FADH2-mediated radical polymerization amplification for microRNA-21 detection

For early diagnosis of disease, ultrasensitive mircoRNA-21 detection has considerable potential. In this paper, an ultra-sensitive fluorescence detection method for microRNA was developed by atom transfer radical polymerization (ATRP). This ATRP reaction was first initiated by using flavin mononucleotide (FADH2). The DNA probe 1 modified with amino group was fixed on the magnetic nanoparticle Fe3O4, and microRNA-21 was added to form the probe 1-microRNA-21. Another carboxy-modified DNA 2 forms a sandwich structure with the bound microRNA-21. Two terminally modified DNA types are used as microRNA probes, using complementary base pairing to form a stable super-sandwich structure between the DNA probe and the microRNA. Under optimal conditions, microRNA was detected in PBS buffer with a detection limit of 0.19 fM. And even in 10% of human serum, microRNA-21 can be detected with a detection limit of 47.8 fM. Results show that this method has high selectivity, efficiency and stability, which broad application prospect in microRNA ultra-sensitive detection.

Dual-Drug Conjugated Glyco-Nanoassemblies for Tumor-Triggered Targeting and Synergistic Cancer Therapy

Drug-conjugated nanoassemblies potentiate the efficiency of anticancer drugs through the advantages of high drug-loading capacity and passive/active targeting ability in cancer therapy. This study describes the synthesis of gemcitabine (Gem) and cisplatin (cisPt) dual-drug-functionalized glyco-nanoassemblies (GNs) for anticancer drug delivery systems. It also investigates the pH-triggered drug delivery of the conventional anticancer drug cisPt. A Gem-functionalized well-defined glycoblock copolymer backbone (P(iprFruMA-b-MAc)-Gem), which consists of fructose and methacrylic acid segments, was synthesized via a reversible addition-fragmentation chain transfer (RAFT) polymerization method. Following the hydrolysis of the protecting groups on the backbone copolymer, cisPt functionalization of P(FruMA-b-MAc)-Gem in aqueous media was carried out during the transformation of glycoblock polymers into self-assembled spherical glyco-nanoassemblies (GN3). Monodrug-functionalized glyco-nanoassemblies were also prepared either with Gem (GN1) or cisPt (GN2) to compare the synergetic effect of dual-drug conjugated glyco-nanoassemblies (GN3). The sizes of glyco-nanoassemblies GN1, GN2, and GN3 were found as 5.76 ± 0.64, 59.80 ± 0.13, and 53.80 ± 3.90 nm and dispersity (Đ) values as 0.476, 0.292, and 0.311 by dynamic light scattering (DLS) measurement, respectively. The in vitro studies revealed that the drug-free glyco-nanoassemblies are biocompatible at concentrations higher than 296 μg/mL. The drug-conjugated glyco-nanoassemblies (GN1 and GN2) exhibited in vitro cytotoxicity against human breast cancer cell lines of MDA-MB-231 comparable to free Gem and cisPt, illustrating an efficient drug release into the tumor environment. Additionally, GNs exhibited higher selectivity and preferential cellular internalization in MDA-MB-231 when compared to healthy cell lines of CCD-1079Sk. These dual-drug conjugated GNs can effectively enhance the killing of cancer cells and increase synergistic chemotherapy.

Alcohol-Soluble Cross-Linked Poly( nBA) n- b-Poly(NVTri) m Block Copolymer and Its Applications in Organic Photovoltaic Cells for Improved Stability

In this study, a series of alcohol-soluble cross-linked block copolymers (BCPs) consisting of poly( n-butyl acrylate) (poly( nBA)) and poly( N-vinyl-1,2,4-triazole) (poly(NVTri)) blocks with different individual functions and lengths are designed and developed. These presynthesized cross-linked BCPs (PBA _n-Tri _m) were, for the first time, revealed to exhibit many advantages in serving as the electron-extraction layer (EEL) for organic photovoltaics (OPVs). The cross-linked BCPs possessed intense ionic functionality, showing well capability to form effective interfacial dipoles at the indium tin oxide interface to facilitate the charge extraction at the corresponding interface. Furthermore, it also consisted a core-shell structure, wherein the polar poly(NVTri) core was well protected by the poly( nBA) shell to endow improved robustness against solvent erosion and thermal/photo inputs. Consequently, the PBA₇₀-Tri₃₀ device yielded a decent power conversion efficiency of 8.03% with a V_oc of 0.83 V, much exceeding the performance of the control device without using any EEL. Moreover, this device showed superior thermal stability/photostability. More than 80% of its initial performance was retained after being heated at 60 °C for 1000 h or exposed under continuous illumination (1 sun) for 1000 h, greatly surpassing the lifetime of the control device and the reference device using a common poly[(9,9-bis(3'-( N, N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) EEL. The results revealed the merit of using cross-linked BCPs in improving the long-term stability of OPVs.

