Surgical thread, cosmetic treatment and manufacturing method thereof
12053553 ยท 2024-08-06
Assignee
Inventors
Cpc classification
International classification
Abstract
The present invention provides a surgical thread, comprising a modified cross-section fiber, wherein the modified cross-section fiber is in a twisted state. The surgical thread of the present invention has advantages of good coefficient of kinetic friction, good tensile strength, good elongation rate and good softness, and good safety, comprising no inflammatory potential, no cytotoxicity, no pyrogen, no acute systemic toxicity and no intradermal irritation potential, and has the efficacy of promotion of collagen formation, thereby being suitable for embedding in the face. The present invention further provides a cosmetic treatment and a manufacturing method for the surgical thread.
Claims
1. A manufacturing method for a surgical thread, comprising: (1) a melt spinning step: melting a biodegradable material to obtain a thermoformed fiber by hot extrusion via a modified cross-section outlet, wherein the hot extrusion is processed at a temperature of 115? C. to 250? C.; cooling the thermoformed fiber to obtain a cooled fiber; and thermally drawing the cooled fiber to obtain a modified cross-section fiber; and (2) a twisting step: twisting the modified cross-section fiber lengthwise and further carrying out heat setting to obtain a semi-finished product; and cooling the semi-finished product to obtain the surgical thread, wherein the surgical thread comprises the modified cross-section fiber, and the modified cross-section fiber is in a twisted state.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(11) The present invention is further explained through the following embodiments. A person having ordinary skill in the art can easily understand the advantages and efficacies achieved by the present invention. The present invention should not be limited to the contents of the embodiments. A person having ordinary skill in the art can make some improvement or modifications which are not departing from the spirit and scope of the present invention to practice or apply the content of the present invention.
(1) Examples 1-1 to 4-1: The Surgical Thread
(12) Each example adopted a small melt spinning machine (Xplore?) for carrying out (1) a melt spinning step: melting a biodegradable material to obtain a thermoformed fiber by hot extrusion via a modified cross-section outlet, cooling the thermoformed fiber to obtain a cooled fiber; and thermally drawing the cooled fiber to obtain a modified cross-section fiber, which were the modified cross-section (cross-shaped) fibers 1-1 to 4-1; and (2) a twisting step: twisting the modified cross-section fiber (the modified cross-section (cross-shaped) fibers 1-1 to 4-1) lengthwise and further carrying out heat setting to obtain a semi-finished product; and cooling the semi-finished product to obtain the surgical thread, which were Examples 1-1 to 4-1; wherein the biodegradable material, the temperature of the hot extrusion (abbreviated as extruder temperature hereinafter), the rotation speed of the extruder screw, the temperature of the cooling for the thermoformed fiber, the winding speed and the spinning length for the cooled fiber, the temperature of the thermal drawing (abbreviated as thermal drawing temperature hereinafter), the amplification ratio of the thermal drawing (abbreviated as draw ratio hereinafter), the winding speed for the modified cross-section fiber, the amount of twist, the temperature of the heat setting, the time of the heat setting, the temperature of the cooling for the semi-finished product and the time of the cooling in each example were shown in Table 1.
(13) Further, for the biodegradable material of poly(L-lactide-co-caprolactone) (PLC), based on the total moles of L-lactide and caprolactone, L-lactide was in an amount of 65 molar percent to 75 molar percent, and caprolactone was in an amount of 25 molar percent to 35 molar percent; and for the biodegradable material of poly(glycolide-co-L-lactide) (PGL), based on the total moles of glycolide and L-lactide, glycolide was in an amount of 87 molar percent to 93 molar percent, and L-lactide was in an amount of 7 molar percent to 13 molar percent. Finally, the modified cross-section (cross-shaped) fibers 1-1 to 4-1 and Examples 1-1 to 4-1 each had a fiber outer diameter of 0.328 mm, and a fiber inner diameter of 0.1017 mm.
(14) TABLE-US-00001 TABLE 1 The name of the biodegradable material and the inherent viscosity thereof, the extruder temperature, the rotation speed of the extruder screw, the temperature of the cooling for the thermoformed fiber, the winding speed and the spinning length for the cooled fiber, the thermal drawing temperature, the draw ratio, the winding speed for the modified cross-section fiber, the amount of twist, the temperature of the heat setting, the time of the heat setting, the temperature of the cooling for the semi-finished product and the time of the cooling for Examples 1-1 to 4-1 Example Example Example Example 1-1 2-1 3-1 4-1 The Name PDO PLC PGL PLLA biodegradable The inherent 1.85 1.52 1.15 3.82 material viscosity (dL/g) The extruder temperature 205 125 208 205 (? C.) The rotation speed of the 15 15 15 15 extruder screw (RPM) The temperature of the 20 20 20 20 cooling for the thermoformed fiber (? C.) The cooled the winding 25 25 25 25 fiber speed (m/min) the spinning 80 80 80 80 length (cm) The thermal drawing 90 50 80 100 temperature (? C.) The draw ratio (times) 6 7 6 8 The winding speed for the 10 10 10 10 modified cross-section fiber (m/min) The amount of twist (TPM) 500 500 500 500 The temperature of the heat 90 50 80 100 setting (? C.) The time of the heat setting 5 5 5 5 (second) The temperature of the cooling 20 20 20 20 for the semi-finished product (? C.) The time of the cooling 10 10 10 10 (second)
(2) The Analysis for the Fiber Inner Diameter and the Fiber Outer Diameter of the Modified Cross-Section Fiber
(15) This analysis comprised three fibers of different sizes: two modified cross-section (cross-shaped) fibers 1-2 and 1-3 (untwisted) and one modified cross-section (Y-shaped) fibers 5-1 (untwisted). By measuring the target fiber in the photo, the fiber inner diameter and the fiber outer diameter thereof were obtained, and the results were shown in Table 2; wherein (1) the manufacturing methods of the modified cross-section (cross-shaped) fibers 1-2 and 1-3 were similar to that of the modified cross-section (cross-shaped) fiber 1-1, and the difference thereof was the lengths of the fiber outer diameter and the fiber inner diameter; (2) the manufacturing method of the modified cross-section (Y-shaped) fibers 5-1 was similar to that of the modified cross-section (cross-shaped) fiber 1-1, and the differences thereof were: (A) the shape of the modified cross-section outlet that the modified cross-section (Y-shaped) fiber 5-1 adopted a Y-shaped shape outlet, and (B) the lengths of the fiber outer diameter and the fiber inner diameter.
