SnO2-xNx based tpod nanostructure for SARS-CoV2 spike protein detection.

The worldwide spreading of severe acute respiratory syndrome SARS-CoV2 pandemic, a massive setback to every human being. In response to strategies actions against Covid-19 spreading many detection, prevention, and post-measures are being studied in large capacities. Association of SARS-CoV2 with ACE2 is well acknowledged and used for developing point-of-care detection kits. Recently, cases and studies have surfaced showing relation of ACE I/D polymorphism with spreading of SARS-CoV2 and highlighted a slip section towards detection and these studies show specificity with older males, high diabetes, and hypertension. To address the raised concern, we report synthesis of unique SnO2-xNx tpod nanostructure, showing affirmative attachment to both ACE1 and ACE2 efficiently. The attachment is examined in different ratios and studied with µ-Raman spectroscopy. The tpod nanostructure has served with its signature raman signals and used as probe for detection of SARS-CoV2 spike protein (S1). The linearity response for tpod raman signal at 630.4 cm-1 shows R2 0.9705, comparatively peak 1219.13 cm-1 show R2 0.9865 and calculated limit of detection of 35 nM.

Recent advances in nanomaterials-based optical sensors for detection of various biomarkers (inorganic species, organic and biomolecules).

This review briefly emphasizes the different detection approaches (electrochemical sensors, chemiluminescence, surface-enhanced Raman scattering), functional nanostructure materials (quantum dots, metal nanoparticles, metal nanoclusters, magnetic nanomaterials, metal oxide nanoparticles, polymer-based nanomaterials, and carbonaceous nanomaterials) and detection mechanisms. Furthermore, the emphasis of this review is on the integration of functional nanomaterials with optical spectroscopic techniques for the identification of various biomarkers (nucleic acids, glucose, uric acid, oxytocin, dopamine, ascorbic acid, bilirubin, spermine, serotonin, thiocyanate, Pb2+ , Cu2+ , Hg2+ , F- , peptides), and cancer biomarkers (mucin 1, prostate specific antigen, carcinoembryonic antigen, CA15-3, human epidermal growth factor receptor 2, C-reactive protein, and interleukin-6). Analytical characteristics of nanomaterials-based optical sensors are summarized in the tables, providing the insights of nanomaterials-based optical sensors for biomarkers detection. Finally, the opportunities and challenges of nanomaterials-based optical analytical approaches for the detection of various biomarkers (inorganic, organic, biomolecules, peptides and proteins) are discussed.

Correction: Progress of electrospray ionization and rapid evaporative ionization mass spectrometric techniques for the broad-range identification of microorganisms.

Correction for 'Progress of electrospray ionization and rapid evaporative ionization mass spectrometric techniques for the broad-range identification of microorganisms' by Suresh Kumar Kailasa et al., Analyst, 2019, 144, 1073-1103, DOI: 10.1039/C8AN02034E.

Photoluminescent hydrophilic cyclodextrin-stabilized cysteine-protected copper nanoclusters for detecting lysozyme.

Lysozyme (LYZ) sensors have attracted increased attention because rapid and sensitive detection of LYZ is highly desirable for various diseases associated with humans. In this research, we designed L-cysteine-protected ultra small photoluminescent (PL) copper nanoclusters (CuNCs) conjugated with ß-cyclodextrin (ß-CD) for rapid detection of LYZ in human serum samples at room temperature. The proposed ß-CD-CuNCs exhibited excellent water solubility, ultrafine size, good dispersion, bright photoluminescence, and good photostability. The ß-CD-CuNCs exhibit an excitation and emission maximum at 370 nm and 492 nm, respectively, with an absolute quantum yield (QY) of 54.6%. ß-CD-CuNCs showed a fluorescence lifetime of 12.7 ns. The addition of LYZ would result in PL quenching from ß-CD-CuNCs. The lowest detectable LYZ concentration was 50 nM for the naked eye and the limit of detection (LOD) and limit of quantification (LOQ) were 0.36 nM and 1.21 nM, respectively, by emission measurement observed in the LYZ concentration range from 30 to 100 nM. It is important to note that the PL ß-CD-CuNC strategy possessed great selectivity toward LYZ relative to other biomolecules. The proposed nanosensor was efficiently applied to determine the LYZ level in human serum sample average recoveries from 96.15 to 104.05% and relative standard deviation (RSD) values lower than 3.0%. Moreover, the proposed sensing system showed many advantages, including high speed, high sensitivity, high selectivity, low cost, and simple preparation.

