Patent Publication Number: US-8967218-B2

Title: Alginate-containing wound dressing, method and apparatus for making the same

Description:
RELATED APPLICATIONS 
     The present application is a divisional of U.S. application Ser. No. 12/648,107, filed on Dec. 28, 2009, which claims priority to Taiwan application no. 98125403, filed Jul. 28, 2009. The entire disclosures of the above applications are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Field of Invention 
     The present disclosure relates to a wound dressing; more particularly to an alginate wound dressing. 
     2. Description of Related Art 
     Generally, skin wounds should be kept relatively dry so as to facilitate the healing process of the wounds may. Hence, gauzes are conventionally used to keep the wounds sterile and dry. However, gauzes may sometimes adhere to the tissues or exudates of the wound. Such adhesion may result in a secondary damage to the tissues around the wound during the removal of the gauzes. 
     Recently, it is established that a moistening environment may facilitate the healing of the wounds. The fluids secreted by the wound may contain various growth factors that are advantageous to the wound healing. These findings lead to the development of sealing wound dressing such as polyurethane membranes, or wound dressings containing materials such as chitin/chitosan, collagen or alginate. 
     Main components of alginates or alginate compounds are algal polysaccharides extracted from natural algae. Commercially available alginate wound dressings may be in the form of non-woven fabrics, membranes and sponges. For example, wound dressing KALTOSTAT® provided by BritCair, UK is in the form of non-woven fabrics. 
     Nevertheless, several disadvantages may be associated with existing alginate wound dressing in the form of non-woven fabrics. For example, physiological saline is usually applied to the wound tissues to wash away the remaining gels and exudates during the wound dressing removal process. However, the non-woven fabrics may usually break upon the washing treatment. Besides, conventional non-woven fabrics of the wound dressing are often made of chopped fibers (staples), which tend to come off the non-woven fabrics and adhere to the wound tissues to form short piles that may slowdown the healing of the wounds. 
     In view of the foregoing, there exists in the related art a need for a novel alginate wound dressing. 
     SUMMARY 
     The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the present invention or delineate the scope of the present invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later. 
     The present disclosure provides a novel alginate-containing wound dressing that may prevent the problems such as short piles and breakage encountered by conventional non-woven alginate-containing wound dressings. Due to the relatively low breaking strength, the wound dressing may break or adhere to the wound thereby causing the formation of short piles during the removal of the conventional alginate-containing wound dressing from the wound. 
     In view of the foregoing, in one aspect, the present invention is directed to a novel wound dressing comprising fibers made from alginates (also known as alginate filaments). According to the present disclosure, the breaking strength of the wound dressing may be improved by controlling the length and arrangement of the fibers. 
     According to one embodiment of the present invention, the wound dressing comprises two fiber layers. The first fiber layer consists of a plurality of a first fiber that are made of an alginate wherein the first fibers are respectively bound with one another, and are substantially extended in parallel along a first direction. The second fiber layer consists of a plurality of a second fiber that are made of an alginate, wherein the second fibers are respectively bound with one another, and extend in parallel along a second direction that is not parallel to the first direction. The second layer is stacked on the first layer with the second fibers being bound with the first fibers. The first fibers and the second fibers respectively have a length such that the wound dressing has a breaking strength for at least 1.5 kg. 
     In another aspect, the present invention is directed to a method for making alginate-containing wound dressings with improved breaking strength. 
     According to one embodiment of the present invention, the method comprises the steps as follows. First, at least one alginate fiber is formed by a wet spinning process. The alginate fiber thus obtained is wound around a board thereby forming a plurality of a first fiber on a surface of the board. In this step, the first fibers extend in parallel along a first direction. Thereafter, an aqueous solution containing sodium ions is sprayed on the surface of the wound first alginate fibers. Then, the alginate fiber is rewound around the board thereby forming a plurality of second fibers that are stacked on the first fibers, wherein the second fibers extend in parallel along a second direction that is not parallel to the first direction. The first fibers and the second fibers are dried so that the first fibers and the second fibers are respectively bound with one another. 
     In yet another aspect, the present invention is directed to an apparatus for making alginate-containing wound dressings. 
