Novel alginate,chitosan,and psyllium composite fiber for wound-care applications

Abstract

Alginate/psyllium and alginate/chitosan fibers have great potential for wound-care applications. However, alginate/psyllium fibers have poor tensile strength and alginate/chitosan fibers comparatively have low liquid absorption properties. The main aim was to develop a tri-component fiber with comparatively better tensile strength and liquid absorption properties using three different natural polysaccharides. Alginate, chitosan, and psyllium composite fibers were made by using two different coagulation bath compositions. In method A, psyllium-containing sodium alginate dope solution was extruded into a bath containing CaCl₂ and subsequently passed through hydrolyzed chitosan bath, whereas in method B: psyllium-containing sodium alginate dope solution was directly extruded into hydrolyzed chitosan and subsequently passed through CaCl₂ bath. The produced fibers were rinsed using 25–100% acetone solutions and dried in air. Tensile, antibacterial, swelling, and absorption properties of these fibers were measured. The study showed that homogeneous fibers can be extruded by using both methods. The fibers produced showed good antibacterial, absorption, and swelling properties. Antibacterial activity of the controlled and composite fibers was more or less the same. However, tensile properties of fibers produced by method A and method B were less than the control alginate–chitosan fibers. The composite fibers produced by method A showed better absorption of saline and solution A than control fiber and composite fibers produced by method B. Therefore, method A is recommended for producing the psyllium-containing alginate chitosan fibers for wound-dressing applications. The fibers produced by this method showed comparable tensile and antibacterial properties, superior absorbency, and swelling properties.

Keywords

Fibrous materials medical textiles strength of materials polysaccharides chitosan alginate

Introduction

Naturally sourced carbohydrate-based materials have promising applications as nutrients, therapeutic agents, and wound dressings. These materials are biocompatible, biodegradable, and environment friendly owing to their origin and remarkable molecular structure. In the last two decades, intensified efforts have been made in identifying biological functions of different polysaccharides with relation to their biomedical applications [1,2].

On one hand, polysaccharides appear in many different plants, for example, in the form of alginate from algae and as psyllium in genus Plantago or in animals such as crustaceans in the form of chitin or better known as chitosan in its deacetylated form. Chemical structures of alginate, psyllium, and chitosan are shown in Figure 1. Both alginate and chitosan are reasonably well researched and already appear in many healthcare-related applications such as wound dressings. However, application of psyllium as a wound-healing agent is still required to be established [3]. Psyllium as an active ingredient has traditionally had a wide range of application in pharmaceutical industry and has often been used to treat constipation, diarrhea, high cholesterol, diabetes, and bowl inflammation as well as ulcerative colitis [4]. These health benefits of psyllium are partly due to its excellent gelling and subsequent high liquid absorption [6]. Psyllium is composed of a highly branched non-starch polysaccharide. The main chain contains (1→4) and (1→3) linkages comprising of xylopyranose residues, and the side chains are connected to the main chain through O-3 and/or O-2 linkages that comprise of single arabinofuranose and xylopyranose residues [3,5]. Figure 1.

Alginates, on the other hand, are natural linear polysaccharides derived from marine brown algae [6], and it is composed of two uronic acid monomers: mannuronic acid (M) and guluronic acid (G) [7 –9]. Alginates form hydrophilic gels based on their ability to exchange sodium ions present in the structure with calcium present in salty water [7,10]. Alginates with higher portion of the G component form much more rigid gels [11], whereas those with bigger portions of M component form much softer and more absorbent gels. The gelling ability of calcium alginate as fibers could be improved by introduction of excess sodium ions which ultimately increase water solubility of these fibers and make them gel more [1]. Gel formation within a dressing prevents wounds from getting dry thus accelerating the healing process as well as providing better cosmetic effects [10]. Alginates are biocompatible, hemostatic, and can be harmlessly absorbed by the body [11]. Wound dressings made from these materials are characterized by good permeability and gaseous exchanges imitating natural skin function, resulting in wound moisture management throughout the healing process [10,12].

