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A sensitive electrochemical sensor based on bovine serum albumin (BSA)/poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene nanosheets (PDDA-G) composite film modified glassy carbon electrode (BSA/PDDA-G/GCE) had been developed to investigate the oxidative protein damage and protections of protein from damage by flavonoids. The performance of this sensor was remarkably improved due to excellent electrical conductivity, strong adsorptive ability, and large effective surface area of PDDA-G. The BSA/PDDA-G/GCE displayed the greatest degree of BSA oxidation damage at 40 min incubation time and in the pH 5.0 Fenton reagent system (12.5 mM FeSO 4 , 50 mM H 2 O 2 ). The antioxidant activities of four flavonoids had been compared by fabricated sensor based on the relative peak current ratio of SWV, because flavonoids prevented BSA damage caused by Fenton reagent and affected the BSA signal in a solution containing Co(bpy) 3 3 + . The sensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). UV–vis spectrophotometry and FTIR were also used to investigate the generation of hydroxyl radical and BSA damage, respectively. On the basis of results from electrochemical methods, the order of the antioxidant activities of flavonoids is as follows: (+)-catechin > kaempferol > apigenin > naringenin. A novel, direct SWV analytical method for detection of BSA damage and assessment of the antioxidant activities of four flavonoids was developed and this electrochemical method provided a simple, inexpensive and rapid detection of BSA damage and evaluation of the antioxidant activities of samples. [ABSTRACT FROM AUTHOR]

Leptin is a vital biomarker of non-alcoholic fatty liver (NAFLD), and its evaluation of the concentration level in vivo is of great significance to NAFLD diagnosis. Therefore, it is pressing to develop a method for rapid and sensitive detection of leptin. This paper describes an environmentally friendly and label-free immunosensor based on porous graphene functionalized black phosphorus (PG-BP) composite to detect of leptin. The PG-BP was synthesized via strong coherent coupling between porous graphene (PG) surface plasmons and anisotropic black phosphorus (BP) localized surface plasmons, which made the electrochemical performance of PG and BP synergistic as well as increased the stability and conductive capability of BP material. The PG-BP modified electrodes was further prepared by gold nanoparticles, cysteamine, and glutaraldehyde in turn. Due to the cross-linking effect of glutaraldehyde, anti-leptin can be firmly fixed. These properties of the platform improved the conductive capability of the immunosensor and enhanced the load capacity of the proteins, thereby, the sensitivity of the immunosensor was significantly increased. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range of 0.150–2500 pg/mL with a low detection limit of 0.036 pg/mL. The leptin immunosensor displayed excellent selectivity and anti-interference ability, which could be used for early screening and diagnosis of clinical NALFD. • A BSA/anti-leptin/Glu/Cys/AuNPs/PG-BP/GCE immunosensor was successfully fabricated. • The proposed immunosensor was successfully used for the detection of leptin with a wide range of detection and low detection limits. • The immunosensor can be used for the sensitive, efficient and real-time analysis of leptin in real samples. • The immunosensor is expected to provide a reliable, real-time and convenient method for clinical trials of NAFLD markers. [ABSTRACT FROM AUTHOR]

A pectic polysaccharide (named as CPP1c) extracted from Codonopsis pilosula was evaluated for its structural features and potential of immune-modulating activities in an aging mouse model of senescence accelerated mouse prone 8 (SAMP8) in vitro and in vivo . The relative molecular weight and the absolute molecular weight of CPP1c were 1.26 × 10 5 Da and 1.49 × 10 5 Da, respectively. Investigation of structural features by a combination of chemical and instrumental analysis showed CPP1c was composed of →1)-α- l - R ha p -(2,4→, →1)-α- l -Ara f -(5→, →1)-α- d -Gal p -(6→ and →1)-α- d -Gal p A-(4→ in a molar ratio of 3:1:2:33. CPP1c could promote lymphocyte proliferation, modulate the percentage of CD4 + , CD8 + , CD28 + and CD152 + T cells and enhance the production of IL-2, TNF-α and IFN-γ. Moreover, PCR assay revealed CPP1c augmented the expressions of CD28, PI3 K and p38MAPK mRNA, and the increase of protein expressions of the same genes was also confirmed by western blot analyses. In addition, CPP1c had the potential of promoting the homing of lymphocytes. Taking all factors into consideration, we deduced CPP1c might exert its immunostimulating potency via promoting T cell activation by TCR/CD28 signaling pathways. [ABSTRACT FROM AUTHOR]

Four novel Salan Hf(IV) complexes stabilized by 2,6-dipicolinic acid (Dipic) were synthesized and characterized by 1H, 13C NMR and X-ray diffraction spectroscopy. These Hf(IV) bis -chelates could be obtained in good to excellent yields (88%–91%) and demonstrated rather good stability in aqueous media and on silica gel. [L 2 Hf (IV) Dipic 4-H,Cl ] containing steric bulk L 2 were stable in about 10% H 2 O (H 2 O/THF (v/v)), however, [L 1 Hf (IV) Dipic 4-H,Cl ] with non-steric L 1 could slowly dissociate and release nontoxic L 1. [L 1 – 2 Hf (IV) Dipic 4-Cl ] showed excellent anti-tumoral activity in the range of cisplatin (Hela S3: IC 50 = 3.5 ± 0.4 μM, Hep G2: IC 50 = 11.2 ± 2.1 μM). In addition, the cellular uptake and apoptosis investigation of [L 1 Hf (IV) Dipic 4-Cl ] suggested a fast cellular uptake process against Hela S3 cells with an almost exclusive induced apoptosis cell death path. Novel [SalanHf (IV) Dipic] demonstrate potent anti-tumoral activity and stability with rapid cellular uptake and exclusive induced Hela S3 cell apoptotic death. [Display omitted] • Salan Hf(IV) bis -chelated complexes demonstrated excellent anti-tumoral activity in the range of cisplatin. • Salan Hf(IV) bis -chelated complexes exhibit a fast cellular uptake and an almost exclusive induced Hela S3 cell apoptosis. • The Hf(IV) complexes bearing steric demanding Salan exhibit both good stability and anti-tumoral activity. • Salan Hf(IV) bis -chelated complexes demonstrate good selectivity to tumor cells. [ABSTRACT FROM AUTHOR]