A facile method for fabrication of buckled PDMS silver nanorod arrays as active 3D SERS cages for bacterial sensing

Kumar, Samir; Lodhi, Devesh K.; Goel, Pratibha; Neeti, Neeti; Mishra, Prashant; Singh, Jaspal

doi:10.1039/c5cc03604f

Cited by 79 publications

(41 citation statements)

References 39 publications

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“…4a shows the representative Raman spectra of two bacteria on the surface of the membrane. Three Raman transitions for both bacteria are commonly observed at 717 cm −1 , 958 cm −1 , and 1351 cm −1 , which correspond to a glycosidic ring mode, ν (CN), and ν (COO − ), respectively 17 – 20 . Note that the structure of the cell membrane that is responsible for the observed SERS signals is similar for both bacteria as they are gram-negative 35 .…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, nanostructure-based optical methods have gained increasing attention because of their high sensitivity and rapid detection time 10 – 22 . Among them, surface-enhanced Raman spectroscopy (SERS) is particularly attractive for the ultrasensitive detection of bacteria 17 – 22 . Metallic nanostructures, including colloidal nanoparticles modified with specific antibodies or Raman active dyes or magnetic nanoparticles for the enrichment of bacteria, have also been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

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Plasmonic bacteria on a nanoporous mirror via hydrodynamic trapping for rapid identification of waterborne pathogens

et al. 2018

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A rapid, precise method for identifying waterborne pathogens is critically needed for effective disinfection and better treatment. However, conventional methods, such as culture-based counting, generally suffer from slow detection times and low sensitivities. Here, we developed a rapid detection method for tracing waterborne pathogens by an innovative optofluidic platform, a plasmonic bacteria on a nanoporous mirror, that allows effective hydrodynamic cell trapping, enrichment of pathogens, and optical signal amplifications. We designed and simulated the integrated optofluidic platform to maximize the enrichment of the bacteria and to align bacteria on the nanopores and plasmonic mirror via hydrodynamic cell trapping. Gold nanoparticles are self-assembled to form antenna arrays on the surface of bacteria, such as Escherichia coli and Pseudomonas aeruginosa, by replacing citrate with hydroxylamine hydrochloride in order to amplify the signal of the plasmonic optical array. Owing to the synergistic contributions of focused light via the nanopore geometry, self-assembled nanoplasmonic optical antennas on the surface of bacteria, and plasmonic mirror, we obtain a sensitivity of detecting E. coli as low as 102 cells/ml via surface-enhanced Raman spectroscopy. We believe that our label-free strategy via an integrated optofluidic platform will pave the way for the rapid, precise identification of various pathogens.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Plasmonic bacteria on a nanoporous mirror via hydrodynamic trapping for rapid identification of waterborne pathogens

et al. 2018

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“…Kumar et al fabricated a 3D flexible SERS substrate by depositing AgNPs on structured polydimethylsiloxane using a Taro leaf as the template to detect malachite green [16]. Kumar et al fabricated a buckled PDMS silver nanorods array as an active 3D SERS sensor for detecting bacteria [17]. Despite demonstrating enormous application prospects for real sample detection, these flexible substrates still involve unresolved issues regarding metal-molecule contact and metal particle oxidation, both of which can cause poor reproducibility and stability in SERS detection [17,18].…”

Section: Introductionmentioning

confidence: 99%

3D Ultrasensitive Polymers-Plasmonic Hybrid Flexible Platform for In-Situ Detection

Zhang

et al. 2020

Polymers

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This paper introduces a three-dimensional (3D) pyramid to the polymers-plasmonic hybrid structure of polymethyl methacrylate (PMMA) composite silver nanoparticle (AgNPs) as a higher quality flexible surface-enhanced Raman scattering (SERS) substrate. Benefiting from the effective oscillation of light inside the pyramid valley could provide wide distributions of 3D “hot spots” in a large space. The inclined surface design of the pyramid structure could facilitate the aggregation of probe molecules, which achieves highly sensitive detection of rhodamine 6G (R6G) and crystal violet (CV). In addition, the AgNPs and PMMA composite structures provide uniform space distribution for analyte detection in a designated hot spot zone. The incident light can penetrate the external PMMA film to trigger the localized plasmon resonance of the encapsulated AgNPs, achieving enormous enhancement factor (~ 6.24 × 10 8 ). After undergoes mechanical deformation, the flexible SERS substrate still maintains high mechanical stability, which was proved by experiment and theory. For practical applications, the prepared flexible SERS substrate is adapted to the in-situ Raman detection of adenosine aqueous solution and the methylene-blue (MB) molecule detection of the skin of a fish, providing a direct and nondestructive active-platform for the detecting on the surfaces with any arbitrary morphology and aqueous solution.