Chitosan is also a polysaccharide material extracted from shells of crabs and lobsters; it is de-acetylated derivative of chitin [12,13]. Chitosan is a copolymer of β-(1→ 4)-2-amino-2-deoxy-d-glucopiranose and β-(1→4)-2-acetamido-2-deoxy-d-gluco- pyranose [13 –15]. It is a cationic bio-polymer with a broad spectrum of applications from biomedical to food and chemical industries. It is stated that low molecular weight chitosan, which can also be produced by acidic hydrolysis, can accelerate antibacterial, antifungal, and antitumor properties of chitosan [16,17]. Chitosan has found very useful applications in wound care due to its hemostatic, inherent antibacterial, and wound-healing properties. Bacteriostatic and fungistatic properties are of major importance in wound-care application. The bioactivity of chitosan is dependent on its ability to break down when exposed to lysozyme, the enzyme present in the body fluids. This process generates bioactive oligomers of N-acetylo-d-glucosoamine and d-glucosoamine, which facilitate wound granulation and accelerate the healing of wounds [10,18].

The present research work deals with the development and characterization of a chitosan coated psyllium-alginate fiber. It is quite difficult to produce these fibers from a single dope solution due to differences in their solubility; chitosan dissolves in organic or inorganic acid solution while alginate dissolves in water or aqueous alkali solutions [10]. Psyllium gelatinous mass is soluble in alkaline solution but becomes insoluble upon acidification [19]. Pure psyllium fibers are also very difficult to produce; therefore, blending of psyllium with alginate will be more effective and convenient method to combine these materials into a single product. It is, therefore, intended to develop a composite polysaccharides fiber with improved absorbency, antibacterial, good tensile strength, and wound-healing properties.

Materials and methods

Materials

Food grade Psyllium Husk (Marhaba Laboratories (Private) Ltd, Lahore, Pakistan) was purchased from a distributor. Sodium alginate (Portnal L/F 10/60), having high guluronic acid content (65–75%), was purchased from FMC biopolymer, Norway. Chitosan with a deacetylation degree (DDA) of ∼90–95% was purchased from Qingdao Yunzhou Biochemistry Co., Ltd, China. Analytical grade calcium chloride (CaCl₂) was purchased from RdH Laboratories GmbH & Co, Germany. Acetone (99%) was purchased from Merck, Germany. Laboratory grade sodium chloride was purchased from UNI-CHEM chemical reagents. Hydrochloric acid (HCl) 37% and acetic acid 100% were procured from RdH Laboratories GmbH & Co, Germany.

Psyllium gel extraction

To be able to utilize psyllium, it must first be extracted according to formulation described elsewhere [1]. Briefly, psyllium husk was dissolved in deionized water at room temperature of 22℃ at 65% Rh using a stirrer (HS 30D, Daihan, Korea) at 1500–2000 RPM for 2 h, then the resultant solution was filtered through a nylon mesh (250 µm) to remove the insoluble impurities.

Preparation of hydrolyzed chitosan solution

About 3000.0 ml of 1% v/v acetic acid solution was prepared using distilled water. Dry chitosan powder of 45.0 g (1.5% w/v) was added to 1% v/v acetic acid solution. The solution was then stirred for 2 h to yield a viscous solution. Hydrochloric acid of 3.5% v/v was then added to the solution under further stirring until homogeneity was obtained. The prepared solution was then heated under reflux for approximately 5 h, cooled overnight, and filtered (to remove any insoluble chitosan). The solution viscosity dropped from ∼50 cps to ∼12 cps and the pH of the solution remained unchanged before and after hydrolysis (i.e., 1.00).

Production of fiber

All fibers were produced using a multi-functional laboratory wet extruder locally designed and manufactured at National Textile University, Faisalabad, Pakistan, as illustrated in Figure 2. Dope solutions were poured into the dope tank and allowed to stay in the tank overnight to degas the dope solution. Afterwards, the dope was extruded into the coagulation bath and was drawn out of the coagulation bath by pick-up rollers. In the second bath, the fibers were drawn between the drawing rollers, by adjusting their RPM. In the third bath, these spun fibers were washed with distilled water to remove any traces of coagulation chemicals and finally wound up on a collecting roller.

Figure 2.

An illustration of multi-functional laboratory wet extruder.

Psyllium/alginate dope preparation

Three different combinations of dope solution of sodium alginate and psyllium were prepared for this research, these were the following: Dope 1 – sodium alginate (4% w/v) and psyllium (0.5% w/v), Dope 2 – sodium alginate (3.5% w/v) and psyllium (0.75% w/v), and Dope 3 – sodium alginate (3% w/v) and psyllium (1% w/v). All dope solutions were prepared in deionized water. The solutions were left in the tank overnight to degas and to remove air bubbles prior to extrusion. Control chitosan–alginate fiber was also produced.

