Emerging potentials of Fe-based nanomaterials for chiral sensing and imaging.

Fe-based nanostructures have possessed promising properties that make it suitable for chiral sensing and imaging applications owing to their ultra-small size, non-toxicity, biocompatibility, excellent photostability, tunable fluorescence, and water solubility. This review summarizes the recent research progress in the field of Fe-based nanostructures and places special emphases on their applications in chiral sensing and imaging. The synthetic strategies to prepare the targeted Fe-based structures were also introduced. The chiral sensing and imaging applications of the nanostructures are discussed in details.

Magnetoplasmonic photonic arrays for rapid and selective colorimetric detection of chloride ions in water.

The rapid and efficient detection of chloride (Cl-) ions is crucial in a variety of fields, making the development of advanced sensing methods such as colorimetric sensors an imperative advancement in analytical chemistry. Herein, a novel, selective, and straightforward paper-based colorimetric sensing platform has been developed utilizing an amorphous photonic array (APA) of magnetoplasmonic Ag@Fe3O4 nanoparticles (MagPlas NPs) for the detection of Cl- in water. Taking advantage of the highly responsive APA, the key principle of this sensing method is based on the chemical reaction between Ag+ and Cl-, which results in the precipitation of high-refractive index (RI) AgCl. This assay, distinct from typical plasmonic sensors that rely heavily on nanoparticle aggregation/anti-aggregation, is premised on the precipitation reaction of Ag+ and Cl-. In the presence of Cl-, a rapid, distinctive color alteration from royal purple to a dark sky blue is visually observable within a short time of a few minutes, eliminating the necessity for any surface modification procedures. Comprehensive assessments substantiated that these sensors display commendable sensitivity, selectivity, and stability, thereby establishing their effective applicability for Cl- analysis in various technological fields.

Rugged Forest Morphology of Magnetoplasmonic Nanorods that Collect Maximum Light for Photoelectrochemical Water Splitting.

A feasible nanoscale framework of heterogeneous plasmonic materials and proper surface engineering can enhance photoelectrochemical (PEC) water-splitting performance owing to increased light absorbance, efficient bulk carrier transport, and interfacial charge transfer. This article introduces a new magnetoplasmonic (MagPlas) Ni-doped Au@Fex Oy nanorods (NRs) based material as a novel photoanode for PEC water-splitting. A two stage procedure produces core-shell Ni/Au@Fex Oy MagPlas NRs. The first-step is a one-pot solvothermal synthesis of Au@Fex Oy . The hollow Fex Oy nanotubes (NTs) are a hybrid of Fe2 O3 and Fe3 O4 , and the second-step is a sequential hydrothermal treatment for Ni doping. Then, a transverse magnetic field-induced assembly is adopted to decorate Ni/Au@Fex Oy on FTO glass to be an artificially roughened morphologic surface called a rugged forest, allowing more light absorption and active electrochemical sites. Then, to characterize its optical and surface properties, COMSOL Multiphysics simulations are carried out. The core-shell Ni/Au@Fex Oy MagPlas NRs increase photoanode interface charge transfer to 2.73 mAcm-2 at 1.23 V RHE. This improvement is made possible by the rugged morphology of the NRs, which provide more active sites and oxygen vacancies as the hole transfer medium. The recent finding may provide light on plasmonic photocatalytic hybrids and surface morphology for effective PEC photoanodes.

Matrix-assisted laser desorption/ionization-Fourier-transform ion cyclotron resonance-mass spectrometry analysis of exosomal lipids from human serum.

RATIONALE: Exosomes contain biomarkers such as proteins and lipids that help in understanding normal physiology and diseases. Lipids, in particular, are infrequently studied using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) for biomarker discovery. In this study, MALDI was equipped with a high-resolution MS to investigate exosomal lipids from human serum. METHODS: Exosomal lipids were profiled using MALDI with Fourier-transform ion cyclotron resonance (FTICR)-MS. Four matrices (i.e., α-cyano-4-hydroxycinnamic acid [CHCA], 2,5-dihydroxybenzoic acid, sinapinic acid, and graphene oxide [GO]) and three sample preparation methods (i.e., dried droplet, thin layer, and two layer) were compared for the number of lipid species detected and the relative abundance of each lipid from human serum and human serum exosomes. RESULTS: In sum, 172 and 89 lipid species were identified from human serum and human serum exosomes, respectively, using all the methods. The highest number of exosome lipid species, 69, was detected using the CHCA matrix, whereas only 8 exosome lipid species were identified using the GO matrix. Among the identified lipid species, phosphatidylcholine was identified most frequently, probably due to the use of a positive ion mode. CONCLUSIONS: Exosomes and human serum showed comparable lipid profiles as determined using MALDI-FTICR-MS. These findings provide a new perspective on exosomal lipidomics analysis and may serve as a foundation for future lipidomics-based biomarker research using MALDI-FTICR-MS.

