RMT2002 Material Sciences In Biological Applications
Introduction to Biomaterials
Materials science = a study of solid functional materials
- Progress in materials science is often driven by the requirements for new
technology. On the other hand, advances in materials science often result in
associated advances in technology.
Biomaterials specifically refers to the development and application of materials in a
biomedical context.
Biomaterials are used to make artificial ECM!
3 main types of materials
1. Metals (metallic bond = keeps atoms together, conduct electricity ; electrons can
move)
2. Ceramics (brittle ; break very easily, ionic bond)
3. Polymers (long molecules, repeating units of monomers, functional groups ;
specific properties)
Chemical bonds
- Ionic bonds (NaCl): Ionic bonds are formed when two atoms exchange electrons
to create a positive and negative ion.
- Covalent bonds (H2O): Covalent bonds are formed when atoms share electrons
to create a molecule.
- Metallic bonds: Metallic bonds are created when metal atoms lose their
outermost electron to form positively charged ions.
Types of Atoms Type of Bond Characteristic of Bond
Metal and nonmetal Ionic Electrons transferred: to the nonmetal. The
metal atom becomes a cation (+) and the
nonmetal atom an anion (-)
Nonmetal and Covalent Electrons shared: neither atom transfers
nonmetal electrons to the other. Instead, the two atoms
share some electrons. The shared electrons
in a covalent chemical bond hold the bonding
, atoms together by attracting the positive
charges of their nuclei.
Metal and Metal Metallic Electrons pooled: (electron sea model)
pooled electrons are no longer localized on a
single atom, but delocalized over the entire
metal. The positively charged metal atoms are
then attracted to the sea of electrons, holding
the metal together.
Supramolecular interactions (between molecules)
- Dispersion = present between all
molecules and atoms; Dispersion
forces are the result of
fluctuations in the electron
distribution within molecules or
atoms. At any given instant, the
electrons in an atom or molecule
may be unevenly distributed. The
electrons may not be
symmetrically arranged around
the nucleus. This results in a
slightly positive side of the atom
(nucleus) and a slightly negative side of the atom (electrons). This fleeting charge
seperation is called an instataneous dipole or a temporary dipole. The temporary
dipole in one atom induces a temporary dipole in its neighbor. The resulting
attraction between the positive and negative charges creates the dispersion
force.
- Dipole-dipole = this force exist between all molecules that are polar. Polar
molecules have electron rich regions and electron deficient regions. The positive
end of one permanent dipole attracts the negative end of another. This attraction
is the dipole-dipole force. Polar molecules have higher melting and boiling points
than nonpolar molecules of similar molar mass.
- Hydrogen bonding: The large electronegativity differnce between hydrogen and
any of these electronegative elements ( F, O, N) causes the hydrogen atom to
have a fairly large partial positive charge within the bond, while the F, O, or N
atom has a fairly large partial negative charge. The interaction between the H
atom on one molecule and the F, O, or N on its neighbor is called a hydrogen
bond.
, - Ion-dipole: This force occurs when an ionic compound is mixed with a polar
compound. Ion-Dipole forces are the strongest of the types of intermolecular
forces discussed.
- Ion-ion
Density of Material classes : Metals > Ceramics > polymers
- Metals have close-packing (metallic bonding) and often have large atomic
masses
- Ceramics have less dense packing and often contain lighter elements
- Polymers have low packing density (often amorphous) and are lighter elements
(C,H, O)
- Composites have intermediate values
, Polymers = compounds which consist of very large molecules
formed by repeated joining of many small molecules
Polymerization is the process of joining together many small
molecules repeatedly to form very large molecules.
Monomers are compounds that join together repeatedly to
form polymer in polymerization.
Naturally occurring polymers (biopolymers): Proteins,
polysaccharides (cellulose, starch), nucleic acids (DNA,
RNA), rubber
Biopolymers are natural polymers produced by living organisms, consisting of
monomeric units that are covalently bonded to form larger molecules chains. They play
a wide range of structural, functional, and regulatory roles in nature, and their
biocompatibility and biodegradability make them valuable for biomedical,
environmental, and industrial applications.
Synthetic polymers are produced commercially on a very large scale. They have a wide
range of properties and uses. Plastics contain synthetic polymers. Examples of synthetic
polymers are: Polyethylene (PE), Polystyrene (PS), Polyvinyl chloride (PVC), Polyurethane
(PU), Nylon.
Semi-synthetic polymers = take something from nature and modify it (changing its
properties)! Therefore, it is synthetic!
Structural levels of polymers
1. Primary structure: refers to the order in which the repeating units appear in the
polymer and how they are connected (sequence of amino acids in proteins)
Co-polymers = polymers with 2 or more different units
Alternating: Monomers alternate in a
regular pattern, forming an A-B-A-B
sequence.
Block: Monomers form long blocks of each
type, creating segments like A-A-A-B-B-B
Random: Monomers are distributed
randomly, with no set order, as in A-B-B-A-
A-B.
