scholarly journals Nanostructured Plasma Polymerized Fluorocarbon Films for Drop Coating Deposition Raman Spectroscopy (DCDRS) of Liposomes

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4023
Author(s):  
Alžbeta Kuižová ◽  
Anna Kuzminova ◽  
Ondřej Kylián ◽  
Eva Kočišová
Keyword(s):  
Contact Angle ◽  
Raman Spectroscopy ◽  
Magnetron Sputtering ◽  
Polymer Surfaces ◽  
Raman Signal ◽  
Coating Deposition ◽  
Fluorocarbon Films ◽  
Wetting Properties ◽  
Liquid Samples ◽  
Weak Intensity

Raman spectroscopy is one of the most used biodetection techniques. However, its usability is hampered in the case of low concentrated substances because of the weak intensity of the Raman signal. To overcome this limitation, the use of drop coating deposition Raman spectroscopy (DCDRS), in which the liquid samples are allowed to dry into well-defined patterns where the non-volatile solutes are highly concentrated, is appropriate. This significantly improves the Raman sensitivity when compared to the conventional Raman signal from solution/suspension. As DCDRS performance strongly depends on the wetting properties of substrates, we demonstrate here that the smooth hydrophobic plasma polymerized fluorocarbon films prepared by magnetron sputtering (contact angle 108°) are well-suited for the DCDRS detection of liposomes. Furthermore, it was proved that even better improvement of the Raman signal might be achieved if the plasma polymer surfaces are roughened. In this case, 100% higher intensities of Raman signal are observed in comparison with smooth fluorocarbon films. As it is shown, this effect, which has no influence on the profile of Raman spectra, is connected with the increased hydrophobicity of nanostructured fluorocarbon films. This results in the formation of dried liposomal deposits with smaller diameters and higher preconcentration of liposomes.

Deposition of Fluorocarbon Thin Films on Polypropylene Substrate by RF Magnetron Sputtering

2009 ◽  
Vol 79-82 ◽  
pp. 875-878 ◽  
Author(s):  
Yu Hui Zhang ◽  
Quan Ji ◽  
Wen Fei Chen
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Growth Pattern ◽  
Rf Magnetron Sputtering ◽  
Discharge Power ◽  
Growth Mode ◽  
One Dimensional ◽  
Fluorocarbon Films

Radio frequency (rf) magnetron sputtering of polytetrafluoroethylene (PTFE) using argon as the working gas was used to prepare hydrophobic fluorocarbon films on a polypropylene substrate. The morphology, structure and hydrophobicity of the fluorocarbon films were analyzed by means of SEM, AFM, XPS and contact angle determination. The growth pattern in this system was a typical one-dimensional (1-D) Volmer-Weber growth mode. The films demonstrated dependence of structure and hydrophobicity on the conditions of preparation. The contact angle decreased with increasing discharge power and increased with increasing pressure. Those trends are attributed to the presence of differing proportions of -CF3, -CF2-, -CF-, and -C- in fluorocarbon thin films prepared with different energy.

scholarly journals Rapid uropathogen identification using surface enhanced Raman spectroscopy active filters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simon D. Dryden ◽  
Salzitsa Anastasova ◽  
Giovanni Satta ◽  
Alex J. Thompson ◽  
Daniel R. Leff ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Surface Enhanced Raman Spectroscopy ◽  
Active Filters ◽  
Raman Signal ◽  
Rapid Diagnostics ◽  
Bacterial Classification ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

AbstractUrinary tract infection is one of the most common bacterial infections leading to increased morbidity, mortality and societal costs. Current diagnostics exacerbate this problem due to an inability to provide timely pathogen identification. Surface enhanced Raman spectroscopy (SERS) has the potential to overcome these issues by providing immediate bacterial classification. To date, achieving accurate classification has required technically complicated processes to capture pathogens, which has precluded the integration of SERS into rapid diagnostics. This work demonstrates that gold-coated membrane filters capture and aggregate bacteria, separating them from urine, while also providing Raman signal enhancement. An optimal gold coating thickness of 50 nm was demonstrated, and the diagnostic performance of the SERS-active filters was assessed using phantom urine infection samples at clinically relevant concentrations (105 CFU/ml). Infected and uninfected (control) samples were identified with an accuracy of 91.1%. Amongst infected samples only, classification of three bacteria (Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae) was achieved at a rate of 91.6%.

