Significant Isotope Effects from the Nonadiabatic Couplings in the Cl(2P) + HD(v = 0, j = 0) Reaction.

The impact of non-Born-Oppenheimer couplings on the isotopic effects in the reaction of the Cl(2P) atom with the HD (v = 0, j = 0) molecule is investigated with our recently developed nonadiabatic time-independent quantum scattering methods, where the full open-shell characteristics are included in the six-state model, and also with the recently developed two-state model solving by time-independent methods, where part of the open-shell characteristic is included. The same reaction is also calculated with the simple adiabatic model using the lowest adiabatic potential energy surface. Compared with the results from different models, it is found that the reactivity of the Cl + HD → HCl + D channel is significantly overestimated in the adiabatic model. In contrast, the reactivity of the other channel agrees well with the nonadiabatic models. This is due to the van der Waals well in the reactant channel being changed a lot by including the nonadiabatic couplings. These quantum dynamics calculations suggest that sometimes the adiabatic model should be used with caution; otherwise, it may result in significant deviations for some reactions.

Rapid identification of bacterial mixtures in urine using MALDI-TOF MS-based algorithm profiling coupled with magnetic enrichment.

Urinary tract infections (UTIs) are a severe public health problem caused by mono- or poly-bacteria. Culture-based methods are routinely used for the diagnosis of UTIs in clinical practice, but those are time consuming. Rapid and unambiguous identification of each pathogen in UTIs can have a significant impact on timely diagnoses and precise treatment. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an alternative method for the identification of pathogens in clinical laboratories. However, a certain number of pure bacteria are required for MALDI-TOF MS analysis. Here, we explored a strategy combining magnetic enrichment and MALDI-TOF MS for the rapid identification of pathogenic bacterial mixtures in urine. Fragment crystallizable mannose-binding lectin-modified Fe3O4 (Fc-MBL@Fe3O4) was used for rapid enrichment and the individual-peak-based similarity model as the analytical tool. Within 30 min, a mixture of the four most prevalent UTI-causing bacteria, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa, was successfully identified using this method. This rapid MALDI-TOF MS-based strategy has potential applications in the clinical identification of UTI pathogens.

Fc-MBL-modified Fe3O4 magnetic bead enrichment and fixation in Gram stain for rapid detection of low-concentration bacteria.

Functional bacterial enrichment magnetic beads (Fe3O4@SiO2@Fc-MBL) and Gram staining were combined for the fast diagnosis of infecting bacteria in meningitis. Fe3O4@SiO2@Fc-MBL has excellent microbial binding ability and can be used for bacterial enrichment from cerebrospinal fluid (CSF). The enriched bacteria are recognized by Gram stain at very low concentrations (10 CFU·mL-1). The feasibility of this method was verified by five common bacteria in meningitis infection (Gram-positive: Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus capitis; Gram-negative: Klebsiella pneumoniae and Escherichia coli). The extraction efficiency of Fc-MBL-modified Fe3O4 magnetic beads was approximately 90% in artificial CSF for the selected bacteria, with the exception of E. coli (~ 60%). The bacteria were successfully recognized by Gram staining and microscopic observation. Fe3O4@SiO2@Fc-MBL acts by capturing and fixing the bacteria in a magnetic field throughout the experiment. Compared with traditional CSF Gram staining, this new method avoids interference by inflammatory cells and red blood cells during microscopic examination. Furthermore, the sensitivity of this method is much better than the centrifugation smear method. The whole process can be accomplished within 30 min. This novel method may have potential as a clinical tool for analysis of bacteria in the CSF.

Yo-Yo Dieting Delays Male Drosophila melanogaster Aging Through Enhanced Mitochondrial Function, Relative to Sustained High-Calorie Diet Feeding.

