The development of ionizable lipid (IL) was necessary to enable the effective formulation of small interfering RNA (siRNA) to inhibit P2X7 receptors (P2X7R), a key player in tumor proliferation, apoptosis, and metastasis. In this way, the synthesis and utility of IL for enhancing cellular uptake of lipid nanoparticles (LNP) improve the proper delivery of siRNA-LNPs for knockdown overexpression of P2X7R. Therefore, to evaluate the impact of P2X7 knockdown on breast cancer (BC) migration and apoptosis, a branched and synthesized ionizable lipid (SIL) was performed for efficient transfection of LNP with siRNA for targeting P2X7 receptors (siP2X7) in mouse 4T-1 cells. Following synthesis and structural analysis of SIL, excellent characterization of the LNP was achieved (Z-average 126.8 nm, zeta-potential - 12.33, PDI 0.16, and encapsulation efficiency 85.35%). Afterward, the stability of the LNP was evaluated through an analysis of the leftover composition, and toxic concentration values for SIL and siP2X7 were determined. Furthermore, siP2X7-LNP cellular uptake in the formulation was assessed via confocal microscopy. Following determining the optimal dose (45 pmol), wound healing analysis was assessed using scratch assay microscopy, and apoptosis was evaluated using flow cytometry. The use of the innovative branched SIL in the formulation of siP2X7-LNP resulted in significant inhibition of migration and induction of apoptosis in 4T-1 cells due to improved cellular uptake. Subsequently, the innovative SIL represents a critical role in efficiently delivering siRNA against murine triple-negative breast cancer cells (TNBC) using LNP formulation, resulting in significant efficacy.