The one-step acetalization reaction for construction of hyperbranched and biodegradable luminescent polymeric nanoparticles with aggregation-induced emission feature

Loading curcumin on hyperbranched polymers functionalized Zein via the phenol-yne click reaction as pH-responsive drug delivery system for chemotherapy and photodynamic therapy

Zein and its complexes have been considered as promising carriers for encapsulating and delivering various biological active ingredients, however, there still have some issues about Zein-based drug delivery systems should be considered, including poor colloidal stability, low drug encapsulation efficiency as well as rapid initial drug release, and uncontrollable release. In this work, we reported for the first time that hyperbranched polymers (HPG) functionalized Zein with terminal alkyne (Zein-HPG-PA) can be used for loading anticancer agent curcumin (CUR) via a facile phenol-yne click reaction. The resultant product (Zein-HPG-PA@CUR) displays high drug loading capacity, small particle size and excellent water dispersibility. More importantly, almost no CUR was released from Zein-HPG-PA@CUR under pH 7.4 and the cargo will be gradually released under acidic environment. As compared with free CUR, Zein-HPG-PA@CUR shows considerable cytotoxicity towards MDA-MB-231 cells under dark environment, while the cytotoxicity was significantly enhanced upon light-irradiation, implying great potential of Zein-HPG-PA@CUR for cancer treatment. Considered the above aspects, we believe that this work should be of significant impact on the biomedical applications of Zein, especially for fabrication of Zein-based responsive drug delivery systems.

Aggregation-induced emission luminogens for intracellular bacteria imaging and elimination

Intracellular bacterial infections are a serious threat to human health due to their ability to escape immunity and develop drug resistance. Recent attention has been devoted to identifying and ablating intracellular bacteria with fluorescence probes. Aggregation-induced emission luminogens (AIEgens) photosensitizers as fluorescence probes possess excellent photostability and rapid response, which have emerged as powerful fluorescent tools for intracellular bacterial detection and antibacterial therapy. This review is intended to highlight the current advances in AIEgens on intracellular bacteria imaging and elimination, which covers topics from intracellular AIE mechanism, intracellular bacteria imaging of AIEgens to the elimination of intracellular bacteria with AIEgens. AIEgens utilized different interactions to detect intracellular bacteria, emitting bright light due to restricted intramolecular movement to visualize intracellular bacteria. Photosensitive AIEgens generate reactive oxygen species (ROS) in the aggregate state to elimate intracellular bacteria. Moreover, the prospects and application of AIEgens in intracellular bacteria imaging and elimination are also discussed, which provides insights for the development of AIE-based diagnostic and therapeutic materials and technologies.

Recent Advances on Fabrication of Polymeric Composites Based on Multicomponent Reactions for Bioimaging and Environmental Pollutant Removal

As the core of polymer chemistry, manufacture of functional polymers is one of research hotspots over the past several decades. Various polymers are developed for diverse applications due to their tunable structures and unique properties. However, traditional step-by-step preparation strategies inevitably involve some problems, such as separation, purification, and time-consuming. The multicomponent reactions (MCRs) are emerging as environmentally benign synthetic strategies to construct multifunctional polymers or composites with pendant groups and designed structures because of their features, such as efficient, fast, green, and atom economy. This mini review summarizes the latest advances about fabrication of multifunctional fluorescent polymers or adsorptive polymeric composites through different MCRs, including Kabachnik-Fields reaction, Biginelli reaction, mercaptoacetic acid locking imine reaction, Debus-Radziszewski reaction, and Mannich reaction. The potential applications of these polymeric composites in biomedical and environmental remediation are also highlighted. It is expected that this mini-review will promote the development preparation and applications of functional polymers through MCRs.

