An implantable microdevice to perform high-throughput in vivo drug sensitivity testing in tumors

Current anticancer chemotherapy relies on a limited set of in vitro or indirect prognostic markers of tumor response to available drugs. A more accurate analysis of drug sensitivity would involve studying tumor response in vivo. To this end, we have developed an implantable device that can perform drug sensitivity testing of several anticancer agents simultaneously inside the living tumor. The device contained reservoirs that released microdoses of single agents or drug combinations into spatially distinct regions of the tumor. The local drug concentrations were chosen to be representative of concentrations achieved during systemic treatment. Local efficacy and drug concentration profiles were evaluated for each drug or drug combination on the device, and the local efficacy was confirmed to be a predictor of systemic efficacy in vivo for multiple drugs and tumor models. Currently, up to 16 individual drugs or combinations can be assessed independently, without systemic drug exposure, through minimally invasive biopsy of a small region of a single tumor. This assay takes into consideration physiologic effects that contribute to drug response by allowing drugs to interact with the living tumor in its native microenvironment. Because these effects are crucial to predicting drug response, we envision that these devices will help identify optimal drug therapy before systemic treatment is initiated and could improve drug response prediction beyond the biomarkers and in vitro and ex vivo studies used today. These devices may also be used in clinical drug development to safely gather efficacy data on new compounds before pharmacological optimization.

Intracellular delivery of core-shell fluorescent silica nanoparticles

Highly fluorescent core-shell silica nanoparticles made by the modified Stöber process (C dots) are promising as tools for sensing and imaging subcellular agents and structures but will only be useful if they can be easily delivered to the cytoplasm of the subject cells. This work shows that C dots can be electrostatically coated with cationic polymers, changing their surface charge and enabling them to escape from endosomes and enter the cytoplasm and nucleus. As an example of cellular delivery, we demonstrate that these particles can also be complexed with DNA and mediate and trace DNA delivery and gene expression.

Scoliosis surgery: a risk factor for cholelithiasis?

Scoliosis surgery has been associated with pancreatitis and acalculous cholecystitis, and also has been implicated as a risk factor for cholelithiasis. A prospective study of 36 children and adolescents undergoing scoliosis surgery was performed using ultrasound to determine the incidence of cholelithiasis following spine surgery. The patients underwent abdominal ultrasound exams preoperatively, immediately postoperatively, and then at intervals following surgery with 2-5-year follow-up. Four of 36 patients (11.1%) (one male, three female) developed gallstones, although all had been free of gallstones after surgery. The gallstones appeared between 2 + 5 and 5 years after surgery. Those with gallstones were not different from those without with respect to 14 factors. It is concluded that scoliosis surgery is not a risk factor for gallstones, because of the delay in onset of cholelithiasis after surgery. Furthermore, the prevalence of gallstones in this study sample is not greater than that reported in historical control studies of European young adults.