     According to one embodiment of the present invention, the apparatus comprises a base; a slot disposed on the base and having two ends; a tension compensator slidably connected to the slot and being operable to connect to at least one fiber; and a take-up device. The take-up device comprises a shaft that rotates upon being driven, wherein the shaft is aligned with a level between the two ends of the slot; and a board secured on the shaft for winding the fiber connected to the tension compensator. 
     Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein: 
         FIG. 1A  is a schematic diagram illustrating the wound dressing according to one embodiment of the present disclosure; 
         FIG. 1B  is a photo of a wound dressing according to one embodiment of the present disclosure; 
         FIG. 2  is a flow chart illustrating the method for making a wound dressing according to one embodiment of the present disclosure; 
         FIG. 3A  to  FIG. 3F  respectively illustrate a process for making wound dressing according to another embodiment of the present disclosure; 
         FIG. 4  is a front view illustrating an apparatus for making wound dressings according to one embodiment of the present disclosure; 
         FIG. 5A  and  FIG. 5B  respectively illustrate the various operational status of the apparatus of  FIG. 4 ; 
       Each of  FIG. 6A  to  FIG. 6C  is a rear view illustrating an apparatus for making wound dressings according to various embodiments of the present disclosure; 
         FIG. 7  is a partially enlarged schematic diagram illustrating the apparatus of  FIG. 4 ; 
         FIG. 8A  and  FIG. 8B  are cross-sectional view taken along line  8  of  FIG. 4  and each illustrates an operational status of the reciprocating device. 
     
    
    
     Like reference numerals are used to designate like parts in the accompanying drawings. 
     DETAILED DESCRIPTION 
     The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples. 
       FIG. 1A  is a schematic diagram illustrating the wound dressing  100  according to one embodiment of the present disclosure; whereas  FIG. 1B  is a photo of the wound dressing  100  according to one embodiment of the present disclosure. 
     Wound dressing  100  of the embodiment of the present disclosure mainly comprises fibers made from alginates. The breaking strength of the wound dressing  100  may be improved by controlling the length and arrangement of the fibers. Hence, problems such as short piles and breakage encountered by conventional non-woven alginate-containing wound dressings can be avoided. 
     In the present disclosure, the term “breaking strength” refers to the force applied on the wound dressing while the wound dressing breaks. In the working examples presented hereinafter, the breaking strength of the wound dressing is measured according to ASTM standard D 3822-2007 (Standard Test Method for Tensile properties of Single Textile Fibers). 
     The wound dressing  100  comprises two fiber layers—a first fiber layer  110  and a second fiber layer  120 . Fibers of the two fiber layers are fibers with relatively long length. The breaking strength of the wound dressing  100  may be improved by designing the length and arrangement of the fibers of the first fiber layer  110  and the second fiber layer  120 . Each element of the wound dressing  100  and characteristics thereof are set forth hereinafter. 
     The first fiber layer  110  consists of a plurality of a first fiber  112  that are made of an alginate wherein the first fibers  112  are respectively bound with one another. The first fibers 112  are substantially extended in parallel along a first direction, which is referred to as the first direction  130  hereinafter. 
     The second fiber layer  120  is stacked on first fiber layer  110 . The second fiber layer  120  consists of a plurality of a second fiber  122  that are respectively bound with one another. The second fibers  122  are also made from alginate. The second fibers  122  are extend in parallel along a second direction, which is referred to as the second direction  132 . The second direction  132  is not parallel to the first direction  130 . 
     According to the embodiments of the present disclosure, the second fibers  122  are flatly disposed on and adhered to the first fibers  112  when the second fiber layer  120  is stacked on first fiber layer  110 . In other words, the first fibers  112  and the second fibers  122  are solely adhered rather than woven with each other; that is, each of the first fibers  112  would not wind around each of the second fibers  122 . 
     The first fibers  112  and second fibers  122  are all made from alginate, which is extracted from natural marine algae. Main components of the alginic acid molecule include β-D-mannuronic acid and α-L-guluronic acid that are irregularly arranged across the polymer chains. The polymer chains usually links with one another with the alternating β-D-mannuronic acid and α-L-guluronic acid or the polymeric alternating [β-D-mannuronic acid and α-L-guluronic acid] n. According to embodiment of the present disclosure, examples of alginate may include, but are not limited to, calcium alginate, barium alginate, copper alginate, zinc alginate, silver alginate or iron alginate. 