Solid solid phase change (SSPC) chitosan-g-mPEG fiber with improved mechanical performance via in-situ wet spinning process

Nowadays, environment-friendly and sustainable polymers have aroused great research attention, due to serious pollution caused by nondegradable and nonrenewable polymer waste. In this paper, chitosan (CS) grafted polyethylene glycol monomethyl ether (mPEG) (CS-g-mPEG) fiber, with solid-solid phase change (SSPC) behavior and improved mechanical performance, were prepared successfully by in-situ wet spinning process. The tensile strength of CS-g-mPEG fiber reached 1.36 cN/dtex, increased by more than 50 % contrasted with CS fiber, due to the enhancement of molecular entanglement and hydrogen bonding interactions. Particularly, CS-g-mPEG fiber with stable shape could actively absorb heat as ambient temperature above 46 °C, then would release heat as ambient temperature below 26 °C. So, the human body will not feel too cold or heat. Thus, this work do not only give a continuous process of fabricating SSPC CS-g-mPEG fiber for industry, but also provides an important choice for smart textiles.

Advances in amphiphilic hyperbranched copolymers with an aliphatic hyperbranched 2,2-bis(methylol)propionic acid-based polyester core

Amphiphilic hyperbranched copolymers with an aliphatic hyperbranched 2,2-bis(methylol)propionic acid-based polyester core were highlighted.

Water-dispersible astaxanthin-rich nanopowder: preparation, oral safety and antioxidant activity in vivo

In this research, astaxanthin-rich nanopowder was prepared by nanoencapsulation and freeze-drying techniques with enhanced bioavailability and antioxidant activities. The nanopowder showed a maximum solubility of 230 mg mL-1 with an astaxanthin content as high as 2.9%. Compared with free astaxanthin, the astaxanthin-loaded nanopowder exhibited a more efficient antioxidant effect: an oral dose of 0.9 mg per kg BW significantly reduced the malondialdehyde and protein carbonyl contents, and increased the glutathione content as well as the superoxide dismutase activities in alcohol-induced acute hepatic injured mice, and maintained these oxidative stress indicators at a normal level for a longer period when treated with nanoencapsulated-astaxanthin than free astaxanthin. Simulated gastrointestinal tract studies demonstrated that the nanopowder with pH and DNase I-dependent dissociation properties delivered astaxanthin efficiently to the small intestine. Astaxanthin-rich nanopowder with a dose as high as 2.4 mg per kg BW (equivalent to astaxanthin) showed no chronic toxicity to mice in terms of hematology and pathological histology, indicating its impressive biocompatibility for biomedical applications. Pharmacokinetics and relative bioavailability (207%) of the nanopowder further proved that DNA/chitosan nanocarriers significantly improved the delivery efficiency of astaxanthin. With enhanced bioavailability and antioxidant activities, this novel type of astaxanthin-loaded nanopowder is expected to find broad application in the food and drug industry.

Simultaneous recognition of cysteine and cytosine using thiophene-based organic nanoparticles decorated with Au NPs and bio-imaging of cells

Biomolecules like cysteine and cytosine play a significant role in many physiological processes, and their unusual level in biological systems can lead to many diseases including cancer. Indeed, the need for selective detection of these moieties by a fluorescence probe is imperative. Thus, thiophene based Schiff N,N'-bis(thiophene-2-ylmethylene)thiophenemethane (BMTM) was synthesized and then characterized using several analytical techniques before converting it into organic nanoparticles (ONPs). Then, fluorescent organic inorganic nanohybrids (FONs) were obtained after decorating ONPs with AuNPs to yield BMTM-Au-ONPs (FONPs). The morphology of the particles, analyzed using a Transmission Electron Microscope (TEM), shows that AuNPs were embedded with low density organic matter (ONPs). FONPs were employed to recognize cysteine and cytosine simultaneously. No interference was observed from other moieties such as guanine, uracyl, NADH, NAD, ATP, and adenine during the detection. It means that the intensity of the fluorescence signal was significantly changed (enhanced for cytosine and quenched for cysteine). So, FONPs were used to detect cysteine and cytosine in real samples, like Saccharomyces cerevisiae cells. As expected, no considerable fluorescence signal for cysteine was observed, while for cytosine, strong fluorescence signals were detected in the cells. DFT was used to explain the interaction of FONPs with cysteine or cytosine.

