Second Time's the Charm? Assessing the Sensitivity and Yield of Inpatient Diagnostic Algorithms for Pulmonary Tuberculosis in a Low-Prevalence Setting.

Background: For persons with suspected pulmonary tuberculosis, the guidelines of the Centers for Disease Control and Prevention recommend collecting 3 respiratory specimens 8 to 24 hours apart for acid-fast bacilli (AFB) smear and culture, in addition to 1 nucleic acid amplification test (NAAT). However, data supporting this approach are limited. Our objective was to estimate the performance of 1, 2, or 3 AFB smears with or without NAATs to detect pulmonary tuberculosis in a low-prevalence setting. Methods: We conducted a retrospective study of hospitalized persons at 8 Massachusetts acute care facilities who underwent mycobacterial culture on 1 or more respiratory specimens between July 2016 and December 2022. We evaluated percentage positivity and yield on serial AFB smears and NAATs among people with growth of Mycobacterium tuberculosis on mycobacterial cultures. Results: Among 104 participants with culture-confirmed pulmonary tuberculosis, the first AFB smear was positive in 41 cases (39%). A second AFB smear was positive in 11 (22%) of the 49 cases in which it was performed. No third AFB smears were positive following 2 initial negative smears. Of 52 smear-negative cases, 36 had a NAAT performed, leading to 23 additional diagnoses. Overall sensitivity to detect tuberculosis prior to culture positivity was higher in any strategy involving 1 or 2 NAATs (74%-79%), even without AFB smears, as compared with 3 smears alone (60%). Conclusions: Tuberculosis diagnostic testing with 2 AFB smears offered the same yield as 3 AFB smears while potentially reducing laboratory burden and duration of airborne infection isolation. Use of 1 or 2 NAATs increased sensitivity to detect culture-positive pulmonary tuberculosis when added to AFB smear-based diagnostic testing alone.

Separating the rash from the chaff: novel clinical decision support deployed during the mpox outbreak.

A clinical decision support system, EvalMpox, was developed to apply person under investigation (PUI) criteria for patients presenting with rash and to recommend testing for PUIs. Of 668 patients evaluated, an EvalMpox recommendation for testing had a positive predictive value of 35% and a negative predictive value of 99% for a positive mpox test.

The application of antimicrobial stewardship knowledge to nursing practice: A national survey of United Kingdom pre-registration nursing students.

AIM: To assess student nurses understanding and skills in the application of antimicrobial stewardship knowledge to practice. DESIGN: Quantitative. METHODS: Cross-sectional survey. RESULTS: Five hundred and twenty three student nurses responded across 23 UK universities. Although students felt prepared in competencies in infection prevention and control, patient-centred care and interprofessional collaborative practice, they felt less prepared in competencies in which microbiological knowledge, prescribing and its effect on antimicrobial stewardship is required. Problem-based learning, activities in the clinical setting and face-to-face teaching were identified as the preferred modes of education delivery. Those who had shared antimicrobial stewardship teaching with students from other professions reported the benefits to include a broader understanding of antimicrobial stewardship, an understanding of the roles of others in antimicrobial stewardship and improved interprofessional working. CONCLUSION: There are gaps in student nurses' knowledge of the basic sciences associated with the antimicrobial stewardship activities in which nurses are involved, and a need to strengthen knowledge in pre-registration nurse education programmes pertaining to antimicrobial management, specifically microbiology and antimicrobial regimes and effects on antimicrobial stewardship. Infection prevention and control, patient-centred care and interprofessional collaborative practice are areas of antimicrobial stewardship in which student nurses feel prepared. Interprofessional education would help nurses and other members of the antimicrobial stewardship team clarify the role nurses can play in antimicrobial stewardship and therefore maximize their contribution to antimicrobial stewardship and antimicrobial management. IMPLICATIONS FOR THE PROFESSION: There is a need to strengthen knowledge from the basic sciences, specifically pertaining to antimicrobial management, in pre-registration nurse education programmes. PATIENT OR PUBLIC CONTRIBUTION: No patient or public contribution. IMPACT: What Problem Did the Study Address? Nurses must protect health through understanding and applying antimicrobial stewardship knowledge and skills (Nursing and Midwifery Council 2018); however, there is no research available that has investigated nurses understanding and skills of the basic sciences associated with the antimicrobial stewardship activities in which they are involved. What Were the Main Findings? There are gaps in student nurses' knowledge of the basic sciences (specifically microbiology and prescribing) associated with the antimicrobial stewardship activities in which nurses are involved. Problem-based learning, and activities in the clinical setting, were reported as useful teaching methods, whereas online learning, was seen as less useful. Where and on Whom Will the Research Have an Impact? Pre-registration nurse education programmes. REPORTING METHOD: The relevant reporting method has been adhered to, that is, STROBE.

