Cell viability analysis of Toxocara cati larvae with LIVE / DEAD® Viability/Cytotoxicity kit

Gallic acid functionalized silk fibroin/gelatin composite wound dressing for enhanced wound healing

As the incidence of chronic wounds increases, the requirements for wound dressings are rising. The specific aim of this study is to propose a novel gallic acid (GA) functionalized silk fibroin (SF) and gelatin (Gel) composite wound dressing in which GA is used as an antibacterial and wound healing substance. Via electrospinning, SF, Gel, and GA mixed solutions could be conveniently fabricated into a composite nanofiber mat (SF-Gel-GA), consisting of uniform fibers with an average diameter around 134.57 ± 84 nm. The internal mesh structure of SF-Gel-GA provides sufficient drug loading capacity, proper moisture permeability, and proper degradation rate. SF-Gel-GA presents excellent biocompatibility. NIH-3T3 fibroblast cells could adhere and spread stably on the SF-Gel-GA surface with slightly promoted proliferation. In the presence of SF-Gel-GA, the growth of both Gram-positive and Gram-negative bacteria, includingStaphylococcus aureusandPseudomonas aeruginosa, is significantly inhibited in both plate and suspension cultures. A cutaneous excisional mouse wound model proves the efficient ability of SF-Gel-GA to promote wound healing. Compared with pure SF dressing and commercial Tegaderm Hydrocolloid3Mdressing, the wound closure rate with SF-Gel-GA treatment is significantly improved. The histological assessments further demonstrate SF-Gel-GA could facilitate collagen deposition, neovascularization, and epithelialization at wound sites to promote wound healing. In conclusion, a novel SF-Gel-GA composite wound dressing with efficient wound healing activities have been developed for chronic wound treatment with broad healing potential.

Velvet antler polypeptide combined with calcium phosphate coating to protect peripheral nerve cells from oxidative stress

Functionalizing biomaterial substrates with biological signals shows promise in regulating cell behaviors through mimicking cellular microenvironment. Calcium phosphate (CaP) coating is an excellent carrier for immobilizing biological molecules due to its non-toxicity, good biocompatibility, biodegradability, and favorable affinity to plenty of molecules. In this study, we reported the adhesion, the viability and proliferation behaviors after oxidative stress injury of Schwann cells RSC96 on CaP immobilized with the Velvet Antler Peptide (VAP) isolated from velvet antler through coprecipitation process in modified Dulbecco's phosphate-buffered saline (DPBS) containing VAP. This approach provided well retention of functional molecules up to 28 days, and supported the adhesion and proliferation of RSC96 after oxidative stress injury without cytotoxicity. The simple and reproducible method of coprecipitation suggests that CaP is an ideal carrier to functionalize materials with biological molecules for peripheral nerve repair-related applications.

Cetylpyridinium chloride inhibits human breast tumor cells growth in a no-selective way

OBJECTIVE

Analyze the antitumor capacity of cetylpyridinium chloride (CPC) on human breast tumor cells, and the possible action mechanism.

MATERIAL AND METHODS

The human breast tumor cells MCF-7 and no-tumor breast cells MCF-10A were exposed to CPC under various condition (concentration and duration). Cell viability was measured with MTT assay, the LIVE/DEAD assay, and fluorescence microscopy. Membrane permeability after CPC exposure was evaluated by Calcein AM assay, mitochondrial morphology with a MitoView staining, and genotoxicity with the comet assay and fluorescence microscopy.

RESULTS

CPC was cytotoxic to both MCF-7 and MCF-10A as of a 24-h exposure to 0.1 µM. Cytotoxicity was dose-dependent and reached 91% for MCF-7 and 78% for MCF-10A after a 24-h exposure to 100 µM CPC, which outperformed the positive control doxorubicin in effectiveness and selectivity. The LD50 of CPC on was 6 µM for MCF-7 and 8 µM for MCF-10A, yielding a selectivity index of 1.41. A time response analysis revealed 64% dead cells after only 5 min of exposure to 100 µM CPC. With respect to the action mechanisms, the comet assay did not reveal genome fragmentation. On the other hand, membrane damage was dose-dependent and may also affect mitochondrial morphology.