Effective inactivation of Bacillus atrophaeus spores and Escherichia coli on disposable face masks using ultraviolet laser irradiation.

Due to the widespread emergence of COVID-19, face masks have become a common tool for reducing transmission risk between people, increasing the need for sterilization methods against mask-contaminated microorganisms. In this study, we measured the efficacy of ultraviolet (UV) laser irradiation (266 nm) as a sterilization technique against Bacillus atrophaeus spores and Escherichia coli on three different types of face mask. The UV laser source demonstrated high penetration of inner mask layers, inactivating microorganisms in a short time while maintaining the particle filtration efficiency of the masks. This study demonstrates that UV laser irradiation is an efficient sterilization method for removing pathogens from face masks.

One-Pot Synthesis of Magnetoplasmonic Au@FexOy Nanowires: Bioinspired Bouligand Chiral Stack.

One-dimensional hybrid nanostructures composed of a plasmonic gold nanowire core covered by a shell of magnetic oxide nanoparticles (Au@FexOy NWs) were synthesized by a one-pot solvothermal synthesis process. The effects of reaction temperature, time, reducing agent, and precursor as well as postsynthesis treatment were optimized to produce highly uniform NWs with a diameter of 226 ± 25 nm and a plasmonic core aspect ratio of 25 to 82. By exploiting the interaction of NWs with an external magnetic field, precise arrangements into highly periodic photonic structures were achieved, which can generate distinctive structural colors that are vividly iridescent and polarization-sensitive. Furthermore, a Bouligand-type chiral nematic film consisting of multistacked unidirectional layers of achiral NWs was fabricated using a modified layer-by-layer deposition method, which displays circular dichroism (CD) and chiral sensing capability. The addition of bovine serum albumin (BSA) as a model protein analyte induced a concentration-dependent wavelength shift of CD peaks. These intriguing properties of magnetoplasmonic anisotropic NWs and their self-assemblies could be consequently valuable for developing nature-inspired structural color imprints as well as solid-state chiral sensing devices.

Sterilization effects of UV laser irradiation on Bacillus atrophaeus spore viability, structure, and proteins.

Bacillus spores are highly resistant to toxic chemicals and extreme environments. Because some Bacillus species threaten public health, spore inactivation techniques have been intensively investigated. We exposed Bacillus atrophaeus spores to a 266 nm Nd:YVO4 laser at a laser power of 1 W and various numbers of scans. As a result, the UV laser reduced the viability of Bacillus atrophaeus spores. Although the outer coat of spores remained intact after UV laser irradiation of 720 scans, damage inside the spores was observed. Spore proteins were identified by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry during the course of UV laser irradiation. Photochemical and photothermal processes are believed to be involved in the UV laser sterilization of Bacillus spores. Our findings suggest that a UV laser is capable of sterilizing Bacillus atrophaeus spores.

Label-free quantitative proteomic analysis of serum extracellular vesicles differentiating patients of alcoholic and nonalcoholic fatty liver diseases.

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are typically asymptomatic and slow-progressing but potentially fatal diseases that are common causes of liver cirrhosis and related complications. Exosomes are nano-sized extracellular vesicles that have been linked to various intercellular communication processes and can carry biological materials reflecting the state and severity of disease. In this study, shotgun proteomic analysis of the protein expression profiles of extracellular vesicles, including exosomes and microvesicles, enriched from human serum samples of 24 patients diagnosed with various fatty liver diseases was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS) followed by protein identification and label-free quantification using the MaxQuant platform. A total of 329 proteins, including 190 previously reported exosome-specific proteins, were identified from four types of liver disease, where significant differences in protein expression were found in apolipoproteins, immunoglobulins, and other previously reported markers of liver disease. Principal component analysis of 61 proteins identified from MaxQuant analysis of the LC-MS/MS data provided a confident differentiation between ALD and NAFLD. SIGNIFICANCE: The current investigation revealed the difference among various types of liver disease using LC-MS/MS of exosomes enriched from human serum samples of 24 patients where the most significantly up-regulation proteins were alpha-2-macroglobulin for alcoholic hepatitis and apolipoprotein C3 for nonalcoholic fatty liver disease.