(16) TABLE-US-00002 TABLE 2 the measurement results of the fiber inner diameter, the fiber outer diameter and the ratio of the fiber inner diameter to the fiber outer diameter (abbreviated as the fiber inner/outer ratio hereinafter) of the modified cross-section fibers The modified cross- The modified cross- section (cross-shaped) section (Y-shaped) fibers (untwisted) fibers (untwisted) 1-2 1-3 5-1 The fiber 0.0921 0.1481 0.0655 inner diameter (mm) The fiber 0.2929 0.4852 0.1940 outer diameter (mm) The fiber 0.314 0.305 0.338 inner/outer ratio The photo FIG. 1A FIG. 1B FIG. 1C
(17) As shown in
(18) As shown in Table 2, the modified cross-section (cross-shaped) fibers 1-2 and 1-3 (untwisted) and the modified cross-section (Y-shaped) fibers 5-1 (untwisted) had a similar fiber inner/outer ratio. Therefore, the modified cross-section fiber of the present invention can adopt different sizes of the fiber inner diameter and the fiber outer diameter, and different shapes of the cross section to achieve a similar fiber inner/outer ratio, facilitating the subsequent twisting process and reserving a space for additional additives and the cell adhesions in the tissue.
(2) The Surface Analysis of the Modified Cross-Section Fiber and the Circular Cross-Section Fiber
(19) This analysis comprised the circular cross-section fiber 1-1 (untwisted) and the modified cross-section (cross-shaped) fiber 1-1 (untwisted); wherein the circular cross-section fiber 1-1 and the modified cross-section (cross-shaped) fibers 1-1 had the same fiber outer diameter, and the manufacturing method of the circular cross-section fiber 1-1 was similar to that of the modified cross-section (cross-shaped) fibers 1-1, wherein the difference was that the circular cross-section fiber 1-1 adopted a circular outlet.
(20) By measuring the perimeters of the cross sections of both fibers, the surfaces of both fibers were calculated and compared, wherein the perimeter of the circular cross-section fiber 1-1 served as the basis, which was indicated as 1, the results were shown in Table 3.
(21) TABLE-US-00003 TABLE 3 the perimeter ratios of the circular cross-section fiber 1-1 and the modified cross-section (cross-shaped) fibers 1-1 The circular The modified cross-section cross-section (cross-shaped) fibers 1-1 fiber 1-1 (untwisted) (untwisted) The perimeter 1 1.2113 ratio
(22) As shown in Table 3, the perimeter of the modified cross-section (cross-shaped) fibers 1-1 was about 1.2 times larger than that of the circular cross-section fiber 1-1. Therefore, if both fibers had the same total length, the surface of the modified cross-section (cross-shaped) fibers 1-1 would also be about 1.2 times larger than that of the circular cross-section fiber 1-1. In other words, when both fibers had the same fiber outer diameter, the modified cross-section (cross-shaped) fiber 1-1 of the present invention indeed increased the surface per unit length, thereby increasing the space for the cell adhesions in the tissue.
(3) Analysis of the Twisted States of the Modified Cross-Section Fiber
(23) This analysis comprised the modified cross-section (cross-shaped) fiber 6-1 (untwisted), and twisted modified cross-section (cross-shaped) fibers 6-1 to 6-5, which were Examples 6-1 to 6-5, and the structural differences were shown in Table 4; wherein the manufacturing method of the modified cross-section (cross-shaped) fiber 6-1 was similar to that of the modified cross-section (cross-shaped) fiber 1-1, wherein the difference was that the modified cross-section (cross-shaped) fiber 6-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2 approved by FDA; and the manufacturing methods of Examples 6-1 to 6-5 were similar to that of the modified cross-section (cross-shaped) fiber 1-1, wherein the differences were that (A) Examples 6-1 to 6-5 were further added with 0.1% (w/w) dye of D&C VIOLET NO. 2, and (B) Examples 6-1 to 6-5 had different twisted states. For clarification, D&C VIOLET NO. 2 provided colors to said fiber, thereby making said fiber more visible to facilitate carrying out the experiment, and had no impact on the analysis results.
