this is a small ppt on optical nanosensors based on my understanding.

1. OPTICAL NANOSENSORS
Sensors with at least one of its
dimension in nanoscale
Designed for making quantitative
measurements in the intracellular
environment.

2. PEBBLE
 Probe Encapsulated By Biologically
Localized Embedding.
 PEBBLEs are nano-scale sensing devices which
encapsulate an analyte-specific dye and a
reference dye inside a biologically inert matrix
 These have been developed for several
analyte, including calcium, potassium.etc..

3. CLASSIFICATION
 PEBBLEs : four types - matrices
 four types - PEBBLE delivery into the cell.
 Two types - based of their working principles
 The four types of PEBBLE matrices commonly used are:
* Polyacrylamide(PAA)
* Sol-gel
* Polydecylmethacrylate (PDMA)
* Organically modified silicates

4. DELIVERY SYSTEMS
 Liposomal delivery
 Gene gun
 Picoinjection
 Phagocytosis

6. WORKING PRINCIPLE
(a) direct measurement PEBBLEs and
(b) ion correlation PEBBLEs.
a).....
* Sense ions and small molecules
* used for sensing H+, Ca2+, Mg2+,Zn2+ and
glucose.
* some analyte lack highly selective fluorescent
indicators.

8. b)....
 consists of a silent ionophores and a
chromoionophore bound together
 Silent-high affinity towards the ion of interest
 Chromo-fluorescent behaviour
 Due to a change in pH of the chromophore as
a result of the change in the H+
concentration, the fluorescent behaviour of
the chromophore is expressed

9. ION CO-RELATION

12. ADVANTAGES
 PEBBLE :protects the cell from the dye
 protects indicator dyes from cellular interference
 multiple dyes, ionophores, and other components
can be combined to create complex sensing schemes
 Minimal physical perturbation of the cell
 Small sensor size enables rapid measurement

13. Applications

Diagnosis and monitoring of diseases.
 Study early-embryo development
 Useful for quantitative measurements in
intracellular environment.
 Measure Zinc production and localization in
brain tissue.