Superhydrophobic Surface Modification of Polymer Microneedles Enables Fabrication of Multimodal Surface-Enhanced Raman Spectroscopy and Mass Spectrometry Substrates for Synthetic Drug Detection in Blood Plasma.

Microneedles are widely used substrates for various chemical and biological sensing applications utilizing surface-enhanced Raman spectroscopy (SERS), which is indeed a highly sensitive and specific analytical approach. This article reports the fabrication of a nanoparticle (NP)-decorated microneedle substrate that is both a SERS substrate and a substrate-supported electrospray ionization (ssESI) mass spectrometry (MS) sample ionization platform. Polymeric ligand-functionalized gold nanorods (Au NRs) are adsorbed onto superhydrophobic surface-modified polydimethylsiloxane (PDMS) microneedles through the control of various interfacial interactions.

Hybrid Metal-Ligand Interfacial Dipole Engineering of Functional Plasmonic Nanostructures for Extraordinary Responses of Optoelectronic Properties.

Programmable manipulation of inorganic-organic interfacial electronic properties of ligand-functionalized plasmonic nanoparticles (NPs) is the key parameter dictating their applications such as catalysis, photovoltaics, and biosensing. Here we report the localized surface plasmon resonance (LSPR) properties of gold triangular nanoprisms (Au TNPs) in solid state that are functionalized with dipolar, conjugated ligands. A library of thiocinnamate ligands with varying surface dipole moments were used to functionalize TNPs, which results in ∼150 nm reversible tunability of LSPR peak wavelength with significant peak broadening (∼230 meV).

β Cell microRNAs Function as Molecular Hubs of Type 1 Diabetes Pathogenesis and as Biomarkers of Diabetes Risk.

MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial role in modulating gene expression and are enriched in cell-derived extracellular vesicles (EVs). We investigated whether miRNAs from human islets and islet-derived EVs could provide insight into β cell stress pathways activated during type 1 diabetes (T1D) evolution, therefore serving as potential disease biomarkers. We treated human islets from 10 cadaveric donors with IL-1β and IFN-γ to model T1D .

Amplification-Free, High-Throughput Nanoplasmonic Quantification of Circulating MicroRNAs in Unprocessed Plasma Microsamples for Earlier Pancreatic Cancer Detection.

Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy that is often detected at an advanced stage. Earlier diagnosis of PDAC is key to reducing mortality. Circulating biomarkers such as microRNAs are gaining interest, but existing technologies require large sample volumes, amplification steps, extensive biofluid processing, lack sensitivity, and are low-throughput.

Gabapentin Disrupts Binding of Perlecan to the αδ Voltage Sensitive Calcium Channel Subunit and Impairs Skeletal Mechanosensation.

Our understanding of how osteocytes, the principal mechanosensors within bone, sense and perceive force remains unclear. Previous work identified "tethering elements" (TEs) spanning the pericellular space of osteocytes and transmitting mechanical information into biochemical signals. While we identified the heparan sulfate proteoglycan perlecan (PLN) as a component of these TEs, PLN must attach to the cell surface to induce biochemical responses.

Selective Detection and Ultrasensitive Quantification of SARS-CoV-2 IgG Antibodies in Clinical Plasma Samples Using Epitope-Modified Nanoplasmonic Biosensing Platforms.

Monitoring the human immune response by assaying (detection and quantification) the antibody level against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important in conducting epidemiological surveillance and immunization studies at a population level. Herein, we present the design and fabrication of a solid-state nanoplasmonic biosensing platform that is capable of quantifying SARS-CoV-2 neutralizing antibody IgG with a limit of detection as low as 30.0 attomolar (aM) and a wide dynamic range spanning seven orders of magnitude.

Covalent Surface Modification of TiCT MXene with Chemically Active Polymeric Ligands Producing Highly Conductive and Ordered Microstructure Films.