The Resilience of Final-Year Pharmacy Students and Aspects of the Course They Found to Be Resilience-Building.

Background: This work aimed to investigate final year pharmacy students' resilience (as determined by the CD-RISC-25 tool), whether students considered certain aspects of the course to be resilience-building, and the role of the university in developing this attribute. Methods: Following ethical approval and an invitation to participate, data were collected from consenting students at Queen's University Belfast via a pre-piloted paper-based questionnaire. Descriptive statistics were performed. To ascertain significant differences (p < 0.05) by gender, the Welch Two Sample t-test was used for the CD-RISC-25 mean scores and the Mann-Whitney U Test and Chi-squared test for Section B data. Results: The response rate was 80.61% (79/98). The mean CD-RISC-25 score for males was higher (not significantly) than the female mean score (70.39 versus 67.18, p = 0.2355, possible score range 0−100). While 93.67% (74/79) considered the School has a responsibility to develop resilience, <20.00% availed of the free resilience building events. Activities deemed to help build resilience included being able to make mistakes in a safe environment and needing to achieve a high grade to pass assessments. Conclusions: Resilience levels among future pharmacists at Queen's University Belfast should be improved going forward. A strategy, developed in light of conducting this research (from one institution), will now be implemented to enhance the curriculum with regard to resilience building opportunities.

Challenges and advances in optical 3D mesoscale imaging.

Optical mesoscale imaging is a rapidly developing field that allows the visualisation of larger samples than is possible with standard light microscopy, and fills a gap between cell and organism resolution. It spans from advanced fluorescence imaging of micrometric cell clusters to centimetre-size complete organisms. However, with larger volume specimens, new problems arise. Imaging deeper into tissues at high resolution poses challenges ranging from optical distortions to shadowing from opaque structures. This manuscript discusses the latest developments in mesoscale imaging and highlights limitations, namely labelling, clearing, absorption, scattering, and also sample handling. We then focus on approaches that seek to turn mesoscale imaging into a more quantitative technique, analogous to quantitative tomography in medical imaging, highlighting a future role for digital and physical phantoms as well as artificial intelligence.

This review discusses the state of the art of an emerging field called mesoscale imaging. Mesoscale imaging refers to the trend towards imaging ever-larger samples that exceed the classic microscopy domain and is also referred to as 'mesoscopic imaging'. In optical imaging, this refers to objects between the microscopic and macroscopic scale that are imaged with subcellular resolution; in practice, this implies the imaging of objects from millimetre up to cm size with µm or nm resolution. As such, the mesoscopy field spans the boundary between classic 'biological' imaging and preclinical 'biomedical' imaging, typically utilising lower magnification objective lenses with a bigger field of view. We discuss the types of samples currently imaged with examples, and highlight how this type of imaging fills the gap between microscopic and macroscopic imaging, allowing further insight into the organisation of tissues in an organism. We also discuss the challenges of imaging such large samples, from sample handling to labelling and optical phenomena that stand in the way of quantitative imaging. Finally, we put the current state of the art into context within the neighbouring fields and outline future developments, such as the use of 'phantom' test samples and artificial intelligence for image analysis that will underpin the quality of mesoscale imaging.

Future Pharmacists' Opinions on the Facilitation of Self-Care with Over-the-Counter Products and Whether This Should Remain a Core Role.

