Huawu Shao

Using Azobenzene‐Embedded Self‐Assembled Monolayers To Photochemically Control Cell Adhesion Reversibly

A celling point: A mixed self-assembled monolayer comprising two types of alkanethiols--one containing an azobenzene unit terminated with a peptide, the other containing a hexa(ethylene glycol) group that resists nonspecific cell adhesion--enables cell adhesion to be modulated photochemically. The reversible conversion of the azobenzene moiety between E and Z configurations allows the surface to either support or resist cell adhesion.

Colorimetric detection of mercury, lead and copper ions simultaneously using protein-functionalized gold nanoparticles.

A simple, cost-effective and rapid colorimetric method for any or all of Hg(2+), Pb(2+) and Cu(2+) detection using papain-functionalized gold nanoparticles (P-AuNPs) has been developed. Papain is a protein with seven cystein residues, which can selectively bind with Hg(2+), Pb(2+) and Cu(2+). We functionalized gold nanoparticles with papain. The P-AuNPs could be used to simultaneously detect Hg(2+), Pb(2+) and Cu(2+), and showed different responses to the three ions in an aqueous solution based on the aggregation-induced color change of gold nanoparticles. The P-AuNPs displayed the most obvious response to mercury ions in water in contrast to lead and copper ions, and the real water sample analysis verified the conclusion. The sensitivity of the detection system was influenced by the pH of the P-AuNPs solution, the concentration of P-AuNPs and the size of gold nanoparticles, and we found that larger gold nanoparticles contributed to more sensitive results. The detection system can detect as low as 200 nM Hg(2+), Pb(2+) or Cu(2+) using 42 nm gold nanoparticles. We expect our approach to have wide-ranging applications in the developing region for monitoring water quality in some areas.

Label-Free Colorimetric Detection of Cadmium Ions in Rice Samples Using Gold Nanoparticles

A simple and label-free colorimetric method for cadmium ions (Cd(2+)) detection using unmodified gold nanoparticles (AuNPs) is reported. The unmodified AuNPs easily aggregate in a high concentration of NaCl solution, but the presence of glutathione (GSH) can prevent the salt-induced aggregation of AuNPs. When Cd(2+) is added to the stable mixture of AuNPs, GSH, and NaCl, Cd(2+) can coordinate with 4× GSH as a spherical shaped complex, which decreases the amount of free GSH on the surface of gold nanoparticles to weaken the stability of AuNPs, and AuNPs will easily aggregate in high-salt conditions. On the basis of the mechanism, we design a simple, label-free colorimetric method using AuNPs accompanied by GSH in a high-salt environment to detect Cd(2+) in water and digested rice samples.

One-pot three-component Mannich-type reactions using Sulfamic acid catalyst under ultrasound irradiation

Sulfamic acid (NH(2)SO(3)H, SA) was used as an efficient, inexpensive, non-toxic and recyclable green catalyst for the ultrasound-assisted one-pot Mannich reaction of aldehydes with ketones and amines. This ultrasound protocol has advantages of high yield, mild condition, no environmental pollution, and simple work-up procedures. Most importantly, beta-aminocarbonyl compounds with ortho-substituted aromatic amines are obtained in acceptable to good yields by this methodology for the first time.

Pharmaceutical Intermediate-Modified Gold Nanoparticles: Against Multidrug-Resistant Bacteria and Wound-Healing Application via an Electrospun Scaffold

Remedying a multidrug-resistant (MDR) bacteria wound infection is a major challenge due to the inability of conventional antibiotics to treat such infections against MDR bacteria. Thus, developing wound dressings for wound care, particularly against MDR bacteria, is in huge demand. Here, we present a strategy in designing wound dressings: we use a small molecule (6-aminopenicillanic acid, APA)-coated gold nanoparticles (AuNPs) to inhibit MDR bacteria. We dope the AuNPs into electrospun fibers of poly(ε-caprolactone) (PCL)/gelatin to yield materials that guard against wound infection by MDR bacteria. We systematically evaluate the bactericidal activity of the AuNPs and wound-healing capability via the electrospun scaffold. APA-modified AuNPs (Au_APA) exhibit remarkable antibacterial activity even when confronted with MDR bacteria. Meanwhile, Au_APA has outstanding biocompatibility. Moreover, an in vivo bacteria-infected wound-healing experiment indicates that it has a striking ability to remedy a MDR bacteria wound infection. This wound scaffold can assist the wound care for bacterial infections.

