We have developed a novel lipase-mediated method to realize the Dakin reaction. A wide range of hydroxylated benzaldehydes could be oxidized with high yields (from 90% to 97%) under mild reaction ...conditions. Moreover, this lipase-mediated reaction could be scaled up easily and Novozym 435 could be reused more than 10 runs without an obvious decrease in enzyme activity. This protocol expands the application of lipase in organic synthesis and offers a complementary route for the Dakin reaction.
In the work, mucor miehei lipase (MML) was covalently immobilized on the 2,4,6-trichloro-1,3,5-triazine (TCT)-modified magnetite nanoparticles. Then, the immobilized MML was utilized in the synthesis ...of functionalized 4H-Chromenes via a multicomponent reaction firstly. Under the optimized reaction conditions, immobilized MML displayed high catalytic performance (Yield: 81-96%) and excellent reusability, indicating a high potential for practical operation.
The construction of multicomponent hybrid nanomaterials with well-controlled architecture, especially bearing an ordered homogeneity and distribution of the subunits with tunable functions, is a key ...challenge in chemistry and material science. Herein, we reported a versatile and novel strategy to fabricate core–satellite multicomponent nanostructures with tunable interparticle distances and catalysis properties by the combination of surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization and self-assembly. The arrangement and interparticle distance of gold satellites could be precisely tuned by the SI-RAFT polymerization process and the feeding ratio of gold nanoparticles (AuNPs) and the core nanoparticle. It is worth to note that multilayered core–satellite nanostructures have been fabricated by a high-feeding ratio of AuNPs and magnetite NP (MNP)@SiO2–PNIPAm. Notably, the core–satellite MNP@SiO2–PNIPAm–Au nanoparticles exhibited excellent thermoresponsive behaviors with the change of temperature. Furthermore, the catalytic efficiency of MNP@SiO2–PNIPAm–Au nanoparticles via the reduction of 4-nitrophenol to 4-aminophenol can be well modulated by the nanoparticle size, temperature, and polymer feed ratio. This strategy for precise construction of core–satellite nanostructures would open a new pathway to construct multicomponent functional nanostructures.
Bacterial infections accompanied with wound healing often lead to more serious health hazards to patients. Therefore, it is urgent to explore a wound dressing that can promote wound repair while ...possessing antibacterial capability. Here, we constructed a multifunctional hydrogel dressing by a redox-initiated cross-linking reaction of methacrylated hyaluronic acid (HAMA), 5,10,15,20-tetra (4-methacrylate phenyl) porphyrin (TPP), and dopamine methacrylamide (DMA), named HAMA-TPP-DMA, with broad-spectrum photodynamic antibacterial capability, where the aggregation of TPP photosensitizer units could be greatly inhibited to produce more singlet oxygen. The hydrogel has excellent biodegradability and biocompatibility, providing favorable conditions for wound healing. Furthermore, the incorporation of dopamine into the hydrogel gives the wound dressing with enhanced adhesiveness, benefiting for the wound repair. More importantly, the antibacterial experiments in vitro and mice wound models in vivo showed that the HAMA-TPP-DMA hydrogel can significantly resist bacteria and accelerate the wound healing in mice (the closure rate > 98% after 15 days). Thus, this hydrogel dressing with superior antibacterial infection and wound healing capability provides a promising strategy in wound repair.
The aggregation-caused quenching (ACQ) effect of photosensitizers and multidrug resistance are the major obstacles in photodynamic therapy (PDT) and chemotherapy, respectively. Synergistic ...photo-chemotherapy is a promising cancer treatment to overcome the short boards of each single therapy. However, the fabrication of nanocarriers acting as both photosensitizers in PDT and the vehicle of drug release is a key challenge. Herein, we constructed a well-defined porphyrin-containing Janus macromolecular brush and used it as both a photosensitizer and a pH-responsive vehicle for DOX release. The Janus macromolecular brush with pH-responsive side chains and porphyrin units linked covalently in each repeat unit was synthesized by the combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and click chemistry. The high grafting content of porphyrin units in the macromolecular brush improved the DOX loading capability by π–π stacking and therefore reduced the total treatment dose of DOX-loaded macromolecular brush nanoparticles (NPs). The pH-responsive side chains played triple roles in synergistic cascade-amplified PDT and enhanced chemotherapy including an executor of controlled drug release, a ligand with a mitochondria-targeting feature, and a barrier to reduce the ACQ effect of porphyrin units. In vitro and in vivo studies confirmed that the DOX-loaded macromolecular brush NPs exhibited high phototoxicity and significant tumor inhibition efficacy.
Synergistic photodynamic therapy (PDT) and chemotherapy has emerged as a promising cancer treatment to overcome the challenges of a single modality. Herein, we constructed new pH-responsive vesicles using porphyrin-containing Janus macromolecular brushes as theranostic nanocarriers to encapsulate high-loading doxorubicin (DOX) for synergistic cascade-amplified PDT and enhanced chemotherapy. The high grafting content of porphyrin units in Janus macromolecular brushes improved DOX loading capability by π–π stacking for enhanced chemotherapy. Moreover, pH-responsive side chains subsequently enhanced the suppression of the aggregation-caused quenching (ACQ) effect of porphyrins for cascade-amplified PDT. In vitro and in vivo studies confirmed that DOX-loaded macromolecular brush nanoparticles exhibited high phototoxicity and significant tumor inhibition efficacy.
