The development of flexible MXene-based
multifunctional composites
is becoming a hot research area to achieve the application of conductive
MXene in wearable electric instruments. Herein, a flexible conductive
polyimide fiber (PIF)/MXene composite film with densely stacked “rebar-brick-cement”
lamellar structure is fabricated using the simple vacuum filtration
plus thermal imidization technique. A water-soluble polyimide precursor,
poly(amic acid), is applied to act as a binder and dispersant to ensure
the homogeneous dispersion of MXene and its good interfacial adhesion
with PIF after thermal imidization, resulting in excellent mechanical
robustness and high conductivity (3787.9 S/m). Owing to the reflection
on the surface, absorption through conduction loss and interfacial/dipolar
polarization loss inside the material, and the lamellar structure
that is beneficial for multiple reflection and scattering between
adjacent layers, the resultant PIF/MXene composite film exhibits a
high electromagnetic interference (EMI) shielding effectiveness of
49.9 dB in the frequency range of 8.2–12.4 GHz. More importantly,
its EMI shielding capacity can be well maintained in various harsh
environments (e.g., extreme high/low temperature, acid/salt solution,
and long-term cyclic bending), showing excellent stability and durability.
Furthermore, it also presents fast, stable, and long-term durable
Joule heating performances based on its stable and excellent conductivity,
demonstrating good thermal deicing effects under actual conditions.
Therefore, we believe that the flexible conductive PIF/MXene composite
film with excellent conductivity and harsh environment tolerance possesses
promising potential for electromagnetic wave protection and personal
thermal management.
Tumour vasculature is generally disordered because of the production of excessive angiogenic factors by tumour cells, which results in tumour progression and reduces the effectiveness of radiotherapy or chemotherapy. Transient anti-angiogenic therapies that regulate tumour vascular morphology and function and improve the efficiency of antitumour therapy are under investigation. Recombinant human endostatin (Endostar/rhES) is a vascular angiogenesis–disrupting agent that has been used to treat non-small cell lung cancer (NSCLC) in the clinical setting. In this study, we used gold nanoparticles (AuNPs) as a drug-delivery system (DDS) for targeted tumour delivery of rhES for short therapy, which resulted in transient tumour vascular normalization, reduced permeability and hypoxia, strengthened blood vessel integrity, and increased blood-flow perfusion. Moreover, combination therapy with 5-FU over this timeframe was substantially more effective than 5-FU monotherapy. In conclusion, our research demonstrates the potential use of AuNPs as a drug-delivery platform for transporting rhES into a tumour to induce transient tumour vascular normalization and enhance the antitumour efficacy of cytotoxic drugs.
Angiogenesis is a process by which vessels are formed through preexisting ones, and this plays a key role in the progression of solid tumors. However, tumor vessels are influenced by excessive pro-angiogenic factors, resulting in deformed structures that facilitate the intravasation of tumor cells into the circulation and subsequent metastasis. Moreover, abnormal tumor vessels have low blood perfusion and thereby decreased oxygen infusion into tumors. This results in a hostile microenvironment that promotes epithelial–mesenchymal transition (EMT), a process in which epithelial cells lose their polarity and gain increased motility, which is associated with metastasis and invasion. Here, we demonstrate that gold nanoparticles (AuNPs) facilitate tumor vasculature normalization, increase blood perfusion and alleviate hypoxia in melanoma tumors. Additionally, AuNPs were observed to reverse EMT in tumors, accompanied by the alleviation of lung metastasis. These AuNPs inhibited the migration of B16F10 cells and reversed EMT in B16F10 cells, indicating that AuNPs could directly regulate EMT independent of improvements in hypoxia. Taken together, our data demonstrated that AuNPs could induce tumor vasculature normalization and reverse EMT, resulting in decreased melanoma tumor metastasis.
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