7/19/2021

1

05/12/2015

7/19/2021

2

SELEX

Aptamer and kind of

Aptamer in dignosis

Aptamer in treatment

Aptamer in drug delivery

Aptamer VS Antibody

What is aptamer?

A tamers (from the Latin aptus -meaning fit, and Greek meros -meaning part) are oligonucleic acid or peptide molecules that bind to a specific target molecule.

Crystallogrphic imageshowing an

RNA aptamer(green)

binding to its target

molecule

1

7/19/2021

3

More specifically, aptamers can be classified as:

Peptid

RNA

DNA

2

Bacterial protein thioredoxin A

3

7/19/2021

4

Modified phosphate backbones4

SELEX(Systematic evolution of ligands by exponential enrichment)

5

7/19/2021

5

Aptamer VS AntibodyAntibodyAptamer

Cell culture & animal needExpensive

Laboure expensive

Chemical synthesisInexpensive

easyprod

ucti

on

6 monthsSELEX8 weeks

Dis

cove

ry

tim

e

Difficult for apply to harsh conditionKipping problem with potential loos of

functions

Stable in harsh conditionNo loos of activity

stab

ilit

y

Difficult for chemical modificationEasy for chemical modificationFluorecent, affinity tag…

mod

ific

atio

n

Large size(150 KDa )Difficult membrane penetration, long

blood residence

Small size(>30 KDa )Easy membrane penetration, short

blood residence

size

6

AntibodyAptamer

Limited(6 months)Long(several years in frozen)

She

lfli

fe

Can cause immune response if used as a drug

No intrinsic immune response

Invi

voco

mpl

icat

ion

Good affinityHigh affinity

Aff

init

y

Good specificityHigh specificity

spec

ific

ity

Limited to targets that produce an immune response

Can be produced against almost anything

Tar

get

reng

e

7

7/19/2021

6

8

Clinical diagnosis need

aptamer because of

Small size

Stable folding structure

economy

9

7/19/2021

7

Molecular imaging

The field of molecular imaging, “the visualization, characterization and measurement ofbiological processes at the molecular and cellular levels in humans and other livingsystems”

Commonly used molecular imaging modalities include molecular magnetic resonanceimaging (MRI), bioluminescence, fluorescence, targeted ultrasound, single photonemission computed tomography (SPECT), and positron emission tomography (PET).

Noninvasive molecular imaging of molecular markers of various diseases can allow formuch earlier diagnosis, earlier treatment, and better prognosis

10

aptamer-based optical imaging

Direct Targeting

with Aptamers

Aptamer-Based

Activatable Probes

11

7/19/2021

8

Integrin αvβ3Prostate-specific membrane antigen (PSMA)

Direct Targeting with Aptamers

Aptamer-Based Activatable Probes

12

MR imaging–based molecular imaging

TARGETED ULTRASOUND

SPECT AND PET IMAGING

13

7/19/2021

9

Aptamer-based sensors(Aptasensors)

Electrochemical

Aptasensors

Optical Aptasensors

Mass-sensitive

Aptasensors

14

Electrochemical aptasensores

Optical aptasensore

Mass-sensitive aptasensor

15

7/19/2021

10

biomarker detection:analysis of biomarkers in blood, urine and other body fluids:

Thrombin, IFN gamma

cancer clinical testing:Detection and identification of tumor cells rely on the identificationof some markers that appear only on the tumor cells such aslymphoma (Ramos) cells, leukemia cells

detection of infectious microorganisms and viruses:

16

AptaBiD or Aptamer-Facilitated Biomarker Discovery

AptaBiD or Aptamer-Facilitated Biomarker Discovery is a technology for biomarker discovery.

AptaBiD is based on multi-round generation of an aptamer or a pool of aptamers for differential molecular targets on the cells which facilitates exponential detection of biomarkers.

It involves three major stages:

(i) differential multi-round selection of aptamers for biomarker of target cells;(ii) aptamer-based isolation of biomarkers from target cells(iii) mass spectrometry identification of biomarkers

17

7/19/2021

11

Salient Features of Therapeutic Aptamers18

Aptamers in Microbial Infections

Aptamers in Viral Infections

Aptamers in Cardiovascular

Diseases

Aptamers in Autoimmune Diseases

and Neurological Diseases

DNA aptamers AT-27, AT-33, AT-36 and AT-49 inhibit the cytotoxic activity of α-toxin from Staphylococcus aureus .

Aptamer entitled NK2 against membrane proteins that are present on the surface of the virulent M. tuberculosis stain H37Rv.

HIV-1 Integrase

Hepatitis C virus IE2

Human Immunodeficiency Virus-1

HIV-1 Reverse Transcriptase

HIV-1 Integrase

Thrombin Nu172

von Willebrand factor ARC1779Von Willbrand disease and Acut coronary syndrom

aptamer Apt21-2 against human Interleukin-17 in multiple sclerosis

Alzeheimer’s diseas anti-BACE1 aptamer

19

7/19/2021

12

20

An Aptamer–Doxorubicin Physical Conjugate asa Novel Targeted Drug-Delivery Platform21

7/19/2021

13