354

22 Biofunctionalized Nanomaterials for Sensing and Bioremediation of Pollutants

nanoparticle is used for the reduction of dyestuff and hydrocarbons from polluted

water. These nanoparticles are synthesized by reverse-phase surface adsorption,

and they retain their activity even after repeated use [35]. Ginet et al. [36] have

successfully developed an easy to sieve, stable, and reusable biocatalyst to degrade

ethyl-paraoxon pesticide using engineered lipid-coated nanomagnetic particle

conjugated with phosphohydrolases. In vivo immobilization of phosphotriesterase

derived from bacteria was studied for its role in soil and water remediation.

Magnetic nanoparticle-conjugated metalloenzyme can be produced in a single step

and was able to hydrolyze harmful pesticides like paraoxon. Paraoxon pesticides

are lethal to human due to its neurotoxic nature [37]. Peroxidase enzymes have an

essential role in removing phenolic compounds like azo dyes, a prominent pollutant

found in textile industry waste. Fe3O4-conjugated peroxidase enzyme altered with

the help of glutaraldehyde co-precipitation was able to reduce the azo dyes present

in wastewater to a considerable amount [38].

22.5

Biofunctionalized Nanoparticle-Based Sensors

for Environmental Application

Biofunctionalized nanoparticle-based sensors have a biomolecule-conjugated

nanoparticle which interacts with the analyte, and a signal transducer generates

the signal (Figure 22.1). The generated signal may be directly visible or processed

and quantified by other electronic components. Nanoparticle-based biosensors

generally provide a quick result when compared to conventional technologies like

gas/liquid chromatography. However, various kinds of biomaterials are used in

combination with nanoparticles for the development of sensors, but the majority

of them have enzymes or antibodies as a primary bioelement. Sensors based on the

quantification of electrochemical properties are generally based on the redox reac-

tion. In general, biosensors can be of two types, i.e. colorimetric or electrochemical.

Recognition

element

Analyte

Biomolecules and

nanoparticles

Signal Transducer

Visible Result

Quantifiable result measured

by electrical component

Figure 22.1

Components of biofunctionalized nanosensor.