BACKGROUND: The aim was to investigate pharmacy students' views on the role of the pharmacist in facilitating self-care with over-the-counter (OTC) medicines, particularly in light of new roles, and establish personal practice. METHODS: Final year pharmacy students at Queen's University Belfast were invited to participate. Data were collected via a pre-piloted questionnaire, distributed at a compulsory class (only non-identifiable data were requested). Descriptive statistics were performed, and non-parametric tests were employed for inferential statistical analysis (responses by gender). RESULTS: The response rate was 87.6% (78/89); 34.6% (27/78) males and 65.4% (51/78) females. Over a third [34.6% (27/78)] reported using OTC medicines about once a month. All appreciated the importance of an evidence-based approach to optimize patient care. Most [(96.2% (75/78)] deemed OTC consultations should remain a fundamental responsibility of pharmacists and 69.2% (54/78) thought OTC consultations have the potential to be as complex as independent pharmacist prescribing. Females felt more confident recommending OTC emergency contraception than males (p = 0.002 for levonorgestrel and p = 0.011 for ulipristal acetate). Many [61.5% (48/78)] considered more medicines should not be deregulated from prescription-only status. CONCLUSIONS: Data from this single institution suggests that enabling self-medication is an important part of practice but there were confidence issues around deregulations.

Development of a high-level light-activated disinfectant for hard surfaces and medical devices.

BACKGROUND: Bacterial spores are an important consideration in healthcare decontamination, with cross-contamination highlighted as a major route of transmission due to their persistent nature. Their containment is extremely difficult due to the toxicity and cost of first-line sporicides. METHODS: Susceptibility of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli to phenothiazinium photosensitizers and cationic surfactants under white- or red-light irradiation was assessed by determination of minimum inhibitory concentrations, minimum bactericidal concentrations and time-kill assays. B. subtilis spore eradication was assessed via time-kill assays, with and without nutrient and non-nutrient germinant supplementation of photosensitizer, surfactant and photosensitizer-surfactant solutions in the presence and absence of light. RESULTS: Under red-light irradiation, >5-log10 colony-forming units/mL reduction of vegetative bacteria was achieved within 10 min with toluidine blue O (TBO) and methylene blue (MB). Cationic surfactant addition did not significantly enhance spore eradication by photosensitizers (P>0.05). However, addition of a nutrient germinant mixture to TBO achieved a 6-log10 reduction after 20 min of irradiation, while providing 1-2 log10 improvement in spore eradication for MB and pyronin Y. CONCLUSIONS: Light-activated photosensitizer solutions in the presence of surfactants and germination-promoting agents provide a highly effective method to eradicate dormant and vegetative bacteria. These solutions could provide a useful alternative to traditional chemical agents used for high-level decontamination and infection control within health care.

Veganism: Are future pharmacists ready to provide advice?

INTRODUCTION: In addition to advising about diets, nutritional deficiencies, and supplements, pharmacists should be confident discussing medicine-related issues that may arise from people adopting veganism, including checking about animal-derived pharmaceutical product excipients, formulation processes, and determining whether vegan-friendly alternatives exist. Thus, this study aimed to investigate pharmacy students' knowledge and views about veganism. METHODS: Given veganism's increasing popularity and relevance to pharmacy practice, students enrolled in their last year of the undergraduate master of pharmacy degree program at Queen's University Belfast participated in this voluntary study. The questionnaire was given out at an obligatory workshop (only non-identifiable data were requested). Students were scored on veganism knowledge (22 true/false statements) with other analysis about views being largely descriptive in nature. RESULTS: Ninety-two out of 101 (91.1%) completed the questionnaire. Only one reporting being vegan. Mean knowledge score (possible range of 0-22) was 16.59 (±2.43). Only 37% (34/92) reported feeling confident discussing veganism with patients or other healthcare professionals and 40.2% (37/92) deemed they could establish whether a medical product is vegan-friendly. A minority (4.3%) considered they had received adequate training on veganism. A greater proportion of males than females considered that vegans are too forceful with their beliefs (74.2% vs. 51.7%). CONCLUSIONS: This study presents the first description of pharmacy students' knowledge and opinions on veganism (from a single institution only). The reported gap in educational provision and lack of confidence needs to be investigated and addressed to enhance patient-centered care.