     According to the embodiments of the present disclosure, the first fibers  112  are bound with the second fibers  122  so as to improve the breaking strength of the wound dressing  100 . During the manufacturing process, aqueous solution containing sodium ions can be sprayed onto the surfaced of the formed alginate fibers such as the first fibers  112  so that the surface of the fibers may be slightly dissolved or soften whereby producing viscose to bind any two adjacent first fibers  112 . After the viscose is dried, the first fibers  112  are bound to one another. The second fibers  122  can be prepared by the above-mentioned method. Furthermore, the aqueous solution containing sodium ions may be sprayed on the surface of the first fiber layer  110 ; afterward, the second fiber layer  120  is stacked on the first fiber layer  110 . As such, the first fibers  112  may adhere to the second fibers  122 . 
     Aqueous solution containing sodium ions  320  may be a sodium chloride aqueous solution. The concentration of the sodium chloride in the aqueous solution may depend on the operation parameters. In one embodiment of the present disclosure, the sodium chloride is in an amount of about 1 wt % to about 15 wt %. For example, the concentration of the sodium chloride in the aqueous solution may be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 wt %. In one working example presented hereinafter, the sodium chloride is in an amount of 10 wt %. 
     Conventional wound dressings made of non-woven fabric consists of alginate staples. The breaking strength of such conventional wound dressing is about 1.493 kgf. Such breaking strength is not sufficient to cope with the force applied during the removal of the wound dressing thereby causing problems such as wound dressing breakage and short piles formation. As such, according to the principles and spirits of the present disclosure, the first fibers  112  and the second fibers  122  should respectively have a sufficient length such that the wound dressing has a breaking strength for at least about 1.5 kgf. 
     According to embodiments of the present disclosure, the first fibers  112  and the second fibers  122  are both in a form of filaments. Each filament has a length no less than about 1 cm such that the breaking strength of the wound dressing is at least about 1.5 kgf. 
     It is well known that within a suitable range, the longer the fibers are, the higher the linear strength of the fiber. In the present disclosure, the linear strength represents the tensile of the fiber. Hence, the higher the linear strengths of the first fibers  112  and the second fibers  122  are, the higher the breaking strength of the wound dressing  100 . 
     According to the embodiments of the present disclosure, breaking strengths of three samples were measured in accordance with the ASTM standard D 3822-2007. The lengths of the first fibers  112  and second fibers  122  of each of the samples were different from one another. The lengths of the fibers and test results are summarized in Table 1. As shown in Table 1, the lengths of the first fibers  112  and the second fibers  122  provide sufficient linear strength so that the breaking strength of the wound dressing  100  is in a range of about 107 kgf to about 109 kgf. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Length of the 
                 Length of the 
                 Breaking strength 
               
               
                 1 st  fibers (cm) 
                 2 nd  fibers (cm) 
                 (kgf) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 5 
                 7 
                 108.339 
               
               
                 10 
                 12 
                 107.773 
               
               
                 15 
                 20 
                 108.813 
               
               
                   
               
            
           
         
       
     
     Hence, according to various embodiments of the present disclosure, each of the first fibers  112  and each the second fibers  122  may respectively have a sufficient length so that the breaking strength of the wound dressing is in a range of about 100-109 kgf. Specifically, the breaking strength may be about 100, 101, 102, 103, 104, 105, 106, 107, 108, or 109 kgf. 
     As can be concluded from the examples summarized in Table 1, each of the first fibers  112  and each of the second fibers  122  may have a respective length in the range of about 5-20 cm so as to achieve the breaking strength specified above. In particular, the length of the each of the first and second fibers can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 cm. 
     Furthermore, in the examples shown in Table 1, the length of the first fibers  112  is equal to or slightly smaller than the width of the wound dressing  100 , and the length of the second fibers  122  is also equal to or slightly smaller than the length of the wound dressing  100 . Such arrangement is also suitable in other embodiments of the present disclosure. 
     The first fibers  112  extend in a direction parallel to the first direction  130 , whereas the second fibers  122  extend in a direction parallel to the second direction  132  that is not parallel to the first direction  130 . In other words, there is an included angle between the first direction  130  and the second direction  132 , wherein the included angle is in a range between about 0° to 180°, both ends excluded. The included angle may be, for example, about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, or 175 degrees. According to one optional embodiment of the present disclosure, the first direction  130  is substantially perpendicular to the second direction  132 . 
