Fabrication of Functional Molecularly Imprinted Materials using Nanoparticle Building Blocks

• Molecularly imprinted polymers (MIPs) have attracted great interest in many applications including bioseparation, chemical sensing, catalysis, drug delivery, etc. Recently, molecularly imprinted nanoparticles have become accessible due to a number of synthetic methods that have been developed. The high molecular binding selectivity, fast binding kinetics and colloidal stability make MIP nanoparticles ideal building blocks for fabrication of new multifunctional materials. As examples, magnetic susceptibility, fluorescence response, plasmonic enhancements have been integrated into MIP materials by different physical entrapments or chemical conjugation methods. In this thesis, the use of nanoparticle building blocks for preparation of functional MIP materials is studied. First, different chemical conjugation methods are investigated to allow MIP nanoparticles to be covalently linked to various materials extending from fluorescent molecules, magnetic nanoparticles, to hydrophilic cryogels. Click chemistry based on Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction and amine-glutaraldehyde crosslinking reaction are used to conjugate core-shell MIP nanoparticles with other functional components. To enable ordinary MIP nanoparticles to act as useful building blocks, a simple photo-conjugation method based on perfluorophenyl azide (PFPA) has been developed. The composite materials obtained by the different chemical conjugation methods display not only high molecular selectivity, but also additional attractive features, such as magnetic susceptibility, fluorescence response, as well as macroporous structure allowing purification of complex samples. In the second part, inorganic nanoparticles are used as surfactants to stabilize oil-in-water emulsion (Pickering emulsion) to synthesize water-compatible MIP microspheres. The new MIP material exhibits high molecular selectivity and allows direct separation of target analytes in water. The chemical conjugation methods developed in this thesis have a general applicability and should provide convenient means to developing other functional materials and devices. The use of nanoparticle surfactants in molecular imprinting has enabled direct molecular separation under pure aqueous condition. The new synthetic approach based on Pickering emulsion polymerization opens new possibilities for molecularly imprinted materials, particularly in the area of bioseparation and sensing.

• Popular Abstract in Undetermined Nanoparticles have attracted great interest in biomedicine and material science due to their unique and unconventional properties. Polymer nanoparticles containing pre-designed molecular recognition sites can be synthesized using molecular imprinting technique. Molecularly imprinted polymers (MIPs) have high affinity and selectivity that are similar to antibodies, and have been named as artificial antibodies. Because of their very high stability and low production cost, MIP materials can be used to replace antibodies in many practical applications, e.g. product purification, diagnostics, removal of environmental pollutants, and in different analytical systems for analysis of complex samples. In this thesis, I discuss how new functions (such as magnetic susceptibility, fluorescence, and catalytic properties) can be introduced to MIP materials using highly efficient chemical conjugation methods. The new composite materials obtained not only possess high molecular recognition selectivity, but also become easy to handle in practical applications. The main focus is the use of nanoparticles as building blocks to prepare new imprinted materials with novel properties, e.g. to enable direct molecular separation in water. Firstly, different strategies to immobilize MIP nanoparticles through physical entrapment are reviewed. Secondly, several chemical approaches are introduced, where the imprinted nanoparticles are conjugated with other functional nanoparticles through covalent bonding. During the preparation, the nanoparticles are first modified with specific chemical groups, which allow the nanoparticles to react with other nanoparticles (Paper I). New water-compatible crosslinking reactions and light activated crosslinking reactions are investigated (Paper I, V). The MIP composites obtained are characterized using different analytical techniques. Several multifunctional materials have been developed in this thesis, including magnetic composites allowing fast separation (Paper II, V), macroporous affinity gels enabling treatment of complex samples (Paper IV), fluorescent and multifunctional microcontainers as new sensing and delivery systems (Paper III). In the last, fully water-compatible MIP beads are prepared from nanoparticle-stabilized emulsions (Paper VI).

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Molecularly imprinted polymers

magnetic susceptibility

click chemistry

PFPA

Pickering emulsion

chemical conjugation

Publikations- och innehållstyp

dok (ämneskategori)

vet (ämneskategori)