Molecular Diagnostics
PhD. Hoa Quang LE
School of Biotechnology and
Food Technology
Hanoi University of Science
and Technology
Some success stories
Glucose sensor
→ Diabetic patients can monitor blood glucose at home
Glucose sensor
Pregnancy testing
Pregnancy testing

Human chorionic gonadotropin (hCG) is a glycopeptide
hormone produced by the placenta during pregnancy.

The appearance and rapid rise in the concentration of
hCG in the woman's urine makes it a good pregnancy
marker.

Usually, concentration of hCG in urine is at least 25
mIU/ml as early as seven to ten days after conception.

The concentration increases steadily and reaches its
maximum between the eighth and eleventh weeks of
pregnancy.
Pregnancy testing
Molecular diagnostics

Diagnosis of infectious diseases



Culture methods

Immunological methods (antigen detection, antibody
detection): specific interactions between antibody and
antigen

Nucleic acid-based methods (PCR, NASBA, LAMP):
specific binding between DNA or RNA molecules
Culture methods

Use media for isolation and identification of pathogenic
organisms. Useful for antimicrobial sensitivity test.

Different types of media:
•
Enriched media: high nutritive value to promote growth
•
Selective media: allow only needed bacteria to growth
•
Indicator media: to distinguish one microorganism type
from another growing on the same media
Culture methods

Evaluation based on:
•
Colony morphology (shape, size, color, edge of colony)
•
Pigment production
•


ELISA (Enzyme Linked Immunosorbent
Assay)

ELISA involves:
•
the reaction of an antibody with an antigen and a
detection system to determine if a reaction has
occurred.
•
binding of the test molecule or organism to a solid
support (e.g. micro titer plate).
ELISA to detect antigen

capture antibody, directed against
antigenic protein, is linked to a solid support

clinical sample is added, the antigen, if
present, will be capture by the bound antibody

washing to remove unbound molecules

addition of second antibody which will be bind to the antigen. This
antibody is linked to an enzyme

washing to remove unbound molecules

addition of a colorless substrate → color product → positive result