the ppt is about crisper and its usage in metal detection

1. Applying CRISPR/Cas system as
a signal enhancer for DNAzyme-
based lead ion detection
Presented by:
M Imran Javed
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2. Introduction
• Heavy metals can pollute the air, water and soil.
• These metals pollute water and soil, pollute crops
and humans through food chain.
• Adverse effects on human health.
• Common heavy metals that harm human heath are:
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3. Methods for heavy metal
detection
• Atomic absorption spectrometry
• Atomic emission spectrometry
• Fluorescence spectro-photometry
• Electrochemistry
• Equipped labs and professionals are required.
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4. DNAzyme
• It is a metal dependent enzyme.
• It selectively recognizes metal ions.
• DNAzyme is composed of:
o Enzyme chain(E chain)
o Substrate chain( S chain)
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5. Mechanism of DNAzyme
(Witka et al., 2009)
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6. (Liu et al., 2013) 6

7. Clustered regularly interspaced short
palindromic repeats (CRISPR)
• Used as gene editing tool
• Used for nucleic acid detection
• Cas12, Cas13 and Cas14 combined with PCR or
recombinase polymerase amplification (RPA) are used
for nucleic acid detection.
• Cas12 has collateral cleavage activity.
• It recognizes the ssDNA and dsDNA and cleaves it.
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8. Cas12 collateral cleavage activity
(Zhang et al., 2019)
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9. DNAzyme-CRISPR method
• A combination of DNAzyme and CRISPR is used to
detect lead ion.
• DNAzyme recognizes lead ion and produces ssDNA.
• This ssDNA activates the collateral cleavage activity of
CRISPR.
• DNAzyme-CRISPR method combines the high
specificity of DNAzyme and the high sensitivity of
CRISPR.
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10. Problem statement
On-site detection of heavy metals with high
sensitivity and specificity is a major concern
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11. Objectives
• Development of DNAzyme detection system
• Detection of ssDNA by CRISPR/Cas12a and
CRISPR/Cas14a systems
• Coupling of DNAzyme with CRISPR/Cas12a for Pd ion
detection
• Development of portable 3D device
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