Poly(l-ornithine)-Grafted Zinc Phthalocyanines as Dual-Functional Antimicrobial Agents with Intrinsic Membrane Damage and Photothermal Ablation Capacity.

Multifunctional antimicrobial peptides that combine the intrinsic microbicidal property of cationic polypeptide chains and additional antibacterial strategy hold promising applications for the treatment of infections caused by antibiotic-resistant bacteria, especially "superbugs". In the present study, star-shaped copolymers ZnPc-g-PLO with a zinc phthalocyanine (ZnPc) core and four poly(l-ornithine) (PLO) arms were designed, synthesized, and evaluated as dual-functional antimicrobial agents, that is, intrinsic membrane damage and photothermal ablation capacity. In an aqueous solution, amphiphilic ZnPc-g-PLO molecules self-assemble into nanosized polymeric micelles with an aggregated ZnPc core and star-shaped PLO periphery, where the ZnPc core exhibits appreciable aggregation-induced photothermal conversion efficiency. In the absence of laser irradiation, ZnPc-g-PLO micelles display potent and broad-spectrum antibacterial activities via physical bacterial membrane disruption as a result of the high cationic charge density of the star-shaped PLO. Upon laser irradiation, significant improvement in bactericidal potency was realized due to the efficacious photothermal sterilization from the ZnPc core. Notably, ZnPc-g-PLO micelles did not induce drug-resistance upon subinhibitory passages. In summary, dual-functional ZnPc-g-PLO copolymers can serve as promising antibacterial agents for the treatment of infectious diseases caused by antibiotic-resistant bacteria.

Poly(α-l-lysine)-based nanomaterials for versatile biomedical applications: Current advances and perspectives.

Poly(α-l-lysine) (PLL) is a class of water-soluble, cationic biopolymer composed of α-l-lysine structural units. The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites. PLL-based polymers and copolymers, till date, have been extensively explored in the contexts such as antibacterial agents, gene/drug/protein delivery systems, bio-sensing, bio-imaging, and tissue engineering. This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade. The review first describes the synthesis of PLL and its derivatives, followed by the main text of their recent biomedical applications and translational studies. Finally, the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.

High-speed mass measurement of nanoparticle and virus.

Until now, there have been no relatively easy methods to measure the mass and mass distributions of nanoparticles/viruses. In this work, we report the first set of measurements of mass and mass distributions for nanoparticles/viruses using a novel mass spectrometry technology. In the past, mass spectrometry was typically used to measure the mass of a particle or molecule with a mass less than 1,000,000 Da. We developed cell mass spectrometry that can measure the mass of a cell or a microparticle. Nevertheless, there is a gap for mass measurement methods in the mass region of a nanoparticle or virus (1 MDa to 1 GDa). Here, we developed a nanoparticle/virus mass spectrometry technique to make rapid and accurate mass and mass distribution measurements of nanoparticles/viruses. This technique should be valuable for the quality control of nanoparticle production and the identification of various viruses. In the future, this method can also serve to monitor drug delivery when nanoparticles are used as carriers. Furthermore, it may be possible to measure the degree of infection by measuring the number of viruses in specific cells or in plasma.

Charge monitoring cell mass spectrometry.

An instrument to directly measure the charge carried by a cell or a microparticle as well as mass-to-charge ratio of the cell/microparticle was developed for rapid mass distribution measurement. A successful mass spectrum with a record high mass has been demonstrated. In this article, the details of the construction and operation of the charge monitoring cell mass spectrometer are reported. Examples are also given for demonstration and discussion.

High-speed mass analysis of whole erythrocytes by charge-detection quadrupole ion trap mass spectrometry.

Herein, we report an application of charge-detection quadrupole ion trap mass spectrometry to the measurement of total dry masses of mammalian and poultry erythrocytes evaporated/ionized by laser-induced acoustic desorption. The method is rapid and widely applicable. Eight different types of red blood cells (RBCs) have been successfully analyzed, including those of human, goat, cow, mouse, pig, and chicken. The measured mean masses (weights per corpuscle) range from 0.58 x 10(13) Da (9.6 pg) of goat RBCs to 2.80 x 10(13) Da (46.5 pg) of chicken RBCs. The total dry weights determined for human RBCs from a healthy male adult, a patient with iron-deficiency anemia, and a patient with thalassemia are 34.8, 28.8, and 20.6 pg, respectively. These weights, except that of thalassemia, are all approximately 10% higher than their corresponding mean corpuscular hemoglobin values determined by a commercial automated hematology analyzer. The mass distribution profiles of the cells are all near-Gaussian, with a standard deviation of 15% for the normal human RBCs. The deviation increases significantly to 20% for RBCs with thalassemia characteristics and 27% for RBCs with iron-deficiency anemia characteristics. All the observations are in accord with their corresponding mean corpuscular volume measurements, indicating an increase in anisocytosis (variation in RBC size) in the anemic samples. Our results suggest a broad and promising application of this new technology to high-speed mass analysis of RBCs and other biological whole cells as well.

New highly nucleophilic and practically accessible chlorocarbenoids for carbonyl olefination.

[reaction: see text] Direct oxidative addition of CHCl3 to the Mg-TiCl4 bimetallic species resulted in the generation of a highly nucleophilic and practically convenient chloromethylenetitanium complex, which efficiently effected condensation even with enolizable or inert carbonyl compounds, such as sterically congested ketones, to provide vinyl chloride compounds.

Formation of tannin-albumin nano-particles at neutral pH as measured by light scattering techniques.

Aggregation phenomena of tannin with bovine serum albumin were investigated by light scattering techniques including photon correlation spectroscopy and Rayleigh scattering. Tannin and albumin formed particles with diameters less than 1 microm at neutral pH. As revealed by this study, light scattering methods are useful in investigating aggregation phenomena of biomolecules and in directly quantifying tannin content.