ACS Materials Letters最新文献

Medical phantoms mimic aspects of procedures like computed tomography (CT), ultrasound (US) imaging, and surgical practices. However, the materials for current commercial phantoms are expensive and the fabrication with these is complex and lacks versatility. Therefore, existing material solutions are not suitable for creating patient-specific phantoms. We present a novel and cost-effective material system (utilizing ubiquitous sodium alginate hydrogel and coconut fat) with independently and accurately tailorable CT, US, and mechanical properties. By varying the concentration of alginate, cross-linker, and coconut fat, the radiological parameters and the elastic modulus were adjusted independently in a wide range. The independence was demonstrated by creating phantoms with features hidden in US, while visible in CT imaging and vice versa. This system is particularly beneficial in resource-scarce areas since the materials are cheap (<$ 1 USD/kg) and easy to obtain, offering realistic and versatile phantoms to practice surgeries and ultimately enhance patient care.

Protein hydrogel fibers hold great promise for diverse applications. However, the challenge lies in developing rapid and straightforward methods for the one-step fabrication of high-performance protein-based hydrogel optical fibers. Here, we present a general charge-conversion-induced complexation toughening (CCICT) strategy for preparing protein hydrogel fibers in 15 s. The in situ introduction of polyelectrolyte–micelle complexes enhances the fibers’ mechanical, antiswelling, and antibacterial properties. The protein components confer biocompatibility, enzymatic degradability, and strong tissue adhesion to the hydrogel fibers. Furthermore, the as-prepared fibers demonstrate excellent optical transmission with minimal attenuation of 0.15–0.50 dB cm^–1 across various wavelengths. The hierarchical multinetwork structure imparts outstanding adaptability and stability in mechanical and optical performance. Also, the protein fibers effectively deliver light for interventional photothermal cancer therapy beneath the skin of mice. Their rapid degradation in physiological environments promotes efficient wound healing. Therefore, this developed CCICT approach and these high-performance protein fibers are anticipated to have broad applications.

The simultaneous attainment of high-photoelectric performance and stability has long been a challenge for hybrid perovskites, which are typically characterized by the low stability of three-dimensional perovskites and the poor photoelectric performance of low-dimensional perovskites. Here, we present a novel perovskite assembly strategy aimed at enhancing both the photoelectric gain and stability for X-ray detection. This strategy employs a viologen as a cation, leveraging its strong electrostatic interaction, low LUMO, and capability for photogenerated charge separation and transport to enhance stability, reduce the band gap, and unlock photogenerated carrier barriers while integrating the benefits of low-dimensional perovskites. The obtained zero-dimensional viologen perovskite exhibits exceptional comprehensive performance, including high X-ray detection performance (in vacuum), low X-ray dose rate resolution, inhibited ion migration, low dark current drift and noise current, and remarkable chemical and long-term stability (sustained in air with 50–75% relative humidity for 1 year, followed by 60 h of UV irradiation at 80 °C).

Medical phantoms mimic aspects of procedures like computed tomography (CT), ultrasound (US) imaging, and surgical practices. However, the materials for current commercial phantoms are expensive and the fabrication with these is complex and lacks versatility. Therefore, existing material solutions are not suitable for creating patient-specific phantoms. We present a novel and cost-effective material system (utilizing ubiquitous sodium alginate hydrogel and coconut fat) with independently and accurately tailorable CT, US, and mechanical properties. By varying the concentration of alginate, cross-linker, and coconut fat, the radiological parameters and the elastic modulus were adjusted independently in a wide range. The independence was demonstrated by creating phantoms with features hidden in US, while visible in CT imaging and vice versa. This system is particularly beneficial in resource-scarce areas since the materials are cheap (<$ 1 USD/kg) and easy to obtain, offering realistic and versatile phantoms to practice surgeries and ultimately enhance patient care.

Intracellular calcium ion (Ca²⁺) homeostasis is closely associated with the maintenance of cellular functions and even influences the process of cellular fate. Particularly, Ca²⁺ homeostasis directly or indirectly participates in various methods of tumor occurrence and development, including proliferation, migration, and apoptosis of tumor cells. Considering the advancements in strategies for cancer therapy based on disrupting Ca²⁺ homeostasis, this article provides a comprehensive review from the perspective of the relationship between Ca²⁺ homeostasis and tumor therapy, focusing on the common Ca²⁺-based nanomaterials and self-regulatory mechanisms of Ca²⁺ homeostasis toward diagnostic and therapeutic applications. Notably, the disruption of Ca²⁺ homeostasis provides exceptional possibilities for the design of Ca²⁺-based nanomaterials through various pathways, such as inducing Ca²⁺ overload to directly kill tumor cells, indirectly inhibiting tumor growth by affecting various tumor microenvironments, and promoting calcification phenomena for bioimaging in tumor diagnosis. Finally, we summarize the article with a perspective, exploring limitations and challenges in applying Ca²⁺-based materials mediated by disrupting Ca²⁺ homeostasis and providing prospects for their clinical development.

