{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,7]],"date-time":"2026-03-07T19:40:08Z","timestamp":1772912408268,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2021,7,27]],"date-time":"2021-07-27T00:00:00Z","timestamp":1627344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003593","name":"Conselho Nacional de Desenvolvimento Cient\u00edfico e Tecnol\u00f3gico","doi-asserted-by":"publisher","award":["protocol 0008678964988973"],"award-info":[{"award-number":["protocol 0008678964988973"]}],"id":[{"id":"10.13039\/501100003593","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002322","name":"Coordena\u00e7\u00e3o de Aperfei\u00e7oamento de Pessoal de N\u00edvel Superior","doi-asserted-by":"publisher","award":["Finance Code 001"],"award-info":[{"award-number":["Finance Code 001"]}],"id":[{"id":"10.13039\/501100002322","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/QUI\/00313\/2020"],"award-info":[{"award-number":["UID\/QUI\/00313\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Gelatin (GE), amino-functionalized polyphenolic tannin derivative (TN), and graphene oxide (GO) were associated to yield thermo- and pH-responsive hydrogels for the first time. Durable hydrogel assemblies for drug delivery purposes were developed using the photosensitizer methylene blue (MB) as a drug model. The cooling GE\/TN blends provide brittle physical assemblies. To overcome this disadvantage, different GO contents (between 0.31% and 1.02% wt\/wt) were added to the GE\/TN blend at 89.7\/10.3 wt\/wt. FTIR and RAMAN spectroscopy analyses characterized the materials, indicating GO presence in the hydrogels. Incorporation studies revealed a total MB (0.50 mg\/mL) incorporation into the GE\/TN-GO hydrogel matrices. Additionally, the proposed systems present a mechanical behavior similar to gel. The GO presence in the hydrogel matrices increased the elastic modulus from 516 to 1650 Pa. SEM revealed that hydrogels containing MB present higher porosity with interconnected pores. Dissolution and swelling degree studies revealed less stability of the GE\/TN-GO-MB hydrogels in SGF medium (pH 1.2) than SIF (pH 6.8). The degradation increased in SIF with the GO content, making the polymeric matrices more hydrophilic. MB release studies revealed a process controlled by Fickian diffusion. Our results point out the pH-responsible behavior of mechanically reinforced GE\/TN-GO-MB hydrogels for drug delivery systems purposes.<\/jats:p>","DOI":"10.3390\/molecules26154529","type":"journal-article","created":{"date-parts":[[2021,7,27]],"date-time":"2021-07-27T12:18:31Z","timestamp":1627388311000},"page":"4529","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Thermo- and pH-Responsive Gelatin\/Polyphenolic Tannin\/Graphene Oxide Hydrogels for Efficient Methylene Blue Delivery"],"prefix":"10.3390","volume":"26","author":[{"given":"Ariel C.","family":"de Oliveira","sequence":"first","affiliation":[{"name":"Group of Polymeric Materials and Composites, Department of Chemistry, State University of Maring\u00e1 (UEM), Maring\u00e1 87020-900, PR, Brazil"}]},{"given":"Paulo R.","family":"Souza","sequence":"additional","affiliation":[{"name":"Group of Polymeric Materials and Composites, Department of Chemistry, State University of Maring\u00e1 (UEM), Maring\u00e1 87020-900, PR, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9050-5760","authenticated-orcid":false,"given":"Bruno H.","family":"Vilsinski","sequence":"additional","affiliation":[{"name":"Group of Polymeric Materials and Composites, Department of Chemistry, State University of Maring\u00e1 (UEM), Maring\u00e1 87020-900, PR, Brazil"},{"name":"Chemistry Department, Institute of Exact Sciences, Federal University of Juiz de Fora, Juiz de Fora 36036-900, MG, Brazil"}]},{"given":"Manuel E. G.","family":"Winkler","sequence":"additional","affiliation":[{"name":"Group of Polymeric Materials and Composites, Department of Chemistry, State University of Maring\u00e1 (UEM), Maring\u00e1 87020-900, PR, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4838-5742","authenticated-orcid":false,"given":"Marcos L.","family":"Bruschi","sequence":"additional","affiliation":[{"name":"Laboratory of Research and Development of Drug Delivery Systems, Department of Pharmacy, State Univesity of Maring\u00e1 (UEM), 5970 Colombo Avenue, Maring\u00e1 87020-900, PR, Brazil"}]},{"given":"Eduardo","family":"Radovanovic","sequence":"additional","affiliation":[{"name":"Department of Chemistry, State University of Maringa, Maring\u00e1 87020-900, PR, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6685-1519","authenticated-orcid":false,"given":"Edvani C.","family":"Muniz","sequence":"additional","affiliation":[{"name":"Group of Polymeric Materials and Composites, Department of Chemistry, State University of Maring\u00e1 (UEM), Maring\u00e1 87020-900, PR, Brazil"},{"name":"Department of Chemistry, Federal University of Piaui, Teresina 64049-550, PI, Brazil"}]},{"given":"Wilker","family":"Caetano","sequence":"additional","affiliation":[{"name":"N\u00facleo de Pesquisas em Sistemas Fotodin\u00e2micos, Chemistry Department, State University of Maring\u00e1, Maring\u00e1 87020-900, PR, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4612-7686","authenticated-orcid":false,"given":"Artur J. M.","family":"Valente","sequence":"additional","affiliation":[{"name":"Department of Chemistry, CQC, University of Coimbra, 3004-535 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1002-3436","authenticated-orcid":false,"given":"Alessandro F.","family":"Martins","sequence":"additional","affiliation":[{"name":"Group of Polymeric Materials and Composites, Department of Chemistry, State University of Maring\u00e1 (UEM), Maring\u00e1 87020-900, PR, Brazil"},{"name":"Laboratory of Materials, Macromolecules and Composites, Federal University of Technology\u2014Paran\u00e1 (UTFPR), Apucarana 86812-460, PR, Brazil"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Souza, P.R., de Oliveira, A.C., Vilsinski, B.H., Kipper, M.J., and Martins, A.F. (2021). Polysaccharide-Based Materials Created by Physical Processes: From Preparation to Biomedical Applications. 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