Construction of nanozyme based with mixed valence manganese oxide loaded on defective metal-organic frameworks for sensitive detection of biomarker procalcitonin.

Nanozymes possess the advantages of high stability, adjustable catalytic activity and simple preparation processes, which position them as a promising alternative to natural enzymes. In this work, an oxidase-like nanozyme has been prepared by loading mixed valence manganese oxides (MnO) on defective PCN-224 MOFs (dPCN). Dodecanoic acid was utilized to introduce abundant mesoporous defects into the dPCN, allowing manganese oxide to grow in situ on the surface and within the pores.

Development of dual-enhancer biocatalyst with photothermal property for the degradation of cephalosporin.

The abuse of cephalosporins poses a serious threat to human health and the ecological environment. In this work, cephalosporinase (AmpC enzyme) and Prussian blue (PB) crystals were encapsulated into ZIF-8 metal-organic frameworks (MOFs), and a photothermal AmpC/PB@ZIF-8 MOFs (APZ) nanocatalyst was prepared for the catalytic degradation of cephalosporin. The temperature of the APZ catalytic degradation system can be regulated by irradiation with near infrared light due to the photothermal effect of PB, and then, the activity of the APZ biocatalyst is significantly enhanced.

Development of dual-ligand titanium (IV) hydrophilic network sorbent for highly selective enrichment of phosphopeptides.

A hydrophilic metal-organic network based on Ti and dual natural ligand, tannic acid (TA) and phytic acid (PA), has been developed to enrich phosphopeptides from complex bio-samples prior to liquid chromatography-mass spectrometric analysis. Due to the strong chelation ability of TA and PA, abundant Ti can be immobilized in the material, forming hydrophilic network by one-step coordination-driven self-assembly approach. The sorbent, TA-Ti-PA@FeO, exhibited satisfactory selectivity for the phosphopeptides in the tryptic digest of β-casein, and can eliminate the interference components in 1000-fold excess of bovine serum albumin.

Biodegradation pathway of penicillins by β-lactamase encapsulated in metal-organic frameworks.

The pollution caused by the abuse of antibiotics has posed a serious threat to the ecological environment and human health, so development of effective strategies for degradation and disposal of antibiotic residues is urgently needed. In this work, penicillinase, a kind of β-lactamase, was immobilized into zeolitic imidazolate framework-8 (ZIF-8) by self-assembly method and the catalytic performance of the β-lactamase@ZIF-8 porous materials for degradation of penicillins has been investigated by high performance liquid chromatography coupled with mass spectrometry. The results illustrated that the catalytic activity of the encapsulated enzyme was significantly enhanced comparing with that of free enzyme.

Fluorescence Resonance Energy Transfer-Mediated Immunosensor Based on Design and Synthesis of the Substrate of Amp Cephalosporinase for Biosensing.

The traditional enzyme-linked immunosorbent assay (ELISA) has some disadvantages, such as insufficient sensitivity and low stability of the labeled enzyme, which limit its further applications. In this study, a more stable enzyme, Amp cephalosporinase (AmpC), was selected as the labeled enzyme, and its substrate was designed and synthesized. This substrate contained the cephalosporin ring core as the enzymatic recognition section and the structural motif of the 3-hydroxyflavone (3-HF) as the reporter molecule.

Label-Free Sandwich Imaging Ellipsometry Immunosensor for Serological Detection of Procalcitonin.

Analysis of trace low molecular weight (LMW) proteins in serum using the label-free imaging ellipsometry (IE) immunosensor is still a challenge due to the lack of an effective signal amplification strategy and the serious nonspecific adsorption. Herein we have developed a sandwich strategy-mediated IE (SSIE) immunosensor to enable the immunodetection of LMW protein biomarkers in serum samples. We have first found that the weak binding affinity and the insufficient surface amount density of the ligand are two important factors which hinder the detection of LMW proteins in serum using the IE immunosensor.

Enzyme-Free Amplification Strategy for Biosensing Using Fe-Poly(glutamic acid) Coordination Chemistry.

In this work, we outline a signal amplification strategy using the coordination chemistry between Fe and poly(glutamic acid) (PGA) for biosensing applications. The theoretical calculation based on density functional theory shows that PGA has a much higher binding affinity with Fe than the other metal ions. Guided by this rationale, we prepare a PGA-mediated signal probe through conjugating PGA onto polystyrene (PS) nanoparticles to form a brushlike nanostructure for Fe coordination.

Spectroscopic investigation of the interaction between human serum albumin and three organic acids.

The interactions of human serum albumin (HSA) with sinapic acid (SA), gallic acid (GA) and shikimic acid (SI) were investigated by fluorescence and Fourier transformed infrared spectrometry. Fluorescence results showed that one molecule of protein combined with one molecule of GA at the molar ratio of drug to HSA ranging from 0.1 to 30, and their binding constant (K(A)) is 1.

Interactions of human serum albumin with chlorogenic acid and ferulic acid.

The interactions of chlorogenic acid and ferulic acid with human serum albumin (HSA) have been investigated by fluorescence and Fourier transformed infrared (FT-IR) spectrometry. Fluorescence results showed that one molecule of protein combined with one molecule of drugs at the molar ratio of drug to HSA ranging from 1 to 10, and their binding affinities (KA) are 4.37 x 10(4) M(-1) and 2.

Studies on the interaction of total saponins of panax notoginseng and human serum albumin by Fourier transform infrared spectroscopy.

Total saponins of panax notoginseng (TPNS), isolated from the roots of panax notoginseng (Burk) F.H. Chen, have been considered as the main active components of San-Chi and have various therapeutical actions.

[Influence of solvents on IR spectrum of aromatic amines].

21 aromatic amines in different solution system are studied by FTIR. The IR spectra of these aromatic amines are greatly influenced by solvents. The IR stretching frequency of amino group in benzene has a larger bathochromic shift than that in tetrachloromethane (CCl4).

Studies on the hydrogen bonding of aniline's derivatives by FT-IR.

The hydrogen bonding of 23 aniline's derivatives in various solvents and in solid states are studied by Fourier transform infrared spectroscopy. The Infrared absorption of their amino group is greatly influenced by solvents. Compared with those data determined in hexane, the symmetric stretching frequency (nu(s)) and asymmetric stretching frequency (nu(as)) of amino group have an obvious bathochromic shift in benzene, but a relatively smaller shift in CCl4.