Interactions of composite gold nanoparticles with cells and tissue : implications in clinical translation for cancer imaging and therapy

textCurrent methods to diagnose and treat cancer often involve expensive, time-consuming equipment and materials that may lead to unwanted side effects and may not even increase a patient’s chance of survival. Thus, for a while now, a large part of the research community has focused on developing improved methods to detect, diagnose, and treat cancer on the molecular scale. One of the most recently discovered methods of cancer therapy is targeted therapy. These targeted therapies have potential to provide a patient with a form of personalized medicine because these therapies are biological molecules that specifically target other molecules involved with a cancer’s growth. Past trials using these therapeutic molecules, however, have led to controversial results, where certain patients responded better than others to the therapy for unknown reasons. Elucidating the reason behind these mixed results can be accomplished using metal nanoparticle technologies which could provide a bright signal to monitor the path that these therapeutic molecules take in vivo as well as enhance the molecule’s efficacy. Literature has shown that presenting targeting molecules in a dense manner to their target will increase these molecules’ binding affinity. This concept has been explored here to increase binding affinity of therapeutic molecules by attaching these molecules in a dense manner on the surface of gold nanoparticles, and correlating this increased affinity with therapeutic efficacy. Additionally, gold nanoparticles provide an easy surface for molecules to be functionalized on and have shown to be effective imaging, x-ray, and photothermal therapy agents. A major roadblock to using these gold nanoparticles clinically is their non-degradability and thus potential to cause long-term negative side effects in vivo. A platform for developing biodegradable gold nanoparticles is also explored here to take advantage of the gold nanoparticles’ excellent imaging and drug delivery capabilities while still allowing them to be used safely in the long term.Biomedical Engineerin

Extinction Coefficient of Gold Nanostars

Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis, and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPRs), which range from 5.7 × 10⁸ to 26.8 × 10⁸ M⁻¹ cm⁻¹. Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.United States. National Institutes of Health (AI100190

Rapid Diagnostics for Infectious Disease using Noble Metal Nanoparticles

Rapid point-of-care (POC) diagnostic devices are needed for field-forward screening of severe acute systemic febrile illnesses such as dengue, Ebola, chikungunya, and others. Multiplexed rapid lateral flow diagnostics have the potential to distinguish among multiple pathogens, thereby facilitating diagnosis and improving patient care. We present a platform for multiplexed pathogen detection which uses gold or silver nanoparticles conjugated to antibodies to sense the presence of biomarkers for different infectious diseases. We exploit the size-dependent optical properties of Ag NPs to construct a multiplexed paperfluidic lateral flow POC sensor. AgNPs of different sizes were conjugated to antibodies that bind to specific biomarkers. Red AgNPs were conjugated to antibodies that could recognize the glycoprotein for Ebola virus, green AgNPs to those that could recognize nonstructural protein 1 for dengue virus, and orange AgNPs for non structural protein 1 for yellow fever virus. Presence of each of the biomarkers resulted in a different colored band on the test line in the lateral flow test. Thus, we were able to use NP color to distinguish among three pathogens that cause a febrile illness. Because positive test lines can be imaged by eye or a mobile phone camera, the approach is adaptable to low-resource, widely deployable settings. This design requires no external excitation source and permits multiplexed analysis in a single channel, facilitating integration and manufacturing. We will also discuss engineering the nanoparticle physical properties and surface chemistry for improving detection and also optimizing device properties, and expansion of the device to detect other diseases

Empirical treatment against cytomegalovirus and tuberculosis in HIV-infected infants with severe pneumonia: study protocol for a multicenter, open-label randomized controlled clinical trial.

