Breast-conserving surgery (BCS) is for patients diagnosed with early-stage breast cancer or those who have responded well to neoadjuvant chemotherapy prior to their surgery. While the success rate is high, the risk of BCS is that there could be recurrence, requiring a second surgery with more than 30% rate, for both ipsilateral and systemic cases.¹ The standard of care requires complete removal of cancerous regions by lumpectomy, leaving no positive margins detected at the time of surgery. The common practice to confirm a successful surgery is a histopathology reading of the hematoxylin and eosin (H&E)-stained slides of the post-lumpectomy sample to confirm a negative or clear margin, where the ductal carcinoma in situ should not be found within a 2 mm distance from all specimen edges² or no invasive cancer should be found on any exposed margin surface. With positive or close superficial surgical margins, mastectomy or re-excision should follow within days or weeks, following surgery. The delay in re-excision is sometimes due to the delay in histopathology results. Ideally, an accurate image-guide surgery or an immediate post-lumpectomy evaluation of the margin could be done, to avoid delays to surgery, if positive margins are discovered.

Development of UV-weathered micro- and nanoplastic controls for overcoming challenges associated with accurate chemical identification.

Despite the great potential of using positively charged gold nanoparticles (AuNPs) in nanomedicine, no systematic studies have been reported on their synthesis optimization or colloidal stability under physiological conditions until a group at the National Institute of Standards and Technology recently succeeded in producing remarkably stable polyethyleneimine (PEI)-coated AuNPs (Au-PEI). This improved version of Au-PEI (Au-PEI25kB) has increased the demand for toxicity and teratogenicity information for applications in nanomedicine and nanotoxicology. In vitro assays for Au-PEI25kB in various cell lines showed substantial active cytotoxicity. For advanced toxicity research, the frog embryo teratogenesis assay–Xenopus (FETAX) method was employed in this study. We observed that positively-charged Au-PEI25kB exhibited significant toxicity and teratogenicity, whereas polyethylene glycol conjugated AuNPs (Au-PEG) used as comparable negative controls did not. There is a characteristic avidity of Au-PEI25kB for the jelly coat, the chorionic envelope (also known as vitelline membrane) and the cytoplasmic membrane, as well as a barrier effect of the chorionic envelope observed with Au-PEG. To circumvent these characteristics, an injection-mediated FETAX approach was utilized. Like treatment with the FETAX method, the injection of Au-PEI25kB severely impaired embryo development. Notably, the survival/concentration curve that was steep when the standard FETAX approach was employed became gradual in the injection-mediated FETAX. These results suggest that Au-PEI25kB may be a good candidate as a nanoscale positive control material for nanoparticle analysis in toxicology and teratology.