A gelatin methacryloyl (GelMA) treated with gallic acid and coated with specially designed nanoparticles derived from ginseng enhances the healing of wounds in diabetic rats.

Due to persistent inflammation and oxidative stress reactions, achieving drug absorption in diabetic wounds is challenging. To overcome this problem, our article presents a composite hydrogel, GelMA-GA/DMOG@GDNP, which consists of gelatin methacryloyl (GelMA) treated with gallic acid (GA) and encapsulating ginseng-derived nanoparticles (GDNPs) loaded with dimethyloxallyl glycine (DMOG). The composite hydrogel demonstrates excellent biocompatibility. In laboratory settings, the hydrogel inhibits the production of nitric oxide synthase 2 (iNOS) in mouse immune cells (RAW264.7 cells), enhances the growth and migration of mouse connective tissue cells (L929 cells) and human endothelial cells (HUVECs), and promotes tube formation in HUVECs. In a rat model of type 1 diabetes-induced wounds, the composite hydrogel attenuates inflammatory reactions, facilitates the formation of fibres and blood vessels, accelerates wound healing, and elucidates specific pathway mechanisms through transcriptome sequencing. Therefore, the GelMA-GA/DMOG@GDNP hydrogel can serve as a safe and efficient wound dressing to regulate the inflammatory response, promote collagen fiber and blood vessel formation, and accelerate wound healing. These findings suggest that utilizing this multifunctional engineered nanoparticle-loaded hydrogel in a clinical setting may be a promising strategy for diabetic wound healing.

Highly Active Coreactant-Capped and Water-Stable 3D@2D Core-Shell Perovskite Quantum Dots as a Novel and Strong Self-Enhanced Electrochemiluminescence Probe.

Self-enhanced electrochemiluminescence (ECL) probes have attracted more and more attention in analytical chemistry for their significant simplification of the ECL sensing operation while improving the ECL sensing sensitivity. However, the development and applications of self-enhanced ECL probes are still in their infancy and mainly suffer from the requirement of a complicated synthesis strategy and relatively low self-enhanced ECL activity. In this work, we took advantage of the recently emerged perovskite quantum dots (PQDs) with high optical quantum yields and easy surface engineering to develop a new type of PQD-based self-enhanced ECL system. The long alkyl chain (C18) diethanolamine (i.e., N-octadecyldiethanolamine (ODA)) with high ECL coreactant activity was selected as a capping ligand to synthesize an ODA-capped PQD self-enhanced ECL probe. The preparation of the coreactant-capped PQDs is as simple as for the ordinary oleylamine (OAm)-capped PQDs, and the obtained ODA-capped PQDs exhibit very strong self-enhanced ECL activity, 82.5 times higher than that of traditional OAm-capped PQDs. Furthermore, the prepared ODA-PQDs have a unique nanostructure (ODA-CsPbBr3@CsPb2Br5), with the highly emissive 3D CsPbBr3 PQD as the core and the water-stable 2D CsPb2Br5 as the shell, which allows ODA-PQDs to be very stable in aqueous media. It is envisioned that the prepared ODA-3D@2D PQDs with the easy preparation method, strong self-enhanced ECL, and excellent water stability have promising applications in ECL sensing.

Encapsulation of Pure Water-Stable Perovskite Nanocrystals (PNCs) into Biological Environment-Stable PNCs for Cell Imaging.