Progress of electrospray ionization and rapid evaporative ionization mass spectrometric techniques for the broad-range identification of microorganisms.

Several non-culture molecular (multiplex polymerase chain reaction assays, DNA microarrays, massive parallel DNA sequencing, in situ hybridization, microbiome profiling, and molecular typing of pathogens) and analytical (electrophoresis, gel electrophoresis, surface-enhanced Raman scattering, and mass spectrometry) tools have been developed in recent years for the identification of bacteria and diagnosis of bacterial infections from clinical samples. Among mass spectrometric techniques, electrospray ionization (ESI) and rapid evaporative ionization (REI) mass spectrometric (MS) techniques have attracted much attention in the identification of microorganisms (bacteria, fungi, and viruses), and in the diagnosis of various bacterial infections. This review highlights the developed ESI-MS-based methods, including polymerase chain reaction (PCR) combined with ESI-MS and capillary electrophoresis (CE) and liquid chromatography (LC)-ESI-MS, for the identification of microorganisms (pathogenic bacteria, fungi, and viruses) in various samples. Recent applications of ESI- and REI-MS in identifying pathogenic bacteria are depicted in tables, and some significant findings are summarized.

Cysteine capped copper/molybdenum bimetallic nanoclusters for fluorometric determination of methotrexate via the inner filter effect.

A method is reported for the synthesis of highly luminescent copper/molybdenum bimetallic nanoclusters (Cu/Mo NCs) using cysteine as both a capping and reducing agent. The nanoclusters display bluish-green luminescence (excitation/emission peaks at 370/490 nm) and a relative quantum yield of 26%. The capped Cu/Mo NCs were used as a fluorescent probe for determination of the antineoplastic drug methotrexate (MTX) via an inner filter effect. Fluorescence intensity decreases linearly in the 50 nM to 100 µM MTX concentration range. The limit of detection is 13.7 nM. This approach has been successfully applied to the determination of MTX in spiked human urine with a typical recovery of 99%. Graphical abstract Schematic of a fluorometric method for the determination of methotrexate (MTX) which exerts a strong inner filter effect on the fluorescence of cysteine-capped copper/molybdenum nanoclusters (CuMo NCs) at the wavelength of excitation (370 nm).

Comparative Photothermal Performance among Various Sub-Stoichiometric 2D Oxygen-Deficient Molybdenum Oxide Nanoflakes and In†Vivo Toxicity.

The present study deals with photothermal therapy of solid tumors using different forms of oxygen-deficient sub-stoichiometric two-dimensional (2D) molybdenum oxide nanoflakes (α-MoO3-x ). Upon exfoliation of molybdenum oxide power using fine gridding followed by ultrasonication, bluish green molybdenum oxide (BG α-MoO3 ) was obtained. Oxygen vacancies in BG were generated upon irradiation with an intense xenon lamp. Irradiating the BG for 3 and 5 h, deep blue (B) and olive green (G) oxygen-deficient nanoflakes were obtained respectively. All exhibited high NIR absorption, making these nanomaterials suitable for photothermal therapy. All three forms were functionalized with polypyrrole (PPy@BG, PPy@B, PPy@G) to boost the photothermal stability and transduction efficiency. After functionalization and irradiation with 808 nm laser, the enhancement of temperature for BG, B, G was 50, 65, 52 °C respectively and the corresponding photothermal transduction efficiencies (PTE) were 29.32, 44.42 and 42.00 %. Each of the nanoflakes were found to be highly biocompatible and photostable both in vitro and in vivo. There was substantial decrease in the size of tumors after seven days of treatment on tumor-bearing experimental mice models.

Surface tuning laser desorption/ionization mass spectrometry (STLDI-MS) for the analysis of small molecules using quantum dots.

