Imaging depths of near-infrared quantum dots in first and second optical windows.

Won, Nayoun,Jeong, Sanghwa,Kim, Kangwook,Kwag, Jungheon,Park, Joonhyuck,Kim, Sang Geol,Kim, Sungjee MIT Press 2012 Molecular imaging Vol.11 No.4

<P>Potential advantages of quantum dot (QD) imaging in the second optical window (SOW) at 1,000 to 1,400 nm over the first optical window (FOW) at 700 to 900 nm have attracted much interest. QDs that emit at 800 nm (800QDs) and QDs that emit at 1,300 nm (1,300QDs) are used to investigate the imaging depths at the FOW and SOW. QD images in biologic tissues are processed binarized via global thresholding method, and the imaging depths are determined using the criteria of contrast to noise ratio and relative apparent size. Owing to the reduced scattering in the SOW, imaging depth in skin can be extended by approximately three times for 1,300QD/SOW over 800QD/FOW. In liver, excitation of 1,300QD/SOW can be shifted to longer wavelengths; thus, the imaging depth can be extended by 1.4 times. Effects of quantum yield (QY), concentration, incidence angle, polarization, and fluence rate F on imaging depth are comprehensively studied. Under F approved by the Food and Drug Administration, 1,300QDs with 50% QY can reach imaging depths of 29.7 mm in liver and 17.5 mm in skin. A time-gated excitation using 1,000 times higher F pulses can obtain the imaging depth of ? 5 cm. To validate our estimates, in vivo whole-body imaging experiments are performed using small-animal models.</P>

Metal ion-induced dual fluorescent change for aza-crown ether acridinedione-functionalized gold nanorods and quantum dots

Velu, Ranganathan,Won, Nayoun,Kwag, Jungheon,Jung, Sungwook,Hur, Jaehyun,Kim, Sungjee,Park, Nokyoung The Royal Society of Chemistry 2012 New journal of chemistry Vol.36 No.9

<P>Aza-crown ether acridinedione-functionalized quantum dots (ACEADD-QDs) and aza-crown ether acridinedione-functionalized gold nanorods (ACEADD-GNRs) have been developed as a pair for a fluorescent chemosensor detecting metal ions. The ACEADD-QDs have dual emissions at a visible wavelength of ∼430 nm from the acridinedione dye moiety and at a near-infrared (NIR) wavelength of ∼775 nm from the CdTeSe QDs. In the presence of Ca<SUP>2+</SUP> or Mg<SUP>2+</SUP> ions, the ACEADD-QD and ACEADD-GNR pair can form a sandwich complex mediated by the metal ion. The ACEADD-QD and ACEADD-GNR complex pair shows visible fluorescence enhancement from the acridinedione dye and concurrent fluorescence quenching from the NIR QD. The aza-crown ether complex results in the suppression of photoinduced electron transfer from the aza-crown ether to the acridinedione dye moiety. At the same time, the QD fluorescence can be effectively quenched by the nanometal surface energy transfer from the QD to the GNR. This ACEADD-QD and ACEADD-GNR pair can effectively transduce the selective binding event of crown ethers with metal ions into the simultaneous modulation of the enhancement in dye fluorescence and the quenching of QD emission, which can open a new strategy for ratiometric sensors that are selective and robust against the environment conditions.</P> <P>Graphic Abstract</P><P>A pair of aza-crown ether acridinedione-functionalized quantum dots and gold nanorods has been developed for a selective metal ion sensor <I>via</I> ratiometric fluorescence modulations. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2nj40444c'> </P>

One-Pot Fabrication of High-Quality InP/ZnS (Core/Shell) Quantum Dots and Their Application to Cellular Imaging

Hussain, Sahid,Won, Nayoun,Nam, Jutaek,Bang, Jiwon,Chung, Hyokyun,Kim, Sungjee WILEY-VCH Verlag 2009 Chemphyschem Vol.10 No.9

<P>True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure). <img src='wiley_img/14394235-2009-10-9-10-CPHC200900159-content.gif' alt='wiley_img/14394235-2009-10-9-10-CPHC200900159-content'> </P> <B>Graphic Abstract</B> <P>True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure). <img src='wiley_img/14394235-2009-10-9-10-CPHC200900159-content.gif' alt='wiley_img/14394235-2009-10-9-10-CPHC200900159-content'> </P>

pH-Induced Aggregation of Gold Nanoparticles for Photothermal Cancer Therapy

Nam, Jutaek,Won, Nayoun,Jin, Ho,Chung, Hyokyun,Kim, Sungjee American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.38

