Bubble-free rapid microfluidic PCR

Lee, Sang Hun,Song, Jihwan,Cho, Byungrae,Hong, SoonGweon,Hoxha, Ori,Kang, Taewook,Kim, Dongchoul,Lee, Luke P. Elsevier 2019 Biosensors & Bioelectronics Vol.126 No.-

<P><B>Abstract</B></P> <P>Microfluidic polymerase chain reaction (PCR) has been of great interest owing to its ability to perform rapid and specific nucleic acid amplification and analysis on small volumes of samples. One of the major drawbacks of microfluidic PCR is bubble generation and reagent evaporation, which can cause malfunctions. Here, through theoretical modeling and characterization of bubble behavior, we propose a bubble-free microfluidic PCR device via controlled fluid transfer. Our approach exploits a thin impermeable polyethylene (PE) top layer that minimizes the generation of bubbles by inhibiting mass transport along a vertical direction. Simulation results demonstrate that a calculated mass flow difference of approximately 370% can be obtained by utilizing an impermeable membrane as the vertical barrier layer. To demonstrate proof-of-concept, two nanoporous polymeric materials, poly(dimethylsiloxane) (PDMS) and PE, were used for stand-alone self-powered sample loading (approximately 70 s) and for use as a vertical barrier layer, respectively. Consequently, we demonstrate successful amplification of the cMET gene, a nucleic acid (NA) biomarker for lung cancer, and complete an ultrafast PCR test in less than 3 min using a high powered Peltier-based thermal cycler under bubble-free conditions. This approach will result in a new paradigm for ultrafast molecular diagnosis and can facilitate NA-based nearly instantaneous diagnostics for point-of-care testing and for personalized and preventive medicine.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The major drawbacks of microfluidic PCR is bubble generation and reagent evaporation. </LI> <LI> A bubble-free microfluidic PCR device via controlled fluid transfer through theoretical modeling and characterization of bubble behavior. </LI> <LI> An impermeable polyethylene layer minimizes the generation of bubbles by inhibiting mass transport along a vertical direction. </LI> <LI> The microfluidic PCR chamber design with surrounding circumferential chamber for a guided-fluid transport of generated bubble. </LI> <LI> Successful nucleic acid amplification of the cMET gene, and an ultrafast PCR test in less than 3 min. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Real-time investigation of cytochrome c release profiles in living neuronal cells undergoing amyloid beta oligomer-induced apoptosis

Lee, Jae Young,Park, Younggeun,Pun, San,Lee, Sung Sik,Lo, Joe F.,Lee, Luke P. The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.23

<P>Intracellular Cyt c release profiles in living human neuroblastoma undergoing amyloid β oligomer (AβO)-induced apoptosis, as a model Alzheimer's disease-associated pathogenic molecule, were analysed in a real-time manner using plasmon resonance energy transfer (PRET)-based spectroscopy.</P>

Asymmetric Nanocrescent Antenna on Upconversion Nanocrystal

Bang, Doyeon,Jo, Eun-Jung,Hong, SoonGweon,Byun, Ju-Young,Lee, Jae Young,Kim, Min-Gon,Lee, Luke P. American Chemical Society 2017 NANO LETTERS Vol.17 No.11

<P>Frequency upconversion activated with lanthanide has attracted attention in various real-world applications, because it is far simpler and more efficient than traditional nonlinear susceptibility-based frequency upconversion, such as second harmonic generation. However, the quantum yield of frequency upconversion of lanthanide-based upconversion nanocrystals remains inefficient for practical applications, and spatial control of upconverted emission is not yet developed. Here, we developed an asymmetric nanocrescent antenna on upconversion nanocrystal (ANAU) to deliver excitation light effectively to the core of upconversion nanocrystal by nanofocusing light and generating asymmetric frequency upconverted emission concentrated toward the tip region. ANAUs were fabricated by high-angle deposition (60 degrees) of gold (Au) on the isolated upconversion nanoparticles supported by nanopillars then moved to refractive-index matched substrate for orientation-dependent upconversion luminescence analysis in the single-nanoparticle scale. We studied shape-dependent nanofocusing efficiency of nanocrescent antennae as a function of the tip-to-tip distance by modulating the deposition angle. The generation of asymmetric frequency upconverted emission toward the tip region was simulated by the asymmetric far-field radiation pattern of dipoles in the nanocrescent antenna and experimentally demonstrated by the orientation-dependent photon intensity of frequency upconverted emission of an ANAU. This finding provides a new way to improve frequency upconversion using an antenna, which locally increases the excitation light and generates the radiation power to certain directions for various applications.</P>

