Penn University A recent experiment undertaken by the University of Pennsylvania has apparently developed a library, of synthetic biomaterials that mimic cellular membranes. This may aid in targeting accurate delivery of cancer drugs, gene therapy, proteins, imaging and diagnostic agents and cosmetics safely to the body in the emerging field called nanomedicine.

A novel description, which probably included the preparation, structure, self-assembly, and mechanical properties of vesicles and other selected complex nano-assemblies made from Janus dandrimers appeared in the study. Dendrimersomes may be identical to Janus dendrimers. As the dendrimersomes are stable, bilayer vesicles that are quickly formed from the exact chemical composition of Janus dendrimers.

Percec, the P. Roy Vagelos Chair and Professor of Chemistry at Penn shared, “Dendrimersomes marry the stability and mechanical strength obtainable from polymersomes, vesicles made from block copolymers, with the biological function of stabilized phospholipid liposomes, but with superior uniformity of size, ease of formation and chemical functionalization.”

A myriad of bilayer capsule populations was registered by the study authors. These populations appeared to be uniform in size, stable in time in a large variety of media and temperatures that are tunable by temperature and chemistry with superior mechanical properties to regular liposomes and impermeable to encapsulated compounds. They may not alter their self-assembly and yet have the capacity to incorporate pore-forming proteins. Further they seem to assemble with structure-directing phospholipids, block copolymers and offer a molecular periphery suitable for chemical functionalization

Hammer, the Alfred G. and Meta A. Ennis Professor of Bioengineering at Penn commented, “These materials show special promise because their membranes are the thickness of natural bilayer membranes, but they have superior and tunable materials properties. Because of their membrane thickness, it will be more straightforward to incorporate biological components into the vesicle membranes, such as receptors and channels.”

The investigators chemically combined hydrophilic and hydrophobic dendrons to create amphiphilic Janus dendrimers with a rich palette of morphologies. This included cubosomes, disks, tubular vesicles and helical ribbons and confirmed the assembled structures using cryogenic transmission electron microscopy and fluorescence microscopy.

Bates, the Regents Professor and Head of the Chemical Engineering and Materials Science Department at the University of Minnesota quoted, “No other single class of molecules including block copolymers and lipids is known to assemble in water into such a diversity of supramolecular structures.”

Biological membranes are possibly mimicked by self-assembled nanostructures, obtained from natural and synthetic amphiphiles. These enable the targeted delivery of drugs, nucleic acids, proteins, gene therapy and imaging agents for diagnostic medicine. Molecular arrangements combine to function as safe biological carriers while carrying payload within. But it is very difficult to develop these arrangements.

The study is published in the current issue of the journal Science.