scholarly journals 2D Dielectric Nanoimprinted PMMA Pillars on Metallo-Dielectric Films

2019 ◽  
Vol 9 (18) ◽  
pp. 3812 ◽  
Author(s):  
Stomeo ◽  
Casolino ◽  
Guido ◽  
Qualtieri ◽  
Scalora ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Ad Hoc ◽  
Surface Enhanced Raman Spectroscopy ◽  
Dielectric Films ◽  
Sio2 Substrate ◽  
Optical Resonances ◽  
Reflected Light ◽  
Incident Plane ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

In this work, we propose an optimized nanoimprint protocol for the fabrication of a two-dimensional (2D) array of polymethyl-methacrylate (PMMA) nano-pillars deposited on different sputtered configurations (bilayer and multi-layer) of copper (Cu) and aluminum nitride (AlN) slabs supported by a silicon dioxide (SiO2) substrate. Both the Cu/AlN bilayer and multilayer thin films were deposited by a sputtering technique. The sub-micron PMMA pillars were realized by using nanoimprint lithography (NIL). In order to optimize the NIL process, several tests were performed by varying temperature and pressure, allowing us to achieve uniform and high-resolution pillars. The fabricated periodic array enabled the phase-matching of the incident plane wave exciting optical resonances. All the fabricated devices were then optically characterized by means of an ad hoc setup, where the reflected light from the sample was analyzed. The fabricated nano-pillars are mechanically stable, and they could be fully exploited for the realization of novel metallo-dielectric core/shell structures for sensing, surface-enhanced Raman spectroscopy, and light–matter interactions.

Nanostructured probes to enhance optical and vibrational spectroscopic imaging for biomedical applications

2017 ◽  
Author(s):  
Anil K. Kodali ◽  
Rohit Bhargava
Keyword(s):  
Raman Spectroscopy ◽  
Biomedical Applications ◽  
Spectroscopic Imaging ◽  
Surface Enhanced Raman Spectroscopy ◽  
Ultrasensitive Detection ◽  
Optical Resonances ◽  
Surface Enhanced ◽  
Different Types ◽  
Surface Enhanced Raman ◽  
Ir And Raman

This article describes the use of nanostructured probes to enhance optical and vibrational spectroscopic imaging for biomedical applications. Engineered probes and surfaces are promising tools for enhancing signals for ultrasensitive detection of diseases like carcinoma. Two methods of interest are surface-enhanced infrared absorption (SEIRA) spectroscopy and surface-enhanced Raman spectroscopy (SERS) for IR and Raman modalities, respectively. SERS and SEIRA can be broadly categorized under a common modality termed surface-enhanced vibrational spectroscopy. This article first reviews various breakthrough findings reported in SERS and SEIRA, along with different types ofsubstrates and contrast agents used in realizing the enhancement and theories proposed to explain these findings. It then considers the configurations of nano-LAMPs and presents example results demonstrating their optical resonances and tunability. Finally, it evaluates a few techniques for fabricating multilayered nanoparticles and highlights some issues with respect to fabrication.

scholarly journals Thrombin Assessment on Nanostructured Label-Free Aptamer-Based Sensors: A Mapping Investigation via Surface-Enhanced Raman Spectroscopy

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Elisa Scatena ◽  
Sara Pascale ◽  
Cristina Cairone ◽  
Filippo Fabbri ◽  
Costantino Del Gaudio
Keyword(s):  
Raman Spectroscopy ◽  
Ad Hoc ◽  
High Specificity ◽  
Surface Enhanced Raman Spectroscopy ◽  
Label Free ◽  
Rna Molecules ◽  
Specificity And Sensitivity ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Aptamer Sensor

