Revealing Population Heterogeneity in Vesicle-Based Nanomedicines Using Automated, Single Particle Raman Analysis.

The intrinsic heterogeneity of many nanoformulations is currently challenging to characterize on both the single particle and population level. Therefore, there is great opportunity to develop advanced techniques to describe and understand nanomedicine heterogeneity, which will aid translation to the clinic by informing manufacturing quality control, characterization for regulatory bodies, and connecting nanoformulation properties to clinical outcomes to enable rational design. Here, we present an analytical technique to provide such information, while measuring the nanocarrier and cargo simultaneously with label-free, nondestructive single particle automated Raman trapping analysis (SPARTA). We first synthesized a library of model compounds covering a range of hydrophilicities and providing distinct Raman signals. These compounds were then loaded into model nanovesicles (polymersomes) that can load both hydrophobic and hydrophilic cargo into the membrane or core regions, respectively. Using our analytical framework, we characterized the heterogeneity of the population by correlating the signal per particle from the membrane and cargo. We found that core and membrane loading can be distinguished, and we detected subpopulations of highly loaded particles in certain cases. We then confirmed the suitability of our technique in liposomes, another nanovesicle class, including the commercial formulation Doxil. Our label-free analytical technique precisely determines cargo location alongside loading and release heterogeneity in nanomedicines, which could be instrumental for future quality control, regulatory body protocols, and development of structure-function relationships to bring more nanomedicines to the clinic.

Modular Synthesis of Semiconducting Graft Copolymers to Achieve "Clickable" Fluorescent Nanoparticles with Long Circulation and Specific Cancer Targeting.

Semiconducting polymer nanoparticles (SPNs) are explored for applications in cancer theranostics because of their high absorption coefficients, photostability, and biocompatibility. However, SPNs are susceptible to aggregation and protein fouling in physiological conditions, which can be detrimental for in vivo applications. Here, a method for achieving colloidally stable and low-fouling SPNs is described by grafting poly(ethylene glycol) (PEG) onto the backbone of the fluorescent semiconducting polymer, poly(9,9'-dioctylfluorene-5-fluoro-2,1,3-benzothiadiazole), in a simple one-step substitution reaction, postpolymerization. Further, by utilizing azide-functionalized PEG, anti-human epidermal growth factor receptor 2 (HER2) antibodies, antibody fragments, or affibodies are site-specifically "clicked" onto the SPN surface, which allows the functionalized SPNs to specifically target HER2-positive cancer cells. In vivo, the PEGylated SPNs are found to have excellent circulation efficiencies in zebrafish embryos for up to seven days postinjection. SPNs functionalized with affibodies are then shown to be able to target HER2 expressing cancer cells in a zebrafish xenograft model. The covalent PEGylated SPN system described herein shows great potential for cancer theranostics.

Employing defined bioconjugates to generate chemically functionalised gold nanoparticles for in vitro diagnostic applications.

Novel methods for introducing chemical and biological functionality to the surface of gold nanoparticles serve to increase the utility of this class of nanomaterials across a range of applications. To date, methods for functionalising gold surfaces have relied upon uncontrollable non-specific adsorption, bespoke chemical linkers, or non-generalisable protein-protein interactions. Herein we report a versatile method for introducing functionality to gold nanoparticles by exploiting the strong interaction between chemically functionalised bovine serum albumin (f-BSA) and citrate-capped gold nanoparticles (AuNPs). We establish the generalisability of the method by introducing a variety of functionalities to gold nanoparticles using cheap, commercially available chemical linkers. The utility of this approach is further demonstrated through the conjugation of the monoclonal antibody Ontruzant to f-BSA-AuNPs using inverse electron-demand Diels-Alder (iEDDA) click chemistry, a hitherto unexplored chemistry for AuNP-IgG conjugation. Finally, we show that the AuNP-Ontruzant particles generated via f-BSA-AuNPs have a greater affinity for their target in a lateral flow format when compared to conventional physisorption, highlighting the potential of this technology for producing sensitive diagnostic tests.

