Water-immiscible bio-inert coatings and film formation from aqueous dispersions of poly (2-methoxyethyl acrylate) microspheres

Significance 

In recent years, advances in biomedical research require that novel biomaterials and their coatings should exhibit biocompatibility without interaction with biological components. A wide variety of synthetic polymers that meet this criterion is available for the formation of bio-inert surfaces. However, a great deal of these polymers is soluble in water and possess the local structure of water at a polymer interface, which is crucial for the sought after bio-inertness, since water adsorption influences protein adsorption/cell adhesion when a polymer make contact with blood. This drawback has led to the fabrication of a novel bio-inert polymer that exhibits poor water solubility: the poly (2-methoxyethyl acrylate). This novel polymer has a low glass transition temperature that yield a rubber-like state under body environment. More so, poly (2-methoxyethyl acrylate)-based microspheres have been synthesized as they are considered promising colloidal carriers. Conversely, little has been done on the rubber properties of the poly (2-methoxyethyl acrylate)-based microspheres with respect to film formation despite the fact that the polymer microspheres are suitable for the formation of tailorable films.

Researchers led by Professor Daisuke Suzuki at Shinshu University in Japan developed an adhesive, flexible, and transferable free-standing film composed of soft poly (2-methoxyethyl acrylate) microspheres formed and characterized under mild and biocompatible conditions for applications in biomedical engineering. They aimed at clarifying the properties of pure poly (2-methoxyethyl acrylate) microspheres in terms of protein adsorption resistance and film formation. Their work is now published in the research journal, Colloids and Surfaces B: Bio-interfaces.

Briefly, the empirical procedure commenced with the synthesis of monodisperse poly (2-methoxyethyl acrylate) microspheres via aqueous free-radical, soap-free precipitation/soap-free emulsion polymerization techniques. The team opted for these techniques since they result in uniformly sized microspheres that are obtained without the use of any dispersion stabilizers, such as surfactants and other polymers. The research team then characterized the plasma protein adsorption behavior of the poly (2-methoxyethyl acrylate) and other typical polymer microspheres in terms of the amounts of plasma proteins adsorbed by the dispersed poly (2-methoxyethyl acrylate) microspheres in a bulk solution.

The researchers were able to observe that non-functionalized and non-cross-linking poly (2-methoxyethyl acrylate) microspheres could be obtained by aqueous soap-free precipitation and emulsion polymerization in water. These poly (2-methoxyethyl acrylate) microspheres showed a suppression of non-specific protein adsorption, which was confirmed through a plasma protein adsorption experiment; the adsorption amounts of the human serum albumin, fibrinogen from human plasma, and immunoglobulin G were much lower than those on other surfaces of the polymer microspheres in bulk solution, regardless of the charged state of the poly (2-methoxyethyl acrylate) microspheres.

Daisuke Suzuki and co-workers also observed that the injectable poly (2-methoxyethyl acrylate) dispersion can be applied to form the poly (2-methoxyethyl acrylate) coated substrate, the adhesive and transferable free-standing film. Such diversity in applicability can be attributed to the rubber property of the poly (2-methoxyethyl acrylate) microspheres without any impurities and organic solvents, which are usually used to form the poly (2-methoxyethyl acrylate) chains and their applications. The clean and pure poly (2-methoxyethyl acrylate) microsphere system described within offers new perspectives for applications in biomedical engineering.

Water-immiscible bio-inert coatings and film formation from aqueous dispersions of poly (2-methoxyethyl acrylate) microspheres. Advances in Engineering

About the author

Takuma Kureha is currently carrying out postgraduate studies under the supervision of Prof. Dr. Daisuke Suzuki at Shinshu University, for which he has been awarded a JSPS Research Fellow (DC1). In 2015, he has studied abroad in the group of Prof. Dr. Walter Richtering at the RWTH Aachen (Germany).

His current research is concerned with the separation behavior of hydrogel microspheres in order to control uptake and release. His awards include the RSC Soft Matter Award and The Society of Polymer Science (Japan) Symposium on Macromolecules Poster Award.

About the author

Seina Hiroshige is carrying out postgraduate studies on the synthesis and application of soft and tough elastomer microspheres under the supervision of Prof. Dr. Daisuke Suzuki at Shinshu University. She has received the Research Encouragement Prize form the Society of Polymer Science (Japan).

About the author

Shusuke Matsui is currently endowed with a JSPS research fellowship (DC2) to carry out postgraduate studies on the dynamics of polymeric microspheres on the solid/liquid interface in the group of Prof. Dr. Daisuke Suzuki at Shinshu University (Japan). He has received the Division of Colloid and Surface Chemistry Poster Award, the Society of Polymer Science in Japan Annual Meeting Poster Award, and the Polymer Microspheres Symposium Oral Presentation Award.

About the author

Prof. Dr. Daisuke Suzuki obtained his PhD from Keio University (2007), before he went on to conduct postdoctoral studies at the University of Tokyo (2007-2009) as a JSPS research fellow (PD). He started his independent research career at Shinshu University in 2009 as a tenure-track Assistant Professor, where he was promoted to Associate Professor in 2013.

His current research is focused on the design, synthesis, and assembly of soft hydrogel and elastomer microspheres. His awards include the SPSJ Award for outstanding papers in Polymer Journal (sponsored by ZEON), and the Award for Encouragement of Research in Polymer Science from the Society of Polymer Science (Japan).

About the author

Professor Jian Cao (MIT’95, MIT’92, SJTU’89) is the Cardiss Collins Professor, Director of Northwestern Initiative for Manufacturing Science and Innovation, and an Associate Vice President for Research at Northwestern University. She is the co-corresponding author of this paper.

Her current research on flexible dieless forming, micro-forming, laser ablation processes and additive manufacturing has direct impacts on energy-efficient manufacturing, surface engineering and distributed manufacturing. She has published over 300 technical articles, including over 150 journal articles, 14 book chapters, and over 10 patents. She is a Fellow of ASME, CIRP and SME.

Reference

Takuma Kureha, Seina Hiroshige, Shusuke Matsui, Daisuke Suzuki. Water-immiscible bioinert coatings and film formation from aqueous dispersions of poly (2-methoxyethyl acrylate) microspheres. Colloids and Surfaces B: Bio-interfaces, volume 155 (2017) pages 166–172.

Go To Colloids and Surfaces B: Bio-interfaces

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