Detection of Alpha Fetoprotein Based on AIEgen Nanosphere Labeled Aptamer Combined with Sandwich Structure of Magnetic Gold Nanocomposites.

As a biomarker, alpha-fetoprotein (AFP) is valuable for detecting some tumors in men, non-pregnant women, and children. However, the detection sensitivity in some methods needs to be improved. Therefore, developing a simple, reliable, and sensitive detection method for AFP is important for non-malignant diseases. An aptamer binding was developed based on aggregation-induced emission luminogen (AIEgen) nanosphere labeled with Fe3O4@MPTMS@AuNPs. AFP was detected with a sandwich structure of AuNPs magnetic composite particles. An aggregation-induced emission (AIE) molecule and polystyrene (PS) nanosphere complex were assembled, enhancing the fluorescence and improving the sensitivity of detection. The limit of detection (LOD) was at a given level of 1.429 pg/mL, which can best be achieved in serum samples. Finally, the results obtained showed the complex to be promising in practical applications.

Facile fabrication of transparent lignin sphere/PVA nanocomposite films with excellent UV-shielding and high strength performance.

With the rapid development of human society, more and more concerns are directed to utilization of environment-friendly and biodegradable materials. To meet this demand, we fabricated an environment-friendly poly (vinyl alcohol) (PVA)/lignin nanocomposite films with excellent UV-shielding and visible-transparent performance. The lignin-based nanosphere (LNSs) were prepared via self-assembly and uniformly distributed in the PVA matrix by forming strong hydrogen bonds with PVA matrix. With the introduction of LNSs into PVA matrix, the various performance such as tensile strength, thermal stability, and UV-shielding of PVA/Lignin nanocomposite films were enhanced. Amazingly, the UV-shielding results revealed that UVB (320-275 nm) and UVC (275-200 nm) were completely shielded and UVA (400-320 nm) was mostly shielded with addition of 4 wt% LNSs. Meanwhile, the tensile strength of the nanocomposite film was dramatically enhanced, in which the strength increased from 76 MPa to 112 MPa. Since both lignin and PVA were biodegradable materials, this work provides a simple and valuable method for the preparation of biodegradable and functional films.

Effectuation of loading a natural acetyl carnosine derivative within a promising cross-linked cyclodextrin spongey-like nanospheres on Physicochemical characterization and release behavior.

This study centered on the ability of the cross-linked nano-sponge system to load the drug and to improve its physicochemical and dissolution properties. A spectrophotometric method was used to determine the wavelength of maximum absorbance of the drug. The ultrasonic-assisted synthesis method was used for nano-sponge preparation. Solution-state interactions, encapsulation efficiency and production yield, and in-vitro release were also investigated. Nano-sponges were characterized by Transmission Electron-Microscopy (TEM), Scanning Electron-Microscopy (SEM), Fourier Transform-Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), and X-Ray Diffractometry (X-RD) studies. The maximum absorption wavelength of N-acetyl-L-carnosine was found to be at 210 nm. Solution-state interaction studies revealed a bathochromic shift. The production yield of nano-sponges ranged from 59.58% to 72.54%. In-vitro release study showed a sustained drug release for 228 hours. TEM images showed regular spherical shapes and sizes of nano-sponges. Their average particle size ranged from 28 nm to 79.2 nm. DSC data documented the drug-polymer interactions. FT-IR determined the presence of functional groups. X-RD showed the physicochemical characteristics of nano-sponges. Proving successful development of N-acetyl-L-carnosine polymeric nano-sponge system with a suitable drug delivery over an extended period beside a noticeable improvement in the physicochemical characterization.

Preparation of cellulose nanospheres via combining ZnCl2·3H2O pretreatment and p-toluenesulfonic hydrolysis as a two-step method.

