Handheld Raman Spectrometer Instrumentation for Quantitative Tuberculosis Biomarker Detection: A Performance Assessment for Point-of-Need Infectious Disease Diagnostics

2018 ◽  
Vol 72 (7) ◽  
pp. 1104-1115 ◽  
Author(s):  
Nicholas A. Owens ◽  
Lars B. Laurentius ◽  
Marc D. Porter ◽  
Qun Li ◽  
Sean Wang ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Integration Time ◽  
Excitation Wavelength ◽  
Disease Biomarkers ◽  
Raman Spectrometer ◽  
Level Measurement ◽  
Disease Diagnostics ◽  
Infectious Disease Diagnostics ◽  
Surface Enhanced Raman ◽  
Sers Detection

Techniques for the detection of disease biomarkers are key components in the protection of human health. While work over the last few decades has redefined the low-level measurement of disease biomarkers, the translation of these capabilities from the formal clinical setting to point-of-need (PON) usage has been much more limited. This paper presents the results of experiments designed to examine the potential utility of a handheld Raman spectrometer as a PON electronic reader for a sandwich immunoassay based on surface-enhanced Raman scattering (SERS). In so doing, the study herein used a recently developed procedure for the SERS detection of phospho-myo-inositol-capped lipoarabinomannan (PILAM) as a means to compare the performance of laboratory-grade and handheld instrumentation and, therefore, gauge the utility of the handheld instrument for PON deployment. Phospho-myo-inositol-capped lipoarabinomannan is a non-pathogenic simulant for mannose-capped lipoarabinomannan (ManLAM), which is an antigenic marker found in serum and other body fluids of individuals infected with tuberculosis (TB). The results of the measurements with the field-portable spectrometer were then compared to those obtained for the same samples when using a much more sensitive benchtop Raman spectrometer. The results, albeit under different operational settings for the two spectrometers (e.g., signal integration time), are promising in that the limit of detection found for PILAM spiked in human serum when using the handheld system (0.18 ng/mL) approached that of the benchtop instrument (0.032 ng/mL). This work also: (1) identified potential adaptations (e.g., optimization of the plasmonically enhanced response for measurement by the handheld unit through a change in the excitation wavelength) to tighten the gap in performance; and (2) briefly examined the next steps and potential processes required to move this immunoassay platform closer to PON utility.

scholarly journals Application of Aluminum Hydroxide for Improvement of Label-Free SERS Detection of Some Cephalosporin Antibiotics in Urine

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 91 ◽  
Author(s):  
Natalia E. Markina ◽  
Alexey V. Markin
Keyword(s):  
Aluminum Hydroxide ◽  
Surface Enhanced Raman Spectroscopy ◽  
Negative Influence ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Excitation Wavelength ◽  
Sers Substrate ◽  
Label Free ◽  
Surface Enhanced Raman ◽  
Sers Detection

This report is dedicated to development of surface-enhanced Raman spectroscopy (SERS) based analysis protocol for detection of antibiotics in urine. The key step of the protocol is the pretreatment of urine before the detection to minimize background signal. The pretreatment includes extraction of intrinsic urine components using aluminum hydroxide gel (AHG) and further pH adjusting of the purified sample. The protocol was tested by detection of a single antibiotic in artificially spiked samples of real urine. Five antibiotics of cephalosporin class (cefazolin, cefoperazone, cefotaxime, ceftriaxone, and cefuroxime) were used for testing. SERS measurements were performed using a portable Raman spectrometer with 638 nm excitation wavelength and silver nanoparticles as SERS substrate. The calibration curves of four antibiotics (cefuroxime is the exception) cover the concentrations required for detection in patient’s urine during therapy (25/100‒500 μg/mL). Random error of the analysis (RSD < 20%) and limits of quantification (20‒90 μg/mL) for these antibiotics demonstrate the applicability of the protocol for reliable quantitative detection during therapeutic drug monitoring. The detection of cefuroxime using the protocol is not sensitive enough, allowing only for qualitative detection. Additionally, time stability and batch-to-batch reproducibility of AHG were studied and negative influence of the pretreatment protocol and its limitations were estimated and discussed.

scholarly journals Preparation of Hydrophobic Film by Electrospinning for Rapid SERS Detection of Trace Triazophos