Weight regain subsequent to weight reduction resulting from dietary interventions represents a prevalent phenomenon recognized as "Yo-yo dieting." However, the impact of prolonged Yo-yo dieting on health, especially in relation to the aging process, remains poorly understood. This study aimed to investigate the influence of Yo-yo dieting on the aging process in male Drosophila melanogaster that have been exposed to a high-calorie (HC) diet. Fruit flies were fed with either a consistent HC diet or an alternating regimen of HC and low-calorie diets every 3 days (referred to as "Yo-yo dieting") for a total of 24 days. Biochemical assays were utilized to quantify levels of oxidative stress and activities of the mitochondrial respiratory chain complexes. The frozen section staining method was employed to assess the presence of lipid droplets, reactive oxygen species, cellular viability, and mitochondrial abundance in tissues. Additionally, we examined the expression of key regulators involved in mitochondrial dynamics and biogenic signaling pathways. Yo-yo dieting resulted in an extension of the fruit flies' lifespan, concomitant with reduced body weight, decreased body protein content, and lower triglyceride levels compared to continuous a HC diet feeding. Furthermore, Yo-yo dieting ameliorated impairments in motility and intestinal barrier function. Importantly, it improved mitochondrial function and upregulated the expression of essential mitochondrial fusion proteins, namely mitofusin 1 and mitofusin 2, optic atrophy 1, and peroxisome proliferator-activated receptor-γ coactivator-1α. Therefore, the practice of Yo-yo dieting extends the lifespan of fruit flies by modulating mitochondrial dynamics and the associated biogenic signaling pathways.

Simple and Rapid Discrimination of Methicillin-Resistant Staphylococcus aureus Based on Gram Staining and Machine Vision.

Methicillin-resistant Staphylococcus aureus (MRSA) is a clinical threat with high morbidity and mortality. Here, we describe a new simple, rapid identification method for MRSA using oxacillin sodium salt, a cell wall synthesis inhibitor, combined with Gram staining and machine vision (MV) analysis. Gram staining classifies bacteria as positive (purple) or negative (pink) according to the cell wall structure and chemical composition. In the presence of oxacillin, the integrity of the cell wall for methicillin-susceptible S. aureus (MSSA) was destroyed immediately and appeared Gram negative. In contrast, MRSA was relatively stable and appeared Gram positive. This color change can be detected by MV. The feasibility of this method was demonstrated in 150 images of the staining results for 50 clinical S. aureus strains. Based on effective feature extraction and machine learning, the accuracies of the linear linear discriminant analysis (LDA) model and nonlinear artificial neural network (ANN) model for MRSA identification were 96.7% and 97.3%, respectively. Combined with MV analysis, this simple strategy improved the detection efficiency and significantly shortened the time needed to detect antibiotic resistance. The whole process can be completed within 1 h. Unlike the traditional antibiotic susceptibility test, overnight incubation is avoided. This new strategy could be used for other bacteria and represents a new rapid method for detection of clinical antibiotic resistance. IMPORTANCE Oxacillin sodium salt destroys the integrity of the cell wall of MSSA immediately, appearing Gram negative, whereas MRSA is relatively stable and still appears Gram positive. This color change can be detected by microscopic examination and MV analysis. This new strategy has significantly reduced the time to detect resistance. The results show that using oxacillin sodium salt combined with Gram staining and MV analysis is a new, simple and rapid method for identification of MRSA.