The state of coating–substrate interfacial region formed during TiO2 coating deposition by Gas Injection Magnetron Sputtering technique

2020 ◽  
Vol 398 ◽  
pp. 126092 ◽  
Author(s):  
Rafal Chodun ◽  
Katarzyna Nowakowska-Langier ◽  
Bartosz Wicher ◽  
Sebastian Okrasa ◽  
Roch Kwiatkowski ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Gas Injection ◽  
The State ◽  
Tio2 Coating ◽  
Interfacial Region ◽  
Coating Deposition

scholarly journals Fabrication-friendly polarization-sensitive plasmonic grating for optimal surface-enhanced Raman spectroscopy

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Arpan Dutta ◽  
Tarmo Nuutinen ◽  
Khairul Alam ◽  
Antti Matikainen ◽  
Peng Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fill Factor ◽  
Surface Enhanced Raman Spectroscopy ◽  
Transverse Magnetic ◽  
Raman Signal ◽  
Optical Resonance ◽  
Excitation Light ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Plasmonic Gratings

Abstract Plasmonic nanostructures are widely utilized in surface-enhanced Raman spectroscopy (SERS) from ultraviolet to near-infrared applications. Periodic nanoplasmonic systems such as plasmonic gratings are of great interest as SERS-active substrates due to their strong polarization dependence and ease of fabrication. In this work, we modelled a silver grating that manifests a subradiant plasmonic resonance as a dip in its reflectivity with significant near-field enhancement only for transverse-magnetic (TM) polarization of light. We investigated the role of its fill factor, commonly defined as a ratio between the width of the grating groove and the grating period, on the SERS enhancement. We designed multiple gratings having different fill factors using finite-difference time-domain (FDTD) simulations to incorporate different degrees of spectral detunings in their reflection dips from our Raman excitation (488 nm). Our numerical studies suggested that by tuning the spectral position of the optical resonance of the grating, via modifying their fill factor, we could optimize the achievable SERS enhancement. Moreover, by changing the polarization of the excitation light from transverse-magnetic to transverse-electric, we can disable the optical resonance of the gratings resulting in negligible SERS performance. To verify this, we fabricated and optically characterized the modelled gratings and ensured the presence of the desired detunings in their optical responses. Our Raman analysis on riboflavin confirmed that the higher overlap between the grating resonance and the intended Raman excitation yields stronger Raman enhancement only for TM polarized light. Our findings provide insight on the development of fabrication-friendly plasmonic gratings for optimal intensification of the Raman signal with an extra degree of control through the polarization of the excitation light. This feature enables studying Raman signal of exactly the same molecules with and without electromagnetic SERS enhancements, just by changing the polarization of the excitation, and thereby permits detailed studies on the selection rules and the chemical enhancements possibly involved in SERS.

Preparation and the Blood Compatibility of Titanium Oxide Nanorod Arrays

2011 ◽  
Vol 306-307 ◽  
pp. 25-30 ◽  
Author(s):  
Ping Luo ◽  
Zhan Yun Huang ◽  
Di Hu Chen
Keyword(s):  
Contact Angle ◽  
Surface Morphology ◽  
Titanium Oxide ◽  
Tin Oxide ◽  
Growth Parameters ◽  
Blood Compatibility ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Nanorod Arrays ◽  
Wetting Properties

In this work, titanium oxide nanorod arrays were fabricated by using the hydrothermal method on fluorine-doped tin oxide (FTO) coated glass. The diameter of the nanorods could be controlled from 150 nm to 30 nm by changing the growth parameters. The surface morphology and the structure of the samples were characterized by SEM and XRD. The wetting properties were identified by contact angle measurement. Platelet attachment was investigated to evaluate the blood compatibility of the samples with different nanoscale topographies. Results show that the nanotopographical surfaces perform outstanding blood compatibility, and the adhering platelet decreased with the increasing diameter of the nanorods.

TiO2/SiO2 multilayer as an antireflective and protective coating deposited by microwave assisted magnetron sputtering

2013 ◽  
Vol 21 (2) ◽  
Author(s):  
M. Mazur ◽  
D. Wojcieszak ◽  
J. Domaradzki ◽  
D. Kaczmarek ◽  
S. Song ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
High Vacuum ◽  
Visible Spectrum ◽  
Ultra High Vacuum ◽  
Protective Film ◽  
Wetting Properties ◽  
Microwave Assisted ◽  
Atomic Force ◽  
Packed Structure ◽  
Protective Performance

AbstractIn this paper designing, preparation and characterization of multifunctional coatings based on TiO2/SiO2 has been described. TiO2 was used as a high index material, whereas SiO2 was used as a low index material. Multilayers were deposited on microscope slide substrates by microwave assisted reactive magnetron sputtering process. Multilayer design was optimized for residual reflection of about 3% in visible spectrum (450–800 nm). As a top layer, TiO2 with a fixed thickness of 10 nm as a protective film was deposited. Based on transmittance and reflectance spectra, refractive indexes of TiO2 and SiO2 single layers were calculated. Ultra high vacuum atomic force microscope was used to characterize the surface properties of TiO2/SiO2 multilayer. Surface morphology revealed densely packed structure with grains of about 30 nm in size. Prepared samples were also investigated by nanoindentation to evaluate their protective performance against external hazards. Therefore, the hardness of the thin films was measured and it was equal to 9.34 GPa. Additionally, contact angle of prepared coatings has been measured to assess the wetting properties of the multilayer surface.

scholarly journals Laser Raman Spectroscopy with Different Excitation Sources and Extension to Surface Enhanced Raman Spectroscopy