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4120
Author(s):  
Fei Shao ◽  
Jiaying Cao ◽  
Ye Ying ◽  
Ying Liu ◽  
Dan Wang ◽  
...  
Keyword(s):  
Hot Spots ◽  
Large Scale ◽  
Limit Of Detection ◽  
Small Region ◽  
Sers Substrate ◽  
Ag Nps ◽  
Electrospinning Technique ◽  
Heterocyclic Molecules ◽  
Surface Enhanced Raman ◽  
Sers Detection

For real application, it is an urgent demand to fabricate stable and flexible surface-enhanced Raman scattering (SERS) substrates with high enhancement factors in a large-scale and facile way. Herein, by using the electrospinning technique, a hydrophobic and flexible poly(styrene-co-butadiene) (SB) fibrous membrane is obtained, which is beneficial for modification of silver nanoparticles (Ag NPs) colloid in a small region and then formation of more “hot spots” by drying; the final SERS substrate is designated as Ag/SB. Hydrophobic Ag/SB can efficiently capture heterocyclic molecules into the vicinity of hot spots of Ag NPs. Such Ag/SB films are used to quantitatively detect trace triazophos residue on fruit peels or in the juice, and the limit of detection (LOD) of 2.5 × 10−8 M is achieved. Ag/SB films possess a capability to resist heat. As a case, 6-mercaptopurine (6MP) that just barely dissolves in 90 °C water is picked for conducting Ag/SB-film-based experiments.

scholarly journals A Simple Route for the Preparation of Gold Nanofilms and Their Application in SERS Detection of Pyrene in Water

2022 ◽  
Vol 2160 (1) ◽  
pp. 012030
Author(s):  
Huan Zhang ◽  
Cuipin Wang ◽  
Shan Wang ◽  
Chunrong Wang
Keyword(s):  
Limit Of Detection ◽  
Tap Water ◽  
Chromatography Method ◽  
Analysis Process ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Polycyclic Aromatic ◽  
Potential Alternative ◽  
Enhanced Raman Scattering ◽  
Promising Solution

Abstract Design and preparation of various rational gold nanostructures has been recognized as a promising solution for the surface-enhanced Raman scattering (SERS) signal amplification. Here, a simple fabrication method was reported for the synthesis of highly sensitive gold nanofilms for SERS detection through covering ginger-liked gold nanoparticles on the stainless steel sheet. The prepared gold nanofilms were then tested by a dip-SPME-SERS method for detecting pyrene. The limit of detection for pyrene standard solution was 0.1ppb, while the limit of detection for pyrene in tap water and lake water without any pretreatment was 5 ppb, respectively. The whole analysis process takes less than 15 minutes. Our method may be a potential alternative way to the chromatography method. The fabricated gold nanfilms are expected to be used for the rapid and sensitive detection of other pollutants such as organic pesticides and polycyclic aromatic hydrocarbon.

scholarly journals Flexible and Reusable Ag Coated TiO2 Nanotube Arrays for Highly Sensitive SERS Detection of Formaldehyde

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1199 ◽  
Author(s):  
Tong Zhu ◽  
Hang Wang ◽  
Libin Zang ◽  
Sila Jin ◽  
Shuang Guo ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Catalytic Performance ◽  
Tio2 Nanotube ◽  
Detection Sensitivity ◽  
Sers Substrate ◽  
Environmental Media ◽  
Sensing Platform ◽  
Surface Enhanced Raman ◽  
Sers Detection

Quantitative analysis of formaldehyde (HCHO, FA), especially at low levels, in various environmental media is of great importance for assessing related environmental and human health risks. A highly efficient and convenient FA detection method based on surface-enhanced Raman spectroscopy (SERS) technology has been developed. This SERS-based method employs a reusable and soft silver-coated TiO2 nanotube array (TNA) material, such as an SERS substrate, which can be used as both a sensing platform and a degradation platform. The Ag-coated TNA exhibits superior detection sensitivity with high reproducibility and stability compared with other SERS substrates. The detection of FA is achieved using the well-known redox reaction of FA with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT) at room temperature. The limit of detection (LOD) for FA is 1.21 × 10−7 M. In addition, the stable catalytic performance of the array allows the degradation and cleaning of the AHMT-FA products adsorbed on the array surface under ultraviolet irradiation, making this material recyclable. This SERS platform displays a real-time monitoring platform that combines the detection and degradation of FA.

scholarly journals An integrated approach for trace detection of pollutants in water using polyelectrolyte functionalized magneto-plasmonic nanosorbents

