Solution-processable near-infrared (NIR) photodetectors are urgently needed for a wide range of next-generation electronics, including sensors, optical communications and bioimaging. However, it is rare to find photodetectors with >300 kHz cut-off frequencies, especially in the NIR region, and many of the emerging inorganic materials explored are comprised of toxic elements, such as lead. Herein, solution-processed AgBiS2 photodetectors with high cut-off frequencies under both white light (>1 MHz) and NIR (approaching 500 kHz) illumination are developed. These high cut-off frequencies are due to the short transit distances of charge-carriers in the ultrathin photoactive layer of AgBiS2 photodetectors, which arise from the strong light absorption of this material, such that film thicknesses well below 120 nm are sufficient to absorb >65% of NIR to visible light. It is also revealed that ion migration plays a critical role in the photo-response speed of these devices, and its detrimental effects can be mitigated by finely tuning the thickness of the photoactive layer, which is important for achieving low dark current densities as well. These outstanding characteristics enable the realization of air-stable, real-time heartbeat sensors based on NIR AgBiS2 photodetectors, which strongly motivates their future integration in high-throughput systems.
Polarons exist when charges are injected into organic semiconductors due to their strong coupling with the lattice phonons, significantly affecting electronic charge-transport properties. Understanding the formation and (de)localization of polarons is therefore critical for further developing organic semiconductors as a future electronics platform. However, there are very few studies reported in this area. In particular, there is no direct in situ monitoring of polaron formation and identification of its dependence on molecular structure and impact on electrical properties, limiting further advancement in organic electronics. Herein, how a minor modification of side-chain density in thiophene-based conjugated polymers affects the polaron formation via electrochemical doping, changing the polymers' electrical response to the surrounding dielectric environment for gas sensing, is demonstrated. It is found that the reduction in side-chain density results in a multistep polaron formation, leading to an initial formation of localized polarons in thiophene units without side chains. Reduced side-chain density also allows the formation of a high density of polarons with fewer polymer structural changes. More numerous but more localized polarons generate a stronger analyte response but without the selectivity between polar and non-polar solvents, which is different from the more delocalized polarons that show clear selectivity. The results provide important molecular understanding and design rules for the polaron formation and its impact on electrical properties.
The dramatic improvement of the PCE (power conversion efficiency) of organic photovoltaic devices in the past few years has been driven by the development of new polymer donor materials and non-fullerene acceptors (NFAs). In the design of such materials synthetic scalability is often not considered, and hence complicated synthetic protocols are typical for high-performing materials. Here we report an approach to readily introduce a variety of solubilizing groups into a benzo[c][1,2,5]thiadiazole acceptor comonomer. This allowed for the ready preparation of a library of eleven donor polymers of varying side chains and comonomers, which facilitated a rapid screening of properties and photovoltaic device performance. Donor FO6-T emerged as the optimal material, exhibiting good solubility in chlorinated and non-chlorinated solvents and achieving 15.4% PCE with L8BO as the acceptor (15.2% with Y6) and good device stability. FO6-T was readily prepared on the gram scale, and synthetic complexity (SC) analysis highlighted FO6-T as an attractive donor polymer for potential large scale applications.
With the advent of nonfullerene acceptors (NFAs), organic photovoltaic (OPV) devices are now achieving high enough power conversion efficiencies (PCEs) for commercialization. However, these high performances rely on active layers processed from petroleum-based and toxic solvents, which are undesirable for mass manufacturing. Here, we demonstrate the use of biorenewable 2-methyltetrahydrofuran (2MeTHF) and cyclopentyl methyl ether (CPME) solvents to process donor: NFA-based OPVs with no additional additives in the active layer. Furthermore, to reduce the overall carbon footprint of the manufacturing cycle of the OPVs, we use polymeric donors that require a few synthetic steps for their synthesis, namely, PTQ10 and FO6-T, which are blended with the Y-series NFA Y12. High performance was achieved using 2MeTHF as the processing solvent, reaching PCEs of 14.5% and 11.4% for PTQ10:Y12 and FO6-T:Y12 blends, respectively. This work demonstrates the potential of using biorenewable solvents without additives for the processing of OPV active layers, opening the door to large-scale and green manufacturing of organic solar cells.
