Zinc-metal–organic frameworks with tunable UV diffuse-reflectance as sunscreens

A clean high-concentration chlorine dioxide bleaching process at room temperature facilitating the rapid degradation of lignin and its kinetic

Elemental Chlorine-Free (ECF) bleaching is a globally prevalent pulping technology that primarily utilizes chlorine dioxide (ClO2) as a bleaching agent. However, the chlorination side reactions during ECF bleaching lead to the formation of chlorinated adsorbable organic halides (AOX), which are difficult to degrade and pose a potential threat to the ecological environment. This study presents a novel high-concentration ClO2 pulping bleaching technology at room temperature, which effectively suppresses the chlorination side reactions through the strong oxidizing properties of high-concentration ClO2, thereby achieving both bleaching and a reduction in AOX generation. The results indicate that high concentrations of ClO2 efficiently removed residual lignin from the pulp, promoted the cleavage of lignin ether bonds, and had no adverse impact on the strength or crystalline structure of the cellulose. The amount of AOX was effectively controlled to 0.41 kg/t pulp. Kinetic analysis demonstrated that the degradation of lignin in this bleaching system follows first-order reaction kinetics, with an activation energy of 1310.78 J/mol. Approximately 95 % recovery of the ClO2 solution was achieved through a four-step reabsorption method. This technology advances the development of pulping and bleaching techniques and provides theoretical guidance for the innovation of cleaner pulping and papermaking technologies.

Endogenous Free-Electron-Involved Coreactant-Free Electrochemiluminescence from Nanoclusters and Its Immunoassay Application

All of the commercialized electrochemiluminescence (ECL) immunoassays are automatically conducted at +1.40 V (vs Ag/AgCl) in the coreactant route. To alleviate the exogenous effect of coreactants and simplify the operation procedures, herein, a sulfur-vacancy-involved and free electron strategy is proposed to exploit Au nanoclusters (NCs) as anodic electrochemiluminophores and perform a coreactant-free immunoassay. The deficient coordination between the sulfhydryl of Met and the Au core might induce the departure of partial S atoms and enable Met-capped AuNCs (Met-AuNCs) with a sulfur-vacancy-involved electron-rich nature. The electron-rich nature tends to endow Met-AuNCs with unpaired endogenous free electrons, which can directly combine exogenous holes for light emitting. Coreactant-free ECL at around +0.86 V is consequently and conveniently achieved by merely oxidizing Met-AuNCs at the anode. The coreactant-free ECL is qualified to determine human carcinoembryonic antigen from 10 to 5000 pg/mL with a limit of detection of 5 pg/mL. Electron paramagnetic resonance provides clear evidence that endogenous free electrons within Met-AuNCs play an important role in the generation of coreactant-free ECL. This sulfur-vacancy-involved and free electron strategy is promising for designing nanoelectrochemiluminophores with improved immunoassay performance.

Recent advances in photothermal nanomaterials for ophthalmic applications

The human eye, with its remarkable resolution of up to 576 million pixels, grants us the ability to perceive the world with astonishing accuracy. Despite this, over 2 billion people globally suffer from visual impairments or blindness, primarily because of the limitations of current ophthalmic treatment technologies. This underscores an urgent need for more advanced therapeutic approaches to effectively halt or even reverse the progression of eye diseases. The rapid advancement of nanotechnology offers promising pathways for the development of novel ophthalmic therapies. Notably, photothermal nanomaterials, particularly well-suited for the transparent tissues of the eye, have emerged as a potential game changer. These materials enable precise and controllable photothermal therapy by effectively manipulating the distribution of the thermal field. Moreover, they extend beyond the conventional boundaries of thermal therapy, achieving unparalleled therapeutic effects through their diverse composite structures and demonstrating enormous potential in promoting retinal drug delivery and photoacoustic imaging. This paper provides a comprehensive summary of the structure-activity relationship between the photothermal properties of these nanomaterials and their innovative therapeutic mechanisms. We review the latest research on photothermal nanomaterial-based treatments for various eye diseases. Additionally, we discuss the current challenges and future perspectives in this field, with a focus on enhancing global visual health.

Patterned durable superhydrophobic and UV protective cotton fabric prepared through inkjet printing of Zn-based MOFs and long alkyl chain siloxane

In order to solve the problems of high energy consumption, high raw material consumption and poor air permeability of fabrics in the dip-baking method, a simple low-liquid inkjet printing method was used to prepare superhydrophobic cotton fabrics. Inkjet printing technology enables precise control over the printing position and droplet amount, allowing for the creation of superhydrophobic patterns on the fabric surface. ZIF-8 precursor solution and long alkyl chain siloxane were formulated as suitable inks and printed on the surface of the fabric, forming a rough interface with low surface energy. The surface micromorphology and chemical structure of the fabric samples were characterized in detail. The prepared ZIF-HDTMS-cotton fabric exhibited superhydrophobic property with a high water contact angle of 158° and self-cleaning property against liquid and solid contaminants. Importantly, after undergoing a variety of harsh damage tests, the modified fabric still exhibited good superhydrophobicity, indicating its favorable chemical stability and mechanical durability. Compared to raw cotton fabric, the treated fabric exhibited an air permeability rate of 311.6 L/m2/s, proving its excellent breathability. Due to the high absorption capacity of ZIF-8 to ultraviolet rays, the prepared cotton fabric has obtained a certain ultraviolet protection effect. In addition, through infrared camera observation, it is found that the ZIF-HDTMS-cotton fabric also has a good anti-permeation effect on hot water, which can play a role in preventing scalding. These findings pave the way for the development of patterned multifunctional textiles through precise inkjet printing technology.

