Developing a list of core competencies for medical aspects of healthcare delivery in care homes: scoping review and Delphi process.

BACKGROUND: Care home residents live with frailty and multiple long-term conditions. Their medical management is complex and specialised. We set out to develop a list of core competencies for doctors providing medical care in long-term care homes. METHODS: A scoping review searched MEDLINE, EMBASE and CAB Abstracts, supplemented by grey literature from the Portal of Online Geriatrics Education and the International Association of Geriatrics and Gerontology, looking for core competencies for doctors working in care homes. These were mapped to the UK nationally mandated Generic Professional Competencies Framework. A Delphi exercise was conducted over three rounds using a panel of experts in care homes and medicine of older people. Competencies achieving 80% agreement for inclusion/exclusion were rejected/accepted, respectively. RESULTS: The scoping review identified 22 articles for inclusion, yielding 124 competencies over 21 domains. The Delphi panel comprised 23 experts, including 6 geriatricians, 4 nurses, 3 general practitioners, 2 advanced clinical practitioners, 2 care home managers, and one each of a patient and public representative, palliative care specialist, psychiatrist, academic, physiotherapist and care home audit lead. At the end of three rounds, 109 competencies over 19 domains were agreed. Agreement was strongest for generic competencies around frailty and weaker for sub-specialist knowledge about specific conditions and competencies related to care home medical leadership and management. CONCLUSION: The resulting competencies provide the basis of a curriculum for doctors working in long-term care homes for older people. They are specialty agnostic and could be used to train general practitioners or medical specialty doctors.

Predisposing, Enabling, and Need Factors Associated with Psychotropic Medication and Mental Health Service Use among Children in Out-of-Home Care in the United States: A Scoping Review.

This scoping review aimed to identify predisposing, enabling, and need factors associated with the use of mental health services, including psychotropic medications, among children in out-of-home care in the United States. We searched the PsycInfo, SocINDEX, Medline, and Scopus databases, and 22 studies met inclusion criteria and were systematically analyzed. Among the included studies, 7 studies examined predictors associated with taking psychotropic medications, and 16 examined factors associated with using other mental health services. Significant predisposing, enabling, and need factors associated with greater use of mental health services, including psychotropic medications, were identified. The most frequently identified predisposing factors were child race/ethnicity, age, gender, and maltreatment. Important enabling factors were out-of-home placement type and length of care, and need factors included children's mental/behavioral problems. The results provide insight into maximizing factors facilitating children's use of mental health services to address mental health problems of children in out-of-home care. Further, the results imply the importance of the appropriate use of psychotropic medication (e.g., the type and dosage of medications) among children in out-of-home care. The identified factors can inform child welfare agencies and stakeholders on ways to improve access to mental health services and the appropriate use of psychotropic medications among children in out-of-home care in the United States.

Chiral Plasmonic Pinwheels Exhibit Orientation-Independent Linear Differential Scattering under Asymmetric Illumination.

Plasmonic nanoantennas have considerably stronger polarization-dependent optical properties than their molecular counterparts, inspiring photonic platforms for enhancing molecular dichroism and providing fundamental insight into light-matter interactions. One such insight is that even achiral nanoparticles can yield strong optical activity when they are asymmetrically illuminated from a single oblique angle instead of evenly illuminated. This effect, called extrinsic chirality, results from the overall chirality of the experimental geometry and strongly depends on the orientation of the incident light. Although extrinsic chirality has been well-characterized, an analogous effect involving linear polarization sensitivity has not yet been discussed. In this study, we investigate the differential scattering of rotationally symmetric chiral plasmonic pinwheels when asymmetrically irradiated with linearly polarized light. Despite their high rotational symmetry, we observe substantial linear differential scattering that is maintained over all pinwheel orientations. We demonstrate that this orientation-independent linear differential scattering arises from the broken mirror and rotational symmetries of our overall experimental geometry. Our results underscore the necessity of considering both the rotational symmetry of the nanoantenna and the experimental setup, including illumination direction and angle, when performing plasmon-enhanced chiroptical characterizations. Our results demonstrate spectroscopic signatures of an effect analogous to extrinsic chirality for linear polarizations.

