Preparation Of Superabsorbent And Hydrogel Wound Dressing Through Electron Beam Irradiation

In the new period of peaceful development,the ability to use nuclear technology safely and efficiently in order to serve the civilians has become an important goal for our nation.Within this field,non-power civilian nuclear technology is related most closely to people’s lives.As a branch of the non-power civilian nuclear technology,irradiation technique has been applied to such fields as sterilization,food conservation and material modification through combination with industry,agriculture or medication,forming a giant industrial chain.There are several ways to achieve successful irradiation,among which electron beam irradiation is the most promising one as it is characterized by high efficiency,low energy loss,no radioactive waste residue,low cost.etc.Up to now,investigation around electron beam irradiation mainly focus on sterilization.In order to satisfy increasing social and economic demands,we should make every effort to extend its applications.Superabsorbent(SAP)is a hydrogel polymer which can absorb a large quantity of water.Owing to this ability,they can be used to make sanitary materials,anti-drought materials or food conservative materials,etc.During the reaction process,monomers are polymerized to form crosslinked polymer chains.If the traditional chemical method is employed,toxic initiators and crosslinkers have to be added into the reaction system.However,the irradiation technique can save all these trouble by giving a large amount of energy in a short period of time,which shows it is an efficient way of making SAP.Hydrogel wound dressing also belongs to hydrogel materials.It can adhere to wounds,performing as a barrier against bacterial infection as well as absorbing wound drainage.It is semi-permeable,relatively strong,which are all beneficial for the wounds.Irradiation is a perfect method to prepare wound dressings not only because it is crosslinker-free,but it can achieve crosslinking and sterilization at the same time.In this paper,we prepared SAP and hydrogel wound dressing by electron beam irradiation.Apart from that,we erected an evaluation criterion for hydrogel wound dressing according to the national standards.Detailed contents are listed as follows:(1)Through tuning the acrylic acid(AA)monomer concentration,the AA monomer neutralization,the irradiation dose,we investigated the premium condition in preparing PA A SAP.We found that when the AA concentration is 30wt%,the neutralization is 70%,and the irradiation dose is 12kGy,the swelling capacity for the final product could be 1016.2g/g in distilled water and 98.2g/g in salt solution.When the hydrogel was pulverized into 50-100 mesh,it has the best swelling capacity and swelling velocity.Such results can be a reference in the next stage of investigation.(2)In order to improve the PAA SAP’s salt-resistance and biodegradability,we introduced acrylamide(AM)and y-poly glutamic acid(γ-PGA)into the former system and manufactured ternary copolymerized crosslinked SAP.We employed the taguchi method to find out the ideal preparation condition to be 3wt%γ-PGA,30wt%(AA+AM),AA:AM=4:1,70%neutralization and irradiation dose 18kGy.Under such condition,we could achieve SAP with swelling ratio of 969.2g/g in distilled water and 121.4g/g in salt solution.In comparison to the aforementioned product,swelling capacity in salt solution increased around 20%,and the degradation speed also increased dramatically.(3)We divided the materials for wound dressing into 3 categories:basic material,reinforce material and functional material.Basic material(gelatin)can give the hydrogel its strength and bio-compatibility.Reinforce material(polyvinyl pyrrolidone,γ-PGA)could further add its strength and flexibility,and make it easier to coating.Functional material(tragacanth gum and low-molecular weight chitosan)can improve its antibacterial property and fasten wound healing.(4)We chose gelatin of 240bloom and 16wt%as basic material,and irradiation dose of 25kGy as the irradiation condition.We mixed these 3 kinds of materials together and coating,then we applied electron beam irradiation to crosslink and sterilize them,through which we got the final product.Through tuning PVP concentration,we prepared several different hydrogel wound dressings.We tested its swelling capacity,mechanic strength,water vapor permeability,adherence,and compare them with a Poland product of the same kind.The result showed that our product is similar to or better than the Poland product in all these aspects.We also investigated its cytotoxicity and intradermal reaction to prove that it can be applied safely to human body.