Antimicrobial properties of chitosan and mode of action: A state of the art review

Antimicrobial nanomaterials for water disinfection and microbial control: Potential applications and implications

Strain specificity in antimicrobial activity of silver and copper nanoparticles

In medicine, nanotechnology has sparked a rapidly growing interest as it promises to solve a number of issues associated with conventional therapeutic agents, including their poor water solubility (at least, for most anticancer drugs), lack of targeting capability, nonspecific distribution, systemic toxicity, and low therapeutic index. Over the past several decades, remarkable progress has been made in the development and application of engineered nanoparticles to treat cancer more effectively. For example, therapeutic agents have been integrated with nanoparticles engineered with optimal sizes, shapes, and surface properties to increase their solubility, prolong their circulation half-life, improve their biodistribution, and reduce their immunogenicity. Nanoparticles and their payloads have also been favorably delivered into tumors by taking advantage of the pathophysiological conditions, such as the enhanced permeability and retention effect, and the spatial variations in the pH value. Additionally, targeting ligands (e.g., small organic molecules, peptides, antibodies, and nucleic acids) have been added to the surface of nanoparticles to specifically target cancerous cells through selective binding to the receptors overexpressed on their surface. Furthermore, it has been demonstrated that multiple types of therapeutic drugs and/or diagnostic agents (e.g., contrast agents) could be delivered through the same carrier to enable combination therapy with a potential to overcome multidrug resistance, and real-time readout on the treatment efficacy. It is anticipated that precisely engineered nanoparticles will emerge as the next-generation platform for cancer therapy and many other biomedical applications.

Engineered Nanoparticles for Drug Delivery in Cancer Therapy

In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors

Preparation and antibacterial activity of chitosan nanoparticles.

We report the rational design of multifunctional nanoparticles for short-interfering RNA (siRNA) delivery and imaging based on the use of semiconductor quantum dots (QDs) and proton-absorbing polymeric coatings (proton sponges). With a balanced composition of tertiary amine and carboxylic acid groups, these nanoparticles are specifically designed to address longstanding barriers in siRNA delivery such as cellular penetration, endosomal release, carrier unpacking, and intracellular transport. The results demonstrate dramatic improvement in gene silencing efficiency by 10-20 fold and simultaneous reduction in cellular toxicity by 5-6 fold, when compared directly with existing transfection agents for MDA-MB-231 cells. The QD-siRNA nanoparticles are also dual-modality optical and electron-microscopy probes, allowing real-time tracking and ultrastructural localization of QDs during delivery and transfection. These new insights and capabilities represent a major step towards nanoparticle engineering for imaging and therapeutic applications.

https://faculty.washington.edu/xgao/Images/siRNAJACS08.pdf

Proton-Sponge Coated Quantum Dots for siRNA Delivery and Intracellular Imaging

A new generation of nanoparticle carrier that allows efficient delivery and real-time imaging of siRNA in live cells has been developed by combining two distinct types of nanomaterials, semiconductor quantum dots and amphipols. An important finding is that, although amphipols are broadly used for solubilizing and delivering hydrophobic proteins into the lipid bilayers of cell membrane, when combined with nanoparticles, they offer previously undiscovered functionalities, including cytoplasm delivery, siRNA protection, and endosome escape. Compared with the classic siRNA carriers such as Lipofectamine and polyethyleneimine, this new class of nanocarrier works in both serum-free and complete cell culture media, which is advantageous over Lipofectamine. It also outperforms polyethyleneimine in gene silencing under both conditions with significantly reduced toxicity. Furthermore, the intrinsic fluorescence of quantum dots provides a mechanism for real-time imaging of siRNA delivery in live cells. This new mult...

/pdf/quantum-dot-amphipol-nanocomplex-for-intracellular-delivery-21q4uk1lrp.pdf

Quantum dot-amphipol nanocomplex for intracellular delivery and real-time imaging of siRNA.

Lead sorption from aqueous solutions on chitosan nanoparticles

Quantum dots have proven themselves as powerful fluorescent probes, especially for long-term, multiplexed, and quantitative imaging and detection. Newly engineered quantum dots with integrated targeting, imaging and therapeutic functionalities have become excellent material to study drug delivery in cells and small animals. This fluorescent 'prototype' will provide important information in the rational design of biocompatible drug carriers and will serve as a superior alternative to magnetic and radioactive imaging contrast agents in preclinical drug screening, validation and delivery research. This Editorial article is not intended to offer a comprehensive review on drug delivery, but to highlight the breakthroughs in the emerging applications of quantum dots in this field and to provide our perspective on future research.

https://faculty.washington.edu/xgao/Images/QiReview08.pdf

Lifeng Qi

Papers

Preparation and antibacterial activity of chitosan nanoparticles.

Proton-Sponge Coated Quantum Dots for siRNA Delivery and Intracellular Imaging

Quantum dot-amphipol nanocomplex for intracellular delivery and real-time imaging of siRNA.

Lead sorption from aqueous solutions on chitosan nanoparticles

Emerging application of quantum dots for drug delivery and therapy.