(24) TABLE-US-00004 TABLE 4 the structural differences of the modified cross-section (cross- shaped) fibers 6-1 (untwisted) and Examples 6-1 to 6-5 The amount of twist Group The twist direction (TPM) The photo The modified N/A N/A FIG. 2A cross-section (cross-shaped) fiber 6-1 (untwisted) Example 6-1 Z-twist (clockwise) 500 FIG. 2B Example 6-2 S-twist 500 FIG. 2C (counterclockwise) Example 6-3 Z-S twist 500 for each FIG. 2D Example 6-4 Z-S-Z twist 500 for each N/A Example 6-5 S-Z-S twist 500 for each N/A
(25) As shown in
(26) Further, the schematic diagram of the structural differences of Examples 6-1 to 6-5 was shown in
(4) Analysis of the Coefficient of Kinetic Friction of the Surgical Threads
(27) This analysis comprised the circular cross-section fibers 1-1 to 3-1 and Examples 1-1 to 3-1; wherein the biodegradable materials of the circular cross-section fibers 1-1 to 3-1 corresponded to those of Examples 1-1 to 3-1 one by one, which were polydioxanone (PDO), poly(L-lactide-co-caprolactone) (PLC) and poly(glycolide-co-L-lactide) (PGL) in order.
(28) Further, the manufacturing methods of the circular cross-section fibers 1-1 to 3-1 were similar to those of Examples 1-1 to 3-1 one by one, wherein the differences were that: (A) the circular cross-section fibers 1-1 to 3-1 adopted a circular outlet; (B) the circular cross-section fibers 1-1 to 3-1 were not in a twisted state, as the circular cross-section fiber cannot be twisted to form a twisted state.
(29) The coefficient of kinetic frictions of the circular cross-section fibers 1-1 to 3-1 and Examples 1-1 to 3-1 were measured according to the international standard of ASTM D3108/D3108M-13 (Standard Test Method For Coefficient Of Friction, Yarn To Solid Material). By using the portable mechanical yarn friction tester purchased from Standard International Group (HK) Limited, the coefficient of kinetic frictions of the circular cross-section fibers 1-1 to 3-1 and Examples 1-1 to 3-1 were measured against the friction plate (a metal wheel) at a speed of 5 m/min.
(30) Further, the increase rate of the coefficient of kinetic frictions were respectively calculated according to the formula as follows: the increase rate of the coefficient of kinetic frictions=(the coefficient of kinetic friction of the Example?the coefficient of kinetic friction of the corresponding circular cross-section fiber)/the coefficient of kinetic friction of the corresponding circular cross-section fiber*100%. The results were shown in Table 5.
(31) TABLE-US-00005 TABLE 5 the coefficient of kinetic friction and the increase rate thereof of the circular cross-section fibers 1-1 to 3-1 and Examples 1-1 to 3-1 The coefficient of The increase rate kinetic friction of the coefficient Group The circular cross- of kinetic friction number section fiber Example (%) 1-1 0.34 0.43 26.5 2-1 0.34 0.42 23.5 3-1 0.28 0.36 28.6
(32) As shown in Table 5, when the biodegradable materials were chosen among PDO, PLC and PGL, the corresponding increase rates of the coefficient of kinetic friction were different. Further, Example 3-1, which adopted PGL, had the highest increase rate of the coefficient of kinetic friction of 28.6%. Nonetheless, as Example 3-1 had the coefficient of kinetic friction of 0.36, which was significantly lower than that of Example 1-1 of 0.43, PDO was the better choice for the biodegradable material.
(5) Analysis of the Tensile Strength, the Elongation Rate and the Density of the Surgical Threads
(33) This analysis comprised as follows:
(34) A. the circular cross-section fibers 1-1 to 3-1.
(35) B. Example 1-1, Example 1-2, and Examples 1-4 to 1-6, wherein all the biodegradable materials thereof were PDO, and the manufacturing methods of Example 1-2, and Examples 1-4 to 1-6 were similar to that of Example 1-1, wherein the difference was that both the fiber inner diameters and the fiber outer diameters of Example 1-1, Example 1-2, and Examples 1-4 to 1-6 were different.
(36) C. Examples 2-1 to 2-4, wherein all the biodegradable materials thereof were PLC, and the manufacturing methods of Examples 2-2 to 2-4 were similar to that of Example 2-1, wherein the difference was that both the fiber inner diameters and the fiber outer diameters of Examples 2-1 to 2-4 were different.
(37) D. Examples 3-1 to 3-5, wherein all the biodegradable materials thereof were PGL, and the manufacturing methods of Examples 3-2 to 3-5 were similar to that of Example 3-1, wherein the difference was that both the fiber inner diameters and the fiber outer diameters of Examples 3-1 to 3-5 were different.
(38) Finally, Example 1-1, Example 2-1 and Example 3-1, and the circular cross-section fibers 1-1 to 3-1 had the same fiber outer diameter.
