The hazardous interactions of copper-dyed patient gowns with MRI: Two cases of superficial abdominal burns.

Magnetic resonance imaging is a commonly used imaging modality in medical procedures. Despite its prevalent use, unexpected adverse events such as burns can occur during an MRI procedure. The majority of the transmitted Radio Frequency power can be converted into heat within the patient's tissue due to resistive losses, leading to such incidents. In this study, we present an intriguing case of a patient who experienced an MRI-induced burn, presumably caused by the copper dye in the patient's gown. Notably, we observed frequent distortion of the MR image due to the patient's gown. The awareness and understanding of such potential adverse events are critical for clinicians and technicians to prevent future occurrences. Through this study, we aim to contribute to this critical area of patient safety during MRI procedures.

Toward Quantitative Surface-Enhanced Raman Scattering with Plasmonic Nanoparticles: Multiscale View on Heterogeneities in Particle Morphology, Surface Modification, Interface, and Analytical Protocols.

Surface-enhanced Raman scattering (SERS) provides significantly enhanced Raman scattering signals from molecules adsorbed on plasmonic nanostructures, as well as the molecules' vibrational fingerprints. Plasmonic nanoparticle systems are particularly powerful for SERS substrates as they provide a wide range of structural features and plasmonic couplings to boost the enhancement, often up to >108-1010. Nevertheless, nanoparticle-based SERS is not widely utilized as a means for reliable quantitative measurement of molecules largely due to limited controllability, uniformity, and scalability of plasmonic nanoparticles, poor molecular modification chemistry, and a lack of widely used analytical protocols for SERS. Furthermore, multiscale issues with plasmonic nanoparticle systems that range from atomic and molecular scales to assembled nanostructure scale are difficult to simultaneously control, analyze, and address. In this perspective, we introduce and discuss the design principles and key issues in preparing SERS nanoparticle substrates and the recent studies on the uniform and controllable synthesis and newly emerging machine learning-based analysis of plasmonic nanoparticle systems for quantitative SERS. Specifically, the multiscale point of view with plasmonic nanoparticle systems toward quantitative SERS is provided throughout this perspective. Furthermore, issues with correctly estimating and comparing SERS enhancement factors are discussed, and newly emerging statistical and artificial intelligence approaches for analyzing complex SERS systems are introduced and scrutinized to address challenges that cannot be fully resolved through synthetic improvements.

One-Pot Heterointerfacial Metamorphosis for Synthesis and Control of Widely Varying Heterostructured Nanoparticles.

Despite remarkable facileness and potential in forming a wide variety of heterostructured nanoparticles with extraordinary compositional and structural complexity, one-pot synthesis of multicomponent heterostructures is largely limited by the lack of fundamental mechanistic understanding, designing principles, and well-established, generally applicable chemical methods. Herein, we developed a one-pot heterointerfacial metamorphosis (1HIM) method that allows heterointerfaces inside a particle to undergo multiple equilibrium stages to form a variety of highly crystalline heterostructured nanoparticles at a relatively low temperature (<100 °C). As proof-of-concept experiments, it was shown that widely different single-crystalline semiconductor-metal anisotropic nanoparticles with synergistic chemical, spectroscopic, and band-gap-engineering properties, including a series of metal-semiconductor nanoframes with high structural and compositional tunability, can be formed by using the 1HIM approach. 1HIM offers a new paradigm to synthesize previously unobtainable or poorly controllable heterostructures with unique or synergistic properties and functions.

Innovation of EUS-guided transmural gallbladder drainage using a novel self-expanding metal stent.

Endoscopic ultrasonography (EUS)-guided transmural drainage has been accepted as a modality of choice in peripancreatic fluid collection and acute cholecystitis. Each type of stent, including double-pigtail plastic stents, tubular self-expandable metal stents (SEMS), and lumen-apposing metal stents, for these procedure has its own advantages and disadvantages. To overcome their disadvantages, this animal study evaluated the feasibility of a newly designed twisted fully covered SEMS with spiral coiled ends. We performed the EUS-guided cholecystogastrostomy with a newly developed metal stent in eight mini pigs with surgically induced gallbladder distension. This novel stent is a twisted fully covered SEMS with spiral coiled ends, a diameter of 8 mm, and a length of 6 cm. The stent has been maintained for four to seven weeks after EUS-guided cholecystogastrostomy. The primary outcome was the technical success rate, and the secondary outcomes were adverse events, stent dysfunction, stent removability, and fistula formation. The stent was placed successfully between the gallbladder and the stomach in all cases without any adverse event. We observed neither stent migration nor dysfunction during the study period, and all the stents were removed easily as scheduled. We confirmed successful cholecysto-gastric fistula formation at endoscopic and histologic level in all cases. EUS-guided transmural drainage and fistula formation using a new twisted fully covered metal stent with spiral coiled ends was technically feasible without any adverse event in this animal study. Further clinical studies are needed to evaluate its efficacy and safety in real practice.

