Masking effects on iso-valeric acid recognition by sub-threshold odor mixture.

Masking unpleasant odors with pleasant-smelling odorants has a long history and is utilized in various industries, including perfumery and consumer products. However, the effectiveness of odor masking is idiosyncratic and temporary. In this study, we employed Sniff olfactometry (SO) to investigate the psychophysics of masking using brief 70 ms stimulations with mixtures of the mal-odorant iso-valeric acid (IVA) and different masking agents. IVA is a component of human sweat that can overpower its smell and is often associated with unpleasant descriptors such as "gym locker," "smelly feet," "dirty clothes," and so on. Traditionally, high concentrations of pleasant-smelling odorants are used to mitigate the unpleasantness of IVA in situations involving clothing or environments contaminated with IVA. To examine the masking effects of sub-threshold levels of various masking agents (neohivernal, geraniol, florhydral, decanal, iso-longifolanone, methyl iso-eugenol, and s-limonene) on IVA, we conducted experiments using SO to measure the probability of recognizing IVA after 70 ms stimulations with headspaces containing mixtures of super-threshold concentrations of IVA and sub-threshold concentrations of IVA suppressors. The study involved nine subjects, and on average, a single masking agent was found to decrease IVA recognition probability by 14-72%. Moreover, a sub-threshold odor mixture consisting of 6 masking agents demonstrated a substantial decrease in IVA recognition, with a reduction of 96%.

Different pregnancy outcomes in patients with systemic lupus erythematosus treated with belimumab.

OBJECTIVES: Systemic lupus erythematosus (SLE) predominantly occurs in women of child-bearing age. Selecting drugs for pregnant SLE patients has always been a difficult choice. Although there have been several reports of safety of belimumab in SLE patients during pregnancy, the data are far from sufficient. METHODS: We report on 4 cases of belimumab exposure in pregnant SLE patients. We also summarized 6 case reports and case series which were previously published. Further, we compared the different outcomes among SLE patients and their babies who continued with belimumab during pregnancy with those who discontinued belimumab in early pregnancy. RESULTS: Two cases discontinued belimumab in the early pregnancy, while the other two received belimumab until the late pregnancy. All the four women tolerated belimumab. Newborns have all developed normally and continue without complications during 1 year of follow-up. CONCLUSION: In this small case series, we found that belimumab was well tolerated in pregnant SLE patients. There were no safety signals for the mothers or their babies.

Comparison between outcomes of IgA nephropathy with nephrotic-range proteinuria and nephrotic syndrome: do podocytes play a role?

BACKGROUND: Nephrotic syndrome (NS) and nephrotic-range proteinuria (NRP) are uncommon in IgA nephropathy (IgAN), and their clinicopathology and prognosis have not been discussed. Podocytes may play an important role in both clinical phenotypes. METHODS: We investigated 119 biopsy-proven IgAN patients with proteinuria over 2 g/d. The patients were divided into three groups according to proteinuria level: the overt proteinuria (OP) group, NS group, and NRP group. In addition, according to the severity of foot process effacement (FPE), the patients were divided into three groups: the segmental FPE (SFPE) group, moderate FPE (MFPE) group, and diffuse FPE (DFPE) group. The outcome was survival from a combined event defined by a doubling of the baseline serum creatinine and a 50% reduction in eGFR or ESRD. RESULTS: Compared with the NRP group, patients in the NS group had more severe microscopic hematuria, presented with more severe endocapillary hypercellularity and had a higher percentage of DFPE. The Kaplan-Meier curve showed that MFPE patients had a better outcome in the NRP group <50% of tubular atrophy/interstitial fibrosis. In the multivariate model, the NRP group (HR = 17.098, 95% CI = 3.835-76.224) was associated with an increased risk of the combined event, while MFPE (HR = 0.260, 95% CI = 0.078-0.864; p = 0.028) was associated with a reduced risk of the combined event. After the addition of renin-angiotensin system inhibitors (RASi), the incidence of the combined event in the MFPE group (HR = 0.179, 95% CI = 0.047-0.689; p = 0.012) was further reduced. CONCLUSIONS: NS presented more active lesions and more severe FPE in IgAN. NRP was an independent risk factor for progression to the renal endpoint, while MFPE indicated a better prognosis in NRP without obvious chronic renal lesions, which may benefit from RASi.

p53 induces miR-199a-3p to suppress mechanistic target of rapamycin activation in cisplatin-induced acute kidney injury.

