In recent years, in addition to the positive effects of probiotics and prebiotics on health, increasing research has shown that postbiotics also have significant potential in the health field. Postbiotics are bioactive components produced by probiotic bacteria during fermentation and may exhibit antimicrobial activity. This study investigated the antimicrobial effects of liposomal postbiotics formulated in gel. Various postbiotic-containing liposomal systems have been developed and optimized to prepare formulations. Optimized liposomes and liposomal postbiotic-containing gel forms were examined in terms of particle size, polydispersity index, zeta potential, structural properties, encapsulation efficiency, permeability, release profiles, and stability. Finally, the antimicrobial activities of the postbiotics and the optimum gel formulation LG1 were evaluated on Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Enterococcus hirae, and Candida albicans strains using disk diffusion and microdilution methods. The optimum liposome formulation L1 was determined to have a particle size of 185.32 ± 0.80 nm, a polydispersity index of 0.206 ± 0.012, a zeta potential of 35.0 ± 0.5 mV, and an encapsulation efficiency of 17.52%. Its permeability was determined as 51.52% at the end of 6 h. In vitro release studies showed that the drug release profile was in accordance with first-order kinetics and suitable for controlled release. The findings show that formulated postbiotics have similar antimicrobial activity to free postbiotics. These results suggest that liposomal gel formulations support the antimicrobial effects of postbiotics while providing advantages of use. In conclusion, the findings contribute to a better understanding of the antimicrobial potential of postbiotics and lipogelosomal postbiotics and optimize their use in pharmaceutical applications.

Background: Gum Arabic (GA) is a natural polysaccharide widely recognized for its antioxidant and anti-inflammatory properties; however, its functional behavior as a biopolymeric gel and the mechanisms underlying its selective effects on cancer-related redox microenvironments remain insufficiently characterized. It is imperative to note that the interaction between its physicochemical properties and its biological activity in colorectal cancer remains to be fully clarified. Methods: This study aimed to evaluate the antineoplastic potential of GA in human colorectal cancer (CRC) cell lines (HT-29 and HCT-116) compared to normal fibroblasts (MRC-5) using the MTS assay. Oxidative stress-related molecular responses were assessed by quantitative PCR analysis of GPX4, GSTA2, CAT, NFKB, and SOD1 expression. In parallel, extracellular concentrations of key metal ions (Fe²⁺, Zn²⁺, Mn²⁺, Mg²⁺, Cu²⁺, and Al³⁺) were quantified following GA exposure. To establish its functional gel characteristics, rheological measurements were performed to assess viscosity and shear-dependent behavior, and USP-compliant in vitro kinetic studies were conducted to evaluate time-dependent release properties. Results: GA induced dose-dependent cytotoxicity in HT-29 and HCT-116 colorectal cancer cells, while MRC-5 fibroblasts exhibited comparatively higher viability across the tested concentration range, indicating reduced sensitivity in normal cells. Rheological analysis revealed concentration- and ion-dependent viscoelastic behavior, identifying a 10% (w/w) GA formulation as optimal due to its balanced low-shear viscosity and controlled shear-thinning properties. Kinetic studies demonstrated a defined, diffusion-governed release profile under physiologically relevant conditions. At the molecular level, significant upregulation of GPX4 and GSTA2 was observed in both cancer cell lines, whereas NFKB expression increased selectively in HT-29 cells, with no notable changes in CAT or SOD1 expression. Additionally, GA treatment resulted in marked increases in Fe²⁺, Zn²⁺, and Mn²⁺ levels, indicating modulation of the redox–ionic microenvironment. Conclusions: These findings demonstrate that GA functions as a natural, ion-responsive biopolymeric system with defined rheological and kinetic properties, capable of selectively targeting colorectal cancer cells through coordinated genetic and ionic regulation of oxidative stress. Collectively, the results position GA as a promising functional gel-based platform for future redox-modulated therapeutic strategies in colorectal cancer.

Postbiotics are bioactive microbial metabolites recognized for their potential to support skin health and balance the microbiota. In this study, nonwoven fabrics and adult diaper prototypes, with and without postbiotic incorporation, were evaluated for their effects on skin microbiota, epidermal integrity, and cytotoxicity. In vitro assays using reconstructed human epidermis and keratinocyte cell lines demonstrated that postbiotic-containing samples maintained high tissue and cell viability. Microbiota diversity analyses confirmed that postbiotic formulations maintained a favorable ratio of Staphylococcus epidermidis to Staphylococcus aureus. Collectively, these findings indicate that ATA-coded postbiotic-embedded nonwoven and adult diaper prototypes are skin microbiota-friendly, safe for epidermal contact, and stable in their bioactive compound content. These results underscore the potential of postbiotics as functional agents in personal hygiene products to promote skin health.

Background/Objectives: Atopic dermatitis (AD) is associated with gut dysbiosis linked to early-life antibiotic use and Staphylococcus aureus colonization. Gum Arabic (GA), a prebiotic, may modulate this dysbiosis and influence AD-related microbial balance. This study evaluated whether GA could support AD-associated probiotics-Lactobacillus casei, Bifidobacterium bifidum, and Bifidobacterium infantis-under amoxicillin- or azithromycin-containing conditions, examined the response of S. aureus under the same screening conditions, and developed GA-phospholipid-based semisolid carriers for topical application. Methods: Probiotic strains were cultured with 1–5% GA in the presence and absence of antibiotics, and viable cell counts were assessed. Sixteen topical formulations containing propylene glycol or isopropyl myristate in a hydrogenated phosphatidylcholine base were prepared and screened for rheological properties and galactose release using in vitro release testing (IVRT) and HPLC-UV. Results: GA at 1–2% concentrations promoted probiotic growth in antibiotic-free conditions. GA preserved B. infantis viability under azithromycin exposure in this in vitro screening model. For S. aureus, numerical CFU differences were observed between antibiotic-only and GA-containing conditions; however, the present screening design was not intended to determine antibiotic interaction outcomes. Formulations F14 (2% GA + 7% IPM) and F15 (3% GA + 7% IPM) exhibited optimal spreadability. IVRT showed that 6 h cumulative galactose release varied by formulation (F6 > F10 > F14 > F15). Conclusions: GA demonstrated dose-dependent prebiotic activity and preserved B. infantis viability under azithromycin exposure in this in vitro screening model. For S. aureus, the observed CFU differences between antibiotic-only and GA-containing conditions should be considered exploratory only and do not allow for conclusions regarding interference with antibiotic efficacy. Optimized GA-HPC systems with suitable rheological and release characteristics represent promising candidates for further preclinical investigation.