     Therefore, in the wound dressing  100 , the breaking strength in each direction can be improved by selecting suitable lengths and extending directions of the first fibers  112  and second fibers  122 . In particular the breaking strength in the directions of the first direction  130  and second direction  132  may be improved. 
     It should be noted that although wound dressing  100  having two fiber layers are illustrated in the above embodiments, the wound dressing  100  may have more than two fiber layers, such as three, four, five or more fiber layers. In the latter case, the extension direction of fibers in each of the fiber layers may be non-parallel to the extension directions of fibers in other fiber layers. 
       FIG. 2  is a flow chart illustrating the method  200  for making the wound dressing  100  according to one embodiment of the present disclosure.  FIG. 3A  to  FIG. 3F  are schematic diagrams illustrating the process steps for making the wound dressing  100  according to one embodiment of the present disclosure. 
     Please refer to  FIG. 2  and  FIG. 3A . The first step  210  of the method  200  for making the wound dressing  100  is forming alginate fibers. In step  210 , at least one alginate fiber  310  can be formed by a wet spinning process. Specifically, the wet spinning process comprises the steps as follows. Alginate compounds are dissolved in an aqueous solution to form a spinning solution. From a spinning nozzle, the spinning solution is injected into a molding basin containing divalent metal ions (M 2+ ) so that the spinning solution is injection molded into a solid, insoluble alginate fiber  310 . According to the embodiments of the present disclosure, the alginate compounds may be calcium alginate, barium alginate, copper alginate, zinc alginate, silver alginate or iron alginate. 
     Alternatively, after the alginate fiber  310  is formed, the alginate fiber  310  can be extended by a drafting process so as to adjust the linear strength of the alginate fiber  310 . The drafting process can be performed by a drafting roller assembly. The structure of the drafting roller and the method for drafting the fibers are known to those skilled in the art, and hence are not described in detailed in the present disclosure. 
     In step  220 , the alginate fiber  310  is wound around a board  300 . After winding, the alginate fiber  310  would be arranged in parallel on a surface of the board  300  as a plurality of fragments. In the present disclosure, one fragment of the alginate fiber  310  disposed on a surface of the board  300  is referred to as a first fiber  112 . The length of the first fibers  112  is equal to or slightly smaller than the length of the board  300 . According to the embodiments of the present disclosure, the length of each of the first fibers  112  is in a range of about 5 cm to about 20 cm. Specifically, the length can be about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 cm. 
     Please refer to  FIG. 2  and  FIG. 3B . Step  230  is carried out after the winding the alginate fiber  310 . In step  230 , an aqueous solution containing sodium ions  320  is sprayed on the surface of the wound alginate fiber  310 . Spraying the aqueous solution containing sodium ions  320  over the surface of the solidified alginate fiber  310  may slightly dissolve or soften the surface of the alginate fiber  310  whereby producing viscose. The adjacent fragments of the alginate fiber  310  (i.e., first fibers  112 ) would be adhered together by the viscose. After the viscose is dried, the adjacent fragments would bind with one another. 
     The aqueous solution containing sodium ions  320  may be a sodium chloride aqueous solution. The concentration of the sodium chloride in the aqueous solution may depend on the operation parameters. In one embodiment of the present disclosure, the sodium chloride is in an amount of about 1 wt % to about 15 wt %. For example, the concentration of the sodium chloride in the aqueous solution may be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 wt %. In one working example presented hereinafter, the sodium chloride is in an amount of 10 wt %. 
     Please refer to  FIG. 2 ,  FIG. 3C  and  FIG. 3D . After the first winding step is accomplished, the board  300  is rotated as shown in  FIG. 3C . Afterward, in step  240 , the alginate fiber  310  is re-wound around the board  300  as shown in  FIG. 3D . After this re-winding step, the alginate fiber  310  would be arranged in parallel on a surface of the board  300  as a plurality of fragments, which are referred to as second fibers  122 . The length of the second fiber  122  is equal to or slightly smaller than the length of the board  300 . According to the embodiments of the present disclosure, the length of each of the second fibers  122  is in a range of about 5 cm to about 20 cm. Specifically, the length can be about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 cm 
     The second fibers  122  are stacked on the first fibers formed on the board  300  during the first winding step (step  220 ). It should be noted that the board  300  is rotated between the first (step  220 ) and second (step  240 ) winding steps such that the extension direction of the first fibers  112  is different from that of the second fibers  122 . In other words, the rotation angle of the board  300  is equal to the included angle between the extension directions of the first fibers  112  and the second fibers  122 . For the purpose of illustration, the board  300  can be rotated with an angle in the range of about 0-180 degrees, both ends excluded. For example, the rotation angle can be about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, or 175 degrees. According to one optional embodiment of the present disclosure, the board  300  is rotated at an angle of about 90 degrees. 
