Neutral push-pull chromophores for nonlinear optical imaging of cell membranes

Abstract

A new class of push-pull molecules was recently identified, based on pyridine dicarboxamide as an electron acceptor group and bearing a fluorenethynyl pi-conjugated bridge. The molecules present good second and third order nonlinear properties, with a static quadratic hyperpolarisability mubeta (at 1.907 microm) of 320 x 10(-48) esu (mubeta(0) = 249 x 10(-48) esu) and a maximum two-photon absorption cross-section of 1146 GM. Starting from this generic structure, we designed a series of eight amphiphilic nonlinear probes, varying the length of the lipophilic tail and the nature of the polar head, and tested their cell membrane affinity by nonlinear optical imaging. A good membrane affinity was observed with probes bearing short alkyl chains and carbohydrate moieties as the polar head, emphasizing the importance of the lipophilic-hydrophilic balance, as well as the role of the polar head. This original approach based on carbohydrate head groups is an important advancement in the design of membrane probes, since these highly versatile functional groups confer adequate hydrophilicity and yet conserve overall molecular neutrality.

Promoting Spontaneous Second Harmonic Generation through Organogelation

“…The starting Mitsunobu reaction allowed for the isolation of intermediate 2 in a single step with a 88% yield. 23 The latter was quantitatively converted into its amino analogue 3 (see SI), which afforded the target compound 1 as a deep red solid in a 76 % yield, through a condensation with dodecyl isocyanate. Scheme 1.…”

A Theoretical Study of One- and Two-Photon Activity of D-Luciferin

“…Unlike the absorption/emission of a single photon, it is dependent on the square of the intensity of the incident light [1], which gives rise to a large spatial confinement. This means that the non-linear effect produced by the TPA process mainly occurs at the focal volume, which in turn makes this process better for fluorescence imaging [2]. The resolution increases, and better quality images are obtained compared to those obtained from conventional confocal imaging.…”

Carboxymethyl glycoside lactone (CMGL) synthons: Scope of the method and preliminary results on step growth polymerization of α-azide-ω-alkyne glycomonomers

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“…All yields were measured after silica gel chromatography using the same elution systems as in the previous sequence leading to 16. Data for 18: 13 To a solution of (N-propargylcarbamoyl)methyl -D-glucopyranoside (prepared as in ref. [9], 676 mg, 2.4 mmole) and PPh 3 (1.94 g, 7.4 mmole) in anhydrous DMF (10 mL) cooled to 0 °C was added 16 mL of a 5% HN 3 solution in toluene (see ref.…”