Healable antifouling films are fabricated by the exponential layer-by-layer assembly of PEGylated branched poly(ethylenimine) and hyaluronic acid followed by post-crosslinking. The antifouling function originates from the grafted PEG and the extremely soft nature of the films. The rapid and multiple healing of damaged antifouling functions caused by cuts and scratches can be readily achieved by immersing the films in normal saline solution.
Lead halide perovskite solar cells have recently emerged as a very promising photovoltaic technology due to their excellent power conversion efficiencies; however, the toxicity of lead and the poor stability of perovskite materials remain two main challenges that need to be addressed. Here, for the first time, we report a lead-free, highly stable CHNHCuBrI compound. The CHNHCuBrI films exhibit extraordinary hydrophobic behavior with a contact angle of ∼90°, and their X-ray diffraction patterns remain unchanged even after 4 h of water immersion. UV/vis absorption spectrum shows that CHNHCuBrI compound has an excellent optical absorption over the entire visible spectrum. We applied this copper-based light absorber in printable mesoscopic solar cell for the initial trial and achieved a power conversion efficiency of ∼0.5%. Our study represents an alternative pathway to develop low-toxic and highly stable organic-inorganic hybrid materials for photovoltaic application.
Very thin polydopamine (PDA) coating with 20–30 nanometer thickness is prepared through self‐polymerization of dopamine. This PDA nanocoating can generate high local heat upon near‐infrared (NIR) irradiation in minutes, leading to the efficient killing of both Gram negative and positive bacteria, and fungus as well.
The
toxicity and the instability of lead-based perovskites might eventually
hamper the commercialization of perovskite solar cells. Here, we present
the optoelectronic properties and stability of a two-dimensional layered
(C6H5CH2NH3)2CuBr4 perovskite. This material has a low E
g of 1.81 eV and high absorption coefficient
of ∼1 × 105 cm–1 at the most
intensive absorption at 539 nm, implying that it is suitable for light-harvesting
in thin film solar cells, especially in tandem solar cells. Furthermore,
X-ray diffraction (XRD), ultraviolet–visible (UV–vis)
absorption spectra, and thermogravimetric analysis (TGA) confirm the
high stability toward humidity, heat, and ultraviolet light. Initial
studies produce a mesoscopic solar cell with a power conversion efficiency
of 0.2%. Our work may offer some useful inspiration for the further
investigation of environment-friendly and stable organic–inorganic
perovskite photovoltaic materials.
Endothelial cells (ECs) play a crucial role in regulating various physiological and pathological processes. The behavior of ECs is modulated by physical (e.g., substrate stiffness) and biochemical cues (e.g., growth factors). However, the synergistic influence of these cues on EC behavior has rarely been investigated. In this study, we constructed poly(l-lysine)/hyaluronan (PLL/HA) multilayer films with different stiffness and exposed ECs to these substrates with and without hepatocyte growth factor (HGF)-supplemented culture medium. We demonstrated that EC adhesion, migration, and proliferation were positively correlated with substrate stiffness and that these behaviors were further promoted by HGF. Interestingly, ECs on the lower stiffness substrates showed stronger responses to HGF in terms of migration and proliferation, suggesting that HGF can profoundly influence stiffness-dependent EC behavior correlated with EC growth. After the formation of an EC monolayer, EC behaviors correlated with endothelial function were evaluated by characterizing monolayer integrity, nitric oxide production, and gene expression of endothelial nitric oxide synthase. For the first time, we demonstrated that endothelial function displayed a negative correlation with substrate stiffness. Although HGF improved endothelial function, HGF was not able to change the stiffness-dependent manner of endothelial functions. Taken together, this study provides insights into the synergetic influence of physical and biochemical cues on EC behavior and offers great potential in the development of optimized biomaterials for EC-based regenerative medicine.
Bacterial infections
caused by antibiotic-resistant pathogens have
become intractable problems to public health. Therefore, there is
an imperious demand for developing new approaches to effectively kill
antibiotic-resistant bacteria. In this work, we report a kind of bacteria-targeted
polydopamine nanoparticle exhibiting great photothermal killing ability
toward methicillin-resistant Staphylococcus aureus (MRSA) by nano-localized hyperpyrexia under low-power near-infrared
(NIR) light irradiation. These bacteria-targeted nanoparticles (PDA-PEG-Van)
are prepared by modifying polydopamine nanoparticles with thiol-poly(ethylene
glycol) (mPEG-SH) and vancomycin (Van) molecules. The PEG shell endows
the nanoparticles with excellent long-term circulation stability.
Due to the multivalent hydrogen-bond interactions between vancomycin and the MRSA cell
wall, the vancomycin-modified polydopamine nanoparticles can specifically
target MRSA rather than mammalian cells. These bacteria-targeted nanoparticles
are employed as a nano-localized heat source to kill MRSA via disrupting
the bacterial cell wall and membrane under irradiation of low-power
NIR light. More importantly, the surrounding healthy tissues suffer
bare damage, owing to the absence of any targeting effect of PDA-PEG-Van
toward mammalian cells and the low power of NIR light used in the
therapeutic process. Given the above advantages, the bacteria-targeted
polydopamine nanoparticles proposed in this work show tremendous potential
to treat MRSA infections, because they can effectively limit localized
heating in the infection sites to kill bacteria and cut down damage
to healthy tissues.
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