TECHNOLOGY: Block Copolymers

A monomer is a small chemical building block that can chemically bond with other monomers to form more complex structures called polymers (i.e. A-A-A-A-A-A). While many polymers consist of repeats of the same monomer, some called copolymers are the result of two or more different monomers linking together in chains (i.e. A-B-A-A-B-B). Block copolymers are examples of copolymers that can be joined to eachother to form a meta-structure with multiple domains (see figure). A recent paper published in ACS Nano has demonstrated the use of block copolymers in a nanofilm for coating medical devices.In this paper, Dean Ho, et al. add a polymethyloxazoline-polydimethylsiloxan- polymethyloxazoline (PMOXA-PDMS-PMOXA) copolymer with dexamethazone - together referred to as PolyDex - to an implant using a method called Langmuir-Blodgett deposition. The PolyDex was able to "cloak" the implant as it was found to be necessary and sufficient to prevent immune response from cells in normal mice after the implantation of two polyethylene disks.

This PolyDex nanofilm can contribute significantly in the medical device field as devices become smaller and more fragile. The ability of these nanofilms to prevent the accumulation of inflammatory cells may help protect implants from post-implantation damage and increase the mortality of implants in the future. Moreover, this coating may aid in the reduction of overall inflammation of the implant site that may reduce further complications that occur after surgeries. The small thickness of these films at 4 nanometers per layer will make this film extremely versitile as it will allow manufacturers to apply it to the smallest of implants.

While these nanofilms are still very early in development, they show great promise in medical devices, for which inflammation is an all too common issue.

(FIGURE from http://www.warwickeffectpolymers.co.uk/)