Sterilization efficacy of a homemade UV lamp system on ceramic and porcelain tiles.

Ultraviolet (UV) sterilization of Bacillus atrophaeus spores attached to eight types of tiles, consisting of combinations of ceramic and porcelain, white and black, and matte and glossy surfaces, was investigated using a homemade UV lamp system with different irradiation times (10 s, 30 s, and 60 s) and UV lamp-to-tile distances (32 mm, 76 mm, and 120 mm). The results demonstrated a reduction in colony numbers with increasing irradiation time and decreasing lamp-to-tile distance, with nearly complete sterilization observed for a 120 mm lamp-to-tile distance with 60 s UV irradiation and for a 32 mm lamp-to-tile distance with 10 s UV irradiation. Specifically, superior UV sterilization efficacy was observed on porcelain compared to ceramic tiles, on white compared to black tiles, and on matte compared to glossy tiles, consistent with the reflectance trend. In conclusion, among the tested tile surfaces, the white matte porcelain tile exhibited the most efficient UV sterilization, attributed to its highest UV reflectance.

Analysis of Self-Assembled Micelle Inhibitory RNA (SAMiRNA) Drug Using Ion-Pairing Reversed-Phase Liquid Chromatography Combined with Mass Spectrometry.

Small interfering RNA (siRNA) is known for its ability to silence the expression of specific genes, demonstrating its promising potential as a therapeutic approach. Self-assembled micelle inhibitory RNA (SAMiRNA) is an oligonucleotide duplex developed to overcome the in vivo delivery limitations of siRNA. SAMiRNA has hydrophilic and hydrophobic groups at both ends of a sense strand, forming a spherical nanostructure that enhances the in vivo delivery efficiency. Ion-pairing reversed-phase liquid chromatography (IP-RPLC) is the most commonly used method for the analysis of oligonucleotides. Since SAMiRNA is heavily chemically modified, the behavior of SAMiRNA in IP-RPLC combined with mass spectrometry (MS) is anticipated to differ from that of the conventional siRNA drug. The current investigation using IP-RPLC-MS revealed that a distinct duplex peak along with two minor separate strands of antisense and sense was observed at column temperatures below 35 °C in the IP-RPLC system with a 100 mM ammonium bicarbonate buffer system. At column temperatures higher than 35 °C, however, two fully denatured single strands were observed. The mass spectrum from the chromatographic peak of the SAMiRNA duplex contained signals from the duplex, the antisense, and the sense, probably due to duplex denaturation during the MS ionization process. The current comprehensive analysis results will make a substantial contribution to the future application of IP-RPLC-MS in the analysis of SAMiRNA.

Ultraviolet Light-Assisted Decontamination of Chemical Warfare Agent Simulant 2-Chloroethyl Phenyl Sulfide on Metal-Loaded TiO2 /Ti Surfaces.

The application of ultraviolet (UV) light for the decontamination of chemical warfare agents (CWAs) has gained recognition as an effective method, especially for treating hard-to-reach areas where wet chemical methods are impractical. In this study, TiO2 /Ti was employed as a model catalyst, which was contaminated with 2-chloroethyl phenyl sulfide (CEPS), and subjected to photocatalytic decontamination using both UVB and UVC light. Additionally, photocatalytic decontamination efficiency by introducing Au, Pt, and Cu onto the TiO2 /Ti surface was explored. During the photodecomposition process under UVC light, at least eight distinct secondary byproducts were identified. It was observed that the introduction of overlayer metals did not significantly enhance the photodecomposition under UVC light instead overlaid Au exhibited substantially improved activity under UVB light. Whereas, photodecomposition process under UVB light, only five secondary products were detected, including novel compounds with sulfoxide and sulfone functional groups. This novel study offers valuable insights into the generation of secondary products and sheds light on the roles of overlayer metals and photon wavelength in the photodecontamination process of CWA.

Evaluation of the effect of dimethyl fumarate on human bone marrow-derived mesenchymal stem cells using bottom-up proteomics.