Recently emerging perovskite nanocrystals (PNCs) are very attractive fluorescence nanomaterials due to their very narrow emission peak, tunable wavelength, and extremely high quantum yield, but their chemosensing, biosensing and bioimaging applications suffer from the poor stability of ordinary PNCs in aqueous media, especially in biological matrices. Recently developed water-stable 2D CsPb2Br5-encapsulated 3D CsPbBr3 PNCs (i.e., CsPbBr3/CsPb2Br5 PNCs) show extremely stable light emission in pure water, but their fluorescence is seriously quenched in aqueous media containing biological molecules due to their chemical reactions. In this work, we used a facile method to encapsulate pure water-stable CsPbBr3/CsPb2Br5 PNCs in water with SiO2 and polyethylene glycol hexadecyl ether (Brij58) into a new kind of biological environment-stable PNCs (CsPbBr3/CsPb2Br5@SiO2-Brij58). The synthesis of the target PNCs can be accomplished in a fast, easy, and green way. The obtained CsPbBr3/CsPb2Br5@SiO2-Brij58 PNCs maintain strong fluorescence emission for a long time, all in pH 7.4 PBS, BSA, and minimum essential medium, exhibiting excellent biological environment stability. Moreover, the developed biological environment-stable PNCs show good biocompatibility and have been successfully used in cell imaging. Overall, the work provides an easy, low-cost, and efficient application of PNCs in bioimaging.

Photochromic Perovskite Nanocrystals for Ultraviolet Dosimetry.

Excessive ultraviolet (UV) radiation has serious damage to human's health, therefore the development of visible, portable, and wearable sensor for monitoring UV radiation, especially the cumulative UV dosage, is highly desired but full of challenges. Herein, a wearable and flexible UV dosimeter based on photochromic perovskite nanocrystals (PNCs) is designed. The obtained CsPbCl3 PNCs dispersed in dibromomethane (PNCs-DBM) undergo continuous, vivid, and multiple (from very weak purple to blue, cyan, and finally strong green) color change in response to UV radiation. It is demonstrated that the UV-induced degradation of DBM and subsequent anion-exchange reaction between CsPbCl3 and Br- , play a crucial role in the color change of PNCs-DBM. The properties of continuous fluorescence color change and enhanced fluorescence intensity enable the construction of sensitive and visible UV dosimeter. Furthermore, by integrated photochromic PNCs with flexible bracelet or PDMS substrate, a wearable UV sensor or a multi-indicator array for the detection of solar UV dosage is developed. This work may advance the fundamental understanding about photochromic perovskite, and show promising application of perovskite nanomaterials in easily fabricated, low-cost, visualized, and wearable solar UV dosimeter.

Facile Synthesis of Oxidized Boron Nanosheets for Chemo- and Biosensing.

As recently emerging nanomaterials, boron nanosheets (BNSs) have attracted more and more attention in various fields such as supercapacitors, photodetectors, bioimaging, and electrocatalysis due to their advantages of good biological compatibility, environmental friendliness, and good electro-optical properties. However, the study and application of BNSs in chemical and biological sensing are still in the infant stage, mainly due to the requirement of complicated, high-cost, and time-consuming preparation strategies. In this work, a new class of BNSs, namely oxidized-BNSs (i.e., ox-BNSs), were easily and rapidly synthesized by chemically treating boron powder with diluted HNO3 in a very short time (less than 15 min). The composition, morphology, optical property, and peroxidase mimetic activity of obtained ox-BNSs were investigated in detail. The prepared ox-BNSs were several-layered nanosheets with abundant oxygen-containing groups, emitted blue fluorescence, and possessed good intrinsic peroxidase mimetic activity, based on which a sensitive and selective colorimetric sensor was developed for detection of H2O2 and glucose. The new easy preparation strategy and good sensing performances of the prepared ox-BNSs would greatly stimulate the study and application of BNSs in chemo- and biosensing.

Anion Exchanges of Water-Stable Perovskite Nanocrystals in the Pure Water Phase and Applications in Detecting Halide Ions via a Smartphone-Based Sensing Platform.