Spherical nanocelluloses, also known as cellulose nanospheres (CNS), have controllable morphology and have shown advantages as green template material, emulsion stabilizer. Herein, CNS were prepared via a new two-step method, first pretreatment of microcrystalline cellulose (MCC) using ZnCl2·3H2O and then acid hydrolysis of regenerated cellulose (RC) via p-toluenesulfonic acid (p-TsOH). The shape, size, crystallinity of MCC were changed, and nubbly RC with smallest size (942 nm) was obtained after 2 h pretreatment by ZnCl2·3H2O. CNS with high 61.3% yield were produced after acid hydrolysis (67 wt% p-TsOH) of RC at 80 °C, 6 h. The analysis of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) showed that CNS had an average diameter of 347 nm. CNS were present in precipitate after high-speed centrifugation, due to the high Zeta potential of -12 mV and large size. The structure of CNS was tested by Fourier Transfer Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Nuclear Magnetic Resonance (NMR), CNS had high crystallinity (cellulose II) of 61%. Thermal Gravimetric Analysis (TGA) indicated that CNS had high thermal stability (Tonset 303.3 °C, Tmax 332 °C). CNS showed poor re-dispersibility in water/ethanol/THF, 1 wt% CNS could be dissolved in ZnCl2·3H2O. 7.37% rod-like CNC were obtained after 6 h hydrolysis. FTIR proved that p-TsOH was recovered by re-crystallization. This study provided a novel, sustainable two-step method for the preparation of spherical CNS.

Cancer Cell-Membrane Biomimetic Boron Nitride Nanospheres for Targeted Cancer Therapy.

PURPOSE: Nanomaterial-based drug-delivery systems allowing for effective targeted delivery of smallmolecule chemodrugs to tumors have revolutionized cancer therapy. Recently, as novel nanomaterials with outstanding physicochemical properties, boron nitride nanospheres (BNs) have emerged as a promising candidate for drug delivery. However, poor dispersity and lack of tumor targeting severely limit further applications. In this study, cancer cell-membrane biomimetic BNs were designed for targeted anticancer drug delivery. METHODS: Cell membrane extracted from HeLa cells (HM) was used to encapsulate BNs by physical extrusion. Doxorubicin (Dox) was loaded onto HM-BNs as a model drug. RESULTS: The cell-membrane coating endowed the BNs with excellent dispersibility and cytocompatibility. The drug-release profile showed that the Dox@HM-BNs responded to acid pH, resulting in rapid Dox release. Enhanced cellular uptake of Dox@HM-BNs by HeLa cells was revealed because of the homologous targeting of cancer-cell membranes. CCK8 and live/dead assays showed that Dox@HM-BNs had stronger cytotoxicity against HeLa cells, due to self-selective cellular uptake. Finally, antitumor investigation using the HeLa tumor model demonstrated that Dox@HM-BNs possessed much more efficient tumor inhibition than free Dox or Dox@BNs. CONCLUSION: These findings indicate that the newly developed HM-BNs are promising as an efficient tumor-selective drug-delivery vehicle for tumor therapy.

Nanocellulose as template to prepare rough-hydroxy rich hollow silicon mesoporous nanospheres (R-nCHMSNs) for drug delivery.

Drug-delivery technology is an effective way to promote drug absorption and efficacy. Mesoporous hollow silica material and small-molecule drug ibuprofen were used as a carrier model and as model drug, respectively. By quantum chemical calculation (density functional theory and frontier orbital theory), it was found that the content of geminal silanols on the material surface played a decisive role in the release of the different drugs. The rough hollow materials are easily adsorbed and have a large loading capacity, and so we fabricated a mesoporous hollow silica material (R-nCHMSNs) with a rough surface and rich geminal silanols by using hydroxyl-rich nanocellulose as a template. The content and types of hydroxyl groups on the material surface were studied by 29Si NMR. The loading and delivery of ibuprofen and lysozyme were studied in detail. Materials with rich geminal silanols exhibited excellent delivery properties for different drugs, which shows great potential and research value for drug delivery.

Cytotoxicity Effects of Curcumin Loaded on Chitosan Alginate Nanospheres on the KMBC-10 Spheroids Cell Line.

