Optothermally Reversible Carbon Nanotube–DNA Supramolecular Hybrid Hydrogels

Abstract

Supramolecular hydrogels (SMHs) are three-dimensional constructs wherein the majority of the volume is occupied by water. Since the bonding forces between the components of SMHs are noncovalent, SMH properties are often tunable, stimuli-responsive, and reversible, which enables applications including triggered drug release, sensing, and tissue engineering. Meanwhile, single-walled carbon nanotubes (SWCNTs) possess superlative electrical and thermal conductivities, high mechanical strength, and strong optical absorption at near-infrared wavelengths that have the potential to add unique functionality to SMHs. However, SWCNT-based SMHs have thus far not realized the potential of the optical properties of SWCNTs to enable reversible response to near-infrared irradiation. Here, we present a novel SMH architecture comprised solely of DNA and SWCNTs, wherein noncovalent interactions provide structural integrity without compromising the intrinsic properties of SWCNTs. The mechanical properties of these SMHs are readily tuned by varying the relative concentrations of DNA and SWCNTs, which varies the cross-linking density as shown by molecular dynamics simulations. Moreover, the SMH gelation transition is fully reversible and can be triggered by a change in temperature or near-infrared irradiation. This work explores a new regime for SMHs with potential utility for a range of applications including sensors, actuators, responsive substrates, and 3D printing.

Smart Nucleic Acid Hydrogels with High Stimuli-Responsiveness in Biomedical Fields

“…Since then, the era of co-synthesis of NAHs by polymers and FNAs has been entered. In recent years, polymers and nanomaterials have started to be used to prepare NAHs with nucleic acids, including, but not limited to, graphene oxide graphene oxide (GO) [15][16][17], carbon dots (CD) [18][19][20], carbon nanotubes [21], quantum dots [22], magnetic beads [23], polyacrylamide (PAM) [24][25][26][27][28][29][30], poly-N-isopropylacrylamide (p-NIPAM) [31,32], polyethylene glycol (PEG) [33][34][35][36], and poly-L-lysine (PLL) [37]. The use of these materials helps to improve the performance of hydrogels, reduce nucleic acid use, and speed up the synthesis of hydrogels.…”

Smart and Functionalized Development of Nucleic Acid‐Based Hydrogels: Assembly Strategies, Recent Advances, and Challenges

“…Either the cross‐linking between the DNA building blocks and nanomaterials is formed via physical interaction, or the nanomaterials are encapsulated in the DNA hydrogel networks. The nanomaterials applied for the development of hybrid NAHs cover a variety of categories, including carbon‐based nanomaterials, such as GO, [ 76 , 77 ] carbon‐nanotubes, [ 78 , 79 ] carbon dots, [ 80 , 81 , 82 ] quantum dots, [ 83 ] magnetic beads, [ 84 , 85 , 86 , 87 , 88 ] liposome, [ 57 ] gold nanoparticles (AuNPs), [ 68 , 75 , 89 , 90 , 91 ] silica nanoparticles, [ 54 , 92 ] Laponite nanoparticles, [ 93 , 94 , 95 ] and photonic crystal (PC). [ 96 ] The interaction between DNA and nanomaterials reveals their multiple functional features, further enhancing the corresponding applications.…”

“…Macrocyclic host–guest interactions, as noncovalent cross‐linking forces, have been widely used to synthesize multifarious biomolecule‐based supramolecular hydrogels but had not been utilized to produce NAHs until recently. [ 78 , 98 , 130 ] Given their excellent dynamic nature, the host–guest interactions, provided by low molecular weight gelators or physically cross‐linked polymers, drive the self‐assembly of DNA strands with each other, or DNA molecules with other polymers, to form DNA‐based supramolecular hydrogels with outstanding chemical and physical properties, such as shape‐memory, self‐healing, and swelling. [ 98 , 131 , 132 , 133 , 134 ] In supramolecular hydrogels, the multiple water‐soluble macrocyclic hosts have been introduced into the building blocks or scaffolds, such as cyclodextrins (CD), cucurbit[n]urils (CB[n]), calix[n]arenes, and pillar[n]arenes (PA[n]s).…”

Putting DNA to Work as Generic Polymeric Materials

“…The Das group used DNA to decorate carbon dots and then created DNA hybrid hydrogels through the crosslinking of i‐motif structures [49] . Furthermore, the Hersam group also fabricated single‐walled carbon nanotube (SWCNT) and DNA hybrid hydrogels by using DNA linkers to crosslink DNA‐modified SWCNTs [50] …”

“…[49] Furthermore,t he Hersam group also fabricated single-walled carbon nanotube (SWCNT) and DNAh ybrid hydrogels by using DNAl inkers to crosslink DNA-modified SWCNTs. [50]…”