Construction Of Multiple Dimensional Nanozymes Based On The Supramolecular Assembly Strategies

Enzyme is the gift of biological evolution.Enzyme use the protein as main scaffold and contain an active pocket or catalytic cofactor.It can not only catalysis reaction with high efficiency but also mediate most of the biochemical reactions in the organism.However,its application in real life is always limited because of the drawbacks such as highly cost,complicated preparation/purification,easy inactivation,and poor cyclic utilization.As an attractive functional nanomaterial,nanozyme can simulate the catalytic properties as the natural enzyme but also overcome the disadvantages of natural enzyme.Nowadays,nanozyme have been widely applied in pollutants treatment,chemical warfare degradation,molecular sensing,industrial production,new energy,biomedicine etc.The synthesis of nanozyme indeed meet the demands for catalyst in production and daily life,more important,it also puts forward feasible solutions for medical and health problems such as antibacterial,anti-infection,cancer treatment,early diagnosis and drug innovation,revealing the nanozyme great prospects in further development.In recent years,various reports about nanozyme and their synthetic methodology have come out.It is summarized that there are mainly three strategies for preparing nanozyme.1.Using nanoscale materials with enzyme-like catalytic activity,such as metal nanoparticles,carbon materials,metal compounds,or their composites to synthesize nanozyme.They exhibit the catalytic activities due to the surface and interface effects,electron transfer and redox properties.2.Mimicking the active site of natural enzyme to prepare nanozyme.Following this strategy,people try to prepare nanocomposite according to the catalytic mechanism of natural enzyme or load the catalytic center onto a suitable scaffold which can improve their catalytic and other properties.It is common as carbon materials,nanometers,biological macromolecules and so on.The catalytic centers can be affected by the functional groups,electron transfer capacity,and the microenvironment of the scaffold.3.Immobilization and stabilization of natural enzymes to obtain nanoscale enzymes.Encapsulation,in-situ mineralization and polymerization can form a protective shell on the surface of unstable natural enzymes,which effectively reduces the digestion of protease,protein frameworks denaturation and destruction of catalytic pockets,resulting in a stronger nanozymes.However,Utilizing the more convenient supramolecular assembly strategy to prepare nanozyme with multiple dimensions and fine structures is little discussed and reported.Supramolecular assembly refers to the multi-molecule aggregation driven by the noncovalent supramolecular interactions,which are very extensive,including hydrophobicity,electrostatic,host-guest,metal ion coordination,hydrogen bond,Van der Waals,and pi-pi interactions.Supramolecular assembly is also common,such as bone,muscle fibers,cell membranes,organelles,microtubules and so on.In the field of supramolecular assembly,the main exploration is to drive components into ordered structures with a certain arrangement.The supramolecular assembly can not only show more excellent properties than the single molecule,but also,demonstrate the monomer enrichment,easy modification,easy preparation,recyclability,self-healing,reversibility and stimulus response.Therefore,the supramolecular assemblies with multi dimension suggest characteristics such as fine structure,controllable microenvironment,and environmental response etc.Nowadays,supramolecular assembly with various morphologies and functions has been reported.Therefore,supramolecular assembly not only has the potential for the preparation of traditional nanozymes,but also provides a novel strategy for the preparation of more active and intelligent nanozymes in the future.By using different supramolecular interactions to construct accurate scaffold and introducing catalytic center via mineralization and co assembly,we herein focus on explore a universal method to prepare nanozyme based on supramolecular assembly strategy.In detail,by using coiled-coil interaction,metal coordination and amphiphile assembly strategy,we successfully constructed one-,two-and three-dimensional nanozyme with protein biomacromolecules and supramolecular amphiphiles as building blocks.1.Construction of one-dimensional silver nanoparticle-protein assembly nanozyme based on coiled-coil driven supramolecular assembly strategyThe precision nanostructures and aggregation effects of supramolecular assembly result in the constraint of protein movement and higher local concentration,leading nanozyme with excellent stability and high activity.In this chapter,we attempt to construct a one-dimensional nanozyme with coiled-coil driven assembly strategy.We first precisely design the amino acid sequence and length of coiled-coil peptides to guarantee the orientation and stability of coiled-coil heterodimer.After fusing to the C