Myoglobin and Polydopamine-Engineered Raman Nanoprobes for Detecting, Imaging, and Monitoring Reactive Oxygen Species in Biological Samples and Living Cells.

Highly reliable detection, imaging, and monitoring of reactive oxygen species (ROS) are critical for understanding and studying the biological roles and pathogenesis of ROS. This study describes the design and synthesis of myoglobin and polydopamine-engineered surface-enhanced Raman scattering (MP-SERS) nanoprobes with strong, tunable SERS signals that allow for specifically detecting and imaging ROS sensitively and quantitatively. The study shows that a polydopamine nanolayer can facilitate the modification of Raman-active myoglobins and satellite Au nanoparticles (s-AuNPs) to a plasmonic core AuNP (c-AuNP) in a controllable manner and the generation of plasmonically coupled hot spots between a c-AuNP and s-AuNPs that can induce strong SERS signals. The six-coordinated Fe(III)-OH2 of myoglobins in plasmonic hotspots is reacted with ROS (H2 O2 , •OH, and O2- ) to form Fe(IV)O. The characteristic Raman peaks of Fe(IV)O from the Fe-porphyrin is used to analyze and quantify ROS. This chemistry allows for these probes to detect ROS in solution and image ROS in cells in a highly designable, specific, and sensitive manner. This work shows that these MP-SERS probes allow for detecting and imaging ROS to differentiate cancerous cells from noncancerous cells. Importantly, for the first time, SERS-based monitoring of the autophagy process in living cells under starvation conditions is validated.

Sensitive, Quantitative Naked-Eye Biodetection with Polyhedral Cu Nanoshells.

One of the most heavily used methods in chemical and biological labeling, detection, and imaging is based on silver shell-based enhancement on Au nanoparticles (AuNPs) that is useful for amplifying Rayleigh scattering, colorimetric signal, surface-enhanced Raman scattering, and electrical signal, but poor structural controllability and nonspecific growth of silver shells have limited its applications, especially with respect to signal reproducibility and quantification. Here, a highly specific, well-defined Cu nanopolyhedral shell overgrowth chemistry is developed with the aid of polyethyleneimine (PEI) on AuNPs, and the use of this PEI-mediated Cu polyhedral nanoshell (CuP) chemistry is shown as a means of light-scattering signal enhancement for the development of naked-eye-based highly sensitive and quantitative detections of DNA and viruses. Remarkably, these CuPs are exclusively formed on AuNPs in a controllable manner, with no noticeable nonspecific CuP growth. The findings enable to acquire clearly visible signals without analytic instrumentation, detectable down to 8 × 10-15 m of DNA (anthrax sequence) and 2700 copies of viruses (noroviruses in clinical stool samples) with broad dynamic ranges on archetypal assay platforms. This new method provides a general platform in controlling Cu shell nanostructures and their optical signals, and opens up revenues for highly reliable, quantitative onsite naked-eye biodetection.

Transformative Heterointerface Evolution and Plasmonic Tuning of Anisotropic Trimetallic Nanoparticles.

Multicomponent nanoparticles that incorporate multiple nanocrystal domains into a single particle represent an important class of material with highly tailorable structures and properties. The controlled synthesis of multicomponent NPs with 3 or more components in the desired structure, particularly anisotropic structure, and property is, however, challenging. Here, we developed a polymer and galvanic replacement reaction-based transformative heterointerface evolution (THE) method to form and tune gold-copper-silver multimetallic anisotropic nanoparticles (MAPs) with well-defined configurations, including structural order, particle and junction geometry, giving rise to extraordinarily high tunability in the structural design, synthesis and optical property of trimetallic plasmonic nanoantenna structures. MAPs can easily, flexibly integrate multiple surface plasmon resonance (SPR) peaks and incorporate various plasmonic field localization and enhancement within one structure. Importantly, a heteronanojunction in these MAPs can be finely controlled and hence tune the SPR properties of these structures, widely covering UV, visible and near-infrared range. The development of the THE method and new findings in synthesis and property tuning of multicomponent nanostructures pave ways to the fabrication of highly tailored multicomponent nanohybrids and realization of their applications in optics, energy, catalysis and biotechnology.

The trisaccharide raffinose modulates epidermal differentiation through activation of liver X receptor.