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Paula C. Pinheiro ◽  
Sara Fateixa ◽  
Ana L. Daniel-da-Silva ◽  
Tito Trindade
Keyword(s):  
Limit Of Detection ◽  
Integrated Approach ◽  
Trace Detection ◽  
Monitoring Methods ◽  
Operational Parameters ◽  
Solution Ph ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Conventional Antibiotics ◽  
Micro Organisms

AbstractResistance of pathogenic micro-organisms to conventional antibiotics is an essential issue for public health. The presence of such pharmaceuticals in aquatic ecosystems has been of major concern for which remediation and ultra-sensitive monitoring methods have been proposed. A less explored strategy involves the application of multifunctional nanosorbents for the uptake and subsequent detection of vestigial contaminants. In this study, colloidal nanoparticles (NPs) of iron oxide and gold were encapsulated in multi-layers of a charged polyelectrolyte (PEI: polyethyleneimine), envisaging the effective capture of tetracycline (TC) and its subsequent detection by Surface Enhanced Raman Scattering (SERS). Adsorption studies were performed by varying operational parameters, such as the solution pH and contact time, in order to evaluate the performance of the nanosorbents for the uptake of TC from water. While the magnetic nanosorbents with an external PEI layer (Fe3O4@PEI and Fe3O4@PEI-Au@PEI particles) have shown better uptake efficiency for TC, these materials showed less SERS sensitivity than the Fe3O4@PEI- Au nanosorbents, whose SERS sensitivity for TC in water has reached the limit of detection of 10 nM. Thus, this study highlights the potential of such magneto-plasmonic nanosorbents as multi-functional platforms for targeting specific contaminants in water, by taking into consideration both functionalities investigated: the removal by adsorption and the SERS detection across the nanosorbents’ surfaces.

scholarly journals Surface Enhanced Raman Spectroscopy Detection of Sodium Thiocyanate in Milk Based on the Aggregation of Ag Nanoparticles

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1363 ◽  
Author(s):  
Yanting Feng ◽  
Rijian Mo ◽  
Ling Wang ◽  
Chunxia Zhou ◽  
Pengzhi Hong ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Trichloroacetic Acid ◽  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sodium Thiocyanate ◽  
Ag Nps ◽  
Trichloroacetic Acid Solution ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Detection

A method is developed for detecting the concentration of sodium thiocyanate (NaSCN) in milk based on surface-enhanced Raman scattering (SERS) technology. A trichloroacetic acid solution can be used to enhance the SERS signal because of its function in promoting the aggregation of Ag nanoparticles (Ag NPs). Meanwhile, the protein in milk would be precipitated as trichloroacetic acid added and the interference from protein could be reduced during the detection. In this work, the enhancement factor (EF) is 7. 56 × 105 for sodium thiocyanate in water and the limit of detection (LOD) is 0.002 mg/L. Meanwhile, this method can be used to detect the concentration of sodium thiocyanate in milk. Results show that SERS intensity increased as the concentration of sodium thiocyanate increase from 10 to 100 mg/L. The linear correlation coefficient is R2 = 0.998 and the detection limit is 0.04 mg/L. It is observed that the concentration of sodium thiocyanate does not exceed the standard in the three kinds of milk. The confirmed credibility of SERS detection is compared with conventional methods.

scholarly journals Sensitive SERS nanotags for use with a hand-held 1064 nm Raman spectrometer

2017 ◽  
Vol 4 (7) ◽  
pp. 170422 ◽  
Author(s):  
Hayleigh Kearns ◽  
Fatima Ali ◽  
Matthew A. Bedics ◽  
Neil C. Shand ◽  
Karen Faulds ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Detection Limits ◽  
Short Wave ◽  
Electromagnetic Spectrum ◽  
Portable Instrument ◽  
Raman Spectrometer ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Enhanced Raman Scattering

This is the first report of the use of a hand-held 1064 nm Raman spectrometer combined with red-shifted surface-enhanced Raman scattering (SERS) nanotags to provide an unprecedented performance in the short-wave infrared (SWIR) region. A library consisting of 17 chalcogenopyrylium nanotags produce extraordinary SERS responses with femtomolar detection limits being obtained using the portable instrument. This is well beyond previous SERS detection limits at this far red-shifted wavelength and opens up new options for SERS sensors in the SWIR region of the electromagnetic spectrum (between 950 and 1700 nm).

