Anti-Collagen Type I polyclonal antibody

Structural modification of a ligand is an effective way to improve the catalytic activity of molecular catalysts for photocatalytic CO, reduction. In this study, we designed and synthesized three tripodal ligands with different conjugate groups (L-1 = tris{2-[(9' - anthrylmethyl)amino)ethyl}amine, L-2 = tris{2-[(1'-naphthylmethyl)amino]ethyl}amine, L-3 = tris[2-(benzylamino)ethyl]amine), and their corresponding mononuclear cobalt complexes, [CoL1(OH)]ClO4 (1), [CoL2(OH)]ClO4 (2), and [CoL3(OH)]ClO4 (3). Control experiments showed that 1 and 2 possess higher efficiency than 3 for the photocatalytic CO2-to-CO conversion, with TON and TOF for CO of 58 000 and 1.61 s(-1) for 1, and 49 200 and 1.37 s(-1) for 2, respectively, greatly higher than those of 3. Compounds 1 and 2 also display higher CO selectivity (>= 97%) than 3. Control experiments and DFT calculations revealed that the excellent catalytic performances of 1 and 2 can be ascribed to the extended conjugation substituent in L-1 and L-2, which endows the Co-II catalytic center with low reduction potential, accelerates the intermolecular electron transfer, and thus dramatically boosts the CO2-to-CO conversion. This study demonstrates that the improvement of the electron transfer between photosensitizer and catalysts is the key for enhancing the activity of catalyst for CO2-to-CO conversion.

We have shown that materials other than hydrogels commonly used in tissue engineering can be effective in enabling differentiation of dental pulp stem cells (DPSC). Here we demonstrate that a hydrophobic elastomer, polyisoprene (PI), a component of Gutta-percha, normally used to obturate the tooth canal, can also be used to initiate differentiation of the pulp. We showed that PI substrates without additional coating promote cell adhesion and differentiation, while their moduli can be easily adjusted either by varying the coating thickness or incorporation of inorganic particles. DPSC plated on those PI substrates were shown, using SPM and hysitron indentation, to adjust their moduli to conform to differentially small changes in the substrate modulus. In addition, optical tweezers were used to separately measure the membrane and cytoplasm moduli of DPSC, with and without Rho kinase inhibitor. The results indicated that the changes in modulus were attributed predominantly to changes within the cytoplasm, rather than the cell membrane. CLSM was used to identify cell morphology. Differentiation, as determined by qRT-PCR, of the upregulation of OCN, and COL1 alpha 1 as well as biomineralization, characterized by SEM/EDAX, was observed on hard PI substrates in the absence of induction factors, i.e. dexamethasone, with moduli 3-4 MPa, regardless of preparation. SEM showed that even though biomineralization was deposited on both spun cast thin PI and filled thick PI substrates, the minerals were aggregated into large clusters on thin PI, and uniformly distributed on filled thick PI, where it was templated within banded collagen fibers. Statement of Significance This manuscript demonstrates the potential of polyisoprene (PI), an elastomeric polymer, for use in tissue engineering. We show how dental pulp stem cells adjust their moduli continuously to match infinitesimally small changes in substrate mechanics, till a critical threshold is reached when they will differentiate. The lineage of differentiation then becomes a sensitive function of both mechanics and morphology for a given chemical composition. Since PI is a major component of Gutta-percha, the FDA approved material commonly used for obturating the root canal, this work suggests that it can easily be adapted for in vivo use in dental regeneration. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.