Post on 15-Jul-2020
Kyoungja Woo
Synthesis & Antimicrobial Efficacy of Magnetic Silica Microspheres Decorated with AgNPs
10th U.S.-Korea Nano Forum, Boston, MA, Oct 15-16, 2013
Needs for Virus Removal System
(Air, Water)
OUTBREAKS OF VIRAL INFECTION !
SOCIAL DEMAND
Nano Convergent Materials Tech.
Motivation of the Project
AgNP interaction with bacterial cells
1) Release Ag+ and generate ROS 2) Interact with membrane protein 3) Accumulate in the cell membrane 4) Enter into the cell
J. Nanopart. Res. (2010) 12:1531
AgNPs
The smaller, the better
AgNP interaction with microbial membranes
The AgNPs bind to the gp120 knobs (cysteine location) of HIV virus
Journal of Nanobiotechnology 2005, 3:6
AgNP(<10 nm) & HIV-I
Degradation of the membrane Structure
Journal of Colloid and Interface Science 2004, 275, 177
AgNP(~12 nm) & E. Coli
b
d
Major challenges in practical utilization of AgNPs 1. Aggregation of AgNPs
2. Environmental release of AgNPs
* The smaller, the better?
Organic Polymer-AgNP Composite
Polysulfone ultrafiltration membrane impregnated with AgNP (Membrane fabrication: 15% PSf, 10% PVP, 75% NMP, 0.9% AgNP)
without AgNP
with AgNP
After filtration of 0.4 L/cm2, 10% AgNP loss !
Water Research 2009, 43, 715
▪ Magnetic hybrid colloid decorated with AgNP (AgNP@MHC)
Inorganic Superparamagnetic AgNP Composite
Inorganic Superparamagnetic AgNP@MHC
S. Coverage: 8.8% 25% 18%
Inorganic Superparamagnetic Ag/Au@MHC
XPS analysis of Ag/Ag@MHC
Fe 3 O 4
Silica
AP
+
+ +
+
+
+
+ +
+ +
+
nAg30@MHC
Ag 3d5/2, 3d3/2 N 1s
AP@MHC + Ag+
AP@MHC
▪ Repeatedly usable noble metal nanocatalyst composite
Catalytic Property of Ag/Au@MHC
ka = 0.095/min TOF(nAg/Au@MHC) = 3.8×10-3/s TOF(chitosan-AgNP5nm) = 0.97×10-3/s
Sci. Rep. 2013, 3, 1497, Woo
Ag/Au@MHC
Antimicrobial effects of AgNP@MHC
E. Coli CN13 Bacteriophage MS2
E.coli CN13+Ag30@MHC as-prepared
E.coli CN13 E.coli CN13+Ag30@MHC @30 min
E.coli CN13+Ag30@MHC @60 min
AgNP@MHC bites away bacteria
AgNP@MHC chemisorbs viruses (Bacteriophage MS2)
Tyr230
Asn228
His181
Arg226
Glu213 Asp94
Arg226
Glu213
His181
Asn228
Asp94 Tyr230
Influenza viral HA structure (interactions at the dimer interface)
from Prof. Kyunghyun Kim in Korea University
Mechanistic study for antimicrobial effects of AgNP (30 nm)
(A) (B) (C)
1 h 1 d
Scale-up synthesis for practical application
TEOS
Acknowledgment Fund: Ministry of Science, ICT & Future Planning through NRF of Korea (GNT program), KIST People: Dr. Hye Hun Park (KIST), Ms. Mihwa Seo (KIST), Dr. Jae-Pyoung Ahn (KIST), Mr. SungJun Park (SNU), Prof. GwangPyo Ko (SNU) Mr. Yoonhaeng Cho (Yonsei U.) Prof. Jeongho Hwang (Yonsei U.)
Thank you !