PURPOSE: Breast cancer is one of the most lethal types of cancer in women. Curcumin showed therapeutic potential against breast cancer, but applying that by itself does not lead to the associated health benefits due to its poor bioavailability, which appears to be primarily due to poor absorption, rapid metabolism, and rapid elimination. Moreover, poor water solubility of curcumin causes accumulation of a high concentration of curcumin and so decrease its permeability to the cell. Many strategies are employed to reduce curcumin metabolism such as adjuvants and designing novel delivery systems. Therefore, in this study sodium alginate and chitosan were used to synthesize the hydrogels that are known as biocompatible, hydrophilic and low toxic drug delivery systems. Also, folic acid was used to link to chitosan in order to actively targetfolate receptors on the cells. METHODS: Chitosan-ß-cyclodextrin-TPP-Folic acid/alginate nanoparticles were synthesized and then curcumin was loaded on them. Interaction between the constituents of the particles was characterized by FTIR spectroscopy. Morphological structures of samples were studied by FE-SEM. Release profile of curcumin was determined by dialysis membrane. The cytotoxic test was done on the Kerman male breast cancer (KMBC-10) cell line by using MTT assay. The viability of cells was detected by fluorescent staining. Gene expression was investigated by real-time PCR. RESULTS: The encapsulation of curcumin into nano-particles showed an almost spherical shape and an average particle size of 155 nm. In vitro cytotoxicity investigation was indicated as dose-respond reaction against cancer breast cells after 24 h incubation. On the other hand, in vitro cell uptake study revealed active targeting of CUR-NPs into spheroids. Besides, CXCR 4 expression was detected about 30-fold less than curcumin alone. The CUR-NPs inhibited proliferation and increased apoptosis in spheroid human breast cancer cells. CONCLUSION: Our results showed the potential of NPs as an effective candidate for curcumin delivery to the target tumor spheroids that confirmed the creatable role of folate receptors.

Construction of hypercrosslinked polymers for high-performance solid phase microextraction of phthalate esters from water samples.

Design and synthesis of novel coatings for solid phase microextraction (SPME) is urgently needed for sample pretreatment. In this study, three hypercrosslinked polymers (HCPs) were constructed by the facile Friedel-Crafts alkylation reactions between tetraphenylethylene (TPE) and 1,4-bis(chloromethyl)benzene (BCMB), 4,4'-bis(chloromethyl)-1,1'-biphenyl (BCMBP), and cyanuric chloride (CC), respectively. The newly-synthesized HCPs were employed as SPME coatings for the extraction of phthalate esters (PAEs). Various parameters influencing the SPME efficiencies, including extraction time and temperature, ionic strength, stirring rate, desorption temperature and time were optimized. Under the optimal conditions, low limits of detection (0.003-0.033 µg L - 1), wide linearity (0.01-10 µg L - 1) and good repeatability (4.1-9.3%) were achieved. The HCPs-based SPME method was successfully applied for the determination of eight PAEs in environmental water and bottled water samples with recoveries from 75.3% to 116%. This method provides a good alternative for monitoring trace level of PAEs in water samples.

Preparation of Ag Nanoclusters-Modified Non-Sintered Silica Ceramic-Like Nanosheet for Removing Dyes and Bacteria from Water.

PURPOSE: Worldwide water contamination treatment and water security are essential for all living organisms. Among various water contaminants, dye, and bacteria pollution needs to be solved urgently. METHODS AND RESULTS: In this work, a ceramic sheet from monodisperse, porous silica nanospheres (SiO2 NSs) with an average diameter of 220 was prepared. The prepared SiO2 ceramic sheets were investigated as a "filtration" material in removing dyes (alcian blue, AB; and methylene blue, MB) and bacteria (E. coli and S. aureus). The obtained sheets had efficient adsorption efficiency of 98.72% (for AB) and 97.35% (for MB), and a high adsorption capacity for AB is 220 (mg/g), for MB is 176 (mg/g). Furthermore, these SiO2 ceramic sheets had a high recycling capability for removing dyes by calcination. Being modified by Ag nanoclusters, the ceramic sheets present a strong bactericidal function. CONCLUSION: Our results demonstrated that the obtained SiO2 non-sintered ceramic sheets is rapid and efficient in the filtration of dyes and bacteria from polluted water.

