FIELD OF INVENTION
The present invention relates to the field of biological materials, and more
particularly to a freeze-dried powder of high molecular weight silk fibroin,
preparation process therefor and use thereof.
BACKGROUND OF THE INVENTION
In recent years, many biodegradable biological materials such as films, particles,
porous scaffolds and hydrogels, made of a regénerated silk fibroin solution, have
been shown to have excellent biocompatibility, non-immunogenicity and slow
degradation. They are becoming a new medical biological material, and can be
used as a product directly for clinical tissue repair or can be used as a carrier
support of drfigs and cells for sustained release of drugs and tissue engineering of
artificial organs. Therefore, a silk fibroin solution is a basis for preparing all silk
fibroin-based biological maierials, and how to obtain a silk fibroin solution with
high quality, high molecular weight, and high stability by purification is critical
for further development of silk fibroin-based medical biological materials.
Silk sericin is a natural polymer produced by silkworm, Bombyx mori, which
surrounds and keeps together two fibroin filaments in silk thread used in the
cocooh.
The recovery and reuse of sericin usually discarded by the textile industry not
only minimizes environmental issues but also has a high scientific and
commercial value.
~ The physicochemical properties of the molecule are responsible for numerous
applications in biomedicine and are influenced by the extraction method and
silkWorm lineage, which can lead to variations in molecular weight and amino
acid concentration of sericin.
The presence of highly hydrophobic amino acids and its antioxidant potential
make it possible for seric'm to be applied in the food and cosmetic industry.
The moisturizing power allows indications as a therapeutic agent for wound
healing, stimulating cell proliferation, protection against ultraviolet radiation, and
formulating creams and shampoos.
The antioxidant activity associated with low digestibility of sericin that expands
the application in the medical field, such as antitumour, antimicrobial and antiinflammatory
agent, anticoagulant, acts in colon health, improving constipation
and protects the body from obesity through improved plasma lipid profile.
In addition, the properties of sericin allow its application as a culture medium and
qryopreservation, in tissue engineering and for drug delivery, demonstrating its
effective use, as an important biomaterial.
OBJECTS OF THE INVENTION
The present invention is generally related to recovery of sericin from silk. The
present invention is particularly related to obtaining sericin by dcgumming liquor
to reduce the load in effluent. The present invention also helps in minimising the
environmental impact, and providing a biopolymer with numerous beneficial
qualities.
The recovery of sericin from degumming liquor can reduce the load in effluent,
minimising the environmental impact, and providing a biopolymer with numerous
beneficial qualities.
SUMMARY OF THE INVENTION
The present invention relates to Sericin is a natural, environmentally friendly,
proteinous, and biodegradable biopolymer derived as a waste product from the
silk industry. To provide raw silk sheen, ihe sticky sericin substance must be
removed during the degumming step. Sericin has a wide range of applications in
cosmetics, food, medicine, membranes, biomaterials, and omer sectors. As a
result, it is recovered as a by-product from silk waste using various extraction
processes. A thorough examination of the extraction circumstances is necessary
since they can influence the final qualities of sericin. Because sericin is particularly vulnerable to heat, the extraction conditions should be carefully
monitored. Hence, in this present investigation the SEM images of the RSS
powder obtained by freeze drying method compound shows the presence of
various particles in new shapes, siies and distributions of sericin freeze dried RSS
powders was studied using a scanning electron microscope in different
magnifications such as 30000X, 40000X, and 60000X. RSS powders is a
beneficial one in many aspects and also a biodegradable compound.
SUMMARY OF THE INVENTION
In order to solve the above technical problems, an object of the present invention
is to provide a preparation process of a freeze-dried powder of high molecular
weight silk fibroin, and this process realizes rapid preparation, high controllability
and reproducibility, as well as easy storage and transportation of freeze-dried
powder.

I/We claim,~
1. A preparation process of a freeze-dried powder of high molecular weight silk
fibroin, comprising the steps of:
'
a) boiling silk cocoons in 0.02 M sodium carbonate solution in a ratio of 10%
(w/v) till complete dissolution, followed by soakirig and washing with
clear water to get degummed silk;
b) dialyéing the degummed silk against deionized water for three days in a
dialysis tube;
c) centrifuging the degummed silk for 30 minutes at 9000 RPM afier
dialysis;
7
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d) afier determining the concentration of the solutioh, mixing the supernatant
with a buffer solution to prepai'e a silk fibro‘m’ solution, treating the silk
fibroin solution with high temperatfire and high pressure, maintaining the
molecular weight of the silk fibroin molecules, transferring a volume of
the silk fibroin solution into a container and
e) freeze-drying at -20'c to obtain the freeze-dried powder of high molecular
weight silk fibroin, followed by vacuqmizing for 48hIS and ice distillation,
to obtain macromolecule silk fibroin powder.