Cellular Uptake and Movement in 2D and 3D Multicellular Breast Cancer Models of Fructose-Based Cylindrical Micelles That Is Dependent on the Rod Length

While the shape effect of nanoparticles on cellular uptake has been frequently studied, no consistent conclusions are available currently. The controversy mainly focuses on the cellular uptake of elongated (i.e., filaments or rod-like micelles) as compared to spherical (i.e., micelles and vesicles) nanoparticles. So far, there is no clear trend that proposes the superiority of spherical or nonspherical nanoparticles with conflicting reports available in the literature. One of the reasons is that these few reports available deal with nanoparticles of different shapes, surface chemistries, stabilities, and aspects ratios. Here, we investigated the effect of the aspect ratio of cylindrical micelles on the cellular uptake by breast cancer cell lines MCF-7 and MDA-MB-231. Cylindrical micelles, also coined rod-like micelles, of various length were prepared using fructose-based block copolymers poly­(1-<i>O</i>-methacryloyl-β-d-fructopyranose)-<i>b</i>-poly­(methyl methacrylate). The critical water content, temperature, and stirring rate that trigger the morphological transition from spheres to rods of various aspect ratios were identified, allowing the generation of different kinetically trapping morphologies. High shear force as they are found with high stirring rates was observed to inhibit the formation of long rods. Rod-like micelles with length of 500–2000 nm were subsequently investigated toward their ability to translocate in breast cancer cells and penetrate into MCF-7 multicellular spheroid models. It was found that shorter rods were taken up at a higher rate than longer rods

Polypeptide-Grafted Nanodiamonds for Controlled Release of Melittin to Treat Breast Cancer

A peptide vector consisting of nanodiamonds (NDs) and PEGylated polyglutamic acid (ND@PLGPEG-<i>co</i>-PLGA) has been designed and developed. The negative charges at the surface of the vector were exploited to bind a positively charged peptide drug melittin via electrostatic interaction. The surface was saturated when the weight ratio of ND@PLGPEG-<i>co</i>-PLGA to melittin (MEL) was 5 to 1. The desorption of melittin from the surface was controlled by pH, with almost no melittin released from the nanoparticles under physiological pH conditions in 2 days. However, steady release was detected in an acidic environment. The preserved structure and activity of bound melittin were demonstrated by the HPLC and 2D MCF-7 cell culture models, respectively. The bound melittin exhibited improved toxicity toward MCF-7 cells dependent on the concentration of MEL in NDs. Our results suggested that the negatively charged polymer-coated NDs were able to release the cargo upon exposure to breast cancer cells

Blue Light Sensitive Dyes for Various Photopolymerization Reactions: Naphthalimide and Naphthalic Anhydride Derivatives.

Novel naphthalimide derivatives (or naphthalic anhydride derivatives) have been prepared and combined with an iodonium salt, <i>N</i>-vinylcarbazole, amines or 2,4,6-tris­(trichloromethyl)-1,3,5-triazine to produce radicals and cations upon exposure to low intensity blue lights (e.g., a household blue LED bulb). The photochemical mechanisms are studied by electron spin resonance spin trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques. The naphthalimide derivatives (ND4) or the naphthalic anhydride derivative (ND10) based photoinitiating systems are particularly efficient for cationic, radical and thiol–ene photopolymerizations; the synthesis of interpenetrated polymer networks IPNs can also be easily carried out. Compared to camphorquinone/amine or camphorquinone/iodonium salt, the new proposed combinations appear as highly versatile and high performance visible light photoinitiating systems. Some of these photoinitiating systems can also be used for UV LED irradiations (e.g., 365, 385, or 395 nm)

Copper Complexes in Radical Photoinitiating Systems: Applications to Free Radical and Cationic Polymerization upon Visible LEDs

Three copper complexes (E1, G1, and G2) with different ligands in combination with an iodonium salt (and optionally another additive) were used to generate radicals upon soft visible light exposure (e.g., polychromatic visible light from a halogen lamp, laser diodes at 405 and 457 nm, LEDs at 405 and 455 nm). This approach can be worthwhile and versatile to initiate free radical photopolymerization, ring-opening cationic photopolymerization, and the synthesis of interpenetrating polymer networks. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry, electron spin resonance spin trapping, steady state photolysis, and laser flash photolysis techniques. The photoinitiation ability of the copper complexes based photoinitiating systems are evaluated using real-time Fourier transform infrared spectroscopy. G1 and G2 are better than the well-known camphorquinone (CQ)-based systems (i.e., TMPTA conversion = 18%, 35%, 48%, and 39% with CQ/iodonium salt, CQ/amine, G1/iodonium salt, and G2/iodonium salt, respectively; halogen lamp exposure). Interestingly, some of these systems are also better than the well-known type I phosphine oxide photoinitiator (BAPO) clearly showing their high performance. These copper complexes can be used as highly efficient catalysts in photoredox catalysis

Variations on the Benzophenone Skeleton: Novel High Performance Blue Light Sensitive Photoinitiating Systems

Newly developed benzophenone derivatives in combination with an iodonium salt (and optionally <i>N</i>-vinylcarbazole) or amines have been used as photoinitiating systems. Their abilities to initiate cationic photopolymerization of epoxides and/or radical photopolymerization of acrylates under very soft visible halogen lamp, LED and laser diodes irradiations have been investigated. One of them (BPD5) is particularly efficient for the cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure and leads to the formation of an interpenetrated polymer network IPN upon the house hold blue LED bulb exposure (1 min for getting tack free coatings). The performances attained with some derivatives are better than those obtained with camphorquinone, used as reference photoinitiator, highlighting their high initiating abilities. These systems can be useful to overcome the oxygen inhibition for very low light intensity. The photochemical mechanisms are studied by molecular orbital calculations, fluorescence, cyclic voltammetry, laser flash photolysis, electron spin resonance spin trapping, and steady state photolysis techniques