Mesenchymal stem cells (MSCs) have potential as a viable treatment option in the field of regenerative medicine, but MSC-based therapy needs to be more efficient. Preconditioning is a method to improve MSC-based therapy, and dimethyl fumarate (DMF) - an agent that can enhance the antioxidative capacity of cells - can be considered for preconditioning of MSCs. In this study, we treated bone marrow-derived MSCs with DMF and evaluated their proteome using bottom-up proteomics. The MSCs were exposed to 10 µM DMF for 24 h, followed by lysis with an SDS solution, digestion with trypsin using an s-trap column, and analysis using nanoLC-MS/MS, which identified 2262 proteins with confidence. Bioinformatic analysis of the identified proteins revealed 47 upregulated proteins and 81 downregulated proteins upon DMF treatment. Pathway enrichment analysis suggested a possible decrease in autophagy and a decrease in the activity of the TCA cycle, while indicating a potential increase in proliferation and antioxidant activity in DMF-treated MSCs compared to untreated MSCs. Our findings suggest that DMF can enhance the proliferation of MSCs and increase their stability, and that preconditioning could improve the therapeutic efficacy of MSCs for the treatment of regenerative diseases.

Identification of geographical origins of soybean pastes using headspace gas chromatography-mass spectrometry by selecting sample-descriptive components with an Incremental Association Markov Blanket.

The identification of geographical origins of soybean pastes using headspace gas chromatography-mass spectrometry was attempted in this study. Since soybean paste was odor-rich, 36 components were identified in the imported and domestic soybean samples. t-Test, variable importance in projection (VIP), and Incremental Association Markov Blanket (IAMB) were employed to select proper components that could effectively discriminate the two sample groups. The discrimination accuracies were below 87.3 % when all 36 components were fed for either LDA, k-NN, or SVM. When the five t-test-selected components or six VIP score-selected components were employed, the accuracies improved to 95.2-96.2 %. The IAMB selected three different components were 3-methylbutanal, 4-methylnonane, and 2,3-pentanedione, and the correlations among their peak areas were not significant. This suggests that these three components were independently relevant for the discrimination. The accuracy obtained using these three components was superior, 97.7 %, as undescriptive and/or redundant components for the discrimination were excluded.

Accurate determination of 11 representative phthalates and di(2-ethylhexyl) terephthalate in polyvinyl chloride using isotope dilution-gas chromatography/mass spectrometry.

Phthalates are mainly used as plasticizers in polyvinyl chloride (PVC). However, prolonged exposure to phthalates poses considerable risks to human health. Consequently, the utilization of phthalates in consumer products is subject to regulations, with a defined threshold of 0.1 %. In this study, we developed an accurate and simultaneous method for determination of 11 representative phthalates and a non-phthalate plasticizer (di(2-ethylhexyl) terephthalate, DEHT) in PVC as a higher-order reference method. Homogeneously prepared PVC samples, each containing approximately 0.1 % of the target plasticizer compounds, were analyzed using gas chromatography-mass spectrometry (GC-MS) with deuterium-labeled phthalates and DEHT. The developed method could effectively separate and quantify all target plasticizers without interference with each other and potential overlap between the isomeric forms of phthalates, di-isodecyl phthalate, and di-isononyl phthalate. The developed method has high-order metrological quality, exhibiting exceptional selectivity, accuracy, repeatability (≤ 2.17 %), reproducibility (≤ 2.16 %), and relative expanded uncertainty (≤ 5.6 %). This analytical method is thus suitable for accurately assessing the target plasticizer levels in PVC products for ensuring compliance with the established 0.1 % threshold. This method was successfully applied to quantify twelve distinct plasticizers in PVC products obtained from the Korean market, validating its effectiveness and reliability in real-world scenarios.

Size-exclusion chromatography for the characterization of urinary extracellular vesicles.

In recent years, extracellular vesicles (EVs) have gained attention for their potential as biomarkers for the early diagnosis and treatment of various diseases. Traditionally, EV isolation has relied exclusively on ultracentrifugation. However, alternative enrichment methods such as size-exclusion chromatography (SEC) and polyethylene glycol-based precipitation have been introduced. This study utilized SEC as a characterization tool to assess the efficiency of EV isolation. Urinary EVs isolated from human urine using centrifugation (40,000 × g) were analyzed using an SEC column with a pore size of 1000 Å, an inner diameter of 7.8 mm, and a length of 300 mm. The EVs were detected sequentially using UV (280 nm) and fluorescence (λex/em = 550 nm/565 nm); the EVs were observed at approximately 6 min, while the proteins were observed at approximately 12 min. The repeated centrifugation enrichment steps resulted in an increase in EV peaks and a decrease in protein peaks. SEC analysis of the enriched EV samples confirmed that a four-cycle repetition of centrifugation is necessary for successful EV enrichment and removal of non-EV proteins from 40 mL of human urine.

Potential applications of mesenchymal stem cells and their derived exosomes in regenerative medicine.

