and temperature have been synthesized and characterized. Their viscoelastic properties were significantly increased upon increasing the number of methylene groups, implying that viscoelasticity could clearly be tuned at the molecular level.</P> <P>Graphic Abstract</P><P>OAA gelators in aqueous solutions show a pH- and temperature-dependent sol-to-gel transition that allows them to be easily injected into the body. The viscoelasticity of the gels is easily tuned at the molecular level by modulating the gel structure. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c002169e'> </P>

Injectable Biodegradable Hydrogels

Nguyen, Minh Khanh,Lee, Doo Sung WILEY-VCH Verlag 2010 Macromolecular bioscience Vol.10 No.6

<P>Injectable biodegradable copolymer hydrogels, which exhibit a sol gel phase transition in response to external stimuli, such as temperature changes or both pH and temperature (pH/temperature) alterations, have found a number of uses in biomedical and pharmaceutical applications, such as drug delivery, cell growth, and tissue engineering. These hydrogels can be used in simple pharmaceutical formulations that can be prepared by mixing the hydrogel with drugs, proteins, or cells. Such formulations are administered in a straightforward manner, through site-specific control of release behavior, and the hydrogels are compatible with biological systems. This review will provide a summary of recent progress in biodegradable temperature-sensitive polymers including polyesters, polyphosphazenes, polypeptides, and chitosan, and pH/temperature-sensitive polymers such as sulfamethazine-, poly(beta-amino ester)-, poly(amino urethane)-, and poly(amidoamine)-based polymers. The advantages of pH/temperature-sensitive polymers over simple temperature-sensitive polymers are also discussed. A perspective on the future of injectable biodegradable hydrogels is offered.</P>

Biodegradable oligo(amidoamine/β-amino ester) hydrogels for controlled insulin delivery

Nguyen, Minh Khanh,Huynh, Cong Truc,Gao, Guang Hui,Kim, Ji Hyun,Huynh, Dai Phu,Chae, Su Young,Lee, Kang Choon,Lee, Doo Sung The Royal Society of Chemistry 2011 Soft matter Vol.7 No.6

<P>An injectable biodegradable hydrogel system based on oligo(amidoamine/β-amino ester) (OAAAE) was designed and synthesized for controlled release of insulin under the physiological conditions. OAAAE was prepared in one step <I>via</I> the Michael-addition oligomerization of the secondary aminegroups of 4,4-trimethylene dipiperidine (TMDP) with the vinyl groups of 1,8-octylene diacrylamide (ODA) and 1,6-hexane diol diacrylate (HDA). The formed oligomer was characterized by <SUP>1</SUP>H NMR and gel permeation chromatography (GPC). OAAAE in aqueous solution (20 wt%) underwent a gel–sol transition in the pH range of 6.8–7.4. A complex hydrogel was formed when mixinginsulin with the oligomer solution followed by increasing pH and temperature. Degradation of the hydrogel, influence of insulin on gel phase and gel strength, <I>in vitro</I> cytotoxicity of OAAAE, <I>in vitro</I> and <I>in vivo</I> release of insulin from the complex hydrogel were investigated. Furthermore, the <I>in vivo</I> release profile of insulin from the complex hydrogel was compared with that from the neutral hydrogel.</P> <P>Graphic Abstract</P><P>Controlled protein release using injectable and biodegradable oligomer hydrogel. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0sm01285h'> </P>

Influence of Red Y2O3:Eu3+ Phosphor Concentration to the Multi-Chip White LEDs Color Rendering Ability

Nguyen Huu Khanh Nhan,Tran Hoang Quang Minh,Nguyen Doan Quoc Anh 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.4

In this paper, a novel solution and application of the red Y2O3:Eu3+ dopant phosphor for enhancing color rendering index to more 86 for multi-chip white LED lamps (MCW-LEDs), which have correlated color temperature (CCT) of 7700 K, 6600 K, 5600 K, are presented. Then the effect of the concentration of Y2O3:Eu3+ phosphor on the color rendering index (CRI) is simulated, analyzed and demonstrated. After that the lumen output of MCW-LEDs depended on concentration Y2O3:Eu3+ phosphor is discovered. The lumen output has a decrease tendency at large weight range due to the enhancement extinction coefficient, according to Mie-scattering theory. Simulation results provided important conclusions for selecting and developing the phosphor materials in MCW-LEDs manufacturing.