(39) I. The Analysis of the Tensile Strength and the Elongation Rate:
(40) This analysis followed the standard of USP<881>tensile strength, and adopted the universal material testing machine purchased from MTS (US) to measure the tensile strength and the elongation rate simultaneously; wherein the thread of each group with the length of about 300 mm was clamped at its two ends by two clamps of the universal material testing machine. The distance between the two clamps was 150 mm, and the tensile strength and the elongation rate were measured simultaneously at a tensile speed of 300 mm/min.
(41) II. The Analysis of the Density:
(42) The weight of the thread of each group with a length of 300 mm was measured by a precision balance (brand: Mettler Toledo, model: Balance XPR204S) to obtain the weight per unit length of the thread of each group. Further, the fiber outer diameter of the thread of each group was measured by a thickness gauge for calculating the density of the thread of each group. Finally, the inner diameter of the thread of each group was measured by a microscope. The results were shown in Table 6.
(43) Besides, the specification in <USP 861> is as follows: A. 1: 0.400 mm to 0.499 mm. B. 0: 0.350 mm to 0.399 mm. C. 2-0: 0.300 mm to 0.349 mm. D. 3-0: 0.200 mm to 0.249 mm. E. 4-0: 0.150 mm to 0.199 mm. F. 5-0: 0.100 mm to 0.149 mm. G. 6-0: 0.070 mm to 0.099 mm. H. 7-0: 0.050 mm to 0.069 mm.
(44) For clarification, according to the standard of <USP 861>, 3-0 is 0.200 mm to 0.249 mm, not 0.200 mm to 0.299 mm. However, when the fiber outer diameter of the modified cross-section fiber is within 0.25 mm to 0.299 mm, such fiber outer diameter will still be classified as 3-0 in practice, as the mechanical strength thereof is inevitably weaker than that of the circular cross-section fiber with the same outer diameter.
(45) TABLE-US-00006 TABLE 6 the tensile strength, the elongation rate and the density of the circular cross-section fibers 1-1 to 3-1, Example 1-1, Example 1-2, Examples 1-4 to 1-6, Examples 2-1 to 2-4 and Examples 3-1 to 3-5 <USP 861> The fiber The fiber The tensile The The outer inner strength elongation density Group diameter diameter (N) rate (%) (g/cm.sup.3) The circular 2-0 N/A 30.45 ? 1.23 43.33 ? 2.38 1.256 cross-section fiber 1-1 Example 1-1 2-0 5-0 16.32 ? 0.78 45.24 ? 3.63 0.608 Example 1-2 3-0 6-0 9.77 ? 0.91 43.55 ? 4.01 0.608 Example 1-4 1 4-0 36.12 ? 1.97 47.31 ? 4.11 0.606 Example 1-5 0 5-0 23.15 ? 1.66 45.65 ? 3.98 0.607 Example 1-6 4-0 7-0 5.67 ? 0.63 42.18 ? 3.28 0.612 The circular 2-0 N/A 28.32 ? 1.16 52.12 ? 2.45 1.198 cross-section fiber 2-1 Example 2-1 2-0 5-0 10.78 ? 0.92 57.22 ? 4.26 0.578 Example 2-2 0 5-0 20.15 ? 1.89 59.45 ? 4.71 0.572 Example 2-3 3-0 6-0 7.02 ? 0.64 57.67 ? 4.02 0.581 Example 2-4 4-0 7-0 3.03 ? 0.41 56.47 ? 4.19 0.583 The circular 2-0 N/A 29.87 ? 1.92 48.41 ? 2.92 1.432 cross-section fiber 3-1 Example 3-1 2-0 5-0 14.32 ? 0.85 50.21 ? 3.85 0.618 Example 3-2 1 4-0 33.92 ? 2.32 53.25 ? 3.32 0.616 Example 3-3 0 5-0 22.15 ? 1.89 51.15 ? 3.89 0.617 Example 3-4 3-0 6-0 8.88 ? 0.65 49.67 ? 2.85 0.619 Example 3-5 4-0 7-0 4.84 ? 0.32 48.33 ? 2.77 0.621
(46) From the comparison of the circular cross-section fiber 1-1 and Example 1-1, under the condition of the same fiber outer diameter, Example 1-1 had the tensile strength of 16.32 N, which was significantly lower than 30.45 N of the circular cross-section fiber 1-1; and Example 1-1 had the density of 0.608 g/cm.sup.3, which was significantly lower than 1.256 g/cm.sup.3 of the circular cross-section fiber 1-1. However, under the condition that the fiber inner diameter of the surgical thread of the present invention is the same as the fiber outer diameter, which is the diameter of the cross section of the circular shape, of the circular cross-section fiber, the surgical thread of the present invention is estimated to have a higher tensile strength than that of a circular cross-section fiber.
(47) Further, from the comparison of Example 1-1, Example 2-1 and Example 3-1, under the condition that all groups had the same lengths of the fiber outer diameter and the same fiber inner diameter, Example 1-1, which adopted PDO, had the highest tensile strength of 16.32 N, which was higher than (1) 10.78 N of Example 2-1, which adopted PLC; and (2) 14.32 N of Example 3-1, which adopted PGL.
(48) Further, Example 2-1, which adopted PLC, had the highest elongation rate of 57.22%; and Example 3-1, which adopted PGL, had the highest density of 0.618 g/cm.sup.3.
