A Versatile Approach for the Assembly of Highly Tunable Biocatalytic Thin Films

Abstract

Nevertheless, the utilization of biomolecules, i.e., proteins, to impart functionality to inorganic and/or organic materials and afford highly efficient functional devices presents a number of challenges in the research of functional biomaterials. [4][5][6] The main limitations predominantly arise from intermolecular aggregation, surfaceinduced denaturation, steric hindrance of active sites, and lack of dynamical freedom imposed by solid state. [7][8][9] The deposition of continuous protein thin films seems to be a good strategy that fulfill those needs. [10,11] With particular emphasis on biocatalytic coatings, the fabrication method should guarantee high enzyme loads, low substrate/product flow transport limitations, and improve the lifetime and stability of the biomolecule. [12] Currently, reported methods for the fabrication of functional biofilms are based on the utilization of a relatively limited range of naturally self-assembling proteins, layer-by-layer deposition approaches, and the adsorption of the proteins to amphiphilic copolymers. [13][14][15][16][17] However, these approaches usually require of the covalent crosslinking of the components in order to avoid the disaggregation of the film in water and at broad range of pH. [18] Yet, the uncontrolled covalent crosslinking might be especially damaging in the formation of functional protein films. The protein's amino acids can be altered and severe substrate diffusion issues might be caused within the film, resulting in impaired biomaterials. [19] Therefore, an alternative sequence-independent methodology that allows the fabrication of functional protein films would vastly expand the toolkit for creating biomaterials.In this regard, the bioinspired self-assembly of hierarchically structured peptide or protein films is an attractive approach. [20][21][22][23] In nature, the metal-driven crosslinking of specific peptidic building blocks leads to complex hierarchical structures across many lengths, as it happens in mussel byssus or worm jaws. [24][25][26] Furthermore, metal-directed protein selfassembly (MDPSA) methodology is inspired by the affinity of distinct residue side chains such as histidines, cysteines, lysines, and asparagines toward metallic cations (mainly Ni, Cu, Co, and Zn). MDPSA allocates such key residues on the surface of the protein as anchoring points. [27][28][29] Hence, metal ions are used as inorganic bridges that not only guide the assembly of the proteins into hierarchical architectures, but also might The deposition of protein thin films on (in)organic surfaces is a key approach to incorporate new functionalities into these materials for a broad number of applications. However, most of the current methods used for the controlled assembly of such biomolecules and eventual film formation are limiting since entail either the chemical modification of the proteins, which leads sometimes to impaired materials, or the sequential layer-by-layer deposition of charged macromolecules. In this work, a facile bioinspired method for the versati...

Polyion Complex-Templated Synthesis of Cross-Linked Single-Enzyme Nanoparticles

“…In order to minimize the risk of enzyme deactivation during the synthesis of the SEN, several groups have shown the assembly of SENs via noncovalent means. ,− In one recent example, Delaittre and co-workers showed that in the presence of certain sugars, acrylamide and bisacryalmide bind strongly enough to the surface of unmodified enzymes to drive the formation of the hydrogel shell around it when a free-radical polymerization is initiated in solution . SENs prepared by this direct in situ polymerization showed negligible initial activity loss and high enzymatic stability against temperature and a wide range of pHs.…”

Tunable Polymeric Scaffolds for Enzyme Immobilization

“…In particular, polymer-enzyme films-based biosensors have been widely studied as alternative to the traditional chemical methodologies. The assembly of enzyme-polymer hybrids in film fashion can be performed by simple deposition or drop casting ( Rodriguez-Abetxuko et al, 2019b ; Sánchez-deAlcázar et al, 2019 ), by spin-coating ( Chen B. et al, 2008 ), by layer-by-layer approaches ( Scodeller et al, 2014 ; Zhang et al, 2019b ), by electrospinning ( Henke et al, 2020 ), by dip-coating ( Marquitan et al, 2020 ) or by Langmuir–Blodget technique ( Qian et al, 2002 ). Smaller enzyme-polymer hybrids, e.g., MOFs, particles or SENs, ( Dong et al, 2018 ; Liu et al, 2018 ; Wang et al, 2018 ; Sureka et al, 2019 ; Henke et al, 2020 ), can be thereby deposited in continuous films to form responsive biocoatings ( Figures 9B,C ).…”

“…Smaller enzyme-polymer hybrids, e.g., MOFs, particles or SENs, ( Dong et al, 2018 ; Liu et al, 2018 ; Wang et al, 2018 ; Sureka et al, 2019 ; Henke et al, 2020 ), can be thereby deposited in continuous films to form responsive biocoatings ( Figures 9B,C ). For example, single enzyme nanogels of glucose oxidase are able to assemble into ordered and highly stable films by means of coordination polymers and divalent metals ( Rodriguez-Abetxuko et al, 2019b ). Also, Cu 2+ -based tyrosinase MOFs can be used to fabricate a bisphenol A biosensor ( Wang et al, 2015 ; Lu et al, 2016 ).…”

Protein-based functional hybrid bionanomaterials by bottom-up approaches

“…In addition, the assembly of protein-hybrid bionanomaterials into macroscopic materials, such as films and biocoatings, gives rise to several advantages compared to stablished technologies in homogeneous and conventional heterogeneous catalysis. Indeed, assembled bionanomaterials, as heterogeneous materials, enhance the processability, robustness, and stability of the catalysts [42] [43].…”

“…As result of the high modification density, low concentration of metal cations is needed for the efficient assembly of enzyme nanogels into robust and highly active nanoparticles, so-called Metal-Organic Enzyme Aggregates (MOEAs) [48]. These hybrids have been demonstrated successful not only as new bifunctional biocatalysts that integrate the co-catalysis of the biomolecule and the metal cation in a synergy action, but also as assembled platforms to physically compartmentalize biocatalysts in enzymatic cascade reactions and to coat gold microelectrodes for the electrochemical detection of glucose [43].…”