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22 Biofunctionalized Nanomaterials for Sensing and Bioremediation of Pollutants

22.3.4

Adsorption

In this technique of biofunctionalization, nanoparticles hold biomaterial(s) as a thin

film on the outer surface. Adsorption of any molecule onto the outer surface of

a nanoparticle is also known as “corona” formation. Adsorption mostly relies on

the surface charge of both nanomaterial and biomaterial, and these parameters are

sensitive to pH. Generally used biomaterials for adsorption-based functionalization

include lipids, carbohydrates, DNA, proteins, dendrimers, small micelles, liposomes,

and biologically or synthetically manufactured polymer. However, the exact mecha-

nism of surface protein adsorption remains elusive. Surface modification enhances

the adsorption of biomolecules to nanoparticles.

22.4

Commonly Functionalized Biomaterials and Their

Role in Remediation

The role of biofunctionalized nanomaterials for environmental applications has

been a critical focus of progressive research with a particular emphasis on reducing

pollution and the elimination of diverse pollutants and xenobiotics from solid waste,

water, and air. Integration of biomaterials of immense potential and nanoparticles

of remarkable properties makes biofunctionalized nanoparticles a promising tool

to be used in the environmental application. Commonly employed biomaterials

for nanoparticle conjugation and pollution remediation include biopolymers,

biosurfactants, nucleic acid, enzymes, proteins, and polypeptides (Table 22.1).

22.4.1

Biopolymers

Polymeric molecules having a bio-origin containing small monomeric units which

are held together by the covalent bond are called biopolymers. Polymers derived

using synthetic chemistry using resins, proteins, amino acid, fats, sugars, and oil of

biological origin are also called biopolymers. The primary factor which promotes the

use of biopolymer over fossil-based or synthetic polymer is their inherent property

of biodegradability. Biopolymer doesn’t cause harmful byproduct upon degradation,

which makes them a sustainable component for bioremediation. “Polyol method” is

often used for the synthesis of polymer nanomaterial in which the metal component

is reduced and dissolved at high temperature by different alcohol-based solvents. The

use of alcohol as a reducing agent is not problematic as the produced byproducts are

generally less harmful organic materials. Lipophilic and oleophilic active particles

created by lipophilic plasma polymerization are widely used for water refinement.

Nanoparticles-conjugated biopolymers are also used for the degradation of a wide

variety of pollutants, including dyes and heavy metals, and can be used for soil and

water remediation.

Rosin amidoxime-conjugated magnetic nanoparticles are used for the removal

of crude oil-based PAH from water bodies. The synthesis mechanism for the