How p53 participates in acute kidney injury (AKI) progress and what are the underlying mechanisms remain illusive. For this issue, it is important to probe into the role of p53 in cisplatin-induced AKI. We find that p53 was upregulated in cisplatin-induced AKI, yet, pifithrin-α inhibites the p53 expression to attenuated renal injury and cell apoptosis both in vivo cisplatin-induced AKI mice and in vitro HK-2 human renal tubular epithelial cells. To knock down p53 by siRNA significantly decreased the miRNA, miR-199a-3p, expression in HK-2 cells. Blockade of miR-199a-3p significantly reduced cisplatin-induced cell apoptosis and inhibited caspase-3 activity. Mechanistically, we identified that miR-199a-3p directly bound to mechanistic target of rapamycin (mTOR) 3'-untranslated region and overexpressed miR-199a-3p reduce the expression and phosphorylation of mTOR. Furthermore, we demonstrated that p53 inhibited mTOR activation through activating miR-199a-3p. In conclusion, our findings reveal that p53, upregulating the expression of miR-199a-3p affects the progress of cisplatin-induced AKI, which might provide a promising therapeutic target of AKI.

Aptamer based label free thrombin assay based on the use of silver nanoparticles incorporated into self-polymerized dopamine.

The authors describe an electrochemical aptasensor for thrombin that is based on the use of a glassy carbon electrode (GCE) modified with polydopamine that is loaded with silver nanoparticles (PDA/AgNPs). The use of AgNPs improves the conductivity of the film and increases the surface area of the GCE. PDA was deposited on the GCE via self-polymerization, and the thrombin binding aptamer was grafted onto the PDA-modified GCE by a single step reaction. Residual electrode surface was blocked with 6-mercapto-1-hexanol. On exposure to thrombin, the electrochemical impedance of the modified electrode increases gradually. Response is linear in the 0.1 pM to 5.0 nM thrombin concentration range, and the limit of detection is as low as 36 fM. The method is selective and capable of detecting thrombin in diluted human serum. In our perception, such a GCE modified with AgNP in a PDA matrix may be applied to many other analytes for which appropriate aptamers are available. Graphical abstract Schematic of an electrochemical aptasensor for sensitive and selective thrombin detection based on the use of a self-polymerized polydopamine film loaded with silver nanoparticles.

Treatment of Ankylosing Spondylitis With a Bushen-Qiangdu-Zhilv Decoction: A Case Report With a 3-year Follow-up.

