The present study highlighted that the synthesis of β-Glucan nanoparticles (β-GluNPs) developed as a facile method to prevent cancer and infectious diseases, which is highly effective and inexpensive in the biological field. This research study has demonstrated the use of marine algae (Gracilaria corticate) to extract water-soluble β-Glucan and synthesis of β-GluNPs by dissolving the extracted β-Glucan in NaOH under optimal conditions. The molecular structure of the extracted and stabilized β-GluNPs was analysed using NMR. Further, the Physico-chemical parameters of β-GluNPs were analysed by the high throughput instruments like UV spectroscopy, FTIR, DLS, ZETA Potential, SEM, HRTEM, and XRD analysis. The synthesis of β-GluNPs confirmed by IR spectroscopy. The HR-TEM results demonstrated that the formation of polydispersed nanoparticles with a mean size of 20 ± 5 nm. The hydrostatic zeta potential was − 22.7mV, which indicated their colloidal stability. The XRD pattern revealed the crystalline nature of the nanoparticles. Besides, β-GluNPs performed better antibacterial activity against the tested pathogens. The apoptosis and DNA fragmentation observed to be IC50 42.5 µg/ml of the β-GluNPs. The DNA fragmentation assay indicated the selective inhibition of the MCF-7 cell line by DNA damage. Hence, β-GluNPs used as a promising alternative drug against human breast cancer.