Environmental Responsive Hydrogels

Biomaterials have been widely used in many fields,from bioengineering,medical treatment,environmental monitoring to chemical industry,and become increasingly important these years.In medical field,biaomaterial is one of the suitable material to serve as substitute materials for injured tissues or organisms in body.There are some requirements to meet when designing for such biomaterials.With similar mechanical properties of the tissues and organisms they substitute is the essential criterion.On top of this,similar physiological functions of tissues is also important.In detail,they should be able to detect one or some kinds of stimuli(like light,force,pH,etc)from the environments and make corresponding response.Take the regeneration of cartilage for example,there are two requirements to meet in such designs.The material should own similar mechanical properties with that of cartilage in body as well as the ability to release anti-inflmmation drug in vivo.Biocompatibility of the mateials is indispensable as well.On the other hand,there are also some research about cells involving biomaterials that mimic extra cell matrix(ECM).If this kind of materials can respond to environmental stimuli,it will help develop a series of cell culture platform modulating cell behaviours.In the first chapter,we introduce the materials and experimental methods used in this research.The first part is about the new kind of material involved—hydrogel.It includes the history of the hydrogel research,the design principle of hydrogel system and also the components that can be used to support the hydrogel network.Next some examples about biomaterials responding to environmental stimuli were presented.Then the protein involved in the second project is introduced,that is the light-sensitive flurescent protein LOV2(light-oxygen-voltage).At last,we make a brief introduction of the design in two projects.In the second chapter,we focus on a kind of biomaterial with the aim of curing cartilage inflmamation.We designed a double-network hydrogel based on HA,PEG,Boronic acid and Tannic acid(a kind of dynamic covalent bond will form between Boronic acid and Tannic acid).The dynamic covalent bond between Boronic acid and Tannic acid is easily to break under stress,leading to the release of Tannic acid into the environment to cure inflammation.The mechanical properties of the hydrogel was studied in details and the drug release in response to ultrasound was also demonstrated.In the third chapter,a hydrogel involving the light-sensitive protein LOV2 was studied.A mutation of RGD which can distinguish cells to the DNA sequence of the protein was made.When exposed to blue light,the Ja helix of the protein will unfold and RGD reveals.By introducing this mutated protein into hydrogels,the cell growth can be modulated following the distribution of proteins.Finally,we made a summary of two projects and further presented some discussions about the potential applications of the materials as well as some supplementary experiments that need to finish next.