The Preparement And Research Of Composite Alginate Needle-punched Wound Dressings

The applications of alginate fibers in wound dressing originated in the inventionof Wet Therapy. The alginate fiber-based wound dressings、gauzes and bandageshave been widely used when Winter discovered that humid environment can speed upwound healing in1962. Compared with traditional dressings, alginate dressings havesome advantages such as: higher moisture absorption, better hemostatic properties,better bio-compatibility and better gelatinous properties and it could promote woundhealing and stripped painlessly after wound healing. The main mechanismis that whenthe dressings contact sepsis, ions exchange happened between calcium ions of algi-nate fibers and sodium ions in the human body, water-insoluble calcium alginateslowly converted into water-soluble sodium alginate so that a lot of water into the fi-ber to form a hydro-gels inside, which endue the gauze a high moisture absorption,easy to remove and some other excellent performance. Alginate fiber is a new and re-newable fibers which have a great development value, but because of the poor physi-cal and mechanical properties of alginate fiber, difficult to card and expensive rawmaterial prices and higher production costs of dressings, so there is practical signific-ance to research the medical dressings with appropriate production cost and excellentperformances.This paper prepared a new composite medical dressings by needling processusing webs of alginate fibers, viscose, polyester fibers which touched soft andcomfortable, have good moisture permeability, good performance to prevent liquiddiffusion, good bio-compatibility and better gelatinous properties. This papermainly focuses on the following five aspects of works: Firstly, the basic mechanicalproperties of the fiber materials were tested and analyzed; secondly, seven kindsof samples of composite alginate needle-punched medical dressings from differentwebs and different web structure by needling process with different lapping anglesand fibers; thirdly, analyzing the influence of different alginate fiber content anddifferent web structure in the functional layer on the properties of the samplessuch as: the outward appearance, rigid flexible, fluid absorption affect performance,liquid diffusing properties, air permeability and moisture absorption, water extractpH and the content of water-soluble matters; fourthly, selecting a representativesample of L-929fibroblasts were co-cultured by observing cell morphology change and growth and appreciation of science to evaluate the evaluation of the dressing bio-compatibility; last, with the techno-logy of computer image processing to calculate the bore diameter of the web and through the images of alginate fibers andwebs dipped in saline and distilled water photoed by optical microscope within different times to characterize the process to be gel and to testify the theoryof gelatinous properties.Through the research, this paper obtained some main conclusions as following:(1) Alginate fibers have poor physical and mechanical properties, easy to bebroken and less curls. Because the surface of fibers is straight and vertical withouttorsion and there are many different sizes of gaps and holes, while the special struc-tures make it a better moisture absorption.(2) Alginate fiber longitudinal surface is straight without turnings and has a lotof cracks and holes of different sizes, which lead to the defect of alginate fiber, withless curls, prone to be broken in carding.(3) When using acupuncture techniques between different webs, the parametersare: acupuncture frequency f=400times/min, forward speed of dressing V=0.87m/min, needling density S=1716pieces/m, needling depth: h=7mm,which can obtainsoft and fluffy medical dressings up to medical standards.(4) Seven different composite alginate needle-punched wound dressings possessbetter softness and comfortable properties, such as good liquid absorption ability，good moisture and air permeability, good performance to prevent liquid diffusionand so on, meanwhile, chemical performance like the soluble liquid of samples in water is slightly acidic, whose pH is between6.0~7.0, the height of superficial foam almost approach0,and the amount of soluble substance below0.5%,which all conform to medical industry standards.(5) The samples of composite alginate needle-punched medical dressings wereprepared with good bio-compatibility, L-929fibroblast cells can be grown on the sur-face of the sample, the cells were normal and most of the cells are triangular or fusi-form after3days.(6) Alginate fiber has better gelatinous properties and gel obstructive properties, betterliquid absorption,better moisture and oxygen permeability and easy to be removedwithout pain. The processes to become gel are different between the webs of calciumalginate and rayon-based calcium alginate, with the images of the process to be gel tofully testify the theory of gelatinous properties of alginate fibers.