Prior vertical uterine incision: Effect on subsequent pregnancy characteristics and outcomes.

OBJECTIVE: To examine characteristics and outcomes of cesarean delivery (CD) in women with a history of vertical hysterotomy. METHOD: This is a comparative study that retrospectively queried the National Inpatient Sample from October 2016 to December 2018. Pregnancy characteristics and surgical outcomes of CD among 18 575 women with prior vertical uterine incision were compared to 1 072 949 women with prior low-transverse incision, assessed by multivariable generalized estimating equation model and propensity score weighting. RESULTS: In a multivariable analysis, women who had prior vertical uterine incision were more likely to have placenta percreta (odds ratio [OR] 3.41, 95% confidence interval [CI] 1.87-6.20), pre-labor uterine rupture (OR 2.70, 95% CI 1.52-4.80), in-labor uterine rupture (OR 2.33, 95% CI 1.55-3.51), and extreme preterm delivery <28 weeks (OR 17.8, 95% CI 15.2-20.7) in the current pregnancy, compared to those who had prior low-transverse uterine incision. In a weighted model, prior vertical hysterotomy was associated with increased surgical morbidity in current CD compared to prior low-transverse hysterotomy (10.6% vs. 4.8%, OR 2.02, 95% CI 1.81-2.26), including hemorrhage (OR 1.99, 95% CI 1.74-2.27) and hysterectomy (OR 3.67, 95% CI 2.97-4.53). CONCLUSION: Prior vertical uterine incision at CD was associated with increased risk of placenta percreta, uterine rupture, particularly before labor, and adverse outcomes in the subsequent pregnancy.

Pregnancy characteristics and outcomes after bariatric surgery: national-level analysis in the United States.

BACKGROUND: Bariatric surgery is an effective surgical treatment for weight reduction in individuals with obesity. Pregnancy outcomes related to prior bariatric surgery are currently under active investigation. OBJECTIVE: To assess national-level trends, characteristics, and outcomes of pregnancy after bariatric surgery in the United States. SETTING: Retrospective cohort study queried the National Inpatient Sample. METHODS: The study population was 14,648,135 patients who had vaginal or cesarean delivery from January 2016 to December 2019. Exposure allocation was based on the history of bariatric surgery. The main outcomes were (1) trends and characteristics related to bariatric surgery, assessed with multivariable binary logistic regression model; and (2) Centers for Disease Control and Prevention-defined severe maternal morbidity, assessed by propensity score matching and generalized estimating equation. RESULTS: A total of 53,950 (.4%) patients had prior bariatric surgery. The number of patients with prior bariatric surgery increased from .3% to .5%, and this trend remained independent in multivariable analysis (P < .001). Patients who had bariatric surgery were also more likely to be older and have obesity, medical co-morbidities, fetal growth restriction, preterm birth, and cesarean delivery compared with those without bariatric surgery (all, P < .05). In a propensity score matched model, patients who had bariatric surgery were more likely to receive blood product transfusion (2.3% versus 1.6%; odds ratio = 1.45; 95% confidence interval, 1.19-1.77), but severe maternal morbidity other than blood product transfusion was comparable to those without (1.1% versus 1.4%; odds ratio = .80; 95% confidence interval, .63-1.02). CONCLUSION: There is a gradual increase of pregnancy after bariatric surgery in recent years in the United States.

Dynamics and outcomes of binary collisions of equi-diameter picolitre droplets with identical viscosities.

The dynamics of binary collisions of equi-diameter picolitre droplets with identical viscosities, varying impact speeds and impact angles have been investigated experimentally and compared to collision outcome prediction models. Collisions between pairs of pure water droplets with a viscosity of 0.89 mPa s and pairs of aqueous-sucrose (40% w/w) droplets with a viscosity of 5.17 mPa s were examined. The colliding droplets were ∼38 µm in diameter, which is around ten times smaller than those previously investigated when examining the effect of viscosity on the outcome of binary droplet collisions. Varying the impact speed and angle resulted in different collision outcomes, including coalescence, reflexive separation and stretching separation. The collision outcomes were plotted on two viscosity dependent regime maps. The regime boundaries are generally in agreement with earlier literature for both high and low viscosity cases. The agreement between experiment and theory, for both fluids, gives more confidence in the models tested here to predict collision outcomes for droplets of this size and these viscosities.

