Claims:1. A method of fabricating a 3D printed human skin construct, the method comprising:
generating, by a computer (102), a 3-dimensional (3D) profile (208) of a human skin, wherein the 3D profile (208, 402) comprises:
a first set of layers, each layer of the first set having a plurality of linear filaments arranged in a grid-like periodic pattern, each adjacent pair of parallel filaments, of the plurality of linear filaments in the first set, being separated by a first inter-filament spacing;
a second set of layers on the first set of layers, each layer of the second set having a plurality of linear filaments arranged in a grid-like periodic pattern, each adjacent pair of parallel filaments, of the plurality of linear filaments in the second set, being separated by a second inter-filament spacing, the first inter-filament spacing being smaller than the second inter-filament spacing;
3D printing the 3D profile (208, 402) on a substrate using a first bio-ink composition to obtain a first portion of the 3D printed human skin construct, wherein the first portion resembles a dermis structure of the human skin; and
depositing a second bio-ink composition on the first portion to form a second portion of the 3D printed human skin construct, wherein the second portion resembles an epidermis structure of the human skin.

2. The method as claimed in claim 1, wherein the 3D profile (402) comprises a third set of layers on the second set of layers, each layer of the third set having a linear filament formed on a boundary on each side of the 3D profile (402).

3. The method as claimed in claim 1, wherein the first inter-filament spacing ranges from about 0.5 millimeters to about 0.8 millimeters and the second inter-filament spacing ranges from about 1 millimeter to about 2 millimeters.

4. The method as claimed in claim 1, wherein the generating is based on a plurality of 3D profile parameters indicative of dimensions of the 3D printed human skin construct, the plurality of 3D profile parameters comprising:
a length of the 3D printed human skin construct;
a breadth of the 3D printed human skin construct;
the first inter-filament spacing;
the second inter-filament spacing;
a thickness of each of the plurality of linear filaments in the first set;
a thickness of each of the plurality of linear filaments in the second set;
a number of layers in the first set; and
a number of layers in the second set.

5. The method as claimed in claim 1, wherein the 3D printing is based on a plurality of printing parameters indicative of printer settings of a 3D printer (104) used for the 3D printing, the plurality of printing parameters comprising:
a printer nozzle diameter for the 3D printing; and
an extrusion pressure at the printer nozzle for the 3D printing.

6. The method as claimed in claim 1, wherein the depositing comprises:
3D printing the second portion on the first portion using the second bio-ink composition, such that profile of the second portion is complimentary to, and fits with, the 3D profile (208, 402) of the first portion.

7. The method as claimed in claim 1, wherein the first bio-ink composition is a hydrogel composition comprising:
a silk-gelatin solution of a concentration ranging from about 5% by volume to about 15% by volume;
a silk fibroin solution of a concentration ranging from about 5% by volume to about 6% by volume;
a tyrosinase solution of a concentration ranging from about 100 International Unit (IU) to about 500 IU; and
human skin fibroblast cells with a cell count ranging from about 0.5 millions per ml to about 5 millions per ml.

8. The method as claimed in claim 1, wherein the second bio-ink composition is a hydrogel composition comprising:
a silk-gelatin solution of a concentration ranging from about 3% by volume to about 5% by volume;
a silk fibroin solution of a concentration ranging from about 5% by volume to about 20% by volume;
a tyrosinase solution of a concentration ranging from about 100 IU to about 500 IU;
human skin keratinocyte cells with a cell count ranging from about 0.5 millions per ml to about 5 millions per ml; and
human skin melanocyte cells with a cell count ranging from about 0.05 millions per ml to about 0.5 millions per ml.

9. The method as claimed in claim 1, further comprising:
maintaining the 3D printed human skin construct in a sterile environment within a laminar flow hood for a defined time period.

10. The method as claimed in claim 1, further comprising:
soaking the 3D printed human skin construct in a first liquid culture medium for a first time period in an incubator maintained at culture conditions;
after the soaking for the first time period, adding a second liquid culture medium to the 3D printed human skin construct;
after a second time period from addition of the second liquid culture medium, adding a third liquid culture medium to the 3D printed human skin construct;
after a third time period from addition of the third liquid culture medium, exposing the 3D printed human skin construct to an air-liquid interface formed at a contacting surface of a liquid culture media and the atmosphere inside the incubator, wherein the liquid culture media is a mixture of the first liquid culture medium, the second liquid culture medium, and the third liquid culture medium.

11. The method as claimed in claim 5, wherein the printer nozzle diameter ranges from about 50 micrometers to 260 micrometers and the extrusion pressure ranges from about 5 pounds per square inch to about 20 pounds per square inch.

12. The method as claimed in claim 10, wherein the first liquid culture medium is an epidermalization medium I, the second liquid culture medium is an epidermalization medium II, and the third liquid culture medium is a cornification medium.

13. A 3D printed human skin construct fabricated by the method as claimed in any of the claims 1 to 12.

14. A system for fabrication of a 3D printed human skin construct, the system comprising:
a computer (102) to generate a 3-dimensional (3D) profile (208, 402) of a human skin, wherein the 3D profile (208, 402) comprises:
a first set of layers, each layer of the first set having a plurality of linear filaments arranged in a grid-like periodic pattern, each adjacent pair of parallel filaments, of the plurality of linear filaments in the first set, being separated by a first inter-filament spacing;
a second set of layers on the first set of layers, each layer of the second set having a plurality of linear filaments arranged in a grid-like periodic pattern, each adjacent pair of parallel filaments, of the plurality of linear filaments in the second set, being separated by a second inter-filament spacing, the first inter-filament spacing being smaller than the second inter-filament spacing; a 3D printer (104) coupled to the computer (102) to:
print the 3D profile (208, 402) on a substrate using a first bio-ink composition to obtain a first portion of the 3D printed human skin construct, wherein the first portion resembles a dermis structure of the human skin; and
deposit a second bio-ink composition on the first portion to form a second portion of the 3D printed human skin construct, wherein the second portion resembles an epidermis structure of the human skin.

15. The system as claimed in claim 14, wherein the 3D profile (402) comprises a third set of layers on the second set of layers, each layer of the third set having a linear filament formed on a boundary on each side of the 3D profile (402).

16. The system as claimed in claim 14, wherein the first inter-filament spacing ranges from about 0.5 millimeters to about 0.8 millimeters and the second inter-filament spacing ranges from about 1 millimeter to about 2 millimeters.

17. The system as claimed in claim 14, wherein generation of the 3D profile (208, 402) is based on a plurality of 3D profile parameters indicative of dimensions of the 3D printed human skin construct, the plurality of 3D profile parameters comprising:
a length of the 3D printed human skin construct;
a breadth of the 3D printed human skin construct;
the first inter-filament spacing;
the second inter-filament spacing;
a thickness of each of the plurality of linear filaments in the first set;
a thickness of each of the plurality of linear filaments in the second set;
a number of layers in the first set; and
a number of layers in the second set.

18. The system as claimed in claim 14, wherein printing the 3D profile (208, 402) is based on a plurality of printing parameters indicative of printer settings of the 3D printer (104), the plurality of printing parameters comprising:
a printer nozzle diameter for the printing; and
an extrusion pressure at the printer nozzle for the printing.
, Description:As Attached