PMID- 30102855 OWN - NLM STAT- MEDLINE DCOM- 20190902 LR - 20230928 IS - 1526-4602 (Electronic) IS - 1525-7797 (Print) IS - 1525-7797 (Linking) VI - 19 IP - 9 DP - 2018 Sep 10 TI - Native Chemical Ligation for Cross-Linking of Flower-Like Micelles. PG - 3766-3775 LID - 10.1021/acs.biomac.8b00908 [doi] AB - In this study, native chemical ligation (NCL) was used as a selective cross-linking method to form core-cross-linked thermosensitive polymeric micelles for drug delivery applications. To this end, two complementary ABA triblock copolymers having polyethylene glycol (PEG) as midblock were synthesized by atom transfer radical polymerization (ATRP). The thermosensitive poly isopropylacrylamide (PNIPAM) outer blocks of the polymers were copolymerized with either N-(2-hydroxypropyl)methacrylamide-cysteine (HPMA-Cys), P(NIPAM- co-HPMA-Cys)-PEG-P(NIPAM- co-HPMA-Cys) (PNC) or N-(2-hydroxypropyl)methacrylamide-ethylthioglycolate succinic acid (HPMA-ETSA), P(NIPAM- co-HPMA-ETSA)-PEG-P(NIPAM- co-HPMA-ETSA) (PNE). Mixing of these polymers in aqueous solution followed by heating to 50 degrees C resulted in the formation of thermosensitive flower-like micelles. Subsequently, native chemical ligation in the core of micelles resulted in stabilization of the micelles with a Z-average of 65 nm at body temperature. Decreasing the temperature to 10 degrees C only affected the size of the micelles (increased to 90 nm) but hardly affected the polydispersity index (PDI) and aggregation number ( N(agg)) confirming covalent stabilization of the micelles by NCL. CryoTEM images showed micelles with an uniform spherical shape and dark patches close to the corona of micelles were observed in the tomographic view. The dark patches represent more dense areas in the micelles which coincide with the higher content of HPMA-Cys/ETSA close to the PEG chain revealed by the polymerization kinetics study. Notably, this cross-linking method provides the possibility for conjugation of functional molecules either by using the thiol moieties still present after NCL or by simply adjusting the molar ratio between the polymers (resulting in excess cysteine or thioester moieties) during micelle formation. Furthermore, in vitro cell experiments demonstrated that fluorescently labeled micelles were successfully taken up by HeLa cells while cell viability remained high even at high micelle concentrations. These results demonstrate the potential of these micelles for drug delivery applications. FAU - Najafi, Marzieh AU - Najafi M AD - Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science , Utrecht University , P.O. Box 80082, 3508 TB Utrecht , The Netherlands. FAU - Kordalivand, Neda AU - Kordalivand N AD - Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science , Utrecht University , P.O. Box 80082, 3508 TB Utrecht , The Netherlands. FAU - Moradi, Mohammad-Amin AU - Moradi MA AUID- ORCID: 0000-0003-3754-9200 AD - Laboratory of Materials and Interface Chemistry and Centre for Multiscale Electron Microscopy Department of Chemical Engineering and Chemistry , Eindhoven University of Technology , Eindhoven , 5600 MB , The Netherlands. AD - Institute for Complex Molecular Systems , Eindhoven University of Technology , Eindhoven , 5600 MB , The Netherlands. FAU - van den Dikkenberg, Joep AU - van den Dikkenberg J AD - Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science , Utrecht University , P.O. Box 80082, 3508 TB Utrecht , The Netherlands. FAU - Fokkink, Remco AU - Fokkink R AD - Physical Chemistry and Soft Matter , Wageningen University and Research , Stippeneng 4 , 6708 WE Wageningen , The Netherlands. FAU - Friedrich, Heiner AU - Friedrich H AUID- ORCID: 0000-0003-4582-0064 AD - Laboratory of Materials and Interface Chemistry and Centre for Multiscale Electron Microscopy Department of Chemical Engineering and Chemistry , Eindhoven University of Technology , Eindhoven , 5600 MB , The Netherlands. AD - Institute for Complex Molecular Systems , Eindhoven University of Technology , Eindhoven , 5600 MB , The Netherlands. FAU - Sommerdijk, Nico A J M AU - Sommerdijk NAJM AUID- ORCID: 0000-0002-8956-195X AD - Laboratory of Materials and Interface Chemistry and Centre for Multiscale Electron Microscopy Department of Chemical Engineering and Chemistry , Eindhoven University of Technology , Eindhoven , 5600 MB , The Netherlands. AD - Institute for Complex Molecular Systems , Eindhoven University of Technology , Eindhoven , 5600 MB , The Netherlands. FAU - Hembury, Mathew AU - Hembury M AUID- ORCID: 0000-0002-7949-0027 AD - Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science , Utrecht University , P.O. Box 80082, 3508 TB Utrecht , The Netherlands. FAU - Vermonden, Tina AU - Vermonden T AUID- ORCID: 0000-0002-6047-5900 AD - Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science , Utrecht University , P.O. Box 80082, 3508 TB Utrecht , The Netherlands. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20180824 PL - United States TA - Biomacromolecules JT - Biomacromolecules JID - 100892849 RN - 0 (Acrylic Resins) RN - 0 (Cross-Linking Reagents) RN - 0 (Drug Carriers) RN - 0 (Methacrylates) RN - 0 (Micelles) RN - 0 (Protein Corona) RN - 0 (Thioglycolates) RN - 25189-55-3 (poly-N-isopropylacrylamide) RN - 3WJQ0SDW1A (Polyethylene Glycols) RN - UKW89XAX2X (hydroxypropyl methacrylate) SB - IM MH - Acrylic Resins/chemistry MH - Cross-Linking Reagents/*chemistry MH - Drug Carriers/*chemical synthesis MH - HeLa Cells MH - Humans MH - Methacrylates/chemistry MH - *Micelles MH - Polyethylene Glycols/chemistry MH - Protein Corona/chemistry MH - Temperature MH - Thioglycolates/chemistry PMC - PMC6143283 COIS- The authors declare no competing financial interest. EDAT- 2018/08/14 06:00 MHDA- 2019/09/03 06:00 PMCR- 2018/09/18 CRDT- 2018/08/14 06:00 PHST- 2018/08/14 06:00 [pubmed] PHST- 2019/09/03 06:00 [medline] PHST- 2018/08/14 06:00 [entrez] PHST- 2018/09/18 00:00 [pmc-release] AID - 10.1021/acs.biomac.8b00908 [doi] PST - ppublish SO - Biomacromolecules. 2018 Sep 10;19(9):3766-3775. doi: 10.1021/acs.biomac.8b00908. Epub 2018 Aug 24.