Mental/behavioural health and educational outcomes of grandchildren raised by custodial grandparents: A mixed methods systematic review.

Grandparents caring for grandchildren has increased globally in the past two decades, but we have a limited understanding of its effects on custodial grandchildren's mental/behavioural health and educational outcomes. This mixed methods systematic review aims to synthesise mental/behavioural health and educational outcomes of custodial grandchildren within custodial grandparent-headed families and with comparison to other types of household structure and further examine factors associated with these outcomes. A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. We searched ERIC, Family Studies Abstracts, PsycINFO, PubMed, Scopus, Social Work Abstract and SocINDEX in March 2021 and screened 14,515 articles, which resulted in the inclusion of 42 studies, including 33 quantitative, seven qualitative and two mixed methods studies. The quality of included studies was assessed. This review covered 10 countries, yet most studies revealed that grandchildren raised by grandparents had adverse mental/behavioural health and educational outcomes compared to their peers raised by biological parents. This review further identified multi-level factors contributing to custodial grandchildren's adverse outcomes. Methodological limitations and implications for future practice and research were discussed.

Comparing aerosol number and mass exhalation rates from children and adults during breathing, speaking and singing.

Aerosol particles of respirable size are exhaled when individuals breathe, speak and sing and can transmit respiratory pathogens between infected and susceptible individuals. The COVID-19 pandemic has brought into focus the need to improve the quantification of the particle number and mass exhalation rates as one route to provide estimates of viral shedding and the potential risk of transmission of viruses. Most previous studies have reported the number and mass concentrations of aerosol particles in an exhaled plume. We provide a robust assessment of the absolute particle number and mass exhalation rates from measurements of minute ventilation using a non-invasive Vyntus Hans Rudolf mask kit with straps housing a rotating vane spirometer along with measurements of the exhaled particle number concentrations and size distributions. Specifically, we report comparisons of the number and mass exhalation rates for children (12-14 years old) and adults (19-72 years old) when breathing, speaking and singing, which indicate that child and adult cohorts generate similar amounts of aerosol when performing the same activity. Mass exhalation rates are typically 0.002-0.02 ng s-1 from breathing, 0.07-0.2 ng s-1 from speaking (at 70-80 dBA) and 0.1-0.7 ng s-1 from singing (at 70-80 dBA). The aerosol exhalation rate increases with increasing sound volume for both children and adults when both speaking and singing.

Collaborative conversations during the time of COVID-19: Building a "meta"-learning community.

PROBLEM: COVID-19 created new research, clinical, educational, and personal challenges, while simultaneously separating work teams who were under work-from-home restrictions. Addressing these challenges required new forms of collaborative groups. APPROACH: To support the department community and the rapid sharing of new research, educational, clinical, and personal efforts, a Core Team from the Department of Learning Health Sciences at the University of Michigan developed a meeting series called the COVID Conversations. This Experience Report shares the organizational structure of the COVID Conversations, proposes a comparison to traditional Learning Communities, and reports the results of a questionnaire that gathered details about department members' COVID-related activities. OUTCOMES: We identify and describe salient similarities and differences between the COVID Conversations and the characteristics of Learning Communities. We also developed and piloted a taxonomy for characterizing LHS research projects that may be further developed for use in Learning Community planning, in conjunction with other maturity grids and ontologies. We propose the term "Meta-Learning Community" to describe the structure and function of the COVID Conversations. NEXT STEPS: In academic medicine, remote work, telemedicine, and virtual learning may be here to stay. The COVID Conversations constitute a distinct and innovative form of collaborative work in which separate teams addressing distinct goals, yet sharing a common passion to tackle the issues brought by the pandemic, are able to share experiences and learn from one other. The challenges of COVID-19 have made evident the need for multiple forms of organizing teamwork, and our study contributes the notion of a "Meta"-Learning Community as a new form of collaborative work.

