For breast cancer patients who have undergone breast‐conserving surgery, effective treatments to prevent local recurrences and metastases is very essential. Here, a local injectable therapeutic platform based on a thermosensitive PLEL hydrogel with near‐infrared (NIR)‐stimulated drug release is developed to achieve synergistic photothermal immunotherapy for prevention of breast cancer postoperative relapse. Self‐assembled multifunctional nanoparticles (RIC NPs) are composed of three therapeutic components including indocyanine green, a photothermal agent; resiquimod (R848), a TLR‐7/8 agonist; and CPG ODNs, a TLR‐9 agonist. RIC NPs are physically incorporated into the thermosensitive PLEL hydrogel. The RIC NPs encapsulated PLEL hydrogel (RIC NPs@PLEL) is then locally injected into the tumor resection cavity for local photothermal therapy to ablate residue tumor tissues and produce tumor‐associated antigens. At the same time, NIR also triggers the release of immune components CPG ODNs and R848 from thermoresponsive hydrogels PLEL. The released immune components, together with tumor‐associated antigens, work as an in situ cancer vaccine for postsurgical immunotherapy by inducing effective and sustained antitumor immune effect. Overall, this work suggests that photothermal immunotherapy based on local hydrogel delivery system has great potential as a promising tool for the postsurgical management of breast cancer to prevent recurrences and metastases.
The total synthesis of the tunicate metabolite mandelalide A and the correction of its originally assigned stereochemistry are reported. Key features of the convergent, fully stereocontrolled route include the use of a Prins cyclization for the diastereoselective construction of the tetrahydropyran subunit, Rychnovsky-Bartlett cyclization for the preparation of the tetrahydrofuran moiety, Suzuki coupling, Horner-Wadsworth-Emmons macrocyclization, and glycosylation to append the L-rhamnose-derived pyranoside.
A carbene-catalyzed
reductive coupling reaction of carboxylic esters
and substituted Hantzsch esters is disclosed. Key steps of this reaction
include one-electron reduction of a carbene catalyst-bound acyl azolium
intermediate to generate the corresponding radical intermediate for
subsequent alkylation reactions. The reaction is promoted by irradiation
with visible light without the involvement of transition-metal photocatalysts.
Mechanistic studies suggest that direct photoexcitation of the in
situ formed acyl azolium intermediate is likely responsible for this
light-induced one-electron-reduction process. Photoexcitation converts
the acyl azolium intermediate to a single-electron oxidant, enabling
single-electron oxidation of Hantzsch esters to generate radical intermediates.
Our reactions work well for a broad range of aryl carboxylic ester
and Hantzsch ester substrates. Sophisticated structures, including
those present in medicines, can be incorporated into ketone molecules
using our approach via very mild conditions that tolerate various
functional groups.
The safety issues and immunological effects of nanosized materials have drawn considerable attention. Gold nanorods (Au NRs) have promising applications in biomedical diagnosis and therapy, but their biosafety and the mechanism underlying in vivo toxicity still remain to be explored. In this study, cetyltrimethylammonium bromide (CTAB) capped Au NRs and PEG modified Au NRs are both prepared, the cytotoxicity evaluation indicates that CTAB‐Au NRs of different ratios all exhibit cytotoxicity while PEG‐Au NRs show improved biocompatibility. Furthermore, it is investigated how the surface characteristics influence toxical effects of Au NRs both in vitro and in vivo. It is found that CTAB‐Au NRs can induce acute cell necrosis, which results in the leakage of damage associated molecular patterns (DAMPs) such as mitochondrial DNA (mtDNA), subsequently triggering pulmonary inflammation. It is also revealed that the inflammation caused by CTAB‐Au NRs is probably mediated by the stimulator of interferon genes (STINGs) signaling pathway. This study explores the cytotoxicity and inflammatory toxicity of CTAB‐Au NRs, and how the surface modification affects the toxicity. The molecular pathways for the induction of pulmonary inflammation in vivo are further characterized. These findings might be of importance for designing safer and better gold‐based nanomaterials in the future.
Axially chiral styrenes bearing a chiral axis between a sterically non-congested acyclic alkene and an aryl ring are difficult to prepare due to low rotational barrier of the axis. Disclosed here is an N-heterocyclic carbene (NHC) catalytic asymmetric solution to this problem. Our reaction involves ynals, sulfinic acids, and phenols as the substrates with an NHC as the catalyst. Key steps involve selective 1,4-addition of sulfinic anion to acetylenic acylazolium intermediate and sequential E-selective protonation to set up the chiral axis. Our reaction affords axially chiral styrenes bearing a chiral axis as the product with up to > 99:1 e.r., > 20:1 E/Z selectivity, and excellent yields. The sulfone and carboxylic ester moieties in our styrene products are common moieties in bioactive molecules and asymmetric catalysis.
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