Modern radiation therapy using highly automated linear accelerators is a complex process that maximizes doses to tumors and minimizes incident dose to normal tissues. Dosimeters can help determine the radiation dose delivered to target diseased tissue while minimizing damage to surrounding healthy tissue. However, existing dosimeters can be complex to fabricate, expensive, and cumbersome to operate. Here, we demonstrate studies of a liquid phase, visually evaluated plasmonic nanosensor that detects radiation doses commonly employed in fractionated radiotherapy (1-10 Gy) for tumor ablation. We accomplished this by employing ionizing radiation, in concert with templating lipid surfactant micelles, in order to convert colorless salt solutions of univalent gold ions (Au(1)) to maroon-colored dispersions of plasmonic gold nanoparticles. Differences in color intensities of nanoparticle dispersions were employed as quantitative indicators of the radiation dose. The nanoparticles thus formed were characterized using UV-vis absorbance spectroscopy, dynamic light scattering, and transmission electron microscopy. The role of lipid surfactants on nanoparticle formation was investigated by varying the chain lengths while maintaining the same headgroup and counterion; the effect of surfactant concentration on detection efficacy was also investigated. The plasmonic nanosensor was able to detect doses as low as 0.5 Gy and demonstrated a linear detection range of 0.5-2 Gy or 5-37 Gy depending on the concentration of the lipid surfactant employed. The plasmonic nanosensor was also able to detect radiation levels in anthropomorphic prostate phantoms when administered together with endorectal balloons, indicating its potential utility as a dosimeter in fractionated radiotherapy for prostate cancer. Taken together, our results indicate that this simple visible nanosensor has strong potential to be used as a dosimeter for validating delivered radiation doses in fractionated radiotherapies in a variety of clinical settings.

Ever since the discovery of radioactivity,b eneficial use of ionizing radiation has been pursued for the betterment of human health. In particular, fractionated radiotherapy is commonlyu sed in the clinic fora blation of malignant tumors. Use of higher radiation dose fractionsa nd complex dose trajectories necessitate measurements of radiation dose delivered to the target tissue and surrounding tissues in order to ensure patient safety.T raditional dosimeters including polymer gel dosimeters, radiochromic films and metal-oxide semiconductor field effect transistors (MOSFETs) suffer from limitations, whichc omplicate their day-to-day use in the clinic. Molecular and nanoscale systems offer great potentialf or the development of effective sensors of ionizingr adiation,w hich can lead to quantitative dosimeters in biological settings. Thisr eview discusses recent developments based on organic and inorganic molecular and nanoscale dosimeters including quantum dots,p olymers and plasmonic nanoparticles as platforms for radiation sensing. Potential advantages and challenges of translating these technologiestoc linical applicationsare also discussed.

Electrochemical pseudocapacitors are an attractive choice for energy storage applications because they offer higher energy densities than electrostatic or electric double layer capacitors. They also offer higher power densities in shorter durations of time, as compared to batteries. Recent efforts on pseudocapacitors include biocompatible hydrogel electrolytes and transition metal electrodes for implantable energy storage applications. Pseudocapacitive behavior in these devices has been attributed to the redox reactions that occur within the electric double layer, which is formed at the electrode-electrolyte interface. In the present study, we describe a detailed investigation on redox reactions responsible for pseudocapacitive behavior in glycoside-containing hydrogel formulations. Pseudocapacitive behavior was compared among various combinations of biocompatible hydrogel electrolytes, using carbon tape electrodes and transition metal electrodes based on fluorine-doped tin oxide. The hydrogels demonstrated a pseudocapacitive response only in the presence of transition metal electrodes but not in the presence of carbon electrodes. Hydrogels containing amine moieties showed greater energy storage than gels based purely on hydroxyl functional groups. Furthermore, energy storage increased with greater amine content in these hydrogels. We claim that the redox reactions in hydrogels are largely based on Lewis acid-base interactions, facilitated by amine and hydroxyl side groups along the electrolyte chain backbones, as well as hydroxylation of electrode surfaces. Water plays an important role in these reactions, not only in terms of providing ionic radicals but also in assisting ion transport. This understanding of redox reactions will help determine the choice of transition metal electrodes, Lewis acid-base pairs in electrolytes, and medium for ionic transport in future biocompatible pseudocapacitors.

Exosomes are nanoscale extracellular vesicles that encapsulate a diverse range of biomolecules such as nucleic acids, proteins, and lipids. They are involved in several biological processes and mediate intracellular communication. Recent reports that they exhibit unique traits in pathological conditions have generated significant interest in employing them as diagnostic and therapeutic tools. Particularly, their potential to serve as drug delivery vehicles for the treatment of cancer and other diseases has been explored in numerous studies. This manuscript reviews recent developments in the field and discusses important considerations for further refinement of this approach and realization of more effective exosome-based drug delivery systems.

Nanoparticles have numerous uses in biomedical sciences, and this study addresses the mechanisms responsible for the formation of gold nanoparticles (GNPs) for measuring doses of ionizing radiation used in clinical radiotherapy. GNPs synthesized at various radiation doses were experimentally characterized and two mathematical models were developed to simulate the kinetics of the synthesis process. The first is similar to the Fink-Watzke model and predicts the rate of soluble gold salt conversion to GNPs, and the second model is based on a population balance model and predicts both nanoparticle concentration and size distribution. The model parameters that provided an optimal fit to experimentally gathered data were determined, and both models were able to capture the experimental absorbance time trends, which indicated the formation of gold nanoparticles. The population balance model, however, had the greater predictive power as it captured mean particle size trends that were consistent with experimental measurements.