As interest continues to grow in TiCT and other related MXenes, advancement in methods of manipulation of their surface functional groups beyond synthesis-based surface terminations (T: -F, -OH, and ═O) can provide mechanisms to enhance solution processability as well as produce improved solid-state device architectures and coatings. Here, we report a chemically important surface modification approach in which "" polymers, polyethylene glycol carboxylic acid (PEG6-COOH), are covalently attached onto MXenes esterification chemistry. Surface modification of TiCT with PEG6-COOH with large ligand loading (up to 14% by mass) greatly enhances dispersibility in a wide range of nonpolar organic solvents (.

Photoswitchable Machine-Engineered Plasmonic Nanosystem with High Optical Response for Ultrasensitive Detection of microRNAs and Proteins Adaptively.

Modulating optoelectronic properties of inorganic nanostructures tethered with light-responsive molecular switches by their conformational change in the solid state is fundamentally important for advanced nanoscale-device fabrication, specifically in biosensing applications. Herein, we present an entirely new solid-state design approach employing the light-induced reversible conformational change of spiropyran (SP)-merocyanine (MC) covalently attached to gold triangular nanoprisms (Au TNPs) via alkylthiolate self-assembled monolayers to produce a large localized surface plasmon resonance response (∼24 nm). This shift is consistent with the increase in thickness of the local dielectric shell-surrounded TNPs and perhaps short-range dipole-dipole (permanent and induced) interactions between TNPs and the zwitterionic MC form.

Multiplexed and High-Throughput Label-Free Detection of RNA/Spike Protein/IgG/IgM Biomarkers of SARS-CoV-2 Infection Utilizing Nanoplasmonic Biosensors.

To tackle the COVID-19 outbreak, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is an unmet need for highly accurate diagnostic tests at all stages of infection with rapid results and high specificity. Here, we present a label-free nanoplasmonic biosensor-based, multiplex screening test for COVID-19 that can quantitatively detect 10 different biomarkers (6 viral nucleic acid genes, 2 spike protein subunits, and 2 antibodies) with a limit of detection in the aM range, all within one biosensor platform. Our newly developed nanoplasmonic biosensors demonstrate high specificity, which is of the upmost importance to avoid false responses.

Enhancing Nonfouling and Sensitivity of Surface-Enhanced Raman Scattering Substrates for Potent Drug Analysis in Blood Plasma via Fabrication of a Flexible Plasmonic Patch.

Surface-enhanced Raman scattering (SERS) is an ultrasensitive analytical technique, which is capable of providing high specificity; thus, it can be used for toxicological drug assay (detection and quantification). However, SERS-based drug analysis directly in human biofluids requires mitigation of fouling and nonspecificity effects that commonly appeared from unwanted adsorption of endogenous biomolecules present in biofluids (e.g.

Optimization of electromagnetic hot spots in surface-enhanced Raman scattering substrates for an ultrasensitive drug assay of emergency department patients' plasma.

Herein we report the programmable preparation of ultrasensitive surface-enhanced Raman scattering (SERS)-based nanoplasmonic superlattice substrates to assay fentanyl and cocaine (detection and quantification) from 10 μL aliquots of emergency department patient plasma without the need for purification steps. Highly homogeneous three-dimensional (3D) nanoplasmonic superlattices are generated through the droplet evaporation-based self-assembly process of chemically-synthesized, polyethylene glycol thiolate-coated gold triangular nanoprisms (Au TNPs). Close-packed, solid-state 3D superlattice substrates produce electromagnetic hot spots due to near-field plasmonic coupling of Au TNPs, which display unique localized surface plasmonic resonance properties.

A novel liquid biopsy-based approach for highly specific cancer diagnostics: mitigating false responses in assaying patient plasma-derived circulating microRNAs through combined SERS and plasmon-enhanced fluorescence analyses.

Studies have shown that microRNAs, which are small noncoding RNAs, hold tremendous promise as next-generation circulating biomarkers for early cancer detection via liquid biopsies. A novel, solid-state nanoplasmonic sensor capable of assaying circulating microRNAs through a combined surface-enhanced Raman scattering (SERS) and plasmon-enhanced fluorescence (PEF) approach has been developed. Here, the unique localized surface plasmon resonance properties of chemically-synthesized gold triangular nanoprisms (Au TNPs) are utilized to create large SERS and PEF enhancements.

