Ji-Young Kim

Hyon-Gyu Park

Sang Hun Han

Byung-Ho Kim

Bo-In Park

Jongseok Jung

P. Abdul Rasheed

Jin Ock Park

Ju-Hwan Oh

Sohyun Seo

Jang Ho Joo

Hye In Cho

Yan Li

Seung Yeon Seo

Yoon Hyuck Kim

Won Kyu Lee

Han-Jung Ryu

Our research goals are (1) to develop systematic approaches to synthesize materials at the nanometer and micrometer scales, (2) to functionalize them to provide unique chemical and physical properties, and (3) to use the materials for a variety of biodiagnostic and therapeutic applications.

나노미터 및 마이크로미터 스케일에서 재료를 합성하는 체계적인 접근법을 개발하고, 고유한 화학적 및 물리적 특성을 제공하기 위해 재료를 기능화하며, 다양한 생체 진단 및 치료 응용 분야에 재료를 사용하는 것이 우리의 연구 목표입니다.

Publications

Colorimetric Detection of Mercuric Ion (Hg2+) in Aqueous Media using DNA‐Functionalized Gold Nanoparticles

Silver nanoparticle-oligonucleotide conjugates based on DNA with triple cyclic disulfide moieties

A DNA− gold nanoparticle-based colorimetric competition assay for the detection of cysteine

Multiplexed detection of protein cancer markers with biobarcoded nanoparticle probes

Nanoparticle-based bio-barcode assay redefines “undetectable” PSA and biochemical recurrence after radical prostatectomy

Synthesis of mesoporous silicas of controlled pore wall thickness and their replication to ordered nanoporous carbons with various pore diameters

Colorimetric nitrite and nitrate detection with gold nanoparticle probes and kinetic end points

Three-layer composite magnetic nanoparticle probes for DNA

Gold, poly (β-amino ester) nanoparticles for small interfering RNA delivery

Multiplexed DNA detection with biobarcoded nanoparticle probes

Imaging deep within a scattering medium using collective accumulation of single-scattered waves

Chip-based scanometric detection of mercuric ion using DNA-functionalized gold nanoparticles

Recent advances in optical detection of dopamine using nanomaterials

Synthesis and thermally reversible assembly of DNA− gold nanoparticle cluster conjugates

DNA-induced size-selective separation of mixtures of gold nanoparticles

Structures of DNA-linked nanoparticle aggregates

Designed hybridization properties of DNA–gold nanoparticle conjugates for the ultraselective detection of a single-base mutation in the breast cancer gene BRCA1

Deep eutectic solvents as versatile media for the synthesis of noble metal nanomaterials

Insights into characterization methods and biomedical applications of nanoparticle–protein corona

Thermodynamically controlled separation of polyvalent 2-nm gold nanoparticle-oligonucleotide conjugates

Jae-Seung Lee

Color is everything: Hg2+ in aqueous media is detected by the formation of thymidine-Hg2+-thymidine coordination complexes, which raises the melting temperature of the DNA-hybridized gold nanoparticle probes and thus the temperature at which the probes disperse and effect a purple-to-red color change. The method has very high sensitivity and selectivity, and it provides a simple and fast colorimetric readout (see picture). (Figure Presented) © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

We report a new strategy for preparing silver nanoparticle−oligonucleotide conjugates that are based upon DNA with cyclic disulfide-anchoring groups. These particles are extremely stable and can withstand NaCl concentrations up to 1.0 M. When silver nanoparticles functionalized with complementary sequences are combined, they assemble to form DNA-linked nanoparticle networks. This assembly process is reversible with heating and is associated with a red shifting of the particle surface plasmon resonance and a concomitant color change from yellow to pale red. Analogous to the oligonucleotide-functionalized gold nanoparticles, these particles also exhibit highly cooperative binding properties with extremely sharp melting transitions. This work is an important step toward using silver nanoparticle−oligonucleotide conjugates for a variety of purposes, including molecular diagnostic labels, synthons in …

