1. UNIVERSIDAD DE LAS FUERZAS ARMADAS -ESPE
DEPARTAMENTO DE CIENCIAS DE LA VIDA Y LA AGRICULTURA
NAME: Israel Cajas
NRC: 2786
Date: 01/05/2017
Subject: Biophysics
Chemistry controlled on tiniest scale can create hollow nanoparticles
Researchers watched at near-atomic resolution as iron nanoparticles transformed into iron
oxide.This is the first time the oxidation process has been observed in such detail. When a
metal oxidizes, its atoms mix and mingle with oxygen atoms to create a new material.
Chemist Yugang Sun and his colleagues at Temple University in Philadelphia are trying to
create hollow iron oxide nanoparticles that could serve as catalysts to speed up chemical
reactions or as vessels to deliver drugs or store energy in chemical form. But making these
nanoshells from iron nanoparticles requires precise control over the oxidation process. If
oxygen atoms work their way into an iron nanoparticle faster than the iron atoms can
diffuse out, that nanoparticle becomes a tight, solid ball, Sun says. If the iron diffuses out
faster than the oxygen comes in, on the other hand, it becomes the hollow sphere that Sun’s
lab wants.
Controlling that process is difficult because scientists haven’t been able to watch it happen,
because high-powered microscopy techniques can disrupt the reaction or show the action
in only two dimensions. Sun’s team tried a different approach to observe the reaction, by
shooting X-rays at many identical iron nanoparticles suspended in a liquid. By tracking how
the X-rays bounced off many small, uniform iron nanoparticles, the researchers were able
to reconstruct where individual atoms were going as the particles oxidized into hollow shells
over the course of several hours. The researchers watched as the iron moved out of the
center of the nanoparticle to react with the oxygen, initiallyforming many smallholes inside
the nanoparticle. Eventually, those empty spaces merged together to form one big void in
the middle of the nanoparticle (Science, 2017).
Summary of Paper
Bibliography:
Olsen,S.,& Krause,K.(2017). Activityof xyloglucanendotransglucosylases/hydrolasessuggestsa
role duringhostinvasionbythe parasiticplantCuscutareflexa. PloSOne,12(4),e0176754.
https://doi.org/10.1371/journal.pone.0176754
2. Science,N.(2017). Rulesrestrictingartificial transfatsare goodfor hearthealth| Science News.
Recuperado22 de abril de 2017, a partir de https://www.sciencenews.org/article/rules-
restricting-artificial-trans-fats-are-good-heart-health