MALDI-MS analysis of disaccharide isomers using graphene oxide as MALDI matrix.

Disaccharides are sugars composed of two monosaccharides joined by a glycosidic linkage. The specific properties of a disaccharide depend on the type of the glycosidic linkage and the identity of the two component monosaccharides. In this work, seven disaccharide isomers (gentiobiose, isomaltose, melibiose, lactose, maltose, cellobiose, and sucrose) were analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using a graphene oxide matrix. Each disaccharide was identified by its unique cleavage pattern. To determine the feasibility of quantitative analyses based on specific fragment patterns, mixtures of sucrose with cellobiose or maltose were prepared at different ratios and analyzed by MALDI-MS, where a strong linear correlation was observed between the relative peak intensity of the sucrose fragment peak at m/z 185 and the amount of sucrose in the mixture. The calibration curve was successfully applied to obtain the relative amount of maltose and sucrose in four different honey samples.

Photonic-Plasmonic Nanostructures for Solar Energy Utilization and Emerging Biosensors.

Issues related to global energy and environment as well as health crisis are currently some of the greatest challenges faced by humanity, which compel us to develop new pollution-free and sustainable energy sources, as well as next-generation biodiagnostic solutions. Optical functional nanostructures that manipulate and confine light on a nanometer scale have recently emerged as leading candidates for a wide range of applications in solar energy conversion and biosensing. In this review, recent research progress in the development of photonic and plasmonic nanostructures for various applications in solar energy conversion, such as photovoltaics, photothermal conversion, and photocatalysis, is highlighted. Furthermore, the combination of photonic and plasmonic nanostructures for developing high-efficiency solar energy conversion systems is explored and discussed. We also discuss recent applications of photonic-plasmonic-based biosensors in the rapid management of infectious diseases at point-of-care as well as terahertz biosensing and imaging for improving global health. Finally, we discuss the current challenges and future prospects associated with the existing solar energy conversion and biosensing systems.

Platelet Factor 4 as a Novel Exosome Marker in MALDI-MS Analysis of Exosomes from Human Serum.

Exosomes are nanosized vesicles commonly found in biological fluids as a result of a secretion process involving endosomes and multivesicular bodies. The isolation and analysis of exosomes can be useful for noninvasive clinical diagnosis of a variety of human diseases. We investigated the utility of analyzing exosomal proteins, using matrix-assisted laser desorption/ionization combined with Fourier-transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS), as a means of determining the presence of exosomes. MALDI-FTICR-MS analyses of exosomes enriched from human serum via centrifugation in a mass range of m/z 1000-20 000 yielded a distinctive protein around m/z 7766. The high mass accuracy and resolution of MALDI-FTICR-MS allowed for reliable comparisons against a protein database, through which the protein was identified as platelet factor 4 (PLF4), whose singly charged protein peak has an elemental composition of C341H577N96O101S4+, with a theoretical most abundant isotopic peak at m/z 7765.194 and a theoretical average peak at m/z 7766. The MALDI-TOF MS analysis of exosomes from the serum of 27 patients with different states of liver diseases provided the most abundant PLF4 peak for each mass spectrum, along with several additional minor peaks. In conclusion, MALDI-MS is suitable as an alternative exosome detection method, serving as a valuable confirmation tool, greatly decreasing the time and workload associated with exosome identification.

Effects of Matrices and Additives on Multiple Charge Formation of Proteins in MALDI-MS Analysis.

The sinapinic acid (SA) matrix has frequently been used for protein analysis in matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). However, the SA matrix does not result in the formation of distinctive multiple protein charge states, whereas the 2-nitrophloroglucinol (2-NPG) matrix is capable of this. The formation of multiple charge states in the MALDI-MS analysis of proteins is advantageous in that it results in higher accuracy. In this study, the mass spectra of several common standard proteins, namely cytochrome c, myoglobin, bovine serum albumin (BSA), and immunoglobulin G (IgG), were compared using various matrices (2,5-dihydroxybenzoic acid, α-cyano-hydroxycinnamic acid, SA, and 2-NPG). Furthermore, the mass spectra of two large standard proteins (BSA and IgG) using various acid additives (H3PO4, HNO3, H2SO4, HCl, and trifluoroacetic acid) with the 2-NPG matrix were also compared. Among the different matrices, 2-NPG provided the broadest range of multiple protein charge states, while, among the different additives, the 2-NPG matrix in combination with HCl generated the broadest multiple charge states as well as the most intense protein peaks.