<P>We report a 'smart' gold nanoparticle that is designed to aggregate in mild acidic intracellular environments by its hydrolysis-susceptible citraconic amide surface. With a relatively small size of 10 nm, the 'smart' gold nanoparticles can be efficiently internalized into cancerous cells. Triggered by pH change, the nanoparticle surfaces are engineered to have both positive and negative charges. Electrostatic attractions between the nanoparticles can rapidly form aggregates inside the cells, and the aggregates accumulate as the exocytosis is blocked by the increased size. Endocytosis of gold nanoparticles and the aggregation are monitored real-time by dark field optical microscopy. The pH-induced formation of aggregates shifts the absorption to far-red and near-infrared. The absorption shift to longer wavelength is used for photothermal cancer therapy as it guarantees maximal tissue penetration for potential therapeutic applications. The gold nanoparticles show selective and efficient destruction of cancerous cells with an intensity threshold of 5 W/cm(2) to induce the thermal destruction. In the intensity range 5-13 W/cm(2), the circular area of damaged cells increases linearly with the irradiation power density. This shows a new proof-of-concept for photothermal cancer therapy that exploits collective plasmon modes of metal nanoparticles.</P>

Multiplexed near-infrared <i>in vivo</i> imaging complementarily using quantum dots and upconverting NaYF₄:Yb³⁺,Tm³⁺ nanoparticles

Jeong, Sanghwa,Won, Nayoun,Lee, Jinsik,Bang, Jiwon,Yoo, Jeongsoo,Kim, Sang Geol,Chang, Jeong Ah,Kim, Joonghyun,Kim, Sungjee Royal Society of Chemistry 2011 Chemical communications Vol.47 No.28

<P>A new multiplexed NIR <I>in vivo</I> imaging is showcased by using quantum dots and NaYF<SUB>4</SUB>:Yb<SUP>3+</SUP>,Tm<SUP>3+</SUP> nanoparticles. The ‘temporal’ multiplexing is demonstrated by alternating the excitation wavelengths and unmixing the emissions of different probes. Multiplexed cellular imaging and the cellular trafficking in animal models are shown.</P> <P>Graphic Abstract</P><P>A new multiplexed imaging scheme is demonstrated by alternating the excitation wavelength of quantum dots and NaYF<SUB>4</SUB>:Yb<SUP>3+</SUP>,Tm<SUP>3+</SUP> nanoparticles. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1cc12746b'> </P>

On the synergistic coupling properties of composite CdS/TiO₂ nanoparticle arrays confined in nanopatterned hybrid thin films

Kannaiyan, Dinakaran,Kim, Eunhye,Won, Nayoun,Kim, Kang Wook,Jang, Yoon Hee,Cha, Min-Ah,Ryu, Du Yeol,Kim, Sungjee,Kim, Dong Ha Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.4

<P>Two-dimensional (2D) arrays of hybrid CdS/TiO<SUB>2</SUB> composite nanodots were fabricated on solid substrates using amphiphilic poly(styrene-<I>block</I>-ethylene oxide) diblock copolymer (PS-<I>b</I>-PEO) micelles as templates loaded with CdS nanoparticles (NPs) and TiO<SUB>2</SUB> sol–gel precursors. The inorganic precursors were selectively incorporated into PEO domains of PS-<I>b</I>-PEO due to the specific interactions. The addition of CdS quantum dots (QDs) into thin films of the PS-<I>b</I>-PEO/TiO<SUB>2</SUB> sol–gel mixture led to the morphological changes from mixed wire/hexagonal dot to well-defined, quasi-hexagonal dot arrays. The PS-<I>b</I>-PEO/TiO<SUB>2</SUB>/CdS system showed an enhanced absorption along with red shift behavior in the UV-visible spectral range compared with the PS-<I>b</I>-PEO/TiO<SUB>2</SUB> films. Photoluminescence (PL) studies showed a quenching of CdS emission in the presence of TiO<SUB>2</SUB>. An enhanced photocatalytic degradation of methylene blue (MB) was observed in the hybrid PS-<I>b</I>-PEO/TiO<SUB>2</SUB>/CdS thin film.</P> <P>Graphic Abstract</P><P>Ultrahigh density arrays of composite CdS/TiO<SUB>2</SUB> nanoparticles with enhanced photocatalytic performance were produced by a cooperative sol–gel chemistry and self-assembly of amphiphilic poly(styrene-<I>block</I>-ethylene oxide) block copolymers. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b917858a'> </P>

Long-term Outcome of Extranodal NK/T Cell Lymphoma Patients Treated With Postremission Therapy Using EBV LMP1 and LMP2a-specific CTLs

Cho, Seok-Goo,Kim, Nayoun,Sohn, Hyun-Jung,Lee, Suk Kyeong,Oh, Sang Taek,Lee, Hyun-Joo,Cho, Hyun-Il,Yim, Hyeon Woo,Jung, Seung Eun,Park, Gyeongsin,Oh, Joo Hyun,Choi, Byung-Ock,Kim, Sung Won,Kim, Soo Wh Nature Publishing Group 2015 MOLECULAR THERAPY Vol.23 No.8

