Increasing biomedical applications of iron oxide nanoparticles (IONPs) in academic and commercial settings have alarmed the scientific community about the safety and assessment of toxicity profiles of IONPs. The great amount of diversity found in the cytotoxic measurements of IONPs points toward the necessity of careful characterization and quantification of IONPs. The present document discusses the major developments related to in vitro and in vivo toxicity assessment of IONPs and its relationship with the physicochemical parameters of IONPs. Major discussion is included on the current spectrophotometric and imaging based techniques used for quantifying, and studying the clearance and biodistribution of IONPs. Several invasive and non-invasive quantification techniques along with the pitfalls are discussed in detail. Finally, critical guidelines are provided to optimize the design of IONPs to minimize the toxicity.

A novel ex vivo model combining cell printing and tissue culture to investigate cancer cell dynamics during angiogenesis in intact microvascular networks.

Epithelial-adipose interaction is an integral step in breast cancer cell invasion and progression towards lethal metastatic disease. Understanding the physiological contribution of obesity, a major contributor to breast cancer risk and negative prognosis in post-menopausal patients, on cancer cell invasion requires detailed co-culture constructs that reflect mammary microarchitecture. Using laser direct-write, a laser-based CAD/CAM bioprinting technique, we have demonstrated the ability to construct breast cancer cell-laden hydrogel microbeads into spatially defined patterns in hydrogel matrices containing differentiated adipocytes. Z -stack imaging confirmed the three-dimensional nature of the constructs, as well as incorporation of cancer cell-laden microbeads into the adipose matrix. Preliminary data was gathered to support the construct as a potential model for breast cancer cell invasion into adipose tissue. MCF-7 and MDA-MB-231 breast cancer cell invasion was tracked over 2 weeks in an optically transparent hydrogel scaffold in the presence of differentiated adipocytes obtained from normal weight or obese patient tissue. Our model successfully integrates adipocytes and gives us the potential to study cellular and tissue-level interactions towards the early detection of cancer cell invasion into adipose tissue.

We report a photonic technique to instantaneously synthesize cobalt oxide reduced graphitic oxide (CoO_x-rGO) supercapacitor electrodes. The electrode processing is achieved through rapidly heating the precursor material by irradiation of high-energy pulsed mostly visible light from a xenon lamp. Due to the short duration of the light pulse, we prepared the electrodes at room temperature instantaneously (ms), thus eliminating the several hours of processing times of the conventional techniques. The as-prepared electrodes exhibited a highly porous morphology, allowing for enhanced ionic transport during electrochemical interactions. The electrochemical properties of the CoO_x-rGO electrodes were studied in 1 M KOH aqueous electrolyte. The non-rectangular cyclic voltammetry (CV) curves with characteristic redox peaks indicated the pseudocapacitive charge storage mechanism of the electrodes. From the discharge curves at 0.4 mA/cm² and 1.6 A/g constant current densities, the electrode showed areal specific capacitance of 17 mF/cm² and specific capacitance of 69 F/g, respectively. Cyclic stability was tested by performing 30,000 galvanostatic charge–discharge (GCD) cycles and the electrode exhibited 65% capacitance retention, showing its excellent electrochemical performance and ultra-long cycle life. The excellent electrochemical electrode properties are attributed to the unique processing technique, optimum processing parameters, improved conductivity due to the presence of rGO, and highly porous morphology which offers a high specific surface area. The novel photonic processing we report allows for high-temperature heating of the precursor films achieved via non-radiative recombination of photogenerated electron holes pairs during irradiation. Such extremely quick (ms) heating followed by instantaneous cooling results in the formation of a dense and robust bottom layer of the electrode, resulting in a long cycle life.