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When an acute myocardial infarction (AMI) occurs, myoglobin (Mb) is the biomarker whose concentration firstly increases, and the high sensitive detection of Mb is critical for early diagnosis of AMI. Herein, a sandwich-type electrochemical aptasensor for the sensitive detection of Mb was constructed by using Pt@Cu 1.33 OCo 0.83 O as the signal marker. On one hand, nano-flower-like Cu 1.33 OCo 0.83 O was synthesized by hydrothermal method and Pt nanoparticles (Pt NPs) were loaded on its surface. Pt@Cu 1.33 OCo 0.83 O could immobilize aptamer 2 (Apt2) successfully by the Pt-S bond. And because of the synergistic effect between Pt and bimetallic oxide, Pt@Cu 1.33 OCo 0.83 O had an excellent catalytic effect on the signal source of hydrogen peroxide (H 2 O 2 ) to amplify the current signal, which enhance the sensitivity of the aptasensor. On the other hand, the screen-printed gold electrode (SPGE) was used as the sensing base, which had good conductivity and ensured the immobilization of aptamer 1 (Apt1). The quantitative detection of Mb was achieved by specific recognition between Mb and Apt1, Apt2. As a result, the constructed electrochemical aptasensor had a good linear range (1-1500 ng/mL) with a low detection limit (LOD) of 0.128 ng/mL (S/N = 3), and a high sensitivity of 29.47 μA dec -1 . The aptasensor also realized the detection of Mb in human serum samples with good accuracy, and the results were consistent with the hospital's biochemical indicators, which demonstrated the potential application of the prepared sensor in the clinical detection of Mb., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

N-glycopeptide is considered as one of significant biomarkers which provide guidance for the diagnosis and drug design of diseases. However, the direct analysis of N-glycopeptides is nearly impracticable mainly owing to their extremely low abundance and grave signal suppression from other interfering substances in the bio-samples. In this research, a multiply-mesoporous hydrophilic TiO 2 nanohybrid (mM-TiO 2 @Cys) was synthesized by immobilizing Cys on a TiO 2 substrate with hierarchical mesopores to achieve the highly-performed enrichment of N-glycopeptides. With the advantages of superior hydrophilicity and multiply-mesoporous structure, the obtained material exhibited an excellent selectivity (IgG digests and BSA digests at the molar ratio of 1/500), a high sensitivity (1 fmol μL -1 for IgG digests) and a good size-exclusion ability (IgG digests, IgG and BSA at the molar ratio of 1/500/500) in the enrichment of N-glycopeptides from IgG digests. As a result, 281 N-glycopeptides corresponded with 109 glycoproteins were identified from 2 μL serum digests of the patients with nasopharyngeal carcinoma, and 181 N-glycopeptides corresponded with 78 glycoproteins were identified from 2 μL serum digests of the healthy volunteers, revealing the potential application value of mM-TiO 2 @Cys in glycoproteomics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Mass spectrometry (MS)-based glycoproteomics research requires additional sample pretreatment to improve the effective identification of low-abundance glycopeptides without interference from non-glycoproteins. Herein, an attractive strategy using resorcinol-formaldehyde (RF) resin and zirconium-based coordination polymer (Zr-BCP) was established to prepare one-dimensional porous coordination polymer composites for glycopeptide enrichment before MS analysis. The obtained Fe 3 O 4 @RF@Zr-BCP nanochains feature excellent magnetic response (42.26 emu/g), high hydrophilicity (16.0°), and large specific surface area (140.84 m 2 /g), which provides abundant affinity sites for specific capture of glycopeptides. The materials exhibit outstanding performance in the enrichment of glycopeptides in terms of sensitivity (15 fmol/μL IgG), selectivity (1:200, molar ratio of IgG/BSA), loading capacity (200 mg/g) and recovery (106.4 ± 3.5%). In addition, the developed method based on Fe 3 O 4 @RF@Zr-BCP has been successfully applied to capture glycopeptides in tryptic digest of mouse teratoma cell extracts. It is worth emphasizing that compared with dispersed nanoparticles, the one-dimensional chain structure brings extraordinary reusability to Fe 3 O 4 @RF@Zr-BCP nanochains, which is conducive to the rapid cyclic enrichment of glycopeptides. This present work provides a potential enrichment platform for comprehensive glycoprotein analysis, and opens a new avenue for the application of oriented-assembly nanochains., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Quantifying multiple biomarkers with high