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Polyurethane thin films that photopolymerize and photodegrade upon exposure to light of different wavelengths are presented. The chromic response is based on two caged monomers with the ability to be activated or photocleaved with different wavelengths under single and two‐photon excitation. This material represents a dual photoresist with “positive” and “negative” tone contained in a single resist formulation and with the ability to generate complex 2D and 3D patterns.

Total synthesis and photophysical properties of PENB-DDAO, a photoactivatable 1,3-dichloro-9,9-dimethyl-9H-acridin-2(7)-one (DDAO) derivative of a far-red emitting fluorophore, are described. The photoremovable group of the DDAO phenolic function comprises a donor/acceptor biphenyl platform which allows an efficient (> or = 95%) and rapid (< 15 micros time-range) release of the fluorescent signal and displays remarkable two-photon uncaging cross sections (delta(a) x Phi(u) = 3.7 GM at 740 nm). PENB-DDAO is cell permeable as demonstrated by the triggering of cytoplasmic red fluorescent signal in HeLa cells after one-photon irradiation (lambda(exc) around 360 nm) or by the generation of a red fluorescent signal in a delineated area of a single cell after two-photon photoactivation (lambda(exc) = 770 nm).

Heterocyclic silanes containing Si-N or Si-S bonds in the ring undergo a ring opening reaction with -OH groups at the surface of porous Si nanostructures to generate -SH or -NH functional surfaces, grafted via O-Si bonds. The reaction is substantially faster (0.5-2 h at 25 °C) and more efficient than hydrolytic condensation of trialkoxysilanes on similar hydroxy-terminated surfaces, and the reaction retains the open pore structure and photoluminescence of the quantum-confined silicon nanostructures. The chemistry is sufficiently mild to allow trapping of the test protein lysozyme, which retains its enzymatic activity upon release from the modified porous nanostructure.

Different photoremovable protecting groups in the o-nitrobenzyl, phenacyl, and 2-(o-nitrophenyl)propyl series with a donor-acceptor biphenyl backbone, known to display excellent two-photon absorption cross-sections, were investigated in order to develop efficient two-photon sensitive photoremovable protecting groups. The 2-(o-nitrophenyl)propyl series was a more versatile platform to increase the two-photon sensitivity of photoremovable protecting groups, leading to the p-alkoxy and p-bisalkylamino-4-nitro-[1,1'-biphenyl]-3-yl)propyl derivatives: PENB and EANBP respectively. Those two photoremovable protecting groups are to date the best caging groups for two-photon excitation at 800 and 740 nm respectively, offering attracting perspectives in chemical biology.

The development of personalized and non-invasive cancer therapies based on new targets combined with nanodevices is a major challenge in nanomedicine. In this work, the over-expression of a membrane lectin, the cation-independent mannose 6-phosphate receptor (M6PR), was specifically demonstrated in prostate cancer cell lines and tissues. To efficiently target this lectin a mannose-6-phosphate analogue was synthesized in six steps and grafted onto the surface of functionalized mesoporous silica nanoparticles (MSNs). These MSNs were used for in vitro and ex vivo photodynamic therapy to treat prostate cancer cell lines and primary cell cultures prepared from patient biopsies. The results demonstrated the efficiency of M6PR targeting for prostate cancer theranostic.