Construction Of Porous Gel And Hemoglobin Catalytic Functional System And Its Preliminary Medical Application

Hydrogel is a natural material of polymer,which can be well swelled after the water absorbance.It possesses the high biocompatibility and biodegradability with very popular applications in bioorganic engineering fields.In the present thesis,three kinds of porous hydrogel scaffolds or matrix materials were fabricated separately by covalently coupling gelatin?Gel?,p-hydroxyphenyl-propionic acid?HPA?,and tyramine?Tyr?.They were employed to encapsulate the enzymes or substrates of enzymatic catalytic reactions in combination with the catalysis of hemoglobin?Hgb?in the blood and / or glucose oxidase?GOD?.On the one hand,the resulting porous hydrogel complex materials were applied for the rapid sensing analysis of analytes?occult blood or blood sugar?.On the other hand,they were exploited to develop functional materials with the sterilization and fast hemostasis functions by way of the changes of physicochemical properties that are induced by the enzymatic catalysis reactions upon the analyte binding.The so designed porous hydrogels with multiple functions should find the wide applications in the sensing,fast hemostasi,and drug delivery fields.?1?A porous hydrogel scaffold was fabricated by covalently coupling Gel with HPA resulting in the Gel-HPA-TMB composites for the in-site encapsulation of catalytic chromogenic reaction substrates of 3,3,5,5-tetramethylbenzidine?TMB?and H₂O₂ onto the aminederivatized capillary tubes.A colorimetric platform of occult blood tests?OBT?with capillary arrays was thereby constructed for the visual and high-throughput detection of Hgb targets.Here,the capillary tubes could offer a space-confined micro-environment for the Hgb-catalytic chromogenic reactions to realize rapid and sensitive analysis.In particular,the capillarity-enabled automatic sampling could also be expected.Moreover,the hydrogel composites with a porous structure could allow for the TMB-H₂O₂ substrates to be largely and firmly anchored onto the capillary tubes.Also,the introduction of specific Hgb-catalyzed chromogenic reactions would help to achieve the highly selective OBT analysis.The practical application feasibility of the developed capillary array-based analysis method was demonstrated for rapid and high-throughput OBT evaluations by probing the Hgb levels in human excreta?i.e.,saliva,urine,and feces?.?2?An injectable functional hydrogel material was prepared by the cross-linking reaction between Gel and Tyr by the cross-linking chemistry,followed by the in situ encapsulation of H₂O₂.The so obtained H₂O₂-encapsulated Gel-Tyr hydrogels could serve as the haemostatic biomaterial for bleeding wound through the Hgb-catalyzed coupling reaction of Gel and Tyr via the oxidation of H₂O₂ leading to the strong coagulation of hydrogel at wound so as to fast prevent the bleeding.Moreover,the haemostatic hydrogel with the porous structure of high density present a protective barrier and moist environment for the wound recovery.This rapid injectable hemostatic hydrogel with haemostatic,drug delivery,antibacterial properties promise the potential applications in the research fields of biomedical materials and tissue engineering.?3?A new kind of network-like hydrogel complex material was synthesized by using Gel,HPA,and Tyr through the covalent chemistry.The so obtained porous hydrogel polymer of Gel-HPA-Tyr was applied to encapsulate GOD to develop a sensitive sensor for blood glucose by using quartz crystal microbalance?QCM?.Herein,the GOD-encapsulated hydrogels were added into the QCM reaction cells.The addition of blood glucose would produce H₂O₂ so as to trigger a hydrogel coagulation process resulting from the Hgb-catalyzed and coupling reaction of HPA and Tyr residues via the oxidation of H₂O₂.As a result,the frequency changes of QCM could occur owing to the sol-gel change of Gel-HPA-Tyr.A linear relationship between the concentrations of blood glucose and frequency changes of QCM was rationally obtained,thus achieving a fast,simple and sensitive detection for blood glucose.This QCM analysis method with functional hydrogels may be widely extended for the clinical analysis of blood glucose.