No abstract

Precisely assembled DNA nanostructures are promising candidates for the delivery of biomolecule-based therapeutics. Herein, we introduce a facile strategy for the construction of a branched DNA-based nanoplatform for codelivery of gene editing (sgRNA/Cas9, targeting DNA in the nucleus) and gene silencing (antisense, targeting mRNA in the cytoplasm) components for synergistic tumor therapy in vitro and in vivo. In our design, the branched DNA structure can efficiently load a sgRNA/Cas9/antisense complex targeting a tumor-associated gene, PLK1, through DNA self-assembly. With the incorporation of an active targeting aptamer and an endosomal escape peptide by host–guest interaction, the biocompatible DNA nanoplatform demonstrates efficient inhibition of tumor growth without apparent systemic toxicity. This multifunctional DNA nanocarrier provides a new strategy for the development of gene therapeutics.

The exploration of biocompatible materials with circularly polarized luminescence (CPL) activity is becoming an attractive topic due to the great potential application in biosensing and bioimaging. Here, we describe a strategy to fabricate new CPL-active biomaterials using achiral carbazole-based biscyanine fluorophores coassembled with chiral deoxyribonucleic acid (DNA) molecules. This cyanine molecule has been shown to behave as a DNA detecting probe, featuring strong fluorescent emission induced by restriction of intramolecular rotation (RIR). When the achiral cyanine molecules are bound to the minor groove of DNA via electrostatic attraction in aqueous solution, the chirality of the DNA molecules can be transferred to the confined RIR cyanine dyes, triggering a remarkable circularly polarized luminescent emission. The chirality of the CPL signal can be regulated by the structures of the DNA templates. Stimuli-responsive CPL activates were observed from DNA–cyanine complexes. We further verified this strategy on different DNA-based nanomaterials, including DNA origami nanostructure. Our design presents a new avenue to fabricate compatible CPL materials.

The power conversion efficiency (PCE) of low-bandgap mixed Pb−Sn perovskite solar cells (PSCs) has been significantly hindered by large open-circuit voltage (V oc ) loss and poor fill factor (FF). Herein, mixed Pb−Sn perovskite films with a composition (FASnI 3 ) 0.6 (MAPbI 3 ) 0.4 were processed with a simple delayed annealing (DA) treatment that enables perovskite films with significantly reduced surface roughness. The treatment reduces nonradiative recombination of interfacial contacts when t h e p e r o v s k i t e fi l m s a r e i n t e r f a c e d w i t h p o l y ( 3 , 4ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) and fullerene (C 60 ). Charge transfer at the carrier-collection interfaces has been effectively improved, in agreement with time-resolved photoluminescence (TRPL) and transient photovoltage/photocurrent results. Consequently, the champion cell based on perovskite films with DA treatment shows a high V oc of 0.824 V, indicating a greatly suppressed V oc loss (for a bandgap of ∼1.25 eV), and an overall PCE of over 18.6%.

Conventional energy-integration black-white X-ray imaging lacks spectral information of X-ray photons. Although X-ray spectra (energy) can be distinguished by photon-counting technique typically with CdZnTe detectors, it is very challenging to be applied to large-area flat-panel X-ray imaging (FPXI). Herein, we design multi-layer stacked scintillators of different X-ray absorption capabilities and scintillation spectrums, in this scenario, the X-ray energy can be discriminated by detecting the emission spectra of each scintillator, therefore the multispectral X-ray imaging can be easily obtained by color or multispectral visible-light camera in one single shot of Xray. To verify this idea, stacked multilayer scintillators based on several emerging metal halides were fabricated in the cost-effective and scalable solution process, and proofof-concept multi-energy FPXI were experimentally demonstrated. The dual-energy Xray image of a "bone-muscle" model clearly showed the details that were invisible in conventional energy-integration FPXI. By stacking four layers of specifically designed multilayer scintillators with appropriate thicknesses, a prototype FPXI with four energy channels was realized, proving its extendibility to multispectral or even hyperspectral X-ray imaging. This study provides a facile and effective strategy to realize energyresolved flat-panel X-ray imaging.