Metabolite profile comparisons between ascending and descending colon tissue in healthy adults.

BACKGROUND: Obesity is a risk factor for colorectal cancer, yet metabolic distinctions between healthy right and left colon tissue, before cancer is diagnosed, remains largely unknown. This study compared right-ascending and left-descending colon tissue metabolomes to identify differences from the stool metabolome in normal weight, overweight, and obese adults. AIM: To examine right and left colon tissue metabolites according to body mass index that may serve as mechanistic targets for interventions and biomarkers for colon cancer risk. METHODS: Global, non-targeted metabolomics was applied to assess right-ascending and left-descending colon tissue collected from healthy adults undergoing screening colonoscopies to test the hypothesis that BMI differentially impacts colon tissue metabolite profiles. The colon tissue and stool metabolome of healthy adults (n = 24) was analyzed for metabolite signatures and metabolic pathway networks implicated in progression of colorectal cancer. RESULTS: Ascending and descending colon contained 504 host, food, and microbiota-derived metabolites from normal weight, overweight and obese adults grouped according to body mass index. Amino acids, lipids, and nucleotides were among the chemical types that further differentiated from the stool metabolite profiles. Normal weight adults had 46 significantly different metabolites between ascending and descending colon tissue locations, whereas there were 37 metabolite differences in overweight and 28 metabolite differences for obese adults (P < 0.05). Obese adults had trimethylamine N-oxide, endocannabinoids and monoacylglycerols with different relative abundances identified between ascending and descending colon. Primary and secondary bile acids, vitamins, and fatty acids also showed marked relative abundance differences in colon tissue from overweight/obese adults. CONCLUSION: There were metabolite profile differences between right-ascending and left-descending colon tissue in healthy adults. Colon lipids and other metabolites in obese and overweight adults were distinguished from normal weight participants and associated with gut inflammation, nutrient absorption, and products of microbiota metabolism.

Direct Determination of Aerosol pH: Size-Resolved Measurements of Submicrometer and Supermicrometer Aqueous Particles.

Measuring the acidity of atmospheric aerosols is critical, as many key multiphase chemical reactions involving aerosols are highly pH-dependent. These reactions impact processes, such as secondary organic aerosol (SOA) formation, that impact climate and health. However, determining the pH of atmospheric particles, which have minute volumes (10-23-10-18 L), is an analytical challenge due to the nonconservative nature of the hydronium ion, particularly as most chemical aerosol measurements are made offline or under vacuum, where water can be lost and acid-base equilibria shifted. Because of these challenges, there have been no direct methods to probe atmospheric aerosol acidity, and pH has typically been determined by proxy/indirect methods, such as ion balance, or thermodynamic models. Herein, we present a novel and facile method for direct measurement of size-resolved aerosol acidity from pH 0 to 4.5 using quantitative colorimetric image processing of cellular phone images of (NH4)2SO4-H2SO4 aqueous aerosol particles impacted onto pH-indicator paper. A trend of increasing aerosol acidity with decreasing particle size was observed that is consistent with spectroscopic measurements of individual particle pH. These results indicate the potential for direct measurements of size-resolved atmospheric aerosol acidity, which is needed to improve fundamental understanding of pH-dependent atmospheric processes, such as SOA formation.

Extending surface enhanced Raman spectroscopy (SERS) of atmospheric aerosol particles to the accumulation mode (150-800 nm).

