Click cross-linking improves retention and targeting of refillable alginate depots. (August 2020)

• Record Type: Journal Article
• Authors: Moody, Christopher T.; Palvai, Sandeep; Brudno, Yevgeny
• Is Part Of: Acta biomaterialia. Volume 112(2020)
• Page Start: 112
• Page End: 121
• Publication Date: 2020-08
• Subjects: Biomaterials -- Click chemistry -- Hydrogels -- Drug targeting -- Alginate -- Biocompatibility; Az-Alg+tBCN azide-modified alginate cross-linked with tBCN -- Az-Alg+Ca2+ azide-modified alginate cross-linked with calcium sulfate -- Alg alginate -- Az azide -- BCN bicyclononyne -- COOH carboxyl group -- Ctrl-alg+Ca2+ alginate cross-linked with calcium sulfate -- Cy7 Cyanine7 -- DBCO dibenzocyclooctyne -- DMSO dimethyl sulfoxide -- DMTMM 4-(4, 6-dimethoxy-1, 3, 5-triazin-2-yl)-4-methyl-morpholinium chloride -- DS degree of substitution -- EDC N-Ethyl-N'-(3-dimethylaminopropyl)carbodiimide -- Fl-az-alg Cyanine7 fluorescence labeled azide-modified alginate. H&E, hematoxylin and eosin -- HPLC high performance liquid chromatography -- HR-MS high resolution mass spectrometry -- i.v. intravenous -- i.m. intramuscular -- LCMS liquid chromatography–mass spectrometry -- MES 2-(N-morpholino)ethanesulfonic acid -- NHS N-hydroxysuccinimide -- NMR nuclear magnetic resonance -- PAMAM polyamidoamine -- PBS phosphate buffer saline -- RO retroorbital -- ROI region of interest -- sNHS sulfo-N-hydroxysuccinimide -- SPAAC strain-promoted alkyne-azide cycloadditions -- tBCN tetrabicyclononyne -- UP UltraPure Alginate -- w/v weight per volume; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1016/j.actbio.2020.05.033
• Languages: English
• ISSNs: 1742-7061

Abstract

Abstract: Injectable alginate hydrogels have demonstrated utility in tissue engineering and drug delivery applications due in part to their mild gelation conditions, low host responses and chemical versatility. Recently, the potential of these gels has expanded with the introduction of refillable hydrogel depots - alginate gels chemically decorated with click chemistry groups to efficiently capture prodrug refills from the blood. Unfortunately, high degrees of click group substitution on alginate lead to poor viscoelastic properties and loss of ionic cross-linking. In this work, we introduce tetrabicyclononyne (tBCN) agents that covalently cross-link azide-modified alginate hydrogels for tissue engineering and drug delivery application in vivo . Adjusting cross-linker concentration allowed tuning the hydrogel mechanical properties for tissue-specific mechanical strength. The bioorthogonal and specific click reaction creates stable hydrogels with improved in vivo properties, including improved retention at injected sites. Azide-alginate hydrogels cross-linked with tBCN elicited minimal inflammation and maintained structural integrity over several months and efficiently captured therapeutics drug surrogates from the circulation. Taken together, azide-alginate hydrogels cross-linked with tBCN convey the benefits of alginate hydrogels for use in tissue engineering and drug delivery applications of refillable drug delivery depots. Statement of Significance: Ionically cross-linked, injectable alginate biomaterials hold promise in many different clinical settings. However, adding new chemical functionality to alginate can disrupt their ionic cross-linking, limiting their utility. We have developed a "click" cross-linking strategy to improve the mechanical properties and tissue function of modified alginate biomaterials and enable them to capture small molecule drugs from the blood. We show that click cross-linked materials remain in place better than ionically cross-linked materials and efficiently capture payloads from the blood. Development of click cross-linking for refillable depots represents a crucial step toward clinical application of this promising drug delivery platform. Graphical abstract: Image, graphical abstract