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Paper Spray - Mass Spectrometry: Investigation of Sampling Devices for Illicit Drug Detection and QuantificationNguyen, Chau Bao 07 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Paper spray - mass spectrometry (PS-MS) has been developed as a rapid and direct ionization method for qualitative and quantitative analysis of complex samples at trace levels. In this work, different sampling devices for PS-MS were investigated to improve the assay’s simplicity and sensitivity over traditional approaches. In particular, chapter two characterizes an alternate paper substrate to enhance drug detection on surfaces like asphalt, cloth, concrete, aluminum, and glass. Analysis occurs on a single spray ticket coated with pressure-sensitive adhesive (PSA), also known as Post-it notes to detect and quantify drug residues. A PS-MS method utilizing PSA paper was developed to detect a mixture of ten drugs off of various surfaces to evaluate the qualitative and quantitative capabilities of the aforementioned substrate. After the method development on a conventional linear ion trap mass spectrometer, the assay was translated for use on a portable mass spectrometer to evaluate the suitability of the pressure-sensitive adhesive paper substrate in the field in chapter three. Chapter four introduces a sampling device combined with a snap-in solid-phase extraction (SPE) column. The new cartridge design not only inherits the functions from the first iteration SPE cartridge, including extraction and preconcentration from complex samples, but also exhibits greater flexibility in volume control and ease of use for on-site sample collection.
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Nanoplasmonic efficacy of gold triangular nanoprisms in measurement science: applications ranging from biomedical to forensic sciencesLiyanage, Thakshila 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Noble metal nanostructures display collective oscillation of the surface conduction electrons upon light irradiation as a form of localized surface plasmon resonance (LSPR) properties. Size, shape, and refractive index of the surrounding environment are the key features that control the LSPR properties. Surface passivating ligands on to the nanostructure can modify the charge density of nanostructures. Further, allow resonant wavelengths to match that of the incident light. This unique phenomenon called the “plasmoelectric effect.” According to the Drude model, red and blue shifts of LSPR peak of nanostructures are observed in the event of reducing and increasing charge density, respectively. However, herein, we report unusual LSPR properties of gold triangular nanoprisms (Au TNPs) upon functionalization with para-substituted thiophenols (X-Ph-SH, X = -NH2, -OCH3, -CH3, -H, -Cl, -CF3, and -NO2). Accordingly, we hypothesized that an appropriate energy level alignment between the Au Fermi energy and the HOMO or LUMO of ligands allows the delocalization of surface plasmon excitation at the hybrid inorganic-organic interface. Thus, provides a thermodynamically driven plasmoelectric effect. We further validated our hypothesis by calculating the HOMO and LUMO levels and work function changes of Au TNPs upon functionalization with para-substituted thiol. This reported unique finding then utilized to design ultrasensitive plasmonic substrate for biosensing of cancer microRNA in bladder cancer and cardiovascular diseases. In the discovery of early bladder cancer diagnosis platform, for the first time, we have been utilized to analyze the tumor suppressor microRNA for a more accurate diagnosis of BC.
Additionally, we have been advancing our sensing platform to mitigate the false positive and negative responses of the sensing platform using surface-enhanced fluorescence technique. This noninvasive, highly sensitive, highly specific, also does not have false positives techniques that provide the strong key to detect cancer at a very early stage, hence increase the cancer survival rate. Moreover, the electromagnetic field enhancement of Surface-Enhanced Raman Scattering (SERS) and other related surface-enhanced spectroscopic processes resulted from the LSPR property. This dissertation describes the design and development of entirely new SERS nanosensors using a flexible SERS substrate based on the unique LSPR property of Au TNPs. The developed sensor shows an excellent SERS activity (enhancement factor = ~6.0 x 106) and limit of detection (as low as 56 parts-per-quadrillions) with high selectivity by chemometric analyses among three commonly used explosives (TNT, RDX, and PETN).
Further, we achieved the programmable self-assembly of Au TNPs using molecular tailoring to form a 3D supper lattice array based on the substrate effect. Here we achieved the highest reported sensitivity for potent drug analysis, including opioids and synthetic cannabinoids from human plasma obtained from the emergency room. This exquisite sensitivity is mainly due to the two reasons, including molecular resonance of the adsorbate molecules and the plasmonic coupling among the nanoparticles. Altogether we are highly optimistic that our research will not only increase the patient survival rate through early detection of cancer but also help to battle the “war against drugs” that together are expected to enhance the quality of human life.
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Paper Spray - Mass Spectrometry: Investigation of Sampling Devices for Illicit Drug Detection and QuantificationChau Bao Nguyen (11178123) 06 August 2021 (has links)
Different sampling devices for paper spray - mass spectrometry (PS - MS) were investigated to improve the assay’s simplicity and sensitivity over traditional approaches. In the first one, pressure-sensitive adhesive paper was used as both sampling tool to collect drug residues on surfaces and paper substrate in PS - MS analysis. This method showed a significant improvement in drug collection on surfaces leading to low nano-gram level detection limits. Other sampling device being investigated was snap-in solid-phase extraction column, which demonstrated the ability to detect trace amounts of drugs in plasma while allowed easy transportation and the use of PS - MS automated system.
