Siloxane Hybrid Material-Encapsulated Highly Robust Flexible μLEDs for Biocompatible Lighting Applications

NIR Light-Triggered Structural Modulation of Self-Assembled Prion Protein Aggregates

The self-replication of misfolded prion protein (PrP) aggregates is the major pathological event of different prion diseases, affecting mammal brains by cross-species transmission. Here, the structural modulation of PrP aggregates are reported by activated carbon materials upon near-infrared (NIR) light irradiation. Activated carbon cobalt (ACC) nanosheets are synthesized using glycerol and metal salts to utilize the charge carriers released under NIR light exposure. According to the microscopy and spectroscopy analysis results, NIR light-excited ACC nanosheets successfully dissociate the β-sheet-rich and plaque-like PrP aggregates into denatured fragments by modifying their amino acid residues. The in vitro assay results demonstrate that ACC nanosheets possess biocompatibility to neuroblastoma cells and alleviating effect against the neurotoxicity of PrP aggregates. This work suggests the first potential photodynamic platform for the future treatment of prion diseases.

Direct Optical Patterning of Quantum Dots: One Strategy, Different Chemical Processes

Patterning, stability, and dispersion of the semiconductor quantum dots (scQDs) are three issues strictly interconnected for successful device manufacturing. Recently, several authors adopted direct optical patterning (DOP) as a step forward in photolithography to position the scQDs in a selected area. However, the chemistry behind the stability, dispersion, and patterning has to be carefully integrated to obtain a functional commercial device. This review describes different chemical strategies suitable to stabilize the scQDs both at a single level and as an ensemble. Special attention is paid to those strategies compatible with direct optical patterning (DOP). With the same purpose, the scQDs' dispersion in a matrix was described in terms of the scQD surface ligands' interactions with the matrix itself. The chemical processes behind the DOP are illustrated and discussed for five different approaches, all together considering stability, dispersion, and the patterning itself of the scQDs.

Linnaeite Mineral for NIR Light-Triggered Disruption of Alzheimer's Pore-Forming Aβ Oligomers

Minerals in the Earth's crust have contributed to the natural functioning of ecosystems via biogeochemical interactions. Linnaeite is a cobalt sulfide mineral with a cubic spinel structure that promotes charge transfer reactions with its surroundings. Here we report the hidden feature of linnaeite mineral to dissociate Alzheimer's β-amyloid (Aβ) oligomers under near-infrared (NIR) light irradiation. Alzheimer's disease (AD) is a neurodegenerative disorder caused by the abnormal accumulation of self-assembled Aβ peptides in the elderly brain. The β-sheet structured pore-forming Aβ oligomer (βPFO) is the most neurotoxic species exacerbating the symptoms of AD. However, a therapeutic agent that is capable of inactivating βPFO has not yet been developed. Our microscopic and spectroscopic analysis results have revealed that NIR-excited linnaeite mineral can modulate the structure of βPFO by inducing oxidative modifications. We have verified that linnaeite mineral is biocompatible with and has a mitigating effect on the neurotoxicity of βPFO. This study suggests that minerals in nature have potential as drugs to reduce AD pathology.

Metal-Organic Framework-Derived Carbon as a Photoacoustic Modulator of Alzheimer's β-Amyloid Aggregate Structure

Photoacoustic materials emit acoustic waves into the surrounding by absorbing photon energy. In an aqueous environment, light-induced acoustic waves form cavitation bubbles by altering the localized pressure to trigger the phase transition of liquid water into vapor. In this study, we report photoacoustic dissociation of beta-amyloid (Aβ) aggregates, a hallmark of Alzheimer's disease, by metal-organic framework-derived carbon (MOFC). MOFC exhibits a near-infrared (NIR) light-responsive photoacoustic characteristic that possesses defect-rich and entangled graphitic layers that generate intense cavitation bubbles by absorbing tissue-penetrable NIR light. According to our video analysis, the photoacoustic cavitation by MOFC occurs within milliseconds in the water, which was controllable by NIR light dose. The photoacoustic cavitation successfully transforms robust, β-sheet-dominant neurotoxic Aβ aggregates into nontoxic debris by changing the asymmetric distribution of water molecules around the Aβ's amino acid residues. This work unveils the therapeutic potential of NIR-triggered photoacoustic cavitation as a modulator of the Aβ aggregate structure.

Theoretical Study of LED Operating in Noncarrier Injection Mode

Non-carrier injection (NCI) mode is an emerging driving mode for light-emitting diodes (LEDs) with numerous advantages. Revealing the relationship between the current and the applied alternating voltage in mathematical formulas is of great significance for understanding the working mechanism of NCI–LEDs and improving device performance. In this work, a theoretical model of the relationship between NCI–LED current and time-varying voltage is constructed. Based on the theoretical model, the real-time current is derived, which is consistent with the experimental results. Key parameters that can improve device performance are discussed, including voltage amplitude, frequency, equivalent capacitance, and LED reverse current. The theory presented here can serve as an important guidance for the rational design of the NCI–LEDs.