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Premature and incomplete drug release is the typical bottleneck of drug release in traditional chemotherapy. Synergistic therapies are highly desirable in medicine and biology because they can ...compensate for the drawbacks of single therapy and significantly enhance the therapeutic efficacy. Herein, a novel near infrared (NIR)-activated polymeric nanoplatform with upper critical solution temperature (UCST) was constructed for image-guided synergistic photothermal therapy (PTT) and chemotherapy. UCST-responsive amphiphilic block copolymers were synthesized by reversible addition–fragmentation chain-transfer (RAFT) polymerization and then co-assembled with IR780 and cabazitaxel (Cab) to form spherical nanoparticles (NPs). IR780/Cab dual-loaded UCST polymeric NPs can produce local heating upon NIR laser irradiation and further lead to the dissociation of cargo-loaded NPs and controlled release of Cab. IR780 plays the role of both a heating generator and an activator for “on-demand” drug release. The investigation of in vivo fluorescence and photothermal imaging clearly demonstrated tumor targeting. Notably, both in vitro and in vivo studies illustrated that the synergistic PTT and chemotherapy presented better anticancer efficacy than that of PTT and chemotherapy simplely combined. Thus, the well-defined polymeric nanoplatform opens a versatile and effective path to develop image-guided synergistic therapies for tumor treatment.
Photodynamic therapy (PDT) has attracted considerable attention, since it could effectively kill bacteria and prevent the development of multi-drug resistance. However, PDT currently suffers from ...oxygen limitation and hypoxia is a prominent feature of pathological states encountered in inflammation, wounds, and bacterial infections. Herein, an oxygen-tunable nanoplatform based on perfluorocarbon-conjugated tetrafluorophenyl bacteriochlorin (FBC-F) was designed for effective antimicrobial therapy. The introduction of fluorine atoms can not only increase the reactive oxygen species (ROS) production capacity of FBC-F by facilitating the intersystem crossing (ISC) process of FBC photosensitizers, but also make FBC-F deliver more oxygen into the treatment sites benefiting from the outstanding oxygen-dissolving capability of perfluorocarbon. As a consequence, the FBC-F nanoplatform was able to efficiently generate singlet oxygens for type II PDT, as well as superoxide anions and hydroxyl radicals for type I PDT, and significantly improve antibacterial efficacy in vitro. In vivo experiments further proved that the FBC-F with a powerful antibacterial capability could well promote wound healing and destroy biofilm. Thus, this FBC-F nanoplatform may open a new path in photodynamic antibacterial therapy.
Photodynamic therapy is a promising antibacterial treatment, but its efficacy is severely compromised by hypoxia. To overcome such a limitation, we constructed an oxygen-regulated nanoplatform (FBC-F) by attaching perfluorocarbons (PFC) to the NIR photosensitizer (FBC). As an analogue of bacteriochlorin, FBC could generate 1O2 through energy transfer , as well as O2−· and ·OH through electron transfer for synergistic type I and type II photodynamic antibacterial therapy. Benefiting from the oxygen-dissolving capability of PFC, FBC-F could efficiently deliver more oxygen into the treatment site and alleviate the hypoxic environment. As a consequence, FBC-F could effectively generate large amounts of reactive oxygen species to achieve improved antibacterial efficacy and provide a promising approach for eliminating biofilms.
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A mitochondria-targeting supramolecular photosensitizer system TPP-QAS/WP5/DTAB was constructed based on a host-guest inclusion complex. The supramolecular system could efficiently release and ...activate TPP-QASs in an acidic environment, which have been demonstrated to preferentially accumulate in mitochondria. Singlet oxygen (
O
) could be in situ generated in mitochondria under light irradiation, further enhancing the PDT efficacy.
Photodynamic therapy (PDT) is a promising treatment modality for cancer treatment owing to its minimally invasive nature and negligible drug resistance. However, the disadvantages of conventional ...photosensitizers including universal aggregation-caused quenching (ACQ) effect or nonselective activation are still major hurdles for PDT clinical application. Herein, a new strategy for flexible manipulating photosensitizers in effective quenching and quick recovery of photoactivation is presented by introducing porphyrin units into upper critical solution temperature (UCST) block copolymer decorated gold nanorods (AuNR-P(AAm-co-AN-co-TPP)-b-PEG). The UCST block copolymer can achieve a self-quenching effect to make the porphyrin photosensitizers in the “Off” state by π–π stacking and hydrogen bonding interactions at physiological temperature, which greatly minimizes the nonselective phototoxicity of the photosensitizers to meet the requirement of phototherapy protected from sunlight. After the immigration of AuNR-P(AAm-co-AN-co-TPP)-b-PEG nanoparticles into the tumor tissue and the internalization by cancer cells, the UCST polymer chains can be extended under the local heating of AuNRs by NIR light irradiation, and then porphyrin photosensitizers are turned “On” to dramatically boost the PDT efficiency. Therefore, the process of PDT could be well manipulated in the “Off/On” state by the hybrid nanoplatform with UCST block copolymers and AuNRs, which will open new horizons for clinical treatments of PDT.
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