Colorectal Adenocarcinoma Cell Culture in a Microfluidically Controlled Environment with a Static Molecular Gradient of Polyphenol

Heparin-Functionalized Bioactive Glass to Harvest Endogenous Growth Factors for Pulp Regeneration

Pulp and periapical diseases can lead to the cessation of tooth development, resulting in compromised tooth structure and functions. Despite numerous efforts to induce pulp regeneration, effective strategies are still lacking. Growth factors (GFs) hold considerable promise in pulp regeneration due to their diverse cellular regulatory properties. However, the limited half-lives and susceptibility to degradation of exogenous GFs necessitate the administration of supra-physiological doses, leading to undesirable side effects. In this research, a heparin-functionalized bioactive glass (CaO-P2O5-SiO2-Heparin, abbreviated as PSC-Heparin) with strong bioactivity and a stable neutral pH is developed as a promising candidate to addressing challenges in pulp regeneration. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis reveal the successful synthesis of PSC-Heparin. Scanning electron microscopy and X-ray diffraction show the hydroxyapatite formation can be observed on the surface of PSC-Heparin after soaking in simulated body fluid for 12 h. PSC-Heparin is capable of harvesting various endogenous GFs and sustainably releasing them over an extended duration by the enzyme-linked immunosorbent assay. Cytological experiments show that developed PSC-Heparin can facilitate the adhesion, migration, proliferation, and odontogenic differentiation of stem cells from apical papillae. Notably, the histological analysis of subcutaneous implantation in nude mice demonstrates PSC-Heparin is capable of promoting the odontoblast-like layers and pulp-dentin complex formation without the addition of exogenous GFs, which is vital for clinical applications. This work highlights an effective strategy of harvesting endogenous GFs and avoiding the involvement of exogenous GFs to achieve pulp-dentin complex regeneration, which may open a new horizon for regenerative endodontic therapy.

A microfluidic concentration gradient colorimetric system for rapid detection of nitrite in surface water

A microfluidic concentration gradient colorimetric detection system consisting of a microfluidic concentration gradient colorimetric detection chip, a self-built colorimetric signal acquisition box and a self-written smartphone APP was constructed for the rapid, in-field and visual quantitative detection of nitrite. Specifically, nitrite with initial concentration of C0 can be automatically diluted into 8 concentration gradients characterized by arithmetic series, and the concentrations are 0, 0.20 C0, 0.33 C0, 0.46 C0, 0.59 C0, 0.72 C0, 0.86 C0 and C0. The colorimetric signal acquisition box avoided the interference of light spots on data acquisition. Under the optimal experimental conditions, the quantitative detection of nitrite was achieved by the proposed two-step colorimetric method based on the inhibition of AuNPs signal amplification, and the limit of detection (LOD) was 0.14 mg/L. The microfluidic concentration gradient colorimetric detection system was able to detect nitrite as low as 0.43 mg/L and showed a good specificity. The practical application was investigated by analyzing 10 actual samples of river and lake water, pure water and tap water. The recoveries of the microfluidic concentration gradient colorimetric detection system ranged from 94.92% to 105.60%, which indicates that the method had a good application prospect in the detection of practical samples.

Search for immunomodulatory compounds with antiproliferative activity against melanoma

BACKGROUND

Melanoma is a highly aggressive neoplasm with a high degree of malignancy and rapid acquisition of resistance by cancer cells.

METHODS

Biological studies of a series of isoxazole compounds with immunomodulatory properties were preceded by in silico analysis. The assay evaluated the viability of NHDF and A375 cell cultures after the administration of isoxazole compounds after a 24-hour incubation period in the MTT test. Analyzes of ROS and NO scavenging, P-glycoprotein activity, and properties were performed. The levels of Caspase 3 and Caspase 9 were measured using ELISA to assess which pathways induced apoptosis by the tested compounds. On the chip, the synergistic effect of doxorubicin and the most active compound from the MM9 series on cells of the A375 melanoma line was determined.

RESULTS

All tested N'-substituted derivatives of 5-amino-N,3-dimethyl-1,2-oxazole-4-carbohydrazide with immunomodulatory activity show multidirectional antitumor activity on A375 melanoma lines with an affinity for P-glycoprotein, induction of free radical formation and generation of DNA damage leading to the death of cancer cells, as well as formation of complexes with DNA Topoisomerase II. Most of the tested compounds show pro-apoptotic activity. The most active compound in the series induces apoptosis in three distinct pathways and acts synergistically with doxorubicin.

CONCLUSIONS

The most active compound with immunomodulatory properties showed multidirectional antitumor activity against cells of the A375 melanoma line and also had a synergistic pro-apoptotic effect with doxorubicin, which may result in a reduction of this cytostatic dose with increased effectiveness.

Analysis of Static Molecular Gradients in a High-Throughput Drug Screening Microfluidic Assay

In this study, we thoroughly analyzed molecular gradient generation, its stability over time, and linearity in our high-throughput drug screening microfluidic assay (HTS). These parameters greatly affect the precision and accuracy of the device's analytical protocol. As part of the research, we developed a mathematical model of dependence of the concentration profile on the initial concentrations of active substances in reservoirs and the number of tilts, as well as the dependence of the active substance concentration profiles in the culture chambers on the concentration profile of the reference dye in the indicator chamber. The mean concentration prediction error of the proposed equations ranged from 1.4% to 2.4% for the optimized parameters of the procedure and did not increase with the incubation time. The concentration profile linearity index, Pearson's correlation coefficient reached -0.997 for 25 device tilts. The observed time stability of the profiles was very good. The mean difference between the concentration profile after 5 days of incubation and the baseline profile was only 7.0%. The newly created mathematical relationships became part of the new HTS biochip operating protocols, which are detailed in the article.