Context • Ankylosing spondylitis (AS) is a refractory rheumatic disease, characterized by sacroiliitis and structural damage, and over decades, it can lead to joint fusion, frequently followed by significant spinal deformity and disability. However, to date, no method has been found to be effective in relieving or blocking structural damage to joints. Objective • The study intended to show that a decoction of Bushen-Qiangdu-Zhilv (BQZ), a therapy used in traditional Chinese medicine (TCM), can provide an alternative treatment for AS patients. Design • The research team performed a case study. Setting • The study was conducted at Guangdong Provincial Hospital of TCM in Guangzhou, China. Participant • The case study involved a 33-y-old male patient with active AS who visited the research team's clinic. Intervention • The patient took the BQZ orally 2 ×/d at 30 min after breakfast and 30 min after dinner. The patient returned to the clinic for consultation monthly. The patient took 2 servings/d for 10 mo and then received continuous BQZ treatment of the maintenance dosage for a period of approximately 3 y until December 2013. The maintenance dosage of BQZ was 3 or 4 decoctions per wk. Outcome Measures • The study used a number of measurements to evaluate the outcomes of treatment: (1) disease activity-the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI); (2) functional condition-the Bath Ankylosing Spondylitis Functional Index (BASFI); (3) inflammation-ratings of morning stiffness and night pain, serum C-reactive protein (CRP) concentration measured by means of particle-enhanced immunonephelometry, and erythrocyte sedimentation rate (ESR) value as detected using the Westergren method; (4) spinal mobility-the Bath Ankylosing Spondylitis Metrology Index (BASMI); and (5) global assessments by patient and physician. Results • The participant showed improvements in inflammatory symptoms and recovery from structural damage after receiving the TCM therapy for 3 y. Conclusions • The study has shown that the long-term use of BQZ not only can lead to an improvement in inflammatory symptoms and quality of life but also can help to restore function after structural damage in AS patients.

Anti-inflammatory activity of extracts of Bushen-Qiangdu-Zhilv decoction, a Chinese medicinal formula, in M1-polarized RAW264.7.

BACKGROUND: Bushen-Qiangdu-Zhilv Decoction (BQZ) is one of famous traditional Chinese medical formula for treating ankylosing spondylitis (AS). However, the mechanisms underlying effects of BQZ remains unknown. Pro-inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1, play an important role in AS. We therefore evaluated if BQZ could affect the expression of these cytokines. METHODS: Crude extracts were prepared and fractioned with petroleum ether (PE), ethyl acetate (EA), n-butanol (BU) and finally water (ACE). The stability of the extracts was confirmed by high-pressure liquid chromatography (HPLC) analysis. M1-polarized RAW264.7 was induced and subsequently treated with BQZ extracts. Quantitative real-time PCR experiments were performed to measure mRNA expression of TNF-α and IL-1. RESULTS: It was found that TNF-α could be significantly suppressed by ACE extracts, whereas IL-1 was dramatically inhibited by BU extracts, which was further confirmed by dose-dependent experiments. Importantly, MTS assays showed that both ACE and BU extracts had a low cytotoxicity. CONCLUSION: Altogether, our study indicates that BQZ decoction exerts anti-AS effects via its anti-inflammatory activity and may have a low side-effect. Further analysis of the extracts of BQZ decoction could lead to a discovery of some novel drugs adding to therapeutic strategy for AS patients.

Normal-weight central obesity: implications for diabetes mellitus.

Background: Current guidelines for obesity prevention and control focus on body mass index (BMI) and rarely address central obesity. Few studies have been conducted on the association between normal-weight central obesity and the risk of diabetes mellitus (DM). Methods: 26,825 participants from the National Health and Nutrition Examination Survey (NHANES) were included in our study. A weighted multivariate logistic regression model was used to analyze the relationship between different obesity patterns and the risk of DM. Results: Our results suggest that normal-weight central obesity is associated with an increased risk of DM (OR: 2.37, 95% CI: 1.75-3.23) compared with normal-weight participants without central obesity. When stratified by sex, men with normal-weight central obesity, obesity and central obesity were found to have a similar risk of DM (OR: 3.83, 95% CI: 2.10-5.97; OR: 4.20, 95% CI: 3.48-5.08, respectively) and a higher risk than all other types of obesity, including men who were overweight with no central obesity (OR: 1.21, 95% CI: 0.96-1.51) and obese with no central obesity (OR: 0.53, 95% CI: 0.30-0.91). Conclusion: Our results highlight the need for more attention in people with central obesity, even if they have a normal BMI.

Fluorescence detection of thrombin using autocatalytic strand displacement cycle reaction and a dual-aptamer DNA sandwich assay.