Fiber extrusion

Prepared dope solutions were extruded by varying the order of coagulation baths. Method A, each dope solution was extruded into a bath containing 2.5% calcium chloride and directed into a bath containing 1.5% w/v hydrolyzed chitosan, followed by washing and drying; method B, each dope solution was extruded into bath containing 1.5% w/v hydrolyzed chitosan and directed into a bath containing 2.5% w/v calcium chloride, followed by washing and drying. Operating condition under which these fibers were produced is shown in Table 1. Control fiber (S7) was made by extruding 5% sodium alginate dope solution directly into 1.5% w/v hydrolyzed chitosan solution to make alginate–chitosan fiber and then directed into 2.5% w/v calcium chloride followed by washing and drying.

Table 1.

Operating conditions of chitosan–alginate and psyllium-containing chitosan–alginate fibers production.

Sample symbol	Dope solution concentration (%)
Sample symbol	Sodium alginate (%)	Psyllium (%)	Draw ratio (FR/BR)	First bath (coagulation bath)	Second bath
Fiber produced by method A
S1	4.0	0.5	1.4	2.5% CaCl₂	1.5% Hyd. Chitosan
S2	3.5	0.75	1.4	2.5% CaCl₂	1.5% Hyd. Chitosan
S3	3.0	1.0	1.4	2.5% CaCl₂	1.5% Hyd. Chitosan
Fiber produced by method B
S4	4.0	0.5	1.4	1.5% Hyd. Chitosan	2.5% CaCl₂
S5	3.5	0.75	1.4	1.5% Hyd. Chitosan	2.5% CaCl₂
S6	3.0	1.0	1.4	1.5% Hyd. Chitosan	2.5% CaCl₂
S7^a	5	0.0	1.4	1.5% Hyd. Chitosan	2.5% CaCl₂

^aControl fiber.

Absorbency measurement

Liquid absorption properties of all the developed fibers were tested using deionized water, saline (0.9% w/v NaCl), and solution A (0.83% w/v NaCl and 0.03% w/v CaCl₂). All samples were initially soaked for 1 h and hung in the air until no liquid droplets remained prior to taking measurements. Liquid absorption was calculated as the ratio of wet weight of the fibers to the weight of the fiber after drying overnight at 105℃. The absorption was calculated using the following equation:

Absorption (\frac{g}{g}) = \frac{W w - W d}{W d}

(1)

where W_d refers to the oven dry weight of fiber and W_w is the wet weight of fiber [1,2]. Ten readings of each fiber samples were taken and recorded as mean and standard deviation.

Swelling measurement

Swelling behavior or change in fiber diameter of the produced fibers was observed using a MICROS optical microscope (MC-50) with a digital camera. The change in diameter of the fibers soaked (for 4 min) in the above-mentioned solutions at 35℃ was recorded. Ten measurements were made and recorded as mean and standard deviation. The following equation was used to calculate % swelling:

% % swelling = \frac{D w - D d \times 100}{D d}

(2)

where D_w is the wet fiber diameter and D_d is dry fiber diameter [1,2].

Tensile properties

The tensile properties of the fibers were measured using fiber strength testing system M250-2.5CT (Testometric, Rochdale, England). Twenty test readings were taken, mean, and standard deviations were recorded. The test method employed was EN ISO 5079. The machine works on the principle of constant rate of extension (CRE). A single fiber was clamped between two points, one moveable and another fixed, 10 mm apart, and force applied was 10.0 N and set at 20 mm/min constant rate of extension.

Antibacterial testing

Antibacterial properties of all the samples were also measured according to the standard test method, AATCC 147-1998. A 10⁻⁵ dilution of overnight incubated strains of both Staphylococcus aureus and Escherichia coli were spread on the sterile agar plate. The test specimens were gently transversely placed against agar surface to ensure intimate contact. After incubation at 37℃ for 24 h, agar plates were examined for interruption of microbial growth underneath the specimen and for zone of inhibition along the edges of the specimen. The width of zone of inhibition was also calculated using the following equation:

W = \frac{(T - D)}{2}

(3)

where W is the width of clear zone of inhibition, T is the total diameter of test specimen and clear zone in mm, and D is the diameter of the test specimen in mm.

Scanning electron microscopy of fibers

Scanning electron microscopy (SEM) was used for morphological analysis of the fibers with Quanta 250 (FEI, USA) with an accelerating voltage of 15 kV and a magnification of 800×. Elemental analysis was carried out by energy dispersive spectroscopy (EDX) (INCA x-act, Oxford Instruments, UK) at 3 keV to measure the calcium contents of the control and composite fibers.

