posted on 2021-03-18, 14:34authored byZahra
Hosseinpour Feizi, Pedram Fatehi
Although
antibiotics are beneficial for treating infections, their
release into the environment has raised global concerns. In this work,
the interactions of cellulose nanocrystal (CNC) derivatives with sulfamethoxazole
(SMX), ciprofloxacin (CIP), and doxycycline (DOX) antibiotics were
studied fundamentally. CNC was carboxyalkylated to bear different
carbon chain lengths but similar negative charges on its surface.
The highest level of adsorption of DOX on the carboxypantadecanated
CNC (i.e., carboxyalkylated CNC with more carbon spacer, PCNC) occurred
at pH 6.0, which was due to the electrostatic and π interactions
along with hydrogen bonding. The contact angle and quartz crystal
microbalance (QCM) adsorption analyses revealed a faster interaction
and adsorption of DOX than other antibiotics on PCNC. The results
also depicted the diffusion of DOX into the porous structure of CNC
derivatives, especially that of PCNC. Also, a more compact adsorbed
layer of DOX was formed on PCNC than on other CNC derivatives. Carboxyalkylation
was observed to slightly reduce the surface area of CNC, while the
antibiotic adsorption drastically increased the surface area of CNC
due to their adsorption on the surface. XPS analysis revealed that
carboxyalkylation significantly enhanced the C–C/C–H
bond, while antibiotic adsorption on PCNC enhanced C–N/C–O
and C–C/C–H bonds in antibiotic-loaded CNC samples.
Overall, carboxyalkylated CNC was observed to have an outstanding
affinity for capturing antibiotics, especially DOX, which could pave
the way for the use of CNC in such applications that surface/antibiotic
interactions were essential.