Network Clustering Revealed the Systemic Alterations of Mitochondrial Protein Expression

The mitochondrial protein repertoire varies depending on the cellular state. Protein component modifications caused by mitochondrial DNA (mtDNA) depletion are related to a wide range of human diseases; however, little is known about how nuclear-encoded mitochondrial proteins (mt proteome) changes under such dysfunctional states. In this study, we investigated the systemic alterations of mtDNA-depleted (ρ0) mitochondria by using network analysis of gene expression data. By modularizing the quantified proteomics data into protein functional networks, systemic properties of mitochondrial dysfunction were analyzed. We discovered that up-regulated and down-regulated proteins were organized into two predominant subnetworks that exhibited distinct biological processes. The down-regulated network modules are involved in typical mitochondrial functions, while up-regulated proteins are responsible for mtDNA repair and regulation of mt protein expression and transport. Furthermore, comparisons of proteome and transcriptome data revealed that ρ0 cells attempted to compensate for mtDNA depletion by modulating the coordinated expression/transport of mt proteins. Our results demonstrate that mt protein composition changed to remodel the functional organization of mitochondrial protein networks in response to dysfunctional cellular states. Human mt protein functional networks provide a framework for understanding how cells respond to mitochondrial dysfunctions

Carbon Nanotube Paper-Based Electroanalytical Devices

Here, we report on carbon nanotube paper-based electroanalytical devices. A highly aligned-carbon nanotube (HA-CNT) array, grown using chemical vapor deposition (CVD), was processed to form bi-layered paper with an integrated cellulose-based Origami-chip as the electroanalytical device. We used an inverse-ordered fabrication method from a thick carbon nanotube (CNT) sheet to a thin CNT sheet. A 200-layered HA-CNT sheet and a 100-layered HA-CNT sheet are explored as a working electrode. The device was fabricated using the following methods: (1) cellulose-based paper was patterned using a wax printer, (2) electrical connection was made using a silver ink-based circuit printer, and (3) three electrodes were stacked on a 2D Origami cell. Electrochemical behavior was evaluated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). We believe that this platform could attract a great deal of interest for use in various chemical and biomedical applications

A Smartphone-Based Automatic Measurement Method for Colorimetric pH Detection Using a Color Adaptation Algorithm

This paper proposes a smartphone-based colorimetric pH detection method using a color adaptation algorithm for point-of-care applications. Although a smartphone camera can be utilized to measure the color information of colorimetric sensors, ambient light changes and unknown built-in automatic image correction operations make it difficult to obtain stable color information. This paper utilizes a 3D printed mini light box and performs a calibration procedure with a paper-printed comparison chart and a reference image which overcomes the drawbacks of smartphone cameras and the difficulty in preparing for the calibration procedure. The color adaptation is performed in the CIE 1976 u’v’ color space by using the reference paper in order to stabilize the color variations. Non-rigid u’v’ curve interpolation is used to produce the high-resolution pH estimate. The final pH value is estimated by using the best-matching method to handle the nonlinear curve properties of multiple color patches. The experimental results obtained using a pH indicator paper show that the proposed algorithm provides reasonably good estimation of pH detection. With paper-printed accurate color comparison charts and smart color adaptation techniques, superior estimation is achieved in the smartphone-based colorimetric pH detection system for point-of-care application

TiO2 Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

Plasma electrolytic oxidation (PEO) has been used in the past as a useful surface treatment technique to improve the anticorrosion properties of Mg alloys by forming protective layer. Coatings were prepared on AZ31 magnesium alloy in phosphate electrolyte with the addition of TiO2 nanoparticles using plasma electrolytic oxidation (PEO). This present work focuses on developing a TiO2 functional coating to create a novel electrophotocatalyst while observing the surface morphology, structure, composition, and corrosion resistance of the PEO coating. Microstructural characterization of the coating was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) followed by image analysis and energy dispersive spectroscopy (EDX). The corrosion resistance of the PEO treated samples was evaluated with electrochemical impedance spectroscopy (EIS) and DC polarization tests in 3.5 wt.% NaCl. The XRD pattern shows that the components of the oxide film include Mg from the substrate as well as MgO and Mg2TiO4 due to the TiO2 nanoparticle addition. The results show that the PEO coating with TiO2 nanoparticles did improve the corrosion resistance when compared to the AZ31 substrate alloy