terminal of Smac/DIABOL,coiled-coils could drive Smac protein to form a stable one-dimensional nanostructure.At the same time,Smac,as a carboxyl group-richen protein on the surface,can effectively adsorb the Ag ions for biomineralization.And we finally successfully prepare a one-dimensional Ag NPs-protein assembly nanozyme composite.By means of electron microscopy,we observe the protein nanowires and the final one-dimensional Ag NPs-protein assembly nanozyme composite.The study also demonstrates that the nanozyme composite has higher catalytic activity and better stability than the traditional Ag nanozyme,this benefits from the compact structure and high local nanoparticle concentration caused by the supramolecular assembly strategy.Meanwhile,the protein surface also provides favorable microenvironment for the catalysis and better solubility,further improving the properties of the one-dimensional nanozyme.This work provides an effective approach for preparing highly active and water-soluble metal and metal compound nanozymes.2.Construction of two-dimensional SOD nanozyme based on metal coordination supramolecular assembly strategyWith the development of nanozyme,people have found that many of their activity are closely related to the properties of corresponding metal ions.Besides,the metal coordination as a specific,strong and reversible supramolecular force can be accurately designed to achieve multiple dimensional nanostructures using from small molecular to protein as building blocks,revealing the glamour of the metal coordination in preparing exquisite structures.Continuing the design and construction of one dimensional nanozyme by coiled-coil assembly strategy,we herein aim to build a more compact two-dimensional nanomaterial by using the controlled metal coordination supramolecular interaction.We first design four Zn ion coordination sites on the Smac dimeric protein through point mutagenesis.,the quadrilateral coordination sites could mediate Smac protein extend along two directions with addition of Zn ion and form two-dimensional materials.Besides,by doping redox Cu ions,we successfully obtained the two-dimensional nanozyme with superoxide dismutase-like activity.The microscopical measurement confirmed our design and the dense two-dimensional material.After assembling with copper ions,we observed similar structure of two dimensional nanozyme,which shows the activity of superoxide dismutase and inhibit oxygen free radicals.This suggests that we have successfully constructed a two-dimensional nanozyme with metal coordination strategy.It is worth noting that the second structure of the two-dimensional does not change at 85 degrees,however the signal of the protein element is almost disappearing.At the same time,the two-dimensional material also demonstrate stability for denature agent.The excellent stability of two dimensional nanomaterials is due to the dense and ordered nanostructure.This work shows us the feasibility of constructing two dimensional nanomaterials by supramolecular assembly strategy and provides an approach for future preparation of stable artificial enzymes catalyzed by metal ions.3.Construction of three-dimensional HRP nanozyme based on supramolecular amphiphiles co-assembly strategyCyclodextrin is a series of water soluble cyclic oligosaccharides,which are used as nontoxic additives or small molecular catalysts by or covalent modification in the early stage.Although soluble in water,cyclodextrins have hydrophobic cavities,which can specifically recognize with guest molecules trough hydrophobic interaction and cavity size.With the development of host-guest assembly and cyclodextrins based supramolecular amphiphilic,the multiple morphologies(such as lines,vesicles,nanotubes,lamellae,etc.)and responsive materials have been reported,revealing its potential for material preparation.After successfully constructing one-and two-dimensional nanomaterials in above chapter,we here attempt to prepare a nanozyme with higher dimension,better enzymology and stability.In this chapter,we modified the natural HRP active site related heme and histidine onto cyclodextrins.After combining with the hydrophobic guest,the two supramolecular amphiphilic molecules can assemble in aqueous solution to form a stable three-dimensional tubular HRP nanozyme.This supramolecular amphiphilic co-assembly strategy is not only simple,more important,it could also construct the same microenvironment as HRP enzyme.The nanozyme showed good HRP catalytic activity.Meanwhile,we found that this amphiphilic nanozyme demonstrate faster reaction rate,thermal stability,p H stability,hydrogen peroxide tolerance and good storage capacity compared with natural HRP.Based on the outstanding stability,we apply it on preparation of glucose test paper.This work demonstrates that supramolecular amphiphilic assembly strategy could be utilizes to construct stable nanozyme and provides ideas for designing and mimicking the active center of natural enzyme,enhancing the catalytic efficiency of nanozymes.