scholarly journals Fabrication of arrayed triangular micro-cavities for SERS substrates using the force modulated indention process

RSC Advances ◽  
2017 ◽  
Vol 7 (20) ◽  
pp. 11969-11978 ◽  
Author(s):  
Yongda Yan ◽  
Jingran Zhang ◽  
Ping Xu ◽  
Peng Miao

Based on the tip-based continuous indentation process, a novel method for the fabrication of periodic arrayed triangular micro-cavities on copper (Cu) surface is presented as SERS substrates.

2017 ◽  
Vol 8 ◽  
pp. 2271-2282 ◽  
Author(s):  
Jingran Zhang ◽  
Yongda Yan ◽  
Peng Miao ◽  
Jianxiong Cai

Using the tip-based continuous indentation process, arrays of three-dimensional pyramidal cavities have been successfully machined on a copper template and the structures were successfully transferred to a polydimethylsiloxane (PDMS) surface using a reverse nanoimprinting approach. The structured PDMS surface is coated with a thin Au film, and the final substrate is demonstrated as a surface-enhanced Raman spectroscopy (SERS) substrate. Rhodamine 6G (R6G) was used as a probe molecule in the present study to confirm the SERS measurements. Arrays of micro/nanostructures of different dimensions were formed by the overlap of pyramidal cavities with different adjacent distances using the tip-based continuous indentation process. The effects of the reverse nanoimprinting process and coating process on the final topography of the structures are studied. The experimental results show that the Raman intensity of the Au-film-coated PDMS substrate is influenced by the topography of the micro/nanostructures and by the thickness of the Au film. The Raman intensity of 1362 cm−1 R6G peak on the structured Au-film-coated PDMS substrate is about 8 times higher than the SERS tests on a commercial substrate (Q-SERS). A SERS enhancement factor ranging from 7.5 × 105 to 6 × 106 was achieved using the structured Au-film-coated PDMS surface, and it was demonstrated that the method proposed in this paper is reliable, replicable, homogeneous and low-cost for the fabrication of SERS substrates.


2017 ◽  
Vol 53 (37) ◽  
pp. 5121-5124 ◽  
Author(s):  
B. Fortuni ◽  
Y. Fujita ◽  
M. Ricci ◽  
T. Inose ◽  
R. Aubert ◽  
...  

A one-step method to form gold nanostars on a polydimethylsiloxane film is proposed for highly-sensitive SERS substrates.


2019 ◽  
Author(s):  
Jingran Zhang ◽  
Tianqi Jia ◽  
Yongda Yan ◽  
Li Wang ◽  
Peng Miao ◽  
...  

Nanostructures and nanoparticles are two typical structures which have already been widely employed as the Surface Enhanced Raman Scattering (SERS) substrates. In most studies, they are employed separately as SERS substrates. Recently, the hierarchical structures including nanostructures and nanoparticles present better SERS characteristics. However, how to machine such hierarchical structures is a big problem. In the present study, a novel method integrating the nanoindentation process and chemical redox reaction to machine the hierarchical SERS substrate is provided. Micro/nanostructures are formed on the Cu(110) plane first, and then Ag nanoparticles are generated on the structured Copper surface. Effects of parameters of the indentation process and the corrosion times in the AgNO3 solutions on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multi Ag nanoparticles on the surface of plane and micro/nanostructures are studied with the COMSOL software. The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor of malachite green molecules can reach to 5.089×109, which proves that the method is simple, replicable and low cost method for machining the hierarchical SERS substrate.


Author(s):  
M.A. Gregory ◽  
G.P. Hadley

The insertion of implanted venous access systems for children undergoing prolonged courses of chemotherapy has become a common procedure in pediatric surgical oncology. While not permanently implanted, the devices are expected to remain functional until cure of the primary disease is assured. Despite careful patient selection and standardised insertion and access techniques, some devices fail. The most commonly encountered problems are colonisation of the device with bacteria and catheter occlusion. Both of these difficulties relate to the development of a biofilm within the port and catheter. The morphology and evolution of biofilms in indwelling vascular catheters is the subject of ongoing investigation. To date, however, such investigations have been confined to the examination of fragments of biofilm scraped or sonicated from sections of catheter. This report describes a novel method for the extraction of intact biofilms from indwelling catheters.15 children with Wilm’s tumour and who had received venous implants were studied. Catheters were removed because of infection (n=6) or electively at the end of chemotherapy.


GeroPsych ◽  
2012 ◽  
Vol 25 (4) ◽  
pp. 235-245 ◽  
Author(s):  
Katja Franke ◽  
Christian Gaser

We recently proposed a novel method that aggregates the multidimensional aging pattern across the brain to a single value. This method proved to provide stable and reliable estimates of brain aging – even across different scanners. While investigating longitudinal changes in BrainAGE in about 400 elderly subjects, we discovered that patients with Alzheimer’s disease and subjects who had converted to AD within 3 years showed accelerated brain atrophy by +6 years at baseline. An additional increase in BrainAGE accumulated to a score of about +9 years during follow-up. Accelerated brain aging was related to prospective cognitive decline and disease severity. In conclusion, the BrainAGE framework indicates discrepancies in brain aging and could thus serve as an indicator for cognitive functioning in the future.


2014 ◽  
Vol 62 (S 02) ◽  
Author(s):  
J. Photiadis ◽  
M. Musci ◽  
O. Miera ◽  
S. Ovroutski ◽  
A. Mekkawy ◽  
...  

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