Introduction to Biomaterials
Materials science = a study of solid functional materials
- Progress in materials science is often driven by the requirements for new
technology. On the other hand, advances in materials science often result in
associated advances in technology.
Biomaterials specifically refers to the development and application of materials in a
biomedical context.
Biomaterials are used to make artificial ECM!
3 main types of materials
1. Metals (metallic bond = keeps atoms together, conduct electricity ; electrons can
move)
2. Ceramics (brittle ; break very easily, ionic bond)
3. Polymers (long molecules, repeating units of monomers, functional groups ;
specific properties)
Chemical bonds
- Ionic bonds (NaCl): Ionic bonds are formed when two atoms exchange electrons
to create a positive and negative ion.
- Covalent bonds (H2O): Covalent bonds are formed when atoms share electrons
to create a molecule.
- Metallic bonds: Metallic bonds are created when metal atoms lose their
outermost electron to form positively charged ions.
Types of Atoms Type of Bond Characteristic of Bond
Metal and nonmetal Ionic Electrons transferred: to the nonmetal. The
metal atom becomes a cation (+) and the
nonmetal atom an anion (-)
Nonmetal and Covalent Electrons shared: neither atom transfers
nonmetal electrons to the other. Instead, the two atoms
share some electrons. The shared electrons
in a covalent chemical bond hold the bonding
, atoms together by attracting the positive
charges of their nuclei.
Metal and Metal Metallic Electrons pooled: (electron sea model)
pooled electrons are no longer localized on a
single atom, but delocalized over the entire
metal. The positively charged metal atoms are
then attracted to the sea of electrons, holding
the metal together.
Supramolecular interactions (between molecules)
- Dispersion = present between all
molecules and atoms; Dispersion
forces are the result of
fluctuations in the electron
distribution within molecules or
atoms. At any given instant, the
electrons in an atom or molecule
may be unevenly distributed. The
electrons may not be
symmetrically arranged around
the nucleus. This results in a
slightly positive side of the atom
(nucleus) and a slightly negative side of the atom (electrons). This fleeting charge
seperation is called an instataneous dipole or a temporary dipole. The temporary
dipole in one atom induces a temporary dipole in its neighbor. The resulting
attraction between the positive and negative charges creates the dispersion
force.
- Dipole-dipole = this force exist between all molecules that are polar. Polar
molecules have electron rich regions and electron deficient regions. The positive
end of one permanent dipole attracts the negative end of another. This attraction
is the dipole-dipole force. Polar molecules have higher melting and boiling points
than nonpolar molecules of similar molar mass.
- Hydrogen bonding: The large electronegativity differnce between hydrogen and
any of these electronegative elements ( F, O, N) causes the hydrogen atom to
have a fairly large partial positive charge within the bond, while the F, O, or N
atom has a fairly large partial negative charge. The interaction between the H
atom on one molecule and the F, O, or N on its neighbor is called a hydrogen
bond.
, - Ion-dipole: This force occurs when an ionic compound is mixed with a polar
compound. Ion-Dipole forces are the strongest of the types of intermolecular
forces discussed.
- Ion-ion
Density of Material classes : Metals > Ceramics > polymers
- Metals have close-packing (metallic bonding) and often have large atomic
masses
- Ceramics have less dense packing and often contain lighter elements
- Polymers have low packing density (often amorphous) and are lighter elements
(C,H, O)
- Composites have intermediate values
, Polymers = compounds which consist of very large molecules
formed by repeated joining of many small molecules
Polymerization is the process of joining together many small
molecules repeatedly to form very large molecules.
Monomers are compounds that join together repeatedly to
form polymer in polymerization.
Naturally occurring polymers (biopolymers): Proteins,
polysaccharides (cellulose, starch), nucleic acids (DNA,
RNA), rubber
Biopolymers are natural polymers produced by living organisms, consisting of
monomeric units that are covalently bonded to form larger molecules chains. They play
a wide range of structural, functional, and regulatory roles in nature, and their
biocompatibility and biodegradability make them valuable for biomedical,
environmental, and industrial applications.
Synthetic polymers are produced commercially on a very large scale. They have a wide
range of properties and uses. Plastics contain synthetic polymers. Examples of synthetic
polymers are: Polyethylene (PE), Polystyrene (PS), Polyvinyl chloride (PVC), Polyurethane
(PU), Nylon.
Semi-synthetic polymers = take something from nature and modify it (changing its
properties)! Therefore, it is synthetic!
Structural levels of polymers
1. Primary structure: refers to the order in which the repeating units appear in the
polymer and how they are connected (sequence of amino acids in proteins)
Co-polymers = polymers with 2 or more different units
Alternating: Monomers alternate in a
regular pattern, forming an A-B-A-B
sequence.
Block: Monomers form long blocks of each
type, creating segments like A-A-A-B-B-B
Random: Monomers are distributed
randomly, with no set order, as in A-B-B-A-
A-B.