sensitivity in tiny biological samples is essential to meet the growing demand for point-of-care testing. This paper reports the development of a novel microfluidic device integrated with mass-producible micropillar array electrodes (μAEs) for multiple biomarker detections. The μAE are mass-fabricated by soft lithography and hot embossing technique. Pt-Pd bimetallic nanoclusters (BNC) are modified on the surface of μAEs by constant potential (CP)/multi-potential step (MPS) electrodeposition strategies to improve the electroanalytical performance. The experimental result displays that Pt-Pd BNC/μAEs have good sensitivity enhancement compared with bare planar electrodes and bare μAEs, the enhancement being 56.5 and 9.5 times respectively, from the results of the H 2 O 2 detection. Furthermore, glucose, uric acid and sarcosine were used as model biomarkers to show the biosensing capability with high sensitivity. The linear range and LOD of the glucose, uric acid and sarcosine detection are 0.1 mM-12 mM, 10 μM-800 μM and 2.5 μM-100 μM, 58.5, 3.4 and 0.4 μM, respectively. In particular, biosensing chips show wide linear ranges covering required detection ranges of glucose, uric acid and sarcosine in human serum, indicating the developed device has great potential in self-health management and clinical requirements., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The development of facilely synthetic materials acts an essential role in glycoproteome analysis, especially for the highly efficient enrichment of N-linked glycopeptides. In this work, a facile and timesaving route was introduced in which COF TP-TAPT served as a carrier and poly (ethylenimine) (PEI) and carrageenan (Carr) were successively coated on the surface via electrostatic interaction. The resultant COF TP-TAPT @PEI@Carr showed remarkable performance in glycopeptide enrichment with high sensitivity (2 fmol μL -1 ), high selectivity (1:800, molar ratio of human serum IgG to BSA digests), large loading capacity (300 mg g -1 ), satisfactory recovery (102.4 ± 6.0%) and reusability (at least eight times). Due to the brilliant hydrophilicity and electrostatic interactions between COF TP-TAPT @PEI@Carr and positively charged glycopeptides, the prepared materials could be applied in the identification and analysis in the human plasma of healthy subjects and patients with nasopharyngeal carcinoma. As a result, 113 N-glycopeptides with 141 glycosylation sites corresponding to 59 proteins and 144 N-glycopeptides with 177 glycosylation sites corresponding to 67 proteins were enriched from 2 μL plasma trypsin digests of the control groups and patients with nasopharyngeal carcinoma, respectively. 22 glycopeptides were identified only from the normal controls and 53 glycopeptides were detected only from the other set. The results demonstrated that this hydrophilic material was promising on a large scale and further N-glycoproteome research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Adenosine, as an endogenous nucleoside modulator, plays an important role in heart rate regulation, neurotransmission, and control of the respiratory system and thus it is significantly important to realize its sensitive detection. Herein, a highly sensitive electrochemical aptasensor for adenosine detection was proposed by using multi-walled carbon nanotubes (MWCNTs) as support matrix loading PtCu nanoparticles (PtCu-MWCNTs) to amplify signal. On one hand, disposable screen-printing gold electrodes (SPGEs) were used as superb sensing base to ensure the stable connection of aptamers 1 (ssDNA1). On the other hand, the PtCu-MWCNTs complex was synthesized through a one-pot method, which not only can precisely control the proportion of metal mass in the product but also exhibited superior electrocatalytic activity towards H 2 O 2 . The recognition reactions were achieved by stepwise incubation of ssDNA1, ssDNA2-PtCu-MWCNTs (denoted as ssDNA2-label), and adenosine on the SPGEs. As a result, the constructed electrochemical aptasensor exhibited a wide linear range from 10 nM to 1.0 μM with a low detection limit of 1.0 nM (S/N = 3) for adenosine detection. The aptasensor also successfully realized the adenosine detection in human serum samples, which means that the proposed aptasensor holds a potential application in point-of-care detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The construction of uniformly dispersed structure with abundant active sites is crucial for fast electron transport and advancing electrocatalytic reactions. Herein, Fe x Co y O 4 -rGO was prepared by depositing Fe and Co bimetallic oxides in-situ on reduced graphene oxide through a simple process