18 research outputs found
Graphene Oxide Nanoprisms for Sensitive Detection of Environmentally Important Aromatic Compounds with SERS
Recent advances in graphene-based
sensors have shown that heavily
oxidized (GO) and reduced graphene oxide (rGO) are attractive materials
for environmental sensing due to their unique chemical and physical
properties. We describe here the fabrication of nanostructured GO
assemblies with Ag nanoprisms for improved detection with surface
enhanced Raman scattering (SERS). Specifically, 100-Ī¼m-sized,
periodic-nanoprism-array domains were fabricated on top of the GO
layers by GO-assisted lithography (GOAL). The atomically thin GO underlayers
are shown to attract cyclic aromatic molecules to the surface, likely
via ĻāĻ stacking interactions. The close proximity
of the analyte to GO and nanoprism (NP) tips effectively suppresses
fluorescent background and affords a plausible tertiary enhancement
of photon emissions via an electron charge transfer (CT) process.
The adsorption of analyte to rGO-NP leads to the appearance and/or
shift of several Raman bands, which provided a means to gain molecular
insights into the graphene-enhanced scattering process. The analytical
merits were characterized with model compound Rhodamine 6G, where
the detection limit could reach subnanomolar concentrations. The nanoprism
GO substrates also prove effective for SERS multiplex measurement
of several legacy aromatic pollutants. Three tetrachlorobiphenyl isomers
could be identified from a mixture using their autonomous nonoverlapping
molecular fingerprints, and the substrate offers remarkable trace
detection of 2,2ā²,3,3ā²-tetrachlorobiphenyl (PCB-77)
Quantitation of Alpha-Glucosidase Activity Using Fluorinated Carbohydrate Array and MALDI-TOF-MS
Quantitation
of alpha-glucosidase (Ī±-GD) activity is of significance
to diagnosis of many diseases including Pompe disease and type II
diabetes. We report here a new method to determine Ī±-GD activity
using matrix-assisted laser desorption/ionization (MALDI)-time-of-flight
(TOF) mass spectrometry (MS) in combination with carbohydrate microarray
and affinity surface chemistry. Carbohydrate probes are synthesized
for capture of the enzymatic reaction products and the adducts are
loaded onto a fluorinated gold surface to generate an array, which
is followed by characterization by MALDI-TOF-MS. The ratio of intensities
is used to determine the level of activity of several enzymes. In
addition, half maximal inhibitory concentration (IC<sub>50</sub>)
of acarbose and epigallocatechin gallate are also determined using
this approach, and the results agree well with the reported values.
This method is advantageous as compared to conventional colorimetric
techniques that typically suffer matrix interference problems from
samples. The use of the polyfluorinated surface has effectively suppressed
the interference
Nanoglassified, Optically-Active Monolayer Films of Gold Nanoparticles for in Situ Orthogonal Detection by Localized Surface Plasmon Resonance and Surface-Assisted Laser Desorption/Ionization-MS
Localized
surface plasmon resonance (LSPR) represents a sensitive and versatile
method for detection of biomolecules in a label-free fashion, but
identification of bound analytes can be challenging with LSPR alone,
especially for samples in a complex medium. We report the fabrication
of an optically active, plasmonic film of gold nanoparticles by using
a self-assembly and calcination process, which offers orthogonal measurements
enabling multifaceted characterization on the same surface with LSPR
and surface-assisted laser desorption/ionization mass spectrometry.