Mechanisms of JinHong Formula on treating sepsis explored by randomized controlled trial combined with network pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: JinHong Formula (JHF) was derived from the famous Rhubarb and Moutan Decoction which was prescribed for appendicitis. It was originally recorded in the classic of "Jingui Yaolve" written by Zhang Zhongjing. It is a kind of traditional Chinese medicine, widely used in the treatment of inflammation. However, the clinical effect of JHF for sepsis and its comprehensive mechanism in sepsis remained largely unknown. RESEARCH PURPOSE: The aim of our study was to evaluate the clinical effect of JHF in the treatment of sepsis, and to explore its mechanism from the perspective of network pharmacology. RESEARCH METHODS: The single-center randomized clinical trial was conducted to assess the effect of JHF in the treatment of sepsis. Additionally, we used the Chinese herbal medicine pharmacology database and analysis platform to identify the active components and therapeutic target of JHF. Numerous well-known disease target databases have been used to screen therapeutic target proteins for sepsis. Furthermore, we have established a Protein-Protein Interaction (PPI) network and carried out Gene Onotology/Kyoto Encyclopedia of Genes and Genomes (GO/KEGG) enrichment analysis. In order to conclude which active compounds from JHF may be responsible for signaling pathway, we performed network analysis. RESEARCH RESULTS: The study included 114 patients. By comparing participants with and without JHF, the results suggested that JHF significantly reduced all-cause mortality on 28 and 60 days after intervention, and improved Sequential Organ Failure Assessment (SOFA) on 7th day after intervention as well as. JHF had an effect of anti-inflammatories and antioxidants (SOD). By using network pharmacological analysis, we identified 72 active components and 426 target genes of JHF, and successfully constructed a "JHF-compound target-sepsis" network. 116 mentioned targets revealed by GO/KEGG enrichment analysis played a significant role in the inflammatory reaction and immunoregulation via interleukin-17 (IL-17) and tumor necrosis factor (TNF) signaling pathway. Moreover, the analysis of "pathway target-active component" revealed that Sennidin A, Rheidin A, Rheidin B, Rheidin C, (E)-4-Phenyl-3-Buten-2-One, Osmanthuside H, Esculetin, and Caffeicacid were responsible for IL-17, TNF signaling pathways. CONCLUSION: JHF contains potential active substance of anti-inflammatory and antioxidant. These active compounds may come into play through IL-17 and TNF signaling pathways. For sepsis, JHF may be a promising and effective treatment strategy.

Protocol for bacterial typing using Fourier transform infrared spectroscopy.

The Fourier transform infrared (FT-IR) signals obtained from bacterial samples are specific and reproducible, making FT-IR an efficient tool for bacterial typing at a subspecies level. However, the typing accuracy could be affected by many factors, including sample preparation and spectral acquisition. Here, we present a unified protocol for bacterial typing based on FT-IR spectroscopy. We describe sample preparation from bacterial culture and FT-IR spectrum collection. We then detail FT-IR spectrum preprocessing and multivariate analysis of spectral data for bacterial typing.

A retrospective study of Reyanning mixture in elderly patients infected with SARS-CoV-2 Omicron variant.

Objective: Reyanning mixture has been demonstrated to be effective in treating infected patients during the outbreak pandemic of SARS-CoV-2 Omicron variant of Coronavirus disease 2019 (COVID-19) in Shanghai 2022. The aim of this study is to further investigate the role of Reyanning mixture specifically in the treatment of elderly patients. Methods: This study enrolled 1,102 elderly patients who were infected with SARS-CoV-2 Omicron variant. Of these, 291 patients received Reyanning mixture in conjunction with conventional Western medicine treatment were assigned to the treatment group, while 811 patients only received conventional Western medicine treatment were assigned to the control group. Clinical parameters including hospitalization duration, viral shedding time, and Cycle Threshold (Ct) values of novel coronavirus nucleic acid tests, as well as adverse events were recorded and analyzed in both groups. Results: There was no significant difference in baseline characteristics between two groups. In comparison to the control group, the treatment group demonstrated a substantial difference in hospitalization duration (median: 8 days vs. 10 days, HR: 0.638, 95% CI: 0.558-0.731, p < 0.001). The treatment group also showed a significantly shorter viral shedding time compared to the control group (median: 7 days vs. 8 days, HR: 0.754, 95% CI: 0.659-0.863, p < 0.001). Multivariate Cox proportional-hazards model analysis indicated that the use of Reyanning mixture was closely associated with a reduction in hospitalization duration (HR: 1.562, 95% CI: 1.364-1.789, p < 0.001) and viral shedding time (HR: 1.335, 95% CI: 1.166-1.528, p < 0.001). In addition, during the treatment process, no serious adverse event occurred in either group. Conclusion: The improvement of clinical parameters in the treatment group indicate a promising therapeutic benefit of Reyanning mixture for elderly patients infected with SARS-CoV-2 Omicron variant in the present study. Further investigations are required to validate this finding by examining the underlying mechanism and function of Reyanning mixture.