A sensitive and specific sandwich assay for the detection of thrombin is described. Two affiliative aptamers were used to increase the assay specificity through sandwich recognition. Recognition DNA loaded on gold nanoparticles (AuNPs) partially hybridized with the initiator DNA, which was displaced by surviving DNA. After the initiator DNA was released into the solution, one hairpin structure was opened, which in turn opened another hairpin structure. The initiator DNA was displaced and released into the solution again by another hairpin structure because of the hybridized reaction. Then the released initiator DNA initiated another autocatalytic strand displacement reaction. A sophisticated network of three such duplex formation cycles was designed to amplify the fluorescence signal. Other proteins, such as bovine serum albumin and lysozyme, did not interfere with the detection of thrombin. This approach enables rapid and specific thrombin detection with reduced costs and minimized material consumption compared with traditional assay processes. The detection limit of thrombin was as low as 4.3 × 10⁻¹³ M based on the AuNP amplification and the autocatalytic strand displacement cycle reaction. This method could be used in biological samples with excellent selectivity.

A label-free immunosensor by controlled fabrication of monoclonal antibodies and gold nanoparticles inside the mesopores.

A label-free immunosensor for the detection of α-fetoprotein (AFP) is proposed based on controlled fabrication of monoclonal antibodies of AFP (anti-AFP) and gold nanoparticles (GNPs) inside the pores of mesoporous silica (MPS). The silanol groups on the internal pore walls were grafted by aminopropyltriethoxyl silane, whereas the silanol groups on the external surface of MPS were blocked by trimethylchlorosilane (TMCS). Thus, anti-AFP and GNPs could be confined inside the mesopores of TMCS-MPS by the covalent linking with the amino groups. The prepared anti-AFP/GNPs/TMCS-MPS particles were used to modify glassy carbon electrode (GCE) to construct a label-free immunosensor. After incubating the sample AFP with the anti-AFP/GNPs/TMCS-MPS/GCE, the immunoconjugates were formed on the surface of GCE and the spatial block increased. Thus, the peak current decreased with increasing concentrations of AFP. GNPs inside the mesopores could promote the electron transportation through the pore channel. Under the optimal experimental conditions, the fabricated immunosensor could detect AFP in a linear range from 1.0 to 90 ng ml(-1) with a detection limit of 0.2 ng ml(-1) (3σ). It provided a novel alternative method for the label-free determination of other antigens.

Metagenome-wide association study of the alterations in the intestinal microbiome composition of ankylosing spondylitis patients and the effect of traditional and herbal treatment.

Introduction. Ankylosing spondylitis (AS) is a systemic progressive disease with an unknown etiology that may be related to the gut microbiome. Therefore, a more thorough understanding of its pathogenesis is necessary for directing future therapy.Aim. We aimed to determine the differences in intestinal microbial composition between healthy individuals and patients with AS who received and who did not receive treatment interventions. In parallel, the pathology of AS in each patient was analysed to better understand the link between AS treatment and the intestinal microbiota of the patients.Methodology. Sixty-six faecal DNA samples, including 37 from healthy controls (HCs), 11 from patients with untreated AS (NM), 7 from patients treated with nonsteroidal anti-inflammatory drugs (e.g. celecoxib; WM) and 11 from patients treated with Chinese herbal medicine (CHM), such as the Bushen-Qiangdu-Zhilv decoction, were collected and used in the drug effect analysis. All samples were sequenced using Illumina HiSeq 4000 and the microbial composition was determined.Results. Four species were enriched in the patients with AS: Flavonifractor plautii, Oscillibacter, Parabacteroides distasonis and Bacteroides nordii (HC vs. NM, P<0.05); only F. plautii was found to be significantly changed in the NM-HC comparison. No additional species were found in the HC vs. CHM analysis, which indicated a beneficial effect of CHM in removing the other three strains. F. plautii was found to be significantly increased in the comparison between the HC and WM groups, along with four other species (Clostridium bolteae, Clostridiales bacterium 1_7_47FAA, C. asparagiforme and C. hathewayi). The patients with AS harboured more bacterial species associated with carbohydrate metabolism and glycan biosynthesis in their faeces. They also had bacterial profiles less able to biodegrade xenobiotics or synthesize and transport vitamins.Conclusion. The gut microbiota of the patients with AS varied from that of the HCs, and the treatment had an impact on this divergence. Our data provide insight that could guide improvements in AS treatment.

