135Materials for Nanosensors
with molecules and clusters. Interestingly, the notable feature about this
class of materials is about the “nothingness” within them, that is, the pore
space.
What are nanoporous materials? Nanoporous materials are those having
pore sizes less than 100 nm. Such materials are found in abundance in the
natural world, both in biological systems and natural minerals. The walls of
animal cells are made of nanoporous membranes. Petroleum industry has
been long using nanoporous materials called zeolites (microporous, alumi-
nosilicate minerals) as catalysts (Sun et al. 2008). Aerogels (derived from a
gel in which the liquid component of the gel has been replaced with a gas,
aerogels are manufactured materia ...