• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.867-868
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• 2009

• 한국분말재료학회지
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• 제27권2호
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• pp.154-163
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• 2020

Fluorescent nanoparticles are characterized by their unique properties such as luminescence, optical transparency, and sensitivity to various chemical environments. For example, semiconductor nanocrystals (quantum dots), which are nanophosphors doped with transition metal or rare earth ions, can be classified as fluorescent nanoparticles. Tuning their optical and physico-chemical properties can be carried out by considering and taking advantage of nanoscale effects. For instance, quantum confinement causes a much higher fluorescence with nanoparticles than with their bulk counterparts. Recently, various types of fluorescent nanoparticles have been synthesized to extend their applications to other fields. In this study, State-of-the-art fluorescent nanoparticles are reviewed with emphasis on their analytical and anti-counterfeiting applications and synthesis processes. Moreover, the fundamental principles behind the exceptional properties of fluorescent nanoparticles are discussed.

• 한국가시화정보학회지
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• 제9권2호
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• pp.16-20
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• 2011

This paper presents a fabrication method of microcapsules encapsulating fluorescent nanoparticles sensitive to an organic liquid, which is potentially applicable to the encapsulation of protein, cell and drug. It uses the supra-molecular self-assembly of a block copolymer at the interface of the stable and controllable droplets of water suspended with fluorescent nanoparticles and the polymer solved organic. The size and uniformity of the microcapsules were examined for the various polymer concentrations by using SEM image analysis. The maximum standard deviation of the produced microcapsules of less than 3.5% was obtained from the microcapsules produced from the same conditions. The inclusion of fluorescent nanoparticles was visualized in the fluorescence microscope and by using TEM image. It is shown that this fabrication method can provide the uniform size microcapsules with a higher inclusion.

• 대한화학회지
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• 제55권1호
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• pp.132-135
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• 2011

• 정보저장시스템학회논문집
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• 제8권1호
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• pp.1-5
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• 2012

We present a method for preparing a quantum dot fluorescent monolayer film on a glass substrate. Since nanoparticles aggregate easily, it is difficult to prepare a nanoparticle monolayer film. We have used a covalent bond, the peptide bond, to fix quantum dots on the glass substrate. The surface of the quantum dot was functionalized with carboxyl groups, and the glass substrate was also functionalized with amino groups using a silane coupling agent. The carboxyl group can be strongly coupled to the amino group. We were able to successfully prepare a monolayer film of CdSe quantum dots on the glass substrate.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.2906-2910
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• 2011

A fluorescent nucleoside analogue, $^AC$, featuring two non-complementary nucleobases linked through an ethynyl group, was synthesized. The extended ${\pi}$-conjugation imparts $^AC$ with red-shifted absorbance (relative to adenine and cytosine) and pale-blue fluorescence. It spontaneously forms nanoparticles, which exhibit considerably enhanced fluorescence, without the help of any additional stabilizing agent. The DMSO/water ratio was an important factor influencing the construction of the NPs. X-ray crystallography confirmed the structure of $^AC$; dynamic light scattering and scanning electron microscopy confirmed the existence of the nanoparticles.

• 한국가시화정보학회지
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• 제3권1호
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• pp.3-19
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• 2005

Novel optical techniques are presented for three-dimensional tracking of nanoparticles; Optical Serial Sectioning Microscopy (OSSM) and Ratiometric Total Internal Reflection Fluorescent Microscopy (R-TIRFM). OSSM measures optically diffracted particle images, the so-called Point Spread Function (PSF), and dotermines the defocusing or line-of-sight location of the imaged particle measured from the focal plane. The line-of-sight Brownian motion detection using the OSSM technique is proposed in lieu of the more cumbersome two-dimensional Brownian motion tracking on the imaging plane as a potentially more effective tool to nonintrusively map the temperature fields for nanoparticle suspension fluids. On the other hand, R-TIRFM is presented to experimentally examine the classic theory on the near-wall hindered Brownian diffusive motion. An evanescent wave field from the total internal reflection of a 488-nm bandwidth of an argon-ion laser is used to provide a thin illumination field of an order of a few hundred nanometers from the wall. The experimental results show good agreement with the lateral hindrance theory, but show discrepancies from the normal hindrance theory. It is conjectured that the discrepancies can be attributed to the additional hindering effects, including electrostatic and electro-osmotic interactions between the negatively charged tracer particles and the glass surface.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2905-2908
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• 2009