     Please refer to  FIG. 2 ,  FIG. 3E  and  FIG. 3F . After the re-winding step, the wound dressing  100  can be obtained by cutting the fibers along the peripheral of the board  300 , as shown in  FIG. 3F . 
     Afterward, step  250  is carried out to dry the alginate fibers. As illustrated hereinabove, spraying the aqueous solution containing sodium ions  320  on the surface of the solidified alginate fibers  310  would cause the formation of viscose. After the viscose is dried, the adjacent alginate fibers  310  would be bound with one another. 
     According to the embodiments of the present disclosure, the alginate fibers  310  may be dried by freeze-drying. The freeze-drying technique can be embodied in various method, and the temperature and pressure used in the freeze-drying process may be process-dependent. According to embodiments of the present disclosure, the temperature for the freeze-drying is about −55° C. to about −20° C., and the pressure is about 12 pascals. 
     It should be noted that although steps of the method according to embodiments of the present disclosure are recited in a specific sequence, the method is not limited thereto. That is, unless the sequence of the steps is expressly indicated, the sequence of the steps is interchangeable, and all or part of the steps may be simultaneously, partially simultaneously, or sequentially performed. In addition, each step may be performed more than once. For example, the step of spraying the aqueous solution containing sodium ions  320  and the step of winding alginate fibers  310  can be performed more than once. 
     Besides, the step of spraying the aqueous solution containing sodium ions is not limited to be performed after the first winding step (step  220 ). In fact, the spraying step can be performed simultaneously with and/or after the first winding step (step  220 ) and/or the re-winding step (step  240 ). 
       FIG. 4  is a front view illustrating an apparatus  400  for making wound dressings  100  according to one embodiment of the present disclosure. The apparatus  400  comprises a base  410 , a take-up device  420  and a tension compensator  430 . The take-up device  420  is operable to wind the alginate fiber  310 . The take-up device  420  may comprises a shaft  422  and a board  300 , wherein the board  300  is secured on the shaft  422 . When the shaft  422  is rotated (for example, rotated along direction  402  shown in  FIG. 4 ) upon driven, the alginate fiber  310  would be wound around the board  300 . 
     The shape of the board  300  is different from that of the conventional cylindrical beaming. As such, during the take-up process, the length of the alginate fiber  310  may be altered in an excess level thereby altering the tension of the alginate fiber  310 . To address such problem, a tension compensator  430  is disposed in front of the take-up device  420  so as to maintain the tension of the alginate fiber  310  during the take-up process. 
     Specifically, a slot  412  is disposed on the base  410  and is adjacent to the shaft  422 . The slot  412  has two ends defining a lengthwise direction. The shaft  422  is disposed at a place so that the shaft  422  is aligned with a level between the two ends of the slot  412 . The tension compensator  430  is disposed in the slot  412  and operable to slide in the lengthwise direction of the slot  412 . 
     The tension compensator  430  is operable to connect to the alginate fiber  310 . The tension compensator  430  may adjust the tension of the alginate fiber  310  by altering its altitudinal position in the slot  412 . Please refer to  FIG. 5A  and  FIG. 5B , which respectively illustrates the various operational status of the apparatus  400  of  FIG. 4 . When an edge  304  of the board  300  is rotated to a position lower than the altitude of the shaft  422 , the tension compensator  430  may slide to a lower altitudinal position in the slot  412 . For example, the tension compensator  430  may slide to a position lower than the shaft  422 , as shown in  FIG. 5A . On the other hand, when the edge  304  of the board  300  is rotated to a position higher than the altitude of the shaft  422 , the tension compensator  430  may slide to a higher altitudinal position in the slot  412 . For example, the tension compensator  430  may slide to a position higher than the shaft  422 , as shown in  FIG. 5B . 
