final dissertation ppt.

DEVELOPMENT OF CHITOSAN BASED ANTI-MICROBIAL LEATHER WITH

ENHANCED MECHANICAL PROPERTIES

Under the guidance of:Dr. R.K. Mishra

(Assistant Professor)&

Dr. Jaya Maitra (Co-Guidance)

Mechanical DepartmentSchool of Engineering

Gautam Buddha University,

Month-June-2016

M.Tech Dissertation Presentation End - SemesterBy- Shristi Sharma (11/IME/101)

OBJECTIVE

Our main objective is to make a natural composite out of goat leather and chitosan which has improved mechanical properties. Possesses anti-microbial activity and also the composite so made can be used in-vitro and in-vivo in humans as bio composite transplants.

INTRODUCTIONLEATHER- Leather is basically the Dermis layer of skin made up

of interwoven 3-D mesh of Collagen protein cemented by protein called Globulin.

Leather is known for its durability, high tensile strength, breathing capacity, flexibility, low at cost & maintenance, eco-friendly, insulates heat etc.

About 98.8 % of leather in the world comes from cow, sheep, pig and goat.

In developing countries goat leather is produced in maximum quantity.

Goat leather is chosen because:◦ More resilient leather found and has higher strength to

thickness ratio than cow or other type of easily available leathers.

◦ Is more suppler, durable and softer still possesses great flexibility than cow leather due to the presence of lanolin.

◦ The thickness of goat leather varies from 0.7 to 0.8 mm which is appropriate if used in tissue engineering.

CHITOSAN: Chitosan is a only known positively charged

polysaccharide which readily binds to negatively charged substances.

It is derived from treatment of chitin with alkaline NaOH found in the shells of crustaceans animals.

Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit).

Chitosan is used as various applications in medicinal field as it is hemostatic, anticholesteremic, antitumour, central nervous system depressant, fungistatic, immunoadjuvant, binds to human and microbial cells immediately and safe & non toxic.

Image source- Google

Development of Chitosan based Goat leather composite

1. Take 1.005 ml of 99.5% (v/v) acetic acid in 100 ml distilled water to make 1% or 1M acetic acid solution.

2. Preparation of 2% chitosan solution in 1% acetic acid solution.

3. Preparation of CaCl2 solutions of various molarities.4. Crosslink the chitosan solution and CaCl2 solutions by the

chosen procedure.5. Weigh 4 samples of leather of approximately (8±0.1) g to

make 0.5% chitosan leather composite (v/v).6. Spread the chitosan-CaCl2 cross linker solution by hand

layup method so made over the softer side of the leather evenly using a glass rod wetting all the surface area of the leather sample.

7. Leave the samples to dry at the ambient conditions for 2 days.

Sample composition Table

SampleChitosan soln.

(ml)

CaCl2 soln.

(ml)

Molarity of CaCl2

soln. (M)

Leather

weight (g)

I 25 25 0.005 8.09

II 25 25 0.02 8.05

III 25 25 0.035 8.01

IV 25 25 0.05 8.00

Table No.1

Mechanical Characterization Measurement of Thickness and Width Followed IS 5914-1970 from ASTM designation: D1516-60 using 0.5mm graduated vernier calliper.

Hardness Test Shore Durometer Model LX-A following the standards JB6148 is used .

Tensile Testing Followed the IS 5914-1970 and calculated the following parameters:

Tensile strength in MPa

Yield Strength in MPa

Young’s Modulus in MPa

Elongation (%).

Internal and Surface Morphology

1. The 1st specimen was of the pure leather sample without the matrix being applied.

2. The 2nd specimen was of the sample (IInd) which gave us the best results for tensile test on which chitosan – CaCl2 matrix was applied.

3. The 3rd specimen was taken of the sample which gave us the best results but at the site of fracture due to tensile test.

Biological Characterization Escherichia Coli Growth: Anti-microbial performance of the IInd sample was determined by using Escherichia Coli ATCC 10536. Agar Diffusion method is used in which a sample of 1cm x 1cm dimensions was moisturized by distilled water and kept in a colony of E.Coli (gram-negative bacteria) isolated on an agar petri plate for 1 week at 37˚C and pH 7.0 in Biochemical Oxygen Demand.

Invitro Degradation study: Performed by incubating IInd sample in two test tubes of 10mL of phosphate- buffered saline solution having a controlled pH of 7.4 in which first test tube contained lysozyme enzyme and second contained lipase enzyme. The two test tubes were agitated at 60rpm at 37˚C for 1week. Fluorescence spectroscopy is used to measure the degradation rate of the enzymes on the sample at 650 nm and 350nm respectively.