A versatile biomimetic multienzyme cascade nanoplatform based on boronic acid-modified metal-organic framework for colorimetric biosensing.

The combination of bio- and chemo-catalysts for sequential cascades has received considerable attention in analytical fields because of the regulable catalytic efficiency and selectivity under various physiological conditions. In this paper, a versatile multienzyme cascade nanoplatform with excellent activity for biosensing is demonstrated by combining metal-organic framework (MOF)-based nanozyme with natural enzymes. A boronic acid-modified MOF, MIL-100(Fe)-BA, was obtained via a microwave-assisted metal-ligand-fragment co-assembly strategy. On the one hand, MIL-100(Fe)-BA could serve as a nanozyme with dual oxidase/peroxidase bioactivity to detect glutathione and ascorbic acid with a detection limit of 0.12 µM and 0.09 µM, respectively. On the other hand, the hierarchically porous MIL-100(Fe)-BA possesses adequate recognition sites for immobilizing enzymes with acceptable protein leakage, enabling it to act like a scaffold for the fixation of a single enzyme (sarcosine oxidase) or bi-enzymes (acetylcholinesterase/choline oxidase) and guide a multienzyme cascade reaction system with high efficiency. The cascade nanoplatform has merits of both artificial nanozymes and natural enzymes, providing satisfactory sarcosine/acetylcholine sensing ability with detection limits of 0.26 µM and 1.18 µM. The developed catalytic system not only expands the application of nanozymes in tandem enzymatic bio-catalysis, but provides a facile and efficient multienzyme cascade nanoplatform for biosensing and other applications.

Progress in infrared spectroscopy as an efficient tool for predicting protein secondary structure.

Infrared (IR) spectroscopy is a highly sensitive technique that provides complete information on chemical compositions. The IR spectra of proteins or peptides give rise to nine characteristic IR absorption bands. The amide I bands are the most prominent and sensitive vibrational bands and widely used to predict protein secondary structures. The interference of H2O absorbance is the greatest challenge for IR protein secondary structure prediction. Much effort has been made to reduce/eliminate the interference of H2O, simplify operation steps, and increase prediction accuracy. Progress in sampling and equipment has rendered the Fourier transform infrared (FTIR) technique suitable for determining the protein secondary structure in broader concentration ranges, greatly simplifying the operating steps. This review highlights the recent progress in sample preparation, data analysis, and equipment development of FTIR in A/T mode, with a focus on recent applications of FTIR spectroscopy in the prediction of protein secondary structure. This review also provides a brief introduction of the progress in ATR-FTIR for predicting protein secondary structure and discusses some combined IR methods, such as AFM-based IR spectroscopy, that are used to analyze protein structural dynamics and protein aggregation.

Highly efficient synergistic biocatalysis driven by stably loaded enzymes within hierarchically porous iron/cobalt metal-organic framework via biomimetic mineralization.

