Engineering Surfaces for Bioconjugation:  Developing Strategies and Quantifying the Extent of the Reactions

Abstract

This study presents two-step and multistep reactions for modifying the surface of plasma-functionalized poly(tetrafluoroethylene) (PTFE) surfaces for subsequent conjugation of biologically relevant molecules. First, PTFE films were treated by a radiofrequency glow discharge (RFGD) ammonia plasma to introduce amino groups on the fluoropolymer surface. This plasma treatment is well optimized and allows the incorporation of a relative surface concentration of approximately 2-3.5% of amino groups, as assessed by chemical derivatization followed by X-ray photoelectron spectroscopy (XPS). In a second step, these amino groups were further reacted with various chemical reagents to provide the surface with chemical functionalities such as maleimides, carboxylic acids, acetals, aldehydes, and thiols, that could be used later on to conjugate a wide variety of biologically relevant molecules such as proteins, DNA, drugs, etc. In the present study, glutaric and cis-aconitic anhydrides were evaluated for their capability to provide carboxylic functions to the PTFE plasma-treated surface. Bromoacetaldehyde diethylacetal was reacted with the aminated PTFE surface, providing a diethylacetal function, which is a latent form of aldehyde functionality. Reactions with cross-linkers such as sulfo-succinimidyl derivatives (sulfo-SMCC, sulfo-SMPB) were evaluated to provide a highly reactive maleimide function suitable for further chemical reactions with thiolated molecules. Traut reagent (2-iminothiolane) was also conjugated to introduce a thiol group onto the fluoropolymer surface. PTFE-modified surfaces were analyzed by XPS with a particular attention to quantify the extent of the reactions that occurred on the polymer. Finally, surface immobilization of fibronectin performed using either glutaric anhydride or sulfo-SMPB activators demonstrated the importance of selecting the appropriate conjugation strategy to retain the protein biological activity.

Amide‐linkage formed between ammonia plasma treated poly(D,L‐lactide acid) scaffolds and bio‐peptides: Enhancement of cell adhesion and osteogenic differentiation in vitro

“…Surface characteristics of scaffolds for bone tissue engineering must support cell adhesion, migration, proliferation, and osteogenic differentiation. [33][34][35][36] Numerous methods of surface modification have been developed. 13,14,19,[37][38][39] In this study, we combine NH 3 plasma treatment with peptides coupling technologies to affect the aforementioned cytobiological behaviors of BMSCs in PDLLA scaffolds.…”

“…It has been proved that the polymers with the amine and amide radicals promote attachment of cells in the culture. 26,31,34,[42][43][44][45] The enriched polar groups on the polymer surface can provide many sites to obtain the ECM proteins by polar interaction and hydrogen bonding 24 or directly induce the interaction of cells with the reactive groups. 45 However, unsuitable prolonging of treatment time may result in loss of new generated polar groups.…”

Control of the blood–polymer interface by plasma treatment

“…25,26 Nitrogen is selected due to the interest in creation of nitrogen-related functional groups onto polymer surfaces aimed to be compatible with a biological environment, since, for example, it is recognized that amino groups provide an excellent basis for subsequent surface modification techniques while they allow to bond biomolecules with high selectivity. 27,28 The gas mixture composition is selected according to previous experiments, allowing the nitrogen species to be the most efficiently activated due to transfer from helium species and inducing efficient surface functionalization. 23 Taking into account the above, the helium flow rate is fixed at 100 cm 3 /min throughout, and treatments under He environment are compared to plasma exposure under He-5% N 2 and He-10%N 2 environment.…”

Orientation and characterization of immobilized antibodies for improved immunoassays (Review)

“…58 For example, lipid PEG, functionalized with maleimide, was incorporated into lipid nanocapsules for coupling thiolated antibodies or Fab 0 . 59 …”