We pre
sent here a
synthetic method for fabricating hollow magnetic me
soporou
s nanocompo
site
s (diameter~ 400 nm) made up of ferrite nanoparticle
s incorporated to the me
soporou
s shell (
shell thickne
ss ~ 50 nm)of carbon cap
sule
s. Thi
s methodology ha
s been applied to the in
sertion of different ferrite
s such a
s iron oxide
spinel (Fe
3O
4/
![](/image<font color=)
s/gifchar
s/gamma.gif" BORDER=0 >-Fe
2O
3), CoFe
2O
4, NiFe
2O
4, and MnFe
2O
4. The
size of the
se inorganic nanoparticle
s (~9-17nm) can be modulated ea
sily by varying the temperature of
synthe
si
s, a
s demon
strated in the ca
se of the ironoxide
spinel pha
se. An important characteri
stic of the
se nanocompo
site
s i
s that, in
spite of the large amount
sof inorganic nanoparticle
s depo
sited (30 or 50 wt %), they retain a large poro
sity made up of me
sopore
s(~2-4 nm). Moreover, the inner core of the
se nanocompo
site
s remain
s completely empty becau
se the ferritenanoparticle
s are depo
sited exclu
sively on the porou
s carbon layer. We have demon
strated the u
sefulne
ss ofthi
s kind of nanocompo
site
s for the immobilization of an enzyme (ly
sozyme). The re
sult
s obtained
sugge
stthat the enzyme i
s stored mainly in the hollow core of the magnetic cap
sule
s. Moreover, we have proved thatthe nanocompo
site loaded with the enzyme can be manipulated ea
sily by mean
s of an external magneticfield.