Over the last two decades, click chemistry and bioorthogonal chemistry have revolutionized the field of biomedical engineering. Extensive investigations have been conducted and allowed for unforeseeable developments in many different fields, including imaging, drug delivery, 3D cell culture, and bioprinting. The properties of advanced click and bioorthogonal chemical tools have now exceeded the expectations set by the researchers who first introduced the two concepts, calling for reevaluation. More importantly, their developments in distinct research contexts have led to conceptual divergences, which can now be a source of misunderstandings and disagreements. This perspective article aims to take a fresh look at the two concepts, with particular attention to their combination for applications in biological environments. After a short historical introduction, the definitions of click chemistry and bioorthogonal chemistry are revised, and the concept of ideal click chemistry is introduced. Chemical reactions that are commonly considered as click and bioorthogonal reactions are discussed in light of this new perspective. Finally, current challenges and new chemical concepts are presented, offering a new framework for future research.
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2D–3D tin perovskites are considered as promising candidates for realizing efficient lead-free perovskite solar cells (PSCs). However, the ultrathin 2D phases could unfavorably affect charge transport and device performance. In the present work, we demonstrate that the introduction of D-homoserine lactone hydrochloride (D-HLH) can tailor the low-dimensional phases and improve the quality of 2D–3D tin perovskite films. The functional group in D-HLH can interact with FA+ and I– as well as Sn2+ in the precursor solution. These interactions not only affect the formation of tin perovskite film and favor the formation of thicker 2D phases but also decrease the defect density and suppress the nonradiative recombination. As a result, the efficiency of tin PSCs is significantly improved from 7.97 to 12.45%, and the stability of the device is also enhanced. This work provides a feasible strategy to regulate the low-dimensional phases in 2D–3D tin PSCs toward realizing high efficiency.
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Semiconducting polymers have transport properties that can be tuned by both the synthetic design and processing techniques. Their thermopower, electronic conductivity, and low lattice thermal conductivity make them attractive in thermal management and thermoelectric applications, especially in form factors unfit for comparable inorganic ceramics. The effects of blending differing molecular weights and regioregularities of poly(3-hexylthiophene) (P3HT) on the thermal conductivity of films of P3HT doped with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane were investigated in order to develop design rules for the co-optimization of thermal and electronic properties. The thermal conductivity of blended P3HT films at room temperature was found to be controlled by the distribution of molecular weights and regioregularities of chains. The resulting thermal conductivity of P3HT at room temperature was found to span 0.2–0.85 W/mK without specialized processing methods. Upon electrical doping, a significant decrease in thermal conductivity was found at all blending compositions despite each composition having a comparable electronic conductivity. These results suggest the blending of molecular weights and regioregularities as a rational means to optimize thermal conductivity while maintaining desired electronic properties in semiconducting polymers.
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Optical imaging-guided chemo-photothermal combination therapy of cancers has attracted considerable attention, because of its capacity for personalized, precision treatment and its synergistic chemo-photothermal therapeutic effect. However, it still encounters many barriers, including an unsatisfactory diagnostic accuracy, poor physiological stability, low drug loading, and uncontrolled drug release. Here, we developed a NIR-II dye-based multifunctional telechelic glycopolymer (TTQ-TC-PFru) as a drug carrier and constructed stimuli-responsive PFru-BTZ-PBOB nanoparticles (NPs) to achieve the near-infrared IIa (NIR-IIa, 1300-1400 nm) fluorescence imaging (FI)-guided chemo-photothermal combination therapy of cancers. This multifunctional glycopolymer not only serves as the contrast agent for NIR-IIa FI but also functions as the photothermal agent for photothermal therapy (PTT). Meanwhile, the fructose polymer on TTQ-TC-PFru forms a stable boronic acid-catechol conjugate with the dipeptidyl boronic acid proteasome inhibitor bortezomib (BTZ) to achieve high drug loading (31%), satisfactory physiological stability, and controlled drug release in the acidic tumor microenvironment. In addition, one BOB-containing copolymer POEGMA-co-PBOB was introduced to further improve the stability of the system. In living tumor-bearing mice, the successfully constructed stimuli-responsive NPs PFru-BTZ-PBOB induced significant tumor regression through NIR-IIa FI-guided chemo-photothermal combination therapy. Our study thus describes the great potential of NIR-IIa FI-guided chemo-photothermal combination therapy of cancers.
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All-dielectric metamaterials present the capability to generate high quality structure colors with outstanding color purity and filtering efficiency. In this study, a visible metamaterial composed of a lithium niobate (LiNbO3) nanoring (LNR) structure on polydimethylsiloxane (PDMS) substrate is proposed. By carefully optimizing geometry configurations, a strong magnetic dipole (MD) resonance is stimulated and other multipole resonances are effectively suppressed with the assistance of surface lattice resonance, and then single reflection peaks are generated with high efficiencies up to 99% and narrow bandwidths smaller than 9 nm. Moreover, benefiting from the stretchable property of the PDMS substrate, LNR metamaterial has the potential to be actively tuned by mechanically changing the period of unit cells and then realizing the reflected color changes. Meanwhile, LNR metamaterial is also sensitive to the change of the ambient environment; the figure of merit can be up to 311.11 RIU–1. It indicates LNR metamaterial possesses potentials in stretchable electronics, color generating, light fidelity (LiFi) filtering, and biochemical sensing applications.
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Because of its rare linear stability, material with zero linear compression (ZLC) is active in many complicated environments. But it is generally difficult to acquire a single material with ZLC behavior. Herein, we reported a rare ZLC over a huge pressure range (1 atm to 10.5 GPa) in MIL-122(In) material along its a-axis direction. High-pressure angle-dispersive X-ray powder diffraction experiments revealed its structure changes under increasing hydrostatic pressure. Density functional theory calculations confirmed that the ZLC in MIL-122(In) resulted from the unconventional mechanical response of the rhombohedral wine-rack frameworks. Our work provided a new instance of the ZLC material in a large pressure range and demonstrated that the naturally soft materials, metal-organic frameworks, can also exhibit persistent pressure resistance.
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Silver sulfide (Ag2S) colloidal quantum dots (CQDs) have attracted attention as promising infrared materials owing to their broad bandgap tunability and nontoxic composition. However, synthesizing highly monodisperse Ag2S CQDs has been challenging, because they readily fuse with each other. Here, we introduce a dual-ligand passivation approach for the synthesis of highly monodisperse Ag2S CQDs. Leveraging both oleic acid and oleylamine as coligands for surface passivation, we achieve enhanced confinement of CQD morphology and effectively prevent CQD fusion. This contrasts with conventional Ag2S CQDs prepared by using solely oleylamine ligands, which show a wide size distribution due to inter-CQD fusion. This enables the exhibition of an efficient photothermal conversion capability upon illumination with an 808 nm laser, causing a rapid increase of temperature from 25 to 70 °C within 3 min. We demonstrate that incubation with 500 nM CQDs results in nearly 100% death of MCF-7 cells (human breast cancer cells) after just 5 min of 808 nm laser irradiation (1.5 W/cm2).
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