An official website of the United States government
ABSTRACT We continue to investigate the design, synthesis, and characterization of electrically and ionically active conjugated polythiophene copolymers for integrating a variety of biomedical devices with living tissue. This paper will describe some of our most recent results, including the development of several new monomers that can tailor the surface chemistry, adhesion, and biointegration of these materials with neural cells. Our efforts have focused on copolymers of 3,4 ethylenedioxythiophene (EDOT), functionalized variants of EDOT (including EDOT-acid and the trifunctional EPh), and dopamine (DOPA). The resulting PEDOT-based copolymers have electrical, optical, mechanical, and adhesive properties that can be precisely tailored by fine tuning the chemical composition and structure. Here we present results on EDOT-dopamine bifunctional monomers and their corresponding polymers. We discuss the design and synthesis of an EDOT-cholesterol that combines the thiophene with a biological moiety known to exhibit surface-active behaviour. We will also introduce EDOT-aldehyde and EDOT-maleimide monomers and show how they can be used as the starting point for a wide variety of functionalized monomers and polymers.
more »
« less
A Universal Coating Strategy for Controllable Functionalized Polymer Surfaces
Abstract Development of a universal and stable surface coating, irrespective of surface chemistry or material characteristics, is highly desirable but has proved to be extremely challenging. Conventional coating strategies including the commonly used catechol surface coating are limited to either a certain type of substrates or weak and unreliable surface bonding. Here, a simple, robust, and universal surface coating method capable for attaching any stimuli‐responsive glycidyl methacrylate (GMA)‐based copolymer, consisting of one surface‐adhesive moiety of epoxy groups and one stimuli‐responsive moiety, to any type of hydrophobic and hydrophilic surfaces via a one‐step ring‐opening reaction is proposed and demonstrated. The resultant GMA‐based copolymers are not only strongly adhered on different substrates (e.g., silicon, polypropylene, polyvinyl chloride, indium tin oxide, polyethylene terephthalate, aluminum, glass, polydimethylsiloxane, and even polyvinylidene fluoride with low surface energy), but also are possessed distinct thermal‐, pH‐, and salt‐responsive functions of bacterial killing, bacterial releasing, tunable multicolor fluorescence emission, and heavy metal detection. This coating method is also compatible with the directional quaternization of GMA‐based copolymers for further improving surface adhesion and functionality. This study provides a simple yet universal coating method to solve the long‐standing challenge of robust integration of stimuli‐responsive polymers with strong adhesion between various polymers and substrates.
more »
« less
- Award ID(s):
- 1825122
- PAR ID:
- 10456269
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 30
- Issue:
- 40
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Known for their adaptability to surroundings, capability of transport control of molecules, or the ability of converting one type of energy to another as a result of external or internal stimuli, responsive polymers play a significant role in advancing scientific discoveries that may lead to an array of diverge applications. This review outlines recent advances in the developments of selected commodity polymers equipped with stimuli‐responsiveness to temperature, pH, ionic strength, enzyme or glucose levels, carbon dioxide, water, redox agents, electromagnetic radiation, or electric and magnetic fields. Utilized diverse applications ranging from drug delivery to biosensing, dynamic structural components to color‐changing coatings, this review focuses on commodity acrylics, epoxies, esters, carbonates, urethanes, and siloxane‐based polymers containing responsive elements built into their architecture. In the context of stimuli‐responsive chemistries, current technological advances as well as a critical outline of future opportunities and applications are also tackled.more » « less
-
