Gold nanorods (AuNRs)-assisted plasmonic photothermal therapy (AuNRs-PPTT) is a promising strategy for combating cancer in which AuNRs absorb near-infrared light and convert it into heat, causing cell death mainly by apoptosis and/or necrosis. Developing a valid PPTT that induces cancer cell apoptosis and avoids necrosis in vivo and exploring its molecular mechanism of action is of great importance. Furthermore, assessment of the long-term fate of the AuNRs after treatment is critical for clinical use. We first optimized the size, surface modification [rifampicin (RF) conjugation], and concentration (2.5 nM) of AuNRs and the PPTT laser power (2 W/cm2) to achieve maximal induction of apoptosis. Second, we studied the potential mechanism of action of AuNRs-PPTT using quantitative proteomic analysis in mouse tumor tissues. Several death pathways were identified, mainly involving apoptosis and cell death by releasing neutrophil extracellular traps (NETs) (NETosis), which were more obvious upon PPTT using RF-conjugated AuNRs (AuNRs@RF) than with polyethylene glycol thiol-conjugated AuNRs. Cytochrome c and p53-related apoptosis mechanisms were identified as contributing to the enhanced effect of PPTT with AuNRs@RF. Furthermore, Pin1 and IL18-related signaling contributed to the observed perturbation of the NETosis pathway by PPTT with AuNRs@RF. Third, we report a 15-month toxicity study that showed no long-term toxicity of AuNRs in vivo. Together, these data demonstrate that our AuNRs-PPTT platform is effective and safe for cancer therapy in mouse models. These findings provide a strong framework for the translation of PPTT to the clinic.

https://www.pnas.org/content/pnas/114/15/E3110.full.pdf

Efficacy, long-term toxicity, and mechanistic studies of gold nanorods photothermal therapy of cancer in xenograft mice.

Over recent decades, one of the most important and complex problems facing our society is the multi-drug resistance of human cancer cells and pathogens to most clinically approved therapeutics. Recent advances in nanoscience and nanotechnology have expanded our ability to design and construct nanomaterials with targeting, therapeutic, and diagnostic functions. These multifunctional materials have gained attention as promising tools for selective cancer/bacteria therapy in the absence of current drugs. Photothermal therapy (PTT) is a minimally invasive therapy in which photon energy is converted into heat in order to kill cancer cells. Gold nanoparticles (GNPs) with a high light-to-heat conversion capability are among the most important candidates for PTT. GNP-assisted PTT has shown great success in recent years, suggesting promise for future applications. In this review, we will discuss the current status of GNPs in the photothermal treatment of cancer and bacterial conditions. The review starts with an outline of recent developments in the various methods used for the size- and shape-controlled synthesis of GNPs, followed by a discussion of the modification of GNPs using suitable protecting and functionalizing agents. We will then consider therapeutic outcomes of different types of GNP-assisted PTT in cancer therapy and bactericide through a comprehensive review of the most important results obtained both in vivo and in vitro. The advantages and disadvantages of methods for developing different-shaped GNPs, variations in irradiation conditions, the use of PTT in combination with other therapeutic methods, and a comparison between the PTT efficacies of different-shaped GNPs will also be discussed in detail.

Engineered gold nanoparticles for photothermal cancer therapy and bacteria killing

The ongoing COVID-19 pandemic has brought forward the centrality of public communication as a force for information, and in highlighting the differential impact on diverse segments of the society. Information and communication technologies-led developments including social media have previously been discussed as instruments of democratization of knowledge. However, the evidence so far shows that the promise remains unfulfilled as upper socioeconomic groups acquire information at a faster rate than others. The communication inequalities have only reinforced the existing societal fault lines of race, class and place. As the first pandemic of the social media age, COVID-19 has also given rise to an "infodemic", providing fertile ground for the spread of information, misinformation and disinformation. With limited gatekeeping, an immense amount of unprocessed scientific information is being put forward to publics not trained in science. In this commentary, we offer some propositions on how disinformation on COVID-19 has become mainstreamed through social media's spiral of amplification and what role public communication has in an emergency from a lens of equity. We raise the question of whether the tremendous flow of scientific information during the COVID-19 pandemic has a differential impact on different socioeconomic groups. We propose that more systematic research is urgently needed to understand how mis/disinformation originate, spread and what their consequences are. In our view, research in health communication inequalities is foundational to mitigating the current off-line and online ravages of the pandemic.

https://www.tandfonline.com/doi/pdf/10.1080/10410236.2020.1837445

We Need the Lens of Equity in COVID-19 Communication.

