Background Silver nanoparticles (AgNPs) are gaining traction in many industries and sectors due to their exceptional physical and chemical characteristics. The purpose of this research was to determine the efficiency of marine bacterial-mediated AgNPs functionalized with matcha (AgNPs-Matcha) in different biological activities. Methodology AgNPs were biosynthesized extracellularly by the marine Klebsiella sp. RR1 and loaded with matcha extract (AgNPs-Matcha). Both AgNPs and AgNPs-Matcha were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), BET surface area, and Fourier transform infrared spectroscopy (FT-IR). AgNPs and AgNPs-Matcha were evaluated for biomedical applications, including antibacterial, antioxidant, anti-inflammatory, and anti-breast cancer effects via apoptotic gene regulation. Results The optimal growth of Klebsiella sp. RR1 was highly dependent on the NaCl concentration in the medium (3%), with an optimal pH of 8 at 30 °C. The optimal extracellular biosynthesis of AgNPs was achieved using 0.5 mM AgNO₃ at pH 10 and 60 °C for 24 h, as confirmed by UV-Vis spectroscopy (λmax = 461). AgNPs were loaded with matcha extract and evaluated in different biological activities. SEM confirmed the synthesis of spherical AgNPs (22–26 nm) and AgNPs-Matcha (23.9–32.9 nm), and TEM showed spherical AgNPs (12.37–24.64 nm) and AgNPs-Matcha (12.9–28.9 nm). Matcha loading improved particle dispersion, broadened the size distribution slightly, and demonstrated successful surface functionalization. EDX spectra confirmed the metallic Ag composition of both samples. The AgNPs-Matcha spectrum also showed peaks from the matcha extract, verifying successful surface functionalization. XRD confirmed the FCC crystalline structure of biogenic AgNPs, with sharp diffraction peaks at 38.53°, 44.4°, 63.3°, and 77.9°, and the average crystallite size was estimated at 14 nm using the Scherrer equation. Nitrogen adsorption–desorption analysis revealed that the incorporation of matcha significantly altered the textural properties of AgNPs. The BET surface area of AgNPs (234.48–254.52 m²/g) decreased by approximately half in the AgNPs–Matcha composite (118.65–127.43 m²/g). Concurrently, the total pore volume reduced from 0.54 to 0.326 cm³/g, while the average pore diameter increased from 8.5 to 10.9 nm. AgNPs displayed broad-spectrum bactericidal activity. A synergistic effect with matcha was observed, significantly lowering the MIC and MBC against Escherichia coli and Bacillus subtilis, highlighting the enhanced potency of the AgNPs-Matcha formulation. Loading with matcha halved both the MIC and MBC against E. coli and B. subtilis to 250 and 500 µg/ml, respectively. While less potent than standard antibiotics, the AgNPs-Matcha formulation shows promise as a bactericidal agent. AgNPs demonstrated antioxidant activity (IC50 = 31.09 µg/ml); however, AgNPs-Matcha showed a greater antioxidant effect (IC50 = 28.80 µg/ml). The biosynthesized AgNPs exhibited a dose-dependent anti-inflammatory activity against cyclooxygenase (COX) enzymes, but with only moderate potency. A profound enhancement was achieved upon functionalization with matcha extract. AgNPs-Matcha showed inhibition of COX-1 and COX-2, with markedly lower IC₅₀ values (13.18 and 6.42 µg/ml, respectively) than plain AgNPs (IC50=33.27 and 26.84 µg/ml for COX-1 and COX-2, respectively). In addition, the AgNPs-Matcha demonstrated superior, dose-dependent cytotoxicity against MCF-7 (breast cancer cells), with an IC50 value nearly 5-fold lower than AgNPs alone (16.92 vs. 80.60 µg/ml), indicating significantly enhanced potency. By repressing the anti-apoptotic BCL-2 gene and increasing the pro-apoptotic BAX gene, the two therapies mechanistically produced cell death. However, AgNPs-Matcha was far more effective, elevating the pivotal BAX/BCL-2 ratio to 8.46, more than double the ratio induced by AgNPs (3.97). Conclusion From these results, our study proved a significant synergistic effect achieved by loading matcha onto the biogenic AgNPs, positioning this novel composite as a promising candidate for further therapeutic investigation. Functionalization with matcha significantly enhanced the bioactivity of AgNPs, yielding a composite with potent antibacterial activity against pathogens such as E. coli and B. subtilis, strong antioxidant capacity, and markedly improved anti‑inflammatory activity. Most notably, AgNPs‑Matcha exhibited 5‑fold greater cytotoxicity against MCF‑7 cells, promoting apoptosis through a heightened BAX/BCL‑2 ratio. These results position the composite as a promising multi‑target therapeutic agent from sustainable sources.