Stabilization and improved properties of Salipaludibacillus agaradhaerens alkaline protease by immobilization onto double mesoporous core-shell nanospheres.

In this study, serine alkaline protease from halotolerant alkaliphilic Salipaludibacillus agaradhaerens strain AK-R was purified and immobilized onto double mesoporous core-shell silica (DMCSS) nanospheres. Covalent immobilization of AK-R protease onto activated DMCSS-NH2 nanospheres was more efficient than physical adsorption and was applied in further studies. DMCSS-NH2 nanospheres showed high loading capacity of 103.8 µg protein/mg nanospheres. Relative to free AK-R protease, the immobilized enzyme exhibited shifts in the optimal temperature and pH from 60 to 65 °C and pH 10.0 to 10.5, respectively. While the soluble enzyme retained 47.2% and 9.1% of its activity after treatment for 1 h at 50 and 60 °C, the immobilized protease maintained 87.7% and 48.3%, respectively. After treatment for 2 h at pH 5 and 13, the immobilized protease maintained 73.6% and 53.4% of its activity, whereas the soluble enzyme retained 32.9% and 1.4%, respectively. Furthermore, the immobilized AK-R protease showed significant improvement of enzyme stability in high concentration of NaCl, organic solvents, surfactants, and commercial detergents. In addition, the immobilized protease exhibited a very good operational stability, retaining 79.8% of its activity after ten cycles. The results clearly suggest that the developed immobilized protease system is a promising nanobiocatalyst for various protease applications.

Nondestructive capture, release, and detection of circulating tumor cells with cystamine-mediated folic acid decorated magnetic nanospheres.

Circulating tumor cell (CTC) detection and enumeration have been considered as a noninvasive biopsy method for the diagnosis, characterization, and monitoring of various types of cancers. However, CTCs are exceptionally rare, which makes CTC detection technologically challenging. In the past few decades, much effort has been focused on highly efficient CTC capture, while the activity of CTCs has often been ignored. Here, we develop an effective method for nondestructive CTC capture, release, and detection. Folic acid (FA), as a targeting molecule, is conjugated on magnetic nanospheres through a cleavable disulfide bond-containing linker (cystamine) and a polyethylene glycol (PEG2k) linker, forming MN@Cys@PEG2k-FA nanoprobes, which can bind with folate receptor (FR) positive CTCs specifically and efficiently, leading to the capture of CTCs with an external magnetic field. When approximately 150 and 10 model CTCs were spiked in 1 mL of lysis blood, 93.1 ± 2.9% and 80.0 ± 9.7% CTCs were recovered, respectively. In total, 81.3 ± 2.6% captured CTCs can be released from MN@Cys@PEG2k-FA magnetic nanospheres by treatment with dithiothreitol. The released CTCs are easily identified from blood cells for specific detection and enumeration combined with immunofluorescence staining with a limit of detection of 10 CTC mL-1 lysed blood. Moreover, the released cells remain healthy with high viability (98.6 ± 0.78%) and can be cultured in vitro without detectable changes in morphology or behavior compared with healthy untreated cells. The high viability of the released CTCs may provide the possibility for downstream proteomics research of CTCs; therefore, cultured CTCs were collected for proteomics. As a result, 3504 proteins were identified. In conclusion, the MN@Cys@PEG2k-FA magnetic nanospheres prepared in this study may be a promising tool for early-stage cancer diagnosis and provide the possibility for downstream analysis of CTCs.

Rapid and sensitive determination of neomycin and kanamycin in measles, mumps, and rubella vaccine via high-performance liquid chromatography-tandem mass spectrometry using modified super-paramagnetic Fe3O4 nanospheres.