Due to their small size, measurements of the complex composition of atmospheric aerosol particles and their surfaces are analytically challenging. This is particularly true for microspectroscopic methods, where it can be difficult to optically identify individual particles smaller than the diffraction limit of visible light (∼350 nm) and measure their vibrational modes. Recently, surface enhanced Raman spectroscopy (SERS) has been applied to the study of aerosol particles, allowing for detection and characterization of previously undistinguishable vibrational modes. However, atmospheric particles analyzed via SERS have primarily been >1 µm to date, much larger than the diameter of the most abundant atmospheric aerosols (∼100 nm). To push SERS towards more relevant particle sizes, a simplified approach involving Ag foil substrates was developed. Both ambient particles and several laboratory-generated model aerosol systems (polystyrene latex spheres (PSLs), ammonium sulfate, and sodium nitrate) were investigated to determine SERS enhancements. SERS spectra of monodisperse, model aerosols between 400-800 nm were compared with non-SERS enhanced spectra, yielding average enhancement factors of 102 for both inorganic and organic vibrational modes. Additionally, SERS-enabled detection of 150 nm size-selected ambient particles represent the smallest individual aerosol particles analyzed by Raman microspectroscopy to date, and the first time atmospheric particles have been measured at sizes approaching the atmospheric number size distribution mode. SERS-enabled detection and identification of vibrational modes in smaller, more atmospherically-relevant particles has the potential to improve understanding of aerosol composition and surface properties, as well as their impact on heterogeneous and multiphase reactions involving aerosol surfaces.

Isoprene-Derived Organosulfates: Vibrational Mode Analysis by Raman Spectroscopy, Acidity-Dependent Spectral Modes, and Observation in Individual Atmospheric Particles.

Isoprene, the most abundant biogenic volatile organic compound (BVOC) in the atmosphere, and its low-volatility oxidation products lead to secondary organic aerosol (SOA) formation. Isoprene-derived organosulfates formed from reactions of isoprene oxidation products with sulfate in the particle phase are a significant component of SOA and can hydrolyze forming polyols. Despite characterization by mass spectrometry, their basic structural and spectroscopic properties remain poorly understood. Herein, Raman microspectroscopy and density functional theory (DFT) calculations (CAM-B3LYP level of theory) were combined to analyze the vibrational modes of key organosulfates, 3-methyltetrol sulfate esters (racemic mixture of two isomers), and racemic 2-methylglyceric acid sulfate ester, and hydrolysis products, 2-methyltetrols, and 2-methylglyceric acid. Two intense vibrational modes were identified, ν(RO-SO3) (846 ± 4 cm-1) and νs(SO3) (1065 ± 2 cm-1), along with a lower intensity δ(SO3) mode (586 ± 2 cm-1). For 2-methylglyceric acid and its sulfate esters, deprotonation of the carboxylic acid at pH values above the pKa decreased the carbonyl stretch frequency (1724 cm-1), while carboxylate modes grew in for νs(COO-) and νa(COO-) at 1413 and 1594 cm-1, respectively. The ν(RO-SO3) and νs(SO3) modes were observed in individual atmospheric particles and can be used in future studies of complex SOA mixtures to distinguish organosulfates from inorganic sulfate or hydrolysis products.

Aerosol Emissions from Great Lakes Harmful Algal Blooms.

In freshwater lakes, harmful algal blooms (HABs) of Cyanobacteria (blue-green algae) produce toxins that impact human health. However, little is known about the lake spray aerosol (LSA) produced from wave-breaking in freshwater HABs. In this study, LSA were produced in the laboratory from freshwater samples collected from Lake Michigan and Lake Erie during HAB and nonbloom conditions. The incorporation of biological material within the individual HAB-influenced LSA particles was examined by single-particle mass spectrometry, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and fluorescence microscopy. Freshwater with higher blue-green algae content produced higher number fractions of individual LSA particles that contained biological material, showing that organic molecules of biological origin are incorporated in LSA from HABs. The number fraction of individual LSA particles containing biological material also increased with particle diameter (greater than 0.5 µm), a size dependence that is consistent with previous studies of sea spray aerosol impacted by phytoplankton blooms. Similar to sea spray aerosol, organic carbon markers were most frequently observed in individual LSA particles less than 0.5 µm in diameter. Understanding the transfer of biological material from freshwater to the atmosphere via LSA is crucial for determining health and climate effects of HABs.

Inland Sea Spray Aerosol Transport and Incomplete Chloride Depletion: Varying Degrees of Reactive Processing Observed during SOAS.