(6) The Cell Adhesion Experiment for the Comparison of the Shape of the Cross Section of the Fibers
(49) This experiment comprised 4 groups: the circular cross-section fiber 6-1 (untwisted), the modified cross-section (cross-shaped) fiber 6-1 (untwisted), the circular cross-section fiber 7-1 (untwisted) and modified cross-section (cross-shaped) fiber 7-1 (untwisted).
(50) A. the circular cross-section fiber 6-1 (untwisted) and the modified cross-section (cross-shaped) fiber 6-1 (untwisted); wherein (A1) the manufacturing method of the circular cross-section fiber 6-1 (untwisted) was similar to that of the modified cross-section (cross-shaped) fiber 1-1, and the differences were that: I. the circular cross-section fiber 6-1 (untwisted) adopted a circular outlet; and II. the circular cross-section fiber 6-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2; and (A2) the manufacturing method of the modified cross-section (cross-shaped) fiber 6-1 (untwisted) was similar to that of the modified cross-section (cross-shaped) fiber 1-1, and the difference was that the modified cross-section (cross-shaped) fibers 6-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2.
(51) Further, both the circular cross-section fiber 6-1 (untwisted) and the modified cross-section (cross-shaped) fiber 6-1 (untwisted) had the same biodegradable material of PDO and the same fiber outer diameter; wherein the difference thereof was the shape of cross section of the fibers.
(52) B. the circular cross-section fiber 7-1 (untwisted) and modified cross-section (cross-shaped) fiber 7-1 (untwisted); wherein (B1) the manufacturing method of the circular cross-section fiber 7-1 (untwisted) was similar to that of the modified cross-section (cross-shaped) fiber 2-1, and the differences were that: I. the circular cross-section fiber 7-1 (untwisted) adopted a circular outlet; and II. the circular cross-section fiber 7-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2; and (B2) the manufacturing method of the modified cross-section (cross-shaped) fibers 7-1 (untwisted) was similar to that of the modified cross-section (cross-shaped) fiber 2-1, and the difference was that the modified cross-section (cross-shaped) fibers 7-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2.
(53) Further, both the circular cross-section fiber 7-1 (untwisted) and the modified cross-section (cross-shaped) fiber 7-1 (untwisted) had the same biodegradable material of PLC and the same fiber outer diameter; wherein the difference thereof was the shape of cross section of the fibers.
(54) This experiment comprised the following steps:
(55) The mouse fibroblasts (L929 cell line, 5?10.sup.4 cells per well) were seeded into a 24-well culture plate for each group; wherein said each group was added with a respective one of said fibers, which all had the same fiber outer diameters, in an amount of 0.01 g, and cultured at 37? C. in ?-MEM medium supplemented with 10% horse serum. For clarification, 0.01 g of said fiber can surround a single hole of the 24-well culture plate several times, and was long enough for analysis.
(56) The fibers in each group were taken out after 1, 3, 5 and 7 days of culture, and analyzed by the MTS cell activity analysis kit, and the absorbance at 490 nm for each group was measured by a spectrophotometer to evaluate the cell proliferation of the mouse fibroblasts in each group. As the mouse fibroblasts nearly reached full confluence and nearly covered all the surface of said fiber after 5 days of culture, the absorbance at 490 nm for each group after the 5 days of culture was chosen for comparison; wherein the cell proliferation amount of the circular cross-section fiber 6-1 (untwisted) served as the basis and was indicated as 1 for the comparison with that of the modified cross-section (cross-shaped) fibers 6-1 (untwisted); and the cell proliferation amount of the circular cross-section fiber 7-1 (untwisted) served as the basis and was indicated as 1 for the comparison with that of the modified cross-section (cross-shaped) fibers 7-1 (untwisted). The results were shown in
(57) As shown in
(58) Further, while the surface of the modified cross-section (cross-shaped) fibers 6-1 (untwisted) was about 1.2 times larger than that of the circular cross-section fiber 6-1 (untwisted), and the cell proliferation amount of the modified cross-section (cross-shaped) fibers 6-1 was about 3 times higher than that of the circular cross-section fiber 6-1 (untwisted). Therefore, the modified cross-section fiber of the present invention can achieve unexpected efficacy of cell adhesion improvement.
(7) The Cell Adhesion Experiment for the Comparison of the Twisted/Untwisted State of the Fibers
(59) This experiment comprised 3 groups: the circular cross-section fiber 7-1 (untwisted), the modified cross-section (cross-shaped) fibers 7-1 (untwisted) and the twisted modified cross-section (cross-shaped) fibers 7-1 (Example 7-1); wherein all said three fibers had the same biodegradable materials of PLC, and the same fiber outer diameter.
(60) As mentioned above, the manufacturing method of the circular cross-section fiber 7-1 (untwisted) was similar to that of the modified cross-section (cross-shaped) fiber 2-1, and the differences were that: I. the circular cross-section fiber 7-1 (untwisted) adopted a circular outlet; and II. the circular cross-section fiber 7-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2.
(61) As mentioned above, the manufacturing method of the modified cross-section (cross-shaped) fiber 7-1 (untwisted) was similar to that of the modified cross-section (cross-shaped) fiber 2-1, and the difference was that the modified cross-section (cross-shaped) fibers 7-1 (untwisted) was further added with 0.1% (w/w) dye of D&C VIOLET NO. 2.
