Smart hybrid materials by conjugation of responsive polymers to biomacromolecules

Abstract

The chemical structure and function of biomacromolecules has evolved to fill many essential roles in biological systems. More specifically, proteins, peptides, nucleic acids and polysaccharides serve as vital structural components, and mediate chemical transformations and energy/information storage processes required to sustain life. In many cases, the properties and applications of biological macromolecules can be further expanded by attaching synthetic macromolecules. The modification of biomacromolecules by attaching a polymer that changes its properties in response to environmental variations, thus affecting the properties of the biomacromolecule, has led to the emergence of a new family of polymeric biomaterials. Here, we summarize techniques for conjugating responsive polymers to biomacromolecules and highlight applications of these bioconjugates reported so far. In doing so, we aim to show how advances in synthetic tools could lead to rapid expansion in the variety and uses of responsive bioconjugates.

Transiently malleable multi-healable hydrogel nanocomposites based on responsive boronic acid copolymers

“…97,98 This is facilitated by the "hide-and-reveal" type of interaction that is driven by the well-known reversible coil-toglobule transition of NIPAAm copolymers in aqueous solutions. 65,89,99 To clarify the diol-boronate binding specificity, a PNIPAAm homopolymer was synthesised and mixed with PVA; as expected, no gel formation was observed. Another control experiment involved the immersion of a P1-PVA gel in a 2.5% (w/v) concentrated glucose solution where rapid degradation was observed (Fig.…”

Self-assembly and disassembly of stimuli responsive tadpole-like single chain nanoparticles using a switchable hydrophilic/hydrophobic boronic acid cross-linker

“…SCNPs can not only mimic the delicate controlled folding process of proteins with controlled size and morphology, [31][32][33] but can also self-assemble into more complexed 3D structures. 34 Furthermore stimuli-responsive polymeric nanoparticles, also called "smart" or "intelligent" nanoparticles that are capable of conformational and chemical changes by adapting the external stimuli 35,36 have increasingly attracted interest due to their diverse range of applications in delivery and release of drugs, 37,38 diagnostics, 39 sensors. 40 Dynamic covalent chemistry is a very suitable candidate for building intelligent materials which can be responsive to the environmental changes, such as pH or input stimuli.…”

Comparison of metal free polymer–dye conjugation strategies in protic solvents

“…17,18 All these conjugation strategies have been proven successful in a variety of examples. 6 Nonetheless, each of these methods also has drawbacks and may or may not be compliant with the needs of a specific research approach.…”

“…4,19 In this instance, the ring-strain promoted azide-alkyne reaction (SPAAC) becomes of interest as it is additive-free and reported to occur almost instantaneously. 19,20 The ring strain is present in the alkyne, which is integrated in a [6,1,0] bicyclic nonyne ( Figure 1). Due to its high ring tension, however, this moiety can also react with other functional groups, thus resulting in lack of a stability and selectivity, ultimately limiting the scope of SPAAC.…”