Xinglong Yang

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.

D-alanyl-D-alanine-Modified Gold Nanoparticles Form a Broad-Spectrum Sensor for Bacteria

Rationale: Rapid and facile detection of pathogenic bacteria is challenging due to the requirement of large-scale instruments and equipment in conventional methods. We utilize D-amino acid as molecules to selectively target bacteria because bacteria can incorporate DADA in its cell wall while mammalian cells or fungi cannot. Methods: We show a broad-spectrum bacterial detection system based on D-amino acid-capped gold nanoparticles (AuNPs). AuNPs serve as the signal output that we can monitor without relying on any complex instruments. Results: In the presence of bacteria, the AuNPs aggregate and the color of AuNPs changes from red to blue. This convenient color change can distinguish between Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA). This system can be applied for detection of ascites samples from patients. Conclusion: These D-amino acid-modified AuNPs serve as a promising platform for rapid visual identification of pathogens in the clinic.

Small Molecular TGF-β1-Inhibitor-Loaded Electrospun Fibrous Scaffolds for Preventing Hypertrophic Scars

Hypertrophic scarring (HS) is a disorder that occurs during wound healing and seriously depresses the quality of human life. Scar-inhibiting scaffolds, though bringing promise to HS prevention, face problems such as the incompatibility of the scaffold materials and the instability of bioactive molecules. Herein, we present a TGF-β1-inhibitor-doped poly(ε-caprolactone) (PCL)/gelatin (PG) coelectrospun nanofibrous scaffold (PGT) for HS prevention during wound healing. The appropriate ratio of PCL to gelatin can avoid individual defects of the two materials and achieve an optimized mechanical property and biocompatibility. The TGF-β1 inhibitor (SB-525334) is a small molecule and is highly stable during electrospinning and drug release processes. The PGT effectively inhibits fibroblast (the major cell type contributing to scar formation) proliferation in vitro and successfully prevents HS formation during the healing of full-thickness model wounds on rabbit ear. Our strategy offers an excellent solution for potential large-scale production of scaffolds for clinical HS prevention.

Aminosaccharide–gold nanoparticle assemblies as narrow-spectrum antibiotics against methicillin-resistant Staphylococcus aureus

Bacterial infection has continued to be a leading cause of death or disability worldwide because of antibiotic resistance. Antibiotic agents specific to certain taxa of bacteria, i.e., narrow-spectrum antibiotics, have become useful because they can kill bacteria without resulting in broad-spectrum drug resistance. In this study, we describe a series of antibiotics based on combining gold nanoparticles (AuNPs) with aminosaccharides, even though these AuNPs or aminosaccharides by themselves are ineffective against any bacteria. The AuNP-based multivalent aminosaccharides can effectively and selectively inhibit the growth of Gram-positive bacteria (including drug-resistant superbacteria). In particular, aminosaccharide-modified AuNPs are effective against methicillin-resistant Staphylococcus aureus (MRSA), a particularly hard-to-treat strain. This report carves out a way to explore antibiotics by combining AuNPs and an aminosaccharide as multivalent nanostructures, neither of which by itself is effective as an antibiotic.