The hydration lubrication paradigm,whereby hydration layers are both strongly held by the charges they surround,and so can support large pressures without being squeezed out,and at the same time remain very rapidly re...The hydration lubrication paradigm,whereby hydration layers are both strongly held by the charges they surround,and so can support large pressures without being squeezed out,and at the same time remain very rapidly relaxing and so have a fluid response to shear,provides a framework for understanding,controlling,and designing very efficient boundary lubrication systems in aqueous and biological media.This review discusses the properties of confined water,which-unlike organic solvents-retains its fluidity down to molecularly thin films.It then describes lubrication by hydrated ions trapped between charged surfaces,and by other hydrated boundary species including charged and zwitterionic polymer brushes,surfactant monolayers,liposomes,and biological macromolecules implicated in synovial joint lubrication.Finally,challenges and prospects for future development of this new boundary lubrication approach are considered.展开更多
Liposomes mimic natural cell membranes and have long been investigated as drug carriers due to excellent entrapment capacity, biocompatibility and safety. Despite the success of parenteral liposomes,oral delivery of l...Liposomes mimic natural cell membranes and have long been investigated as drug carriers due to excellent entrapment capacity, biocompatibility and safety. Despite the success of parenteral liposomes,oral delivery of liposomes is impeded by various barriers such as instability in the gastrointestinal tract,difficulties in crossing biomembranes, and mass production problems. By modulating the compositions of the lipid bilayers and adding polymers or ligands, both the stability and permeability of liposomes can be greatly improved for oral drug delivery. This review provides an overview of the challenges and current approaches toward the oral delivery of liposomes.展开更多
文摘The hydration lubrication paradigm,whereby hydration layers are both strongly held by the charges they surround,and so can support large pressures without being squeezed out,and at the same time remain very rapidly relaxing and so have a fluid response to shear,provides a framework for understanding,controlling,and designing very efficient boundary lubrication systems in aqueous and biological media.This review discusses the properties of confined water,which-unlike organic solvents-retains its fluidity down to molecularly thin films.It then describes lubrication by hydrated ions trapped between charged surfaces,and by other hydrated boundary species including charged and zwitterionic polymer brushes,surfactant monolayers,liposomes,and biological macromolecules implicated in synovial joint lubrication.Finally,challenges and prospects for future development of this new boundary lubrication approach are considered.
基金financially supported by National Natural Science Foundation of China (81573363 and 81690263)National Key Basic Research Program (2015CB931800)
文摘Liposomes mimic natural cell membranes and have long been investigated as drug carriers due to excellent entrapment capacity, biocompatibility and safety. Despite the success of parenteral liposomes,oral delivery of liposomes is impeded by various barriers such as instability in the gastrointestinal tract,difficulties in crossing biomembranes, and mass production problems. By modulating the compositions of the lipid bilayers and adding polymers or ligands, both the stability and permeability of liposomes can be greatly improved for oral drug delivery. This review provides an overview of the challenges and current approaches toward the oral delivery of liposomes.