Ultrathin Plasmonic Tungsten Oxide Quantum Wells with Controllable Free Carrier Densities.

Localized surface plasmon resonances (LSPR) of nanostructures can be tuned by controlling their morphology, local dielectric environment, and free carrier concentration. We report the colloidal synthesis of an ∼3 tungsten-oxygen (W-O) layer thick (∼1 nm), two-dimensional (2D) WO nanoplatelets (NPLs) ( ≈ 0.55-1.

Reversible Tuning of the Plasmoelectric Effect in Noble Metal Nanostructures Through Manipulation of Organic Ligand Energy Levels.

Ligand-controlled tuning of localized surface plasmon resonance (LSPR) properties of noble metal nanostructures is fundamentally important for various optoelectronic applications such as photocatalysis, photovoltaics, and sensing. Here we demonstrate that the free carrier concentration of gold triangular nanoprisms (Au TNPs) can be tuned up to 12% upon functionalization of their surface with different para-substituted thiophenolate (X-Ph-S-) ligands. We achieve this unprecedentedly large optical response (plasmoelectric effect) in TNPs through the selective manipulation of electronic processes at the Au-thiolate interface.

Flexible Polymer-Assisted Mesoscale Self-Assembly of Colloidal CsPbBr Perovskite Nanocrystals into Higher Order Superstructures with Strong Inter-Nanocrystal Electronic Coupling.

Surface-passivating ligands, although ubiquitous to colloidal nanocrystal (NC) syntheses, play a role in assembling NCs into higher order structures and hierarchical superstructures, which has not been demonstrated yet for colloidal CsPbX (X = Cl, Br, and I) NCs. In this work, we report that functional poly(ethylene glycols) (PEG-Y, Y = -COOH and -NH) represent unique surface-passivating ligands enabling the synthesis of near-uniform CsPbBr NCs with diameters of 3.0 nm.

Plasmoelectronic-Based Ultrasensitive Assay of Tumor Suppressor microRNAs Directly in Patient Plasma: Design of Highly Specific Early Cancer Diagnostic Technology.

It is becoming understood that microRNAs hold great promise for noninvasive liquid biopsies for screening for different types of cancer, but current state-of-the-art RT-PCR and microarray techniques have sensitivity limitations that currently restrict their use. Herein, we report a new transduction mechanism involving delocalization of photoexcited conduction electrons wave function of gold triangular nanoprism (Au TNP) in the presence of -ssDNA/microRNA duplexes. This plasmoelectronic effect increases the electronic dimension of Au TNPs and substantially affects their localized surface plasmon resonance (LSPR) properties that together allow us to achieve a sensitivity for microRNA assay as low as 140 zeptomolar concentrations for our nanoplasmonic sensors.

Fabrication of a self-assembled and flexible SERS nanosensor for explosive detection at parts-per-quadrillion levels from fingerprints.

Apart from high sensitivity and selectivity of surface-enhanced Raman scattering (SERS)-based trace explosive detection, efficient sampling of explosive residue from real world surfaces is very important for homeland security applications. Herein, we demonstrate an entirely new SERS nanosensor fabrication approach. The SERS nanosensor was prepared by self-assembling chemically synthesized gold triangular nanoprisms (Au TNPs), which we show display strong electromagnetic field enhancements at the sharp tips and edges, onto a pressure-sensitive flexible adhesive film.

Elucidating the role of surface passivating ligand structural parameters in hole wave function delocalization in semiconductor cluster molecules.

