Development of a rapid, sensitive, and multiplex pathogen DNA sensor enables early diagnosis and,... more Development of a rapid, sensitive, and multiplex pathogen DNA sensor enables early diagnosis and, subsequently, the proper treatment of infectious diseases, increasing the possibility to save the lives of infected patients. Here, the development of an ultrasensitive and multiplex pathogen DNA detection method that combines a patterned Au nanowire (NW)-on-fi lm surface-enhanced resonance Raman scattering (SERRS) sensor with an exonuclease III-assisted target DNA recycling reaction is reported. Multiple probe DNAs are added to the target DNA solution, and among them, only the complementary probe DNA is selectively digested by exonuclease III, resulting in the decrease in its concentration. The digestion process is repeated by recycling of target DNAs. The decrease of the complementary probe DNA concentration is detected by SERRS. Combining the high sensitivity of the NW-on-film sensor and the target recycling reaction signifi cantly improves DNA detection performance, resulting in the detection limit of 100 f M corresponding to 3 amole. By positioning Au NWs at specifi c addresses, multiple pathogen DNAs can be identified in a single step. Clinical sample tests with multiple genomic DNAs of pathogens show the potential of this sensor for practical diagnosis of infectious diseases.
We show that the multiplicative product of a molecular-beam excitation spectrum and an ultracold-... more We show that the multiplicative product of a molecular-beam excitation spectrum and an ultracold-molecule excitation spectrum, with a frequency offset appropriate to the initial ultracold-molecule level, provides the relative rate of stimulated Raman transfer (SRT) from a given high rovibrational level to the lowest rovibronic level, i.e., the v = 0,J = 0 level of the ground electronic state for photoassociated (and magnetoassociated) ultracold molecules. This product spectrum clearly indicates the optimal pathways for SRT, even when the two component spectra are completely unassigned. We illustrate this specifically for the case of KRb.
Surface-enhanced Raman scattering (SERS) of graphene on a
SiO2ACHTUNGTRENUNG(300 nm)/Si substrat... more Surface-enhanced Raman scattering (SERS) of graphene on a
SiO2ACHTUNGTRENUNG(300 nm)/Si substrate was investigated by depositing Au nanoparticles using thermal evaporation. This provideda maximum enhancement of 120
times for single-layer graphene at 633 nm excitation. SERS spectra andscan images of single-layer and fewlayer graphene were acquired. Singlelayer graphene provides much larger SERS enhancement compared to fewlayergraphene, while in single-layer graphene the enhancement of the G
band was larger than that of the 2D band. Furthermore, the D bands were identified in the SERS spectra; these bands were not observed in a normal Raman spectrum without Au deposition. Appearance of the D band is ascribed to the considerable SERS enhancement and not to an Au deposition- induced defect. Lastly, SERS enhancement of graphene on a transparent glass substrate was compared with
that on the SiO2ACHTUNGTRENUNG(300 nm)/Si substrate to exclude enhancement by multiple reflections between the Si substrate and deposited Au nanoparticles. The contribution of multiple reflections to total enhancement on the SiO2- ACHTUNGTRENUNG(300 nm)/Si substrate was 1.6 times outof average SERS enhancement factor, 71 times.
We report an ultrasensitive and selective single nanowire-on-film (SNOF) surface-enhanced resonan... more We report an ultrasensitive and selective single nanowire-on-film (SNOF) surface-enhanced resonance Raman scattering (SERRS) sensor for Hg2+ detection based on structureswitching double stranded DNAs (dsDNAs). Binding of Hg2+ induces conformational changes of the dsDNAs and let a Raman reporter get close to the SNOF structure, thereby turning on SERRS signal. The well-defined SNOF structure provides a detection limit of 100 pm with improved accuracy in Hg2+ detection. This sensor is stable
over a considerable amount of time and reusable after simple treatment. Since this SNOF sensor is composed of
a single Au NW on a film, development of a multiplex sensor would be possible by employing NWs modified by multiple
kinds of aptamers.
Development of a rapid, sensitive, and multiplex pathogen DNA sensor enables early diagnosis and,... more Development of a rapid, sensitive, and multiplex pathogen DNA sensor enables early diagnosis and, subsequently, the proper treatment of infectious diseases, increasing the possibility to save the lives of infected patients. Here, the development of an ultrasensitive and multiplex pathogen DNA detection method that combines a patterned Au nanowire (NW)-on-fi lm surface-enhanced resonance Raman scattering (SERRS) sensor with an exonuclease III-assisted target DNA recycling reaction is reported. Multiple probe DNAs are added to the target DNA solution, and among them, only the complementary probe DNA is selectively digested by exonuclease III, resulting in the decrease in its concentration. The digestion process is repeated by recycling of target DNAs. The decrease of the complementary probe DNA concentration is detected by SERRS. Combining the high sensitivity of the NW-on-film sensor and the target recycling reaction signifi cantly improves DNA detection performance, resulting in the detection limit of 100 f M corresponding to 3 amole. By positioning Au NWs at specifi c addresses, multiple pathogen DNAs can be identified in a single step. Clinical sample tests with multiple genomic DNAs of pathogens show the potential of this sensor for practical diagnosis of infectious diseases.
