A modular and supramolecular approach to bioactive scaffolds for tissue engineering

The ability of highly cross-linked thermoset materials to relax stresses by network chain segment mobility above or just below T g is generally limited. We describe materials in which some of the crosslinks have been replaced by dimers of quadruple hydrogen-bonding ureidopyrimidinone (UPy) moieties, which act as reversible cross-links. Materials based on mixtures of ε-caprolactone and L-lactic acid, and containing different ratios of covalent and UPy dimer cross-links, were synthesized, and their thermal and mechanical properties were tested by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The presence of reversible cross-links results in superior relaxation of stresses even below T g , as witnessed by the creep and stress relaxation behavior. These properties bode well for potential applications, e.g., in coatings technology.

show abstract

“…Subsequent functionalization with isocyanate 3 followed reported procedures. 5 The degree of functionalization was measured by comparison of the …”

Section: Methodsmentioning

confidence: 99%

Preemptive Healing through Supramolecular Cross-Links

et al. 2009

View full text Add to dashboard Cite

show abstract

“…10,17 UPy has been used extensively by us and by others as a binding unit for supramolecular polymers. 10,[18][19][20][21] Its synthetic accessibility, and the ease with which small molecules [22][23][24] as well as telechelic polymers, 20,25,26 e.g., poly-(ethylene butylene) (PEB), 18,27 can be functionalized with UPy moieties to form supramolecular polymers with a wide range of properties, promise to enable the transformation of supramolecular polymers from a scientific curiosity to a concept with a wide range of practical applications. 5 The growth of applications of UPy-based supramolecular polymers further enhances the importance of a thorough understanding of the relation between chemical structure and mechanical properties of supramolecular polymers.…”

Section: Introductionmentioning

confidence: 99%

“…[35][36][37] UPy-based supramolecular polymeric materials prepared from telechelic polymers by functionalization with UPy synthons 18,25,27,38,39 are promising candidates for applications. The rheology of the melt state of such UPy-telechelic polymers is more complex 40,41 than for unidirectionally associated telechelic monomers or for the coordinatively cross-linked polymer networks described by Craig [42][43][44] and co-workers.…”

Section: Introductionmentioning

confidence: 99%

Unidirectional Dimerization and Stacking of Ureidopyrimidinone End Groups in Polycaprolactone Supramolecular Polymers

et al. 2007

View full text Add to dashboard Cite

The effect of stacking of end groups on the rheological behavior of supramolecular polymer melts is reported. Oscillatory shear experiments in the transition zone from the pseudo rubber plateau to the flow region of telechelic polycaprolactones (PCLs) with ureidopyrimidinone (UPy) end groups directly attached to PCL can be fitted with a single Maxwell element. This demonstrates that dimerization of the UPy groups is unidirectional and that reversible chain scission is faster than reptation. If the UPy groups are connected to the polymer via a urethane linker, a low-frequency plateau in G′ is observed. This is ascribed to the formation of a network of stacked UPy dimers, aided by urethane hydrogen bonding. Below their melting point, these stacks form long fibers in the urethane linked supramolecular poly(methyl caprolactone), which were observed with atomic force microscopy (AFM). Steric hindrance interferes with stacking, since the plateau in G′ is lower in a urethane linked polymer with bulky adamantyl-UPy end groups.

show abstract

“…Such approaches to generate fibers are limited by high energy input, laborious procedures, and intensive use of organic solvents. Supramolecular pathways enable the formation of filamentous soft materials that are showing promise in biomedical applications (4)(5)(6), such as cell culture (7)(8)(9) and tissue engineering (10). However, such materials are constrained by the length scale (submicrometer level) (11)(12)(13), energy intake during production (9), and complex design of assembly units (14).…”

mentioning

confidence: 99%

Bioinspired supramolecular fibers drawn from a multiphase self-assembled hydrogel

Shah

Liu

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

125

114

View full text Add to dashboard Cite

Inspired by biological systems, we report a supramolecular polymer-colloidal hydrogel (SPCH) composed of 98 wt % water that can be readily drawn into uniform (∼6-µm thick) "supramolecular fibers" at room temperature. Functionalized polymer-grafted silica nanoparticles, a semicrystalline hydroxyethyl cellulose derivative, and cucurbit[8]uril undergo aqueous self-assembly at multiple length scales to form the SPCH facilitated by host-guest interactions at the molecular level and nanofibril formation at colloidal-length scale. The fibers exhibit a unique combination of stiffness and high damping capacity (60-70%), the latter exceeding that of even biological silks and cellulose-based viscose rayon. The remarkable damping performance of the hierarchically structured fibers is proposed to arise from the complex combination and interactions of "hard" and "soft" phases within the SPCH and its constituents. SPCH represents a class of hybrid supramolecular composites, opening a window into fiber technology through low-energy manufacturing. supramolecular fiber | hydrogel | self-assembly | damping | spider silk I n nature, spiders spin silk fibers with superb properties at ambient temperatures and pressures (1, 2). We have yet to mimic such an elegant process. Conventionally, synthetic fibers are manufactured through a variety of spinning techniques, including wet, dry, gel, and electrospinning (3). Such approaches to generate fibers are limited by high energy input, laborious procedures, and intensive use of organic solvents. Supramolecular pathways enable the formation of filamentous soft materials that are showing promise in biomedical applications (4-6), such as cell culture (7-9) and tissue engineering (10). However, such materials are constrained by the length scale (submicrometer level) (11-13), energy intake during production (9), and complex design of assembly units (14).Here, we report drawing supramolecular fibers of arbitrary length from a dynamic supramolecular polymer-colloidal hydrogel (SPCH) at room temperature (Movie S1). The components consist of methyl viologen (MV)-functionalized polymer-grafted silica nanoparticles (P1), a semicrystalline polymer in the form of a hydroxyethyl cellulose derivative (H1), and cucurbit[8]uril (CB[8]) as illustrated in Fig. 1. The macrocycle CB[8] is capable of simultaneously encapsulating two guests within its cavity, forming a stable yet dynamic ternary complex, and has been exploited as a supramolecular "handcuff" to physical cross-link functional polymers (15-18). Introducing shape-persistent nanoparticles into the supramolecular hydrogel system allows for modification of the local gel structures at the colloidal-length scale, resulting in assemblies with unique emergent properties (19). The hierarchical nature of the SPCH is presented, where the hydrogel is composed of nanoscale fibrillar structures. The self-assembled SPCH composite exhibits great elasticity at a remarkably high water content (98%), showing a low-energy manufacturing process for fibers from natural, ...

show abstract

A modular and supramolecular approach to bioactive scaffolds for tissue engineering

Cited by 430 publications

References 28 publications

Preemptive Healing through Supramolecular Cross-Links

Preemptive Healing through Supramolecular Cross-Links

Unidirectional Dimerization and Stacking of Ureidopyrimidinone End Groups in Polycaprolactone Supramolecular Polymers

Bioinspired supramolecular fibers drawn from a multiphase self-assembled hydrogel

Contact Info

Product

Resources

About