Entry of nanoparticles into cells: the importance of nanoparticle properties

Knowledge of the interactions between nanoparticles (NPs) and cell membranes is of great importance for the design of safe and efficient nanomedicines.

The effect of linker length on ConA and DC-SIGN binding of S-glucosyl functionalized poly(2-oxazoline)s

A series of poly(2-oxazoline) based glycopolymers with different linkers were prepared via thiol–ene click reaction and cationic ring opening reaction. The binding of these polymers to lectins were studied.

Influence of nanoparticle shapes on cellular uptake of paclitaxel loaded nanoparticles in 2D and 3D cancer models

Enhanced cellular uptake and efficient penetration of nanocarriers inside tumors is paramount to successful anti-cancer therapy.

Size effect of SnO2 nanoparticles on bacteria toxicity and their membrane damage

Semiconductor SnO₂ nanoparticles (NPs) are being exploited for various applications, including those in the environmental context. However, toxicity studies of SnO₂ NPs are very limited. This study evaluated the toxic effect of two sizes of spherical SnO₂ NPs (2 and 40 nm) and one size of flower-like SnO₂ NPs (800 nm) towards the environmental bacteria E. coli and B. subtilis. SnO₂ NPs were synthesized using a hydrothermal or calcination method and they were well characterized prior to toxicity assessment. To evaluate toxicity, cell viability and membrane damage were determined in cells (1 × 10⁹ CFU mL^-1) exposed to up to 1000 mg L^-1 of NPs, using the plate counting method and confocal laser scanning microscopy. Spherical NPs of smaller primary size (E2) had the lowest hydrodynamic size (226 ± 96 nm) and highest negative charge (-30.3 ± 10.1 mV). Smaller spherical NPs also showed greatest effect on viability (IC₅₀ > 500 mg L^-1) and membrane damage of B. subtilis, whereas E. coli was unaffected. Scanning electron microscopy confirmed the membrane damage of exposed B. subtilis and also exhibited the attachment of E2 NPs to the cell surface, as well as the elongation of cells. It was also apparent that toxicity was caused solely by NPs, as released Sn⁴⁺ was not toxic to B. subtilis. Thus, surface charge interaction between negatively charged SnO₂ NPs and positively charged molecules on the membrane of the Gram positive B. subtilis was indicated as the key mechanism related to toxicity of NPs.

Shape Effect of Glyco-Nanoparticles on Macrophage Cellular Uptake and Immune Response

The shells of various poly(dl-lactide)-b-poly(acrylic acid) (PDLLA-b-PAA) spherical micelles and poly(l-lactide)-b-poly(acrylic acid) (PLLA-b-PAA) cylindrical micelles were functionalized with mannose to yield glyco-nanoparticles (GNPs) with different shapes and dimensions. All of these GNPs were shown to have good biocompatibility (up to 1 mg/mL). Cellular uptake experiments using RAW 264.7 have shown that the spherical GNPs were internalized to a much greater extent than the cylindrical GNPs and such a phenomenon was attributed to their different endocytosis pathways. It was demonstrated that spherical GNPs were internalized based on clathrin- and caveolin-mediated endocytosis while cylindrical GNPs mainly depended on clathrin-mediated endocytosis. We also found that longer cylindrical GNPs (Ln × Wn = 215 × 47 nm) can induce an inflammatory response (specifically interleukin 6) more efficiently than shorter cylindrical GNPs (Ln × Wn = 99 × 50 nm) and spherical GNPs (Dn = 46 nm).

Tunable Nanocarrier Morphologies from Glycopolypeptide-Based Amphiphilic Biocompatible Star Copolymers and Their Carbohydrate Specific Intracellular Delivery

Nanocarriers with carbohydrates on the surface represent a very interesting class of drug-delivery vehicles because carbohydrates are involved in biomolecular recognition events in vivo. We have synthesized biocompatible miktoarm star copolymers comprising glycopolypeptide and poly(ε-caprolactone) chains using ring-opening polymerization and "click chemistry". The amphiphilic copolymers were self-assembled in water into morphologies such as nanorods, polymersomes, and micelles with carbohydrates displayed on the surface. We demonstrate that the formation of nanostructure could be tuned by chain length of the blocks and was not affected by the type of sugar residue. These nanostructures were characterized in detail using a variety of techniques such as TEM, AFM, cryogenic electron microscopy, spectrally resolved fluorescence imaging, and dye encapsulation techniques. We show that it is possible to sequester both hydrophobic as well as hydrophilic dyes within the nanostructures. Finally, we show that these noncytotoxic mannosylated rods and polymersomes were selectively and efficiently taken up by MDA-MB-231 breast cancer cells, demonstrating their potential as nanocarriers for drug delivery.

Design, synthesis and thermotropic self-organization of dendronized polystyrenes with different length alkyl tails

A reentrant phase is observed for the first time in dendronized polystyrenes with high molecular weight through regulating the length of tail chains.