Sensitive amperometric immunosensor for alpha-fetoprotein based on carbon nanotube/gold nanoparticle doped chitosan film.

A novel strategy for the fabrication of sensitive immunosensor to detect alpha-fetoprotein (AFP) in human serum has been proposed. The immunosensor was prepared by immobilizing AFP antigen onto the glassy carbon electrode (GC) modified by gold nanoparticles and carbon nanotubes doped chitosan (GNP/CNT/Ch) film. GNP/CNT hybrids were produced by one-step synthesis based on the direct redox reaction. The electrochemical properties of GNP/CNT/Ch films were characterized by impedance spectroscopy and cyclic voltammetry. It was indicated that GNP/CNT nanohybrid acted as an electron promoter and accelerated the electron transfer. Sample AFP, immobilized AFP, and alkaline phosphatase (ALP)-labeled antibody were incubated together for the determination based on a competitive immunoassay format. After the immunoassay reaction, the bound ALP label on the modified GC led to an amperometric response of 1-naphthyl phosphate (1-NP), which was changed with the different antigen concentrations in solution. Under the optimized experimental conditions, the resulting immunosensor could detect AFP in a linear range from 1 to 55 ng ml(-1) with a detection limit of 0.6 ng ml(-1). The proposed immunosensor, by using GNP/CNT/Ch as the immobilization matrix of AFP, offers an excellent amperometric response of ALP-anti-AFP to 1-NP. The immunosensor provided a new alternative to the application of other antigens or other bioactive molecules.

A channel-resolved approach coupled with magnet-captured technique for multianalyte chemiluminescent immunoassay.

A concept of channel-resolved multianalyte immunoassay (MAIA) and a semi-automated flow-through chemiluminescent (CL) MAIA system coupled with magnet-captured technique were proposed for rapid quantitation of different analytes in a single run. Using alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA) and carcinoma antigen 125 (CA 125) as model analytes. They were firstly incubated in the mixtures of capture antibodies-immobilized paramagnetic microspheres (PMs) and corresponding alkaline phosphatase-labeled antibodies under stir and pumped into three parallel detection channels, the PMs were simultaneously captured by magnet, and the CL signals from the three channels were then sequentially collected with the aid of optical shutters to perform quantitative detection. AFP, CEA and CA 125 could be rapidly assayed in the ranges of 1.0-40microg/l, 0.20-30microg/l and 1.0-50kU/l with the detection limits of 0.60microg/l, 0.080microg/l and 0.70kU/l at 3sigma, respectively. After manual dispensing of specimen and reagents the whole assay process could be completed in 18min. The assay results of clinical serum samples with the proposed method were in acceptable agreement with the reference values. This system, based on the designed channel-resolved strategy and magnet-captured technique provides a semi-automated, reusable, simple, sensitive, rapid and low-cost approach for MAIA without using of expensive array detector.

3,3'-diaminobenzidine (DAB)-H2O2-HRP voltammetric enzyme-linked immunoassay for the detection of carcionembryonic antigen.

A new voltammetric enzyme-linked immunoassay system of 3,3'-diaminobenzidine (DAB)-H2O2-horseradish peroxidase (HRP) has been presented and used for the sensitive detection of carcinoembryonic antigen (CEA) in human serum. In this proposed procedure, DAB was firstly used as the electroactive substrate in the HRP catalyzed oxidation reaction in the present of H2O2. The generated product produced a sensitive second-order derivative linear sweep voltammetric peak at potential of -0.62 V (vs. SCE) in Britton-Robinson (BR) buffer solution. The free HRP could be measured in a linear range from 2.5 x 10(-6)-2.5 x 10(-2) unit/ml and a detection limit of about 1.5 x 10(-6) unit/ml. Under the optimal experiment conditions, CEA could be detected in the linear range from 0.50 to 80 ng/ml with a detection limit of 0.5 ng/ml. The proposed electrochemical enzyme-linked immunosorbent assay method is simple, inexpensive, reproducible and sensitive, which shows promising for detecting CEA in the clinical diagnosis.