Bi-layers Red-emitting Sr2Si5N8:Eu2+ Phosphor and Yellow-emitting YAG:Ce Phosphor: A New Approach for Improving the Color Rendering Index of the Remote Phosphor Packaging WLEDs

Nguyen Huu Khanh Nhan,Tran Hoang Quang Minh,Tan N. Nguyen,Miroslav Voznak 한국광학회 2017 Current Optics and Photonics Vol.1 No.6

Due to optimal advances such as chromatic performance, durability, low power consumption, highefficiency, long-lifetime, and excellent environmental friendliness, white LEDs (WLEDs) are widely usedin vehicle front lighting, backlighting, decorative lighting, street lighting, and even general lighting. In thispaper, the remote packaging WLEDs (RP-WLEDs) with bi-layer red-emitting Sr2Si5N8: Eu2+ and yellowemittingYAG:Ce phosphor was proposed and investigated. The simulation results based on the MATLABsoftware and the commercial software Light Tools indicated that the color rendering index (CRI) of bi-layerphosphor RP-WLEDs had a significant increase. The CRI had a considerable increase from 72 to 94. Inconclusion, the results showed that bi-layer red-emitting Sr2Si5N8:Eu2+ and yellow-emitting YAG:Cephosphor could be a prospective approach for manufacturing RP-WLEDs with enhanced optical properties.

Removal of nutrients and organic pollutants from domestic wastewater treatment by sponge-based moving bed biofilm reactor

Huynh Tan Nhut,Nguyen Tri Quang Hung,Tran Cong Sac,Nguyen Huynh Khanh Bang,Tran Quang Tri,Nguyen Trung Hiep,Nguyen Minh Ky 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.5

This study evaluates the efficiency of domestic wastewater treatment via Sponge-Based Moving Bed Biofilm Reactor (S-MBBR). The laboratory-based treatment plan uses polyurethane sponge with a specific surface area was 260 ㎡/㎥ as a carrier. The treatment plan operated under four different organic load rate: OLR1 = 0.4 ㎏ BOD/㎥.day; OLR2 = 0.6 ㎏ BOD/㎥.day; OLR3 = 0.8 ㎏ BOD/㎥.day; and OLR4 = 1.0 ㎏ BOD/㎥.day. During 80 d of the experiment, the highest treatment efficiency was at the organic load rate of 0.4 ㎏ BOD/㎥.day, with COD, SS, TN and TP were found to be 85.0 ± 12.9%, 85.7 ± 5.3%, 68.9 ± 1.7%, and 40.3 ± 0.2%, respectively. In which, the influent SS concentration were from 117.3 to 126.0 ㎎/L, the effluent concentration were in ranged 18.0 to 34.22 ㎎/L, respectively. The values of influent and effluent COD were 298.8 ± 12.88 and 44.8 ± 3.78 ㎎/L in turn. The OLR1 influent TN, TP concentrations were respectively 47.9 ± 2.11 and 3.6 ± 0.15 ㎎/L; the effluent TN, TP concentration were 14.9 ± 0.18 and 2.2 ± 0.06 ㎎/L, respectively. The study suggests that the effluent is within the allowable limits of National technical regulation on domestic wastewater (Column B1), indicating the applicability of S-MBBR for the domestic wastewater treatment plant.

Impacts of Corporate Social Responsibility and Authenticity on Brand Loyalty: Evidence from the Chain Coffee Shop Industry in Vietnam

MAI, Thi Cam Tu,NGUYEN, Hong Son,PHAN, Nguyen Ngoc Diem,LE, Minh Hang,LUU, Phuong Khanh,NGUYEN, Thi Thu Thao,NGUYEN, Thi Thu Trang Korea Distribution Science Association 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.6

This study examines the impact of CSR and its authenticity on customer loyalty through the brand image in the chain coffee shop industry. Using qualitative and quantitative methods, 601 survey questionnaires were distributed, of which 491 were analyzed. The results show that CSR has a positive impact on brand image and customer loyalty. In addition, authenticity does not moderate the impact of CSR on brand image and loyalty, as it is difficult for customers to verify the authenticity of CSR action programs. This study emphasizes the importance of CSR action programs and authenticity for businesses to sustainably enhance their distinctive brand image and customer loyalty. Therefore, for sustainable development in the future, managers of coffee shop chains need to focus on the following issues. First, the most important thing is the right awareness of businesses regarding CSR and CSR authenticity. Third, businesses should strengthen the transparency of CSR action programs in various media so that consumers can easily verify authenticity, to increase brand image and improve customer loyalty.

Enhancement Spatial Color Uniformity of White Light LED Lamps by Adding Silicon Dioxides in Phosphor Layer

Nguyen Doan Quoc Anh,Tran Hoang Quang Minh,Nguyen Huu,Khanh Nhan 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.5

Recently, high-power light-emitting diodes (LEDs) have attracted great attention on the study and made remarkable progress. In this paper, method for enhancing uniform white light of a multi-chip white light LED by adding silicon dioxides in the phosphor layer is presented. Firstly, theory of study by using Mie theory and Monte Carlo ray-tracing is proposed. And then simulation and experimental results by using package LightTools software are performed. The experimental results and theory have the same direction: 1) the angular color temperature in narrow angles is much higher than that in wider angles for the non-SiO2 case and 2) in significantly reducing CCT deviation of a multi-chip white light LED by adding silicon dioxides in the phosphor layer.