Fiber linear density

Linear densities of the fibers were determined by test method ASTM D 1059-12. Samples of 110 in. (2.8 m) length were prepared and weighed, using digital weighing balance. Linear density was calculated by using equation (4). Ten measurements were made; mean and standard deviation were recorded:

Tex = \frac{weightingrams (g)}{1000 m}

(4)

X-ray diffraction spectroscopy (XRD)

The wide-angle X-ray diffraction spectroscopy (WAXS) process was carried out on Xpert Pro diffractometer from PANalytical (USA) with Cu Kα radiation at a generator voltage of 40 kV and a generator current of 45 mA. The whole diffractogram analysis procedure was performed by using High Score Plus software. Crystallinity % was found by using the following equation:

Crystallinity % = \frac{Areaofcrystallinepeak X c}{Areaofcrystallinepeak X c + amorphouspeaks X a}

(5)

Crystallite size was measured by using the following Scherrer’s equation:

D = \frac{k λ}{β \cos θ}

(6)

Results and discussion

Linear density and tensile properties

Linear density and tensile properties of the produced and control fibers are given in Table 2. Linear density or mass per unit length of the two sets of fibers produced decreased with a decrease in the amount of alginate content. But the produced fibers by methods A and B exhibit higher linear density than the control chitosan–alginate fiber (S7). This increase in mass per unit length can be attributed to the inclusion of psyllium in the chitosan–alginate fiber. The potential interaction among the protonated hydrolyzed chitosan, psyllium, and deprotonated alginate chains is shown in Figure 3. The positively charged amino groups on the chitosan chain and calcium ions compete for binding with the alginates negatively charged carboxyl groups. The psyllium is mechanically entrapped between the hydrolyzed chitosan and alginate backbones.

Figure 3.

Potential interaction among the protonated-hydrolyzed chitosan, psyllium, and deprotonated alginate chains.

Table 2.

Fibers linear density and tensile properties.

Sample symbol	Linear density (tex)	St. dev.	Breaking force (cN)	St. dev.	Strain at rupture (%)	St. dev.	Tenacity (cN/tex)	St. dev.
Fiber produced by method A
S1	9.05	2.98	36.15	2.41	30.97	9.47	3.99	1.14
S2	8.62	3.39	38.79	2.93	40.15	19.68	4.50	0.87
S3	4.39	4.14	21.40	11.59	30.37	25.17	4.87	1.62
Fiber produced by method B
S4	14.78	3.62	125.46	1.38	34.65	19.33	8.48	1.66
S5	7.78	4.71	75.71	1.71	45.74	21.27	9.73	2.39
S6	7.12	2.12	183.31	13.31	31.09	14.61	25.75	9.91
S7	3.1	1.53	50.80	1.78	7.6	1.9	16.39	2.58

The fiber was produced by method B: first bath hydrolyzed chitosan and second bath CaCl₂; exhibit higher linear density than the fibers produced by method A: first bath CaCl₂ and second bath hydrolyzed chitosan. This behavior can be explained by the lower calcium content in the fibers produced by method B (Table 5) than in the first method and the same trend is reported by Sweeney et al. [2].

Table 5.

Calcium contents in chitosan–alginate and psyllium-containing chitosan–alginate fibers.

Sample symbol	Calcium (Ca) content weight (%)
Fiber produced by method A
S1	0.04
S2	0.03
S3	0.05
Fiber produced by method B
S4	0.01
S5	0.01
S6	0.02
S7	0.01

Tenacity of the produced fiber increased with the decrease in alginate content in both sets of fibers produced by methods A and B. As alginate content decreased, the calcium content in fibers increases (Table 5) which results in increased strength of the fiber due to greater calcium ion cross linking. However, the tenacity of the control fiber is higher than the produced fibers; this may be attributed to the strong ionic attractions between the NH₃⁺ of the chitosan and COO⁻ of the alginate polymer chains. Strain % of the produced fiber is higher than the control fiber (7.6%). The maximum values of strain % are shown by fiber-symbolled S2 and S5 (40.15 and 45.738%). This behavior of the produced fiber is not completely understood.

Swelling behavior

The developed fibers were tested for swelling behavior using the formulations given earlier (absorbency). Table 3 and Figure 4 demonstrate the swelling behavior of all the produced fibers against the control chitosan–alginate fiber. On an average, psyllium-containing chitosan–alginate fiber of 50–128% appear to be thicker than the control fiber, most probably due to the inclusion of psyllium. When soaked in distilled water, the control fiber swells up to 67.29%, while the other fibers showed a mixed behavior with maximum swelling of up to 131.45%. In saline solution, the swelling of the produced fibers was more than the control chitosan–alginate fibers. This is attributed to the combined action of the calcium/sodium ion exchange and the physical presence of psyllium, which naturally swells more with maximum swelling up to 369.3%. In solution A, the swelling is relatively lower than the saline solution, this may be due to the presence of calcium ions that are present in the solution A which hinders the ion exchange.