This article describes the mechanisms underlying electronic interactions between surface passivating ligands and (CdSe) semiconductor cluster molecules (SCMs) that facilitate band-gap engineering through the delocalization of hole wave functions without altering their inorganic core. We show here both experimentally and through density functional theory calculations that the expansion of the hole wave function beyond the SCM boundary into the ligand monolayer depends not only on the pre-binding energetic alignment of interfacial orbitals between the SCM and surface passivating ligands but is also strongly influenced by definable ligand structural parameters such as the extent of their π-conjugation [π-delocalization energy; pyrene (Py), anthracene (Anth), naphthalene (Naph), and phenyl (Ph)], binding mode [dithiocarbamate (DTC, -NH-CS), carboxylate (-COO), and amine (-NH)], and binding head group [-SH, -SeH, and -TeH]. We observe an unprecedentedly large ∼650 meV red-shift in the lowest energy optical absorption band of (CdSe) SCMs upon passivating their surface with Py-DTC ligands and the trend is found to be Ph- < Naph- < Anth- < Py-DTC.

Achieving biosensing at attomolar concentrations of cardiac troponin T in human biofluids by developing a label-free nanoplasmonic analytical assay.

Acute myocardial infarction (heart attack) is the fifth leading cause of death in the United States (Dariush et al., Circulation, 2015, 131, e29-e322). This highlights the need for early, rapid, and sensitive detection of its occurrence and severity through assaying cardiac biomarkers in human fluids.

Pure white-light emitting ultrasmall organic-inorganic hybrid perovskite nanoclusters.

Organic-inorganic hybrid perovskites, direct band-gap semiconductors, have shown tremendous promise for optoelectronic device fabrication. We report the first colloidal synthetic approach to prepare ultrasmall (∼1.5 nm diameter), white-light emitting, organic-inorganic hybrid perovskite nanoclusters.

Dual Role of Electron-Accepting Metal-Carboxylate Ligands: Reversible Expansion of Exciton Delocalization and Passivation of Nonradiative Trap-States in Molecule-like CdSe Nanocrystals.

This paper reports large bathochromic shifts of up to 260 meV in both the excitonic absorption and emission peaks of oleylamine (OLA)-passivated molecule-like (CdSe) nanocrystals caused by postsynthetic treatment with the electron accepting Cd(OCPh) complex at room temperature. These shifts are found to be reversible upon removal of Cd(OCPh) by N,N,N',N'-tetramethylethylene-1,2-diamine. H NMR and FTIR characterizations of the nanocrystals demonstrate that the OLA remained attached to the surface of the nanocrystals during the reversible removal of Cd(OCPh).

Label-Free Nanoplasmonic-Based Short Noncoding RNA Sensing at Attomolar Concentrations Allows for Quantitative and Highly Specific Assay of MicroRNA-10b in Biological Fluids and Circulating Exosomes.

MicroRNAs are short noncoding RNAs consisting of 18-25 nucleotides that target specific mRNA moieties for translational repression or degradation, thereby modulating numerous biological processes. Although microRNAs have the ability to behave like oncogenes or tumor suppressors in a cell-autonomous manner, their exact roles following release into the circulation are only now being unraveled and it is important to establish sensitive assays to measure their levels in different compartments in the circulation. Here, an ultrasensitive localized surface plasmon resonance (LSPR)-based microRNA sensor with single nucleotide specificity was developed using chemically synthesized gold nanoprisms attached onto a solid substrate with unprecedented long-term stability and reversibility.

Solvent-like ligand-coated ultrasmall cadmium selenide nanocrystals: strong electronic coupling in a self-organized assembly.

Strong inter-nanocrystal electronic coupling is a prerequisite for delocalization of exciton wave functions and high conductivity. We report 170 meV electronic coupling energy of short chain poly(ethylene glycol) thiolate-coated ultrasmall (<2.5 nm in diameter) CdSe semiconductor nanocrystals (SNCs) in solution.

Highly specific plasmonic biosensors for ultrasensitive microRNA detection in plasma from pancreatic cancer patients.

MicroRNAs (miRs) are small noncoding RNAs that regulate mRNA stability and/or translation. Because of their release into the circulation and their remarkable stability, miR levels in plasma and other biological fluids can serve as diagnostic and prognostic disease biomarkers. However, quantifying miRs in the circulation is challenging due to issues with sensitivity and specificity.