Size and Shape Selective Metal Oxide Nanomaterials …
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may dissociate or the ions may adsorb on to the NMs surface from solution (stern
layer). Such adsorption promotes formation of a layer made of counter ions which
is called diffuse layer. The potential that exists between the layer boundary is called
as zeta potential [50]. Analysis of zeta potential is very much useful for number
of applications such as electro-kinetic transport of particles, biocompatibility study,
characterization of polymers used in biomedical fields. Mikolajczyk et al. [51] have
studied the zeta potential of several MONMs in different experimental conditions and
have proposed quantitative structure-property relationship for predicting agglomeration or aggregation phenomena. The zeta potential is the result of surface ionization, lattice ion dissolution, and ion adsorption. It was mentioned that the NMs size
affects the zeta potential values which are size and concentration-dependent as per
the simplified molecular line-entry systems model [52].
6.5 Biocompatibility Study
The biocompatibility of NMs should be considered an important criterion to use it
in biological systems. Many MONMS are known for its photocatalytic performance
thus it can be considered for anti-bacterial applications. Also, when MONMs are
used with organic chemicals it can impart additional activity such as hydrophobicity
(which is a measure of bio-adhesion). The biocompatibility studies can be performed
using an enzyme metabolic assay [53] in the required cell cultures. Thus the MONMs
should exhibit suitable non-toxic effect to the test physiological condition and at the
same time it should render anti-bacterial properties. The MONMs can be modified
or surface-functionalized with other biologically active materials in order to protect
against unwanted aggregation, non-specific interaction, and toxicity.
7 MONMs-from Synthesis to Product Formation
The sequence of steps involved in commercial product formation are given below as
per the review article by Stavis et al. [54].
a. Synthesizing materials aiming at specific or useful properties: Control over
synthesis, physicochemical parameters, identification of the process variations
to reduce the heterogeneity and removal of chemical contaminants should be
considered while synthesizing the MONMs.
b. Stabilization: This allows internal storage (against Ostwald ripening and other
aggregative ingredients) and for transfer between other liquids (in ionic liquids
and further centrifugation before dispersing in the application medium). Storage
of MONMs against thermal influence involves lyophilization or external coatings
(such as polymers) which can increase its stability. Stabilization to sustain the
electrosteric repulsion can be maintained by utilization of polyethyleneglycol.
95
may dissociate or the ions may adsorb on to the NMs surface from solution (stern
layer). Such adsorption promotes formation of a layer made of counter ions which
is called diffuse layer. The potential that exists between the layer boundary is called
as zeta potential [50]. Analysis of zeta potential is very much useful for number
of applications such as electro-kinetic transport of particles, biocompatibility study,
characterization of polymers used in biomedical fields. Mikolajczyk et al. [51] have
studied the zeta potential of several MONMs in different experimental conditions and
have proposed quantitative structure-property relationship for predicting agglomeration or aggregation phenomena. The zeta potential is the result of surface ionization, lattice ion dissolution, and ion adsorption. It was mentioned that the NMs size
affects the zeta potential values which are size and concentration-dependent as per
the simplified molecular line-entry systems model [52].
6.5 Biocompatibility Study
The biocompatibility of NMs should be considered an important criterion to use it
in biological systems. Many MONMS are known for its photocatalytic performance
thus it can be considered for anti-bacterial applications. Also, when MONMs are
used with organic chemicals it can impart additional activity such as hydrophobicity
(which is a measure of bio-adhesion). The biocompatibility studies can be performed
using an enzyme metabolic assay [53] in the required cell cultures. Thus the MONMs
should exhibit suitable non-toxic effect to the test physiological condition and at the
same time it should render anti-bacterial properties. The MONMs can be modified
or surface-functionalized with other biologically active materials in order to protect
against unwanted aggregation, non-specific interaction, and toxicity.
7 MONMs-from Synthesis to Product Formation
The sequence of steps involved in commercial product formation are given below as
per the review article by Stavis et al. [54].
a. Synthesizing materials aiming at specific or useful properties: Control over
synthesis, physicochemical parameters, identification of the process variations
to reduce the heterogeneity and removal of chemical contaminants should be
considered while synthesizing the MONMs.
b. Stabilization: This allows internal storage (against Ostwald ripening and other
aggregative ingredients) and for transfer between other liquids (in ionic liquids
and further centrifugation before dispersing in the application medium). Storage
of MONMs against thermal influence involves lyophilization or external coatings
(such as polymers) which can increase its stability. Stabilization to sustain the
electrosteric repulsion can be maintained by utilization of polyethyleneglycol.