Figure 4.

% Swelling trend of chitosan–alginate and psyllium-containing chitosan-alginate fibers.

Table 3.

Percent swelling of chitosan–alginate and psyllium-containing chitosan–alginate fibers.

Sample symbol	D_d (µm)	D_w (µm)	D_s (µm)	D_a (µm)	D_w (%)	D_s (%)	D_a (%)
Fiber produced by method A
S1	96.08	190.50	275.23	140.58	99.74	188.68	47.73
S2	85.75	198.48	260.00	285.98	132.06	203.67	234.02
S3	90.73	103.03	376.08	107.28	13.63	314.87	18.32
Fiber produced by method B
S4	109.80	169.85	261.43	142.68	54.70	138.10	29.95
S5	73.50	98.60	351.00	132.50	34.15	377.47	80.36
S6	96.13	164.05	224.33	129.08	70.86	133.90	34.61
S7	48.065	80.408	103.32	63.129	67.29	114.57	31.34

D_d, dry fiber diameter; D_w, distilled water wet fiber diameter; D_s, saline water wet diameter; D_a, solution A wet fiber diameter.

Liquid absorption

Various liquid absorption results of chitosan–alginate fiber and psyllium-containing chitosan–alginate fibers are given in Table 4.

Table 4.

Liquid absorption of chitosan-alginate and psyllium-containing chitosan–alginate fibers.

Sample symbol	Distilled water (g/g)	St. dev.	0.9% Saline solution (g/g)	St. dev.	Solution A (g/g)	St. dev.
Fiber produced by method A
S1	16.96	0.32	28.05	0.71	22.27	0.39
S2	17.53	0.19	34.76	1.03	29.29	0.47
S3	19.38	0.46	25.20	0.56	21.17	0.91
Fiber produced by method B
S4	24.48	0.23	22.16	0.93	19.10	1.02
S5	24.28	0.72	26.31	0.78	23.81	0.81
S6	21.00	0.83	22.63	0.31	20.43	0.39
S7	21.02	0.22	20.03	0.98	20.81	0.35

Chitosan–alginate fibers have shown better water absorption in comparison with the psyllium-containing chitosan–alginate fibers developed by method A which may be attributed to lower amounts of Ca²⁺ ion present in the chitosan–alginate fiber. The calcium alginate fibers are insoluble in water and absorb lesser amount of water. Whereas the water absorption of the psyllium-containing chitosan–alginate fibers produced by method B have shown higher water absorption than chitosan–alginate fibers due to lesser presence of Ca²⁺ ions and easier accessibility of water molecules to highly absorbent psyllium present in the fibers. However, an increase in the psyllium concentration has shown no improvement in the water absorption of the produced fibers. But, it is quite different in the case of saline and solution A absorption. The fibers produced by method A, first passing through CaCl₂ bath, have shown better absorption. Calcium-containing alginates swell drastically and absorb larger amounts of liquid as they come in contact with sodium rich solutions.

The EDX analysis: the results of which are given in Table 5, the Ca content (weight %) of the control chitosan–alginate fiber and produced fibers obtained by energy dispersive spectroscopy (EDX). The data show that fibers produced by the first method have higher calcium % content in comparison with the control and the fibers produced by the second method.

Antibacterial activity

Chitosan is known to have effective antibacterial potency against a wide range of microbes. It is biologically compatible, has low noxiousness, excellent hemostatic activity and scar preventability as well as support in wound-healing process [18]. Gram-positive bacterium, S. aureus (ATCC 6538) and Gram-negative bacterium E. coli (ATCC 11230) were used in this study, as they are reported to be the major cause of hospital-acquired infections. Staphylococcus aureus is the most frequently evaluated bacteria in wound care practices. Skin tissue infections, septicemia, endocarditis, and staphylococcal meningitis [20] are normally caused by S. aureus. Whereas E. coli is mostly reported in urinary tract and gastrointestinal tract infections and accounts for more than 25% of human diseases [21].

