TY - JOUR
T1 - Self-Repair of Structure and Bioactivity in a Supramolecular Nanostructure
AU - Chen, Charlotte H.
AU - Palmer, Liam C.
AU - Stupp, Samuel I.
N1 - Funding Information:
Synthesis of PAs and study of the self-assembly landscapes were supported by the Center for Bio-Inspired Energy Sciences (CBES), an Energy Frontiers Research Center (EFRC) funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under award number DE-SC0000989. Biological studies were funded by the NIH/NIDCR (Grant No. 2R01DE015920-11) and the Northwestern University Center for Regenerative Nanomedicine Catalyst Award. C.H.C. has received support from a National Defense Science and Engineering Graduate Fellowship and a NIH T32 HD07418. The following research facilities at Northwestern University were used in this work: Peptide Synthesis and Analytical BioNano Technology Equipment Cores of the Simpson Querrey Institute (U.S. Army Research Office, U.S. Army Medical Research and Materiel Command, Northwestern University, Soft and Hybrid Nanotechnology Experimental [SHyNE] Resource [NSF NNCI-1542205]), Optical Microscopy and Metallography Facility (MRSEC Program [DMR-1121262]), Keck Biophysics Facility (NCI CCSG P30 CA060553 grant awarded to the Robert H. Lurie Comprehensive Cancer Center), Biological Imaging Facility (North-western University Office for Research), and EPIC Facility at the NUANCE Center (SHyNE Resource [NSF NNCI-1542205], MRSEC Program [NSF DMR-1121262]; International Institute for Nanotechnology [IIN], Keck Foundation, the State of Illinois, through the IIN), Center for Advanced Microscopy (NCI CCSG P30 CA060553 awarded to the Robert H Lurie Comprehensive Cancer Center). This work also made use of the DuPont-Northwestern-Dow Collaborative Access Team (Northwestern University, E.I. DuPont de Nemours & Co., and The Dow Chemical Company) located at Sector 5 of the Advanced Photon Source (U.S. Department of Energy [DOE] Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357). We are grateful to Theint Aung (Keck Biophysics Facility) for performing all NTA experiments and Charlene Wilke (Biological Imaging Facility) for preparing thin sections for TEM imaging.
PY - 2018/11/14
Y1 - 2018/11/14
N2 - Supramolecular nanostructures formed through self-assembly can have energy landscapes, which determine their structures and functions depending on the pathways selected for their synthesis and processing and on the conditions they are exposed to after their initial formation. We report here on the structural damage that occurs in supramolecular peptide amphiphile nanostructures, during freezing in aqueous media, and the self-repair pathways that restore their functions. We found that freezing converts long supramolecular nanofibers into shorter ones, compromising their ability to support cell adhesion, but a single heating and cooling cycle reverses the damage and rescues their bioactivity. Thermal energy in this cycle enables noncovalent interactions to reconfigure the nanostructures into the thermodynamically preferred long nanofibers, a repair process that is impeded by kinetic traps. In addition, we found that nanofibers disrupted during freeze-drying also exhibit the ability to undergo thermal self-repair and recovery of their bioactivity, despite the extra disruption caused by the dehydration step. Following both freezing and freeze-drying, which shorten the 1D nanostructures, their self-repair capacity through thermally driven elongation is inhibited by kinetically trapped states, which contain highly stable noncovalent interactions that are difficult to rearrange. These states decrease the extent of thermal nanostructure repair, an observation we hypothesize applies to supramolecular systems in general and is mechanistically linked to suppressed molecular exchange dynamics.
AB - Supramolecular nanostructures formed through self-assembly can have energy landscapes, which determine their structures and functions depending on the pathways selected for their synthesis and processing and on the conditions they are exposed to after their initial formation. We report here on the structural damage that occurs in supramolecular peptide amphiphile nanostructures, during freezing in aqueous media, and the self-repair pathways that restore their functions. We found that freezing converts long supramolecular nanofibers into shorter ones, compromising their ability to support cell adhesion, but a single heating and cooling cycle reverses the damage and rescues their bioactivity. Thermal energy in this cycle enables noncovalent interactions to reconfigure the nanostructures into the thermodynamically preferred long nanofibers, a repair process that is impeded by kinetic traps. In addition, we found that nanofibers disrupted during freeze-drying also exhibit the ability to undergo thermal self-repair and recovery of their bioactivity, despite the extra disruption caused by the dehydration step. Following both freezing and freeze-drying, which shorten the 1D nanostructures, their self-repair capacity through thermally driven elongation is inhibited by kinetically trapped states, which contain highly stable noncovalent interactions that are difficult to rearrange. These states decrease the extent of thermal nanostructure repair, an observation we hypothesize applies to supramolecular systems in general and is mechanistically linked to suppressed molecular exchange dynamics.
KW - Supramolecular nanostructures
KW - biomaterials
KW - cell-nanostructure interactions
KW - regenerative medicine
KW - self-assembly
KW - self-repair
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U2 - 10.1021/acs.nanolett.8b02709
DO - 10.1021/acs.nanolett.8b02709
M3 - Article
C2 - 30379077
AN - SCOPUS:85056281121
VL - 18
SP - 6832
EP - 6841
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 11
ER -