Immuno-sensing for high accurate and selective sensing was performed by fluorescence spectroscopy and surface plasmon resonance (SPR), respectively. Engineered assembly of two fluorescent quantum dots (QDs) with bovine serum albumin (BSA) and anti-BSA was fabricated in PBS buffer for fluorescence analysis of fluorescence resonance energy transfer (FRET). Furthermore, the same bio-moieties were immobilized on Au plates for SPR analysis. Naturally-driven binding affinity of immuno-moieties induced FRET and plasmon resonance angle shift in the nanoscale sensing system. Interestingly, the sensing ranges were uniquely different in two systems: e.g., SPR spectroscopy was suitable for highly accurate analysis to measure in the range of 10$^{-15{\sim}-10$ng/mL while the QD fluorescent sensing system was relatively lower sensing ranges in 10$^{-10{\sim}-6$ng/mL. However, the QD sensing system was larger than the SPR sensing system in terms of sensing capacity per one specimen. It is, therefore, suggested that a mutual assistance of FRET and SPR combined sensing system would be a potentially promising candidate for high accuracy and reliable in situ sensing system of immune-related diseases.

• 한국산학기술학회논문지
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• 제20권5호
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• pp.1-6
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• 2019

유기 염료가 도핑 된 실리카 나노입자는 바이오 라벨링, 바이오 이미징 및 바이오 센싱에 사용되고 있는 유망한 나노소재이다. 일반적으로 형광 실리카 나노입자는 수정된 스토버 방법($St{\ddot{o}}ber$ Method)으로 합성된다. 본 연구에서는 다양한 크기를 갖는 염료가 첨가되지 않은 형광 실리카 나노입자를 수정된 스토버 합성법인 졸겔 공정으로 합성하였다. 졸겔 공정 중에 기능성 물질인 APTES를 첨가제로 첨가하였다. 졸겔 공정으로 합성된 실리카 나노입자는 $400^{\circ}C$에서 2시간 동안 하소되었다. 합성된 실리카 나노입자의 표면형상과 크기를 전계방출 주사전자현미경으로 조사하였고, 합성된 실리카 나노입자의 형광 특성은 파장 365 nm의 자외선 램프를 조사하여 확인하였다. 또한 합성된 실리카 나노입자의 광발광 (PL) 특성을 형광 분석 형광법으로 조사하였다. 그 결과 합성된 실리카 나노입자는 입자의 크기와 무관하게 모두 청색 형광 특성을 갖는 것으로 확인되었다. 특히, 실리카 나노입자의 크기가 증가할수록 PL 강도는 감소하였다. 염료가 첨가되지 않은 실리카 나노입자의 청색 형광 특성은 APTES 층의 $NH_2$ 기능기와 실리카 매트릭스 뼈대 내부의 산소관련 결함과의 결합에 기인하는 것으로 추정된다.

• 센서학회지
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• 제30권2호
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• pp.119-124
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• 2021

Isolation and separation of biological nanoparticles, such as cells and extracellular vesicles, are important techniques for their characterization. Dielectrophoresis (DEP) based on microfluidic chips is an effective method to isolate and separate the nanoparticles. However, the electrodes of the DEP chips are electrolyzed by the electrical signals applied to the nanoparticles. Thus, the isolation/separation efficiency of the nanoparticles is reduced considerably. Through this study, we developed a microfluidic DEP chip for reliable isolation/ separation of nanoparticles and developed a passivation technique for the protection of the DEP chip electrodes. The electrode passivation process was designed using a hydrogel and the stability of the hydrogel passivation layer was verified. The fabricated DEP chip and the proposed passivation technique were used for the collection and dispersion of the fluorescent polystyrene nanoparticles. The proposed chip and the technique for isolation and separation of nanoparticles can be leveraged in various bioelectronic applications.