In Vitro Cytotoxicity of Possible Corrosion Products from Mg-Based Biodegradable Metals: Magnesium Oxide and Magnesium Hydroxide Nanoparticles

Biodegradable magnesium (Mg) alloys have potential applications in orthopedic implants due to their mechanical and osseointegration properties. However, the surface characteristics, biocompatibility, and toxicity of the released corrosion products in the form of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2) nanoparticles (NPs) at the junction of implants and in the surrounding tissue are not completely understood. Here, we investigated in vitro cytotoxicity and morphological changes in human fetal osteoblast (hFOB) 1.19 cells in response to various concentrations (1 mM, 5 mM, 10 mM, and 50 mM) of MgO/Mg(OH)2 NPs by live/dead assay and scanning electron microscopy (SEM). In this study, we performed a surface characterization of MgO/Mg(OH)2 NPs to evaluate the size of the NPs. Further, an immersion test was performed in Dulbecco’s Modified Eagle’s Medium (DMEM) with randomly selected various concentrations (1 mM, 5 mM, 10 mM, 50 mM, and 100 mM) of MgO/Mg(OH)2 NPs to understand the degradation behavior of the NPs, and the change in the pH values from days 1 to 7 was measured. After conducting an immersion test for seven days, the highest concentration (100 mM) of MgO/Mg(OH)2 NPs was selected to study the element depositions on nanoparticles through scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX) mapping. The results from this in vitro cytotoxicity study suggest that less than or equal to 5-mM concentrations of MgO/Mg(OH)2 NPs are tolerable concentrations for hFOB 1.19 cells. This study provides a foundational knowledge of MgO/Mg(OH)2 NP cytotoxicity in hFOB 1.19 cells that can help to develop future sustainable biodegradable magnesium-based alloys for orthopedic applications

Assessment of Cytotoxicity of Magnesium Oxide and Magnesium Hydroxide Nanoparticles using the Electric Cell-Substrate Impedance Sensing

Magnesium (Mg)-based alloys have the potential for bone repair due to their properties of biodegradation, biocompatibility, and structural stability, which can eliminate the requirement for a second surgery for the removal of the implant. Nevertheless, uncontrolled degradation rate and possible cytotoxicity of the corrosion products at the implant sites are known current challenges for clinical applications. In this study, we assessed in vitro cytotoxicity of different concentrations (0 to 50 mM) of possible corrosion products in the form of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2) nanoparticles (NPs) in human fetal osteoblast (hFOB) 1.19 cells. We measured cell proliferation, adhesion, migration, and cytotoxicity using a real-time, label-free, non-invasive electric cell-substrate impedance sensing (ECIS) system. Our results suggest that 1 mM concentrations of MgO/Mg(OH)2 NPs are tolerable in hFOB 1.19 cells. Based on our findings, we propose the development of innovative biodegradable Mg-based alloys for further in vivo animal testing and clinical trials in orthopedics

Three-dimensional brain-on-chip model using human iPSC-derived GABAergic neurons and astrocytes: Butyrylcholinesterase post-treatment for acute malathion exposure.

Organophosphates (OPs) induce acute and chronic neurotoxicity, primarily by inhibiting acetylcholinesterase (AChE) activity as well as by necrosis, and apoptosis. Butyrylcholinesterase (BuChE), an exogenous bioscavenger of OPs, can be used as a treatment for OP exposure. It is prerequisite to develop in vitro brain models that can study BuChE post-treatment for acute OP exposure. In this study, we developed a three-dimensional (3D) brain-on-chip platform with human induced pluripotent stem cell (iPSC)-derived neurons and astrocytes to simulate human brain behavior. The platform consists of two compartments: 1) a hydrogel embedded with human iPSC-derived GABAergic neurons and astrocytes and 2) a perfusion channel with dynamic medium flow. The brain tissue constructs were exposed to Malathion (MT) at various concentrations and then treated with BuChE after 20 minutes of MT exposure. Results show that the iPSC-derived neurons and astrocytes directly interacted and formed synapses in the 3D matrix, and that treatment with BuChE improved viability after MT exposure up to a concentration of 10-3 M. We conclude that the 3D brain-on-chip platform with human iPSC-derived brain cells is a suitable model to study the neurotoxicity of OP exposure and evaluate therapeutic compounds for treatment