This proof-of-concept study involves plasmonic characterization of
the fabricated nanofilm, real-time monitoring of vesicleāsurface
interactions toward formation of fluid lipid bilayer, and mass spectrometric
analysis of peptides and cytochrome c digest. This multifunction-enabling
surface material can yield complementary analytical information, providing
new tools for comprehensive analysis of biomolecular samples
On-Demand Formation of Supported Lipid Membrane Arrays by Trehalose-Assisted Vesicle Delivery for SPR Imaging
The fabrication of large-scale, solid-supported
lipid bilayer (SLB)
arrays has traditionally been an arduous and complex task, primarily
due to the need to maintain SLBs within an aqueous environment. In
this work, we demonstrate the use of trehalose vitrified phospholipid
vesicles that facilitate on-demand generation of microarrays, allowing
each element a unique composition, for the label-free and high-throughput
analysis of biomolecular interactions by SPR imaging (SPRi). Small,
unilamellar vesicles (SUVs) are suspended in trehalose, deposited
in a spatially defined manner, with the trehalose vitrifying on either
hydrophilic or hydrophobic SPR substrates. SLBs are subsequently spontaneously
formed on-demand simply by in situ hydration of the array in the SPR
instrument flow cell. The resulting SLBs exhibit high lateral mobility,
characteristic of fluidic cellular lipid membranes, and preserve the
biological function of embedded cell membrane receptors, as indicated
by SPR affinity measurements. Independent fluorescence and SPR imaging
studies show that the individual SLBs stay localized at the area of
deposition, without any encapsulating matrix, confining coral, or
boundaries. The introduced methodology allows individually addressable
SLB arrays to be analyzed with excellent label-free sensitivity in
a real-time, high-throughput manner. Various proteināganglioside
interactions have been selected as a model system to illustrate discrimination
of strong and weak binding responses in SPRi sensorgrams. This methodology
has been applied toward generating hybrid bilayer membranes on hydrophobic
SPR substrates, demonstrating its versatility toward a range of surfaces
and membrane geometries. The stability of the fabricated arrays, over
medium to long storage periods, was evaluated and found to be good.
The highly efficient and easily scalable nature of the method has
the potential to be applied to a variety of label-free sensing platforms
requiring lipid membranes for high-throughput analysis of their properties
and constituents
Thermoresponsive Arrays Patterned via Photoclick Chemistry: Smart MALDI Plate for Protein Digest Enrichment, Desalting, and Direct MS Analysis
Sample
desalting and concentration are crucial steps before matrix-assisted
laser desorption/ionization-mass spectrometry (MALDI-MS) analysis.
Current sample pretreatment approaches require tedious fabrication
and operation procedures, which are unamenable to high-throughput
analysis and also result in sample loss. Here, we report the development
of a smart MALDI substrate for on-plate desalting, enrichment, and
direct MS analysis of protein digests based on thermoresponsive, hydrophilic/hydrophobic
transition of surface-grafted polyĀ(<i>N</i>-isopropylacrylamide)
(PNIPAM) microarrays. Superhydrophilic 1-thioglycerol microwells are
first constructed on alkyneāsilane-functionalized rough indium
tin oxide substrates based on two sequential thiol-yne photoclick
reactions, whereas the surrounding regions are modified with hydrophobic
1<i>H</i>,1<i>H</i>,2<i>H</i>,2<i>H</i>-perfluorodecanethiol. Surface-initiated atom-transfer
radical polymerization is then triggered in microwells to form PNIPAM
arrays, which facilitate sample loading and enrichment of protein
digests by concentrating large-volume samples into small dots and
achieving on-plate desalting through PNIPAM configuration change at
elevated temperature. The smart MALDI plate shows high performance
for mass spectrometric analysis of cytochrome <i>c</i> and
neurotensin in the presence of 1 M urea and 100 mM NaHCO<sub>3</sub>, as well as improved detection sensitivity and high sequence coverage
for Ī±-casein and cytochrome <i>c</i> digests in femtomole
range. The work presents a versatile sample pretreatment platform
with great potential for proteomic research
Protein Recognition by a Self-Assembled Deep Cavitand Monolayer on a Gold Substrate
This paper details the first use of a self-folding deep
cavitand
on a gold surface. A sulfide-footed deep, self-folding cavitand has
been synthesized, and its attachment to a cleaned gold surface studied
by electrochemical and SPR methods. Complete monolayer formation is
possible if the cavitand folding is templated by noncovalent binding
of choline or by addition of space-filling thiols to cover any gaps
in the cavitand adsorption layer. The cavitand is capable of binding
trimethylammonium-tagged guests from an aqueous medium and can be
deposited in 2 Ć 2 microarrays on the surface for characterization
by SPR imaging techniques. When biotin-labeled guests are used, the
cavitand:guest construct can recognize and immobilize streptavidin
proteins from aqueous solution, acting as an effective supramolecular
biosensor for monitoring protein recognition
Dual-Mode Optical Sensing of Organic Vapors and Proteins with Polydiacetylene (PDA)-Embedded Electrospun Nanofibers
Optical
sensors capable of colorimetric visualization and/or fluorescence
detection have shown tremendous potential for field technicians and