A simple magnetic dispersive solid-phase extraction (MDSPE) methodology based on mesoporous Fe3O4@ succinic acid nanospheres and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has been developed to determine kanamycin (KNM) and neomycin (NEO) contents in Measles, Mumps, and Rubella (MMR) vaccine products. The monodispersed mesoporous Fe3O4 nanospheres with self-assembled carboxyl terminated shell have been prepared via a simple solvothermal method. These as-synthesized mesoporous Fe3O4 nanospheres showed a high magnetic saturation value (Ms = 46 emu g-1) and large specific surface area (111.12 m2 g-1) which made them potential candidates as sorbents in magnetic solid-phase extraction. The adsorption experimental data fitted well with the Freundlich-Langmuir isotherm and followed a pseudo-second-order kinetic model. Moreover influential parameters on extraction efficiency were investigated and optimized. Under optimal conditions, the limits of detection for KNM and NEO were 1.0 and 0.1 ng mL-1, respectively. Recovery assessments using real samples exhibited recoveries in the range of 96.0 ± 4.3 to 101.5 ± 7.1 %, with relative standard deviations of <10.7% (for intra- day) and <14.6% (for inter- day). The proposed method was successfully applied for different spiked and un-spiked MMR vaccine samples. The presented extraction method provides a fast, selective, robust and practical platform for the detection of KNM and NEO in MMR vaccine samples.

Design and evaluation of temperature-responsive chitosan/hydroxypropyl cellulose blend nanospheres for sustainable flurbiprofen release.

In present work, temperature-responsive flurbiprofen (FLU) containing chitosan/hydroxypropyl cellulose (CS/HPC) blend nanospheres were prepared using emulsion method. The structures of blend nanospheres were characterized by ATR-FTIR, XRD, SEM, DSC/TGA, zeta potential and particle size analyses. Their lower critical solution temperatures (LCST) were determined and found to be 42 °C. In vitro release studies were performed in gastrointestinal-tract simulated conditions at 30 °C, 37 °C and 44 °C. As the medium temperature was increased, the release of FLU decreased, indicating that blend nanospheres had temperature-responsive feature. The FLU release demonstrated that release profiles depend upon CS/HPC ratio, amount of FLU present in the nanospheres and percentage of cross-linker used. Moreover, the cytotoxicity tests were performed via MTT method and it was observed CS/HPC nanospheres were biocompatible. Based on the in vitro release profile and cytotoxicity studies, the fabricated CS/HPC blend nanospheres could be a promising candidate as a temperature-responsive nano-carrier for controlled drug release.

Electrosprayed Polymeric Nanospheres for Enhanced Solubility, Dissolution Rate, Oral Bioavailability and Antihyperlipidemic Activity of Bezafibrate.

BACKGROUND: Bezafibrate is a BCS class II drug as it presents very low solubility in water; therefore, its bioavailability after oral administration is very poor. The aim of this work was to enhance solubility and dissolution rate of bezafibrate in water in order to enhance its oral bioavailability. METHODS: Several formulations were prepared using PVP K30 and Cremophor ELP employing the solvent-evaporation method and the electrospraying technique. Solubility, release rate, bioavailability in male Sprague Dawley rats, and lipid profile attributes in Wistar rats were assessed in comparison with bezafibrate plain powder. Solid-state characterization was carried out using X-ray diffraction (XRD) analysis, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). RESULTS: All the formulations exerted positive effect towards the desired goal. In particular, the optimized formulation furnished about 14-fold enhanced solubility and 85.48 ± 10.16% drug was released in 10 min as compared with bezafibrate alone (4.06 ± 2.59%). The drug existed in the amorphous state in the prepared sample as confirmed by XRD and DSC, whilst no drug-excipient interactions were observed through FTIR analysis. Moreover, SEM revealed smooth-surfaced spherical particles of the optimized formulation. A 5.5-fold higher oral bioavailability was achieved with the optimized formulation in comparison with bezafibrate plain powder. Also, TG, LDL and TC were decreased, and HDL was increased considerably in HFD-treated rats. CONCLUSION: The optimized formulation consisting of bezafibrate, PVP K30 and cremophor ELP (1/12/1.5, w/w/w) might be a capable drug delivery system for orally administering poorly water-soluble bezafibrate with improved bioavailability and antihyperlipidemic effects.