Racial and ethnic disparity in characteristics and outcomes of women with placenta accreta spectrum: a comparative study.

Placenta accreta spectrum (PAS) refers to the spectrum of diagnoses involving abnormally and morbidly adherent trophoblastic tissue to the gravid uterus. These disorders are associated with significant maternal morbidity and mortality. While race/ethnicity is known to impact pregnancy outcomes, racial disparities have not been previously examined in women with PAS. The objective of current study was to compare patient characteristics and perioperative outcomes of women with PAS who underwent cesarean delivery across race/ethnicity. This is a comparative study that retrospectively queried the National Inpatient Sample, a hospital-based inpatient database in the USA. The study cohort was women diagnosed with PAS who underwent cesarean delivery from 10/2015 to 12/2018. The exposure group was race/ethnicity. Main outcomes were (i) patient/pregnancy characteristics and (ii) surgical morbidity for cesarean delivery, assessed in multivariable analysis. A total of 10,535 women comprised the study cohort (White n = 5,230 [49.6%], Black n = 2,045 [19.4%], Hispanic n = 2,540 [24.1%], and Asian n = 720 [6.8%]). Patient demographics, pregnancy characteristics, and hospital factors for the non-White groups significantly differed compared to the White group. Older age, obesity, diabetes, placenta previa, percreta, non-elective surgery, lower median household income, and Medicaid particularly represented the non-White groups. When perioperative outcomes were compared, non-White women were more likely to have any measured complications, hemorrhage/transfusion, and shock/coagulopathy compared to White women. Various sensitivity analyses redemonstrated the main cohort results. In conclusion, this study suggests that there were significant disparities in patient characteristics and outcomes of women with PAS across race/ethnicity.

Impact of Pharmacist Intervention in Response to Automated Molecular Diagnostic Tests of Blood Culture Results.

BACKGROUND: Rapid molecular diagnostic tests can aid in deescalating antimicrobial therapy prior to final culture and susceptibility reports. OBJECTIVE: The purpose of this study was to determine whether a new workflow that incorporated pharmacist review of these results reduced time to change in antimicrobial therapy. METHODS: This retrospective study analyzed pre- and post-implementation of pharmacist review of positive blood cultures analyzed by rapid diagnostics with clinical recommendations paged to providers. Patients 18 years of age or older initiated on empiric antibiotics were included. The primary outcome was the time to change to targeted antimicrobials. Other outcomes evaluated were rates of Clostridioides difficile (C difficile) infection, inpatient mortality, and intensive care unit and hospital lengths of stay. RESULTS: A total of 199 patients were included, with 98 and 101 patients in the pre- and post-implementation groups, respectively. The median time to change to targeted antimicrobials was significantly reduced with pharmacist intervention from 18.35 to 8.43 hours (P = 0.042). The groups had similar rates of C difficile infection (1% vs 0%, P = 0.492) and mortality (7.1% vs 5%, P = 0.564). The post-group also had significant reductions in antibiotic days of therapy (10.5 vs 9 days, P = 0.014) and intensive care unit length of stay (3.04 vs 1.44 days, P = 0.046). Median hospital length of stay was similar between the pre- and post-groups (8.5 vs 8 days, P = 0.106), respectively. CONCLUSION: Incorporating pharmacist review of rapid molecular results of blood cultures decreased time to change to targeted antimicrobials and reduced inpatient antibiotic days of therapy.

Nanophotonic Approaches for Chirality Sensing.

