Multivalent aptamer refers to a technique that joins two or more identical or different types of aptamer
monomers together, with or without the presence of structural or other functional elements. As a rapid
and easy method for fabricating the multivalent aptamer constructs, rolling circle amplification (RCA)
has attracted great attention in recent decades. The incorporation of properly designed structural
elements, such as intra-molecular spacers, have been shown to greatly enhance the efficiency of the
multivalent aptamer system [1]. The objective of this current study is to systemically investigate the
effect of different lengths of poly thymine spacer designs (polyT, from no spacer/NT, 5T, 10T, and 15T)
on the capturing performance of RCA-generated multivalent system. To achieve this, we designed four
circular probe templates by inserting zero, five, ten, and fifteen adenine bases (polyA). These polyA
domains in the circular probe template are complementary to polyT with respective lengths in between
the adjacent aptamers on the resultant RCA products (RCAPs). We found that the resultant RCAPs with
length shorter than 10T showed a lack or low ability to capture target cells E.Coli O157:H7. When
spacer lengths reach or exceed 10T, the capturing performance of the respective multivalent aptamer
chain is significantly enhanced. This phenomenon can be explained by larger hydrodynamic sizes and
less nonspecific secondary structures observed in RCAP with spacer length no less than 10T. Moreover,
we found that there is also a trade-off that the number of polyA bases added into the circular probe
template can significantly impair the efficiency of RCA reaction in respective to cyclization yield and
amplification rate. The results of this research explain with details how the design of spacer affects RCA
reaction efficiency and RCAPs’ capturing performance, which provides ideas in designing an efficient
RCA-generated multivalent system.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/43720 |
| Date | 21 June 2022 |
| Creators | Wang, Zhong |
| Contributors | Cao, Xudong |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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