Construction Of Self-Assembled Short Peptide Hydrogel Functionalized Platform And Its Application In Sensing And Antibacterial

Hydrogels have broad applications in the construction of electrochemiluminescent sensing interfaces and antibacterial interfaces in wound infections.However,the use of organic solvents or cross-linking agents in the synthesis of hydrogels is toxic,the preparation methods are not simple enough,and the mechanical strength is poor,which still limit their application in the fields of electrochemiluminescence and wound infection.Self-assembled short peptide hydrogels have attracted extensive attention in the fields of biomedicine,tissue engineering and regeneration,biosensors,and wound healing due to their easy control and good biocompatibility.Dipeptides are the shortest self-assembling sequences of peptides and have been widely studied due to their small size and simple synthetic methods.Due to the ability to self-assemble into self-supporting hydrogels under physiological conditions,simple and rapid assembly method（within minutes）and excellent biocompatibility,Fmoc-FF（N-fluorene methoxycarbonyl-diphenylalanine）has been widely used in sensor,biomedical and industrial fields.In addition,Fmoc-FF can also be used as an assembly module to self/co-assemble into functionalized hydrogels with other materials such as inorganic nanomaterials and organic molecules,this enables the construction of new multifunctional hydrogel materials with specific needs.In this paper,the construction of new hydrogel interface is studied.Based on Fmoc-FF as an assembly module,a functionalized self-assembled hydrogel was constructed,and the sensing interface constructed by nanomaterials and organic molecule-functionalized Fmoc-FF hydrogels and the application of antibacterial materials in ECL sensing and nanoenzyme antibacterial fields are explored.The specific research contents are as follows:1.An electrochemiluminescence（ECL）sensor for highly sensitive and selective detection of Cu²⁺was constructed based on Fmoc-FF self-assembled hydrogels functionalized with black phosphorus quantum dots（BPQDs）.BPQDs were prepared by solvothermal method,and it was found for the first time that BPQDs possessed K₂S₂O₈-dependent cathodic ECL behavior and mechanism.By preparing BPQDs of different sizes and analyzing their ECL spectra,it is found that the ECL of BPQDs is related to both band gap and surface state of BPQDs,and the ECL spectral related to the band gap are red-shifted with the increase of BPQDs.Fmoc-FF dipeptide was used as a hydrogel agent to load BPQDs and K₂S₂O₈ to construct the BPQDs/K₂S₂O₈/Fmoc-FF hydrogel ECL sensing platform.Fmoc-FF hydrogel can stabilize BPQDs by isolating oxygen.In addition,the luminophore BPQDs and co-reacting reagents K₂S₂O₈ confinement in Fmoc-FF hydrogel enhances the ECL signal of BPQDs.Based on the strong interaction between BPQDs and Cu²⁺,a highly sensitive and selective detection of Cu²⁺was achieved.2.An ECL sensing platform combining three-dimensional（3D）culture and 3D detection was constructed based on N-（4-aminobutyl）-N-ethylisoluminol（ABEI）functionalized Fmoc-FF self-assembled hydrogel for in situ monitoring of H₂O₂ released from human breast cells.Taking advantage of the properties of Fmoc-FF as an assembly module,the ECL luminophore ABEI was introduced into the process of Fmoc-FF self-assembly,and an ABEI/Fmoc-FF hydrogel with both 3D cell culture and ECL sensing functions was prepared.The nickel foam（NF）electrode with 3D porous structure is matched with ABEI/Fmoc-FF hydrogel for 3D culture and 3D detection,and the sensor exhibits excellent performance for the detection of H₂O₂ with a wide linear range（0.001–80μM）and a low detection limit of 1.8n M,this method can be used for real-time in situ monitoring of H₂O₂ released from three different subtypes of human breast cells.3.Pt nanoparticles（Pt NPs）functionalized Fmoc-FF self-assembled hydrogels for synergistic antibacterial.Pt nanoparticles（Pt NPs）were encapsulated into Fmoc-FF hydrogel through self-assembly.In neutral environment,Pt NPs exhibits 6-fold enhanced oxidase-like and 26-fold peroxidase-like activity after being encapsulated into Fmoc-FF hydrogel.Pt-Fmoc-FF hydrogel exhibited oxidase-and peroxidase-like activities over a wide range of p H values（2.2–10.0）,getting rid of the restriction of p H.Not only that,the significantly reduced CAT-like activity of Pt/Fmoc-FF hydrogel over a wide p H range enables the selective generation of ROS,which is beneficial for antibacterial.More importantly,Fmoc-FF hydrogel as a carrier provided a universal method for other oxide-and peroxidase-like nanomaterials to break the p H limit of nanozymes.In a neutral environment,given the outstanding enhanced OXD-like and POD-like activities of Pt-Fmoc-FF hydrogel,and the antibacterial activity of Fmoc-FF hydrogel itself,Pt/Fmoc-FF hydrogel realized excellent antibacterial effect.This work provides a universal method to break the p H limit of nanozymes,and promotes the biological applications of nanozymes.In this paper,functionalized self-assembled Fmoc-FF hydrogels formed by introducing functional materials（nanomaterials or organic molecules）,this provides a biocompatible and simple-to-prepare sensing platform for highly sensitive detection of small molecules.Through the unique properties of Fmoc-FF,the regulation of nanozymes and the corresponding antibacterial applications are realized.Fmoc-FF functionalized hydrogels have important reference significance for analytical sensing and performance regulation of nanomaterials.