Chiral nanophotonic materials are promising candidates for biosensing applications because they focus light into nanometer dimensions, increasing their sensitivity to the molecular signatures of their surroundings. Recent advances in nanomaterial-enhanced chirality sensing provide detection limits as low as attomolar concentrations (10-18 M) for biomolecules and are relevant to the pharmaceutical industry, forensic drug testing, and medical applications that require high sensitivity. Here, we review the development of chiral nanomaterials and their application for detecting biomolecules, supramolecular structures, and other environmental stimuli. We discuss superchiral near-field generation in both dielectric and plasmonic metamaterials that are composed of chiral or achiral nanostructure arrays. These materials are also applicable for enhancing chiroptical signals from biomolecules. We review the plasmon-coupled circular dichroism mechanism observed for plasmonic nanoparticles and discuss how hotspot-enhanced plasmon-coupled circular dichroism applies to biosensing. We then review single-particle spectroscopic methods for achieving the ultimate goal of single-molecule chirality sensing. Finally, we discuss future outlooks of nanophotonic chiral systems.

Trends, characteristics, and outcomes of placenta accreta spectrum: a national study in the United States.

BACKGROUND: Although an infrequent occurrence, the placenta can adhere abnormally to the gravid uterus leading to significantly high maternal morbidity and mortality during cesarean delivery. Contemporary national statistics related to a morbidly adherent placenta, referred to as placenta accreta spectrum, are needed. OBJECTIVE: This study aimed to examine national trends, characteristics, and perioperative outcomes of women who underwent cesarean delivery for placenta accreta spectrum in the United States. STUDY DESIGN: This is a population-based retrospective, observational study querying the National Inpatient Sample. The study cohort included women who underwent cesarean delivery from October 2015 to December 2017 and had a diagnosis of placenta accreta spectrum. The main outcome measures were patient characteristics and surgical outcomes related to placenta accreta spectrum assessed by the generalized estimating equation on multivariable analysis. The temporal trend of placenta accreta spectrum was also assessed by linear segmented regression with log transformation. RESULTS: Of 2,727,477 cases who underwent cesarean delivery during the study period, 8030 (0.29%) had the diagnosis of placenta accreta spectrum. Placenta accreta was the most common diagnosis (n=6205, 0.23%), followed by percreta (n=1060, 0.04%) and increta (n=765, 0.03%). The number of placenta accreta spectrum cases increased by 2.1% every quarter year from 0.27% to 0.32% (P=.004). On multivariable analysis, (1) patient demographics (older age, tobacco use, recent diagnosis, higher comorbidity, and use of assisted reproductive technology), (2) pregnancy characteristics (placenta previa, previous cesarean delivery, breech presentation, and grand multiparity), and (3) hospital factors (urban teaching center and large bed capacity hospital) represented the independent characteristics related to placenta accreta spectrum (all, P<.05). The median gestational age at cesarean delivery was 36 weeks for placenta accreta and 34 weeks for both placenta increta and percreta vs 39 weeks for non-placenta accreta spectrum cases (P<.001). On multivariable analysis, cesarean delivery complicated by placenta accreta spectrum was associated with increased risk of any surgical morbidities (78.3% vs 10.6%), Centers for Disease Control and Prevention-defined severe maternal morbidity (60.3% vs 3.1%), hemorrhage (54.1% vs 3.9%), coagulopathy (5.3% vs 0.3%), shock (5.0% vs 0.1%), urinary tract injury (8.3% vs 0.2%), and death (0.25% vs 0.01%) compared with cesarean delivery without placenta accreta spectrum. When further analyzed by subtype, cesarean delivery for placenta increta and percreta was associated with higher likelihood of hysterectomy (0.4% for non-placenta accreta spectrum, 45.8% for accreta, 82.4% for increta, 78.3% for percreta; P<.001) and urinary tract injury (0.2% for non-placenta accreta spectrum, 5.2% for accreta, 11.8% for increta, 24.5% for percreta; P<.001). Moreover, women in the placenta increta and percreta groups had markedly increased risks of surgical mortality compared with those without placenta accreta spectrum (increta, odds ratio, 19.9; and percreta, odds ratio, 32.1). CONCLUSION: Patient characteristics and outcomes differ across the placenta accreta spectrum subtypes, and women with placenta increta and percreta have considerably high surgical morbidity and mortality risks. Notably, 1 in 313 women undergoing cesarean delivery had a diagnosis of placenta accreta spectrum by the end of 2017, and the incidence seems to be higher than reported in previous studies.

Development of coupled patient care experience courses to enhance patient care skills in the ambulatory and acute care settings.