Stimuli-responsive porous polymer materials have promising biomedical application due to their ability to trap and release biomacromolecules. In this work, a class of highly porous electrospun fibers is designed using polylactide as the polymer matrix and poly(ethylene oxide) as a porogen. Carbon nanotubes (CNTs) with different concentrations are further impregnated onto the fibers to achieve self-sealing functionality induced by photothermal conversion upon light irradiation. The fibers with 0.4 mg mL−1 of CNTs exhibit the optimum encapsulation efficiency of model biomacromolecules such as dextran, bovine serum albumin, and nucleic acids, although their photothermal conversion ability is slightly lower than the fibers with 0.8 mg mL−1 of CNTs. Interestingly, reversible reopening of the surface pores is accomplished with the degradation of PLA, affording a further possibility for sustained release of biomacromolecules after encapsulation. Effects of CNT loading on fiber morphology, structure, thermal/mechanical properties, degradation, and cell viability are also investigated. This novel class of porous electrospun fibers with self-sealing capability has great potential to serve as an enabling strategy for trapping/release of biomacromolecules with promising applications in, for example, preventing inflammatory diseases by scavenging cytokines from interstitial body fluids.

Porous Electrospun Fibers with Self‐Sealing Functionality: An Enabling Strategy for Trapping Biomacromolecules

Drug-loaded poly (ε-caprolactone)/Fe 3 O 4 composite microspheres for magnetic resonance imaging and controlled drug delivery

The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms. Schematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion droplets, eventually solidifying them into nanoparticles. It is a simple but effective nanoencapsulation technique that has advantages over typical solvent evaporation and/or extraction methods.

Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

The objective of this study was to develop a new oil-in-water emulsion template for the preparation of highly porous poly(lactide-co-glycolide) (PLGA) microspheres having a spongelike skeleton and a pore-closing functionality. A dispersed phase consisting of isopropyl formate and PLGA was emulsified in an aqueous phase. Ammonia was added toward this emulsion, in order to induce ammonolysis in the dispersed phase. Subsequently, isopropyl formate was broken into water-soluble isopropanol and formamide. As they functioned as anti-solvents against PLGA, microsphere hardening occurred. Also, their leaching into the aqueous phase led to the formation of highly porous, spongelike microspheres. The microsphere porosity was found to be controlled by adjusting isopropyl formate volume, PLGA type and concentration, ammonia volume, and ammonia–isopropyl formate molar ratio. When these dried microspheres were dispersed into an aqueous phase, the pores closed themselves autonomously. Herein, the self-closing capability of the microspheres was greatly influenced by microsphere Tg and the aqueous phase temperature. FITC-dextran and lysozyme were successfully encapsulated into the microspheres by simply equilibrating their aqueous solutions with the self-closing microspheres. In conclusion, the new emulsion template did not use either a halogenated organic solvent or conventional porogens. It did not require high-shear or high-energy mixing devices that must be used in the practice of most contemporary microencapsulation techniques. Despite these facts, this new technique was able to fabricate spongelike microspheres with an extremely high porosity and an outstanding pore-closing functionality.

Simple emulsion technique as an innovative template for preparation of porous, spongelike poly(lactide- co -glycolide) microspheres with pore-closing capability

Youngme Lee

Papers

Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

Simple emulsion technique as an innovative template for preparation of porous, spongelike poly(lactide- co -glycolide) microspheres with pore-closing capability