combined hydrothermal reaction and calcination. Fe was elaborately introduced into the synthesis of metal oxides to alleviate the aggregation of cobalt oxides and obtain nanocomposites with homogeneously structured and abundant redox sites, and the bimetallic oxides nanomaterials had enhanced electrocatalysis under the synergistic effect. The flexible electrode prepared from Fe x Co y O 4 -rGO exhibited excellent detection performance for glucose with a detection limit down low to 0.07 μM and a sensitivity of 1510 μM cm -2  mA -1 . The adoption of flexible substrates improved the wearability of the electrode and broadened its practicality for detecting biomarkers on the skin surface. The constructed sensor was successfully used in the dynamic analysis of glucose content in tears, and the results were highly consistent with the test outcome of a commercial test kit, demonstrating its application prospects in non-invasive epidermal diabetes mellitus diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Natural products are rather complex samples containing a large number of compounds ranging from polar to nonpolar, small molecules to macromolecules, as well as numerous homologs/analogs with quite similar structures, which create great opportunities and treasures for discovery of bioactive drugs. For the purpose of better understanding the complex natural products and controlling their qualities, powerful analytical techniques for adequately separating chemical constituents and tracking potentially bioactive components are quite essential. Here, a design concept of bidirectional β-cyclodextrin (β-CD)-modified chromatographic stationary phase toward separation of bufadienolides extracted from toad is proposed. Bufadienolides could be divided into two classes: toad venom ligand (AAUBs) and toad toxin (AACBs) with remarkable differences in structures and polarity. The hydrophobic cavity of β-CD can encapsulate the steroid part of AACBs while the hydroxyls exposed on the β-CD surface have strong hydrophilic interactions with the arginine part of AACBs. Isothermal titration calorimetry and hydrogen nuclear magnetic resonance titration experiment further validate the rationality of this design. Furthermore, the β-CD-based stationary phase can be used as a hydrophilic material to construct a HILIC × RPLC 2D separation mode for the separation of AACBs, also works as a reverse phase material to construct a RPLC × RPLC 2D separation mode for the separation of AAUBs with good orthogonality. This study will open an avenue and provide a novel insight for high-efficiency two-dimensional separation of natural products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Protein glycosylation plays a vital role in many physiological activities in organisms. Due to the low abundance of glycopeptides and the interference of numerous non-glycopeptides in biological samples, selective enrichment of glycopeptides is of great significance for their successful identification. Metal organic frameworks (MOFs) materials are appropriate for glycopeptides enrichment by virtue of their large specific surface area and outstanding hydrophilic properties. However, the instability of hydrophilic MOFs in acidic solutions have severely limited their applications. In this work, a rational facile strategy was established to synthesize a stable hydrophilic hierarchical porous MOF (denoted as HP-MOF-Arg@mSiO 2 ). This new material improved the selectivity and sensitivity of enrichment for glycopeptides via modification of arginine groups. More importantly, the mesoporous silica layer was introduced to enhance the stability of MOFs in aqueous solution and achieve the size exclusion effect of large-size proteins in complex samples. Overall, owing to the unique hierarchical porous and the hydrophilic modification, the synthesized HP-MOF-Arg@mSiO 2 materials showed excellent hydrophilicity and hydrolytic stability, resulting in outstanding specific separation capacity in glycopeptides enrichment. A total of 521 and 342 glycopeptides were respectively captured from 2 μL human serum digests and mouse testis tissue digests, revealing the potential of the materials in the study of glycoproteomics in complex biological samples., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Considering the importance of glycopeptides in the clinical diagnosis of cancer and some serious diseases, the identification of glycopeptides from complex biological samples has attracted considerable attention. Effective pre-enrichment before mass spectrometry analysis plays an important role. In this work, a kind of hydrophilic two-dimensional composites (denoted as