Conducting Polymers with Confined Dimensions: Track‐Etch Membranes for Amperometric Biosensor Applications

Organic conducting polymers can be synthesized inside the pores of a track‐etch membrane, and the resulting hollow tubules are shown to have enhanced electrical properties compared to their corresponding bulk materials. The polymerization of monomers (e.g., pyrrole, thiophenes) inside the confined space of these pores, combined with electrostatic interaction, ensures the alignment of the organic polymers on the interior, leading to higher conductivity. The application of these conducting tubes in the development of amperometric glucose sensors is discussed. Due to the special properties of conducting polymers inside a track‐etch membrane, biosensors with a unique electron‐transfer mechanism have been developed.     

A Radial Flow Microfluidic Device for Ultra‐High‐Throughput Affinity‐Based Isolation of Circulating Tumor Cells

Circulating tumor cells (CTCs) are believed to play an important role in metastasis, a process responsible for the majority of cancer‐related deaths. But their rarity in the bloodstream makes microfluidic isolation complex and time‐consuming. Additionally the low processing speeds can be a hindrance to obtaining higher yields of CTCs, limiting their potential use as biomarkers for early diagnosis. Here, a high throughput microfluidic technology, the OncoBean Chip, is reported. It employs radial flow that introduces a varying shear profile across the device, enabling efficient cell capture by affinity at high flow rates. The recovery from whole blood is validated with cancer cell lines H1650 and MCF7, achieving a mean efficiency >80% at a throughput of 10 mL h^?1 in contrast to a flow rate of 1 mL h^?1 standardly reported with other microfluidic devices. Cells are recovered with a viability rate of 93% at these high speeds, increasing the ability to use captured CTCs for downstream analysis. Broad clinical application is demonstrated using comparable flow rates from blood specimens obtained from breast, pancreatic, and lung cancer patients. Comparable CTC numbers are recovered in all the samples at the two flow rates, demonstrating the ability of the technology to perform at high throughputs.     

Cover Picture: Lithography‐Free,Self‐Aligned Inkjet Printing with Sub‐Hundred‐Nanometer Resolution (Adv. Mater. 8/2005)

The inherently low resolution of inkjet printing on unpatterned surfaces can be overcome by selective surface modification of a first printed pattern, resulting in hydrophobic repulsion of subsequently deposited aqueous polymer dispersions. This technique, reported by Sirringhaus and co‐workers on p. 997, is capable of achieving sub‐100 nm resolution without any lithographic step. The cover shows an array of polymer transistors patterned with this method on three different length scales, as well as a schematic of the process.     

Nanotentacle‐Structured Magnetic Particles for Efficient Capture of Circulating Tumor Cells

Circulating tumor cells (CTCs) have attracted considerable attention as promising markers for diagnosing and monitoring the cancer status. Despite many technological advances in isolating CTCs, the capture efficiency and purity still remain challenges that limit clinical practice. Here, the construction of “nanotentacle”‐structured magnetic particles using M13‐bacteriophage and their application for the efficient capturing of CTCs is demonstrated. The M13‐bacteriophage to magnetic particles followed by modification with PEG is conjugated, and further tethered monoclonal antibodies against the epidermal receptor 2 (HER2). The use of nanotentacle‐structured magnetic particles results in a high capture purity (>45%) and efficiency (>90%), even for a smaller number of cancer cells (≈25 cells) in whole blood. Furthermore, the cancer cells captured are shown to maintain a viability of greater than 84%. The approach can be effectively used for capturing CTCs with high efficiency and purity for the diagnosis and monitoring of cancer status.