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Bioremediation for Sustainable Environmental Cleanup

like microparticles, fibres, sheets and scaffolds can be synthesized. Biomolecules present in

biohybrid materials could perform required functions and enhance the applicability of biohybrids

for drug delivery, biomedical engineering, biosensing, wearable devices, etc. (Mishra et al. 2017,

Mishra et al. 2021a, Rivera-Tarazona et al. 2021, Wang et al. 2022). Several reviews are available

on biohybrid materials (Nguyen et al. 2018, Mishra et al. 2020b, Wang et al. 2022).

15.3 Biocomponent and its Importance in Biohybrid Material

Living cells are valuable assets. A microorganism acts as a large amount full of enzymes thus

the microorganism present in the biohybrid can be used for various bioprocesses as well as for

environmental monitoring. Although, living cells are very useful, however they are sensitive,

vulnerable to the external environment and can be applied in relatively mild conditions. Thus, to

improve its applicability it is proposed to develop a protective covering using well suited materials.

Support with tuneable physicochemical properties could also be best suited as a protective covering

which could improve bio-interface characteristics and cellular functions. Sphingomonas sp. bacterium

has an organophosphorus hydrolase (OPH) enzyme which hydrolyzes methyl parathion pesticide

into a coloured product. However, poor storage stability of periplasmic enzyme was a matter of

concern so, Sphingomonas sp. cells have been associated with functionalized silica nanoparticles to

develop a biohybrid and a developed biohybrid was immobilized on 96 well microplates (Mishra

et al. 2017). A developed system was explored as biosensor for detecting methyl parathion pesticide.

This study showed that the association of microorganisms with inorganic materials is beneficial for

both the components. In a biohybrid material the limitation associated with one component can be

overcome by the presence of another component. Thus, a biohybrid material offers superior features

of both the components, wherein both components have their own importance.

Many living cells and microorganisms have been applied as biocomponents to develop biohybrid

materials. In one study, S. lactis cells were combined with silica nanoparticles using an evaporation

induced self-assembly process, and a biohybrid of silica NP-S. lactis cells were synthesized which

was applied for removing uranium (Mishra et al. 2014). On a similar line of studies, S. cerevisiae

cells were connected with silica nanoparticles and a prepared biohybrid was used for the removal of

mercury (Shukla et al. 2020).

Microorganisms show distinctive features in the presence of various stimuli like temperature,

light and presence of oxygen (Rivera-Tarazona et al. 2021) therefore, these features can be

exploited to develop biohybrid-based robotics (Nguyen et al. 2018). Biohybrid-based robotics can

be efficiently used for the detection of various pollutants and to overcome the limitations associated

with conventional robotics. Microorganisms like Escherichia coli, could also be genetically modified

to perform specific functions (Gerber et al. 2012). Even, living cells (natural killer (NK) cells, stem

cells, islet cells and probiotics) which have therapeutic properties can be combined with suitable

support as this will help to improve viability and cellular activities (Wang et al. 2022).

15.4 Support Material and its Importance in Biohybrid

A support is usually a solid insoluble matrix and a wide variety of matrices have been applied as a

support. As reported earlier, a support should have following characteristics (Figure 15.2) (Mishra

2019):

i. It should offer a higher surface area and various functional groups.

ii. It should demonstrate high mechanical and chemical stability.

iii. It should be biocompatible, environmentally and user friendly.

iv. It should show high affinity and provide a favourable microenvironment to target a molecule.

v. It should be easily and widely available. It can also be obtained from a reliable commercial

source.