BACKGROUND AND PURPOSE: Providing opportunities to allow pharmacy students to apply clinical skills is essential to ensure that they are comfortable and competent to perform these skills during advanced pharmacy practice experiences (APPEs) and in practice. We describe unique coupled courses that require students to apply clinical skills during real patient encounters and simulation activities in the ambulatory and acute care setting to ensure that they are ready for APPEs. EDUCATIONAL ACTIVITY AND SETTING: New required courses were developed at West Virginia University School of Pharmacy that focused on teaching and reinforcing patient care skills in the ambulatory and acute care settings. Both courses were designed to provide students with multiple opportunities to offer supervised patient care and to become more comfortable and confident in their patient care skills. FINDINGS: The coupled courses were well-received by students. Feedback indicated that students felt more comfortable in these patient care settings and in performing patient care activities as a result of these courses. SUMMARY: These coupled courses offered multiple opportunities for students to practice patient care skills and gain valuable experience participating in activities that increased their confidence and competence at being integral members of the healthcare team. The interactions with real patients, simulated patient scenarios, standardized patients, and other members of the healthcare team helped students advance communication skills, clinical skills, and ability to identify and resolve medication-related problems in preparation for APPEs.

Polarized evanescent waves reveal trochoidal dichroism.

Matter's sensitivity to light polarization is characterized by linear and circular polarization effects, corresponding to the system's anisotropy and handedness, respectively. Recent investigations into the near-field properties of evanescent waves have revealed polarization states with out-of-phase transverse and longitudinal oscillations, resulting in trochoidal, or cartwheeling, field motion. Here, we demonstrate matter's inherent sensitivity to the direction of the trochoidal field and name this property trochoidal dichroism. We observe trochoidal dichroism in the differential excitation of bonding and antibonding plasmon modes for a system composed of two coupled dipole scatterers. Trochoidal dichroism constitutes the observation of a geometric basis for polarization sensitivity that fundamentally differs from linear and circular dichroism. It could also be used to characterize molecular systems, such as certain light-harvesting antennas, with cartwheeling charge motion upon excitation.

Women's Experiences After Ovarian Cancer Surgery: Distress, Uncertainty, and the Need for Occupational Therapy.

IMPORTANCE: Despite the growing literature on the association of functional, physical, and quality-of-life (QOL) deficits with poor postoperative outcomes, there is a gap in the literature identifying women's occupational performance needs after ovarian cancer surgery. OBJECTIVE: To describe the experiences of women hospitalized after ovarian cancer surgery to identify potential areas for intervention. Goals were to (1) identify functional needs and limitations at time of discharge as measured by the typical acute care occupational therapy evaluation and semistructured interview and (2) understand the women's perspectives of their needs for occupational therapy and a safe return to home. DESIGN: Single-arm, cross-sectional descriptive study. Mixed-methods data collection and analysis. SETTING: Academic cancer center. PARTICIPANTS: Women with ovarian cancer (N = 11) who had completed surgery. INTERVENTION: Semistructured interviews and patient-reported outcome measures (PROMs) completed postsurgery. OUTCOMES AND MEASURES: PROMs included the National Comprehensive Cancer Network (NCCN) Distress Thermometer and Problem List, the PROMIS® Global Physical Health (GPH) and Global Mental Health (GMH) scales, and the Possibilities for Activity Scale-Women (PActS-W). RESULTS: The mean NCCN Distress score was 6.0 (standard deviation [SD] = 3.1, with the top three concerns being pain (80%), worry (80%), and fatigue (78%). Mean GPH and GMH T scores were 38.0 (SD = 8.8) and 48.2 (SD = 8.4), respectively. Women scored a mean of 39.2 (SD = 11.2, range = 26-58) on the PActS-W. Thematic analyses found that the women were uncertain about potential functional limitations and significantly distressed. CONCLUSION AND RELEVANCE: Women with ovarian cancer experienced high levels of uncertainty and distress after surgery. Integrating in-home or community-based occupational therapy into routine care could decrease functional distress and uncertainty and help women manage concerns related to pain, worry, and fatigue. WHAT THIS ARTICLE ADDS: This study suggests that occupational therapy evaluation and intervention are needed to decrease distress and improve QOL of women upon discharge after ovarian cancer surgery.