Label-Free Surface-Enhanced Raman Spectroscopy Biosensor for On-Site Breast Cancer Detection Using Human Tears.

Surface-enhanced Raman scattering (SERS) is an ultrasensitive molecular screening technique with greatly enhanced Raman scattering signals from trace amounts of analytes near plasmonic nanostructures. However, research on the development of a sensor that balances signal enhancement, reproducibility, and uniformity has not yet been proposed for practical applications. In this study, we demonstrate the potential of the practical application for detecting or predicting asymptomatic breast cancer from human tears using a portable Raman spectrometer with an identification algorithm based on multivariate statistics. This potentiality was realized through the fabrication of a plasmonic SERS substrate equipped with a well-aligned, gold-decorated, hexagonal-close-packed polystyrene (Au/HCP-PS) nanosphere monolayer that provided femtomole-scale detection, giga-scale enhancement, and <5% relative standard deviation for reliability and reproducibility, regardless of the measuring site. Our results can provide a first step toward developing a noninvasive, real-time screening technology for detecting asymptomatic tumors and preventing tumor recurrence.

pH and Glutathione Synergistically Triggered Release and Self-Assembly of Au Nanospheres for Tumor Theranostics.

Theranostic agents based on near-infrared absorption which integrate both imaging and therapeutic functions have attracted considerable attention. However, because of the interference signal, indiscriminate treatment usually causes side effects on normal tissues during tumor treatment. To address this limitation, we propose a new synergistically triggered mechanism, release and self-assembly of Au nanospheres, for tumor theranostics based on the synergistic effect of H+ and glutathione on the tumor microenvironment. In vitro experiments reveal that Au nanospheres release from Au@ZIF-8 at a high concentration of H+ or glutathione. Importantly, Au aggregation only appears in the synergistic effect of glutathione and lower pH and exhibits strong coupling plasmonic resonance absorption in the near-infrared region and can be used as the theranostics agent. This statement was further verified by biological transmission electron microscopy and in vivo imaging. Au@ZIF-8 is stable and produces no photoacoustic signal in normal tissue; in contrast, in the presence of overexpressed glutathione and H+, Au nanospheres release from Au@ZIF-8, assemble to aggregates, and exhibit a strong signal at the tumor site for imaging and efficient photothermal therapy. This work provides a new strategy for designing theranostic agents with sequentially responsive steps to avoid interference diagnosis signals from normal tissues and reduce damage to normal tissue during treatment.

Native MicroRNA Targets Trigger Self-Assembly of Nanozyme-Patterned Hollowed Nanocuboids with Optimal Interparticle Gaps for Plasmonic-Activated Cancer Detection.

The modernized use of nucleic acid (NA) sequences to drive nanostructure self-assembly has given rise to a new class of designed nanomaterials with controllable plasmonic functionalities for broad surface-enhanced Raman scattering (SERS)-based bioanalysis applications. Herein, dual usage of microRNAs (miRNAs) as both valuable cancer biomarkers and direct self-assembly triggers is identified and capitalized upon for custom-designed plasmonic nanostructures. Through strict NA hybridization of miRNA targets, Au nanospheres selectively self-assemble onto hollowed Au/Ag alloy nanocuboids with ideal interparticle distances (≈2.3 nm) for optimal SERS signaling. The intrinsic material properties of the self-assembled nanostructures further elevate miRNA detection performance via nanozyme catalytic SERS signaling cascades. This enables fM-level miR-107 detection limit within a clinically-relevant range without any molecular target amplification. The miRNA-triggered nanostructure self-assembly approach is further applied in clinical patient samples, and showcases the potential of miR-107 as a non-invasive prostate cancer diagnostic biomarker. The use of miRNA targets to drive nanostructure self-assembly holds great promise as a practical tool for miRNA detection in disease applications.

