A multifunctional platform is reported for synergistic therapy with controlled drug release, magnetic hyperthermia, and photothermal therapy, which is composed of graphene quantum dots (GQDs) as caps and local photothermal generators and magnetic mesoporous silica nanoparticles (MMSN) as drug carriers and magnetic thermoseeds. The structure, drug release behavior, magnetic hyperthermia capacity, photothermal effect, and synergistic therapeutic efficiency of the MMSN/GQDs nanoparticles are investigated. The results show that monodisperse MMSN/GQDs nanoparticles with the particle size of 100 nm can load doxorubicin (DOX) and trigger DOX release by low pH environment. Furthermore, the MMSN/GQDs nanoparticles can efficiently generate heat to the hyperthermia temperature under an alternating magnetic field or by near infrared irradiation. More importantly, breast cancer 4T1 cells as a model cellular system, the results indicate that compared with chemotherapy, magnetic hyperthermia or photothermal therapy alone, the combined chemo-magnetic hyperthermia therapy or chemo-photothermal therapy with the DOX-loaded MMSN/GQDs nanosystem exhibits a significant synergistic effect, resulting in a higher efficacy to kill cancer cells. Therefore, the MMSN/GQDs multifunctional platform has great potential in cancer therapy for enhancing the therapeutic efficiency.
The crystal structure of a new bismuth-based light-absorbing material for the application in solar cells was determined by single crystal X-ray diffraction for the first time. (CH3NH3)3(Bi2I9) (MBI) is a promising alternative to recently rapidly progressing hybrid organic-inorganic perovskites due to the higher tolerance against water and low toxicity. Single crystal X-ray diffraction provides detailed structural information as an essential prerequisite to gain a fundamental understanding of structure property relationships, while powder diffraction studies demonstrate a high degree of crystallinity in thin films.
Dithiine
linkage formation via a dynamic and self-correcting nucleophilic
aromatic substitution reaction enables the de novo synthesis of a
porous thianthrene-based two-dimensional covalent organic framework
(COF). For the first time, this organo-sulfur moiety is integrated
as a structural building block into a crystalline layered COF. The
structure of the new material deviates from the typical planar interlayer
π-stacking of the COF to form undulated layers caused by bending
along the C–S–C bridge, without loss of aromaticity
and crystallinity of the overall COF structure. Comprehensive experimental
and theoretical investigations of the COF and a model compound, featuring
the thianthrene moiety, suggest partial delocalization of sulfur lone
pair electrons over the aromatic backbone of the COF decreasing the
band gap and promoting redox activity. Postsynthetic sulfurization
allows for direct covalent attachment of polysulfides to the carbon
backbone of the framework to afford a molecular-designed cathode material
for lithium–sulfur (Li–S) batteries with a minimized
polysulfide shuttle. The fabricated coin cell delivers nearly 77%
of the initial capacity even after 500 charge–discharge cycles
at 500 mA/g current density. This novel sulfur linkage in COF chemistry
is an ideal structural motif for designing model materials for studying
advanced electrode materials for Li–S batteries on a molecular
level.
Porous polymers were prepared by cyclotrimerization reaction in molten p-toluenesulfonic acid. Their properties could be tailored by functionalization of the aromatic diacetyl monomers. Thus, a range of homo-and copolymers based on hydrogen-, amine-, or nitro-functionalized 4,4′-diacetylbiphenyl derivatives and 1,4-diacetylbenzene was synthesized. The pores size could be tuned from mainly microporous to hierarchical micro-and mesoporous or even hierarchical micro-and macroporous. BET surface areas up to 720 m 2 /g and total pore volumes up to 1.76 cm 3 /g were achieved. The formation of different pore types was related to the solvent−monomer/polymer interactions, which is shown by 15 N solid state MAS NMR spectroscopy and SEM. Other physical properties such as surface polarity and thermal stability were influenced by the different monomers as well.
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