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In recent decades, polymers have experienced a radical evolution: from being used as inexpensive materials in the manufacturing of simple appliances to be designed as nanostructured devices with important applications in many leading fields, such as biomedicine at the nanoscale. Within this context, polymeric free-standing nanomembranes - self-supported quasi-2D structures with a thickness ranging from similar to 10 to a few hundreds of nanometers and an aspect ratio of size and thickness greater than 10(6) - are emerging as versatile elements for applications as varied as overlapping therapy, burn wound infection treatment, antimicrobial platforms, scaffolds for tissue engineering, drug-loading and delivery systems, biosensors, etc. Although at first, a little over a decade ago, materials for the fabrication of free-standing nanosheets were limited to biopolymers and insulating polymers that were biodegradable, during the last five years the use of electroactive conducting polymers has been attracting much attention because of their extraordinary advantages in the biomedical field. In this context, a systematic review of current research on polymeric free-standing nanomembranes for biomedical applications is presented. Moreover, further discussion on the future developments of some of these exciting areas of study and their principal challenges is presented in the conclusion section.

A new bis-thienyl type monomer with preformed azomethine linkages (AzbT) was chemically synthesized and, subsequently, electro-copolymerized with 2,2' : 5', 2 ''-terthiophene (Th-3). AzbT : Th-3 mixtures with different molar ratios (i.e. 50 : 50, 60 : 40 and 80 : 20) were considered, the resulting thin films being made of random insoluble copolymers, P(AzbT-co-Th-3)s. The content of AzbT in P(AzbT-co-Th-3) s was found to increase with the AzbT : Th-3 molar ratio in the electropolymerization medium. Furthermore, characterization of the different copolymers suggests the existence of several concomitant processes in the reaction medium. Thus, depending on the composition of the reaction medium, AzbT worked as a co-monomer and/or as a dopant for the growing polymer chains. The morphology of the films evolved from a porous multi-level surface to a more compact and flat globular structure with increasing AzbT content. On the other hand, the electrochemical and optical properties were also influenced by the AzbT : Th-3 ratio. Cytotoxicity and cell adhesion and proliferation tests, which were performed using human osteosarcoma and monkey kidney epithelial cell lines (MG-63 and Vero, respectively), revealed that P(AzbT-co-Th-3) matrices can be potentially applied as bioactive substrates. This behaviour was especially relevant for the 80 : 20 copolymer, which exhibits optical and electrochemical properties in the range of polythiophene derivatives, suggesting that it is a promising functional biomaterial.