GO@MPDA@Arg) based on mesoporous polydopamine-graphene oxide were used to selectively enrich glycopeptides in biological samples. The mesoporous polydopamine (MPDA) layer self-assembled with template Pluronic F127 provided more binding sites to load arginine, and bound arginine enhanced the hydrophilicity of the material. As a result, GO@MPDA@Arg composites exhibited excellent enrichment performance for glycopeptides, containing good selectivity (IgG digests : BSA digests = 1:50, molar ratio), low detection limit for IgG digests (10 fmol μL -1 ), high loading capacity for IgG digests (200 μg mg -1 ), and good size exclusion (IgG digests : IgG : BSA = 1:100:100, mass ratio). In addition, mouse brain tissue was selected as the actual biological sample to further study the enrichment effect of GO@MPDA@Arg composites. In three parallel experiments, a total of 401 glycopeptides belonging to 233 glycoproteins were enriched from 200 μg digestion of mouse brain extract. The enrichment results demonstrate that GO@MPDA@Arg composites have application potential for glycopeptides enrichment in protein post-translational modification research., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Signal amplification is crucial to improve the sensitivity for the electrochemical detection of cardiac troponin I (cTnI), one of the ideal biomarkers for early acute myocardial infarction (AMI) diagnosis. Herein, we developed a novel signal amplification strategy to construct a sandwich-type electrochemical aptasensor for the detection of cTnI. Core-shell Pd@Pt dendritic bimetallic nanoparticles loaded on melamine modified hollow mesoporous carbon spheres (Pd@Pt DNs/NH 2 -HMCS) was prepared as labels to conjugate with thiol-modification DNA aptamers probe for signal amplification. While introducing numerous amino groups, the melamine functionalized hollow mesoporous carbon spheres (NH 2 -HMCS) retained the edge-plane-like defective sites for the adhesion and electrocatalytic reduction of H 2 O 2 . With the unique characteristics of NH 2 -HMCS, it not only enhanced the dispersity and loading capacity of core-shell Pd@Pt dendritic bimetallic nanoparticles (Pd@Pt DNs), but also improved the stability of bonding by the affinity interaction between Pd@Pt DNs and amino groups of melamine. Meanwhile, the synergistic catalysis effect between Pd@Pt DNs and NH 2 -HMCS significantly enhanced the electrocatalytic reduction of H 2 O 2 and further amplified the signal. Under optimal conditions, this recommended aptasensor for cTnI detection displayed a wide dynamic range from 0.1 pg/mL to 100.0 ng/mL and a low detection limit of 15.4 fg/mL (S/N = 3). The sensor also successfully realized the analysis of cTnI-spiked human serum samples, meaning potential applications in AMI diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The detection of circulating tumor DNA (ctDNA) has increasingly received a great deal of attention considering its significance in cancer diagnosis. And the signal amplification plays an important role in the development of sensitive ctDNA biosensors. Herein, the nanocomposites (denoted as HAC-AuPt), integrating from high-active carbon (HAC) and AuPt alloy nanoparticles, were synthesized and subsequently used as a signal amplification label to fabricate a sandwich-type ctDNA electrochemical biosensor. Characterizations demonstrated that HAC presents uniform size distribution and AuPt alloy nanoparticles were successfully loaded on HAC. The current response could be amplified to a great extent by the resultant HAC-AuPt due to its excellent electrochemical property. The nanocomposites were further bounded with DNA signal probes (SPs) via Au-S or Pt-S assembly to form SPs-label. After the capture probes (CPs) were immobilized on the electrode surface, the target DNA (tDNA) and SPs-label were stepwise incubated on the CPs-modified electrode, thus forming a sandwich-type structure. By monitoring the catalytic signal of HAC-AuPt towards the reduction process of H 2 O 2 , this biosensor provided a wide linear range of 10 -8  mol/L - 10 -16  mol/L with a low detection limit of 3.6 × 10 -17  mol/L (S/N = 3) for the detection of the tDNA. Furthermore, obvious differences in response signals among different DNAs were observed benefitting from the excellent selectivity of the biosensor. Besides, the long-term stability, reproducibility, and recovery rate were proved to be outstanding. These results indicate that the established biosensor holds a potential application in the clinical diagnosis of ctDNA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Glycosylation is one of the most important post-translational modifications