In most applications of quantum dots (QDs) for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS), one side of QDs is supported by a solid substrate (stainless - steel plate), whereas the other side is in contact with the target analytes. Therefore, the surface capping agent of QDs is a key parameter for laser desorption/ionization mass spectrometry (LDI-MS). Cadmium telluride quantum dots (CdTe QDs) modified with different capping agents are synthesized, characterized, and applied for surface tuning laser desorption/ionization mass spectrometry (STLDI-MS). Data shows that CdTe quantum dot modified cysteine (cys@CdTe QDs) has an absorption that matches with the wavelength of the N2 laser (337 nm). The synergistic effect of large surface area and absorption of the laser irradiation of cys@CdTe QDs enhances the LDI-MS process for small - molecule analysis, including α-, ß-, and γ-cyclodextrin, gramicidin D, perylene, pyrene, and triphenylphosphine. Cys@CdTe QDs are also applied using Al foils as substrates. Aluminum foil combined with cys@CdTe QDs enhances the ionization efficiency and is cheap compared to traditional matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with a stainless - steel plate.

Glucose oxidase assisted visual detection of glucose using oxygen deficient α-MoO3-x nanoflakes.

An optical method is described for the quantitation of glucose by using oxygen-deficient α-MoO3-x nanoflakes. It is based on the use of glucose oxidase (GOx) which produces hydrogen peroxide on oxidation of glucose. Hydrogen peroxide then oxidizes the α-MoO3-x nanoflakes, and this results in a visible color change from blue to colorless. The color change can be measured photometrically at 740 nm. The method has a 68 nM detection limit. Graphical Abstract Mechanism of glucose detection using blue colored oxygen deficient 2D α-MoO3-x nanoflakes. Hydrogen peroxide (H2O2) is formed as a by-product in the conversion of glucose to glucono-1,5-lactone by glucose oxidase (GOx). In the presence of H2O2, the oxygen vacancies in α-MoO3-x nanoflakes are filled up, and this leads to the loss of blue color of the nanoflakes because they are converted back to colorless bulk α-MoO3.

CoFe2 O4 -ZnO nanoparticles for rapid microwave-assisted tryptic digestion of phosphoprotein and phosphopeptide analysis by matrix-assisted laser desorption/ionization mass spectrometry.

RATIONALE: Phosphorylation is a post-translational modification of proteins that plays very important role in a large number of biological processes. However, despite recent advancements in phosphoproteome research, large-scale detection and characterization of phosphopeptides by mass spectrometry (MS) is still a challenging task due to the low abundance of phosphopeptides and sub-stoichiometric nature of phosphorylation sites. On-particle microwave-assisted trypsin digestion of phosphoproteins and enrichment of phosphopeptides is an effective method for identification/characterization of phosphopeptides. Magnetic nanoparticles typically can absorb microwave radiation and generate heat in order to resolve complex phosphproteins and to enhance the digestion rate and capture the phosphopeptides on their modified surfaces. METHODS: In this study, we used a cheap and efficient method for rapid microwave-assisted tryptic digestion of phosphoproteins and simultaneous enrichment of phosphopeptides using CoFe2 O4 -ZnO magnetic nanoparticles. Using this technique, the digestion time of phosphoproteins can be reduced and the phosphopeptides can be quickly analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). For the first time, we have applied CoFe2 O4 -ZnO magnetic nanoparticles for enrichment of phosphopeptides from standard phosphoproteins (ß-casein and ovalbumin), complex samples (human serum and egg white) and a protein mixture of ß-casein and BSA (1:100). RESULTS: Our results demonstrate that the capture efficiency of CoFe2 O4 -ZnO nanoparticles for ß-casein and ovalbumin in MALDI-TOFMS is very high (detection limits 0.2 fmol and 20 fmol, respectively). The CoFe2 O4 -ZnO nanoparticles have high affinity for phosphopeptide enrichment for ß-casein in complex mixtures with BSA at 1:10 and 1:100 molar ratios in the microwave within 30 s. CONCLUSIONS: Compared with other reported magnetic nanoparticles, the CoFe2 O4 -ZnO nanoparticles are easy to prepare and handle, and can save time in the phosphopeptide enrichment procedure, making these nanoparticle a good choice for highly sensitive phosphopeptide enrichment. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of surface capping of quantum dots (CdTe) on proteomics.

