ConspectusConstitutional dynamic chemistry (CDC) features the use of reversible
linkages at both molecular and supramolecular levels, including reversible
covalent bonds (dynamic covalent chemistry, DCC) and noncovalent interactions
(dynamic noncovalent chemistry, DNCC). Due to its inherent reversibility
and stimuli-responsiveness, CDC has been widely utilized as a powerful
tool for the screening of bioactive compounds, the exploitation of
receptors or substrates driven by molecular recognition, and the fabrication
of constitutionally dynamic materials. Implementation of CDC in biopolymer
science leads to the generation of constitutionally dynamic analogues
of biopolymers, biodynamers, at the molecular level (molecular biodynamers)
through DCC or at the supramolecular level (supramolecular biodynamers)
via DNCC. Therefore, biodynamers are prepared by reversible covalent
polymerization or noncovalent polyassociation of biorelevant monomers.In particular, molecular biodynamers, biodynamers of the covalent
type whose monomeric units are connected by reversible covalent bonds,
are generated by reversible polymerization of bio-based monomers and
can be seen as a combination of biopolymers with DCC. Owing to the
reversible covalent bonds used in DCC, molecular biodynamers can undergo
continuous and spontaneous constitutional modifications via incorporation/decorporation
and exchange of biorelevant monomers in response to internal or external
stimuli. As a result, they behave as adaptive materials with novel
properties, such as self-healing, stimuli-responsiveness, and tunable
mechanical and optical character. More specifically, molecular biodynamers
combine the biorelevant characters (e.g., biocompatibility, biodegradability,
biofunctionality) of bioactive monomers with the dynamic features
of reversible covalent bonds (e.g., changeable, tunable, controllable,
self-healing, and stimuli-responsive capacities), to realize synergistic
properties in one system. In addition, molecular biodynamers are commonly
produced in aqueous media under mild or even physiological conditions
to suit their biorelated applications.In contrast to static
biopolymers emphasizing structural stability
and unity by using irreversible covalent bonds, molecular biodynamers
are seeking relative structural adaptability and diversity through
the formation of reversible covalent bonds. Based on these considerations,
molecular biodynamers are capable of reorganizing their monomers,
generating, identifying, and amplifying the fittest structures in
response to environmental factors. Hence, molecular biodynamers have
received considerable research attention over the past decades. Accordingly,
the construction of molecular biodynamers through equilibrium polymerization
of nucleobase-, carbohydrate- or amino-acid-based monomers can lead
to the fabrication of dynamic analogues of nucleic acids (DyNAs),
polysaccharides (glycodynamers), or proteins (dynamic proteoids),
respectively. In this Account, we summarize recent advances in developing
different types of...