Conducting Polymer Microcups for Organic Bioelectronics and Drug Delivery Applications

An ideal neural device enables long‐term, sensitive, and selective communication with the nervous system. To accomplish this task, the material interface should mimic the biophysical and the biochemical properties of neural tissue. By contrast, microfabricated neural probes utilize hard metallic conductors, which hinder their long‐term performance because these materials are not intrinsically similar to soft neural tissue. This study reports a method for the fabrication of monodisperse conducting polymer microcups. It is demonstrated that the physical surface properties of conducting polymer microcups can be precisely modulated to control electrical properties and drug‐loading/release characteristics.     

Inside Front Cover: Conducting‐Polymer Nanotubes for Controlled Drug Release (Adv. Mater. 4/2006)

Martin and co‐workers report on p. 405 that nanotubes formed from the conducting polymer poly(3,4‐ethylenedioxythiophene) (PEDOT), as shown on the inside cover, can be used for the controlled release of anti‐inflammatory drugs. The fabrication process includes electrospinning of a biodegradable polymer, either poly(L ‐lactide) or poly(lactide‐co‐glycolide), into which the required drug is incorporated, followed by electrochemical deposition of the conducting polymer around the drug‐loaded electrospun nanofibers. Drug release from the nanotubes is achieved by external electrical stimulation of the nanotubes.     

Bio/Abiotic Interface Constructed from Nanoscale DNA Dendrimer and Conducting Polymer for Ultrasensitive Biomolecular Diagnosis

For sensors detecting immobilized biomarkers, the interface between the surface and the fluid medium plays an important role in determining the levels of signal and noise in the electrochemical detection process. When protein is directly immobilized on the metal electrode, denaturation of the protein by surface–protein interaction results in low activity and low signal level. A conducting polymer‐based interface can prevent the protein conformation change and alleviate this problem. A DNA dendrimer is introduced into the interfacial film on the sensor surface to further improve the sensor performance. DNA dendrimer is a nanoscale dendrite constructed of short DNA sequences, which can be easily incorporated into the abiotic conducting polymer matrix and is biocompatible with most biological species. In this work, DNA dendrimer and polypyrrole (DDPpy) form the bio/abiotic interface on electrochemical sensors. Detection of two salivary protein markers (IL‐8 and IL‐1β) and one mRNA salivary marker (IL‐8) is used to demonstrate the efficiency of the DDPpy sensor. A limit of detection (LOD) of protein of 100–200 fg mL^?1 is achieved, which is three orders of magnitude better than that without the DNA dendrimer interface. An LOD of 10 aM is established for IL‐8 mRNA. The typical sample volume used in the detection is 4 µL, thus the LOD reaches only 25 target molecules (40 yoctomole).