Qualitative assessment of the microbial growth inhibition of the control chitosan–alginate fibers and produced fibers were carried out. The zone of inhibitions of different fibers was observed and the results are given in Table 6 and Figure 5. The maximum inhibition of 4.8 mm for S. aureus and 1.4 mm for E. coli was observed in the produced fibers. The inhibition zones for the control chitosan–alginate fibers were 4.4 mm for S. aureus and 0.7 mm for E. coli. The control and the produced fibers have shown better antibacterial activity against the S. aureus than against E. coli. It can be inferred from these results that inclusion of psyllium has no effect on antibacterial activity of the produced fibers.

Figure 5.

Antibacterial activity of chitosan-alginate and psyllium-containing chitosan–alginate fibers.

Table 6.

Antibacterial activity (zone of inhibition) of chitosan–alginate and psyllium-containing chitosan–alginate fibers.

Sample symbol	S. aureus (mm)	E. coli (mm)
Fiber produced by method A
S1	4.8	0.8
S2	4.6	0.5
S3	3.5	1.2
Fiber produced by method B
S4	2.2	0.3
S5	1	1.4
S6	3.8	1.2
S7	4.4	0.7

SEM analysis

The longitudinal view of the control fiber and fibers produced by method B is shown in Figure 6(a) and (c). It can be seen that the surfaces of the fibers are quite smooth and represents fairly even coating of chitosan on the surface of fiber. However, the fibers produced by method A have very irregular structure and can be seen in Figure 6(b).

Figure 6.

SEM images of (a) chitosan–alginate fiber, (b) psyllium-containing chitosan–alginate fiber (method A), and (c) psyllium-containing chitosan–alginate fiber (method B).

Serrations can be found on the surface of the fiber produced by method A (Figure 6(b)), this can be due to the fact that when dope solution is extruded directly in the coagulation bath containing calcium chloride, the fiber solidifies quickly and the hydrolyzed chitosan present in the second bath cannot uniformly cover the surface of the fiber and thus result in irregular fiber surface. However, by using method B, fibers have a more even surface covering of hydrolyzed chitosan on it and result in smoother fiber surface (Figure 6(a) and (c)). It appears that method of production and psyllium entrapments have a consequential influence on surface morphologies of these fibers.

XRD analysis

One crystalline (X_c) and one amorphous peak (X_a) were distinguished on the WAXS diffractograms of the sample S2 (method A) and sample S5 (method B) (Figure 7). Scherrer’s equation was used to find the true dimensions of the ordered crystalline regions in the fiber. It is evident from the results (Table 7) that fibers produced by method B (S5) are more crystalline than fibers produced by method A (S2). From which, we can correlate that strength of fibers produced by method B is more than fibers produced by method A. Similarly, the liquid absorption in fibers produced by method A is more than in fibers produced by method B.

Figure 7.

Comparison of WAXS diffractograms of S2 and S5 and alginate/chitosan/psyllium composite fibers.

Table 7.

Analysis of XRD diffractogram of alginate/chitosan/psyllium fibers obtained by WAXS method.

Sample symbol	Method of production	Fiber composition %			Area of peaks		Crystallinity %	Crystallite size, nm
Sample symbol	Method of production	Alginate	Psyllium	Chitosan	X _c	X _a	Crystallinity %	Crystallite size, nm
S2	Method A	3.5	0.75	1.5	121.30	55.66	68.54	29.2
S5	Method B	3.5	0.75	1.5	93.11	31.76	74.56	20.4

Conclusion

It is possible to produce homogeneous composite fibers of psyllium, alginate, and chitosan using two different extrusion routes. All these fibers have shown reasonable mechanical properties to be made into non-woven dressings for wound-care applications. Inclusion of psyllium resulted in enhanced swelling and gelation. Liquid absorption properties of the produced fibers are entirely dependent on the coagulation bath. Fibers directly extruded into CaCl₂-containing coagulation bath have shown lower water absorption than the fibers extruded directly into hydrolyzed chitosan bath. Saline and solution A absorption of the fiber directly extruded into CaCl₂ are better than fiber extruded directly into hydrolyzed chitosan bath. The psyllium inclusion has also improved the liquid absorption properties of the fibers. All fibers showed satisfactory antibacterial activity and inclusion of psyllium was shown to have no effect on the antibacterial properties of chitosan–alginate fibers. The study recommends the fiber extrusion by method A for wound-dressing applications as fibers produced by this method have adequate tensile strength, antibacterial ability, and have better absorption and swelling properties in the ions-rich solutions (saline and solution A) than fibers produced by method B.

Footnotes

Acknowledgement

The authors acknowledge the Higher Education Commission of Pakistan for funding this research study.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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