INTRODUCTION: Regenerative medicine involves the replacement of damaged cells, tissues, or organs to restore normal function. Mesenchymal stem cells (MSCs) and exosomes secreted by MSCs have unique advantages that make them a suitable candidate in the field of regenerative medicine. AREAS COVERED: This article provides a comprehensive overview of regenerative medicine, focusing on the use of MSCs and their exosomes as potential therapies for replacing damaged cells, tissues, or organs. This article discusses the distinct advantages of both MSCs and their secreted exosomes, including their immunomodulatory effects, lack of immunogenicity, and recruitment to damaged areas. While both MSCs and exosomes have these advantages, MSCs also have the unique ability to self-renew and differentiate. This article also assesses the current challenges associated with the application of MSCs and their secreted exosomes in therapy. We have reviewed proposed solutions for improving MSC or exosome therapy, including ex-vivo preconditioning strategies, genetic modification, and encapsulation. Literature search was conducted using Google Scholar and PubMed databases. EXPERT OPINION: Providing insight into the future development of MSC and exosome-based therapies and to encourage the scientific community to focus on the identified gaps, develop appropriate guidelines, and enhance the clinical application of these therapies.

A guide to mass spectrometric analysis of extracellular vesicle proteins for biomarker discovery.

Exosomes (small extracellular vesicles) in living organisms play an important role in processes such as cell proliferation or intercellular communication. Recently, exosomes have been extensively investigated for biomarker discoveries for various diseases. An important aspect of exosome analysis involves the development of enrichment methods that have been introduced for successful isolation of exosomes. These methods include ultracentrifugation, size exclusion chromatography, polyethylene glycol-based precipitation, immunoaffinity-based enrichment, ultrafiltration, and asymmetric flow field-flow fractionation among others. To confirm the presence of exosomes, various characterization methods have been utilized such as Western blot analysis, atomic force microscopy, electron microscopy, optical methods, zeta potential, visual inspection, and mass spectrometry. Recent advances in high-resolution separations, high-performance mass spectrometry and comprehensive proteome databases have all contributed to the successful analysis of exosomes from patient samples. Herein we review various exosome enrichment methods, characterization methods, and recent trends of exosome investigations using mass spectrometry-based approaches for biomarker discovery.

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.

Controlled growth of redox polymer network on single enzyme molecule for stable and sensitive enzyme electrode.

The electrochemical applications of enzymes are often hampered by poor enzyme stability and low electron conductivity. In this work, a novel enzyme nanogel based on atom transfer radical polymerization (ATRP) has been developed for highly sensitive detection of glucose based on ferrocene (Fc) embedded in crosslinked polymer network nanogel. Enzyme surfaces are successively modified with Br initiator, and then in situ atom transfer radical polymerization (ATRP) was performed to build up crosslinked polyacrylamide network. The resulting single enzyme nanogel (ATRP-SEG) is uniform in size fairly. ATRP-SEG reveals bi-phasic inactivation, and the half-life of stable ATRP-SEG after 18-day incubation at 50 °C is 47 days, which is 197 times longer than that of free Gox (5.7 h). By introducing a ferrocene (Fc) containing redox polymer, poly(acrylamide-co-vinylferrocene), the half-life of Fc-ATRP-SEG after 18-day incubation at 50 °C is 49 days. Fc-ATRP-SEG is used for preparation of glucose-sensing electrode, and the sensitivity of Fc-ATRP-SEG electrode is 111 µA cm-2 mM-1, which is 366 and 1270 times higher than those of free GOx (0.303 µA cm-2 mM-1) and ATRP-SEG (0.0874 µA cm-2 mM-1), respectively. Fc-ATRP-SEG electrode maintained 90% of initial current density under 4 °C storage condition and repetitive usages every day for 7 days. Even the electrode repeatedly used in continuous harsh condition (250 rpm, room temperature), the current density maintained 96% after 12 h incubation at operational condition.

Detection of multiply charged protein ions using matrix-assisted laser desorption/ionization mass spectrometry and a force-dried droplet method with a 2-nitrophloroglucinol matrix.