We report the development of a highly sensitive and selective colorimetric detection method for cysteine based upon oligonucleotide-functionalized gold nanoparticle probes that contain strategically placed thymidine−thymidine (T−T) mismatches complexed with Hg 2+ . This assay relies upon the distance-dependent optical properties of gold nanoparticles, the sharp melting transition of oligonucleotide-linked nanoparticle aggregates, and the very selective coordination of Hg 2+ with cysteine. The concentration of cysteine can be determined by monitoring with the naked eye or a UV−vis spectrometer the temperature at which the purple-to-red color change associated with aggregate dissociation takes place. This assay does not utilize organic cosolvents, enzymatic reactions, light-sensitive dye molecules, lengthy protocols, or sophisticated instrumentation thereby overcoming some of the limitations of more …

We have developed the chemistry for preparing a universal probe and the appropriate nano- and microparticle labels that can be used to do highly selective multiplexed detection of three protein cancer markers at low-femtomolar concentration in buffer and serum media. The approach relies on a new multiplexed version of the biobarcode amplification method and offers new opportunities for studying multiple protein markers in a single sample. This could lead to new forms of disease diagnosis and monitoring disease recurrence in a variety of settings.

We report the development of a previously undescribed gold nanoparticle bio-barcode assay probe for the detection of prostate specific antigen (PSA) at 330 fg/mL, automation of the assay, and the results of a clinical pilot study designed to assess the ability of the assay to detect PSA in the serum of 18 men who have undergone radical prostatectomy for prostate cancer. Due to a lack of sensitivity, available PSA immunoassays are often not capable of detecting PSA in the serum of men after radical prostatectomy. This new bio-barcode PSA assay is ≈300 times more sensitive than commercial immunoassays. Significantly, with the barcode assay, every patient in this cohort had a measurable serum PSA level after radical prostatectomy. Patients were separated into categories based on PSA levels as a function of time. One group of patients showed low levels of PSA with no significant increase with time and did not …

A synthesis strategy for the systematic control of the pore wall thickness has been developed for the mesoporous silicas with 2-D hexagonal order using ionic and nonionic surfactant mixtures. The mesoporous silicas have been used as templates for the synthesis of 2-D hexagonally ordered mesoporous carbons with controlled pore diameters. The synthesis strategy and results are useful not only for tailoring the properties of the mesoporous materials but also for extending our insights into the synthesis mechanism.

We report the development of a novel colorimetric nitrite and nitrate ion assay based upon gold nanoparticle probes functionalized with Griess reaction reagents. This assay takes advantage of the distance-dependent plasmonic properties of the gold nanoparticles and the ability of nitrite ion to facilitate the cross coupling of novel nanoparticle probes modified with aniline and naphthalene moieties. The assay works on the concept of a kinetic end point and can be triggered at the EPA limit for this ion in drinking water (highlighted in red, μM). This rapid and simple assay could be useful for on-site water quality monitoring.

A method for synthesizing composite nanoparticles with a gold shell, an Fe 3 O 4 inner shell, and a silica core has been developed. The approach utilizes positively charged amino-modified SiO 2 particles as templates for the assembly of negatively charged 15 nm superparamagnetic water-soluble Fe 3 O 4 nanoparticles. The SiO 2 −Fe 3 O 4 particles electrostatically attract 1−3 nm Au nanoparticle seeds that act in a subsequent step as nucleation sites for the formation of a continuous gold shell around the SiO 2 −Fe 3 O 4 particles upon HAuCl 4 reduction. The three-layer magnetic nanoparticles, when functionalized with oligonucleotides, exhibit the surface chemistry, optical properties, and cooperative DNA binding properties of gold nanoparticle probes, but the magnetic properties of the Fe 3 O 4 inner shell.

The safe and effective delivery of RNA therapeutics remains the major barrier to their broad clinical application. Here we develop a new nanoparticulate delivery system based on inorganic particles and biodegradable polycations. First, gold nanoparticles were modified with the hydrophilic polymer poly(ethylene glycol) (PEG), and then small interfering RNA (siRNA) was conjugated to the nanoparticles via biodegradable disulfide linkages, with ∼30 strands of siRNA per nanoparticle. The particles were then coated with a library of end-modified poly(β-amino ester)s (PBAEs), previously identified as capable of facilitating intracellular DNA delivery. Nanoparticulate formulations developed here facilitate high levels of in vitro siRNA delivery, facilitating delivery as good or better than the commercially available lipid reagent, Lipofectamine 2000.