Recently, the newly emerging lead halide perovskite nanocrystals (PNCs) have been intensely researched in many fields, such as light-emitting diodes (LEDs), solar cells, lasers, and display devices. The extremely high fluorescence quantum yield (near 100%) of PNCs over classic fluorescent materials would enable good applications of PNCs in sensing. However, the study on PNCs for bio- and chemical sensing, especially for detecting targets that exist in aqueous medium, faces great challenges due to the well-known instability of PNCs in polar solvents, especially water. Although the encapsulation of polymers or inorganic materials can efficiently protect PNCs from decomposition in aqueous solution, the sensing based on the interaction between PNCs and targets is severely hindered by the compact protection coating at the surfaces of PNCs. In this work, novel water-dispersed PNCs (W-PNCs), i.e., CsPbBr3@CsPb2Br5 PNCs, with strong fluorescence and excellent water stability were synthesized from OAm-capped CsPbBr3 PNCs by a simple "oil-solid-water" phase transition. The W-PNCs without being encapsulated with compact polymers or inorganic materials can sensitively and stably sense targets in the pure water phase via direct chemical reactions. For the first time, ion exchanges between PNCs and halide ions and their effects on the fluorescence wavelength of PNCs were investigated in the pure water phase, on the basis of which a new, visualized, selective, and sensitive smartphone-based sensing platform for halide ions has been established by the integration of the conveniently prepared W-PNC nanoprobe and the portable mobile phone. It is envisioned that the uncoated but extremely water-stable and highly fluorescent W-PNCs have promising applications in chemical sensing, biosensing, and bioimaging of targets in aqueous medium.

Hydrochromic Perovskite System with Reversible Blue-Green Color for Advanced Anti-Counterfeiting.

The intrinsic instability of halide perovskites toward to external stimulus, has created a competitive advantage for designing stimuli-responsive materials. However, the external environment tuning reversibly fluorescence emission of perovskite system is still limited. In this work, humidity is verified to act as a new option to modulate the emission properties of mixed-halide perovskite. The perovskite nanocrystals (PNCs) photoirradiated in dichloromethane are easily and stably redispersed in water, and emit bright fluorescence which is quite different from the original. Moreover, the perovskites confined on glass slide can reversibly switch their fluorescence between blue and green colors under moisture. It is demonstrated that the factors of different solubilities of CsCl and CsBr in water, the structural transformation of perovskites and the confine of glass matrix play key roles in the reversible transformation. Finally, the combination of hydrochromic CsPb(Brx Cly )3 and water-resistant CsPb(Brx Cly )3 -polymethyl methacrylate have been applied in advanced anti-counterfeiting, which greatly improves the information security. This work not only give an insight into the effects of humidity on fluorescence and structures of PNCs, but also offer a new class of hydrochromic PNCs materials based on reversible emission transformation for potential application in sensors, anti-counterfeiting and information encryption.

The engineered CRISPR-Mb2Cas12a variant enables sensitive and fast nucleic acid-based pathogens diagnostics in the field.

Existing CRISPR/Cas12a-based diagnostic platforms offer accurate and vigorous monitoring of nucleic acid targets, but have the potential to be further optimized for more efficient detection. Here, we profiled 16 Cas12a orthologs, focusing on their trans-cleavage activity and their potential as diagnostic enzymes. We observed the Mb2Cas12a has more robust trans-cleavage activity than other orthologs, especially at lower temperatures. An engineered Mb2Cas12a-RRVRR variant presented robust trans-cleavage activity and looser PAM constraints. Moreover, we found the existing one-pot assay, which simultaneously performed Recombinase Polymerase Amplification (RPA) and Cas12a reaction in one system, resulted in the loss of single-base discrimination during diagnosis. Therefore, we designed a reaction vessel that physically separated the RPA and Cas12a steps while maintaining a closed system. This isolated but closed system made diagnostics more sensitive and specific and effectively prevented contamination. This shelved Mb2Cas12a-RRVRR variant-mediated assay detected various targets in less than 15 min and exhibited equal or greater sensitivity than qPCR when detecting bacterial pathogens, plant RNA viruses and genetically modified crops. Overall, our findings further improved the efficiency of the current CRISPR-based diagnostic system and undoubtedly have great potential for highly sensitive and specific detection of multiple sample types.