Antifouling aptasensor for the detection of adenosine triphosphate in biological media based on mixed self-assembled aptamer and zwitterionic peptide.

Direct detection of targets in complex biological media with conventional biosensors is an enormous challenge due to the nonspecific adsorption and severe biofouling. In this work, a facile strategy for sensitive and low fouling detection of adenosine triphosphate (ATP) is developed through the construction of a mixed self-assembled biosensing interface, which was composed of zwitterionic peptide (antifouling material) and ATP aptamer (bio-recognition element). The peptide and aptamer (both containing thiol groups) were simultaneously self-assembled onto gold electrode surface electrodeposited with gold nanoparticles. The developed aptasensor possessed high selectivity and sensitivity for ATP, and it showed a wide linear response range towards ATP from 0.1pM to 5nM. Owing to the presence of peptide with excellent antifouling property in the biosensing interface, the aptasensor can detect ATP in complex biological media with remarkably reduced biofouling or nonspecific adsorption effect. Moreover, it can directly detect ATP in 1% human whole blood without suffering from any significant interference, indicating its great potential for practical assaying of ATP in biological samples.

Electrochemical immunosensor for carcinoembryonic antigen based on antigen immobilization in gold nanoparticles modified chitosan membrane.

A disposable electrochemical immunosensor for carcinoembryonic antigen (CEA) was proposed based on the antigen immobilized in a colloidal gold nanoparticles modified chitosan membrane on the surface of an indium-tin oxide (ITO) electrode. The different membranes were characterized by scanning electron microscope and electrochemical methods. Based on a competitive immunoassay format, the immobilized antigen of the immunosensor was incubated with a horseradish peroxidase (HRP) labeled antibody and sample CEA antigen, and the formed immunoconjugate in the immunosensor was detected by an o-phenylenediamine-H(2)O(2)-HRP electrochemical system. Under the optimal experimental conditions, the electrocatalytic current decreased linearly with the competitive mechanism. CEA could be determined in the linear range from 2.0 to 20 ng/ml with a detection limit of 1.0 ng/ml. The prepared CEA immunosensor is not only economic due to the low-cost ITO electrode obtained from industrial mass production, but is also capable with good stability and reproducibility for batch fabrication.

Mixed Self-Assembly of Polyethylene Glycol and Aptamer on Polydopamine Surface for Highly Sensitive and Low-Fouling Detection of Adenosine Triphosphate in Complex Media.

Detection of disease biomarkers within complex biological media is a substantial outstanding challenge because of severe biofouling and nonspecific adsorptions. Herein, a reliable strategy for sensitive and low-fouling detection of a biomarker, adenosine triphosphate (ATP) in biological samples was developed through the formation of a mixed self-assembled sensing interface, which was constructed by simultaneously self-assembling polyethylene glycol (PEG) and ATP aptamer onto the self-polymerized polydopamine-modified electrode surface. The developed aptasensor exhibited high selectivity and sensitivity toward the detection of ATP, and the linear range was 0.1-1000 pM, with a detection limit down to 0.1 pM. Moreover, owing to the presence of PEG within the sensing interface, the aptasensor was capable of sensing ATP in complex biological media such as human plasma with significantly reduced nonspecific adsorption effect. Assaying ATP in real biological samples including breast cancer cell lysates further proved the feasibility of this biosensor for practical application.