RATIONALE: Investigation of nanoparticles for laser desorption/ionization mass spectrometry (LDI-MS) is routinely reported. However, the effect of surface capping of nanomaterials for LDI-MS is not well studied. METHODS: Different capping agents of quantum dots (CdTe) affect the spectra quality and sensitivity of protein analysis and protein digestion using trypsin enzyme assisted by microwave. Surface modification of CdTe quantum dots with different capping agents, namely 3-mercaptopropionic acid (3-MPA), 4-aminothiophenol (4-ATP), 4-mercaptobenzoic acid (4-MBA), 11-mercaptoundecanoic acid (11-MUA), cysteine (Cys) and thioglycolic acid (TG), were investigated for quantum dots (QDs)-assisted trypsin protease followed by analysis using mass spectrometry. RESULTS: CdTe QDs were used as a surface to assist trypsin protease and laser desorption/ionization mass spectrometry (surface-assisted laser desorption/ionization mass spectrometry, SALDI-MS). The MS profiles for the investigated analytes (bovine serum albumin (BSA), lysozyme, cytochrome c, α-casein, transferrin and myoglobin) revealed almost the absence of degradation that implies the softness of the present technique. QDs-assisted LDI-MS offered high sensitivity and high resolution. QDs showed significant enhancement of microwave-assisted trypsin digestion of the investigated proteins and these improvements boosted the identifications of fragments with a database. CONCLUSIONS: A capping agent of quantum dots affects the analysis of proteins and peptides using LDI-MS. CdTe QDs offer sensitive, high-resolution and simple analysis of proteins. QDs improved the protein digestion using the microwave-assisted trypsin digestion. Copyright © 2016 John Wiley & Sons, Ltd.

Gold nanoparticles assisted laser desorption/ionization mass spectrometry and applications: from simple molecules to intact cells.

Gold nanoparticles (AuNPs) assisted laser desorption/ionization mass spectrometry (GALDI-MS) provided new horizons and offered many functions for various applications. This review summarized AuNPs applications for analytical, biotechnology and proteomics. AuNPs efficiently absorbed the laser radiation and transferred the energy to the analyte for the desorption/ionization process. The unique features of AuNPs such as large surface area and high absorption coefficient lead not only to high resolution, low interference and low limit of detection, but also offered selective detection for certain species. AuNPs provided an excellent surface for the analysis of several species such as small molecules, biomarkers, proteins and cells (pathogenic bacteria or cancer cells). AuNPs played many roles such as surface for LDI-MS, probe and stationary phase for separation or preconcentration. AuNPs modified various surface chemistry was applied for a wide range of different wavelength. AuNPs severed as a source of Au(+) ions that were suitable for analyte cationisation. Characterization of Au nanoclusters (AuNCs) by mass spectrometry, pros and cons were also highlighted. Graphical Abstract Schematic representation of the analysis by Gold Nanoparticles Assisted Laser Desorption/Ionization Mass Spectrometry (GALDI-MS).

Large protein analysis of Staphylococcus aureus and Escherichia coli by MALDI TOF mass spectrometry using amoxicillin functionalized magnetic nanoparticles.

Bacteria or their protein and peptide entity enrichment using biomolecules-functionalized magnetic nanoparticles, and analysis by matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) is a promising technique to analyze microorganisms. High and low molecular weight proteins like penicillin-binding proteins are responsible for final step synthesis of peptidoglycan biosynthesis; those are the target of lactam antibiotics. In this paper, we synthesized magnetic nanoparticles (mag-NPs) and further modified them with 3-aminopropyltriethoxysilane, and then the ß-lactam antibiotic amoxicillin was covalently linked to their surface. ß-Lactam group attributes as penicillin binding proteins (PBPs) in bacteria. Staphylococcus aureus and Escherichia coli were used as model bacteria for enrichment based on the ß-lactam affinity of magnetic nanoparticles, and then the bacteria were easily separated by an external magnet. Several high molecular weight penicillin binding proteins (PBPs) were detected by MALDI MS containing 10(4) and 10(3) colony-forming unit (cfu) per milileter (mL) of S. aureus and E. coli, respectively. In the case of E. coli, higher molecular weight PBPs were observed at 20 to 55 kDa in MALDI mass spectra. However, S. aureus bacteria resulted with femAB operon-based proteins, with molecular weight of 49570.4 Da, by MALDI MS after using amoxicillin functionalized-mag-NPs. The current approach provides an effective bacteria detection and preconcentration method that has high potential in the near future for fast and sensitive diagnosis of pathogenic bacteria infection. Graphical Abstract Schematic for large proteins analysis by MALDI TOF MS (a) mag-NPs and bacterial interaction (b) Penicillin binding proteins trapping by Amox-mag-NPs.