emergency responders, owing to the portability and low cost of such
devices. Polydiacetylene (PDA)-enhanced nanofibers are particularly
promising due to high surface area, facile functionalization, simple
construction, and the versatility to empower either colorimetric or
fluorescence signaling. We demonstrate here a dual-mode optical sensing
with electrospun nanofibers embedded with various PDAs. The solvent-dependent
fluorescent transition of nanofibers generated a pattern that successfully
distinguished four common organic solvents. The colorimetric and fluorescent
sensing of biotināavidin interactions by embedding biotinylated-PCDA
monomers into silica-reinforced nanofiber mats were realized for detection
of biomolecules. Finally, a PDA-based nanofiber sensor array consisting
of three monomers has been fabricated for the determination and identification
of organic amine vapors using colorimetry and principal component
analysis (PCA). The combination of PCA and the strategy of probing
analytes in two different concentration ranges (ppm and ppth) led
to successful analysis of all eight amines
Image_1_Immunogenic cell death related risk model to delineate ferroptosis pathway and predict immunotherapy response of patients with GBM.jpeg
Immunogenic cell death (ICD) is a type of cell death that leads to the regulation and activation of the immune response, which is marked by the exposure and delivery of damageāassociated molecular patterns (DAMPs) in the tumor microenvironment. Accumulating evidence has revealed the significance of ICD-related genes in tumor progression and therapeutic response. In this study, we obtained two ICD-related clusters for glioblastoma (GBM) by applying consensus clustering, and further constructed a risk signature on account of the prognostic ICD genes. Based on the risk signature, we found that higher risk scores were associated with worse patient prognosis. Besides, the results illustrated that ferroptosis regulators/markers were highly enriched the high-risk group, and ferroptosis were correlated with cytokine signaling pathway and other immune-related pathways. We also discovered that high-risk scores were correlated to specific immune infiltration patterns and good response to immune checkpoint blockade (ICB) treatment. In conclusion, our study highlights the significance of ICD-related genes as prognostic biomarkers and immune response indicators in GBM. And the risk signature integrating prognostic genes possessed significant potential value to predict the prognosis of patients and the efficacy of ICB treatment.</p
Presentation_1_Tumor-secreted lactate contributes to an immunosuppressive microenvironment and affects CD8 T-cell infiltration in glioblastoma.pdf
IntroductionGlioblastoma is a malignant brain tumor with poor prognosis. Lactate is the main product of tumor cells, and its secretion may relate to immunocytesā activation. However, its role in glioblastoma is poorly understood. MethodsThis work performed bulk RNA-seq analysis and single cell RNA-seq analysis to explore the role of lactate in glioblastoma progression. Over 1400 glioblastoma samples were grouped into different clusters according to their expression and the results were validated with our own data, the xiangya cohort. Immunocytes infiltration analysis, immunogram and the map of immune checkpoint genesā expression were applied to analyze the potential connection between the lactate level with tumor immune microenvironment. Furthermore, machine learning algorithms and cell-cell interaction algorithm were introduced to reveal the connection of tumor cells with immunocytes. By co-culturing CD8 T cells with tumor cells, and performing immunohistochemistry on Xiangya cohort samples further validated results from previous analysis.DiscussionIn this work, lactate is proved that contributes to glioblastoma immune suppressive microenvironment. High level of lactate in tumor microenvironment can affect CD8 T cellsā migration and infiltration ratio in glioblastoma. To step further, potential compounds that targets to samples from different groups were also predicted for future exploration.</p
Image_2_Immunogenic cell death related risk model to delineate ferroptosis pathway and predict immunotherapy response of patients with GBM.jpeg
Immunogenic cell death (ICD) is a type of cell death that leads to the regulation and activation of the immune response, which is marked by the exposure and delivery of damageāassociated molecular patterns (DAMPs) in the tumor microenvironment. Accumulating evidence has revealed the significance of ICD-related genes in tumor progression and therapeutic response. In this study, we obtained two ICD-related clusters for glioblastoma (GBM) by applying consensus clustering, and further constructed a risk signature on account of the prognostic ICD genes. Based on the risk signature, we found that higher risk scores were associated with worse patient prognosis. Besides, the results illustrated that ferroptosis regulators/markers were highly enriched the high-risk group, and ferroptosis were correlated with cytokine signaling pathway and other immune-related pathways. We also discovered that high-risk scores were correlated to specific immune infiltration patterns and good response to immune checkpoint blockade (ICB) treatment. In conclusion, our study highlights the significance of ICD-related genes as prognostic biomarkers and immune response indicators in GBM. And the risk signature integrating prognostic genes possessed significant potential value to predict the prognosis of patients and the efficacy of ICB treatment.</p