ACS Materials Letters

NIR-II Dye-Based Multifunctional Telechelic Glycopolymers for NIR-IIa Fluorescence Imaging-Guided Stimuli-Responsive Chemo-Photothermal Combination Therapy

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.

Visible Metamaterial Using a Lithium Niobate Nanoring Structure for Stretchable Color Sensing Application

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.

Extraordinarily Persistent Zero Linear Compressibility in Metal-Organic Framework MIL-122(In)

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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Dual-Ligand Surface Passivation Enables Monodisperse Ag2S Colloidal Quantum Dots for Efficient Near-Infrared Photothermal Therapy

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).