Algal-Derived Synthesis of Silver Nanoparticles Using the Unicellular ulvophyte sp. MBIC10591: Optimisation, Characterisation, and Biological Activities

Abstract

Algal-mediated synthesis of nanoparticles (NPs) is an eco-friendly alternative for producing NPs with potent physicochemical and biological properties. Microalgae represent an ideal bio-nanofactory because they contain several biomolecules acting as passivation and stabilising agents during the biogenesis of NPs. Herein, a novel microalgae sp. was isolated, purified, and identified using light and electron microscopy and 18s rRNA sequencing. The chemical components of their watery extract were assessed using GC-MS. Their dried biomass was used to synthesise silver (Ag) NPs with different optimisation parameters. Ag-NPs were physiochemically characterised, and their anticancer and antibacterial effects were examined. The data showed that the isolated strain was 99% similar to the unicellular ulvophyte sp. MBIC10591; it was ellipsoidal to spherical and had a large cup-shaped spongiomorph chloroplast. The optimum parameters for synthesising Ag-NPs by unicellular ulvophyte sp. MBIC10591 (Uv@Ag-NPs) were as follows: mixture of 1 mM of AgNO3 with an equal volume of algal extract, 100 °C for 1 h, and pH of 7 under illumination for 24 h. TEM, HRTEM, and SEM revealed that Uv@Ag-NPs are cubic to spherical, with an average nanosize of 12.1 ± 1.2 nm. EDx and mapping analysis showed that the sample had 79% of Ag, while FTIR revealed the existence of several functional groups on the NP surface derivatives from the algal extract. The Uv@Ag-NPs had a hydrodynamic diameter of 178.1 nm and a potential charge of −26.7 mV and showed marked antiproliferative activity against PC3, MDA-MB-231, T47D, and MCF-7, with IC50 values of 27.4, 20.3, 23.8, and 40 µg/mL, respectively, and moderate toxicity against HFs (IC50 of 13.3 µg/mL). Uv@Ag-NPs also showed marked biocidal activity against Gram-negative bacteria. Escherichia coli was the most sensitive bacteria to the NPs with an inhibition zone of 18.9 ± 0.03 mm. The current study reports, for the first time, the morphological appearance of the novel unicellular ulvophyte sp., MBIC10591, and its chemical composition and potential to synthesise Uv@Ag-NPs with smaller sizes and high stability to act as anti-tumour and microbial agents.

Characterization of Silver Nanoparticle Systems from Microalgae Acclimated to Different CO2 Atmospheres

“…In agreement with other reports (see Table ), AgNP characteristics depended on microalgae species, the biological component used, and the pH of the solution. , These effects result in a wide range of nanoparticle sizes reported for phylogenetically close species of green algae (5–178 nm) ,,− ,− and cyanobacteria (5–242 nm). ,− …”

Planophila laetevirens-Mediated Synthesis of Silver Nanoparticles: Optimization, Characterization, and Anticancer and Antibacterial Potentials

“…The MTT assay was performed according to the method described by Mosmann and the plates were read using a plate reader at 570 nm. Cell viability (%) was estimated using the following equation: , false( Abs ( treated ) / ( Abs false( control false) ) × 100 The IC 50 (half-maximal growth inhibitory concentration) was calculated from a sigmoidal curve.…”

“…The samples were prepared according to the method described in our previous article. 16 Anticancer Activity of Ag-NPs. Colon cancer cell lines (Sw620 and HT-29), breast cancer cell lines (MDA-MB231 and MCF-7), and the normal human fibroblast cell line (HFs) were obtained from American Type Culture Collection (ATCC, Manassas, VA, USA) and cultured in RPMI (HT-29) and DMEM supplemented by 10% FBS, and 50 U/mL penicillin and streptomycin and kept at 37 °C in a 5% CO 2 incubator until 75% confluency.…”

“…Notably, 5-FU and Ch@Ag-NPs were assessed only against Sw620 and HT-29 cells, while MCF-7, MDA-MB-231, and HFs were assessed and published in our previous articles. 16,26 The cells (5 × 10 4 cells/mL) were cultured in 96-well plates and kept in a 5% CO 2 incubator for 24 h at 37 °C until they reached 75% confluency and the cells were treated with serial dilutions of S-P@Ag-NPs and B-P@Ag-NPs at 200.0, 100.0, 50.0, 25.0, 12.5, 6.25, 3.13, 1.56, and 0.78 μg/mL, and 1000, 500, 250, 125, 62.5, 31.25, 15.62, 7.81, and 3.90 μg/mL of Ch@Ag-NPs and 5-FU. Then, the plates were incubated for 24 h in a 5% CO 2 incubator at 37 °C.…”

“…Researchers have recently reported computational and traditional optimization processes for NPs synthesis . Changing the concentrations of precursors, temperature, pH, illumination conditions, and other abiotic and biotic factors mitigates the stability, shape, and size of NPs. , Additionally, researchers have found that synthesizing NPs using specific extracted biomolecules, such as pigments, enzymes, and proteins, regulates their shape and size . Microalgae and cyanobacteria have many distinguishing characteristics that make them promising biofactories for NPs synthesis compared to other green synthesis routes.…”