Anilinomethylrhodamines: pH Sensitive Probes with Tunable Photophysical Properties by Substituent Effect

Best, Quinn A.; Liu, Chuangjun; Hoveln, Paul D. van; McCarroll, Matthew E.; Scott, Colleen N.

doi:10.1021/jo401323g

Cited by 45 publications

(28 citation statements)

References 30 publications

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“…Further protonation occurs but is not observed as a separate event by either UV-vis absorption or fluorescence. This is consistent with previous AMR derivatives [12] but differs from the AnMR series where two separate events were observed in the fluorescence and UV-vis absorption measurements upon decreasing the pH of the solution [14]. An equilibrium constant between the spiro-cyclic form and the open-form can be approximated at half-max of the pH dependent absorbance curve, which we will conveniently refer to as the pK a of the individual cAMR derivative.…”

Section: Resultssupporting

confidence: 89%

Cycloalkyl-AminoMethylRhodamines: pH Dependent Photophysical Properties Tuned by Cycloalkane Ring Size

et al. 2015

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A series of fluorescent pH probes based on the spiro-cyclic rhodamine core, aminomethylrhodamines (AMR), was synthesized and the effect of cycloalkane ring size on the acid/base properties of the AMR system was explored. The study involved a series of rhodamine 6G (cAMR6G) and rhodamine B (cAMR) pH probes with cycloalkane ring sizes from C-3 to C-6 on the spiro-cyclic amino group. It is known that the pKa value of cycloalkylamines can be tuned by the different ring sizes in accordance with the Baeyer ring strain theory. Smaller ring amines have lower pKa value, i.e. they're less basic, such that the relative order in cycloalkylamine basicity is: cyclohexyl>cyclopentyl>cyclobutyl>cyclopropyl. Herein, it was found that the pKa values of the cAMR and cAMR6G systems can also be predicted by Baeyer ring strain theory. The pKa values for the cAMR6G series were shown to be higher than the cAMR series by a value of approximately 1.

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Section: Resultssupporting

confidence: 89%

Cycloalkyl-AminoMethylRhodamines: pH Dependent Photophysical Properties Tuned by Cycloalkane Ring Size

et al. 2015

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“…Dyes of the rhodamine family are employed for sensing owing to their photophysical properties, including large quantum yield, absorption, and photostability [33]. The molecular fluorescence is reduced or enhanced when the molecule undergoes structural changes in the presence of the target, particularly when the pH around the molecule is changed [34,35]. Rhodamine 6G is known as a stable molecule whose luminescence is reduced in highly alkaline environments.…”

Section: Resultsmentioning

confidence: 99%

Gain-Based Mechanism for pH Sensing Based on Random Lasing

et al. 2017

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Here, we investigate the mechanism of a random-lasing-based sensor which shows pH sensitivity exceeding by 2 orders of magnitude that of a conventional fluorescence sensor. We explain the sensing mechanism as related to gain modifications and lasing-threshold nonlinearities. A dispersive diffusive lasing theory matches the experimental results well, and it allows us to predict the optimal sensing conditions and a maximal sensitivity as large as 200 times that of an identical fluorescence-based sensor. The lack of complex alignment and the high sensitivity make this mechanism promising for future biosensing applications.

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“…We previously reported the use of rhodamine-lactams for imaging of lysosomal acidity and lysosomal pH based tumor imaging. [13][14][15][16][17][18][19][20][21][22] Herein rhodamine-lactams were conjugated with bacterium-homing entities to envelope rhodamine-lactams within bacteria for reporting phagolysosomal acidity during bacterial phagocytosis.…”

Section: Resultsmentioning

confidence: 99%

Optical Tracking of Phagocytosis with an Activatable Profluorophore Metabolically Incorporated into Bacterial Peptidoglycan

Tian

et al. 2015

Anal. Chem.

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Phagocytosis is critical for immunity against pathogens. Prior imaging using dye-labeled synthetic beads or green fluorescent protein-expressing bacteria is limited by "always-on" signals which compromise discerning phagocytosed particles from adherent particles. Targeting cellular internalization of pathogens into acidic phagolysosomes, we herein report "turn-on" fluorescence imaging of phagocytosis with viable bacteria featuring peptidoglycans covalently modified with rhodamine-lactam responsive to acidic pH. Culturing of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with d-lysine conjugated rhodamine-lactam and fluorescein isocyanate (FITC) leads to efficient metabolic incorporation of FITC and rhodamine-lactam into bacterial peptidoglycan. E. coli and S. aureus become red-emissive upon phagocytosis into Raw 264.7 macrophages. With FITC as the reference signal, the mono- and dual-color emission allow efficient in situ distinction of ingested bacteria from extracellular bacteria. Given the ease of optical peptidoglycan labeling, the prevalence of microbial peptidoglycan and preservation of microbial surface landscape, this approach would be of use for investigation on microbial pathogenesis and high-throughput screening of immunomodulators of phagocytosis.

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Anilinomethylrhodamines: pH Sensitive Probes with Tunable Photophysical Properties by Substituent Effect

Cited by 45 publications

References 30 publications

Cycloalkyl-AminoMethylRhodamines: pH Dependent Photophysical Properties Tuned by Cycloalkane Ring Size

Cycloalkyl-AminoMethylRhodamines: pH Dependent Photophysical Properties Tuned by Cycloalkane Ring Size

Gain-Based Mechanism for pH Sensing Based on Random Lasing

Optical Tracking of Phagocytosis with an Activatable Profluorophore Metabolically Incorporated into Bacterial Peptidoglycan

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