title: Hierarchical Organization of Organic Dyes and Protein Cages into Photoactive Crystals.
abstract: Phthalocyanines (Pc) are non-natural organic dyes with wide and deep impact in materials science, based on their intense absorption at the near-infrared (NIR), long-lived fluorescence and high singlet oxygen ((1)O2) quantum yields. However, Pcs tend to stack in buffer solutions, losing their ability to generate singlet oxygen, which limits their scope of application. Furthermore, Pcs are challenging to organize in crystalline structures. Protein cages, on the other hand, are very promising biological building blocks that can be used to organize different materials into crystalline nanostructures. Here, we combine both kinds of components into photoactive biohybrid crystals. Toward this end, a hierarchical organization process has been designed in which (a) a supramolecular complex is formed between octacationic zinc Pc (1) and a tetraanionic pyrene (2) derivatives, driven by electrostatic and π-π interactions, and (b) the resulting tetracationic complex acts as a molecular glue that binds to the outer surface anionic patches of the apoferritin (aFt) protein cage, inducing cocrystallization. The obtained ternary face-centered cubic (fcc) packed cocrystals, with diameters up to 100 μm, retain the optical properties of the pristine dye molecules, such as fluorescence at 695 nm and efficient light-induced (1)O2 production. Considering that (1)O2 is utilized in important technologies such as photodynamic therapy (PDT), water treatments, diagnostic arrays and as an oxidant in organic synthesis, our results demonstrate a powerful methodology to create functional biohybrid systems with unprecedented long-range order. This approach should greatly aid the development of nanotechnology and biomedicine.
authors.affiliation: Biohybrid Materials, Department of Biotechnology and Chemical Technology, Aalto University , FI-00076 Aalto, Finland.
authors.forename: Joona
authors.initials: J
authors.lastname: Mikkilä
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid/IMDEA Nanociencia (TT) , 28049 Madrid, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Anaya-Plaza
authors.affiliation: Biohybrid Materials, Department of Biotechnology and Chemical Technology, Aalto University , FI-00076 Aalto, Finland.
authors.forename: Ville
authors.initials: V
authors.lastname: Liljeström
authors.affiliation: Department of Structure of Macromolecules, Centro Nacional de Biotecnología/CSIC, Cantoblanco , 28049 Madrid, Spain.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Caston
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid/IMDEA Nanociencia (TT) , 28049 Madrid, Spain.
authors.forename: Tomas
authors.initials: T
authors.lastname: Torres
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid/IMDEA Nanociencia (TT) , 28049 Madrid, Spain.
authors.forename: Andrés de la
authors.initials: Ade L
authors.lastname: Escosura
authors.affiliation: Biohybrid Materials, Department of Biotechnology and Chemical Technology, Aalto University , FI-00076 Aalto, Finland.
authors.forename: Mauri A
authors.initials: MA
authors.lastname: Kostiainen
mesh_terms: D001052:Apoferritins / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D003460:Crystallization; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D009942:Organometallic Compounds / Q000737:chemistry*; D055668:Photochemical Processes; D011721:Pyrenes / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry; D017967:Zinc Compounds
chemical_list: D004396:Coloring Agents; D007211:Indoles; D054833:Isoindoles; D009942:Organometallic Compounds; D011721:Pyrenes; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D026082:Singlet Oxygen; D001052:Apoferritins; C041343:1,3,6,8-pyrene tetrasulfonate
keywords: crystal; ferritin; phthalocyanine; protein cage; self-assembly; singlet oxygen