Phenylboronic acid-modified PEI was prepared by the reaction of 1800 Da PEI with 4-(bromomethyl)phenylboronic acid. It is much more effective than unmodified PEI for gene delivery. The covalently incorporated boronic acid groups achieve the greatly enhanced gene delivery efficiency partially through improving condensation ability to DNA, and partially through facilitating cell uptake due to interaction with ligands in cells.

Gold nanoparticles (GNPs) conjugated with low molecular weight polyethylenimine (PEI 800 Da) were synthesized, and their characteristics as gene transfection vectors were investigated. The polyethylenimine conjugated GNPs (GNP-PEI800s) can retard plasmid DNA completely at N/P ratios above 4 in electrophoresis on agarose gel, and they also render effective protection of DNA from attack by DNase. TEM imaging revealed that GNP-PEI800s with higher PEI grafting density resulted in more compact and smaller complexes with plasmid DNA, compared to those obtained with lower grafting density ones. These complexes showed high efficiency in gene delivery in monkey kidney cells in vitro. In the absence of serum, GNP-PEI800s can transfect pGL-3 to COS-7 cells 3 to 4 orders more efficient than unmodified PEI800, reaching almost the same magnitude of PEI 25 kDa. More importantly, in contrast to the dramatically lowered efficiency of high molecular weight PEIs such as PEI 25 kDa in the presence of serum, the efficiency of GNP-PEI800s can be retained or even enhanced in serum-containing media. GNP-PEI800 1.3 exhibited transfection efficiency exceeding 60-fold that of PEI 25 kDa in 10% serum medium. All GNP-PEI800s exhibit mild cytotoxicity in comparison with that of PEI 25 kDa.

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Highly ordered mesoporous crystalline Mo-doped WO2 (Mo x W1–x O2: 1 > x > 0.08) materials with different molybdenum contents were synthesized via a nanocasting strategy using mesoporous silica KIT-6 as a hard template. The presence of molybdenum significantly increased the rate of reduction of tungsten trioxide to tungsten dioxide using hydrogen gas as the reducing agent, and it also prevented the dioxide product from being further reduced to zerovalent metal tungsten. This molybdenum doping strategy provides a new solution for the synthesis of WO2-based materials with well-defined nanostructures. The obtained mesoporous Mo0.14W0.86O2 material possessed a metallic conductivity (0.8 Ω cm, 300 K) and a high tap density of 3.6 g cm–3. This material exhibits a high and reversible lithium storage capacity of 635 mAh g–1 and is stable up to at least 70 cycles without noticeable fading.

Well-defined amphiphilic block-graft copolymers PCL-b-[DTC-co-(MTC-mPEG)] with polyethylene glycol methyl ether pendant chains were designed and synthesized. First, monohydroxyl-terminated macroinitiators PCL-OH were prepared. Then, ring-opening copolymerization of 2,2-dimethyltrimethylene carbonate (DTC) and cyclic carbonate-terminated PEG (MTC-mPEG) macromonomer was carried out in the presence of the macroinitiator in bulk to give the target copolymers. All the polymers were characterized by (1) H NMR and gel permeation chromatography (GPC). The polymers have unimodal molecular weight distributions and moderate polydispersity indexes. The amphiphilic block-graft copolymers self-assemble in water forming stable micelle solutions with a narrow size distribution.