Conventional dried droplet (DD) methods show poor reproducibility in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) due to the frequent induction of a heterogeneous sample distribution. Recently, a forced dried droplet (FDD) sample preparation method was introduced to form homogeneous samples; this method improves the reproducibility of MALDI-MS analysis and generates highly multiply charged ions compared to DD methods. The FDD method utilizes secondary nucleation to generate a homogeneous sample distribution by applying an external force such as fluid shear stress by stirring the sample using a micropipette tip. In this study, a 2-nitrophloroglucinol (2-NPG) matrix was used for the DD and FDD sample preparation methods, and the charge state and homogeneity were compared by detecting multiply charged ions of proteins including cytochrome c, myoglobin, and immunoglobulin G (IgG) and measuring the relative standard deviation (RSD). FDD with a 2-NPG matrix produced a more homogeneous sample distribution and higher charge state ions than the DD method. FDD with a 2-NPG matrix was applied in MALDI-MS analysis of IgG fragments obtained from sequential reduction of IgG. In addition, FDD with intentional scratching of the MALDI plate by rotating a micropipette tip was found to provide similar or better reproducibility, higher charge state ions, and more uniformly distributed sample morphology compared to FDD without scratching.

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.

Comparison of ultraviolet and refractive index detections in the HPLC analysis of sugars.

Refractive index (RI) detection is the standard approach for quantitatively detecting sugars via high-performance liquid chromatography (HPLC), while ultraviolet (UV) absorbance detection is the most commonly used detection method for general HPLC analysis. We compared the two detection approaches of UV and RI in the HPLC analysis of small sugars to investigate whether UV detection could be an alternative method to RI detection. UV detection was performed using a photodiode array scanning from 190 to 400 nm. We obtained comparable limit of detection (LOD) results for RI and UV detection in the HPLC analysis of monosaccharides, while HPLC-RI provided better LOD results than HPLC-UV in disaccharide analysis. Both HPLC-RI and HPLC-UV methods were applied to analyze a real honey sample, and similar results were obtained in terms of precision and recovery. The study conclusively shows that the UV-based HPLC analysis of sugars offers a sufficient alternative to RI-based HPLC analysis.

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.

Characterization of RDX and HMX explosive adduct ions using ESI FT-ICR MS.

Investigation of two common explosives such as cyclonite (RDX) and cyclotetramethylenetetranitramine (HMX) using a mass spectrometer with ultrahigh resolution and accuracy has not been comprehensively performed. Here, ultrahigh mass accuracy 15-T Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) spectra were utilized to comprehensively characterize the adduct ions of RDX and HMX. Two different ionization sources such as a conventional electrospray ionization (ESI) source and a chip-based static nano-ESI source were used to investigate the adduct ions of RDX and HMX. The ESI-MS analyses of two explosives in negative ion mode provide some adduct ions of RDX and HMX even without prior addition of their corresponding anions. A total of six types of adduct ion were characterized: [M + Cl]- , [M + HCOO]- , [M + NO2 ]- , [M + CH3 COO]- , [M + NO3 ]- , and [M + C3 H5 O3 ]- , where M is either RDX or HMX. The ultrahigh accuracy of the 15-T FT-ICR MS was utilized to distinguish two closely spaced peaks representing the monoisotopic [M + NO2 ]- and second isotopic [M + HCOO]- ions, thereby enabling the discovery of a [M + NO2 ]- adduct ion in the ESI analysis of RDX or HMX. [M + NO2 ]- and [M + CH3 COO]- adduct ions were only observed when using a static nano-ESI source. It is the first report explaining the discovery of [M + NO2 ]- adduct ion in the ESI-MS analyses of RDX and HMX.

Development of candidate reference method for accurate determination of four polycyclic aromatic hydrocarbons in olive oil via gas chromatography/high-resolution mass spectrometry using 13C-labeled internal standards.

We developed an isotope-dilution gas chromatography/high-resolution mass spectrometry (ID-GC/HRMS) method for the accurate determination of four polycyclic aromatic hydrocarbons (PAHs) in olive oil. The clean-up steps were optimized to sufficiently remove co-extracted oil matrix using the EZ-POP NP dual-layer and NH2 solid-phase extraction (SPE) cartridges. However, the cleaned sample still contained some matrix residues, which caused a bias. When 13C-labeled PAHs were used as the internal standards instead of deuterated PAHs, the recovery results improved in both low- and high-resolution MS conditions. Furthermore, the HRMS analysis facilitated to obtain more accurate results. The accuracy and precision of the optimized ID-GC/HRMS method were validated using PAH-fortified (0.5, 3, and 6 µg/kg) olive oil. The recoveries and relative standard deviations obtained for all the PAHs/levels were 97.5-102% and ~1%, respectively. Measurement uncertainties were generally within 5% (with a 95% confidence level).

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.