Aptamers, synthetic single-stranded DNA or RNA molecules, can be regarded as a valuable improvement to develop novel ad hoc sensors to diagnose several clinical pathologies. Their intrinsic potential is related to the high specificity and sensitivity to the selected target biomarkers, being capable of detecting very low concentrations and thus allowing an early diagnosis of a possible disease. This kind of probe can be usefully integrated into a number of different devices in order to provide a reliable acquisition of the analyte and properly elaborate the related signal. The study presents the fabrication and characterization of a label-free aptamer sensor designed using a gold-coated silicon nanostructured substrate to map the target molecule by means of surface-enhanced Raman spectroscopy (SERS). As a proof, thrombin was used as a model at four different concentrations (i.e., 0.0873, 0.873, 8.73, and 87.3 nM). SERS mapping analysis was carried out considering each representative band of the aptamer-thrombin complex (centered at 822, 1140, and 1558 cm−1) and then combining them in order to acquire a comprehensive and unambiguous measure of the target. In both cases, a valuable correlation was evaluated, even if the first approach can suffer from some limitations in the third band related to lower definition of the characteristic peak compared to those in the other two bands.

Hybrid gold nanofinger SERS structure for sensing applications

2011 ◽  
Vol 1359 ◽  
Author(s):  
Ansoon Kim ◽  
Zhiyong Li
Keyword(s):  
Nanoimprint Lithography ◽  
Large Scale ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Surface Enhanced Raman Spectroscopy ◽  
Active Molecule ◽  
Manufacturing Method ◽  
Sensing Applications ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

ABSTRACTWe report here a novel hybrid nanostructure for ultra-sensitive sensing applications based on surface-enhanced Raman spectroscopy (SERS). We rationally engineered gold-coated polymer pillar structures, named as gold nanofingers, in analogy to the tweezers at nanoscale, for active molecule capture and detection using SERS technique. Using nanoimprint lithography, we have demonstrated a cost effective manufacturing method of making such hybrid structures over large scale and achieve reliable enhancement factor. In particular, we have demonstrated the sensing application of the nanofinger structures for melamine and chlropyrifos. The limit of detection (LOD) of melamine in water is found to be 10 nM (1.3 ppb), and LOD of chlropyrifos (a pesticide) is found to be 1 nM (0.35 ppb), which is below the EPA tolerance level of 0.1 ppm for chlropyrifos on citrus fruits.

scholarly journals Surface-Enhanced Raman Spectroscopy (SERS) Study Using Oblique Angle Deposition of Ag Using Different Substrates

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1581 ◽  
Author(s):  
Jaeyeong Lee ◽  
Kyungchan Min ◽  
Youngho Kim ◽  
Hak Ki Yu
Keyword(s):  
Raman Spectroscopy ◽  
High Surface ◽  
Surface Enhanced Raman Spectroscopy ◽  
Oblique Angle Deposition ◽  
Oblique Angle ◽  
Sio2 Substrate ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Ag Substrate ◽  
Angle Deposition

The oblique angle deposition of Ag with different deposition rates and substrates was studied for surface-enhanced Raman spectroscopy (SERS) efficiency. The deposition rate for the Ag substrate with maximum SERS efficiency was optimized to 2.4 Å/s. We also analyzed the morphology of Ag nanorods deposited at the same rate on various substrates and compared their SERS intensities. Ag deposited on SiO2, sapphire, and tungsten showed straight nanorods shape and showed relatively high SERS efficiency. However, Ag deposited on graphene or plasma-treated SiO2 substrate was slightly or more aggregated (due to high surface energy) and showed low SERS efficiency.

Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

2017 ◽  
Author(s):  
Caitlin S. DeJong ◽  
David I. Wang ◽  
Aleksandr Polyakov ◽  
Anita Rogacs ◽  
Steven J. Simske ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Direct Detection ◽  
Point Of Care ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Recent Emergence ◽  
Surface Enhanced ◽  
Volatile Organic ◽  
Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, and <i>Serratia marcescens</i>. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of <i>E. coli</i> in under 12 hrs, and detected <i>E. coli</i> from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 10<sup>3</sup> CFU/ml and 10<sup>4</sup> CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

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