Multiphase reactions involving sea spray aerosol (SSA) impact trace gas budgets in coastal regions by acting as a reservoir for oxidized nitrogen and sulfur species, as well as being a source of halogen gases (HCl, ClNO2, etc.). Whereas most studies of multiphase reactions on SSA have focused on marine environments, far less is known about SSA transported inland. Herein, single-particle measurements of SSA are reported at a site >320 km from the Gulf of Mexico, with transport times of 7-68 h. Samples were collected during the Southern Oxidant and Aerosol Study (SOAS) in June-July 2013 near Centreville, Alabama. SSA was observed in 93% of 42 time periods analyzed. During two marine air mass periods, SSA represented significant number fractions of particles in the accumulation (0.2-1.0 µm, 11%) and coarse (1.0-10.0 µm, 35%) modes. Chloride content of SSA particles ranged from full to partial depletion, with 24% of SSA particles containing chloride (mole fraction of Cl/Na ≥ 0.1, 90% chloride depletion). Both the frequent observation of SSA at an inland site and the range of chloride depletion observed suggest that SSA may represent an underappreciated inland sink for NOx/SO2 oxidation products and a source of halogen gases.

Spectroscopic Determination of Aerosol pH from Acid-Base Equilibria in Inorganic, Organic, and Mixed Systems.

Atmospheric aerosol acidity impacts key multiphase processes, such as acid-catalyzed reactions leading to secondary organic aerosol formation, which impact climate and human health. However, traditional indirect methods of estimating aerosol pH often disagree with thermodynamic model predictions, resulting in aerosol acidity still being poorly understood in the atmosphere. Herein, a recently developed method coupling Raman microspectroscopy with extended Debye-Hückel activity calculations to directly determine the acidity of individual particles (1-15 µm projected area diameter, average 6 µm) was applied to a range of atmospherically relevant inorganic and organic acid-base equilibria systems (HNO3/NO3-, HC2O4-/C2O42-, CH3COOH/CH3COO-, and HCO3-/CO32-) covering a broad pH range (-1 to 10), as well as an inorganic-organic mixture (sulfate-oxalate). Given the ionic strength of the inorganic solutions, the H+ activity, γ(H+), yielded lower values (0.68-0.75) than the organic and mixed systems (0.72-0.80). A consistent relationship between increasing peak broadness with decreasing pH was observed for acidic species, but not their conjugate bases. Greater insight into spectroscopic responses to acid-base equilibria for more complicated mixtures is still needed to understand the behavior of atmospheric aerosols.

Optimization of singlet oxygen production from photosensitizer-incorporated, medically relevant hydrogels.

Photodynamic therapy and photodynamic antimicrobial chemotherapy are widely used, but despite this, the relationships between fluence, wavelength of irradiation and singlet oxygen (1 O2 ) production are poorly understood. To establish the relationships between these factors in medically relevant materials, the effect of fluence on 1 O2 production from a tetrakis(4-N-methylpyridyl)porphyrin (TMPyP)-incorporated 2-hydroxyethyl methacrylate: methyl methacrylate: methacrylic acid (HEMA: MMA:MAA) copolymer, a total energy of 50.48 J/cm2 , was applied at varying illumination power, and times. 1 O2 production was characterized using anthracene-9,10-dipropionic acid, disodium salt (ADPA) using a recently described method. Using two light sources, a white LED array and a white halogen source, the LED array was found to produce less 1 O2 than the halogen source when the same power (over 500 - 600 nm) and time conditions were applied. Importantly, it showed that the longest wavelength Q band (590 nm) is primarily responsible for 1 O2 generation, and that a linear relationship exists between increasing power and time and the production of singlet oxygen. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 320-326, 2017.

Direct Measurement of pH in Individual Particles via Raman Microspectroscopy and Variation in Acidity with Relative Humidity.

Atmospheric aerosol acidity is an important characteristic of aqueous particles, which has been linked to the formation of secondary organic aerosol by catalyzing reactions of oxidized organic compounds that have partitioned to the particle phase. However, aerosol acidity is difficult to measure and traditionally estimated using indirect methods or assumptions based on composition. Ongoing disagreements between experiments and thermodynamic models of particle acidity necessitate improved fundamental understanding of pH and ion behavior in high ionic strength atmospheric particles. Herein, Raman microspectroscopy was used to determine the pH of individual particles (H2SO4+MgSO4) based on sulfate and bisulfate concentrations determined from νs(SO4(2-)) and νs(HSO4(-)), the acid dissociation constant, and activity coefficients from extended Debye-Hückel calculations. Shifts in pH and peak positions of νs(SO4(2-)) and νs(HSO4(-)) were observed as a function of relative humidity. These results indicate the potential for direct spectroscopic determination of pH in individual particles and the need to improve fundamental understanding of ion behavior in atmospheric particles.

