The principal focus of this work is the in-depth analysis of the biological efficiency of inorganic calcium-filled bacterial cellulose (BC) based hydrogel scaffolds for their future use in bone tissue engineering/bioengineering. Inorganic calcium was filled in the form of calcium phosphate (β-tri calcium phosphate (β-TCP) and hydroxyapatite (HA)) and calcium carbonate (CaCO₃). The additional calcium, CaCO₃ was incorporated following in vitro bio-mineralization. Cell viability study was performed with the extracts of BC based hydrogel scaffolds: BC-PVP, BC-CMC; BC-PVP-β-TCP/HA, BC-CMC-β-TCP/HA and BC-PVP-β-TCP/HA-CaCO₃, BC-CMC-β-TCP/HA-CaCO₃; respectively. The biocompatibility study was performed with two different cell lines, i.e., human fibroblasts, Lep-3 and mouse bone explant cells. Each hydrogel scaffold has facilitated notable growth and proliferation in presence of these two cell types. Nevertheless, the percentage of DNA strand breaks was higher when cells were treated with BC-CMC based scaffolds i.e., BC-CMC-β-TCP/HA and BC-CMC-β-TCP/HA-CaCO₃. On the other hand, the apoptosis of human fibroblasts, Lep-3 was insignificant in BC-PVP-β-TCP/HA. The scanning electron microscopy confirmed the efficient adhesion and growth of Lep-3 cells throughout the surface of BC-PVP and BC-PVP-β-TCP/HA. Hence, among all inorganic calcium filled hydrogel scaffolds, ‘BC-PVP-β-TCP/HA’ was recommended as an efficient tissue engineering scaffold which could facilitate the musculoskeletal (i.e., bone tissue) engineering/bioengineering.

In the present study, novel conjugated lignin/chitosan nanoparticles (LCNPs) were synthesized by a first-time simple green methodology using interfacial co-assembly between both biopolymers. The physicochemical (ζ-potential, size, concentration of surface acidic/basic groups), structural (surface functional groups), and morphological characteristics of the blank and quercetin-encapsulated (Q-LCNPs) nanoparticles were analyzed by the Boehm method, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The experimentally determined encapsulation capacity was satisfactory—95.75%. The in vitro quercetin release efficiency in acidic solution that simulated the gastric microenvironment was 21.9%, followed by 68.5% and 99.8% cumulative release efficiency in simulated intestinal media at pH 7.4 and 6.8, respectively. The satisfactory applicability of the Weibull and sigmoidal mathematical models towards the experimental in vitro release data was indicative of the remarkable roles of diffusion and relaxation mechanisms.

Background/Objectives: The aim of the present study was to conduct a systematic in vitro assessment of the biofunctionalities of newly synthesized lignin (LNPs) and lignin–chitosan nanoparticles (LCNPs) via a comparative in vitro estimation of their cytotoxicity, cytocompatability potential, radical-scavenging activity, and antimicrobial performance, thereby establishing a benchmark for their sustainable design and biomedical applications. Methods: LNPs and LCNPs were synthesized via “green” self-assembly and co-assembly methods. Results: In vitro cytotoxicity studies on L929 fibroblasts and HaCaT keratinocytes demonstrated higher long-term viability for LCNPs (half-maximal inhibitory concentration IC₅₀ = 3.05 mg/mL at 72 h) compared with LNPs (IC₅₀ = 1.37 mg/mL), while both formulations maintained >76% viability at a concentration of 0.5 mg/mL. Electron Paramagnetic Resonance (EPR) and spectrophotometric antioxidant assays displayed strong radical scavenging activity, with LNPs excelling in ^●OH, NO, and ABTS scavenging and LCNPs exhibiting enhanced lipid peroxidation and superoxide inhibition potential. Antimicrobial testing revealed minimal inhibitory concentration (MIC) reductions of the nanoparticles up to 8–13-fold compared to lignin solutions, with LCNPs showing higher activity against Gram-positive and Gram-negative microbial strains. Conclusions: These results highlight LCNPs as biocompatible, antioxidant, and antimicrobial nanoplatforms with potential for regenerative medicine, oxidative stress mitigation, and infection control.

Plant extracts remain an important source of antiviral agents, while nanocarrier-based delivery systems have emerged as a promising strategy for improving their therapeutic safety and efficacy. Building on previous findings indicating that nanoliposomal encapsulation improved the anti-coronavirus activity of Aesculus hippocastanum seed extract against human coronavirus strain OC43 (HCoV-OC43), the present study evaluated whether encapsulation reduces the genotoxic effects of the extract and explored a potential molecular basis for the previously observed antiviral activity. Genotoxicity assessment using the alkaline comet assay in MRC-5 human lung fibroblasts demonstrated that at 1 mg/mL, liposomal encapsulation was associated with an approximately 86.0% reduction in %Tail DNA, from 21.301 ± 0.368% for the free extract to 2.984 ± 1.523% for the liposome-encapsulated extract. In parallel, chemical profiling by high-performance liquid chromatography coupled with high-resolution tandem mass spectrometry (HPLC–HRMS/MS) enabled the identification and tentative annotation of 46 metabolites, including triterpenoid saponins, flavonoids, indole-3-acetic acid glycosides, and organic acids. Based on this phytochemical profile, representative constituents were subjected to molecular docking against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nonstructural proteins Nsp5 and Nsp12 to investigate their potential contribution to the previously demonstrated antiviral activity of the extract. Among the evaluated compounds, hesperidin exhibited the most favorable predicted binding affinity toward both targets, while quercetin also showed favorable interactions, suggesting that flavonoid constituents may contribute to the antiviral activity of the extract. These findings indicate that liposomal encapsulation improves the biological safety profile of A. hippocastanum seed extract, while phytochemical characterization and molecular docking provide preliminary insights into the constituents that may contribute to its previously demonstrated anti-coronavirus activity.