Three-Dimensional Reduced-Symmetry of Colloidal Plasmonic Nanoparticles

Jeong, Eunhye,Kim, Kihoon,Choi, Inhee,Jeong, Sunil,Park, Younggeun,Lee, Hyunjoo,Kim, Soo Hong,Lee, Luke P.,Choi, Yeonho,Kang, Taewook American Chemical Society 2012 NANO LETTERS Vol.12 No.5

<P>Owing to their novel optical properties, three-dimensional plasmonic nanostructures with reduced symmetry such as a nanocrescent and a nanocup have attracted considerable current interest in biophotonic imaging and sensing. However, their practical applications have been still limited since the colloidal synthesis of such structures that allows, in principle, for in vivo application and large-scale production has not been explored yet. To date, these structures have been fabricated only on two-dimensional substrates using micro/nanofabrication techniques. Here we demonstrate an innovative way of breaking symmetry of colloidal plasmonic nanoparticles. Our strategy exploits the direct overgrowth of Au on a hybrid colloidal dimer consisting of Au and polystyrene (PS) nanoparticles without the self-nucleation of Au in an aqueous solution. Upon the overgrowth reaction, the steric crowding of PS leads to morphological evolution of the Au part in the dimer ranging from half-shell, nanocrescent to nanoshell associated with the appearance of the second plasmon absorption band in near IR. Surface-enhanced Raman scattering signal is obtained directly from the symmetry-broken nanoparticles solution as an example showing the viability of the present approach. We believe our concept represents an important step toward a wide range of biophotonic applications for optical nanoplasmonics such as targeting, sensing/imaging, gene delivery, and optical gene regulations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-5/nl300435j/production/images/medium/nl-2012-00435j_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl300435j'>ACS Electronic Supporting Info</A></P>

Shadow Overlap Ion-beam Lithography for Nanoarchitectures

Choi, Yeonho,Hong, Soongweon,Lee, Luke P. American Chemical Society 2009 NANO LETTERS Vol.9 No.11

<P>Precisely constructed nanoscale devices and nanoarchitectures with high spatial resolution are critically needed for applications in high-speed electronics, high-density memory, efficient solar cells, optoelectronics, plasmonics, optical antennas, chemical sensors, biological sensors, and nanospectroscopic imaging. Current methods of classical optical lithography are limited by the diffraction effect of light for nanolithography, and the state of art of e-beam or focused ion beam lithography limit the throughput and further reduction less than few nanometers for large-area batch fabrication. However, these limits can be surpassed surprisingly by utilizing the overlap of two shadow images. Here we present shadow overlap of ion-beam lithography (SOIL), which can combine the advantages of parallel processing, tunable capability of geometries, cost-effective method, and high spatial resolution nanofabrication technique. The SOIL method relies on the overlap of shadows created by the directional metal deposition and etching angles on prepatterned structures. Consequently, highly tunable patterns can be obtained. As examples, unprecedented nanoarchitectures for optical antennas are demonstrated by SOIL. We expect that SOIL can have a significant impact not only on nanoscale devices, but also large-scale (i.e., micro and macro) three-dimensional innovative lithography.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2009/nalefd.2009.9.issue-11/nl901911p/production/images/medium/nl-2009-01911p_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl901911p'>ACS Electronic Supporting Info</A></P>

Additional amplifications of SERS <i>via</i> an optofluidic CD-based platform

Choi, Dukhyun,Kang, Taewook,Cho, Hansang,Choi, Yeonho,Lee, Luke P. Royal Society of Chemistry 2009 Lab on a chip Vol.9 No.2