of proteins, and plays an important role in the structure and function of proteins. However, due to the diversity of glycopeptide forms and their low abundance, it is extraordinarily challenging to capture and separate glycopeptides with high selectivity from complex biological samples with mass spectrometric analysis. Here, we synthesized a new type of hydrophilic composite based on electrostatic interactions, which has been proven to be effective in immobilizing cationic cellulose on graphene oxide-dopamine carriers (expressed as GO-DA-JR), for highly specific enrichment of N-glycopeptides. The introduction of cationic cellulose provides not only a perfect surface charge for the composite but also a greater ability to enrich glycosylated peptides. Thirty-two glycopeptides from human serum immunoglobulin G (IgG) tryptic digests were observed with a greatly improved signal-to-noise ratio (S/N) and also presented high performance in anti-interfering enrichment of glycopeptides from complex samples containing 100-fold bovine serum albumin tryptic digests. In addition, GO-DA-JR has higher sensitivity (1 fmol/μL IgG) and better enrichment capacity (up to 150 mg/g). Moreover, the results of glycopeptide enrichment and glycosylation analysis from human serum also show egood enrichment selectivity from real biological samples. This work exhibits high selectivity, high sensitivity, good stability and operability, indicating its potential for applications of glycopeptides enrichment in post-translational modification proteomics., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Glycosylation and phosphorylation are two of the most common and important post-translational modifications (PTMs) of proteins, which play critical roles in regulating a variety of complex biological processes and involvement in many diseases. Due to the low abundance of phosphopeptides and glycopeptides, highly selective enrichment methods are crucial to the identification of protein phosphorylation and glycosylation by mass spectrometry (MS). Here, monodisperse uniform Al 3+ -doping-TiO 2 mixed oxide microspheres were easily synthesized. The morphology was controlled by a sol-gel method, during the hydrothermal treatment. The obtained microspheres with uniform particle size distribution (about 1-2 μm)，high surface area and improved pore structures, were characterized by SEM, TEM, XRD and N 2 adsorption-desorption isotherms. Al 3+ -doping-TiO 2 was applied in enriching glycopeptides and phosphopeptides respectively or simultaneously by using different enrichment conditions, achieving selective enrichment of glycopeptides and phosphopeptides. 20 glycopeptides and 25 phosphopeptides enriched from the tryptic digest mixtures of human serum immunoglobulin G (IgG) and α-casein (molar ratio of 1:1) were obviously observed with greatly improved signal-to-noise (S/N) ratio. Meanwhile, the enrichment results of non-fat milk and human serum also show the enrichment selectivity from complex biological samples. This study will provide a novel insight for selective enrichment of glycopeptides and phosphopeptides in post-translational modification proteomics research., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A light-switchable transgene system called LightOn gene expression system could regulate gene expression with a high on/off ratio under blue light, and have great potential for spatiotemporally controllable gene expression. We developed a nanoparticle drug delivery system (NDDS) to achieve tumor microenvironment-responsive and targeted delivery of diphtheria toxin A (DTA) fragment-encoded plasmids to tumor sites. The expression of DTA was induced by exposure to blue light. Nanoparticles composed of polyethylenimine and vitamin E succinate linked by a disulfide bond, and PEGylated hyaluronic acid modified with RGD peptide, accumulated in tumor tissues and were actively internalized into 4T1 cells via dual targeting to CD44 and α v β 3 receptors. The LightOn gene expression system was able to control target protein expression through regulation of the intensity or duration of blue light exposure. In vitro studies showed that light-induced DTA expression reduced 4T1 cell viability and induced apoptosis. Furthermore, the LightOn gene expression system enabled spatiotemporal control of the expression of DTA in a mouse 4T1 tumor xenograft model, which resulted in excellent antitumor effects, reduced tumor angiogenesis, and no systemic toxicity. The combination of the LightOn gene expression system and NDDS may be an effective strategy for treatment of breast cancer., (© 2020 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.)

