22
H. Kaur et al.
4.2 Characterizing Engineered Nanoparticles
and Biomolecule Interactions
Nanoparticles are referred to as the self-organized materials that form nanometersized particles ranging up to about 100 nm [48]. Accelerated growth in the development of the engineered nanomaterials has led to the amalgamation of this technology with different interdisciplinary scientific areas. It has expanded its enrollment in pharmaceutics, biomedical, biomaterial, electronics, and purification applications [49, 50]. This has led to an increase in the direct impact and association of
various nanomaterials with living species as well as the environment in which they
thrive [51]. They often interact with the cells and their constituents like amino acids,
proteins, DNA, lipid membrane, etc. The nano-bio interactions restructure and transform the fundamental properties of the nanomaterial surface like size, morphology,
surface functionality, and other mechanical properties, which affect their dynamics
and viability in vivo [52, 53]. Biomolecules also acquire distinct chemical structure and behavior upon interacting with the nanoparticles [51, 53]. The molecular
forces which operate during the nano-bio interactions majorly involve van der Waals
forces and electrostatic interactions, and certain short-range interactions including
steric forces or interactions with neighboring solvent molecules [52, 53]. Probing
such molecular interactions among the nanomaterials and biomolecules gives an
insight towards the structural stability and the dynamical activity of the biomolecule
associated nanoparticles in the aqueous solution [53].
Xu and Grassian [54] explored the interaction of TiO 2 nanoparticles with BSA
protein by varying the pH values of the solution (pH 7.4, 4.5 and 2.0) which modeled
the pH conditions of human blood, lung and stomach fluid environment, respectively.
In-situ adsorption and coverage profile of BSA over the TiO 2 nanoparticle surface
was studied using ATR-FTIR spectroscopy using AMTIR (Se/As/Ge glass) crystal.
Here the role of phosphate in BSA adsorption over TiO 2 nanoparticles is investigated
(shown in Fig. 11) in the amide region with time. BSA protein presents two characteristic vibrational peaks at ~1651 cm
−1 (amide I) and ~1548 cm
−1 (amide II). A
peak at ~1397 cm
−1 is attributed to the C–O carboxylate stretch mode of BSA. Thus,
the ratio of amide I/II peaks qualitatively determines the fate of BSA protein over the
TiO 2 surface. At pH 2.0, this peak ratio gets disturbed, which showcases that the BSA
proteins denature at acidic pH value when it gets adsorbed at the TiO 2 nanoparticle
surface. Conversely, BSA conformation at pH 7.4 and 4.5 stays consistent with time
(Fig. 11, panel a). In the presence of phosphate in solution, profile for both phosphate and BSA evolve in the spectra indicating their co-adsorption over TiO 2 . Even
at the acidic pH 2.0, co-adsorbing phosphate groups prevents the protein’s secondary
structure from denaturation after adsorption (Fig. 11, panel b). The finding of the
work epitomized the pH-dependent nanoparticle-protein interactions influenced by
the extraneous salts.
The intermolecular associations of the nanoparticle and single amino acid were
selectively studied in aqueous media by Tomar et al. [27] using ATR-FTIR spectroscopy, wherein the interaction of synthesized metal-oxide nanoparticles (i.e.,
H. Kaur et al.
4.2 Characterizing Engineered Nanoparticles
and Biomolecule Interactions
Nanoparticles are referred to as the self-organized materials that form nanometersized particles ranging up to about 100 nm [48]. Accelerated growth in the development of the engineered nanomaterials has led to the amalgamation of this technology with different interdisciplinary scientific areas. It has expanded its enrollment in pharmaceutics, biomedical, biomaterial, electronics, and purification applications [49, 50]. This has led to an increase in the direct impact and association of
various nanomaterials with living species as well as the environment in which they
thrive [51]. They often interact with the cells and their constituents like amino acids,
proteins, DNA, lipid membrane, etc. The nano-bio interactions restructure and transform the fundamental properties of the nanomaterial surface like size, morphology,
surface functionality, and other mechanical properties, which affect their dynamics
and viability in vivo [52, 53]. Biomolecules also acquire distinct chemical structure and behavior upon interacting with the nanoparticles [51, 53]. The molecular
forces which operate during the nano-bio interactions majorly involve van der Waals
forces and electrostatic interactions, and certain short-range interactions including
steric forces or interactions with neighboring solvent molecules [52, 53]. Probing
such molecular interactions among the nanomaterials and biomolecules gives an
insight towards the structural stability and the dynamical activity of the biomolecule
associated nanoparticles in the aqueous solution [53].
Xu and Grassian [54] explored the interaction of TiO 2 nanoparticles with BSA
protein by varying the pH values of the solution (pH 7.4, 4.5 and 2.0) which modeled
the pH conditions of human blood, lung and stomach fluid environment, respectively.
In-situ adsorption and coverage profile of BSA over the TiO 2 nanoparticle surface
was studied using ATR-FTIR spectroscopy using AMTIR (Se/As/Ge glass) crystal.
Here the role of phosphate in BSA adsorption over TiO 2 nanoparticles is investigated
(shown in Fig. 11) in the amide region with time. BSA protein presents two characteristic vibrational peaks at ~1651 cm
−1 (amide I) and ~1548 cm
−1 (amide II). A
peak at ~1397 cm
−1 is attributed to the C–O carboxylate stretch mode of BSA. Thus,
the ratio of amide I/II peaks qualitatively determines the fate of BSA protein over the
TiO 2 surface. At pH 2.0, this peak ratio gets disturbed, which showcases that the BSA
proteins denature at acidic pH value when it gets adsorbed at the TiO 2 nanoparticle
surface. Conversely, BSA conformation at pH 7.4 and 4.5 stays consistent with time
(Fig. 11, panel a). In the presence of phosphate in solution, profile for both phosphate and BSA evolve in the spectra indicating their co-adsorption over TiO 2 . Even
at the acidic pH 2.0, co-adsorbing phosphate groups prevents the protein’s secondary
structure from denaturation after adsorption (Fig. 11, panel b). The finding of the
work epitomized the pH-dependent nanoparticle-protein interactions influenced by
the extraneous salts.
The intermolecular associations of the nanoparticle and single amino acid were
selectively studied in aqueous media by Tomar et al. [27] using ATR-FTIR spectroscopy, wherein the interaction of synthesized metal-oxide nanoparticles (i.e.,