We show that the multiplicative product of a molecular-beam excitation spectrum and an ultracold-... more We show that the multiplicative product of a molecular-beam excitation spectrum and an ultracold-molecule excitation spectrum, with a frequency offset appropriate to the initial ultracold-molecule level, provides the relative rate of stimulated Raman transfer (SRT) from a given high rovibrational level to the lowest rovibronic level, i.e., the v = 0,J = 0 level of the ground electronic state for photoassociated (and magnetoassociated) ultracold molecules. This product spectrum clearly indicates the optimal pathways for SRT, even when the two component spectra are completely unassigned. We illustrate this specifically for the case of KRb.
Surface-enhanced Raman scattering (SERS) of graphene on a
SiO2ACHTUNGTRENUNG(300 nm)/Si substrat... more Surface-enhanced Raman scattering (SERS) of graphene on a
SiO2ACHTUNGTRENUNG(300 nm)/Si substrate was investigated by depositing Au nanoparticles using thermal evaporation. This provideda maximum enhancement of 120
times for single-layer graphene at 633 nm excitation. SERS spectra andscan images of single-layer and fewlayer graphene were acquired. Singlelayer graphene provides much larger SERS enhancement compared to fewlayergraphene, while in single-layer graphene the enhancement of the G
band was larger than that of the 2D band. Furthermore, the D bands were identified in the SERS spectra; these bands were not observed in a normal Raman spectrum without Au deposition. Appearance of the D band is ascribed to the considerable SERS enhancement and not to an Au deposition- induced defect. Lastly, SERS enhancement of graphene on a transparent glass substrate was compared with
that on the SiO2ACHTUNGTRENUNG(300 nm)/Si substrate to exclude enhancement by multiple reflections between the Si substrate and deposited Au nanoparticles. The contribution of multiple reflections to total enhancement on the SiO2- ACHTUNGTRENUNG(300 nm)/Si substrate was 1.6 times outof average SERS enhancement factor, 71 times.
We report an ultrasensitive and selective single nanowire-on-film (SNOF) surface-enhanced resonan... more We report an ultrasensitive and selective single nanowire-on-film (SNOF) surface-enhanced resonance Raman scattering (SERRS) sensor for Hg2+ detection based on structureswitching double stranded DNAs (dsDNAs). Binding of Hg2+ induces conformational changes of the dsDNAs and let a Raman reporter get close to the SNOF structure, thereby turning on SERRS signal. The well-defined SNOF structure provides a detection limit of 100 pm with improved accuracy in Hg2+ detection. This sensor is stable
over a considerable amount of time and reusable after simple treatment. Since this SNOF sensor is composed of
a single Au NW on a film, development of a multiplex sensor would be possible by employing NWs modified by multiple
kinds of aptamers.
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Papers by bongsoo kim
SiO2ACHTUNGTRENUNG(300 nm)/Si substrate was investigated by depositing Au nanoparticles using thermal evaporation. This provideda maximum enhancement of 120
times for single-layer graphene at 633 nm excitation. SERS spectra andscan images of single-layer and fewlayer graphene were acquired. Singlelayer graphene provides much larger SERS enhancement compared to fewlayergraphene, while in single-layer graphene the enhancement of the G
band was larger than that of the 2D band. Furthermore, the D bands were identified in the SERS spectra; these bands were not observed in a normal Raman spectrum without Au deposition. Appearance of the D band is ascribed to the considerable SERS enhancement and not to an Au deposition- induced defect. Lastly, SERS enhancement of graphene on a transparent glass substrate was compared with
that on the SiO2ACHTUNGTRENUNG(300 nm)/Si substrate to exclude enhancement by multiple reflections between the Si substrate and deposited Au nanoparticles. The contribution of multiple reflections to total enhancement on the SiO2- ACHTUNGTRENUNG(300 nm)/Si substrate was 1.6 times outof average SERS enhancement factor, 71 times.
over a considerable amount of time and reusable after simple treatment. Since this SNOF sensor is composed of
a single Au NW on a film, development of a multiplex sensor would be possible by employing NWs modified by multiple
kinds of aptamers.
SiO2ACHTUNGTRENUNG(300 nm)/Si substrate was investigated by depositing Au nanoparticles using thermal evaporation. This provideda maximum enhancement of 120
times for single-layer graphene at 633 nm excitation. SERS spectra andscan images of single-layer and fewlayer graphene were acquired. Singlelayer graphene provides much larger SERS enhancement compared to fewlayergraphene, while in single-layer graphene the enhancement of the G
band was larger than that of the 2D band. Furthermore, the D bands were identified in the SERS spectra; these bands were not observed in a normal Raman spectrum without Au deposition. Appearance of the D band is ascribed to the considerable SERS enhancement and not to an Au deposition- induced defect. Lastly, SERS enhancement of graphene on a transparent glass substrate was compared with
that on the SiO2ACHTUNGTRENUNG(300 nm)/Si substrate to exclude enhancement by multiple reflections between the Si substrate and deposited Au nanoparticles. The contribution of multiple reflections to total enhancement on the SiO2- ACHTUNGTRENUNG(300 nm)/Si substrate was 1.6 times outof average SERS enhancement factor, 71 times.
over a considerable amount of time and reusable after simple treatment. Since this SNOF sensor is composed of
a single Au NW on a film, development of a multiplex sensor would be possible by employing NWs modified by multiple
kinds of aptamers.