     As such, the length variation of the alginate fiber  310  between the tension compensator  430  and the edges  302  or  304  can be decreased thereby maintaining a stable tension of the alginate fiber  310 . 
     It should be noted that the length of the slot  412  is not limited in the embodiments of the present disclosure. For example, when one of the edges  302  or  304  of the board  300  is rotated to the highest position, said highest position may be higher or lower the upper end of the slot  412 . When one of the edges  302  or  304  of the board  300  is rotated to the lowest position, said lowest position may be higher or lower the lower end of the slot  412 . In one embodiment, when the edge  304  of the board  300  is rotated to the highest position, the upper end of the slot  412  is substantially aligned with the middle of the edge  304  and the shaft  422 . When the edge  304  of the board  300  is rotated to the lowest position, the lower end of the slot  412  is substantially aligned with the middle of the edge  304  and the shaft  422 . 
     According to the embodiments of the present disclosure, the length of the slot  412  may be smaller than one-fold or two-fold the distance between the shaft  422  and the edge  304  of the board  300 . 
     Tension compensator  430  may be reciprocatively slide in the lengthwise direction of the slot  412  under the pulling motion of the alginate fiber  310 . That is, when the alginate fiber  310  is rotated to a position higher than the shaft  422  under the rotating motion of the board  300 , the alginate fiber  310  may pull the tension compensator  430  to slide upward. On the contrary, when the alginate fiber  310  is rotated to a position lower than the shaft  422  under the rotating motion of the board  300 , the alginate fiber  310  may pull the tension compensator  430  to slide downward. 
     Alternatively, the tension compensator  430  may couple with the shaft  422  by means of gear, screw, strap, cam, link lever or other mechanical members. Hence, the tension compensator  430  may slide along the lengthwise direction of the slot  412  under the driving force provided by the shaft  422 . 
       FIG. 6A  is an illustrative example illustrating the rear view of the apparatus  400  according to embodiments of the present disclosure. As shown in  FIG. 6A , apparatus  400  comprises cam  431 , rod  432  and a banded structure  433  such as a strap. The shaft  422  and cam  431  are connected by the banded structure  433 . On end of the rod  432  connects to the tension compensator  430 , whereas the other end of the rod  432  is against the cam  431 . When the shaft  422  is driven to rotate in the direction  404 , the cam  431  would be driven to rotate in the direction  406  through the action of the banded structure  433 . The cam  431  and rod  432  are disposed in a way such that the cam  431  would push the rod  432  and the tension compensator  430  to slide in the lengthwise direction of the slot  412 . 
     Another example of apparatus  400  is illustrated in  FIG. 6B . The tension compensator  430  is driven by the shaft  422  through the action of the link lever  434 . In particular, the linkage  434  may comprise a mechanism such as crank  435  and a rocking lever  436 . The shaft  422  and the crank  435  are connected by a banded structure  433  such as a strap. One end of the rocking lever connects to the tension compensator  430 , whereas the other end connects to the crank  435 . When the shaft  422  is rotated in the direction  404 , the crank  435  is rotated through the action of the banded structure  433  which in turns may drive the rocking lever  436  to rock so that the tension compensator  430  may reciprocally slide in the lengthwise direction of the slot  412 . 
     Still another example of the apparatus  400  is illustrated in  FIG. 6C . The tension compensator  430  is driven by the shaft  422  through the linkage  434 . Specifically, linkage  434  may comprise a wheel  437  and a rocking lever  436 . Two ends of the rocking lever  436  pivotally connect to the wheel  437  in the proximity of the periphery of the wheel  437  and the tension compensator  430 , respectively. The shaft  422  and the wheel  437  are connected by the banded structure  433  such as a strap  433 . When the shaft  422  is rotated in direction  404 , the wheel  437  would rotate in the direction  406  under the action of the banded structure  433  which in turns would drive the rocking lever  436  to rock, thereby driving the tension compensator  430  to reciprocally slide in the lengthwise direction of the slot  412 . 
     In the above-described examples, a banded structure is used to connect the members. Alternatively, the banded structure  433  can be replaced by a gear set for connecting the shaft  422  and the tension compensator  430 . 
     It is apparent from the examples described above that the tension compensator  430  can be connected to the shaft  422  by means of a cam  431 , a linkage  434  and any other suitable mechanical members so that the tension compensator  430  may move synchronically with the rotation of the shaft  422 . 