Synthesis of a highly dispersive sinapinic acid@graphene oxide (SA@GO) and its applications as a novel surface assisted laser desorption/ionization mass spectrometry for proteomics and pathogenic bacteria biosensing.

Graphene oxide (GO)-modified sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) (SA@GO) was synthesized and characterized; it was then investigated as a new surface assisted laser desorption/ionization mass spectrometry (SALDI-MS) for proteomics and pathogenic bacteria biosensing. SA@GO could effectively decrease the time necessary for sweet spotting searching, reducing the amount of organic matrix and solvent and enhance the sensitivity. SA@GO shows high performance as a matrix alone without the need to add trifluoroacetic acid (TFA). However, the analysis of the intact bacteria cells shows improvement in the signal intensity (2-5 fold) and offers a low limit of detection. All these analyses could be performed with low concentrations (1-10 fmol) and tiny volumes (0.5-1 µL). This study demonstrated that the exploration of new hybrid materials is pivotal to achieve high performance and high ionization. Because of the plane of GO, it assists protein-protein interactions that make it undergo softer ionization.

Genotyping of intron 22 inversion of factor VIII gene for diagnosis of hemophilia A by inverse-shifting polymerase chain reaction and capillary electrophoresis.

This is the first capillary electrophoresis (CE) analysis for diagnosis of hemophilia A (HA). The intron 22 inversion of factor VIII gene (F8) causes 40-50 % of severe bleeding disorder of HA in all human populations. Consequently, identification of the disease-causing mutations is becoming increasingly important for accurate genetic counseling and prenatal diagnosis. In this study, the key steps of inverse-shifting polymerase chain reaction (IS-PCR) and of short-end injection capillary electrophoresis were used for more specific and rapid genotyping of intron 22 inversion of F8. In IS-PCR, three specific primers were used to amplify 512-bp amplicon for wild type and 584-bp amplicon for patients with intron 22 inversion. The capillary gel electrophoresis (CGE) system was performed using 1× Tris-borate-EDTA (TBE) buffer containing 0.3 % (w/v) polyethylene oxide (PEO). The PCR amplicons were electrokinetically injected at 10 kV for 10 s at a temperature of 25 °C. The optimal short-end injection CGE was applied to detect the F8 gene of HA patients and carriers within 5 min. Intron 22 inversion was indeed found on some HA patients (13/35, 37.1 %). All genotyping results showed good agreement with DNA sequencing method and long-distance polymerase chain reaction (LD-PCR). The IS-PCR combined with short-end injection CGE method was feasible and efficient for intron 22 inversion screening of F8 in the HA populations.

Surface modified quantum dots as fluorescent probes for biomolecule recognition.

The development of novel nanomaterial-based analytical methods for biological analysis in proteomics and clinical diagnosis has been making significant progress. In the long-lasting efforts to improve the detection sensitivity of analytical instruments, functional nanomaterials have been significantly applied as effective probes by integrating various analytical tools for bioanalysis. Among these nanomaterials, quantum dots (QDs) have been recently proved as highly potential materials as fluorescent sensors for biomolecules assays due to their high quantum yield, narrow and tunable emission spectrum and excellent photostability. In this review, we introduce the use of surface modified QDs as fluorescence probes for detecting proteins, peptides and other biomolecules based on fluorescence quenching and fluorescence resonance energy transfer (FRET).

Two-dimensional oxygen-deficient ZnO1-x nanosheet as a highly selective and sensitive fluorescence probe for ferritin detection: the electron transfer biosensor (ETBS).