Core-shell nanospheres behind the blue eyes of the bay scallop Argopecten irradians.

The bay scallop Argopecten irradians (Mollusca: Bivalvia) has dozens of iridescent blue eyes that focus light using mirror-based optics. Here, we test the hypothesis that these eyes appear blue because of photonic nanostructures that preferentially scatter short-wavelength light. Using transmission electron microscopy, we found that the epithelial cells covering the eyes of A. irradians have three distinct layers: an outer layer of microvilli, a middle layer of random close-packed nanospheres and an inner layer of pigment granules. The nanospheres are approximately 180 nm in diameter and consist of electron-dense cores approximately 140 nm in diameter surrounded by less electron-dense shells 20 nm thick. They are packed at a volume density of approximately 60% and energy-dispersive X-ray spectroscopy indicates that they are not mineralized. Optical modelling revealed that the nanospheres are an ideal size for producing angle-weighted scattering that is bright and blue. A comparative perspective supports our hypothesis: epithelial cells from the black eyes of the sea scallop Placopecten magellanicus have an outer layer of microvilli and an inner layer of pigment granules but lack a layer of nanospheres between them. We speculate that light-scattering nanospheres help to prevent UV wavelengths from damaging the internal structures of the eyes of A. irradians and other blue-eyed scallops.

Surface Engineering of Porous Carbon for Self-Healing Nanocomposite Hydrogels by Mussel-Inspired Chemistry and PET-ATRP.

In this work, surface-functionalized microcapsules from porous carbon nanospheres (PCNs) were successfully prepared by mussel-inspired chemistry with polydopamine (PDA) and metal-free photoinduced electron transfer-atom transfer radical polymerization (PET-ATRP). These functional microcapsules are introduced into self-healing hydrogels to enhance their mechanical strength. The PCNs synthesized by a simple soft template method are mixed with linseed oil for loading of the biomass healing agent, and the microcapsules are first prepared by coating PDA. PDA coatings were used to immobilize the ATRP initiator for initiating 4-vinylpyridine on the surface of microcapsules by PET-ATRP. Using these functional microcapsules, the self-healing efficiency was about 92.5% after 4 h at ambient temperature and the healed tensile strength can be held at 2.5 MPa with a fracture strain of 625.2%. All results indicated that the surface-functionalized microcapsules for self-healing hydrogels have remarkable biocompatibility and mechanical properties.

Three-dimensional assembly of silver nanoparticles spatially confined by cellular structure of Spirulina, from nanospheres to nanosheets.

Three-dimensional (3D) ordered construction of nanoparticles (NPs) has attracted much attention in wide applications, however, techniques with respect to cost effective nanofabrication of well defined functional architectures is still lacking. To address this specific issue, a bio-interface confinement approach is proposed that precisely replicates the complex cellular structural features of microbes and integrates silver NP (SNP) building blocks into their 3D framework in a precise, low cost and mass production way. Herein, the SNPs with nanospheres and nanosheets structure were synthesized by way of electroless deposition using Spirulina as template. Results showed that SNPs were orderly assembled along the cellular structure, and the spatially confinement of cellular texture induced the transformation of SNPs from sphere to flake morphology during their continuous growth. The silver assembly not only shows good antibacterial activity, but also exhibits excellent surface enhanced Raman scattering (SERS) performance with the enhancement factor as high as 5.95 × 108 and good recuperability towards Rhodamine 6G. The fascinating SERS performance can be ascribed to the combined action of nanosheets morphology of SNPs, hierarchical nanostructure of the cellular structure, and the small interparticle spacing. This strategy provides an effective strategy for controllable and ordered 3D assembly of NPs by using the cellular texture.