Quantitative Analysis of Nanorod Aggregation and Morphology from Scanning Electron Micrographs Using SEMseg.

General methods to achieve better physical insight about nanoparticle aggregation and assembly are needed because of the potential role of aggregation in a wide range of materials, environmental, and biological outcomes. Scanning electron microscopy (SEM) is fast and affordable compared to transmission electron microscopy, but SEM micrographs lack contrast and resolution due to lower beam energy, topographic contrast, edge effects, and charging. We present a new segmentation algorithm called SEMseg that is robust to the challenges inherent in SEM micrograph analysis and demonstrate its utility for analyzing gold (Au) nanorod aggregates. SEMseg not only supports nanoparticle size analysis for dispersed nanoparticles, but also discriminates between nanoparticles within an aggregate. We compare our algorithm to those incorporated into the commonly used software ImageJ and demonstrate improved segmentation of aggregate structures. New physical insight about aggregation is demonstrated by the introduction of an order parameter describing side-by-side structure in nanoparticle aggregates. We also present the segmentation and fitting algorithms included in SEMseg within a user-friendly graphical user interface. The resulting code is provided with an open-source interface to provide quantitative image processing tools for researchers to characterize both dispersed nanoparticles and nanoparticle assemblies in SEM micrographs with high throughput.

DNA-Enabled Chiral Gold Nanoparticle-Chromophore Hybrid Structure with Resonant Plasmon-Exciton Coupling Gives Unusual and Strong Circular Dichroism.

Circular dichroism (CD) from hybrid complexes of plasmonic nanostructures and chiral molecules has recently attracted significant interest. However, the hierarchical chiral self-assembly of molecules on surfaces of metal nanostructures has remained challenging. As a result, a deep understanding of plasmon-exciton coupling between surface plasmons and chiral collective molecular excitations has not been achieved. In particular, the critical impact of resonant plasmon-exciton coupling within the hybrid is unclear. Here, we employed DNA-templated strategies to control the chiral self-assembly of achiral chromophores with rationally tuned exciton transitions on gold nanosphere (AuNP) or gold nanorod (AuNR) surfaces. Unlike many previous chiral plasmonic hybrids utilizing chiral biomolecules with CD signals in the UV range, we designed structures with the chiral excitonic resonances at visible wavelengths. The constructed hybrid complexes displayed strong chiroptical activity that depends on the spectral overlap between the chiral collective molecular excitations and the plasmon resonances. We find that when spectral overlap is optimized, the molecular CD signal originating from the chiral self-assemblies of chromophores was strongly enhanced (maximum enhancement of nearly an order of magnitude) and a plasmonic CD signal was induced. Surprisingly, the sign of the molecular CD was reversed despite different self-assembly mechanisms of the Au nanoparticle-chromophore hybrids. Our results provide new insight into plasmonic CD enhancements and will inspire further studies on chiral light-matter interactions in strongly coupled plasmonic-excitonic systems.

Unraveling the origin of chirality from plasmonic nanoparticle-protein complexes.

Plasmon-coupled circular dichroism has emerged as a promising approach for ultrasensitive detection of biomolecular conformations through coupling between molecular chirality and surface plasmons. Chiral nanoparticle assemblies without chiral molecules present also have large optical activities. We apply single-particle circular differential scattering spectroscopy coupled with electron imaging and simulations to identify both structural chirality of plasmonic aggregates and plasmon-coupled circular dichroism induced by chiral proteins. We establish that both chiral aggregates and just a few proteins in interparticle gaps of achiral assemblies are responsible for the ensemble signal, but single nanoparticles do not contribute. We furthermore find that the protein plays two roles: It transfers chirality to both chiral and achiral plasmonic substrates, and it is also responsible for the chiral three-dimensional assembly of nanorods. Understanding these underlying factors paves the way toward sensing the chirality of single biomolecules.