Cellular imaging by green luminescence of Tb(III)-doped aminomodified silica nanoparticles

Luminescent nanoparticles for rapid monitoring of endogenous acetylcholine release in mice atria

“…The nanoparticles exhibit Tb(III)‐centred luminescence manifested by four bands arisen from 5 D 4 → 7 F 6 (489 nm), 5 D 4 → 7 F 5 (545 nm), 5 D 4 → 7 F 4 (582 nm), and 5 D 4 → 7 F 3 (620 nm) transitions under excitation at 330 nm (Figure a) . Luminescence intensity tends to decrease with increased acetic acid concentration (Figure a).…”

“…This two‐fold problem can be solved by a convenient surface decoration of nanoparticles doped by Tb(III) complexes that are able to give a luminescence response to acetic acid. The amino‐modification of SNs is a possible way to enhance their extracellular localization, because ammonium groups at the SNs surface facilitate their electrostatic attraction with cell membranes . Moreover, amino‐modification of SNs opens the way for their bioconjugation with target peptides, which in turn facilitates a specific binding mode of SNs with living cells .…”

“…Moreover, SNs size should be decreased for the enhancement the H‐function. The previously reported optimization of the water‐to‐surfactant ratio in the water‐in‐oil microemulsion procedure was applied in the present study for synthesis of 20‐nm size SNs. The number of amino groups per each SN was decreased from the previously reported 3500–3700 to 330 by optimization of the APTES‐to‐TEOS concentration ratio (for the detailed procedure see the Experimental section).…”

“…As mentioned above, localization of the nanosensors in atria is of particular importance for the response to acetic acid derived from the endogenous ACh during hydrolysis by endogenous AChE. The efficient adsorption of amino‐modified SNs at cell membranes is not a time‐consuming process, as it results in a great extent from electrostatic attraction, while their further cell internalization requires several hours . Thus, SNs should be efficiently bound with cell membranes to remain onto tissue samples after the incubation for 10 min followed by washing (for more detailed procedure see Experimental section).…”

“…Nanoparticulates are of particular importance in the development of sensors for ex vivo and in vivo monitoring of AChE‐catalyzed ACh hydrolysis, because nanosensor use is not invasive. Moreover, both extracellular and intracellular localization of nanosensors can be guided by their specific modifications . Previously reported Tb(III)‐doped silica nanoparticles have proved to be efficient nanosensors for monitoring AChE‐catalyzed hydrolysis of ACh in cuvettes due to their efficient H‐sensing function .…”