Integrated paper-based 3D platform for long-term cell culture and in situ cell viability monitoring of Alzheimer's disease cell model.

Reactive oxygen species including superoxide anion, hydrogen peroxide (H2O2) and hydroxyl radicals, as a conflicting class of biological metabolites in living organism, act crucial effect on Alzheimer's disease (AD). In this work, a facile integrated platform composed of a paper-based three-dimension (3D) cell culture system and an electrochemical sensor was developed for the construction of AD cell model in third dimensional structure and in situ cell viability monitoring by H2O2 released from PC12 cells cultured on paper scaffold were divided into three groups containing control group, amyloid beta peptide 25-35 (Aß25-35) group and Aß25-35+curcumin (Aß25-35+cur) group, respectively. In addition, the paper-based 3D platform displayed excellent properties, such as sensitivity, selectivity, reproducibility and stability. The levels of H2O2 expressed in PC12 cells of the three groups were monitored through a paper-based 3D platform. The viability of cells cultured on the 96-well plate was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Results of this paper-based platform are consistent with those of MTT, both displaying improved cell viability and decreased H2O2 production in Aß25-35+cur group compared to Aß25-35 group, which indicates that curcumin has effective cytoprotection. The paper-based 3D platform provides a convenient, economic and universal platform for in situ cell activity monitoring by key small molecules released from living cells.

Paper-based 3D culture device integrated with electrochemical sensor for the on-line cell viability evaluation of amyloid-beta peptide induced damage in PC12 cells.

In this communication, a paper-based 3D cell culture device integrated with electrochemical biosensor was applied to on-line monitoring of dopamine release from PC12 cell damage models induced by amyloid-beta peptide (Aß25-35) and cell intervene models protected by curcumin (Cur) and marrow mesenchymal stem cells (MSC) supernatant. The adhesion and proliferation of PC12 cells cultured on the paper scaffold was characterized by scanning electron microscopy and laser scanning confocal microscopy, which verify unique biocompatibility and 3D microarchitecture similar to human body microenvironment of paper substrate, so an artificial model simulating 3D microenvironment in vivo was constructed easily. The PC12 cells in paper-based devices consisted of four groups containing control group, Aß25-35 group, Aß25-35+Cur group and Aß25-35+MSC supernatant group. Under optimal conditions, this proposed device displayed a wide linear range from 0.05 to 1 µmol/L with a detection limit of 0.009 µmol/L (S/N = 3) and exhibited high sensitivity, good selectivity and excellent reproducibility. Furtherly, electrochemcial analysis and MTT assay gave a clue that the cell viability of Aß25-35+MSCs supernatant group was higher than that of Aß25-35+Cur group. Therefore, the detachable paper-based 3D device paves the way to a direct detection of exocytosis DA from neuron cells for on-line cell viability evaluation of neurodegenerative disease cell damage models.

Effects of cake collapse caused by deposition of fractal aggregates on pressure drop during ceramic filtration.

A cake collapse model was developed by taking the combined effects of fractal dimension, relaxation ratio, coordination number, and aggregate diameter into consideration. The cake porosity including intraaggregate and interaggregate porosities was modeled successively by three typical coordination numbers (n = 6, 8, and 12). Accordingly, an inversion method made it possible to deduce the coordination number using the measured cake porosities, and the reverse-calculated value with minimum error and the corresponding relaxation ratios were applied as the parameters for the model. As a result, the profiles of intraaggregate and interaggregate porosities and cake porosity were respectively predicted in contrast to the integrated variation of the relaxation ratio and the fractal dimension. Furthermore, a comparison between the model predictions of the cake pressure drop gradients with and without aggregate compression was conducted to validate the presence of cake collapse. The results show that the predictions based on the proposed collapse model are in agreement with the experiments, and the coordination number is one of the key factors that must be incorporated into the cake collapse models.

[Correlation between phonetically balanced maximum and pure tone auditory threshold among 106 auditory neuropathy patients].

OBJECTIVE: To estimate correlation between phonetically balanced maximum (PB max) and pure tone auditory threshold in auditory neuropathy (AN) patients. METHODS: One hundred and six AN patients were identified using multiple criteria including PB max, a metric for speech recognition, pure tone auditory threshold, acoustic emission test, distortion products otoacoustic emission (DPOAE) and auditory brainstem response (ABR). SPSS statistical software was used to estimate the Pearson's correlation between PB max and pure tone auditory threshold and to test whether pure tone auditory threshold, or auditory configuration had a significant impact on PB max. RESULTS: Even the patients had the same or similar values for pure tone auditory threshold or auditory configuration, varied values of PB max were found in two hundreds and twelve ears for 106 patients. Analysis of the data for 106 patients revealed a negative correlation (r = -0. 602, P <0. 01) between PB max and pure tone auditory threshold, i. e. hearing loss at a mild relates to a lower PB max. By using analysis of variance (ANOVA) method, it was found that both pure tone auditory threshold and auditory configuration had a significant (P <0.01) impact on the patients' PB max. CONCLUSIONS: This analysis implicated the promise and potential of pure tone auditory threshold and auditory configuration for predicting PB max of the AN patients, and improving the diagnosis of AN.