(62) The manufacturing method of the twisted modified cross-section (cross-shaped) fiber 7-1 (Example 7-1) was similar to that of Example 2-1, and the difference was that Example 7-1 was further added with 0.10% (w/w) dye of D&C VIOLET NO. 2.
(63) This experiment comprised the same step as that in (6) the cell adhesion experiment for the comparison of the shape of the cross section of the fibers; wherein the cell proliferation amount of the circular cross-section fiber 7-1 (untwisted) served as the basis and was indicated as 1 for the comparison of the cell proliferation amount. The results were shown in
(64) As shown in
(65) Further, the space available for cell adhesion of Example 7-1 should be smaller than or equal to that of the modified cross-section (cross-shaped) fibers 7-1 (untwisted). As the cell proliferation amount of Example 7-1 was still higher, the twisted state can achieve unexpected efficacy of cell adhesion improvement.
(8) The Subcutaneous Implantation Study
(66) This study comprised: the twisted modified cross-section (cross-shaped) fiber: Example 2-5, which was shown in
(67) This study was carried out according to ISO 10993-6:2016 (Biological evaluation of medical devicesPart 6: Tests for local effects after implantation.) The experimental animals were two New Zealand White Rabbits in total, and were raised individually in separate cages during the experiment. The temperature of the environment was 19?3? C.; the humidity was 50?20%; and the light cycle was 12 hours light and 12 hours dark. The name of the feed is Prolab Rabbit Diet (brand: LabDiet, US), and the drinking water is RO water, both of which were supplied ad libitum.
(68) Example 2-5 was implanted into the subcutaneous site on the left side of the back of the two experimental animals, as shown and pointed out by the arrows in
(69) After Example 2-5 and Comparative Example 1 were implanted for 28 days, the experimental animals were sacrificed, and the tissue samples at the implantation sites were collected, fixed, and preserved in 10% neutral buffered formalin for the subsequent hematoxylin and eosin stain and microscopic examination. The results were shown in
(70) According to the histopathology evaluation format in ISO 10993-6:2016, the score for the inflammation indicators (polymorphonuclear, lymphocytes, plasma cells, macrophages, giant cells, necrosis), neovascularisation, fibrosis, fatty infiltrate, traumatic necrosis and foreign body debris were provided in order, and the results were shown in Table 7; wherein the SUB-TOTAL indicated sum of score among groups; and the Average indicated sum of score among groups/the numbers of recognizable implantation sites, which was used to determine irritant ranking in the conclusion of the histopathological evaluation, and a negative difference was recorded as zero.
(71) TABLE-US-00007 TABLE 7 the evaluation results of polymorphonuclear, lymphocytes, plasma cells, macrophages, giant cells, necrosis, neovascularisation, fibrosis, fatty infiltrate, traumatic necrosis and foreign body debris of Example 2-5 and Comparative Example 1 Comparative Implantation site Example 2-5 Example 1 number T1 T2 C1 C2 Inflammation score Polymorphonuclear 1 1 1 1 Lymphocyte 1 1 2 2 Plasma cells 0 0 0 0 Macrophage 1 1 1 1 Giant cells 0 0 0 0 Necrosis 0 0 0 0 SUB-TOTAL (x2) 12 16 Neovascularisation 1 1 1 1 Fibrosis 1 1 2 2 Fatty infiltrate 0 0 0 0 SUB-TOTAL 4 6 TOTAL 16 22 GROUP TOTAL 16 22 Average 8.0-11.0 = ?3.0 Traumatic necrosis 0 0 0 0 Foreign body 0 0 0 0 debris Conclusion minimal or no reaction (0.0 to 2.9)
(72) As shown in Table 7, Example 2-5 had a score of lymphocyte of 2 in total, which was lower than that of 4 of Comparative Example 1. Therefore, Example 2-5 had a lower inflammatory potential. Further, Example 2-5 had a score of fibrosis of 2 in total, which was lower than that of 4 of Comparative Example 1. Therefore, Example 2-5 had lower risk of incurring subcutaneous tissue fibrosis.
(73) Further, the group total of Example 2-5 was 16, so the average thereof was 8; and the group total of Comparative Example 1 was 22, so the average thereof was 11. As the average of Example 2-5 was lower than that of Comparative Example 1, a negative difference was obtained and recorded as zero. Therefore, among the four irritant rankings: (1) minimal or no reaction (0,0 to 2,9); (2) slight reaction (3,0 to 8,9); (3) moderate reaction (9,0 to 15,0); and (4) severe reaction (15,1), Example 2-5 had the lowest irritant ranking: minimal or no reaction.
(74) Further, as shown in
(75) Finally,
(9) Cytotoxicity Test
(76) This test comprised: the original extract of Example 2-5 (Example 2-6), the 50% extract of Example 2-5 (Example 2-7), the original extract of Comparative Example 1 (Comparative Example 2), the blank, the negative control and the positive control, and followed ISO 10993-5:2009 (Biological evaluation of medical devices) and EN ISO 10993-5:2009 to carry out the cytotoxicity test for the extracts of Example 2-5 and Comparative Example 1 (Example 2-6, Example 2-7 and Comparative Example 2).