Aptamer induced multicoloured Au NCs-MoS2 "switch on" fluorescence resonance energy transfer biosensor for dual color simultaneous detection of multiple tumor markers by single wavelength excitation.

An aptamer induced "switch on" fluorescence resonance energy transfer (FRET) biosensor for the simultaneous detection of multiple tumor markers (e.g., AFP and CEA) combining molybdenum disulfide (MoS2) nanosheets with multicolored Au NCs by a single excitation was developed for the first time. Here, AFP aptamer functionalized green colored Au NCs (510 nm) and CEA aptamer functionalized red colored Au NCs (650 nm) are used as energy donors, while MoS2 is used as energy receptor. On the basis of recording the change of the recovered fluorescence intensity at 510 nm and 650 nm upon the addition of targets CEA and AFP, these two tumor markers can be simultaneously quantitatively detected, with detection limits of 0.16 and 0.21 ng mL-1 (3σ) for AFP and CEA, respectively. In addition, it is noteworthy that the developed biosensor can not only realize accurate quantitative determination of multiple tumor markers by fluorescent intensity, but also be applied in semi-quantitative determination through photo visualization. More importantly, confocal microscope experiments prove that serums from normal and hepatoma patients can also be visually and qualitatively discriminated by this FRET-based biosensor with a single excitation wavelength, indicating promising potential of this assay for clinical diagnosis.

Near infrared fluorescent dual ligand functionalized Au NCs based multidimensional sensor array for pattern recognition of multiple proteins and serum discrimination.

Here, a multidimensional sensor array capable of analyzing various proteins and discriminating between serums from different stages of breast cancer patients were developed based on six kinds of near infrared fluorescent dual ligand functionalized Au NCs (functionalized with different amino acids) as sensing receptors. These six kinds of different amino acids functionalized Au NCs were synthesized for the first time within 2h due to the direct donation of delocalized electrons of electron-rich atoms or groups of the ligands to the Au core. Based on this, ten proteins could be simultaneously and effectively discriminated by this "chemical nose/tongue" sensor array. Linear discrimination analysis (LDA) of the response patterns showed successful differentiation of the analytes at concentrations as low as 10nM with high identification accuracy. Isothermal titration calorimetry (ITC) experiment illustrates that Au NCs interacted with proteins mainly by hydrogen bonding and van der Waals forces. Furthermore, the greatest highlight of this sensor array is demonstrated by successfully discriminating between serums from different stages of breast cancer patients (early, middle and late) and healthy people, suggesting great potential for auxiliary diagnosis.

A novel dual-functional biosensor for fluorometric detection of inorganic pyrophosphate and pyrophosphatase activity based on globulin stabilized gold nanoclusters.

A novel ultrasensitive dual-functional biosensor for highly sensitive detection of inorganic pyrophosphate (PPi) and pyrophosphatase (PPase) activity was developed based on the fluorescent variation of globulin protected gold nanoclusters (Glo@Au NCs) with the assistance of Cu2+. Glo@Au NCs and PPi were used as the fluorescent indicator and substrate for PPase activity evaluation, respectively. In the presence of Cu2+, the fluorescence of the Glo@Au NCs will be quenched owing to the formation of Cu2+-Glo@Au NCs complex, while PPi can restore the fluorescence of the Cu2+-Glo@Au NCs complex because of its higher binding affinity with Cu2+. As PPase can catalyze the hydrolysis of PPi, it will lead to the release of Cu2+ and re-quench the fluorescence of the Glo@Au NCs. Based on this mechanism, quantitative evaluation of the PPi and PPase activity can be achieved ranging from 0.05 µM to 218.125 µM for PPi and from 0.1 to 8 mU for PPase, with detection limits of 0.02 µM and 0.04 mU, respectively, which is much lower than that of other PPi and PPase assay methods. More importantly, this ultrasensitive dual-functional biosensor can also be successfully applied to evaluate the PPase activity in human serum, showing great promise for practical diagnostic applications.