Biofilm Inhibition by Nanoparticles - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 378

2.2 Liquid Phase Nanoparticle Fabrication
Liquid phase fabrication involves wet chemistry and the general process includes
the surface reaction of solid and liquid precursors to produce corresponding inter-
mediate products. Such intermediate products are converted to primary particles
either by nucleation or condensation similar to gas phase fabrication, followed by
growth or agglomeration to produce nanoparticles or nanoclusters, respectively.
Methods that employ liquid phase fabrication are:
1. Co-precipitation (Murray et al. 2000 )
2. Solvothermal methods (Yang et al. 2006 )
3. Sol-gel methods (Yu et al. 2004 )
4. Synthesis in structure media (e.g., Microemulsion) (Capek 2004 )
5. Microwave synthesis (Tsuji et al. 2005 )
6. Sonochemical synthesis (Zhang and Yu 2003 )
2.3 Biological Synthesis of Nanoparticles
Synthesis of nanoparticles catalyzed by bacteria or fungi or their products is of
considerable interest as it employs cleaner and greener technology. Numerous fungi
and bacteria have been utilized for the bioconversion of raw chemicals into
nanoparticles. For instance, the ability of the marine yeast Yarrowia lipolytica to
catalyze the synthesis of gold nanoparticles has been reported (Agnihotri
et al. 2009 ; Apte et al. 2013a , b ). Biosynthesis of silver, gold, and bimetallic
nanoparticles by fungi like Phanerochaete chrysosporium , Penicillium sp., and
Neurospora crassa has also been reported (Castro-Longoria et al. 2011 ;Du
et al. 2010 ; Vigneshwaran et al. 2006 ). Similarly, the synthesis of silver
nanoparticles with antimicrobial potential by psychrophilic bacteria such as Pseu-
domonas antarctica and Arthrobacter kerguelensis has also been reported (Shivaji
et al. 2011 ) . Lactobacillus fermentum (Sintubin et al. 2009 ) and Shewanella
oneidensis (Suresh et al. 2010 ) were also shown to catalyze the production of silver
nanoparticles with antimicrobial potential.
Though there are numerous reports on the microbe-mediated synthesis of
nanoparticles, very few studies have described the biomolecules involved in this
synthesis. For example, nitrate reductase along with a protein from Aspergillus
niger and nitrate reductase along with rhamnolipids from P. aeruginosa were
shown to be indispensable for the synthesis of nanoparticles (Gade et al. 2008 ;
Kumar and Mamidyala 2011 ). Similarly, the role of cell-bound melanin produced
by the yeast Y. lipolytica and certain proteins produced by marine fungi
A. tubingensis and Bionectria ochroleuca in the synthesis of silver nanoparticles
with antibiofilm activity have been reported recently (Apte et al. 2013a , b ; Rodri-
gues et al. 2013 ).