Bioprinting is expected to be a revolutionary technology for application in medicine, bringing hope to countless patients. For a long time, many patients have been experiencing a lack of suitable organs for transplantation, which eventually lead to loss of lives. Bioprinting technology can integrate cells, proteins, cytokines, and other supporting materials, such as biomaterials and hydrogels, to produce biomedical devices with biological functions. However, no bioprinting medical devices have been approved by the National Medical Products Administration, with specific registration and regulatory requirements for bioprinting medical devices still needing to be explored. To standardize the Bioprinting Medical Devices Special Requirements for Quality Management System, Chinese experts in relevant fields were organized to formulate this expert consensus.
A strain sensing structure with high gauge factors (GFs) is designed by engineering channel cracks in a gold thin film. The developed strain sensors possess GFs as high as 200 (ε < 0.5%), 1000 (0.5% < ε < 0.7%), and even exceeding 5000 (0.7% < ε < 1%).
In this paper, a series of silver-deposited TiO2 (Ag−TiO2) nanoparticles (NPs) with a varying content of Ag were prepared by a photoreduction method and were attempted to serve as SERS-active substrates for the first time. SERS signals of 4-MBA molecules adsorbed on Ag−TiO2 NPs were further enhanced considerably relative to those enhancements on pure TiO2 NPs. The surface-deposited Ag on TiO2 can inject additional electrons into molecules adsorbed on the TiO2 surface through the conduction band of TiO2 NPs because of plasmon resonance absorption of Ag under incident visible laser, besides the intrinsic TiO2-to-molecule charge-transfer (CT) contribution. The two contributions mentioned are responsible for the whole SERS intensity of the molecules adsorbed on Ag−TiO2 NPs. This work is valuable in developing nanosized TiO2 used as a promising, nontoxic and biologically compatible SERS-active substrate as well as in studying the CT mechanism between Ag and TiO2 for potential photoelectrochemical applications.
Phosphenic isocyanate (O2PNCO), a novel phosphorus-containing small molecule has been generated by thermolysis of a dioxaphospholane-based precursor. The characterization of O2PNCO with IR and UV-vis spectroscopy in solid N2 and Ar matrices at 10 K is supported by the calculations at the CCSD(T)-F12a/cc-pVTZ-F12 level of theory. Upon irradiation at 193 nm, O2PNCO decomposes yielding CO2, OPN, CO, ˙NO, and ˙PO, in which the possible formation of two exotic intermediates O2PN and OPNO in the triplet ground state has been proposed.
Abstract The simplest diphosphene HPPH and isomeric diphosphinyldene PPH 2 features prototype phosphorus‐phosphorus multiple bonding properties that have been of long‐standing interest in main‐group chemistry. Herein, we report the observation of cis ‐HPPH, trans ‐HPPH, and PPH 2 among the respective laser photolysis products of phosphine (PH 3 ) and diphosphine (P 2 H 4 ) in solid N 2 ‐ and Ar‐matrices at 10 K. The identification of these P 2 H 2 isomers with matrix‐isolation IR and UV/Vis spectroscopy is supported by D‐isotope labeling and the quantum chemical calculations at the CCSD(T)‐F12a/cc‐pVTZ‐F12 level using configuration‐selective vibrational configuration interaction theory (VCI). Bonding analyses suggest that the two conformers of HPPH contain standard PP double bonds, whereas, PPH 2 resembles P 2 in having partial PP triple bond due to the H 2 P←P π bonding interaction.
Recently, surface-enhanced Raman scattering (SERS) research based on semiconductor TiO2 has received increasing attention. However, the practical application of TiO2 SERS-active substrates has been hampered due to their lower surface performance and detection sensitivity. Here we report a new strategy to enhance the SERS activity of TiO2 nanoparticles (NPs) by means of formation of a mesoporous framework via reductive calcination of polymer coated nanocrystals. The 4-mercaptobenzoic acid (4-MBA) probe molecules on the mesoporous TiO2 substrate exhibit larger SERS enhancement compared with that on the ordinary TiO2 NP substrate; this considerable SERS enhancement mainly stems from the contributions of rich surface active sites of mesoporous TiO2, which can provide more effective adsorption sites for the molecules and promote the charge transfer between the substrate and the adsorbed molecule, and thus remarkably enhance SERS signals. On the mesoporous TiO2, a detection limit of 4-MBA as low as 1 × 10-8 mol L-1 can be achieved, which is the highest sensitivity among those reported for semiconducting substrates and even comparable with those of noble metal substrates. And, it is proved that the mesoporous TiO2 substrates are characterized by high stability and self-cleaning properties, and can be repeatedly used in SERS detection without losing their activity.
Surface-enhanced Raman scattering from molecules adsorbed on TiO2 nanoparticles has been observed. This is attributed to the dominant contribution of the TiO2-to-molecule charge-transfer mechanism. The charge-transfer process is largely dependent on the intrinsic nature of the adsorbed molecules and the surface properties of the semiconductor. Both the stronger electron attracting ability of groups para- to the mercapto group bonded with TiO2 surface and the plentiful surface states of TiO2 nanoparticles are favorable to TiO2-to-molecule charge-transfer and SERS for molecules adsorbed on TiO2.
Abstract Two sterically congested 2,2′:6′,2″‐terpyridine‐based ligands LA and LB, composed of asymmetrically contiguous terpyridine units, are designed and synthesized for metallo‐supramolecular architectures. The significant advantage of this design is that the terpyridines in these ligands have different chemical environments and show a selective coordination ability with each other. For ditopic ligand LA, the self‐assembly with Zn(II), Cd(II), and Fe(II) gave the rhombic dimers, which have the same sets of terpyridine signals as ligand LA. The self‐assembly behavior of tritopic ligand LB with Cd(II) and Zn(II) are observed for discrete tetramers under thermodynamic control, whereas ligand LB and Fe(II) are assembled to generate a mixture of tetramer, hexamer, and octamer, which are successfully isolated using regular chromatographic separation. Moreover, the sterically congested ligands and metal ions formed stable intermediates to drive the formation of discrete structures, which is also proved by mixing LB and Cd(II) with a precise stoichiometric ratio of 1:1. These supramolecular complexes are thoroughly characterized by NMR spectroscopy, electrospray ionization‐mass spectrometry, and 2D traveling‐wave ion mobility‐mass spectrometry. This conceptually new design of sterically congested ligands provides a novel strategy for precisely controlled supramolecular complexes with diverse architectures.
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