Highly Electrochemiluminescent Cs4PbBr6@CsPbBr3 Perovskite Nanoacanthospheres and Their Application for Sensing Bisphenol A.

Perovskite quantum dots (PQDs) as recently emerging electrochemiluminescence (ECL) luminophores have been paid much attention due to their good ECL activity, narrow ECL spectra, and easy preparation. However, the PQDs used for ECL sensing were mainly inherited from those PQDs prepared as strong fluorescence (FL) luminophores, which would limit the finding of highly ECL PQDs for sensing due to the very different mechanisms in generating excited-state luminophores between ECL and FL. In order to obtain highly electrochemiluminescent PQDs, for the first time we proposed to synthesize PQDs for ECL sensing rather than for FL-based analysis by optimizing the synthesis conditions. It was revealed that the volume of the precursor solution, the concentrations of CsBr and PbBr2, the amount of capping reagents, and the synthesis reaction temperature all significantly affect the ECL activity of PQDs. On the basis of the optimization of the synthesis conditions, we obtained a new type of PQDs with high ECL activity. The new PQDs were characterized by several technologies, such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive X-ray spectrum, to be the hybrids of 3D PQDs (CsPbBr3) and 0D PQDs (Cs4PbBr6) with unique morphologies, i.e., Cs4PbBr6@CsPbBr3 PQD nanoacanthospheres (PNAs), in which Cs4PbBr6 was as the core and CsPbBr3 served as the shell. The obtained Cs4PbBr6@CsPbBr3 PNAs had much higher (>4 times) ECL activity than the prevailing 3D (CsPbBr3) PQDs. Finally, the novel Cs4PbBr6@CsPbBr3 PNAs have been applied for the ECL sensing of bisphenol A (BPA), showing a promising application of the highly electrochemiluminescent PQDs in analytical chemistry.

Phototriggered color modulation of perovskite nanoparticles for high density optical data storage.

Photoresponsive luminescent materials (PLMs) have attracted much attention in various optoelectronic fields, especially in optical data storage. Multi-wavelength (N-wavelength) based optical storage is a promising approach to increase the data storage density, but its current application is limited by the fact that most PLMs have only two-wavelength emissive states after certain light excitation, which requires simultaneous use of several PLMs and different irradiation light sources. In this study, we discovered that the wavelength of perovskite nanocrystals (PNCs) in the presence of dichloromethane (DCM) could be continuously and precisely tuned over a very wide color range (from red to violet) with the help of a single UV light source. The changes in crystal structures and optical properties of PNCs during UV irradiation were investigated in detail; the effects of capping ligand, solvent, UV irradiation power and time were evaluated, and the mechanism of UV triggered PNC fluorescence change was studied and is discussed. Finally, the applicability of PNCs/DCM film in N-wavelength-based high-density optical data storage was verified.

Effects of Structural and Compositional Changes of Nanochloropsis oceania after Enzyme Treatment on EPA-Rich Lipids Extraction.

Improved methods for the extraction of eicosapentaenoic acid (EPA), an essential and economically important polyunsaturated fatty acid, are urgently required. However, lipid extraction rates using food-grade solvents such as ethanol are usually low. To improve the ethanol-based extraction rate, and to elucidate the relevant mechanisms, we used cellulase and laccase to treat powdered Nannochloropsis, one of the most promising microalgal sources of EPA. Cellulase and laccase synergistically increased lipid yields by 69.31% and lipid EPA content by 42.63%, by degrading the amorphous hemicellulose and cellulose, improving crystallinity, and promoting the release and extraction of lysodiacylglyceryltrimethylhomoserine. Scanning electron microscopy showed that cell morphology was substantially altered, with cell-wall rupture, loss of cell boundaries, and the release of intracellular substances. In conclusion, Nannochloropsis lipid yields may be directly linked to cell-wall hemicellulose structure, and enzymatic treatment to alter this may improve lipid yields.