Marine Klebsiella sp. RR1-mediated AgNPs functionalized with matcha: synthesis, characterization, and evaluation of antibacterial, antioxidant, anti-inflammatory, and gene regulation of breast cancer potentials

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2026年3月14日

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Reem M. Farsi,
Rasha A. Metwally

摘要

Background

Silver nanoparticles (AgNPs) are gaining traction in many industries and sectors due to their exceptional physical and chemical characteristics. The purpose of this research was to determine the efficiency of marine bacterial-mediated AgNPs functionalized with matcha (AgNPs-Matcha) in different biological activities.

Methodology

AgNPs were biosynthesized extracellularly by the marine Klebsiella sp. RR1 and loaded with matcha extract (AgNPs-Matcha). Both AgNPs and AgNPs-Matcha were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), BET surface area, and Fourier transform infrared spectroscopy (FT-IR). AgNPs and AgNPs-Matcha were evaluated for biomedical applications, including antibacterial, antioxidant, anti-inflammatory, and anti-breast cancer effects via apoptotic gene regulation.

Results

The optimal growth of Klebsiella sp. RR1 was highly dependent on the NaCl concentration in the medium (3%), with an optimal pH of 8 at 30 °C. The optimal extracellular biosynthesis of AgNPs was achieved using 0.5 mM AgNO₃ at pH 10 and 60 °C for 24 h, as confirmed by UV-Vis spectroscopy (λmax = 461). AgNPs were loaded with matcha extract and evaluated in different biological activities. SEM confirmed the synthesis of spherical AgNPs (22–26 nm) and AgNPs-Matcha (23.9–32.9 nm), and TEM showed spherical AgNPs (12.37–24.64 nm) and AgNPs-Matcha (12.9–28.9 nm). Matcha loading improved particle dispersion, broadened the size distribution slightly, and demonstrated successful surface functionalization. EDX spectra confirmed the metallic Ag composition of both samples. The AgNPs-Matcha spectrum also showed peaks from the matcha extract, verifying successful surface functionalization. XRD confirmed the FCC crystalline structure of biogenic AgNPs, with sharp diffraction peaks at 38.53°, 44.4°, 63.3°, and 77.9°, and the average crystallite size was estimated at 14 nm using the Scherrer equation. Nitrogen adsorption–desorption analysis revealed that the incorporation of matcha significantly altered the textural properties of AgNPs. The BET surface area of AgNPs (234.48–254.52 m²/g) decreased by approximately half in the AgNPs–Matcha composite (118.65–127.43 m²/g). Concurrently, the total pore volume reduced from 0.54 to 0.326 cm³/g, while the average pore diameter increased from 8.5 to 10.9 nm. AgNPs displayed broad-spectrum bactericidal activity. A synergistic effect with matcha was observed, significantly lowering the MIC and MBC against Escherichia coli and Bacillus subtilis, highlighting the enhanced potency of the AgNPs-Matcha formulation. Loading with matcha halved both the MIC and MBC against E. coli and B. subtilis to 250 and 500 µg/ml, respectively. While less potent than standard antibiotics, the AgNPs-Matcha formulation shows promise as a bactericidal agent. AgNPs demonstrated antioxidant activity (IC₅₀ = 31.09 µg/ml); however, AgNPs-Matcha showed a greater antioxidant effect (IC₅₀ = 28.80 µg/ml). The biosynthesized AgNPs exhibited a dose-dependent anti-inflammatory activity against cyclooxygenase (COX) enzymes, but with only moderate potency. A profound enhancement was achieved upon functionalization with matcha extract. AgNPs-Matcha showed inhibition of COX-1 and COX-2, with markedly lower IC₅₀ values (13.18 and 6.42 µg/ml, respectively) than plain AgNPs (IC₅₀=33.27 and 26.84 µg/ml for COX-1 and COX-2, respectively). In addition, the AgNPs-Matcha demonstrated superior, dose-dependent cytotoxicity against MCF-7 (breast cancer cells), with an IC₅₀ value nearly 5-fold lower than AgNPs alone (16.92 vs. 80.60 µg/ml), indicating significantly enhanced potency. By repressing the anti-apoptotic BCL-2 gene and increasing the pro-apoptotic BAX gene, the two therapies mechanistically produced cell death. However, AgNPs-Matcha was far more effective, elevating the pivotal BAX/BCL-2 ratio to 8.46, more than double the ratio induced by AgNPs (3.97).

Conclusion

From these results, our study proved a significant synergistic effect achieved by loading matcha onto the biogenic AgNPs, positioning this novel composite as a promising candidate for further therapeutic investigation. Functionalization with matcha significantly enhanced the bioactivity of AgNPs, yielding a composite with potent antibacterial activity against pathogens such as E. coli and B. subtilis, strong antioxidant capacity, and markedly improved anti‑inflammatory activity. Most notably, AgNPs‑Matcha exhibited 5‑fold greater cytotoxicity against MCF‑7 cells, promoting apoptosis through a heightened BAX/BCL‑2 ratio. These results position the composite as a promising multi‑target therapeutic agent from sustainable sources.