98
A. Antony and J.-H. Boo
10 The MONMs-Biomolecular Interactions
When the nanoparticles are suspended in a medium containing biological culture, it
encounters with different biological interfaces such as lipids, DNA, proteins, polysaccharides, flavonoids, etc. Understanding such interactions at the nano-bio interfaces
would help in preferring a suitable approach for safe utilization of NMs in pharmaceutical, biomedical and clinical industries. Inside biological culture medium, interactions exist between functional groups of MONMs and biomolecules such as phospholipid, lipopolysaccharide, protein, and lipoteichoic acid present over the bacterial envelop which contribute for interaction at the interface. The functional groups
present in biomolecules enhance adhesion to different surfaces. Similarly, different
kinds of non-specific interactions such as dipole-dipole, electrostatic, hydrophobic,
hydrogen-bond, and van der Waals interactions play important roles in adhesion of
bacteria on any MONMs [64].
The NMs (such as polymers, biomarkers, metals and drugs) that interact with
biological systems can be understood (in three ways) from the research done by
different research groups around the world and compiled in a review article by Zhang
et al. [65]. Those are (a) protein binding (b) ligand-mediated interactions and (c)
interaction due to intracellular processing. Such understanding may further extend
to oxide nanomaterials logically it seems.
The biological makeup such as blood, plasmic fluid and secretions (made of
proteins and other biochemicals) that interact with protein-coated NMs are mainly
size-dependent. The hydrodynamic size may increase due to functionalization and
lead to aggregation. Thus the final size of NMs becomes an important criterion
to expect specific-binding. The bimolecular proteins (such as albumin, fibrinogen,
and apoliproteins) are reported to bind easily with MONMs (such as iron oxide)
and carbon nanotubes [65]. The plasma protein corona recognizes NMs or foreign
bodies firstly and responds immunologically which depends on the surface properties and size. The high or low-affinity binding of proteins is determined by their
hydrophobicity character. In addition, if the protein’s isoelectric point (pI) is greater
than 5.5 then it can easily bind with NMs [66]. Ligand-mediated interactions are
particularly useful for spatial localization, placing of NMs exactly at the diseased
tissues, and to remove adverse effects caused by off-target moieties. For this mode,
the MONMs are modified using a surface ligand to facilitate preferential interaction
to a diseased tissue or binding with it. The ligands are usually small molecules, antibodies, proteins, and aptamers. Intra-cellular processes are related to the safe delivery
of drugs loaded NMs with ease intra-cellular trafficking. Appropriate engineering
and design of carriers would deliver therapeutics to the specified organelles. For
inside cell delivery, polymer-MONMs conjugate using covalent bonding of chemo
drugs with hydrophilic polymers [65] can be utilized.
A. Antony and J.-H. Boo
10 The MONMs-Biomolecular Interactions
When the nanoparticles are suspended in a medium containing biological culture, it
encounters with different biological interfaces such as lipids, DNA, proteins, polysaccharides, flavonoids, etc. Understanding such interactions at the nano-bio interfaces
would help in preferring a suitable approach for safe utilization of NMs in pharmaceutical, biomedical and clinical industries. Inside biological culture medium, interactions exist between functional groups of MONMs and biomolecules such as phospholipid, lipopolysaccharide, protein, and lipoteichoic acid present over the bacterial envelop which contribute for interaction at the interface. The functional groups
present in biomolecules enhance adhesion to different surfaces. Similarly, different
kinds of non-specific interactions such as dipole-dipole, electrostatic, hydrophobic,
hydrogen-bond, and van der Waals interactions play important roles in adhesion of
bacteria on any MONMs [64].
The NMs (such as polymers, biomarkers, metals and drugs) that interact with
biological systems can be understood (in three ways) from the research done by
different research groups around the world and compiled in a review article by Zhang
et al. [65]. Those are (a) protein binding (b) ligand-mediated interactions and (c)
interaction due to intracellular processing. Such understanding may further extend
to oxide nanomaterials logically it seems.
The biological makeup such as blood, plasmic fluid and secretions (made of
proteins and other biochemicals) that interact with protein-coated NMs are mainly
size-dependent. The hydrodynamic size may increase due to functionalization and
lead to aggregation. Thus the final size of NMs becomes an important criterion
to expect specific-binding. The bimolecular proteins (such as albumin, fibrinogen,
and apoliproteins) are reported to bind easily with MONMs (such as iron oxide)
and carbon nanotubes [65]. The plasma protein corona recognizes NMs or foreign
bodies firstly and responds immunologically which depends on the surface properties and size. The high or low-affinity binding of proteins is determined by their
hydrophobicity character. In addition, if the protein’s isoelectric point (pI) is greater
than 5.5 then it can easily bind with NMs [66]. Ligand-mediated interactions are
particularly useful for spatial localization, placing of NMs exactly at the diseased
tissues, and to remove adverse effects caused by off-target moieties. For this mode,
the MONMs are modified using a surface ligand to facilitate preferential interaction
to a diseased tissue or binding with it. The ligands are usually small molecules, antibodies, proteins, and aptamers. Intra-cellular processes are related to the safe delivery
of drugs loaded NMs with ease intra-cellular trafficking. Appropriate engineering
and design of carriers would deliver therapeutics to the specified organelles. For
inside cell delivery, polymer-MONMs conjugate using covalent bonding of chemo
drugs with hydrophilic polymers [65] can be utilized.