<P>In this paper, signal amplifications of surface-enhanced Raman scattering (SERS) are realized by an optofluidic compact disc (CD)-based preconcentration method for effective label-free environmental and biomolecular detections. The preconcentration of target molecules is accomplished through the accumulation of adsorbed molecules on SERS-active sites by repeating a ‘filling–drying’ cycle of the assay solution in the optofluidic CD platform. After 30 cycles, the clear and high SERS signal of rhodamine 6G of 1 nM is readily detected. In addition to the preconcentration-based signal amplification by the optofluidic SERS system on the CD platform, we introduce a controlled precipitation of gold nanoparticles by CuSO<SUB>4</SUB> for SERS substrates. This method provides high-throughput, high-sensitive and large-area uniform SERS substrates on the optofluidic CD platform. The uniform SERS signals from different positions in spots of 3 mm<SUP>2</SUP> on the different CDs gives us confidence in the reliability and stability of our SERS substrates.</P> <P>Graphic Abstract</P><P>We present optofluidic SERS on a compact disk (CD) platform which is designed to preconcentrate the molecule of interest <I>via</I> simply repeating ‘filling–drying’ cycles of molecular solutions for SERS signal amplification. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b812067f'> </P>

Asymmetrically Coupled Plasmonic Core and Nanotriplet Satellites

Jo, Hanggochnuri,Yoon, Daesung,Sohn, Ahrum,Kim, Dong-Wook,Choi, Yeonho,Kang, Taewook,Choi, Dukhyun,Kim, Sang-Woo,Lee, Luke P. American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.32

<P>Here, we report asymmetrical multiple electromagnetic coupling of plasmonic core and nanotriplet satellites. Within the plasmonic core and nanotriplet satellites, an enhanced local field is generated which expands across the core due to multiple electromagnetic coupling between a core and nanotriplets. Based on 3D simulations of our plasmonic nanosystem, the overall local field enhancement reaches to over 10<SUP>4</SUP> times, compared with that of a single nanoparticle array. A strong local field distribution across the core to nanotriplets as well as the critical role of the plasmonic core is demonstrated through the 3D simulations. It is proposed that a self-assembled nanotriplet array is completed through two stages of dewetting of a gold thin film on an anodic aluminum oxide (AAO) template. Formation of the core–nanotriplet satellites is significantly influenced by geometrical parameters (i.e., the pore diameter and depth) of the AAO template. Our experimental results show that the local field of our plasmonic nanostructures is amplified up to ∼110 times by adopting a core into the nanotriplet satellites, compared with that of the nanotriplets array without a core. This approach offers a promising strategy for creating an advanced nanoplasmonic platform with strong local field distribution and high-throughput production.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-32/jp505024k/production/images/medium/jp-2014-05024k_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp505024k'>ACS Electronic Supporting Info</A></P>

Graphene Nanopore with a Self-Integrated Optical Antenna

Nam, SungWoo,Choi, Inhee,Fu, Chi-cheng,Kim, Kwanpyo,Hong, SoonGweon,Choi, Yeonho,Zettl, Alex,Lee, Luke P. American Chemical Society 2014 NANO LETTERS Vol.14 No.10

<P>We report graphene nanopores with integrated optical antennae. We demonstrate that a nanometer-sized heated spot created by photon-to-heat conversion of a gold nanorod resting on a graphene membrane forms a nanoscale pore with a self-integrated optical antenna in a single step. The distinct plasmonic traits of metal nanoparticles, which have a unique capability to concentrate light into nanoscale regions, yield the significant advantage of parallel nanopore fabrication compared to the conventional sequential process using an electron beam. Tunability of both the nanopore dimensions and the optical characteristics of plasmonic nanoantennae are further achieved. Finally, the key optical function of our self-integrated optical antenna on the vicinity of graphene nanopore is manifested by multifold fluorescent signal enhancement during DNA translocation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-10/nl503159d/production/images/medium/nl-2014-03159d_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl503159d'>ACS Electronic Supporting Info</A></P>

Ultrafast Photonic PCR and Organoids MAP for Personalized Precision Medicine

Luke P. LEE 한국생물공학회 2019 한국생물공학회 학술대회 Vol.2019 No.4

Bionanoscience for Innovative Global Healthcare Research & Technology

Luke P. LEE 한국생물공학회 2013 한국생물공학회 학술대회 Vol.2013 No.4