High-throughput multiplexed DNA detection is important for gene-expression profiling, as well as the detection of singlenucleotide polymorphism and pathogens such as common infectious diseases and biowarfare agents.[1] DNA microarrays utilize fluorescence readout and have become a core technology for the parallel interrogation of a large number of nucleic acid sequences.[1, 2] However, microarray technology coupled with molecular fluorophore probes has limitations; these include the necessity for target amplification, postamplification fluorophore labeling, slow binding kinetics between target sequence and capture strand, and in the case of multiplexed analysis, overlapping spectral features of the fluorophores, nonuniform photobleaching rates, the need for multiple-laser excitation sources, and complex, expensive instrumentation. The quest for improved and uniform labeling and detection methodologies has led to the development of alternative approaches such as fluorophore-labeled dendrimers,[3] fluorophore-encoded microspheres,[4] optically encoded porous silicon photonic crystals,[5] multimetal microrods,[6] nanowires,[7] and metal and semiconductor nanoparticle labels.[8] Oligonucleotide-functionalized gold nanoparticles (Au NPs) have a demonstrated advantage in terms of sensitivity and selectivity over conventional probes in a variety of biodetection schemes.[8a–c, 9] Their outstanding performance stems from cooperative binding properties, unique optical properties, catalytic properties, and the existence of robust and versatile surface-functionalization methods.[10] The biobarcode assay is based on Au NPs …

Optical microscopy suffers from a loss of resolving power when imaging targets are embedded in thick scattering media because of the dominance of strong multiple-scattered waves over waves scattered only a single time by the targets. Here, we present an approach that maintains full optical resolution when imaging deep within scattering media. We use both time-gated detection and spatial input–output correlation to identify those reflected waves that conserve in-plane momentum, which is a property of single-scattered waves. By implementing a superradiance-like collective accumulation of the single-scattered waves, we enhance the ratio of the single scattering signal to the multiple scattering background by more than three orders of magnitude. An imaging depth of 11.5 times the scattering mean free path is achieved with a near-diffraction-limited resolution of 1.5 μm. Our method of distinguishing single- from …

We have developed a chip-based scanometric method for the detection of mercuric ion (Hg 2+ ). This method takes advantage of the cooperative binding and catalytic properties of DNA-functionalized gold nanoparticles and the selective binding of a thymine−thymine mismatch for Hg 2+ . The limit of detection of this assay in buffer and environmentally relevant samples (lake water) is 10 nM (2 ppb) Hg 2+ , which is the U.S. Environmental Protection Agency (EPA) limit of [Hg 2+ ] for drinkable water and 1 order of magnitude lower than previous colorimetric assays. This assay is capable of discriminating Hg 2+ from 15 other environmentally relevant metal ions. The method is attractive for potential point-of-use applications due to its high throughput, convenient readout, and portability.

This review (with 121 references) gives a summary on recent advances in the use of nanomaterials for the optical determination of dopamine. It includes a brief overview of the clinical significance of dopamine followed by a discussion on the recent advances in various nanomaterial-based distinctive optical spectroscopic methods such as (a) colorimetry and spectrophotometry, (b) surface-enhanced Raman spectroscopy (SERS), (c) fluorescence spectrometry, and (d) electrochemiluminescence (ECL) spectrometry. All sections are further divided into subsections based on the type of nanomaterial used, and their advantages and disadvantages are discussed. A discussion on the validity of the nanomaterial-based optical detection of dopamine for human samples is also included. This review concludes with highlights of current challenges of nanomaterial-based optical sensors and an outlook on future perspectives …

We describe the facile synthesis of stable gold nanoparticle clusters densely functionalized with DNA (DNA−AuNP clusters) using dithiothreitol and monothiol DNA and their thermally reversible assembly properties. The size of the clusters exhibits a very narrow distribution and can be easily controlled by adjusting the stoichiometry of dithiothreitol and DNA, leading to a variety of colors due to the surface plasmon resonance of the AuNP clusters. Importantly, the DNA−AuNP clusters exhibit highly cooperative melting properties with distinctive and diverse color changes depending on their size. The selective and sensitive colorimetric detection of target sequences was demonstrated based upon the unique properties of the DNA−AuNP clusters.

