WS2 Nanosheets with Chemical Recognition Phase for the Detection of Salmonella
- Title
- WS2 Nanosheets with Chemical Recognition Phase for the Detection of Salmonella
- Author
- Juhee Han
- Advisor(s)
- 김종호
- Issue Date
- 2018-08
- Publisher
- 한양대학교
- Degree
- Master
- Abstract
- It is of great interest to modulate the dimension and functionality of
nanomaterials for designing biosensors capable of the selective and
sensitive detection of target molecules without the use of expensive and
fragile antibodies. Herein, I develop a new and simple approach for the
exfoliation and functionalization of transition metal dichalcogenide (TMD)
nanosheets for the selective and sensitive detection of Salmonella
typhimurium without the use of an antibody. To this end, WS2 nanosheets
are exfoliated by dextran (MW 40,000) in water via a sonication process.
As-prepared WS2 nanosheets have an average lateral size of 49 nm and
a thickness of 1.8 nm. In addition, the WS2 nanosheets exhibit intense
Raman scattering and photoluminescence (PL) that would be exploited as a
transduction signal for the optical detection of Salmonella typhimurium.
The WS2 nanosheets are then functionalized with a variety of tripeptides
bearing a nitrilotriacetate-copper complex (denoted as “WS2-Cu-TPs”)
through coordination of the sulfur atom with the copper moiety. The
resulting WS2-Cu-TPs maintain the intense Raman scattering of WS2 after
functionalization in an aqueous solution, but their PL is diminished. The
WS2-Cu-TP library then reacts with Salmonella typhimurium, E. coli
O157:H7, and Staphylococcus (S.) aureus to select the one showing the
selective recognition of Salmonella typhimurium. The intensive screening
process produces WS2-Cu-CHC being able to selectively recognize
Salmonella typhimurium against E. coli O157:H7, and S. aureus without
the use of any antibody. The affinity of WS2-Cu-CHC to Salmonella
typhimurium is found to be 76 nM, which is very comparable to that of a
Salmonella-specific antibody. The mechanistic study suggests that two
cysteine groups of the CHC tripeptide on the WS2 surface play an
important role in the selective recognition of Salmonella typhimurium.
Finally, the WS2-Cu-CHC sensor is able to detect a single copy of
Salmonella typhimurium in a rapid and simple manner.
- URI
- https://repository.hanyang.ac.kr/handle/20.500.11754/75860http://hanyang.dcollection.net/common/orgView/200000433550
- Appears in Collections:
- GRADUATE SCHOOL[S](대학원) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Theses(Master)
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