Iron proteins are of great scientific interest due to their importance as an excellent biomarker for human diseases. Ferritin (Fe3+), being an iron-rich blood protein, is related to various diseases like anemia and cancer. For the first time, we have developed a highly sensitive and selective ferritin biosensor based on fluorescent oxygen-deficient zinc oxide nanosheets through hydrothermal and probe-ultrasonication combined methods. The fluorescence study showed an intense bluish-green fluorescence at λex = 370 nm, after optimization at different excitation wavelengths. In addition, the fluorescence of ZnO1-x nanosheets can be efficiently quenched due to electron transfer reactions in order to achieve quantification analysis. The limit of detection (LOD) was calculated to be 0.015 nM (7.2 ng mL-1) with high linearity (R2 = 0.9930). In addition, the real-world application of the proposed biosensor has been performed on human blood serum samples in the presence of various interfering analytes showing high selectivity and sensitivity with a regression value R2 = 0.9980 indicating the current approach is an excellent biosensor platform.

Pentacenequinone-Modulated 2D GdSn-PQ Nanosheets as a Fluorescent Probe for the Detection of Enrofloxacin in Biological and Environmental Samples.

The fate and effects of fluoroquinolone antibacterial (FQ) on the environment are important since there appears to be a surge in FQ resistance like enrofloxacin (ENR) in both environmental and clinical organisms. Numerous reports indicate that the sensing capabilities of these antibiotics need to be improved. Here, we have investigated the interaction of ENR with our synthesized pentacenequinone-modulated gadolinium-tin (GdSn-PQ) nanosheets and the formation of intermolecular interactions that caused the occurrence of aggregation-induced emission enhancement. The concept for designing hybrid metallic nanosheets comes from the unique features inherited from the parent organic precursor. Due to the distinct interaction between ENR and GdSn-PQ, the interstate conversion (ISC) between GdSn-PQ and ENR induces a significant wavelength shift in photoluminescence (PL), improving reliability, selectivity, and visibility compared to quenching- or AIEE-based methods without peak shifts, allowing for highly sensitive and visually detectable analyses. The fluorescence signal of GdSn-PQ exhibited a linear relationship (R2 = 0.9911), with the added ENR concentrations ranging from 5 to 90 nM, with a detection limit of 0.10 nM. We have demonstrated its potential and wide use in the detection of ENR in biological samples (human urine and blood serum) and environmental samples (tap water and seawater) with a recovery rate of 98- 108%. The current approach has demonstrated that the 2D GdSn-PQ nanosheet is a novel and powerful platform for future biological and environmental studies.

Crosstalk between H2O2 and Ca2+ signaling is involved in root endophyte-enhanced tanshinone biosynthesis of Salvia miltiorrhiza.

Tanshinones are bioactive ingredients derived from the herbal plant Salvia miltiorrhiza and are used for treating diseases of the heart and brain, thus ensuring quality of S. miltiorrhiza is paramount. Applying the endophytic fungus Trichoderma atroviride D16 can significantly increase the content of tanshinones in S. miltiorrhiza, but the potential mechanism remains unknown. In the present study, the colonization of D16 effectively enhanced the levels of Ca2+ and H2O2 in the roots of S. miltiorrhiza, which is positively correlated with increased tanshinones accumulation. Further experiments found that the treatment of plantlets with Ca2+ channel blocker (LaCl3) or H2O2 scavenger (DMTU) blocked D16-promoted tanshinones production. LaCl3 suppressed not only the D16-induced tanshinones accumulation but also the induced Ca2+ and H2O2 generation; nevertheless, DMTU did not significantly inhibit the induced Ca2+ biosynthesis, implying that Ca2+ acted upstream in H2O2 production. These results were confirmed by observations that S. miltiorrhiza treated with D16, CaCl2, and D16+LaCl3 exhibit H2O2 accumulation and influx in the roots. Moreover, H2O2 as a downstream signal of Ca2+ is involved in D16 enhanced tanshinones synthesis by inducing the expression of genes related to the biosynthesis of tanshinones, such as DXR, HMGR, GGPPS, CPS, KSL and CYP76AH1 genes. Transcriptomic analysis further supported that D16 activated the transcriptional responses related to Ca2+ and H2O2 production and tanshinones synthesis in S. miltiorrhiza seedlings. This is the first report that Ca2+ and H2O2 play important roles in regulating fungal-plant interactions thus improving the quality in the D16-S. miltiorrhiza system.