Convergent Synthesis of the Precursors to Thiophene-Based Quinoids.

A convergent (outside-to-center) route was adopted to synthesize the precursors of quinoidal compounds in high yields of 85-93%. With subsequent rearrangement/dehydroxylation and oxidation, a series of thiophene-based quinoids with indandione or oxindole terminal groups were successfully synthesized. This strategy shows good compatibility with versatile central and terminal units, leading to quinoidal compounds with tunable properties.

Study on swelling and drug releasing behaviors of ibuprofen-loaded bimetallic alginate aerogel beads with pH-responsive performance.

Bimetallic alginate aerogel beads were prepared by ionotropic gelation method with Ca2+-Ba2+ bimetallic solution and ibuprofen was loaded as a model drug. The swelling and drug releasing behaviors of the beads, especially the influence of barium, were investigated in artificial gastric and intestinal fluids. The results showed that these beads presented higher encapsulation efficiency due to the special structure of aerogel, and barium was beneficial for the more stable structure and drug releasing behavior. The lower swelling capacity of bimetallic beads was observed than monometallic beads. A rapid high-level releasing of ibuprofen was achieved in artificial intestinal fluid, which was up to 96.9% within 1 h, while ibuprofen releasing was avoided in artificial gastric fluid effectively. The drug releasing mechanism of these beads was explored in detail. In the bimetallic crosslinking system, Ba2+ presented a special effect on alginate beads with more sensitive pH response performance. Thus, these beads had more widely potential as a site-specific delivery system, especially for intestinal therapy.

Chaperone Copolymer-Assisted Aptamer-Patterned DNA Hydrogels for Triggering Spatiotemporal Release of Protein.

In this paper, a DNA hydrogel with low DNA concentration, short sticky end, and good mechanical strength was simply prepared via one-pot self-assembly from two kinds of DNA building block (X- and L-shaped DNA units) chaperoned by a cationic comb-type copolymer (CCC). The gelling process was completed under physiological conditions within 1 min, and the reversible sol-gel phase transition was achieved at room temperature through the continuous addition of CCC and an anionic polymer poly(sodium vinylsulfonate). Moreover, aptamer was successfully patterned into the hydrogel system via click chemistry. Upon the addition of complementary sequences (CSs) of aptamer, the aptamer was hybridized with CSs, leading to the fast dissociation of protein from aptamer with an adjustable release rate in specific regions at prospective times. The hydrogel with excellent cytocompatibility was successfully applied to human serum, a complex matrix. The aptamer-patterned DNA hydrogel is a potential candidate for controlled protein delivery.