(77) A. The Preparation of the Extracts:
(78) I. Example 2-6, Example 2-7 and Comparative Example 2: According to the standard of ISO 10993-12:2021, the extraction ratio of the test article (Example 2-5 and Comparative Example 1) was that the surface of the test article/the volume of the culture medium shall be about 6 cm.sup.2/mL, and the incubation was carried out at a rotation speed of 100 rpm under 37?1? C. for 24?2 h for extraction. After extraction, the original extracts of Example 2-5 and Comparative Example 1 were clear, particulate-free and without color change. Example 2-7 was obtained by doubling the culture medium of Example 2-6. Further, the culture medium was MEM alpha which comprised 10% (v/v) horse serum, 1% (v/v) penicillin-streptomycin solution, 1% (v/v) L-glutamine and 1% (v/v) non-essential amino acids.
(79) II. The extracts of the blank, the negative control and the positive control: (1) the blank was obtained by incubating 5.0 mL of the culture medium at a rotation speed of 100 rpm under 37?1? C. for 24?2 h; (2) the negative control adopted high density polyethylene (HDPE). According to ISO 10993-12:2021, the ratio (the weight of the test article (HDPE)/the volume of the culture medium) was about 0.2 g/mL, so 1 g of HDPE was immersed in 5 mL of the culture medium, and incubated at a rotation speed of 100 rpm under 37?1? C. for 24?2 h; and (3) the positive control adopted Dimethyl sulfoxide (DMSO), and based on the total volume of DMSO and the culture medium, the concentration of DMSO was 10% (v/v). The culture medium with 10% (v/v) DMSO was incubated at a rotation speed of 100 rpm under 37?1? C. for 24?2 h.
(80) B. Quantitative Analysis of Toxicity:
(81) 1?10.sup.4 of L929 mouse fibroblast cells were seeded in 96-well culture plates, and then incubated in the culture medium of MEM alpha at 37?1? C. in 5% CO.sub.2 atmosphere for 24?2 h. Afterwards, the culture medium of MEM alpha in each well was removed and replenished with 0.5 mL of the corresponding extract of each group, wherein each group was carried out in triplicate, and subsequently incubated at 37?1? C. in 5% CO.sub.2 atmosphere for 24?2 h. At the end of the incubation period, the extracts of each group were removed and replenished 0.1 mL of fresh culture medium in each well. 10 ?L MTT reagent (kit component, 4890-25-01) was further added into each well. The reaction was performed at 37? C. in 5% CO.sub.2 atmosphere for 2 hours to 3 hours and kept from light, and then 0.1 mL of detergent reagent (kit component, 4890-25-02) was added into each well for further incubation in dark for 2 hours to 3 hours. Finally, the absorbance of each group was measured at 570 nm by a microplate reader (ELx800, BioTek); wherein the absorbance of the blank served as the basis for cell viability, which was provided as 100%. The results were shown in Table 8; wherein a cell viability <70% indicated that the group had a cytotoxic potential.
(82) TABLE-US-00008 TABLE 8 the viabilities and mortalities of cells of the blank, the negative control, the positive control, Example 2-6, Example 2-7 and Comparative Example 2 Group Absorbance (OD.sub.570 nm) Viability (%) Mortality (%) Blank 1.160 ? 0.005 100 0 Negative control 1.039 ? 0.030 90 10 Positive control 0.198 ? 0.001 17 83 Example 2-6 1.063 ? 0.021 92 8 Example 2-7 1.088 ? 0.027 94 6 Comparative 0.770 ? 0.021 74 26 Example 2
(83) As shown in Table 8, the cell viabilities of Example 2-6 and Example 2-7 were 92% and 94%, respectively, which were more than 70%, and indicated as no cytotoxicity according to ISO 10993-5:2009. Further, the cell viability of Example 2-6 of 92% was significantly higher than 74% of Comparative Example 2. Therefore, the surgical thread of the present invention had a higher safety than the commercial surgical threads for embedding.
(84) C. Qualitative Analysis of Toxicity:
(85) This analysis comprised the blank, the negative control, the positive control, Example 2-6 and Comparative Example 2. For clarification, according to the results of the quantitative analysis of toxicity, Example 2-6 was safe, so Example 2-7 was not included in this analysis. This analysis comprised the steps as follows: 5?10.sup.4 of L929 mouse fibroblast cells were seeded in 24-well culture plates, and then incubated in the culture medium of MEM alpha at 37?1? C. in 5% CO.sub.2 atmosphere for 24?2 h. After cell adhesion was in a sub-confluent monolayer, the culture medium of MEM alpha in each well was removed and replenished with 0.5 mL of the corresponding extract of each group, wherein each group was carried out in triplicate, and subsequently incubated at 37?1? C. in 5% CO.sub.2 atmosphere for 24?2 h. At the end of the incubation period, the cells in each group were stained with the neutral red solution, and the cell morphology was observed under an inverted microscope. The results were shown in
(86) As shown in
(10) Pyrogen Study
(87) This study was carried out according to USP 45/NF40:2022<151> and ISO/TR 21582:2021. The experimental animals were three male New Zealand White Rabbits, so this study was carried out in triplicate, and the original extract of Example 2-5 (Example 2-8) was injected intravenously into the ear vein of each rabbit with a single dose of 10 ml/kg.