The integration of multimodal chemo-/bio-catalysis for efficient cascade reactions has long provided broad prospects in the field of biotechnology for ages. In this work, we describe the synthesis of a biomimetic multienzyme hybrid with hierarchically porous structure and outstanding catalytic activity via in situ encapsulation of natural enzymes in an iron-cobalt bimetallic metal-organic framework (Fe/Co-MOF, FCM). The combination of a single enzyme (glucose oxidase) or dual enzyme (ß-galactosidase and glucose oxidase) with FCM resulted in remarkable synergistic biocatalysis ability; in contrast to simple biocatalyst mixtures in solution, the prepared multienzyme hybrid resulted in 3.2-fold and 2.1-fold improvements in activity for tandem reactions, respectively. The reinforced cascade bioactivity of the multienzyme hybrid benefitted from the synergistic effect between iron/cobalt in the FCM nanozyme, the opened substrate channel between enzymes/nanozymes, and the beneficial effect provided by the hierarchical MOF pores. The enlarged pores not only provided adequate space for immobilized proteins to diffuse and reorientate in FCM with low surface energy, but also reduced the intrinsic mass transfer obstacle to increase the diffusional efficiency of reactants/intermediates. In addition, on account of the shielding effect provided by FCM, the multienzyme hybrid exhibited enhanced tolerance towards severe circumstances and excellent reusability and has been successfully applied in small molecule detection, such as glucose and lactose. The current study highlights the superiority of synergistic bioreactors integrated with the MOF nanozyme and natural enzymes, suggesting great potential for applications in sustainable biomimetic catalysis.

Efficient classification of Escherichia coli and Shigella using FT-IR spectroscopy and multivariate analysis.

Accurate and effective discrimination of E. coli and Shigella is an important clinical issue, and there are many limitations in traditional methods of analysis. FT-IR shows great potential in the classification of bacteria with high specificity and low cost. In this study, we evaluated the efficiency of this technique when combined with multivariate analysis for rapid classification of E. coli and Shigella, which is difficult using traditional analytical methods. Machine learning and statistical tools were employed in combination with FT-IR to classify 14 E. coli and 9 Shigella strains. The classification accuracies for select E. coli and Shigella strains from blood agar were 0.7826, 0.8696, and 0.9565 at the genus, species, and strain levels, respectively. In addition, we used the FT-IR data of select strains from three different culture media for cross-validation, yielding an accuracy of 0.3681 at the strain level. These results indicate that the bacterial culture conditions have a significant impact on the FT-IR patterns. Based on this, an improved strategy for training an ensemble classifier model considering bacterial culture factors was constructed, resulting in almost perfect separation with an accuracy of 0.9394 for strain-level classification. These results show the potential of FT-IR combined with multivariate analysis for more reliable bacterial classification.

Protein FT-IR amide bands are beneficial to bacterial typing.

Bacterial FT-IR signals are extremely specific and highly reproducible, making FT-IR an efficient tool for bacterial typing at the subspecies level. The polysaccharide and nucleic acid FT-IR regions (1200-900 cm-1) are recommended as a precise and reproducible pattern for bacterial typing. However, proteins are the major macromolecules present in bacteria, and the FT-IR spectral region of proteins (1800-1300 cm-1) is conceivably an important factor in bacterial typing. In this study, we investigated the influence of water on bacterial protein amide bands by comparing spectra obtained with and without FT-IR system dehydration. Eight Escherichia coli, ten Klebsiella pneumoniae, and eleven Staphylococcus aureus strains were typed by FT-IR under different conditions in a blinded experimental setup. Hierarchical clustering analysis (HCA) showed that, when protein signals were included (1800-900 cm-1), the typing accuracies for select E. coli, K. pn and S. aureus strains without system dehydration were 50%, 30% and 18.2%, respectively. However, the accuracies greatly improved to 100%, 90% and 90.9% when the FT-IR system was dehydrated. These results indicate that the FT-IR signals of protein amide bands are beneficial for bacterial typing.

Deficiency of migration inhibitory factor influences the gut microbiota of C57BL/6 mice infected with Plasmodium berghei ANKA.