BACKGROUND: Pneumonia is the primary cause of death among HIV-infected children in Africa, with mortality rates as high as 35-40% in infants hospitalized with severe pneumonia. Bacterial pathogens and Pneumocystis jirovecii are well known causes of pneumonia-related death, but other important causes such as cytomegalovirus (CMV) and tuberculosis (TB) remain under-recognized and undertreated. The immune response elicited by CMV may be associated with the risk of developing TB and TB disease progression, and CMV may accelerate disease caused both by HIV and TB. Minimally invasive autopsies confirm that CMV and TB are unrecognized causes of death in children with HIV. CMV and TB may also co-infect the same child. The aim of this study is to compare the impact on 15-day and 1-year mortality of empirical treatment against TB and CMV plus standard of care (SoC) versus SoC in HIV-infected infants with severe pneumonia. METHODS: This is a Phase II-III, open-label randomized factorial (2 × 2) clinical trial, conducted in six African countries. The trial has four arms. Infants from 28 to 365 days of age HIV-infected and hospitalized with severe pneumonia will be randomized (1:1:1:1) to (i) SoC, (ii) valganciclovir, (iii) TB-T, and (iv) TB-T plus valganciclovir. The primary endpoint of the study is all-cause mortality, focusing on the short-term (up to 15 days) and long-term (up to 1 year) mortality. Secondary endpoints include repeat hospitalization, duration of oxygen therapy during initial admission, severe and notable adverse events, adverse reactions, CMV and TB prevalence at enrolment, TB incidence, CMV viral load reduction, and evaluation of diagnostic tests such as GeneXpert Ultra on fecal and nasopharyngeal aspirate samples and urine TB-LAM. DISCUSSION: Given the challenges in diagnosing CMV and TB in children and results from previous autopsy studies that show high rates of poly-infection in HIV-infected infants with respiratory disease, this study aims to evaluate a new approach including empirical treatment of CMV and TB for this patient population. The potential downsides of empirical treatment of these conditions include toxicity and medication interactions, which will be evaluated with pharmacokinetics sub-studies. TRIAL REGISTRATION: ClinicalTrials.gov , NCT03915366, Universal Trial Number U111-1231-4736, Pan African Clinical Trial Registry PACTR201994797961340

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Minimally Invasive Approaches in the Treatment of Pelvic Organ Prolapse: Laparoscopic and Robotic - 31

Pelvic organ prolapse is a common disease process in women as the descent of the pelvic organs is a multifactorial process. Approximately 40% of women have some degree of prolapse on exam. However, when examined by degree of bother, the prevalence of symptomatic prolapse is less – ranging from 3% to 6% of parous women. For women who are symptomatic and bothered by prolapse, the treatment options are conservative management, pelvic floor physical therapy, pessary use, and surgery. Surgery for prolapse has remained an important option for women to restore pelvic anatomy, improve prolapse symptoms, and maintain quality of life. With the advancement of minimally invasive surgical techniques, the morbidity of pelvic organ prolapse surgery has decreased. Minimally invasive surgery (MIS) approaches have revolutionized and advanced contemporary pelvic organ prolapse surgery. Minimally invasive prolapse surgeries, both laparoscopic and robotic-assisted laparoscopic, have benefited women by facilitating apical support through smaller incisions and with improved visualization. With the advancement of minimally invasive surgical techniques, the morbidity of pelvic organ prolapse surgery has decreased. Surgery for prolapse has remained an important option for women to restore pelvic anatomy, improve prolapse symptoms, and maintain quality of life

Multicolored silver nanoparticles for multiplexed disease diagnostics: distinguishing dengue, yellow fever, and Ebola viruses

Rapid point-of-care (POC) diagnostic devices are needed for field-forward screening of severe acute systemic febrile illnesses. Multiplexed rapid lateral flow diagnostics have the potential to distinguish among multiple pathogens, thereby facilitating diagnosis and improving patient care. Here, we present a platform for multiplexed pathogen detection using multi-colored silver nanoplates. This design requires no external excitation source and permits multiplexed analysis in a single channel, facilitating integration and manufacturing.National Institutes of Health (U.S.) (NIH NIAID (AI100190))SUTD-MIT International Design Centre (IDC