Enhanced heterogeneous interface to construct intelligent conductive hydrogel gas sensor for individualized treatment of infected wounds.

In this study, we developed an enhanced heterogeneous interface intelligent conductive hydrogel NH3 sensor for individualized treatment of infected wounds. The sensor achieved monitoring, self-diagnosis, and adaptive gear adjustment functions. The PPY@PDA/PANI(3/6) sensor had a minimum NH3 detection concentration of 50 ppb and a response value of 2.94 %. It also had a theoretical detection limit of 49 ppt for infected wound gas. The sensor exhibited a fast response time of 23.2 s and a recovery time of 42.9 s. Tobramycin (TOB) was encapsulated in a self-healing QCS/OD hydrogel formed by quaternized chitosan (QCS) and oxidized dextran (OD), followed by the addition of polydopamine-coated polypyrrole nanowires (PPY@PDA) and polyaniline (PANI) to prepare electrically conductive drug-loaded PPY@PDA/PANI hydrogels. The drug-loaded PPY@PDA/PANI hydrogel was combined with a PANI/PVDF membrane to form an enhanced heterogeneous interfacial PPY@PDA/PANI/PVDF-based sensor, which could adaptively learn the individual wound ammonia response and adjust the speed of drug release from the PPY@PDA/PANI hydrogel with electrical stimulation. Drug release and animal studies demonstrated the efficacy of the PPY@PDA/PANI hydrogel in inhibiting infection and accelerating wound healing. In conclusion, the gas-sensitive conductive hydrogel sensing system is expected to enable intelligent drug delivery and provide personalized treatment for complex wound management.

Facile formation of folic acid-modified dendrimer-stabilized gold-silver alloy nanoparticles for potential cellular computed tomography imaging applications.

We report a facile approach to fabricating dendrimer-stabilized gold-silver alloy nanoparticles (Au-Ag alloy DSNPs) for targeted in vitro computed tomography (CT) imaging of cancer cells. In this study, folic acid (FA)-modified amine-terminated generation 5 poly(amidoamine) dendrimers (G5·NH2-FA) were used as stabilizers to prepare Au-Ag alloy DSNPs by simultaneously reducing both gold and silver salts, followed by acetylation of the dendrimer terminal amines. The formed Au-Ag alloy DSNPs were characterized via different techniques. We show that the formed Au-Ag alloy DSNPs are spherical in shape with a relatively narrow size distribution, have good water solubility and colloidal stability, and display higher X-ray attenuation intensity than the iodine-based contrast agent of Omnipaque at the same molar concentration of the active element (i.e., Au plus Ag, or iodine). Cytotoxicity assay results show that the Au-Ag alloy DSNPs are cytocompatible in a given concentration range. Importantly, the formed Au-Ag alloy DSNPs are able to be specifically taken up by cancer cells overexpressing FA receptors and enable targeted CT imaging of the cancer cells. Given the unique structural characteristics of dendrimers and the facile synthesis of DSNPs, the developed Au-Ag alloy DSNPs may be used for various biomedical applications in sensing, diagnosis, and therapeutics.

PEGylation of black kidney bean (Phaseolus vulgaris L.) protein isolate with potential functironal properties.

In this work, we investigated PEGylated black kidney bean protein isolates (BKBPI) by PEG succinimidyl carbonate (PEG-SC), PEG succinimidyl succinate (PEG-SS) and PEG succinimidyl propionate (PEG-SPA) conjugation. The functional properties, thermodynamic stability, in vitro digestion stability, and hemagglutination activity of the modified products were evaluated. The degree of PEGylation was measured, and FTIR analysis revealed that protein-PEG conjugations were formed, and that no obvious changes in water- and fat-holding capacities were observed. The solubility, emulsifying property, and foaming property were all improved through the modification, while, higher thermodynamic stability was achieved with the increase in Td values and reduction of ΔH. The PEGylated proteins were found to be more resistant to in vitro digestion, and the hemagglutination activity was significantly (P < 0.05) decreased, indicating the higher safety of the protein isolate. The results showed that the functional properties, thermodynamic stability, and biological safety of BKBPI were improved by PEGylation, which could serve to increase the applications for this protein.

Synthesis of PEGylated low generation dendrimer-entrapped gold nanoparticles for CT imaging applications.

Dendrimer-entrapped gold nanoparticles (Au DENPs) can be formed using low-generation dendrimers pre-modified by polyethylene glycol (PEG). The formed PEGylated Au DENPs with desirable stability, cytocompatibility, and X-ray attenuation properties enable efficient computed tomography imaging of the heart and tumor model of mice.

Tunable synthesis and acetylation of dendrimer-entrapped or dendrimer-stabilized gold-silver alloy nanoparticles.

In this study, amine-terminated generation 5 poly(amidoamine) dendrimers were used as templates or stabilizers to synthesize dendrimer-entrapped or dendrimer-stabilized Au-Ag alloy nanoparticles (NPs) with different gold atom/silver atom/dendrimer molar ratios with the assistance of sodium borohydride reduction chemistry. Following a one-step acetylation reaction to transform the dendrimer terminal amines to acetyl groups, a series of dendrimer-entrapped or dendrimer-stabilized Au-Ag alloy NPs with terminal acetyl groups were formed. The formed Au-Ag alloy NPs before and after acetylation reaction were characterized using different techniques. We showed that the optical property and the size of the bimetallic NPs were greatly affected by the metal composition. At the constant total metal atom/dendrimer molar ratio, the size of the alloy NPs decreased with the gold content. The formed Au-Ag alloy NPs were stable at different pH (pH 5-8) and temperature (4-50°C) conditions. X-ray absorption coefficient measurements showed that the attenuation of the binary NPs was dependent on both the gold content and the surface modification. With the increase of gold content in the binary NPs, their X-ray attenuation intensity was significantly enhanced. At a given metal composition, the X-ray attenuation intensity of the binary NPs was enhanced after acetylation. Cytotoxicity assays showed that after acetylation, the cytocompatibility of Au-Ag alloy NPs was significantly improved. With the controllable particle size and optical property, metal composition-dependent X-ray attenuation characteristics, and improved cytocompatibility after acetylation, these dendrimer-entrapped or dendrimer-stabilized Au-Ag alloy NPs should have a promising potential for CT imaging and other biomedical applications.