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NH4OH tunes silica dots from 20 to 500 nm
Varying ammonia in a Stöber synthesis sizes silica nanoparticles from 20 to 200 nm (then 500 nm with extra TEOS), enabling core–shell TAMRA–BHQ2 quenching studies over unusually long distances.
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What size range of silica nanoparticles was achieved?
Diameters from 20 to 500 nm by tuning reactants and seed growth.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
Which reagent mainly controls 20–200 nm size?
NH4OH volume; 0.3 to 5.0 mL gave 20 to 200 nm.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
Does extra NH4OH beyond 2.0 mL keep growing particles?
No—diameter plateaus near 200 nm above 2.0 mL.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
How were 200–500 nm particles made?
After the first Stöber step, add 1.5 mL more TEOS and stir another 24 h.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
Did TEOS volume at fixed NH4OH change diameter?
Not significantly; size stayed 145 ± 14 nm.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
Did ethanol volume change size?
10–25 mL ethanol left 70 ± 18 nm particles.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
How were fluorescent SNPs made?
Add 100 μL fluorophore–APTES conjugate before TEOS, stir 24 h in the dark.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
What quenching pair was studied on the particles?
TAMRA fluorophore and BHQ2 black-hole quencher.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
What unexpected quenching result was claimed?
Significant distance-dependent quenching over a greater distance than expected.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
What other application used the fluorescent SNPs?
Ratiometric fluorescent pH-sensitive nanosensors.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified
How were <50 nm versus >50 nm particles collected?
Dialysis/freeze-dry versus 6000 rpm centrifugation.
Source: Enhanced distance-dependent fluorescence quenching using size tuneable core shell silica nanoparticles · DOI · quote verified