<p>Slp-coated liposomes for drug delivery and biomedical applications: potential and challenges</p>

Abstract

Slp forms a crystalline array of proteins on the outermost envelope of bacteria and archaea with a molecular weight of 40-200 kDa. Slp can self-assemble on the surface of liposomes in a proper environment via electrostatic interactions, which could be employed to functionalize liposomes by forming Slp-coated liposomes for various applications. Among the molecular characteristics, the stability, adhesion, and immobilization of biomacromolecules are regarded as the most meaningful. Compared to plain liposomes, Slp-coated liposomes show excellent physicochemical and biological stabilities. Recently, Slp-coated liposomes were shown to specifically adhere to the gastrointestinal tract, which was attributed to the "ligand-receptor interaction" effect. Furthermore, Slp as a "bridge" can immobilize functional biomacromolecules on the surface of liposomes via protein fusion technology or intermolecular forces, endowing liposomes with beneficial functions. In view of these favorable features, Slp-coated liposomes are highly likely to be an ideal platform for drug delivery and biomedical uses. This review aims to provide a general framework for the structure and characteristics of Slp and the interactions between Slp and liposomes, to highlight the unique properties and drug delivery as well as the biomedical applications of the Slp-coated liposomes, and to discuss the ongoing challenges and perspectives.

Nanoplatforms for Sepsis Management: Rapid Detection/Warning, Pathogen Elimination and Restoring Immune Homeostasis

“…Liposomes are nanoscale lipid bilayer vesicles composed of phospholipids and cholesterol, which have advantages of high drug encapsulation, favorable biocompatibility and biodegradability, reduction of drug toxicity, slow-release behavior, passive targeting, ease of surface engineering, and optimizing pharmacokinetic properties, and have been widely investigated as drug carriers for delivery of small molecules, peptides, proteins, genes, and antibodies, with kinds of liposomal products approved such as liposomal DOX and liposomal amphotericin B [ 44 , 94 , 95 ]. It has a hydrophilic core and a hydrophobic layer, thus enabling favorable entrapment ability for both hydrophilic and lipophilic drugs [ 44 ]. Due to their broad-panel drug encapsulation, liposomes have already been extended to establish combinatorial therapeutics.…”

“…Shi and coworkers proposed a combinatorial strategy that integrated PUFAylation prodrug technique into liposomal scaffold, thereby resulting in a cabazitaxel prodrug-formulated liposome (lipoprodrug) which exhibited excellent in vivo tolerability, targeted accumulation in tumor tissues via EPR effect, and prolonged half-life [ 98 ]. Nevertheless, conventional liposomes usually require additional surface modifications to overcome potential disadvantages such as clearance by reticuloendothelial system (RES), drug leakage, poor stability, undesirable tissue distribution [ 44 ]. PEGylation is the representative strategy for surface engineering of liposomes to avoid RES barrier and favor stability; however, it will impede the normal release of therapeutic agents and cell uptake [ 44 ].…”

“…Nevertheless, conventional liposomes usually require additional surface modifications to overcome potential disadvantages such as clearance by reticuloendothelial system (RES), drug leakage, poor stability, undesirable tissue distribution [ 44 ]. PEGylation is the representative strategy for surface engineering of liposomes to avoid RES barrier and favor stability; however, it will impede the normal release of therapeutic agents and cell uptake [ 44 ]. Alternative strategy proposed by Tang and coworkers might be able to resolve this paradox [ 99 ].…”

“…The polymeric micelle paclitaxel was approved in Korea for the treatment of breast cancer and NSCLC [ 43 ]. In addition to systemic administration, bacterial surface protein-functionalized liposomes potentially promote the oral delivery of biomacromolecules ( e.g., vaccines) by enhancing gastrointestinal adhesion and physicochemical stability [ 44 , 45 ]. Additionally, nanoemulsions have widely been employed to overcome poor solubility, thus improving the bioavailability of cargo drugs, particularly the biopharmaceutical classification system (BCS) II drugs [ 46 ].…”

Metabolism Balance Regulation via Antagonist‐Functionalized Injectable Microsphere for Nucleus Pulposus Regeneration

“…In Vitro Release Profile of rhsTNFRII: A total of 30 mg grafted microspheres (theoretically containing 100 ng rhsTNFRII) were immersed in a 50 mL centrifuge tube containing 10 mL PBS, then placed on a 37 °C shaker. At specified time points (1, 2, 3,5,7,9,12,15,18,23,28, and 35 days), a sample of buffer was collected and stored at 20 °C prior to measurement. Each removed aliquot was replaced with fresh PBS.…”