All-inorganic perovskite CsPbBr₃ single crystals are considered a next-generation X-ray detector owing to their excellent photoelectric properties. However, strong ion migration hinders the application of CsPbBr₃ detectors, especially those irradiated under high-flux hard X-rays. Herein, we prepared Cs_1–mRb_mPbBr₃ single crystals by partially replacing Cs atoms with Rb atoms to intensify the lattice distortion and suppress ion migration in CsPbBr₃. A Cs_0.7Rb_0.3PbBr₃ single-crystal detector operating at 120 kV_p X-rays with a flux of up to 10⁶ photons s^–1 mm^–2 was produced. This Cs_0.7Rb_0.3PbBr₃ detector shows a dark current density as low as 1.01 μA cm^–2, a high sensitivity of 33631 μC Gy^1– cm^–2, and a low detection limit of 148 nGy s^–1 under 120 kV_p X-rays. Furthermore, the Cs_0.7Rb_0.3PbBr₃ detector exhibits a stable X-ray detection capability for over 30 days under ambient conditions, indicating its potential for wide-scale application in high-flux hard X-ray detection.

Progress in techniques for manipulating chemisorption has substantially advanced various applications. Herein, we present a widely applicable method to manipulate chemisorption by adjusting the carrier concentration of the adsorbent. We demonstrate that in both n- and p-type adsorbents, an increase in the electron concentration of the adsorbent enhances the chemisorption of oxidizing adsorbates. In contrast, a decrease in electron concentration promotes the chemisorption of reducing adsorbates. These findings are verified using first-principles calculations based on density functional theory. We demonstrate that the adsorption energy of the adsorbate and the energy difference between the adsorbate states and the Fermi energy can be manipulated by the proposed method. The manipulation method yields different effects for each adsorbate. Therefore, the degree of manipulation can be utilized as a unique fingerprint for adsorbate identification. The proposed method allows for repeatable manipulations and is compatible with existing techniques.

Low-coordinated sites can effectively activate adsorbants and promote electrochemical reactions with slow kinetics and multielectron transfer processes, but achieving high exposure rates of low-coordinated sites on the electrocatalyst surface remains challenging. Herein, we first present the synthesis of the porous Pd₃Pb metallene aerogels (MAs) with low-coordinated Pd–Pb sites through dynamic reconfiguration strategy for alcohol oxidation reaction (AOR). The porous Pd₃Pb MAs possess high mass activity (1.63 A mg_Pd^–1), specific activity (6.28 mA cm^–2), and antipoisoning property in ethylene glycol oxidation reaction (EGOR), superior to other prepared catalysts. The same trend was observed in the ethanol oxidation reaction and glycerol oxidation reaction. Mechanism studies show that porous Pd₃Pb MAs with low-coordinated Pd–Pb sites could provide more unsaturated sites for adsorption and activation of ethylene glycol, as well as lowering the reaction energy barriers of CH₂OHCHO*, CH₂OHCOO*, and COOCOO*. This work explored a novel idea for the design Pd-based catalysts in antipoisoned AOR.

Wound infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have attracted wide attention owing to acidic biofilms and the alkaline wound microenvironment, which result in hindering wound healing. In this work, we prepared an acid–base responsive bionic claw microneedle (MN) loaded with Au@ZnO/Ag (AZA) core–shell nanoparticles, which shows excellent photothermal transition and antibacterial activity. In the acidic medium of the biofilm, 97.98% of bacteria were successfully eradicated under mild thermal conditions (≤40 °C). In the alkaline wound microenvironment, inflammatory cytokines were inhibited by Ag⁺. Vascular endothelial growth factor expression was promoted by trace Zn²⁺, and the wound healing rate increased by up to 24.02% compared to the control group. The bionic claw MN loaded with AZA effectively combines the benefits of low-temperature acidic sterilization and alkaline anti-inflammatory activity. The promotion of MRSA infected wound healing through the synergistic effect of released Zn²⁺/Ag⁺ and the mild thermal impact showcases new avenues for clinical treatment.

Biobased materials with superior porosity are the preferred choice for high-performance and environmentally friendly gas sensors. Here, a pore-refined colorimetric aerogel with significant-improved porous structure and mechanical integrity is developed through the strategic incorporation of hydrophilic poly(vinyl alcohol) (PVA) in nanocellulose, evidenced by a 14.35-fold increase in surface area, a 21.24-fold improvement in pore volume, and a 16.91-fold rise in gas adsorption–desorption capacity, along with advancements in both static (5.20-fold) and dynamic (5.59-fold) compressive strengths. The enhancement in performance is attributed to the addition of PVA, which promotes uniformity in the gel network and forms hydrogen bonds with cellulose, thereby minimizing structural changes during drying and refining of the pore structure. The aerogels demonstrate sensitive, gradient, recognizable, and highly reversible color changes to ammonia stimuli (down to 10 ppm). Intelligent tags based on the enhanced aerogels demonstrate earlier identification of spoilage in monitoring different types of meat, proving their potential in smart packaging.