Jörg Nestler

A new technology platform for fully integrated polymer based micro optical fluidic systems

Abstract This paper describes a new technology platform for polymeric micro optical fluidic systems. The platform consists of active and passive optical and fluidic elements for a surface plasmon resonance (SPR) biosensor for the detection of proteins. The platform includes the integration of polymer light emitting diodes, polymer photodiodes as well as polymer based fluidic valves and pressure generation elements. Surface functionalization for micro optical and micro fluidic parts as well as advanced manufacturing methods are other important parts of the presented technology platform.

Integration of an Optical Ring Resonator Biosensor into a Self-Contained Microfluidic Cartridge with Active, Single-Shot Micropumps

While there have been huge advances in the field of biosensors during the last decade, their integration into a microfluidic environment avoiding external tubing and pumping is still neglected. Herein, we show a new microfluidic design that integrates multiple reservoirs for reagent storage and single-use electrochemical pumps for time-controlled delivery of the liquids. The cartridge has been tested and validated with a silicon nitride-based photonic biosensor incorporating multiple optical ring resonators as sensing elements and an immunoassay as a potential target application. Based on experimental results obtained with a demonstration model, subcomponents were designed and existing protocols were adapted. The newly-designed microfluidic cartridges and photonic sensors were separately characterized on a technical basis and performed well. Afterwards, the sensor was functionalized for a protein detection. The microfluidic cartridge was loaded with the necessary assay reagents. The integrated pumps were programmed to drive the single process steps of an immunoassay. The prototype worked selectively, but only with a low sensitivity. Further work must be carried out to optimize biofunctionalization of the optical ring resonators and to have a more suitable flow velocity progression to enhance the system’s reproducibility.

Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate

A microfluidic setup which enables on-line monitoring of residues of malachite green (MG) using surface-enhanced Raman scattering (SERS) is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate.

Laser based dry integration of rolled-up nanomembranes into polymer substrates

A strategy for the integration of rolled-up micro scaled sensor devices on polymer substrates using laser micromachining and laser welding was developed and investigated. Using inexpensive polycarbonate substrates, this strategy thereby focuses on the utilization of such sensor elements in low cost yet fully integrated point-of-care Lab-on-a-Chip systems. In contrast to a previously developed MEMS-based “wet” integration method using a large number of photolithography steps involving the usage of organic solvents [1], the here presented “dry” integration method needs first of all less processing steps. Furthermore it eliminates the direct contact of the inner tube walls with the utilized solvents during the previously developed integration process. This leads to the possibility of applying a broad range of bio-functionalization on the surface of the nanomembranes that would be destroyed by the “wet” integration method.A strategy for the integration of rolled-up micro scaled sensor devices on polymer substrates using laser micromachining and laser welding was developed and investigated. Using inexpensive polycarbonate substrates, this strategy thereby focuses on the utilization of such sensor elements in low cost yet fully integrated point-of-care Lab-on-a-Chip systems. In contrast to a previously developed MEMS-based “wet” integration method using a large number of photolithography steps involving the usage of organic solvents [1], the here presented “dry” integration method needs first of all less processing steps. Furthermore it eliminates the direct contact of the inner tube walls with the utilized solvents during the previously developed integration process. This leads to the possibility of applying a broad range of bio-functionalization on the surface of the nanomembranes that would be destroyed by the “wet” integration method.

A Costing Methodology for Products Based on Emerging Micro and Nano Manufacturing Technologies

This paper introduces a simple costing methodology adopted in a European research project for comparing the cost of alternative manufacturing routes when designing new innovative micro and nano products. This methodology has been specifically developed to assess the product development implication of emerging manufacturing technologies, which might still be under development in research labs. To illustrate the proposed methodology, its application to the costing of a microfluidic system for a lab-on-chip device is described, highlighting how such early cost estimation can be considered concurrently with research challenges when making design decisions at the research stage.

Micro/nano technologies towards smart systems integration

The micro and nano system technologies as well as electronics are playing a key role in todays product development and industrial progress. They enable the integration of mechanical, electrical, optical, chemical, biological and other functions into a very small space with dimensions ranging from sub micrometers up to some millimeters. This paper presents different examples of MEMS sensors and systems developed at Fraunhofer ENAS and Chemnitz University of Technology. It starts with silicon based technologies applied for MEMS laser displays and miniaturized MEMS spectrometer. The integration of new materials and new technologies is shown for point of care diagnostics.