InCl3 Catalyzed Highly Diastereoselective [3+2] Cycloaddition of 1,2-Cyclopropanated Sugars with Aldehydes: A Straightforward Synthesis of Persubstituted Bis-Tetrahydrofurans and Perhydrofuro[2,3-b]pyrans

A mild and efficient strategy for the construction of persubstituted bis-tetrahydrofuran and perhydrofuro[2,3-b]pyran derivatives has been developed. Persubstituted cyclization products were obtained in good to excellent yields. The [3 + 2] cycloaddition of 1,2-cyclopropanated sugars with aldehydes in the presence of InCl3 is highly diastereoselective.

An efficient synthesis of 3-substituted indole derivates under ultrasound irradiation

A solvent-free procedure for the synthesis of 3-substituted indole derivates from indoles and nitroalkenes under ultrasound irradiation is described. Control experiments disclosed besides mechanical effects, namely agitation, sonochemical effects are the main forces to drive the reaction. In the method, 2-chloroethanol was used to prepare a wide variety of 3-substituted indole derivates. This procedure only need equimolar amounts of reaction substrates and can be readily scaled up.

A simple and convenient method for the synthesis of pyranoid glycals

A simple, mild, and environmentally benign synthesis procedure of pyranoid glycals is described. In a novel fashion, protected glycopyranosyl bromides undergo the reductive elimination in the presence of zinc in phosphate buffer at room temperature. The pyranoid glycals were obtained in good-to-excellent yields (18 examples).

Stereoselective synthesis of 2-C-acetonyl-2-deoxy-D-galactosides using 1,2-cyclopropaneacetylated sugar as novel glycosyl donor.

1,2-Cyclopropaneacetylated sugar is an effective glycosyl donor, which reacted with various glycosyl acceptors including monosaccharides, amino acids and other alcohols in the presence of BF(3)*OEt(2) or TMSOTf. The glycosylation is stereoselective in favor of beta-anomeric products with BF(3)*OEt(2) as catalyst, whereas TMSOTf-catalyzed glycosylation prefers the alpha-anomeric products. 2-C-Acetonyl-2-deoxy-D-galactosides were obtained in good yields.

Lathyrol Diterpenes as Modulators of P-Glycoprotein Dependent Multidrug Resistance: Structure–Activity Relationship Studies on Euphorbia Factor L3 Derivatives

Five series of 37 new acylate and epoxide derivatives (3-39) of Euphorbia factor L3, a lathyrol diterpene isolated from Euphorbia lathyris, were designed by modifying the hydroxyl moiety of C-3, C-5, or C-15. Chemoreversal effects of the acylates on multidrug resistance (MDR) were evaluated in breast cancer multidrug-resistant MCF-7/ADR cells that overexpress P-glycoprotein (P-gp). Eight derivatives exhibited greater chemoreversal ability than verapamil (VRP) against adriamycin (ADR) resistance. Compounds 19 and 25 exhibited 4.8 and 4.0 times, respectively, more effective reversal ability than VRP against ADR resistance. To determine the key characteristics of Euphorbia factor L3 derivatives that contribute to MDR reversal, we conducted a structure-activity relationship study of these compounds. The simulation studies indicated different possible mechanisms and revealed the important influence of hydrophobic interactions and hydrogen bonds in the flexible cavity of P-gp.