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“…The analytical SERS Ef is the average increase in the scattering volume and is more reproducible. The analytical enhancement factor can then be defined as = (7) where an analyte solution with concentration CRS, produces a Raman signal IRS under non-SERS conditions on conventional Ag thin film. 44 The background-corrected peak height of the Rh6G peak at around 1364 cm −1 was used to measure the overall response to SERS.…”

Section: Sers Studies On Flexible Agns Substratesmentioning

confidence: 99%

Plasmonic Nanoslit Arrays Fabricated by Serial Bideposition: Optical and Surface-Enhanced Raman Scattering Study

Kumar

Doi

Namura

et al. 2020

ACS Appl. Bio Mater.

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Recently, studies have been carried out on attempts to combine surface-enhanced Surface-enhanced Raman spectroscopy (SERS) substrates that can be based on either localized surface plasmon (LSP) or surface plasmon polaritons (SPP) structures. By combining these two systems, the drawbacks of each other can be solved. However, the manufacturing methods involved so far are sophisticated, labor-intensive, expensive, and also technically demanding. We propose a facile method for the fabrication of a flexible plasmonic nanoslit SERS sensor. We utilized the pattern on periodic optical disks (DVD-R) as a cheap substitute for printing the periodic pattern on PDMS with soft imprint lithography. Ag nanoslit (AgNS) was fabricated by serial bideposition using a dynamic oblique angle deposition (DOD) technique. The nanoslit structures were physically and optically characterized, and the experimental results were compared to the numerical simulation studies; Monte Carlo and the finite-difference time-domain (FDTD) 2 simulation. The Ag nanoslit structure showed an excellent SERS enhancement, and its biosensing capability was demonstrated by the sensing of bilirubin. INTRODUCTIONSurface-enhanced Raman scattering (SERS) is an enormous Raman signal enhancement in the presence of nanoscale features such as rough surfaces, wedge, sharp tips, metallic nanostructure edges, cracks or other discontinuities that allow ultrasensitive detection at a single molecular level. 1-3 SERS offers a wide range of applications across different fields, including biological sensing, trace analysis, medical diagnostics, forensics, pesticide detection, explosives, and medicines. [4][5][6][7][8][9] There are different methods to manufacture SERS substrates which can either be based on localized surface plasmon resonance (LSPR) or surface plasmon polariton (SPP). [10][11][12] The LSPR wavelength is dependent on the refraction index of the medium and the geometric shape, size, and structure of the nanoparticle. The coupling of between LSPR of the adjacent nanoparticles can enhance the SERS intensity by several order of magnitude. 13,14 However, in practice it is difficult to control the precise orientation and separation of nanoparticle. LSP-based SERS substrates suffer from the disadvantage of a complicated manufacturing method and low signal reproducibility. 15,16 SPP-based SERS substrate, such as a metal grating, can generate a more uniform electric field but has the disadvantage of low SERS signal enhancement. 17,18 Currently, there are a few studies on attempts to merge LSP and SPP structures to compensate for each other's disadvantages. By combining these two structures, a higher electric field concentration and a better SERS improvement can be achieved. [18][19][20] Lithography, such as electron beam lithography, nanosphere lithography, or lithographic templates, is a well-known fabrication method for the generation of periodic plasmonic structure. Supporting InformationSchematic showing the construction of grooved polycarbonate DVD grating substrate ...

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A facile method for fabrication of buckled PDMS silver nanorod arrays as active 3D SERS cages for bacterial sensing

Cited by 79 publications

References 39 publications

Plasmonic bacteria on a nanoporous mirror via hydrodynamic trapping for rapid identification of waterborne pathogens

Plasmonic bacteria on a nanoporous mirror via hydrodynamic trapping for rapid identification of waterborne pathogens

3D Ultrasensitive Polymers-Plasmonic Hybrid Flexible Platform for In-Situ Detection

Plasmonic Nanoslit Arrays Fabricated by Serial Bideposition: Optical and Surface-Enhanced Raman Scattering Study

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