THESIS
2013
xxi, 134 pages : illustrations (some color) ; 30 cm
Abstract
Microspheres have been a growing field of study in the recent decades. Their small
homogeneous structure enabled them to be candidates in many nowadays micro-focused
applications including drug delivery, tissue imaging, bead-based assays, biosensors, etc. Apart
from their small size, they are also capable of carrying specific properties and functions to
accomplish different purposes. These parameters can be varied by making use for different
combinations of building materials and fabrication protocols.
This thesis presents a novel method for the production of microspheres composed of pure
proteins. Proteins are naturally available materials which has great plasticity. The proposed
approach aimed to fabricate protein microspheres which has adjustable physical properties
such as...[
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Microspheres have been a growing field of study in the recent decades. Their small
homogeneous structure enabled them to be candidates in many nowadays micro-focused
applications including drug delivery, tissue imaging, bead-based assays, biosensors, etc. Apart
from their small size, they are also capable of carrying specific properties and functions to
accomplish different purposes. These parameters can be varied by making use for different
combinations of building materials and fabrication protocols.
This thesis presents a novel method for the production of microspheres composed of pure
proteins. Proteins are naturally available materials which has great plasticity. The proposed
approach aimed to fabricate protein microspheres which has adjustable physical properties
such as size and porosity by changing the protocol parameters. Additional biological functions
can also be incorporated to the final product whenever necessary. This work also illustrates
their possible applications in both analytical and biomedical situations.
The protein microspheres successfully produced were characterized for their physical,
chemical and biological aspects. Their physical properties including morphology, size, and
porosity were done by electronic microscopes and particle analyzers. Their chemical
characteristics such as composition, surface charge, etc. were determined by various types of
spectroscopy. Their biological properties for example biocompatibility and biodegradability were tested by cell cultures, enzymatic treatments, etc. It was found that protein spheres with
size ranged from about 400 nm to 2000 nm could be mass produced (10
8 microspheres/mL)
within two hours. They composed of pure protein with natural properties preserved. They
were also harmless to cells and decomposable by enzymatic digestion. Upon successful
characterizations of the above properties, protein microspheres were tested for their practical
potentials in applying into bioanalytical and biomedical scenarios.
In analytical aspect, the microspheres were designed to carry an enzyme (horseradish
peroxidase) for colorimetric analyte detection. Due to the porous nature of microspheres, the
enzymatic products can be accumulated inside the cavity of microspheres for signal
amplification. Furthermore, fluorescent immunoassay was incorporated to form a dual
channel detection system. Both signals could be detected quantitatively for analysis.
In biomedical aspect, the drug delivery capability of the microspheres was revealed using
porcine ear as a skin model. The sizes of microspheres were customizable to a range that is
most favorable for penetration into the hair follicles. With the addition of massaging over the
skin, the microspheres were able to reach the bottom part of the hair follicles. We have
developed a two phase system to release the encapsulated content of microspheres in order to
achieve the drug delivery purpose. It was found that the released content was capable of going
inside the sebaceous gland.
The research results showed that protein microspheres can be prepared facilely without
sacrificing their native structure and functions. This will be an advantage for applying them
into real life situations where the action of proteins are necessary. This work opens more
opportunities in both basic and applied researches as the proposed protocol can act as a
platform to produce customizable protein microspheres for specific needs.
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