Water Absorption Test Performed by immersing the IInd sample in phosphate-buffered saline solution water at 37˚C for 24 hours.𝑊𝑎𝑡𝑒𝑟 𝐴𝑏𝑠𝑜𝑟𝑏𝑒𝑑 % = (𝑊𝑠− 𝑊𝑓)𝑊𝑓 ൨× 100 (1)

Where,

Ws- Swollen weight

Wf- Final dried weight

RESULTS

Mean thickness of the samples is 0.720mm. Mean width taken is 4mm. The hardness of the 4 samples is 2 BHN. The highest load at yield and the maximum load

were 43N and 53N faced by IInd sample. The maximum Yield strength and Tensile strength

obtained were 16MPa and 19 MPa.The maximum Young’s Modulus achieved

was 37 Mpa.The minimum elongation % is 78.896 % for

the IInd sample.

SAMPLE NO.

Young’s

Modulus (MPa)

I 16.167

II 36.553

III 22.186

IV 12.012 Sample I Sample II Sample III Sample IV0

5

10

15

20

25

Young's Modulus (Mpa)

SAMPLE NO.

Tensile Strength

(MPa)

I 7.186

II 19.491

III 9.965

IV 6.877

Validation of Tensile Test

•Leather density- 0.86 kg/m3•Poisons ratio of leather- 0.46•Young’s Modulus as 16.167 MPa, 36.553 MPa, 22.186 MPa and 12.012 MPa respectively for the four samples individually.

Sample No. Width(mm) Thickness(mm)

I 0.710 4

II 0.677 4

III 0.737 4

IV 0.757 4

Maximum stress obtained for Sample I

Maximum Stress obtained for Sample II

Maximum stress obtained for Sample III Maximum stress obtained for Sample IV

Comparison of the experimental analysis of maximum strength

with the Results over Ansys

SAMPLE

NO.

Results of

Strength (MPa)

of the

experimental

analysis

Results of

strength

over Ansys

I 7.186 7.45

II 19.491 19.5

III 9.965 10.79

IV 6.877 6.85

% Error obtained from the ANSYS analysis

Sample No. % Error

I 3.6%

II 0.41%

III 3.33%

IV 0.39%

Pure leather sample at 1010 X representing the interwoven structure of collagen fibres.

Invitro Study

SEM images of 2nd specimen (a) at 1040X magnification (b) at 1040X magnification (c) at 4110X magnification (d) at 9050X

magnification

SEM images (a) and (b) at 30440X and 30270X magnification showing the fibre being held by the matrix beads.

(a)

(b)

SEM image at the site of tensile test fracture (a) at 1000X magnification (b) at 1000X magnification (c) at 1040X magnification.

Escherichia Coli Growth/ Anti-microbial activity:

The IInd sample was kept in condition optimum for the growth of E.Coli for 1 week showed no growth over it.

Activity of enzymes:The bioactivity of lysozyme was determined by meaning of rate of lysozyme which was 200µg/mL and the bioactivity of lipase was 780µg/mL. These rates are similar to how lysozyme or lipase degrades any tissue in the human serum.

Water absorption test:We are focussing on the IInd sample the water absorptivity comes out to be 18 %.

CONCLUSION

1. The best results were obtained from the IInd sample that had the composition of 8g of leather, 25ml of chitosan solution (in 1% acetic acid solution) and 25ml of CaCl2 solution of 0.02M .

2. The maximum Yield strength and Tensile strength obtained were 16MPa and 19 MPa respectively which is around 300% more than a pure leather sample.

3. From the SEM images we conclude that the porosity of leather was decreased by the deposition and binding of the matrix with the leather giving it its extra amount of strength.

4. The IInd sample was kept in condition optimum for the growth of E.Coli for 1 week showed no growth over it. This shows it is anti-microbial also.

From all the above results we can conclude that we are able to make a composite which is made of naturally occurring materials, anti-microbial, has high strength, can be used as scaffolds in tissue engineering and can be made easily available in near future.

FUTURE SCOPE1. It can be used in making of anti-microbial possessing

high strength and durability leather products like shoes, bags, belts, wallets, dairy, book binding, jackets etc. also possessing the softness of goat leather too.

2. It can be applied to make antimicrobial high strength furniture and also as seat covers in high class luxury cars.

3. We can use my composite invitro to make scaffolds in tissue engineering to replace ruined skin around the ear, nose, fingers etc. that is especially extensors.

4. In future we can also use the composite in vivo to make different organ’s skin/covering by performing various tests.

THANK YOU