A double-blinded, prospective randomized controlled trial of intraperitoneal bupivacaine in laparoscopic Roux-en-Y gastric bypass.

BACKGROUND: Intraperitoneal local anesthetics have been investigated in several laparoscopic procedures that demonstrate improved postoperative pain control and reduced length of hospital stay. No published studies to date address the effectiveness of IP local anesthetics in laparoscopic gastric bypass patients (LRYGB). STUDY DESIGN: Between October 2004 and March 2005, 133 patients were prospectively studied to evaluate the efficacy of IP bupivacaine (IPB) in LRYGB. Patients were randomized to receive either bupivacaine (study group) or saline (control group), which was administered over the esophageal hiatus before dissection and bypass. All procedures were performed in a University-affiliated community-based hospital by three experienced laparoscopic gastric bypass surgeons. Outcomes variables included postoperative pain and narcotic use, length of stay, antiemetic use, cost, and pulmonary function. RESULTS: There were 65 patients within the study group and 68 control patients, with equivalent patient demographics (p > 0.05). A statistically significant decrease in oral narcotic (hydrocodone/acetaminophen, Lortab Elixir, UCB) use was seen in the experimental group relative to the control group (23.8 +/- 2.2 mL versus 33.7 +/- 3.0 mL). Material cost was greater by $0.36 per patient in the study group. All other outcomes variables (ie, length of stay, postoperative IV narcotic use, incentive spirometer volumes, visual analog pain scale, and antiemetic use) showed no considerable differences. CONCLUSIONS: IPB use during LRYGB revealed a statistically significant difference only in postoperative oral narcotic use. Possibly, the IPB can limit or prevent peritoneal irritation and reduce the need for longer narcotic use. Clinical significance was not demonstrated by our outcomes variables.

The science of stapling and leaks.

Staple-line leaks represent an unwanted, yet seemingly unavoidable, complication of stapling associated with bariatric surgery. Although, "folk legends" abound as to precluding leaks, little has been written based on basic research and understanding of stapling mechanics. This article reviews the history of stapling and discusses the implications of understanding the biomechanics of stapling living tissue. Finally, three leak studies evaluating ways to optimize staple-line strength are presented, and a large bariatric clinical series is reviewed.

A randomized trial of endoscopic and fluoroscopic placement of postpyloric feeding tubes in critically ill patients.

BACKGROUND: Early postpyloric feeding is considered the accepted method of nutrition support in critically ill patients. Endoscopic and fluoroscopic techniques are associated with the highest percentage of successful placement. The purpose of this study was to compare endoscopic vs fluoroscopic placement of postpyloric feeding tubes in critically ill patients. METHODS: This is a randomized prospective clinical trial. Forty-three patients were randomized to receive feeding tubes by endoscopic or fluoroscopic technique. All procedures were performed at the bedside in the critical care unit. A soft small-bore nonweighted feeding tube was used in all cases. Successful placement was confirmed by either an abdominal x-ray for endoscopic technique or a fluoroscopic radiograph for fluoroscopic technique. RESULTS: Postpyloric feeding tubes were successfully placed in 41 of 43 patients (95%). The success rate using endoscopic technique was 96% (25 of 26), whereas the rate using fluoroscopy was 94% (16 of 17). The average time of successful placement was 15.2 +/- 2.9 (mean +/- SEM) minutes for endoscopic placement and 16.2 +/- 3.2 minutes for fluoroscopic placement, which was not statistically significant (p > .05). CONCLUSIONS: Endoscopic and fluoroscopic placement of postpyloric feeding tubes can safely and accurately be performed at the bedside in critically ill patients. Our results showed no significant difference in the success rate or time of placement between endoscopic vs fluoroscopic placement of postpyloric feeding tubes.