     Alternatively, an automated control module can be employed. The automated control module may electrically connect to the shaft  422  so as to detect the rotation of the shaft  422  and adjusting the altitudinal position of the tension compensator  430  based on the result of the detection. 
     The board  300  is detachable; that is, the board  300  can be secured on and detached from the shaft  422 . The apparatus  400  may comprises a clamp  424  fixed on the shaft  422 . The clamp  424  is operable to secure or release the board  300 . As such, during two winding processes, the board  300  can be released, rotated, and then re-secured on the shaft  422 . 
     Examples of clamp  424  for securing the board  300  on the shaft  422  may include, but are not limited to: elastic clamps, C-clamps and combinations thereof. Please refer to  FIG. 7 , which is a partially enlarged schematic diagram illustrating the apparatus  400  according to one embodiment of the present disclosure. According to the embodiments of the present disclosure, clamp  424  may comprises a clamping seat  426  and a screw  428 . The clamping seat  426  is fixed on the shaft  422  and is used for accommodating a portion of the board  300  therein. The screw  428  is secured into the clamping seat  426  whereby securing the board  300  in the clamping seat  426 . The board  300  can be detached from the clamping seat  426  by releasing the screw  428 . 
     To avoid the adherence between the alginate fiber  310  and the board  300 , the board  300  should be made of a material that would not react with the alginate compound, and should have a smooth surface. According to the embodiments of the present disclosure, the material of the board  300  can be acrylic resins. The shape of the board  300  may depends on the desired shape of the product. For example, the shape of the board  300  can be square, rectangle, rhombus, polygonal or circle. 
     Please refer to  FIG. 4 . The apparatus  400  may comprise a reciprocating device  440  disposed in front of the take-up device  420 . The reciprocating device  440  is operable to drive the alginate fiber  310  to reciprocatively move in a direction parallel to an axis of the shaft  422 . As such, the alginate fibers  310  may evenly be distributed on the board  300  during the winding process. 
     Please refer to  FIG. 4 ,  FIG. 8A  and  FIG. 8B .  FIG. 8A  and  FIG. 8B  are cross-sectional view taken along line  8  of  FIG. 4  and each illustrates an operational status of the reciprocating device  440 . 
     The reciprocating device  440  comprises a rod  442  and an actuator  444 . The rod  442  passes through a through-hole  414  on the base  410  and connects to the actuator  444 . The actuator  444  is operable to push the rod  442  so that the rod may reciprocatively move in its extension direction thereby altering the distance between one end of the rod  442  and the through-hole  414 . For example, the distance L 1  between one end of the rod  442   a  to the through-hole (as shown in  FIG. 6A ) is altered to distance L 2  (as shown in  FIG. 6B ). 
     In one embodiment of the present disclosure, the rod  442  is threaded, wherein the thread of the rod  442  is matched with the thread of the through-hole  414 . The actuator  444  is operable to rotate the rod  442  so that the rod  442  may reciprocatively move in its extension direction. Alternatively, the actuator  444  may be a linear actuator which may push the rod  442  to reciprocatively move in its extension direction. 
     The reciprocating device  440  may further comprises a threaded hole  446  disposed at one end of the rod  442 . The alginate fiber  300  may pass through the threaded hole  446 . It should be noted that the threaded hole  446  would not rotate no matter whether or not the rod  442  is in a rotating motion. 
     It should be noted that various structures can be used to drive the alginate fiber  310  to move reciprocatively. Hence, examples provided herein are merely for the purpose of illustration, and the examples should not be regarded as limiting to the scope of the present disclosure. 
     According to the embodiments of the present disclosure, apparatus  400  may comprises a wet spinning module  450  for performing a wet spinning process to produce the alginate fiber  310 . Detailed process for performing the wet spinning process is described hereinabove, and hence is not repeated here. 
     To improve the tension of the alginate fiber  310 , the apparatus may further comprise a drafting roller module  460 . The drafting roller module  460  is used for drafting the alginate fiber  310  so as to adjust the linear strength of the alginate fiber  310 . 
     It will be understood that the above description of embodiments is given by way of example only and that various modifications may be made by those with ordinary skill in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention. Although various embodiments of the invention have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those with ordinary skill in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.