Spherical and rod shaped mesoporous silica nanoparticles for cancer-targeted and photosensitizer delivery in photodynamic therapy.

Mesoporous silica nanoparticles (MSNPs) have attracted much attention in many biomedical applications. One of the fields in which smart functional nanosystems have found wide application is cancer treatment. Here, we present new silica nanoparticle-based systems which have been explored as efficient vehicles to transport and deliver photosensitizers (PSs) into tumor tissues during photodynamic therapy (PDT). In this work, we report the preparation, characterization, and in vitro studies of distinct shaped MSNPs grafted with S-glycoside porphyrins (Pors). The ensuing nanomaterials were fully characterized, and their properties as third-generation PSs for PDT against two bladder cancer cell lines, HT-1376 and UM-UC-3, were examined. The best uptake results were obtained for MSNP-PS2, while MSNP-PS1 showed the lowest cellular uptake among the nanocarriers tested, but revealed the best phototoxicity in both cancer cells. Overall, the phototoxicity was higher with MSNPs than with mesoporous silica nanorods (MSNRs) and higher uptake and phototoxicity were consistently observed in UM-UC-3 rather than in HT-1376 cancer cells.

Recent Progress in Phthalocyanine-Polymeric Nanoparticle Delivery Systems for Cancer Photodynamic Therapy.

This perspective article summarizes the last decade's developments in the field of phthalocyanine (Pc)-polymeric nanoparticle (NP) delivery systems for cancer photodynamic therapy (PDT), including studies with at least in vitro data. Moreover, special attention will be paid to the various strategies for enhancing the behavior of Pc-polymeric NPs in PDT, underlining the great potential of this class of nanomaterials as advanced Pcs' nanocarriers for cancer PDT. This review shows that there is still a lot of research to be done, opening the door to new and interesting nanodelivery systems.

Targeting Cancer Cells with Photoactive Silica Nanoparticles.

This review highlights recent advances in the preparation of silica nanoparticles (SNPs) functionalized with porphyrins and phthalocyanines for application in cancer photodiagnostic and photodynamic therapy (PDT). The use of photosensitizer-SNP formulations has emerged recently as a new nanomedicine for cancer research owing to their unique physicochemical properties, which make them useful for photo-biomedical applications. In order to study their photobiological properties, diverse chemical strategies involving covalent and non-covalent bonding have been used to load photosensitizers in/on SNPs.

Steric vs. electronic effects in the Lactobacillus brevis ADH-catalyzed bioreduction of ketones.

Lactobacillus brevis ADH (LBADH) is an alcohol dehydrogenase that is commonly employed to reduce alkyl or aryl ketones usually bearing a methyl, an ethyl or a chloromethyl as a small ketone substituent to the corresponding (R)-alcohols. Herein we have tested a series of 24 acetophenone derivatives differing in their size and electronic properties for their reduction employing LBADH. After plotting the relative activity against the measured substrate volumes we observed that apart from the substrate size other effects must be responsible for the activity obtained. Compared to acetophenone (100% relative activity), other small substrates such as propiophenone, α,α,α-trifluoroacetophenone, α-hydroxyacetophenone, and benzoylacetonitrile had relative activities lower than 30%, while medium-sized ketones such as α-bromo-, α,α-dichloro-, and α,α-dibromoacetophenone presented relative activities between 70% and 550%. Moreover, the comparison between the enzymatic activity and the obtained final conversions using an excess or just 2.5 equiv. of the hydrogen donor 2-propanol, denoted again deviations between them. These data supported that these hydrogen transfer (HT) transformations are mainly thermodynamically controlled. For instance, bulky α-halogenated derivatives could be quantitatively reduced by LBADH even employing 2.5 equiv. of 2-propanol independently of their kinetic values. Finally, we found good correlations between the IR absorption band of the carbonyl groups and the degrees of conversion obtained in these HT processes, making this simple method a convenient tool to predict the success of these transformations.

Synthesis of enantiopure fluorohydrins using alcohol dehydrogenases at high substrate concentrations.

The use of purified and overexpressed alcohol dehydrogenases to synthesize enantiopure fluorinated alcohols is shown. When the bioreductions were performed with ADH-A from Rhodococcus ruber overexpressed in E. coli, no external cofactor was necessary to obtain the enantiopure (R)-derivatives. Employing Lactobacillus brevis ADH, it was possible to achieve the synthesis of enantiopure (S)-fluorohydrins at a 0.5 M substrate concentration. Furthermore, due to the activated character of these substrates, a huge excess of the hydrogen donor was not necessary.