Cerebral malaria (CM), as one of the most common complications in severe malaria, has threatened millions of individuals' neurological health and even their lives. Macrophage migration inhibitory factor (MIF), a pleiotropic proinflammatory factor in humans, seems to be a risk factor for death in patients with CM, but its functional mechanism remains unclear. To verify whether affecting the intestinal microbes of the host was one of the mechanisms by which MIF regulates CM, C57BL/6 mice, including WT + PbA, MIF-KO + PbA and their uninfected controls, were sent for 16S rRNA-based sequencing targeting the V4 region of the intestinal microbiota through the Illumina MiSeq platform. The results showed that OTU clustering, alpha and beta diversity in the four groups involved had evident variation. The relative abundance at different taxonomic levels, especially the dominant intestinal flora, was obviously changed. The LEfSe analysis screened out several biomarkers, including significantly reduced Ligilactobacillus (Lactobacillus murinus) in WPbA mice compared to the WT group and Akkermansia (Akkermansia_muciniphila) in KPbA mice compared to the WPbA group. For MIF KO groups, mice infected with PbA or uninfected showed significant enrichment of producers of short-chain fatty acids, including Dubosiella and Faecalibaculum (Faecalibaculum rodentium) in KPbA, and Lachnospiraceae_NK4A136_group and Firmicutes_bacterium_M10-2 in KO. This study not only further proved the gut microbiota changes in C57BL/6 mice caused by PbA infection, but also found that MIF deletion directly affected the changes in the gut microbiota of C57BL/6 mice before and after PbA infection. This finding reveals a potential mechanism by which MIF regulates CM. Combining MIF with potential microbial biomarkers will provide a promising idea to develop combined drugs for improving CM in the future.

Rapid identification of bacteria directly from blood cultures by Co-magnetic bead enrichment and MALDI-TOF MS profiling.

Direct identification of bacteria in blood cultures using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is interfered with by a variety of non-bacterial proteins derived from blood cells and culture media. Thus, appropriate pre-treatments are needed for successful identification. Here, the bacteria in blood culture bottles were enriched using co-magnetic beads and processed for MALDI-TOF MS profiling. In this strategy, the Fc-containing mannose-binding lectin-coated Fe3O4 (Fc-MBL@Fe3O4) is incorporated with human IgG-coated Fe3O4 (IgG@Fe3O4) to form co-magnetic beads, which can recognize both Gram-positive and Gram-negative bacteria. Compared to single magnetic beads Fc-MBL@Fe3O4 or IgG@Fe3O4, co-magnetic beads resulted in better bacterial capture efficiency and, therefore, could decrease the false-negative results. Our proposed strategy is much more suitable for enrichment of clinically unknown bacteria from blood culture bottles for MALDI-TOF MS database identification.

Effective discrimination of Yersinia pestis and Yersinia pseudotuberculosis by MALDI-TOF MS using multivariate analysis.

Separating Yersinia pseudotuberculosis and Yersinia pestis is an important issue in plague diagnosis but can be extremely difficult because of the high similarity between the two species. MALDI-TOF MS has grown as a diagnostic tool with great potential in bacterial identification. Its application in this field is largely enhanced by multivariate analysis, especially in extracting subtle spectral differences. In this study, we built a complete MALDI-TOF MS data pipeline and found a Y. pestis-specific biomarker at 3063 Da closely related to Y. pestis plasminogen activation factor. Based on this, we achieved almost perfect separation between Y. pseudotuberculosis and Y. pestis (AUC = 0.999) using a supervised linear discriminant analysis (LDA) model. This is significantly better than the conventionally applied unsupervised spectral similarity comparison methods, such as hierarchical clustering analysis (HCA), which gave a separation accuracy of 75.0%. This new computing method paves the way for automatic differentiation between the two highly similar bacterial species with high separation accuracy.

Therapeutic potential of endogenous hydrogen sulfide inhibition in breast cancer (Review).

Hydrogen sulfide (H2S), the third gas signal molecule, is associated with the modulation of various physiological and pathological processes. Recent studies have reevealed that endogenous H2S may promote proliferation, induce angiogenesis and inhibit apoptosis, thereby stimulating oncogenesis. Conversely, decreased endogenous H2S release suppresses growth of various tumors including breast cancer. This observation suggests an alternative tumor therapy strategy by inhibiting H2S­producing enzymes to reduce the release of endogenous H2S. Breast cancer is the most common type of cancer in women. Due to the lack of approved targeted therapy, its recurrence and metastasis still affect its clinical treatment. In recent years, significant progress has been made in the control of breast cancer by using inhibitors on H2S­producing enzymes. This review summarized the roles of endogenous H2S­producing enzymes in breast cancer and the effects of the enzyme inhibitors on anticancer and anti­metastasis, with the aim of providing new insights for the treatment of breast cancer.

Releasing bacteria from functional magnetic beads is beneficial to MALDI-TOF MS based identification.

Bacterial infections are the key cause of morbidity and mortality worldwide. Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS)-based bacterial identification has been widely accepted in the clinic. Functional material, such as rabbit immunoglobulin G-modified Fe3O4 (IgG@Fe3O4) and fragment crystallizable mannose binding lectin-modified Fe3O4 (FcMBL@Fe3O4), is used to capture bacteria from biological samples for MALDI-TOF MS identification, and the bacteria MS signals are usually obtained by directly smearing enriched bacteria on a MALDI target with MALDI matrix solution. However, the accuracy of identification based on MALDI-TOF MS may be affected by the presence of functional molecules, especially proteins, resulting in errors in the comparison with the standard bacterial spectra in the database. Moreover, the long-term presence of the magnetic beads on the MALDI-TOF target may reduce the instrument service life. In this study, we constructed FcMBL@Fe3O4 and used it to capture bacteria from both aqueous solution and bovine blood, and the bacterial identification accuracy based on different target preparation methods was compared. In the presence of Ca2+, the similarity scores for bacteria identified with FcMBL@Fe3O4 were ~88% and ~82% for Staphylococcus. aureus and Escherichia coli, respectively. In the presence of ethylenediaminetetraacetic acid (EDTA), bacteria separate from FcMBL@Fe3O4, resulting in similarity scores of ~96% and ~92% for S. aureus and E. coli, respectively. These results indicate that the functional proteins on the surface of nanoparticles affect the accuracy of identification accuracy based on the MALDI-TOF MS database. Thus, the release of bacteria from the functional material could increase the identification accuracy and be beneficial for maintaining the instrument.

The strategy for correcting interference from water in Fourier transform infrared spectrum based bacterial typing.

Accurate and effective identification and typing of microorganisms is important in epidemiological surveillance. Fourier transform infrared (FTIR) spectroscopy is a promising bacterial typing method based on extracting the infrared spectrum signal-related biochemical features of intact microbiological cells. Unfortunately, the FTIR signals of bacteria are disturbed by many factors, especially the unavoidable absorbance of H2O, and many studies have focused only on the internal biochemical information. In this study, the interference from water was analyzed and verified by experimental data. The infrared absorbance of H2O overlapped with the protein (1200-1800 cm-1) and lipid regions (2800-3700 cm-1), but had little impact on the polysaccharide and nucleic acid region (900-1200 cm-1). The elimination of the protein and lipid region markedly decreased the interference of H2O and increased the typing accuracy. The results indicate that the polysaccharide and nucleic acid region (900-1200 cm-1) is the only credible region for bacterial typing, and typing based on this region not only reduces the size of the data analysis, but results in more reliable typing results.

Microfluidic Raman biochip detection of exosomes: a promising tool for prostate cancer diagnosis.

Tumor-derived exosomes, which contain RNA, DNA, and proteins, are a potentially rich non-invasive source of biomarkers. However, no efficient isolation or detection methods are yet available. Here, we developed a microfluidic Raman biochip designed to isolate and analyze exosomes in situ. Anti-CD63 magnetic nanoparticles were used to enrich exosomes through mixing channels of a staggered triangular pillar array. EpCAM-functionalized Raman-active polymeric nanomaterials (Raman beads) allow rapid analysis of exosome samples within 1 h, with a quantitative signal at 2230 cm-1. The limit of detection of this biochip approaches 1.6 × 102 particles per mL with 20 µL samples. The newly developed biochip assay was successfully applied in the determination of exosomes from clinical serum samples. Thus, this novel device may have potential as a clinical exosome analysis tool for prostate cancer.