Reactive amine surfaces for biosensor applications, prepared by plasma-enhanced chemical vapour modification of polyolefin materials

Abstract

Functionalization of the plastic chips for selective immobilization of biomolecules is one of the key challenges to be addressed in commercialization of the next-generation point-of-care (POC) diagnostics devices. Multistep liquid-phase deposition process requires a large quantity of solvent to be used in anhydrous conditions, providing quantity of industrial liquid waste. We, in this work, have demonstrated a solventless plasma-based process that integrates low-cost, high throughput, high reproducibility and ecofriendly process for the functionalization of POC device platforms. Amine functionalities have been deposited by plasma-enhanced chemical vapour deposition 2 (PECVD) using a new precursor. For a successful and efficient plasma functionalization process, an understanding of the influence of plasma process parameters on the surface characteristics is essential. The influence of the plasma RF power and the deposition time on the deposited amount of amino functionalities and on their capacity to immobilize nano-objects (i.e., nanoparticles) and biomolecules (i.e. DNA) was examined. Surfacial properties were related to the binding capacity of the films and to the amino content, as revealed by the Ònanoparticle approachÓ and DNA attachment experiments. The key process determinants were to have a sufficient power in the plasma to activate and partially fragment the monomer but not too much as to lose the reactive amine functionality, and sufficient deposition time to develop a reactive layer but not to consume or erode the amine reactivity. An immunoassay performed using human immunoglobulin (IgG) as a model analyte shows an improvement of the detection limit by two orders of magnitude beyond that obtained using devices activated by liquid-phase reaction.

Highly transparent and reproducible nanocrystalline ZnO and AZO thin films grown by room temperature pulsed-laser deposition on flexible Zeonor plastic substrates

“…This is compatible with the high sensitivity of the ZnO surface wettability on both exposure to near ultraviolet radiation [46] and chemical contamination [47]. A WCA of 92.0° has been measured for the bare 1060 R Zeonor surface, which is therefore hydrophobic [25,26,28]. Overall, it is seen that the main effect of ZnO and AZO thin film deposition is to increase the hydrophobicity of the Zeonor surface.…”

“…Zeonor is the material of choice for many applications in microfluidics [26], biodiagnostics [27] and biosensors [28], as well as in stringent optics applications such as high density DVDs, liquid crystal displays and plastic optical fibers [25,29]. These and other state-ofthe-art devices may variously require the deposition of electrical contacts and/or high-quality optical coatings that could potentially be achieved with ZnO and AZO thin films.…”

Plasma functionalization of AFM tips for measurement of chemical interactions

“…Also, amino-functionalization of surfaces has previously been demonstrated using PECVD from ethylenediamine (EDA) or allylamine precursor on glass, silicon, or polypropylene [24,25]. Recently, an alternative precursor, (3-aminopropyl)triethoxysilane (APTES), was highlighted as appropriate for cycloolefin copolymers amination [26,27]. Due to the presence of Si-O groups this molecule can create chemical bonding to plasma-activated surfaces, allowing a good adhesion, stability, and high amino content of the coating.…”

Total internal reflection ellipsometry as a label-free assessment method for optimization of the reactive surface of bioassay devices based on a functionalized cycloolefin polymer

“…Several techniques have been proposed to functionalize ZR with carboxylic or amine functional groups using both standard liquid phase chemistry as well as plasma enhanced chemical vapour deposition (PECVD) [3][4][5][6][7][8][9]. The quality of the functional films produced on ZR surface has a significant influence on the performance of the biosensor devices.…”