We demonstrate a single-component hydrophilic photocrosslinkable copolymer system that incorporates all critical functionalities into one chain. This design allows for the creation of uniform functional organic coatings on a variety of substrates. The copolymers were composed of a poly(ethylene oxide)-containing monomer, a monomer that can release a primary amine upon UV light, and a monomer with reactive epoxide or cyclic dithiocarbonate with a primary amine. These copolymers are easily incorporated into the solution-casting process using polar solvents. Furthermore, the resulting coating can be readily stabilized through UV light-induced crosslinking, providing an advantage for controlling the surface properties of various substrates. The photocrosslinking capability further enables us to photolithographically define stable polymer domains in a desirable region. The resulting copolymer coatings were chemically versatile in immobilizing complex molecules by (i) post-crosslinking functionalization with the reactive groups on the surface and (ii) the formation of a composite coating by mixing varying amounts of a protein of interest, i.e., fish skin gelatin, which can form a uniform dual crosslinked network. The number of functionalization sites in a thin film could be controlled by tuning the composition of the copolymers. In photocrosslinking and subsequent functionalizations, we assessed the reactivity of the epoxide and cyclic dithiocarbonate with the generated primary amine. Moreover, the orthogonality of the possible reactions of the presented reactive functionalities in the crosslinked thin films with complex molecules is assessed. The resulting copolymer coatings were further utilized to define a hydrophobic surface or an active surface for the adhesion of biological objects.more » « less
-
Tissue regeneration requires 3-dimensional (3D) smart materials as scaffolds to promote transport of nutrients. To mimic mechanical properties of extracellular matrices, biocompatible polymers have been widely studied and a diverse range of 3D scaffolds have been produced. We propose the use of responsive polymeric materials to create dynamic substrates for cell culture, which goes beyond designing only a physical static 3D scaffold. Here, we demonstrated that lactone- and lactide-based star block-copolymers (SBCs), where a liquid crystal (LC) moiety has been attached as a side-group, can be crosslinked to obtain Liquid Crystal Elastomers (LCEs) with a porous architecture using a salt-leaching method to promote cell infiltration. The obtained SmA LCE-based fully interconnected-porous foams exhibit a Young modulus of 0.23 ± 0.07 MPa and a biodegradability rate of around 20% after 15 weeks both of which are optimized to mimic native environments. We present cell culture results showing growth and proliferation of neurons on the scaffold after four weeks. This research provides a new platform to analyse LCE scaffold–cell interactions where the presence of liquid crystal moieties promotes cell alignment paving the way for a stimulated brain-like tissue.more » « less
-
{"Abstract":["Natural biological materials are formed by self-assembly processes and\n catalyze a myriad of reactions. Here, we report a programmable molecular\n assembly of designed synthetic polymers with engineered Bacillus subtilis\n spores. The bacterial spore-based materials possess modular mechanical and\n functional properties derived from the independent design and assembly of\n synthetic polymers and engineered spores . We discovered that\n phenylboronic acid (PBA) derivatives form tunable and reversible dynamic\n covalent bonds with the spore surface glycan. Spore labeling was performed\n using fluorescent PBA probes and monitored by fluorescence microscopy and\n spectroscopy. Binding affinities of PBA derivatives to spore surface\n glycan was controlled by aryl substituent effects. On the basis of this\n finding, PBA-functionalized statistical copolymers were synthesized and\n assembled with B. subtilis spores to afford macroscopic materials that\n exhibited programmable stiffness, self-healing, prolonged dry storage, and\n recyclability. These material properties could be examined using shear\n rheology, tensile testing, and NMR experiments. Integration of engineered\n spores with surface enzymes yielded reusable biocatalytic materials with\n exceptional operational simplicity and high benchtop stability. The\n reaction progress of the biocatalyses could be monitored with fluorescence\n specroscopy and absorption measurements, while spore leakage could be\n monitored by changes in solution turbidity (OD600). The use of bacterial\n spores as an active partner in dynamic covalent crosslinking sets our\n material apart from previous examples and grants control over\n biocontainment as well as the subsequent fate of the spores through\n stimuli-responsive reversal of the crosslink."],"Methods":["All experimental methods are briefly described in the README.md file, and\n fully detailed in the Supporting Information file for the paper article\n "Catalytic materials enabled by a programmable assembly of synthetic\n polymers and engineered bacterial spores"."]}more » « less