CONCLUSION

Cetylpyridinium chloride inhibits MCF-7 cell growing in a non-selective way as of 5 min of exposure. The action mechanism of CPC on tumor cells involves cell membrane damage without change neither mitochondrial morphology nor genotoxicity.

Modified Low-Temperature Extraction Method for Isolation of Bletilla striata Polysaccharide as Antioxidant for the Prevention of Alzheimer's Disease

Amyloid-β (Aβ) peptides play a key role in Alzheimer's disease (AD), the most common type of dementia. In this study, a polysaccharide from Bletilla striata (BSP), with strong antioxidant and anti-inflammatory properties, was extracted using a low-temperature method and tested for its efficacy against AD, in vitro using N2a and BV-2 cells, and in vivo using an AD rat model. The characterization of the extracted BSP for its molecular structure and functional groups demonstrated the effectiveness of the modified method for retaining its bioactivity. In vitro, BSP reduced by 20% reactive oxygen species (ROS) levels in N2a cells (p = 0.0082) and the expression levels of inflammation-related genes by 3-fold TNF-α (p = 0.0048), 4-fold IL-6 (p = 0.0019), and 2.5-fold IL-10 (p = 0.0212) in BV-2 cells treated with Aβ fibrils. In vivo, BSP recovered learning memory, ameliorated morphological damage in the hippocampus and cortex, and reduced the expression of the β-secretase protein in AlCl3-induced AD rats. Collectively, these findings demonstrated the efficacy of BSP for preventing and alleviating the effects of AD.

Cryptosporidium spp. and Giardia spp. (oo)cysts as target-organisms in sanitation and environmental monitoring: A review in microscopy-based viability assays

Cysts and (oo)cysts are the infective forms of parasitic protozoa, as Giardia and Cryptosporidium, which are widespread and associated to worldwide waterborne diseases outbreaks. These microorganisms pose a challenge to public health, as they are resistant to conventional disinfection methods, which make them important parameters when evaluating inactivation efficiency. However, when (oo)cysts are targets, it is challenging to infer inactivation efficacy, as it may require infectivity tests that are not often an option for laboratory routine analysis. In this scene, (oo)cyst viability based on induced excystation, membrane integrity and enzyme activity evaluated by dye inclusion and/or exclusion, as well as fluorescence reduction consist on microscopy-based techniques that may be options to estimate inactivation in the environmental context. This scoping review presents applications, advantages and limitations of these methodologies for viability assessment, in order to shed light on the (oo)cyst viability topic and provide insight strategies for choosing protocols in the environmental and sanitation field, in laboratory applications and novel research.

Improvement of ferrous ion-dependent nitrate removal (FeNiR) process with chelating ferrous ion as substrate

In order to improve the ferrous ion-dependent nitrate removal (FeNiR) process, hexametaphosphate chelated ferrous ion was used as substrate to replace the free ferrous ion. With hexametaphosphate chelated ferrous ion as substrate, the influent pH was adjusted to 6.8, and as a result a higher effluent pH (7.2) was detected. The volumetric removal rate (VRR) of nitrate kept at 0.42 ± 0.03 kg-N/(m³∙d) for 48 days and the corresponding nitrogen removal efficiency was 94.39 ± 4.57%. After 88 days of cultivation, FeNiR granules became small because of the oligotrophic substrate. The transmission electron microscope (TEM) analysis showed that less iron encrustation was formed on the surface or in the periplasm of FeNiR cells. The linear curve of the living cell percentage versus time showed that the death rate of FeNiR cells with chelated ferrous ion as substrate was much lower than that with free ferrous ion as substrate (0.4210 vs 0.9221). Without iron encrustation, both the FeNiR activity and alkaline phosphatase (ALP) activity of FeNiR cells kept at high level and thus the efficiency of the FeNiR reactor kept stable and high. With hexametaphosphate chelated ferrous ion as substrate, the pH in bulk liquid was high (pH = 7.2) resulting in the high FeNiR rate, and less iron encrustation was formed around cells ensuring the stability of high FeNiR rate. Therefore, using hexametaphosphate chelated ferrous ion as substrate was an efficient way to improve the FeNiR process.