Design of Bombyx mori (B. mori) Silk Fibroin Microspheres for Developing Biosafe Sunscreen

Sunscreens play a crucial role in protecting the skin from ultraviolet (UV) damage. However, present commercial sunscreens have a tendency to generate free radicals in the UV window, resulting in serious inflammatory responses and health problems. In this study, we demonstrate that silk fibroin microspheres (SFMPs) assembled from regenerated silk fibroin (SF) could scavenge free radicals while preventing UV irradiation and thus present a promising sunscreen. The SFMP reflected more UV light than SF and presented a higher stability than that of organic commercial sunscreens. In vitro analysis proved that SFMP could more efficiently scavenge the hydroxy radical and reduce the intracellular reactive oxygen than titanium dioxide (TiO2). In vivo experiments exhibited that SFMP provided stronger skin protection against UV irradiation than commercial sunscreens and TiO2. Furthermore, SFMP treatment significantly inhibited the skin inflammatory response. This work suggests that the SFMP has great potential to be developed into a biosafe sunscreen.

Conjugated Network Supporting Highly Surface-Exposed Ru Site-Based Artificial Antioxidase for Efficiently Modulating Microenvironment and Alleviating Solar Dermatitis

Solar dermatitis, a form of acute radiation burn that affects the skin, results from overexposure to ultraviolet B (UVB) radiation in strong sunlight. Cell damage caused by the accumulation of reactive oxygen species (ROS) produced by UVB radiation plays an important role in UVB-induced inflammation in the skin. Here, for efficiently scavenging excess ROS, modulating the microenvironment, and alleviating solar dermatitis, a π-conjugated network polyphthalocyanine supporting a highly surface-exposed Ru active site-based artificial antioxidase (HSE-PPcRu) is designed and fabricated with excellent ROS-scavenging, antioxidant, and anti-inflammatory capabilities. In photodamaged human keratinocyte cells, HSE-PPcRu could modulate mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B signaling pathways, prevent DNA damage, suppress apoptosis, inhibit pro-inflammatory cytokine secretion, and alleviate cell damage. In vivo animal experiments reveal the higher antioxidant and anti-inflammatory efficacies of HSE-PPcRu by reversing the activation of p38 and c-Jun N-terminal kinase, inhibiting expression of cyclooxygenase-2, interleukin-6, interleukin-8, and tumor necrosis factor-α. This work not only provides an idea for alleviating solar dermatitis via catalytically scavenging ROS and modulating the microenvironment but also offers a strategy to design an intelligent conjugated network-based artificial antioxidase with a highly surface-exposed active site.

ZIF-8 integrated with polydopamine coating as a novel nano-platform for skin-specific drug delivery

Metal-organic frameworks (MOFs) are highly promising as a novel class of drug delivery carriers; however, there are few reports about their application in nanoparticle-based formulations for dermal administration. In this work, we developed a novel kind of nanoparticular system based on zeolitic imidazolate framework-8 (ZIF-8) and polydopamine (PDA) modification for improving the dermal delivery of 5-fluorouracil (5-FU). The structures and properties of the prepared nanoparticles were characterized using a variety of analytical methods. Their ex vivo delivery performance in the skin was investigated using Franz cells, and the underlying mechanisms were studied via confocal laser scanning microscopy (CLSM) and hematoxylin-eosin (HE) experiments which were employed to probe the penetration pathway and the interaction between nanoparticles and the skin. The results revealed that both 5-FU@ZIF-8 and ZIF-8@5-FU@PDA had an enhancement effect on the deposition of 5-FU in the skin, and the surface coating of PDA could further reduce drug permeation across the skin, especially in the case of impaired skin, in comparison with the drug solution. The CLSM study using rhodamine 6G as the fluorescent probe to mimic 5-FU indicated that ZIF-8 and ZIF-8@PDA could deliver their payloads into the skin via two pathways, i.e., intercellular and follicular ones, and the follicular route was shown to be particularly important for ZIF-8@PDA, in which the drug and carrier were co-delivered into the skin as an intact particle. This study provides evidence for using ZIF-8 and PDA modification for skin-specific drug delivery and offers an effective avenue to develop novel nanoplatforms for dermal application to treat skin diseases.