Growth characteristics of human bone marrow mesenchymal stromal cells at cultivation on synthetic polyelectrolyte nanofilms in vitro

Novel Kraft Softwood Lignin-Derived Carbon Quantum Dots: Synthesis, Characterization, and In Vitro Cytocompatibility

Carbon quantum dots (CQDs) have been investigated for biomedical applications in medical imaging due to their fluorescent properties, overall long-term stability, and excellent cytocompatibility and biocompatibility. Lignin is an organic polymer in the tissues of woody plants. It is also considered a byproduct of the wood and pulp industries. Hence, it presents as a renewable source of carbon nanoparticles. In this study, we report the synthesis and material and biological characterization of two colloidal suspensions of CQDs in water derived from lignin-based carbon. One was the native form of CQDs derived from lignin carbon, and the second was doped with nitrogen to evaluate material differences. Material characterization was carried out using various commonly used techniques, including Fourier transform infrared spectroscopy (FTIR), emission and absorbance spectra, zeta potential, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Thin films of CQDs were formed on glass and silicon substrates to assess the in vitro cytocompatibility with human mesenchymal stem cells (hMSCs). Observations suggest that the two forms of CQDs promote cell attachment within 24 h and sustain it for at least 7 days. The overall structure and shape of cells suggest a lack of any adverse or toxic effects of CQDs. The data lay down the novel foundation to support the use of lignin-derived CQDs in tissue engineering applications.

Poly(allylguanidine)-Coated Surfaces Regulate TGF-β in Glioblastoma Cells to Induce Apoptosis via NF-κB Pathway Activation

Polycationic biomaterials are currently widely applied in neuronal cell cultures to promote cell adhesion and viability. However, polycations generally have cytotoxic properties that limit their application in the field of biomaterials. In this study, we examined the use of a novel polycation poly(allylguanidine) (PAG), which contains a guanidine group in the side chain and a structure similar to poly(allylamine hydrochloride) (PAH), an example of another commonly used polycation. Our findings showed that exposure to PAG induced apoptosis in glioblastoma (GBM) cells, while exposure to PAH induced necrosis. Compared to control groups, the PAG coating significantly limited the proliferation of GBM8901 in vitro and in vivo. Furthermore, GBM8901 cells exposed to the PAG coating exhibited increased levels of phospho-p65 and phosphor-IκB, implying that GBM8901 cells underwent apoptotic cell death via the NF-κB pathway by the regulation of TGF-β. This result was further confirmed to be consistent with the experimental results from western blot protein analysis and apoptosis/necrosis assays. These findings indicate that the polycation PAG has the potential to not only suppress the proliferation of GBM8901 cancer cells but also improve the neural viability and promote the differentiation of neural stem/precursor cells into mature neurons. In conclusion, biomaterials such as PAG act as extremely potent options for applications in the treatment of pathological conditions such as brain cancer.