(88) Example 2-8: according to ISO 10993-12:2021, the ratio (the surface of the test article (Example 2-5)/the volume of saline) was about 6 cm.sup.2/mL, and Example 2-5 was immersed in saline, and incubated at a rotation speed of 100 rpm under 50?2? C. for 72?2 h for extraction. After extraction, the original extract of Example 2-5 (Example 2-8) was clear, particulate-free and without color change.
(89) The body weight of each experimental animal was measured before the injection of Example 2-8 to determine the injection volume, and the body temperature of each experimental animal was also measured and served as the basis. Further, the body temperatures thereof were measured at 1 hour, 1.5 hours, 2 hours, 2.5 hours and 3 hours after the injection of Example 2-8.
(90) The result was that the body temperatures of the three male New Zealand white rabbits increased by 0.21? C., 0.11? C. and 0.24? C. respectively. As such temperature change was lower than 0.5? C., Example 2-8 passed the pyrogen test according to USP 45/NF40:2022<151> or ISO/TR 21582:2021, which indicated that the surgical thread of Example 2-5 did not have pyrogens.
(11) Acute Systemic Toxicity Study
(91) This study was carried out according to ISO 10993-11:2017. The experimental animals were male ICR mice, and this study comprised four groups: (1) the control group with a polar vehicle: Intravenous injection (IV. injection) of saline; (2) the experimental group with a polar vehicle: I.V. injection of the original extract of Example 2-5 (Example 2-9) obtained by immersing Example 2-5 in saline; (3) the control group with a non-polar vehicle: intraperitoneal injection (IP. injection) of cottonseed oil; and (4) the experimental group with a non-polar vehicle: I.P. injection of the original extract of Example 2-5 (Example 2-10) obtained by immersing Example 2-5 in cottonseed oil.
(92) Example 2-9: According to ISO 10993-12:2021, the ratio (the surface of the test article (Example 2-5)/the volume of saline) was about 6 cm.sup.2/mL, and Example 2-5 was immersed in saline, and incubated at a rotation speed of 100 rpm under 50?2? C. for 72?2 h for extraction. After extraction, the original extract of Example 2-5 (Example 2-9) was clear, particulate-free and without color change.
(93) Example 2-10: According to ISO 10993-12:2021, the ratio (the surface of the test article (Example 2-5)/the volume of cottonseed oil) was about 6 cm.sup.2/mL, and Example 2-5 was immersed in cottonseed oil, and incubated at a rotation speed of 100 rpm under 50?2? C. for 72?2 h for extraction. After extraction, the original extract of Example 2-5 (Example 2-10) was clear, particulate-free and without color change.
(94) Each group had five experimental animals, and each experimental animal was injected with a single dose of 50 ml/kg. All experimental animals were observed for the determination of toxicity reaction or death immediately after injection and at 4.sup.th, 24.sup.th, 48.sup.th and 72.sup.nd hour after injection. The results showed that no toxicity reaction or death was observed in all groups, so Example 2-9 and Example 2-10 passed acute systemic toxicity study, which indicated that the surgical thread of Example 2-5 had no acute systemic toxicity.
(12) Intracutaneous Irritation Study
(95) This study was carried out according to ISO 10993-23:2021 (Part 23: Biological evaluation of medical devices Tests for irritation). The experimental animals were male New Zealand White Rabbits, and this study comprised four groups: (1) the control group with a polar vehicle: Injection of saline on the back of the experimental animal; (2) the experimental group with a polar vehicle: Injection of the original extract of Example 2-5 (Example 2-11) obtained by immersing Example 2-5 in saline on the back of the experimental animal; (3) the control group with a non-polar vehicle: Injection of cottonseed oil on the back of the experimental animal; and (4) the experimental group with a non-polar vehicle: Injection of the original extract of Example 2-5 (Example 2-12) obtained by immersing Example 2-5 in cottonseed oil on the back of the experimental animal; wherein Example 2-11 was the same as Example 2-9, and Example 2-12 was the same as Example 2-10.
(96) Each group was injected with a single dose of 0.2 ml for one injection site, and there were five injection sites for each group. All experimental animals were observed for the determination of intracutaneous/intradermal reaction immediately after injection and at 24.sup.th, 48.sup.th and 72.sup.nd hour after injection. The photos of the results at 24.sup.th, 48.sup.th and 72.sup.nd hour after injection were shown in
(97) To sum up, the surgical thread of the present invention has the following advantages: (1) increasing the surface, thereby reserving a space for additional additives and the cell adhesions in the tissue; (2) increasing the coefficient of kinetic friction for adhering to or staying in the tissue for a longer period, thereby enhancing the cosmetic efficacy; (3) reducing the weight burden on the face of the patients after the implantation of the surgical thread; (4) increasing the softness of the surgical thread, thereby increasing the popularity in clinical applications; (5) improving cell adhesion and proliferation; (6) promotion of collagen formation, thereby improving the elasticity and firmness of the skin; (7) good safety, comprising: no inflammatory potential, no cytotoxicity, no pyrogen, no acute systemic toxicity and no intradermal irritation potential.