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Raman Multiplexers For Alternative Gene Splicing, Lan Sun, Chenxu Yu, Joseph Irudayaraj
Raman Multiplexers For Alternative Gene Splicing, Lan Sun, Chenxu Yu, Joseph Irudayaraj
Chenxu Yu
Nonfluorescent labels were used for an array-format multiplex detection of alternative splice junctions of breast cancer susceptibility gene 1 (BRCA1) by surface-enhanced Raman scattering (SERS). A four-plex detection scheme using nonfluorescent labels was demonstrated for DNA sequences specific to four BRCA1 alternative splice variants: Δ(11q) (the last 3309 nt deleted from exon 11), Δ(9, 10) (exon 9 and 10 deleted), Δ(5) (exon 5 deleted), and Δ(5q, 6) (the last 22 nt of exon 5 and the entire exon 6 is deleted). This is the first proof-of-concept study to apply SERS-based detection using nonfluorescent labels to investigate alternative gene splicing. Detection …
Surface Modification Of Cetyltrimethylammonium Bromide-Capped Gold Nanorods To Make Molecular Probes, Chenxu Yu, Leo Varghese, Joseph Irudayaraj
Surface Modification Of Cetyltrimethylammonium Bromide-Capped Gold Nanorods To Make Molecular Probes, Chenxu Yu, Leo Varghese, Joseph Irudayaraj
Chenxu Yu
A chemical procedure to replace the cetyltrimethylammonium bromide (CTAB) cap on gold nanorods (GNRs) fabricated through seed-mediated growth with organothiol compounds [3-animo-5-mercapto-1,2,4-triazole (AMTAZ) and 11-mercaptoundecaonic acid (MUDA)] was developed to reduce the cytotoxity of GNRs and facilitate further biofunctionalization. Compared to phosphatidylcholine (PC) modification, our procedure yields stable GNRs that are biocompatible and suitable for whole-cell studies. The PC-, AMTAZ-, and MUDA-activated GNRs all showed low cytotoxicity. By choosing different organothiols, net positive or negative charges could be created on the nanorod surface, for different applications. Gold nanorod molecular probes (GNrMPs) were fabricated by subsequent attachment of antibodies to the …
Identity Profiling Of Cell Surface Markers By Multiplex Gold Nanorod Probes, Chenxu Yu, Harikrishna Nakshatri, Joseph Irudayaraj
Identity Profiling Of Cell Surface Markers By Multiplex Gold Nanorod Probes, Chenxu Yu, Harikrishna Nakshatri, Joseph Irudayaraj
Chenxu Yu
Gold nanorod molecular probes (GNrMPs) were designed and fabricated for multiplex identification of cell surface markers in HBECs. Cells were probed directly using dark field microscopy integrated with a spectral imager for simultaneous detection of up to three surface markers. The immunophenotype composition of these cell lines indicative of their metastasis potential was assessed using the GNrMPs. The technique has the potential to become an important tool for diagnosis and prognosis of breast and other cancers.
Surface-Enhanced Raman Scattering Based Nonfluorescent Probe For Multiplex Dna Detection, Lan Sun, Chenxu Yu, Joseph Irudayaraj
Surface-Enhanced Raman Scattering Based Nonfluorescent Probe For Multiplex Dna Detection, Lan Sun, Chenxu Yu, Joseph Irudayaraj
Chenxu Yu
To provide rapid and accurate detection of DNA markers in a straightforward, inexpensive, and multiplex format, an alternative surface-enhanced Raman scattering based probe was designed and fabricated to covalently attach both DNA probing sequence and nonfluorescent Raman tags to the surface of gold nanoparticles (DNA-AuP-RTag). The intensity of Raman signal of the probes could be controlled through the surface coverage of the nonfluorescent Raman tags (RTags). Detection sensitivity of these probes could be optimized by fine-tuning the amount of DNA molecules and RTags on the probes. Long-term stability of the DNA-AuP-RTag probes was found to be good (over 3 months). …
Multiplex Biosensor Using Gold Nanorods, Chenxu Yu, Joseph Irudayaraj
Multiplex Biosensor Using Gold Nanorods, Chenxu Yu, Joseph Irudayaraj
Chenxu Yu
Gold nanorods (GNRs) with different aspect ratios were fabricated through seed-mediated growth and surface activation by alkanethiols for the attachment of antibodies to yield gold nanorod molecular probes (GNrMPs). Multiplex sensing was demonstrated by the distinct response of the plasmon spectra of the GNrMPs to binding events of three targets (goat anti-human IgG1 Fab, rabbit anti-mouse IgG1 Fab, rabbit anti-sheep IgG (H+L)). Plasmonic sensors are highly specific and sensitive and can be used to monitor refractive index changes caused by molecular interactions in their immediate vicinity with potential to achieve single-particle biosensing. This technique can play a key role in …
Mid-Ir Biosensor: Detection And Fingerprinting Of Pathogens On Gold Island Functionalized Chalcogenide Films, Chenxu Yu, Ashtosh Ganjoo, H. Jain, C. G. Pantano, Joseph Irudayaraj
Mid-Ir Biosensor: Detection And Fingerprinting Of Pathogens On Gold Island Functionalized Chalcogenide Films, Chenxu Yu, Ashtosh Ganjoo, H. Jain, C. G. Pantano, Joseph Irudayaraj
Chenxu Yu
Antibody (human IgG, anti-E. coli O157:H7, and anti-Salmonella) complexes on the surface of IR-transparent Ge-containing chalcogenide glass films were formed via thiol chemistry on 20-nm-thick gold islands. As a first step, the protocol was validated by monitoring fluorescently tagged targets to validate binding. FT-IR spectroscopy confirmed that the coating of the films with 20-nm gold did not have a significant effect on the propagation and penetration of IR evanescent waves through the film. The films functionalized with anti-E. coli O157:H7 and anti-Salmonella antibodies were used to detect E. coli O157:H7 and S. enteriditis through label-free IR fingerprinting. Highly selective detection …
Identification Of Pathogenic Bacteria In Mixed Cultures By Ftir Spectroscopy, Chenxu Yu, Joseph Irudayaraj
Identification Of Pathogenic Bacteria In Mixed Cultures By Ftir Spectroscopy, Chenxu Yu, Joseph Irudayaraj
Chenxu Yu
Routine identification of pathogenic microorganisms predominantly based on nutritional and biochemical tests is a time-consuming process. In this study, a method based on FTIR spectroscopy was developed to detect and identify the presence of five possible pathogenic bacteria in ten different microorganism mixtures with each cocktail containing up to three different species at a concentration of 109 CFU/mL. A mathematical approach based on factoring out the common features in the spectral fingerprints was developed and implemented in conjunction with discriminant analysis. FTIR spectra of the mixtures were directly obtained and analyzed using canonical variate analysis based on the discriminant model …