Study on Detection of Carbaryl Pesticides by Using Surface-Enhance Raman Spectroscopy

2020 ◽  
Vol 853 ◽  
pp. 97-101
Author(s):  
Chaiwat Chakaja ◽  
Saksorn Limwichean ◽  
Noppadon Nuntawong ◽  
Pitak Eiamchai ◽  
Sukon Kalasung ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Exposure Time ◽  
Laser Power ◽  
Limit Of Detection ◽  
Surface Enhance Raman Spectroscopy ◽  
Raman Spectrometer ◽  
Surface Enhanced Raman ◽  
Solid Form ◽  
Portable Raman

In this research, the Ag nanorod structure was used as surface enhanced Raman scattering (SERS) chip which provides a sensitive detection signal for trace analysis of carbaryl pesticide. Carbaryl in solid form was measured by using the standard Raman spectroscopy to investigate the spectrum. Carbaryl at various concentrations was prepared in acetonitrile and dropped on the SERS chip for measuring Raman spectrum by a portable Raman spectrometer. The measurement condition including laser power and exposure time were studied to test the performance of SERS chip for carbaryl detection. From the results, the SERS chip useful for enhancing the Raman scattering signal which was increased depending on the laser power and exposure time. Carbaryl can be detected on SERS chip couple with the portable Raman spectrometer with the limit of detection of 10-5 M.

Rapid Detection of Cypermethrin by Using Surface-Enhanced Raman Scattering Technique

2020 ◽  
Vol 853 ◽  
pp. 102-106
Author(s):  
Wipawanee Leung ◽  
Saksorn Limwichean ◽  
Noppadon Nuntawong ◽  
Pitak Eiamchai ◽  
Sukon Kalasung ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Rapid Detection ◽  
Limit Of Detection ◽  
Surface Enhanced Raman Scattering ◽  
Sers Substrate ◽  
Silver Nanorods ◽  
Raman Spectrometer ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Cypermethrin is a toxic pesticide in the pyrethroid group. A Surface Enhanced Raman Scattering (SERS) based sensor has been developed to achieve simple pesticide sensing. In this work, rapid detection of cypermethrin by using the handheld Raman spectroscopy coupled with SERS substrate was demonstrated. SERS-active silver nanorods substrate was used to enhance Raman signals of test samples. The effect of exposure time and drop volume of sample was studied for cypermethrin measurement. The results found that the silver nanorods substrate can be used to measure cypermethrin in the range of 10-6 to 10-3 M with a handheld Raman spectrometer. Furthermore, the Raman signal of cypermethrin was confirmed by measuring solid cypermethrin with the standard Raman spectrometer. SERS substrate was competent to detect cypermethrin with a limit of detection (LOD) of 10-6 M.

scholarly journals Time-domain signal averaging to improve microparticles detection and enumeration accuracy in a microfluidic impedance cytometer

2021 ◽  
Author(s):  
Brandon Ashley ◽  
Umer Hassan
Keyword(s):  
Background Noise ◽  
Biomedical Applications ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Detection Limits ◽  
Signal Averaging ◽  
Average Technique ◽  
Disease Diagnostics ◽  
Infectious Disease Diagnostics ◽  
Impedance Cytometry

Microfluidic impedance cytometry is a powerful system to measure micro and nano-sized particles and is routinely used in point-of-care settings disease diagnostics and other biomedical applications. However, small objects near a sensor’s detection limit are plagued with relatively significant background noise and are difficult to identify for every case. While many data processing techniques can be utilized to reduce noise and improve signal quality, frequently they are still inadequate to push sensor detection limits. Here, we report the first demonstration of a novel signal averaging algorithm effective in noise reduction of microfluidic impedance cytometry data, improving enumeration accuracy and reducing detection limits. Our device uses a 22 μm tall microchannel and gold coplanar microelectrodes that generates an electric field, recording bipolar pulses from polystyrene microparticles flowing through the channel. In addition to outlining a modified moving signal averaging technique theoretically and with a model dataset, we also performed a compendium of characterization experiments including variations in flow rate, input voltage, and particle size. Multi-variate metrics from each experiment are compared including signal amplitude, pulse width, background noise, and signal-to-noise ratio (SNR). Incorporating our technique resulted in improved SNR and counting accuracy across all experiments conducted, and the limit of detection improved from 5 μm to 1 μm particles without modifying microchannel dimensions. Succeeding this, we envision implementing our modified moving average technique to develop next generation microfluidic impedance cytometry devices with an expanded dynamic range and improved enumeration accuracy. This can be exceedingly useful for many biomedical applications, such as infectious disease diagnostics where devices may enumerate larger-scale immune cells alongside sub-micron bacterium in the same sample.

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