Cationic and Thiol–Ene Photopolymerization upon Red Lights Using Anthraquinone Derivatives as Photoinitiators

Anthraquinone derivatives in combination with an iodonium salt (and optionally <i>N</i>-vinylcarbazole) have been used as photoinitiating systems. One of them (Oil Blue N) that is particularly efficient for cationic, IPN, and thiol–ene polymerization upon red lights (laser diode at 635 nm or household red LED bulb at 630 nm) belongs to the very few systems available at this long wavelength in such experimental conditions (low light intensity in the 10–100 mW/cm² range). Their abilities to initiate the cationic photopolymerization of epoxides or vinyl ethers under very soft halogen lamp irradiation have been also investigated. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, and electron spin resonance spin trapping techniques

Julolidine or Fluorenone Based Push–Pull Dyes for Polymerization upon Soft Polychromatic Visible Light or Green Light.

Two push–pull dyes (a julolidine derivative <b>DCJTB</b> and a fluorenone-<i>co</i>-amino phenyl derivative <b>h-B3FL</b>), incorporated in multicomponent photoinitiating systems have been investigated for the cationic polymerization of epoxides or the radical polymerization of acrylates under visible light irradiations (household halogen lamp or green laser diode at 532 nm). The <b>DCJTB/</b>iodonium salt (and optionally <i>N</i>-vinylcarbazole) based systems are pretty efficient for the cationic polymerization of epoxides. Both dyes, when combining with an amine and 2,4,6-<i>tris</i>(trichloromethyl)-1,3,5-triazine, exhibit a good efficiency in the radical polymerization of acrylates. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques

Design of High Performance Photoinitiators at 385–405 nm: Search around the Naphthalene Scaffold

Novel naphthalene derivatives have been designed to be used as versatile photoinitiators upon a laser diode (405 nm), a polychromatic halogen lamp, or an UV LED (385 nm) exposure. The reactive species produced from photoinitiating systems based on one particular naphthalene derivative (NA3) and an iodonium salt, <i>N</i>-vinylcarbazole, an amine or 2,4,6-<i>tris</i>(trichloromethyl)-1,3,5-triazine were particularly efficient for cationic, radical, IPN and thiol–ene photopolymerizations upon low light intensity exposure. The best proposed systems exhibit a higher efficiency than references systems for visible lights (i.e., camphorquinone CQ-based photoinitiating systems). The mechanisms for the photochemical generation of reactive species (i.e., radicals and cations) were studied by electron spin resonance spin-trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques

Structure Design of Naphthalimide Derivatives: Toward Versatile Photoinitiators for Near-UV/Visible LEDs, 3D Printing, and Water-Soluble Photoinitiating Systems

Seven naphthalimide derivatives (NDP1–NDP7) with different substituents have been designed as versatile photoinitiators (PIs), and some of them when combined with an iodonium salt (and optionally <i>N</i>-vinylcarbazole) or an amine (and optionally chlorotriazine) are expected to exhibit an enhanced efficiency to initiate the cationic polymerization of epoxides and the free radical polymerization of acrylates under different irradiation sources (i.e., the LED at 385, 395, 405, 455, or 470 nm or the polychromatic visible light from the halogen lamp). Remarkably, some studied naphthalimide derivative based photoinitiating systems (PIS) are even more efficient than the commercial type I photoinitiator bisacylphosphine oxide and the well-known camphorquinone-based systems for cationic or radical photopolymerization. A good efficiency upon a LED projector at 405 nm used in 3D printers is also found: a 3D object can be easily created through an additive process where the final object is constructed by coating down successive layers of material. As another example of their broad potential, a NDP compound enveloped in a cyclodextrin (CD) cavity, leads to a NDP–CD complex which appears as a very efficient water-soluble photoinitiator when combined with methyldiethanol amine to form a hydrogel. The high interest of the present photoinitiator (NDP2) is its very high reactivity, allowing synthesis in water upon LED irradiation as a green way for polymer synthesis.The structure/reactivity/efficiency relationships as well as the photochemical mechanisms associated with the generation of the active species (radicals or cations) are studied by different techniques including steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin-trapping methods

Structural Effects in the Indanedione Skeleton for the Design of Low Intensity 300–500 nm Light Sensitive Initiators.

Newly synthesized indanedione derivatives combined with an iodonium salt, <i>N</i>-vinylcarbazole, amine, phenacyl bromide, or 2,4,6-tris­(trichloromethyl)-1,3,5-triazine have been used as photoinitiating systems upon very low visible light intensities: blue lights (e.g., household blue LED bulb at 462 nm) or even a halogen lamp exposure. One of them (ID2) is particularly efficient for cationic, radical and thiol–ene photopolymerizations as well as for the synthesis of interpenetrated polymer networks (IPNs). It can be useful to overcome the oxygen inhibition. ID2 based photoinitiating systems can also be selected for the reduction of Ag⁺ and the in situ formation of Ag(0) nanoparticles in the synthesized polymers. The (photo)­chemical mechanisms are studied by electron spin resonance spin trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques