Liposome Synthesis Protocol : Synthesis of anionic and cationic unilamellar liposome nanoparticles using a thin film dispersed hydration and extrusion method. v1
Authors: Carroll Joanna 
Published: January 2023

Nanoparticles are the future of targeted and sustained drug delivery, yielding significant opportunities in addressing and treat challenging diseases such as cancer (Grenader et al., 2012; Luminari et al., 2010; Shoji et al., 2014). These nano vesicles can be developed into intelligent systems which can encapsulate medicinal and imaging agents, while still possessing stealth properties. Manipulating the size, surface properties, and material composition of these novel systems can help deliver drugs to specific tissues and provide controlled release therapy. Among them, lipid nanoparticles, particularly liposomes, have been identified as promising and adaptable drug vesicles. When compared to standard drug delivery systems, they have superior qualities such as site-targeting, prolonged or controlled release, drug protection from degradation and clearance, superior therapeutic efficacy, and lower toxic side effects. Liposomes are phospholipid vesicles that form approximately spherical bilayer shapes. These spherical vesicles can contain unilamellar or multilamellar internal concentric lipid bilayers trapping aqueous space. Due to this structure, liposomal vesicles allow for a wide variety of drugs with lipophilic and hydrophilic properties to be encapsulated simultaneously with hydrophobic/lipophilic molecules being inserted into the bilayer membrane and hydrophilic molecules being entrapped in the aqueous compartments. Beginning with Gabizon et al., 1982 and Tardi et al., 1985, liposome researchers have developed a wide range of liposomal drug carriers, by primarily employing small-scale laboratory techniques. The size of liposomes has a significant role in the effective delivery of anticancer drugs to the tumour site. Liposome size has been demonstrated to affect its time in blood circulation, tumour accumulation, tumour retention and the drug release. According to data so far, a liposome diameter of below 200 nm is the ideal size to achieve efficient drug delivery especially when targeting the brain and crossing the blood brain barrier (Gao et al., 2013; Kulkarni & Feng, 2013). This protocol aims to outline the steps involved in the synthesis of cationic and anionic liposomes with an approximate uniform size of 90 nm for targeted drug delivery in tumour cells. This method employed the use of thin-film dispersed hydration one of the most popular methods for preparing liposomes. References Gabizon, A. et al. (1982) “Liposomes as in Vivo Carriers of Adriamycin: Reduced Cardiac Uptake and Preserved Antitumor Activity in Mice,” American Association for Cancer Research, 42(11), pp. 4734–4739. PMID: 7127308 Gao, W. et al. (2013) “Liposome-like nanostructures for drug delivery,” Journal of Materials Chemistry B, 1(48), p. 6569. DOI:10.1039/C3TB21238F Grenader, T. et al. (2012) “Pegylated liposomal doxorubicin/carboplatin combination in ovarian cancer, progressing on single-agent pegylated liposomal doxorubicin,” World Journal of Clinical Oncology, 3(10), p. 137. NIH [Online]. DOI: 10.5306/wjco.v3.i10.137 Kulkarni, S.A. and Feng, S.-S. (2013) “Effects of particle size and surface modification on cellular uptake and biodistribution of polymeric nanoparticles for drug delivery,” Pharmaceutical Research, 30(10), pp. 2512–2522. PubMed [Online]. DOI: 10.1007/s11095-012-0958-3 Luminari, S. et al. (2010) “Nonpegylated liposomal doxorubicin (Myocet™) combination (R-comp) chemotherapy in elderly patients with diffuse large B-cell lymphoma (DLBCL): Results from the phase II EUR018 trial,” Annals of Oncology, 21(7), pp. 1492–1499. ScienceDirect [Online]. DOI: 10.1093/annonc/mdp544 Shoji, T. et al. (2014) “A phase I study of irinotecan and pegylated liposomal doxorubicin in recurrent ovarian cancer (Tohoku Gynecologic Cancer Unit 104 study),” Cancer Chemotherapy and Pharmacology, 73(5), pp. 895–901. SpringerLink [Online]. DOI: 10.1007/s00280-014-2418-8 Tardi, P., Boman, N. and Cullis, P. (1985) “Liposomal Doxorubicin,” Journal of Drug Targeting, 4(3), pp. 129–140. DOI: 10.3109/10611869609015970