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NANOPLASMONIC EFFICACY OF GOLD TRIANGULAR NANOPRISMS IN MEASUREMENT SCIENCE: APPLICATIONS RANGING FROM BIOMEDICAL TO FORENSIC SCIENCESThakshila Liyanage (8098115) 11 December 2019 (has links)
<p>Noble metal nanostructures display collective
oscillation of the surface conduction electrons upon light irradiation as a
form of localized surface plasmon resonance (LSPR) properties. Size, shape and
the refractive index of surrounding environment are the key features that
controls the LSPR properties. Surface passivating ligands have the ability to
modify the charge density of nanostructures to allow resonant wavelength to
match that of the incident light, a phenomenon called “plasmoelectric effect,”.
According to the drude model Red and blue shifts of LSPR peak of nanostructures
are observed in the event of reducing and increasing charge density,
respectively. However, herein we report unusual LSPR properties of gold triangular
nanoprisms (Au TNPs) upon functionalization with para-substituted thiophenols
(X-Ph-SH, X = -NH<sub>2</sub>, -OCH<sub>3</sub>, -CH<sub>3</sub>, -H, -Cl, -CF<sub>3</sub>,
and -NO<sub>2</sub>). Accordingly, we hypothesized that an appropriate energy
level alignment between the Au Fermi energy and the HOMO or LUMO of ligands
allows delocalization of surface plasmon excitation at the hybrid
inorganic-organic interface, and thus provides a thermodynamically driven
plasmoelectric effect. We further validated our hypothesis by calculating the
HOMO and LUMO levels and also work function changes of Au TNPs upon
functionalization with para substituted thiol. We further utilized our unique
finding to design ultrasensitive plasmonic substrate for biosensing of cancer
microRNA in bladder cancer and owe to unpresidential sensitivity of the
developed Au TNPs based LSPR sensor, for the first time we have been utilized
to analysis the tumor suppressor microRNA for more accurate diagnosis of BC.
Additionally, we have been advancing our sensing platform to mitigate the false
positive and negative responses of the sensing platform using surface enhanced
fluorescence technique. This noninvasive, highly sensitive,
highly specific, also does not have false positives technique provide strong
key to detect cancer at very early stage, hence increase the cancer survival
rate. Moreover, the electromagnetic
field enhancement of Surface-Enhanced Raman Scattering (SERS) and other related
surface-enhanced spectroscopic processes resulted from the LSPR property. This
dissertation describes the design and development of entirely
new SERS nanosensors using flexible SERS substrate based on unique LSPR
property of Au TNPs and developed sensors shows excellent SERS activity
(enhancement factor = ~6.0 x 106) and limit of detection (as low as 56
parts-per-quadrillions) with high selectivity by chemometric analyses among
three commonly used explosives (TNT, RDX, and PETN). Further we achieved the
programable self-assembly of Au TNPs using molecular tailoring to form a 3D
supper lattice array based on the substrate effect. Here we achieved the
highest reported sensitivity for potent drug analysis, including opioids and
synthetic cannabinoids from human plasma obtained from the emergency room. This
exquisite sensitivity is mainly due to the two reasons, including molecular
resonance of the adsorbate molecules and the plasmonic coupling among the
nanoparticles. Altogether we are highly optimistic that our research will not
only increase the patient survival rate through early detection of cancer but
also help to battle the “war against drugs” that together is expected to
enhance the quality of human life. </p>
<p> </p>
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Development and Testing of a Near-Infrared Spectroscopy Opioid Overdose Detection DeviceMichael D Maclean (8795939) 12 October 2021 (has links)
Opioid overdose is a growing epidemic plaguing the United States. Overdose related death
has risen from 16,849 in 1999 to 69,029 in 2018. Almost 7 out of 10 of these deaths were
due to opioids with 47% being caused by fentanyl or other synthetic opioids. There is a
strong need to reduce the amount of overdose-related deaths. Indirect methods should
be a first priority, and include counseling and care. For some individuals, this treatment
option is unavailable because the drug user may not have the desire or economic means
to pursue it. In this case, a more direct preventative approach is needed. This paper
presents a novel method of detecting poor peripheral oxygenation, a biomarker linked to
opioid overdose. A wristwatch near-infrared spectroscopy device (NIRS) was developed.
SPICE simulations were conducted to confirm proper operation of electrical systems. The
device was fabricated on a printed circuit board and mounted to a 3D printed enclosure.
Absorbance of green, red and infrared (IR) light were measured. Additionally, peripheral
capillary oxygen saturation (SpO2) modulation index and changes in concentration of
oxyhemoglobin and deoxyhemoglobin were calculated from raw data. A brachial occlusion test was performed to mimic the effects of opioid overdose on peripheral oxygenation.
A statistically significant difference (p < 0.05) was observed between pre-occlusion and
during-occlusion groups in two subjects for measurement of peak-to-peak values of green
raw data, red raw data, IR raw data, oxyhemoglobin concentration change, and deoxyhemoglobin concentration change. Peak-to-peak was observed as a consistent indicator of
poor peripheral oxygenation and could serve as a useful metric in the detection of opioid
overdose.
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