Surface Enhanced Raman Spectroscopy Enables Observations of Previously Undetectable Secondary Organic Aerosol Components at the Individual Particle Level.

The first use of surface enhanced Raman spectroscopy (SERS) to detect trace organic and/or inorganic species in ambient atmospheric aerosol particles is presented. This new analytical method provides direct, spectroscopic detection of species present at attogram to femtogram levels in individual submicrometer atmospheric particles. An array of spectral features resulting from organic functional groups in secondary organic aerosol (SOA) material were observed in individual particles impacted on silver nanoparticle-coated substrates. The results demonstrate the complexity of organic and inorganic species in SOA formed by oxidation of biogenic volatile organic compounds (BVOCs) at the single particle level. While SOA composition is frequently assumed to be homogeneous between and within individual particles, substantial particle-to-particle variability in SOA composition and changes on scales <1 µm were observed. The observations obtained with this new method demonstrate the power of SERS to probe difficult to detect inter- and intraparticle variability in ambient SOA particles.

Photosensitisers - the progression from photodynamic therapy to anti-infective surfaces.

INTRODUCTION: The application of light as a stimulus in pharmaceutical systems and the associated ability to provide precise spatiotemporal control over location, wavelength and intensity, allowing ease of external control independent of environmental conditionals, has led to its increased use. Of particular note is the use of light with photosensitisers. AREAS COVERED: Photosensitisers are widely used in photodynamic therapy to cause a cidal effect towards cells on irradiation due to the generation of reactive oxygen species. These cidal effects have also been used to treat infectious diseases. The effects and benefits of photosensitisers in the treatment of such conditions are still being developed and further realised, with the design of novel delivery strategies. This review provides an overview of the realisation of the pharmaceutically relevant uses of photosensitisers, both in the context of current research and in terms of current clinical application, and looks to the future direction of research. EXPERT OPINION: Substantial advances have been and are being made in the use of photosensitisers. Of particular note are their antimicrobial applications, due to absence of resistance that is so frequently associated with conventional treatments. Their potency of action and the ability to immobilise to polymeric supports is opening a wide range of possibilities with great potential for use in healthcare infection prevention strategies.

Surface localisation of photosensitisers on intraocular lens biomaterials for prevention of infectious endophthalmitis and retinal protection.

Cataract surgery is one of the most commonly-practiced surgical procedures in Western medicine, and, while complications are rare, the most serious is infectious postoperative endophthalmitis. Bacteria may adhere to the implanted intraocular lens (IOL) and subsequent biofilm formation can lead to a chronic, difficult to treat infection. To date, no method to reduce the incidence of infectious endophthalmitis through bacterial elimination, while retaining optical transparency, has been reported. In this study we report a method to optimise the localisation of a cationic porphyrin at the surface of suitable acrylate copolymers, which is the first point of contact with potential pathogens. The porphyrin catalytically generates short-lived singlet oxygen, in the presence of visible light, which kills adherent bacteria indiscriminately. By restricting the photosensitiser to the surface of the biomaterial, reduction in optical transparency is minimised without affecting efficacy of singlet oxygen production. Hydrogel IOL biomaterials incorporating either methacrylic acid (MAA) or methyl methacrylate (MMA) co-monomers allow tuning of the hydrophobic and anionic properties to optimise the localisation of porphyrin. Physiochemical and antimicrobial properties of the materials have been characterised, giving candidate materials with self-generating, persistent anti-infective character against Gram-positive and Gram-negative organisms. Importantly, incorporation of porphyrin can also serve to protect the retina by filtering damaging shortwave visible light, due to the Soret absorption (λmax 430 nm).