The epidermal barrier function requires optimal keratinocyte differentiation and epidermal lipid synthesis. Liver X receptor (LXR) α and ß, are important transcriptional regulators of the epidermal gene expression. Here, we show that raffinose, a ubiquitously present trisaccharide in plants, activated the transcriptional activity of LXRα/ß, which led to the induction of genes required for keratinocyte differentiation such as involucrin and filaggrin, and genes involved in lipid metabolism and transport including SCD1 and ABCA1 in both HaCaT and normal human epidermal keratinocytes. Raffinose induced the expression of JunD and Fra1, and their DNA binding in the AP1 motif in the promoters of involucrin and loricrin. Interestingly, LXR bound the AP1 motif upon raffinose treatment, and conversely, JunD and Fra1 bound the LXR response element in promoters of LXR target genes, which indicates the presence of a postive cross-talk between LXR and AP1 in the regualtion of these genes. Finally, the effect of raffinose in epidermal barrier function was confirmed by applying raffinose in an ointment formulation to the skin of hairless mice. These findings suggest that raffinose could be examined as an ingredient in functional cosmetics and therapeutic agents for the treatment of cutaneous disorders associated with abnormal epidermal barrier function.

Synthesis, Optical Properties, and Multiplexed Raman Bio-Imaging of Surface Roughness-Controlled Nanobridged Nanogap Particles.

Plasmonic nanostructures are widely studied and used because of their useful size, shape, composition and assembled structure-based plasmonic properties. It is, however, highly challenging to precisely design, reproducibly synthesize and reliably utilize plasmonic nanostructures with enhanced optical properties. Here, we devise a facile synthetic method to generate Au surface roughness-controlled nanobridged nanogap particles (Au-RNNPs) with ultrasmall (≈1 nm) interior gap and tunable surface roughness in a highly controllable manner. Importantly, we found that particle surface roughness can be associated with and enhance the electromagnetic field inside the interior gap, and stronger nanogap-enhanced Raman scattering (NERS) signals can be generated from particles by increasing particle surface roughness. The finite-element method-based calculation results support and are matched well with the experimental results and suggest one needs to consider particle shape, nanogap and nanobridges simultaneously to understand and control the optical properties of this type of nanostructures. Finally, the potential of multiplexed Raman detection and imaging with RNNPs and the high-speed, high-resolution Raman bio-imaging of Au-RNNPs inside cells with a wide-field Raman imaging setup with liquid crystal tunable filter are demonstrated. Our results provide strategies and principles in designing and synthesizing plasmonically enhanced nanostructures and show potential for detecting and imaging Raman nanoprobes in a highly specific, sensitive and multiplexed manner.

Quantitative Plasmon Mode and Surface-Enhanced Raman Scattering Analyses of Strongly Coupled Plasmonic Nanotrimers with Diverse Geometries.

Here, we quantitatively monitored and analyzed the spectral redistributions of the coupled plasmonic modes of trimeric Au nanostructures with two ∼1 nm interparticle gaps and single-dye-labeled DNA in each gap as a function of varying trimer symmetries. Our precise Mie scattering measurement with the laser-scanning-assisted dark-field microscopy allows for individual visualization of the orientations of the radiation fields of the coupled plasmon modes of the trimers and analyzing the magnitude and direction of the surface-enhanced Raman scattering (SERS) signals from the individual plasmonic trimers. We found that the geometric transition from acute-angled trimer to linear trimer induces the red shift of the longitudinally polarized mode and the blue shift of the axially polarized mode. The finite element method (FEM) calculation results show the distinct "on" and "off" of the plasmonic modes at the two gaps of the trimer. Importantly, the single-molecule-level systematic correlation studies among the near-field, far-field, and surface-enhanced Raman scattering reveal that the SERS signals from the trimers are determined by the largely excited coupled plasmon between the two competing plasmon modes, longitudinal and axial modes. Further, the FEM calculation revealed that even 0.5 nm or smaller discrepancy in the sizes of two gaps of the linear trimer led to >10-fold difference in the SERS signal. Granted that two gap sizes are not likely to be completely the same in actual experiments, one of two gaps plays a more significant role in generating the SERS signal. Overall, this work provides the knowledge and handles for the understanding and systematic control of the magnitude and polarization direction of the both plasmonic response and SERS signal from trimeric nanostructures and sets up the platform for the optical properties and the applications of plasmonically coupled trimers and higher multimeric nanostructures.

Oxidative nanopeeling chemistry-based synthesis and photodynamic and photothermal therapeutic applications of plasmonic core-petal nanostructures.

The precise control of plasmonic nanostructures and their use for less invasive apoptotic pathway-based therapeutics are important but challenging. Here, we introduce a highly controlled synthetic strategy for plasmonic core-petal nanoparticles (CPNs) with massively branched and plasmonically coupled nanostructures. The formation of CPNs was facilitated by the gold chloride-induced oxidative disassembly and rupture of the polydopamine corona around Au nanoparticles and subsequent growth of Au nanopetals. We show that CPNs can act as multifunctional nanoprobes that induce dual photodynamic and photothermal therapeutic effects without a need for organic photosensitizers, coupled with the generation of reactive oxygen species (ROS), and allow for imaging and analyzing cells. Near-infrared laser-activated CPNs can optically monitor and efficiently kill cancer cells via apoptotic pathway by dual phototherapeutic effects and ROS-mediated oxidative intracellular damage with a relatively mild increase in temperature, low laser power, and short laser exposure time.