In this work, magnetic mesoporous silica microspheres (Mag-MSMs) with ordered radial mesochannels were fabricated by a self-assembly synthesis in chlorobenzene-water mixed system. Then, the obtained Mag-MSMs were modified with polyethyleneimine (PEI), phytic acid (PA) and Ti 4+ (denoted as Mag-MSMs@PEI-PA-Ti 4+ ) via layer by layer (LbL) assembly. Due to the excellent hydrophilicity of PEI and PA and the large amount of Ti 4+ , the Mag-MSMs@PEI-PA-Ti 4+ possessed combined properties of hydrophilic interaction liquid chromatography (HILIC)- and immobilized metal ion affinity chromatography (IMAC)-based materials, which could be used as a dual-purpose material for N-glycopeptides or phosphopeptides enrichment. The proposed Mag-MSMs@PEI-PA-Ti 4+ exhibited an outstanding performance for N-glycopeptides enrichment (selectivity: IgG/BSA = 1:1000; sensitivity: 0.5 fmol/μL IgG) and phosphopeptides enrichment (selectivity: α-casein/BSA=1:5000; sensitivity: 0.2 fmol/μL α-casein). Furthermore, after enrichment with Mag-MSMs@PEI-PA-Ti 4+ , a total of 276 N-glycopeptides assigned to 132 glycoproteins were identified from 2 μL human serum and 1645 phosphopeptides corresponding to 704 phosphoproteins were identified from 200 μg HeLa cell extracts., (Copyright © 2019 Elsevier B.V. All rights reserved.)

As pyrophosphate ion (PPi) and pyrophosphatase (PPase) play crucial roles in the pathological process of arthritis, determination of PPi and PPase in biological fluids turns to be of great importance for clinical diagnosis and therapy of arthritic diseases. In this work, we proposed a new fluorescent assay for PPi and PPase activity detection based on the competitive coordination chemistry of Fe 3+ between PPi and an in situ formed fluorescent polydopamine (PDA). FeCo layered double hydroxide (FeCo-LDH) was explored as a peroxidase mimic to facilitate the in situ formation of fluorescent PDA from dopamine mediated by low-concentration H 2 O 2 within 30 min; The formed fluorescent PDA could be significantly quenched by Fe 3+ through forming a PDA-Fe 3+ complex structure; When PPi existed, it coordinated Fe 3+ competitively against PDA and inhibited the fluorescence quenching of PDA by Fe 3+ ; When PPi was hydrolyzed under the catalysis of PPase, the Fe 3+ ion could quench the fluorescence of the formed PDA again. With these principles, our fluorescent assay was able to detect PPi and PPase activity specifically, providing detection limits down to 54 μM and 0.13 U/L, respectively. Furthermore, accurate determination of PPi and PPase activity in spiked human serum was also demonstrated using the developed assay., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this work, we presented a facile elution-free method for ultrasensitive enrichment of glycopeptides using two kinds of novel Ce-metal-organic frameworks (Ce-MOF) post-modified with hyaluronic acid (Ce-MOF@HA) and glutamic acid (Ce-MOF@Glu). Both of the synthesized materials remained stable in the loading buffer to enrich glycopeptides selectively and degrade in the eluent to release captured glycopeptides. Due to the dissolution of materials, the elution step of the enrichment process is omitted, resulting in an extremely high sensitivity (detection limit, 0.5 fmol/μL). Meanwhile, Ce-MOF@HA and Ce-MOF@Glu also possessed excellent selectivity with molar ratios of IgG and BSA digests being 1:1000 and 1:500, respectively. Noticeably, the practical applicability of the obtained materials was inspected by analyzing the glycopeptides enriched from human serum (2 μL) by nano-LC-MS, in which 434 N-glycopeptides from 182 N-glycoproteins (by Ce-MOF@HA) and 328 N-glycopeptides from 135 N-glycoproteins (by Ce-MOF@Glu) were detected, respectively. This work provides a new method to simplify the process of glycopeptides enrichment and also paves a novel way for the enrichment of trace targets from complex matrices., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The detection of superoxide anions (O 2 •- ) is widely considered as a potential way for cancer diagnosis and the development of enzyme-mimic catalysts is the main challenge in the establishment of electrochemical sensors for O 2 •- sensing in real samples. Here we present a novel enzyme- and metal-free electrochemical catalyst for superoxide (O 2 •- ) sensing based on the widely-used carbon nanotubes (CNT). Through a one-step hydrothermal process induced by phytic acid (PA), CNT-based porous foam (PACNTF) was successfully obtained. Characterizations demonstrated the enhanced defect and disorder degree of PACNTF after PA treatment, which leaded to the increased active sites of PACNTF for electron transfer and the adhesion of O 2 •- during the electrochemical process. As a result, the PACNTF presented higher conductivity and larger current response toward O 2 •- sensing when compared with CNT precursor and CNTF without PA treatment. The sensitivity of PACNTF/SPCE was calculated to be 1230 μA cm -2  mM -1 in the linear range of 0-193.6 μM (R 2  = 0.965) and 373 μA cm -2  mM -1 in the linear range of 193.6-1153.6 μM (R 2  = 0.995) with a limit of detection of 0.16 μM (S/N = 3). Further, the PACNTF/SPCE presented fast response toward cell-released O 2 •- stimulated by Zymosan A. The above results indicated that the fabricated sensor holds potential usage in biological samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this work, hollow magnetic macro/mesoporous TiO 2 nanoparticles (denoted as Fe 3 O 4 @H-fTiO 2 ) were synthesized by a facile "hydrothermal etching assisted crystallization" route to improve the phosphopeptide enrichment efficiency. The porous nanostructure of TiO 2 shell and large hollow space endowed the Fe 3 O 4 @H-fTiO 2 with a high surface area (144.71 m 2 g -1 ) and a large pore volume (0.52 cm 3 g -1 ), which could provide more affinity sites for phosphopeptide enrichment. Besides, the large pore size of TiO 2 nanosheets and large hollow space could effectively prevent the "shadow effect", thereby facilitating the diffusion and release of phosphopeptides. Compared with the hollow magnetic mesoporous TiO 2 with small and deep pores (denoted as Fe 3 O 4 @H-mTiO 2 ) and solid magnetic macro/mesoporous TiO 2 , the Fe 3 O 4 @H-fTiO 2 nanoparticles showed a better selectivity (molar ratio of α-casein/BSA up to 1:10000) and a higher sensitivity (0.2 fmol/μL α-casein) for phosphopeptide enrichment. Furthermore, 1485 unique phosphopeptides derived from 660 phosphoproteins were identified from HeLa cell extracts after enrichment with Fe 3 O 4 @H-fTiO 2 nanoparticles, further demonstrating that the Fe 3 O 4 @H-fTiO 2 nanoparticles had a high-efficiency performance for phosphopeptide enrichment. Taken together, the Fe 3 O 4 @H-fTiO 2 nanoparticles will have unique advantages in phosphoproteomics analysis., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Enzyme-free electrochemical detection of glucose in alkaline media with favorable properties has been acquired by fabricating a robust and large-surface sensing platform, which is composed of anneal-shrinked Cu 2 O dendrites grown on porous Cu foam. On the one hand, the good compatibility of electrodeposited Cu 2 O architectures and Cu foam substrate, together with a post-deposition anneal at 200°C, offers a mechanically stable interface for glucose determination. On the other hand, the macropores of Cu foam that is decorated with unique Cu 2 O dendrites provide large active surface for electrocatalytic reaction and mass transport. As a result, selective sensing of glucose in the linear concentration range of 0.001-1.4mM was achieved on the fabricated sensor, with a sensitivity of as high as 5.04mAcm -2 mM -1 and a detection limit of 0.13μM. Desired long-term performance stability was obtained, partially due to the strong adhesion of Cu 2 O microstructures to the Cu foam support after annealing. Practical monitoring of glucose in serum samples was also demonstrated on the proposed sensor., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Nanosized materials acting as substitutes of natural enzymes are currently attracting significant research due to their stable enzyme-like characteristics, but some flaws of these nanozymes, including their limited catalytic rate and efficiency, need to be remedied to enable their wider applications. In this work, we verify for the first time the catalytic behavior of uncapped nanobranch-based CuS clews as a peroxidase mimic. XRD, XPS, SEM, and TEM proofs demonstrate that high-purity CuS clews composed of intertwined wires with abundant nanodendrites outside are successfully produced via a facile one-pot hydrothermal synthesis approach, with thiourea as both the sulfion source and the structure-directing agent. The synthesized CuS can catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) by H 2 O 2 to trigger a visible color reaction with rapid response (reaching a maximum change within 5 min). The proposed CuS nanozyme exhibits preferable catalytic kinetics over natural horseradish peroxidase (HRP). This outstanding activity primarily results from the large surface area and rich sites exposed by the uncapped unique structure. Under optimized conditions, the fabricated sensing system provides linear absorbance (652 nm) changes in the H 2 O 2 concentration range of 0.2˜130 μM, with a detection limit of as low as 63 nM. When coupled with glucose oxidase (GOD), the system is demonstrated to be capable of monitoring glucose in blood samples with excellent performance., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A molecular probe of DibOH (2,6-bis(4-hydroxybenzylidene)cyclohexanone) designed as the ameliorant to the curcumin was prepared in which one enol unit was removed to avoid the intramolecular hydrogen bond and thus more rigidity and better coplanarity were achieved. Deprotonation of the phenolic hydroxyl group led to the negative charge and the intramolecular charge transfer (ICT) functioned accordingly. The DibOH probe in basic conditions exhibited the absorption peak at 468 nm, which indicated a red shift of 183 nm relative to that in acid conditions and was visible as a brown color to naked eyes. The ratio of fluorescence intensity at 612 nm to that at 520 nm (I612/I520) was calculated and a clear correlation with the pH value was obtained. The density functional theory (DFT) was performed on theoretical investigation of the acidic and basic forms of DibOH. The DibOH probe was evaluated in fluorescent imaging of human breast cancer cells (MCF-7) wherein the heterogeneous distribution of the intracellular pH microenvironment was observed., (Copyright © 2015 Elsevier B.V. All rights reserved.)