Photoactivation of Aggregation-Induced Emission Molecules for Fast and Efficient Synthesis of Highly Fluorescent Single-Chain Nanoparticles

Single-chain nanoparticles (SCNPs) are ultrasmall soft nanomaterials constructed via intrachain cross-linking of individual precursor polymer chains, with promising prospects for nanomedicine, catalysis, and sensing, among other different fields. SCNPs are versatile building blocks for the construction of new fluorescent probes with ultrasmall size, higher brightness, and better photostability than previous particle-based systems. Herein, we report on a new, fast, and efficient method to produce SCNPs with intense fluorescence emission in solution which is based on the photoactivation of appropriate aggregation-induced emission (AIE) cross-linking molecules containing azide functional groups. Remarkably, the presence of the azide moiety-that can be transformed to highly reactive nitrene species upon UV irradiation-was found to be essential for the SCNPs to display intense fluorescence emission. We attribute the fluorescence properties of the SCNPs to the immobilization of the initially nonfluorescent AIE molecules via intrachain cross-linking upon photoactivation. Such cross-linking-induced immobilization process activates the AIE mechanism and, hence, leads to fluorescent SCNPs in both solution and solid state.

Sericin-chitosan doped maleate gellan gum nanocomposites for effective cell damage in Mycobacterium tuberculosis

Polysaccharides are increasingly used as biodegradable nanocarrier to selectively deliver therapeutic agents to specific cells. In this study, maleate gellan gum (MA-GG) formed by addition of free radical polymerizable groups, which can be polymerized presence of acetone to design biodegradable three-dimensional networks, were synthesized by esterification. Natural silk sericin was grafted over the maleate gellan gum surface. Maleate Gellan Gum- Silk Sericin-Chitosan (MA-GG-SS-CS) nanocomposites loaded with rifampicin (RF) and pyrazinamide (PZA) to overcome the problems associated with Tuberculosis (TB) therapy. The pH responsive behavior of gellan gum nanocomposites was reposed by silk sericin and exhibited sustained release of 79% RF and 82% PZA for 120 h at pH 4.0. The designed formulations shows higher antimycobacterial activity and rapid delivery of drugs at TB infected macrophage. Nanomaterial effectively aggregated and internalized into the bacterial cells and MH-S cells. Dual drug release inside the cells makes damage in the cell membrane. Green nanocomposites studies pave the way for important use of macromolecules in pulmonary delivery TB drugs.

One-pot ultrafast preparation of silica quantum dots and their utilization for fabrication of luminescent mesoporous silica nanoparticles

Silica quantum dots (SiQDs) and their luminescent composites have displayed great potential for biomedical applications owing to their chemical inert and low cost. In this work, we report a facile, cost-effective and ultrafast strategy to prepare a stable luminescent SiQDs using N-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) and salicylaldehyde as precursors for the first time. These luminescent SiQDs were further utilized for fabrication of luminescent mesoporous silica nanoparticles (MSNs) through direct encapsulation of SiQDs by MSNs. The novel synthetic and modified SiQDs uses commercial raw materials and the entire reaction can be completed within 30 s. The successful preparation of SiQDs and SiQDs@MSNs were characterized by various characterization equipments. The cell viability as well as cell uptake behavior of SiQDs@MSNs were also examined to evaluate their potential for biomedical applications. We demonstrated that these SiQDs@MSNs are low toxicity and of great potential for biological imaging. Based on the above results, we believe that these SiQDs@MSNs should be novel and promising candidates for biomedical applications owing to their intense fluorescence, biocompatibility and high specific surface areas.

Fluorescence probes based on AIE luminogen: application for sensing Hg2+ in aqueous media and cellular imaging

S1 and S2 could be applied for sensing Hg²⁺ in aqueous media and cellular imaging with remarkable AIEE.