Plasmonic nanosnowmen with a conductive junction as highly tunable nanoantenna structures and sensitive, quantitative and multiplexable surface-enhanced Raman scattering probes.

The precise design and synthesis of plasmonic nanostructures allow us to manipulate, enhance, and utilize the optical characteristics of metallic materials. Although many multimeric structures (e.g., dimers) with interparticle nanogap have been heavily studied, the plasmonic nanostructures with a conductive junction have not been well studied mostly because of the lack of the reliable synthetic methods that can reproducibly and precisely generate a large number of the plasmonic nanostructures with a controllable conductive nanojunction. Here, we formed various asymmetric Au-Ag head-body nanosnowman structures with a highly controllable conductive nanojunction and studied their plasmon modes that cover from visible to near-infrared range, electromagnetic field enhancement, and surface-enhanced Raman scattering (SERS) properties. It was shown that change in the plasmonic neck region between Au head and Ag body nanoparticles and symmetry breaking using different sizes and compositions within a structure can readily and controllably introduce various plasmon modes and change the electromagnetic field inside and around a nanosnowman structure. The charge-transfer and capacitive coupling plasmon modes at low frequencies are tunable in the snowman structure, and subtle change in the conductive junction area of the nanosnowman dramatically affects the resulting electromagnetic field and optical signal. The relationships between the electromagnetic field distribution and enhancement in the snowman structure, excitation laser wavelength, and Raman dye were also studied, and it was found that the strongest electromagnetic field was observed in the crevice area on the junction and synthesizing a thinner and sharper neck junction is critical to generate the stronger electromagnetic field in the crevice area and to obtain the charge-transfer mode-based near-infrared signal. We have further shown that highly reproducible SERS signals can be generated from these nanosnowman structures with a linear dependence on particle concentration (5 fM to 1 pM) and the SERS-enhancement factor values of >10(8) can be obtained with the aid of the resonance effect in SERS. Finally, a wide range of LSPR bands with high tunability along with high structural reproducibility and high synthetic yield make the nanosnowman structures as very good candidates for practically useful multiple-wavelength-compatible, quantitative and sensitive SERS probes, and highly tunable nanoantenna structures.

Thiolated DNA-based chemistry and control in the structure and optical properties of plasmonic nanoparticles with ultrasmall interior nanogap.

The design, synthesis and control of plasmonic nanostructures, especially with ultrasmall plasmonically coupled nanogap (∼1 nm or smaller), are of significant interest and importance in chemistry, nanoscience, materials science, optics and nanobiotechnology. Here, we studied and established the thiolated DNA-based synthetic principles and methods in forming and controlling Au core-nanogap-Au shell structures [Au-nanobridged nanogap particles (Au-NNPs)] with various interior nanogap and Au shell structures. We found that differences in the binding affinities and modes among four different bases to Au core, DNA sequence, DNA grafting density and chemical reagents alter Au shell growth mechanism and interior nanogap-forming process on thiolated DNA-modified Au core. Importantly, poly A or poly C sequence creates a wider interior nanogap with a smoother Au shell, while poly T sequence results in a narrower interstitial interior gap with rougher Au shell, and on the basis of the electromagnetic field calculation and experimental results, we unraveled the relationships between the width of the interior plasmonic nanogap, Au shell structure, electromagnetic field and surface-enhanced Raman scattering. These principles and findings shown in this paper offer the fundamental basis for the thiolated DNA-based chemistry in forming and controlling metal nanostructures with ∼1 nm plasmonic gap and insight in the optical properties of the plasmonic NNPs, and these plasmonic nanogap structures are useful as strong and controllable optical signal-generating nanoprobes.

Directional synthesis and assembly of bimetallic nanosnowmen with DNA.

Synthesizing and assembling nanoscale building blocks to form anisotropic nanostructures with the desired composition and property are of paramount importance for the understanding and use of nanostructured materials. Here we report a salt-tuned synthetic strategy using DNA-modified Au nanoparticles (DNA-AuNPs) to form Au-Ag head-body nanosnowman structures in >95% yield. We propose a mechanism for the formation of asymmetric Au-Ag nanosnowmen from DNA-AuNPs, salts, and Ag-precursor-loaded polymers. Importantly, we show that oriented assemblies of various nanostructures are readily obtained using nanosnowmen with asymmetrically modified DNA as building blocks.