We present a novel method for size-selectively separating mixtures of nanoparticles in aqueous media utilizing the inherent chemical recognition properties of DNA and the cooperative binding properties of DNA-functionalized gold nanoparticles. We have determined that the melting temperatures ( T m s) of aggregates formed from nanoparticles interconnected by duplex DNA are dependent upon particle size. This effect is proposed to derive from larger contact areas between the larger particles and therefore increased cooperativity, leading to higher T m s. The separation protocol involves taking two aliquots of a mixture of particles that vary in size and functionalizing them with complementary DNA. These aliquots are mixed at a temperature above the T m for aggregates formed from the smaller particles but below the T m for aggregates formed from the larger particles. Therefore, the aggregates that form consist …

The room-temperature structure of DNA-linked gold nanoparticle aggregates is investigated using a combination of experiment and theory. The experiments involve extinction spectroscopy measurements and dynamic light scattering measurements of aggregates made using 60 and 80 nm gold particles and 30 base-pair DNA. The theoretical studies use calculated spectra for models of the aggregate structures to determine which structure matches the observations. These models include diffusion-limited cluster-cluster aggregation (DLCA), reaction-limited cluster-cluster aggregation (RLCA), and compact (nonfractal) cluster aggregation. The diameter of the nanoparticles used in the experiments is larger than has been considered previously, and this provides greater sensitivity of spectra to aggregate structure. We show that the best match between experiment and theory occurs for the RLCA fractal structures. This …

We have investigated the hybridization properties of DNA–gold nanoparticle conjugates and have discovered that the hybridization properties are dramatically affected by controlling various synthetic and environmental conditions. We have further demonstrated that moderate DNA loading instead of high loading per nanoparticle significantly enhances the hybridization rates of DNA–gold nanoparticle conjugates, which allows one to precisely design their hybridization properties to distinguish a single-nucleotide polymorphism (SNP). A diagnostic application for the colorimetric detection of an SNP associated with a mutation in the breast cancer gene BRCA1 has been carefully designed and demonstrated.

Deep eutectic solvents (DESs) were developed 15 years ago and have been used for various purposes based on their unique chemical and physical properties. Recently, they have been highlighted as versatile media for the synthesis of noble metal nanomaterials. Although there are a few limitations, their vast chemical library of hydrogen bond donors and excellent solubility show great potential for their future applications for the synthesis of noble metal nanoparticles.

Nanoparticles (NPs) exposed to a biological milieu will strongly interact with proteins, forming “coronas” on the surfaces of the NPs. The protein coronas (PCs) affect the properties of the NPs and provide a new biological identity to the particles in the biological environment. The characterization of NP-PC complexes has attracted enormous research attention, owing to the crucial effects of the properties of an NP-PC on its interactions with living systems, as well as the diverse applications of NP-PC complexes. The analysis of NP-PC complexes without a well-considered approach will inevitably lead to misunderstandings and inappropriate applications of NPs. This review introduces methods for the characterization of NP-PC complexes and investigates their recent applications in biomedicine. Furthermore, the review evaluates these characterization methods based on comprehensive critical views and provides future perspectives regarding the applications of NP-PC complexes.

We describe the synthesis of small (2-nm diameter) gold nanoparticles densely functionalized with thiolated DNA (DNA-Au NPs) and a method to separate these particles from excess free DNA after synthesis. The separation method utilizes the thermodynamically enhanced binding properties of 2-nm DNA-Au NPs, compared to free excess DNA, to selectively hybridize these small particles to larger (15-nm diameter) DNA-Au NPs and form aggregates that can be isolated by simple centrifugation. These 2-nm DNA-Au NPs are obtained in a 46% overall yield, have a high surface coverage of DNA (64.8 ± 6.4 pmol/cm 2 ), and as a result, exhibit increased melting temperatures and cooperative melting properties.

The JSLee Group in KU

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