<P>Extranodal NK/T-cell lymphoma (ENKTCL) is associated with latent Epstein-Barr virus (EBV) infection and frequent relapse even after complete response (CR) to intensive chemotherapy and radiotherapy. The expression of EBV proteins in the tumor provides targets for adoptive immunotherapy with antigen-specific cytotoxic T cells (CTL). To evaluate the efficacy and safety of EBV latent membrane protein (LMP)-1 and LMP-2a-specific CTLs (LMP1/2a CTLs) stimulated with LMP1/2a RNA-transferred dendritic cells, we treated 10 ENKTCL patients who showed complete response to induction therapy. Patients who completed and responded to chemotherapy, radiotherapy, and/or high-dose therapy followed by stem cell transplantation (HDT/SCT) were eligible to receive eight doses of 2 × 10<SUP>7</SUP> LMP1/2a CTLs/m<SUP>2</SUP>. Following infusion, there were no immediate or delayed toxicities. The 4-year overall survival (OS) and progression-free survival (PFS) were 100%, and 90% (95% CI: 71.4 to 100%) respectively with a median follow-up of 55·5 months. Circulating IFN-γ secreting LMP1 and LMP2a-specific T cells within the peripheral blood corresponded with decline in plasma EBV DNA levels in patients. Adoptive transfer of LMP1/2a CTLs in ENKTCL patients is a safe and effective postremission therapeutic approach. Further randomized studies will be needed to define the role of EBV-CTLs in preventing relapse of ENKTCL.</P>

Selective Fluorogenic and Chromogenic Probe for Detection of Silver Ions and Silver Nanoparticles in Aqueous Media

Chatterjee, Amrita,Santra, Mithun,Won, Nayoun,Kim, Sungjee,Kim, Jae Kyung,Kim, Seung Bin,Ahn, Kyo Han American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.6

<P>A novel rhodamine-based fluorogenic and chromogenic probe for Ag(+) ions in aqueous media is developed, which can be also used for the detection of AgNPs. The sensing mechanism is based on irreversible tandem ring-opening and -forming processes promoted by Ag(+)-coordination to the iodide of the probe, which is accompanied by both color and turn-on type fluorescence changes. The probe shows remarkably high selectivity over other metal ions and detects silver ions up to 14 ppb.</P>

In vivo imaging of cancer cells with electroporation of quantum dots and multispectral imaging

Yoo, Jung Sun,Won, Nayoun,Kim, Hong Bae,Bang, Jiwon,Kim, Sungjee,Ahn, Saeyoung,Soh, Kwang-Sup American Institute of Physics 2010 JOURNAL OF APPLIED PHYSICS - Vol.107 No.12

<P>Our understanding of dissemination and growth of cancer cells is limited by our inability for long-term followup of this process in vivo. Fluorescence molecular imaging has the potential to track cancer cells with high contrast and sensitivity in living animals. For this purpose, intracellular delivery of near-infrared fluorescence quantum dots (QDs) by electroporation offers considerable advantages over organic fluorophores and other cell tagging methods. In this research we developed a multispectral imaging system that could eliminate two major parameters compromising in vivo fluorescence imaging performance, i.e., variations in the tissue optical properties and tissue autofluorescence. We demonstrated that electroporation of QDs and multispectral imaging allowed in vivo assessment of cancer development and progression in the xenograft mouse tumor model for more than 1 month, providing a powerful means to learn more about the biology of cancer and metastasis.</P>

Quantum dot imaging in the second near-infrared optical window: studies on reflectance fluorescence imaging depths by effective fluence rate and multiple image acquisition

Jung, Yebin,Jeong, Sanghwa,Nayoun, Won,Ahn, Boeun,Kwag, Jungheon,Geol Kim, Sang,Kim, Sungjee SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS 2015 JOURNAL OF BIOMEDICAL OPTICS Vol.20 No.4

<P>Quantum dot (QD) imaging capability was investigated by the imaging depth at a near-infrared second optical window (SOW; 1000 to 1400 nm) using time-modulated pulsed laser excitations to control the effective fluence rate. Various media, such as liquid phantoms, tissues, and in vivo small animals, were used and the imaging depths were compared with our predicted values. The QD imaging depth under excitation of continuous 20 mW/cm(2) laser was determined to be 10.3 mm for 2 wt%hemoglobin phantom medium and 5.85 mm for 1 wt% intralipid phantom, which were extended by more than two times on increasing the effective fluence rate to 2000 mW/cm(2). Bovine liver and porcine skin tissues also showed similar enhancement in the contrast-to-noise ratio (CNR) values. A QD sample was inserted into the abdomen of a mouse.With a higher effective fluence rate, the CNR increased more than twofold and the QD sample became clearly visualized, which was completely undetectable under continuous excitation.Multiple acquisitions of QD images and averaging process pixel by pixel were performed to overcome the thermal noise issue of the detector in SOW, which yielded significant enhancement in the imaging capability, showing up to a 1.5 times increase in the CNR.</P>