An interesting and novel method for the selective and sequential enrichment of singly- and multiply-phosphorylated peptides with a zwitterionic material "Click TE-Cys" is presented. Retention mechanisms between phosphopeptides and Click TE-Cys are systematically investigated by checking the influence of acetonitrile content, pH value, and buffer concentration on the retention of phosphopeptides. Both hydrophilic interaction and electrostatic interaction are involved in retention between phosphopeptides and Click TE-Cys. Based on these results, an optimized method is established for selective enrichment of phosphopeptides using Click TE-Cys. This method not only exhibits high selectivity for phosphopeptides, but also fractionates singly- and multiply-phosphorylated peptides into two fractions. This method was evaluated using relatively complex samples, including peptide mixtures of α-casein and bovine serum albumin (BSA) at a molar ratio of 1:10 and skim milk. This efficient and optimized protocol has great potential for enriching multiply-phosphorylated peptides and could be a valuable tool for specific enrichment of phosphopeptides in phosphoproteome analysis., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In the present work, a high-performance enzyme-based electrochemical sensor for the detection of superoxide anion radical (O2(●-)) is reported. Firstly, we employed a facile approach to synthesize PtPd nanoparticles (PtPd NPs) on chemically reduced graphene oxide (RGO) coated with polydopamine (PDA). The prepared PtPd-PDARGO composite was well characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. Then the assembled composite was used as a desired electrochemcial interface for superoxide dismutase (SOD) immobilization. Owing to the PDA layer as well as the synergistic effect of PtPd NPs, the fabricated SOD/PtPd-PDARGO sensor exhibited an outstanding sensitivity of 909.7 μA mM(-1) cm(-2) upon O2(●-) in a linear range from 0.016 mM to 0.24 mM (R(2)=0.992), with a low detection limit of 2 μM (S/N=3) and excellent selectivity, good reproducibility as well as favorable long-term stability., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The sluggish kinetic-controlled glucose oxidation reaction on Pt electrodes is well recognized as the most critical issue that blocks the development and commercialization of enzyme-free glucose sensors, and increasing attention is being focused on improving the analytical performances of these nonenzymatic sensors through exploring new Pt-based catalysts. In the present research, we synthesized novel Pt-Pd nanoflakes (Pt-Pd NFs) with three-dimensional architectures on a homemade screen-printed gold film electrode (SPGFE) substrate using a facile electrochemical deposition without any template, and further investigated the properties of the as-fabricated Pt-Pd NFs/SPGFE for enzymeless glucose detection. The results reveal that the proposed Pt-Pd nanostructure can provide preeminent electrocatalytic activity and excellent selectivity for enzyme-free glucose sensing under simulative physiological conditions, mainly attributing to its attractive structure, large active surface and appropriate applied potential. The resulting Pt-Pd NFs/SPGFE offers linear current responses for glucose with the concentration upper limit to 16 mM. The obtained sensitivity is calculated to be as high as 48.0 μA cm(-2) mM(-1) in the presence of 0.15 M chlorides ions, and practical applications for blood sample analysis are also demonstrated. The proposed Pt-Pd structure is considered as a great potential building block for the fabrication of nonenzymatic electrochemical glucose sensors., (Copyright © 2012 Elsevier B.V. All rights reserved.)