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Md. Wahadoszamen ◽  
Arifur Rahaman ◽  
Nabil Md. Rakinul Hoque ◽  
Aminul I Talukder ◽  
Kazi Monowar Abedin ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Silver Nanoparticles ◽  
Rhodamine 6G ◽  
Detection Efficiency ◽  
Colloidal Suspension ◽  
Surface Enhanced Raman Spectroscopy ◽  
Laser Raman Spectroscopy ◽  
Raman Signal ◽  
Fluorescence Signal ◽  
Present System

A dispersive Raman spectrometer was used with three different excitation sources (Argon-ion, He-Ne, and Diode lasers operating at 514.5 nm, 633 nm, and 782 nm, resp.). The system was employed to a variety of Raman active compounds. Many of the compounds exhibit very strong fluorescence while being excited with a laser emitting at UV-VIS region, hereby imposing severe limitation to the detection efficiency of the particular Raman system. The Raman system with variable excitation laser sources provided us with a desired flexibility toward the suppression of unwanted fluorescence signal. With this Raman system, we could detect and specify the different vibrational modes of various hazardous organic compounds and some typical dyes (both fluorescent and nonfluorescent). We then compared those results with the ones reported in literature and found the deviation within the range of ±2 cm−1, which indicates reasonable accuracy and usability of the Raman system. Then, the surface enhancement technique of Raman spectrum was employed to the present system. To this end, we used chemically prepared colloidal suspension of silver nanoparticles as substrate and Rhodamine 6G as probe. We could observe significant enhancement of Raman signal from Rhodamine 6G using the colloidal solution of silver nanoparticles the average magnitude of which is estimated to be 103.

The Surface Modification with Fluorocarbon Thin Films for the Prevention of Stiction in Mems

1998 ◽  
Vol 518 ◽  
Author(s):  
Sang-Ho Lee ◽  
Myong-Jong Kwon ◽  
Jin-Goo Park ◽  
Yong-Kweon Kim ◽  
Hyung-Jae Shin
Keyword(s):  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Fluorocarbon Films ◽  
Perfluorodecanoic Acid ◽  
Large Hysteresis ◽  
Static Contact ◽  
Receding Contact ◽  
Highly Hydrophobic ◽  
Receding Contact Angle

AbstractHighly hydrophobic fluorocarbon films were prepared by the vapor phase (VP) deposition method in a vacuum chamber using both liquid (3M's FC40, FC722) and solid sources (perfluorodecanoic acid (CF3(CF2)8COOH), perfluorododecane (C12F26)) on Al, Si and oxide coated wafers. The highest static contact angles of water were measured on films deposited on aluminum substrate. But relatively lower contact angles were obtained on the films on Si and oxide wafers. The advancing and receding contact angle analysis using a captive drop method showed a large contact angle hysteresis (ΔH) on the VP deposited fluorocarbon films. AFM study showed poor film coverage on the surface with large hysteresis. FTIR-ATR analysis positively revealed the stretching band of CF2 groups on the VP deposited substrates. The thermal stability of films was measured at 150°C in air and nitrogen atmospheres as a function of time. The rapid decrease of contact angles was observed on VP deposited FC and PFDA films in air. However, no decrease of contact angle on them was observed in N2.

Drop-coating deposition Raman spectroscopy of liposomes

2011 ◽  
Vol 42 (8) ◽  
pp. 1606-1610 ◽  
Author(s):  
Eva Kočišová ◽  
Marek Procházka
Keyword(s):  
Raman Spectroscopy ◽  
Coating Deposition

Raman Spectroscopy for the Study of XVI-XVII Centuries Colonial Paintings

2014 ◽  
Vol 1618 ◽  
pp. 141-151 ◽  
Author(s):  
Ma. A. García-Bucio ◽  
E. Casanova-González ◽  
J. L. Ruvalcaba-Sil
Keyword(s):  
Raman Spectroscopy ◽  
San Francisco ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Surface Enhanced Raman Spectroscopy ◽  
Raman Signal ◽  
Invasive Approach ◽  
Full Characterization ◽  
Surface Enhanced Raman ◽  
Historical Objects

ABSTRACTOutstanding information about the material composition and pictorial techniques of the New Spain Colonial painting can be obtained via a full characterization using a set of analytical techniques. Given the cultural importance of this painting, a non-invasive approach is preferred. Moreover, the preparation and use of reference materials using original recipes is necessary for a correct interpretation of the spectroscopic data from historical objects. Here, we present the results obtained via an in-situ Raman spectroscopic analysis of a set of pictorial reference materials, created according to XVI and XVII centuries’ recipes. Several difficulties were encountered, such as the low Raman detection signal, an intrinsic fluorescence of the material, and in some cases even laser-induced degradation. For this reason, the usual molecular Raman analysis was extended to Surface Enhanced Raman Spectroscopy (SERS), which enhances the Raman signal and quenches the fluorescence. It was then applied to the analysis of two wood paintings from the ex-convent San Francisco Tepeyanco, in Tlaxcala.

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