Off-Stoichiometry Thiol-Enes (OSTE) - The first polymer system developed for labs-on-chip

The problem: The field of lab-on-chip (LoC) has demonstrated the integration of several chemical functions onto a single chip device, and has evolved as a research field on its own during the past decade, as is illustrated by the more than 10 000 papers published in the field. Nevertheless, the number of commercial LoC products remains very low. To a large extent, this research-to-application gap can be ascribed to the lack of a consistent material and fabrication technology for both academia and production.

OSTE applications

Most of the conceptual microfluidic device development is still done using poly(dimethylsiloxane) (PDMS), which remains the material of choice for proof of concept prototyping since its introduction in the 1990s mainly because of its ease of use and attractive mechanical elastomeric properties. Unfortunately, for most applications a prototype conceptual device based on PDMS needs complete redevelopment to realize a commercial proto- type. The reason is twofold, firstly, because the elastomeric properties are inadequate for many commercial products that need invariable surface chemistry and mechanical strength. Secondly, the PDMS fabrication processes are difficult to scale up and contain assembly steps, such as slow thermal curing or manual handling of thin elastomeric films that are incompatible with medium or large-scale manufacturing.

Objectives

The overall objective of our research is to bridge the “lab-to-fab-gap” and move from today’s use of suboptimal off-the-shelf materials to a novel polymer platform, adapted for rapid prototyping of labs-on-chip but at the same time having material and processing properties compatible with large scale production.

A technological paradigm shift towards a consistent material and manufacturing scheme for LoC production can enable a paradigm shift in terms of commercialization of R&D results, and in terms of enabling the cost-efficient volume manufacturing of high-performance LoCs.

Results

We have developed the first rapid prototyping polymer system specifically addressing many of the shortcomings of PDMS, such as poor mechanical properties, absorption of small molecules and difficulties to permanently modify the surface. The new polymer platform is based on off-stoichiometry thiol-ene (OSTE) chemistry (Carlborg, Lab Chip, 2011). This polymer system is a rapidly UV-curing system allowing for tunable mechanical properties (rubbery-like to thermoplastic-like), tunable surface chemistry (built in molecular surface anchors that can be used for direct and permanent surface modification) and a low-temperature direct bonding process not requiring any surface activation or glues. Moreover the manufacturing process is compatible with standard soft lithography micropatterning. 

OSTE process

The technology has been successfully demonstrated for packaging of biofunctionalised QCM sensors (Sandström, Transducers, 2011), bonding to spotted protein and DNA-microarrays (Carlborg, microTAS, 2011) and wafer-level integration and bonding (Carlborg, microTAS, 2011, Saharil, Lab Chip, 2012).

Current research also focuses on direct micropatterning by lithography and off-stoichiometry thiol-ene-epoxy OSTE(+), which has further advantages such as bonding to almost “everything” as well as no leaching of uncured components (Saharil, MEMS, 2012).

The polymer system has been commercialized and further developed by Mercene Labs. More information can be found on their homepage.

Project members

Tommy Haraldsson

Fredrik Carlborg

Farizah Saharil

Mikael Karlsson

Gaspard Pardon

Niklas Sandström

Journal publications

Conference publications

Projects in Micro- and Nanofluidic systems

Title Date
Micro- and Nanofluidic systems 1475227140000 Sep 30, 2016
Antifouling surfaces 1446548451937 Nov 03, 2015
Synthetic microfluidic paper and lateral flow devices 1475514960000 Oct 03, 2016
THERACAGE - Polymeric cell encapsulation for localized tumour treatment 1517562060000 Feb 02, 2018
Detection of Airborne Viruses 1418319163300 Dec 11, 2014
Advanced PDMS microfabrication 1385650805364 Nov 28, 2013
Off-Stoichiometry Thiol-Enes (OSTE) - The first polymer system developed for labs-on-chip 1385733622048 Nov 29, 2013
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