Emergent bioelectronic technologies are underpinned by the organic electrochemical transistor (OECT), which employs an electrolyte medium to modulate the conductivity of its organic semiconductor channel. Here we utilize postpolymerization modification (PPM) on a conjugated polymer backbone to directly introduce glycolated or anionic side chains via fluoride displacement. The resulting polymers demonstrated increased volumetric capacitances, with subdued swelling, compared to their parent polymer in p-type enhancement mode OECTs. This increase in capacitance was attributed to their modified side chain configurations enabling cationic charge compensation for thin film electrochemical oxidation, as deduced from electrochemical quartz crystal microbalance measurements. An overall improvement in OECT performance was recorded for the hybrid glycol/ionic polymer compared to the parent, owing to its low swelling and bimodal crystalline orientation as imaged by grazing-incidence wide-angle X-ray scattering, enabling its high charge mobility at 1.02 cm2·V-1·s-1. Compromised device performance was recorded for the fully glycolated derivative compared to the parent, which was linked to its limited face-on stacking, which hindered OECT charge mobility at 0.26 cm2·V-1·s-1, despite its high capacitance. These results highlight the effectiveness of anionic side chain attachment by PPM as a means of increasing the volumetric capacitance of p-type conjugated polymers for OECTs, while retaining solid-state macromolecular properties that facilitate hole transport.
Post-polymerisation functionalisation provides a facile and efficient way for the introduction of functional groups on the backbone of conjugated polymers. Using post-polymerisation functionalisation approaches, the polymer chain length is usually not affected, meaning that the resulting polymers only differ in their attached functional groups or side chains, which makes them particularly interesting for investigating the influence of the different groups on the polymer properties. For such functionalisations, highly efficient and selective reactions are needed to avoid the formation of complex mixtures or permanent defects in the polymer backbone. A variety of suitable synthetic approaches and reactions that fulfil these criteria have been identified and reported. In this review, a thorough overview is given of the post-polymerisation functionalisations reported to date, with the methods grouped based on the type of reaction used: cycloaddition, oxidation/reduction, nucleophilic aromatic substitution, or halogenation and subsequent cross-coupling reaction. Instead of modifications on the aliphatic side chains of the conjugated polymers, we focus on modifications directly on the conjugated backbones, as these have the most pronounced effect on the optical and electronic properties. Some of the discussed materials have been used in applications, ranging from solar cells to bioelectronics. By providing an overview of this versatile and expanding field for the first time, we showcase post-polymerisation functionalisation as an exciting pathway for the creation of new conjugated materials for a range of applications.
Electronics , Polymers , Polymers/chemistry , Polymerization
At hospital discharge, many older patients are at health and nutritional risk, indicating a requirement for ongoing care. We aim to evaluate the effects of comprehensive individualized care by geriatric-experienced care professionals, the so-called "pathfinders", on nutritional status (NS) of older patients after discharge. A total of 244 patients (median age 81.0 years) without major cognitive impairment were randomized to Intervention Group (IG: 123) or Control Group (CG: 121) for a 12-month intervention, with up to 7 home visits and 11 phone calls. The comprehensive individualized care contained nutritional advice, when required. The intervention effect after three (T3m) and 12 (T12m) months on change in MNA-SF (Mini Nutritional Assessment-Short Form) and BMI was evaluated by Univariate General Linear Model (ANOVA), adjusted for age, sex, living situation, and activities of daily living. At baseline, mean MNA-SF did not differ between IG and CG (10.7 ± 2.6 vs. 11.2 ± 2.5, p = 0.148); however, mean BMI was significantly lower in IG compared to CG (27.2 ± 4.7 vs. 28.8 ± 4.8 kg/m2, p = 0.012). At T3m, mean change did not differ significantly between the groups, neither in MNA-SF (0.6; 95%CI: -0.1-1.3 vs. 0.4; -0.3-1.1, p = 0.708) nor in BMI (-0.2; -0.6-0.1 vs. 0.0; -0.4-0.4 kg/m2, p = 0.290). At T12m, mean change of MNA-SF was significantly higher in IG than in CG (1.4; 0.5-2.3 vs. 0.0; -0.9-0.8; p = 0.012). BMI remained unchanged in IG, whereas it slightly declined in CG (0.0; -0.7-0.6 vs. -0.9; -1.6--0.2 kg/m2, p = 0.034). We observed rather small effects of comprehensive individualized care by pathfinders on NS in older patients 12 months after discharge. For more pronounced effects nutrition expertise might be needed.
Geriatric Assessment/methods , Nutritional Status , Patient Discharge , Transitional Care/statistics & numerical data , Aged , Aged, 80 and over , Female , Humans , Male
π-Conjugated macrocycles are molecules with unique properties that are increasingly exploited for applications and the question of whether they can sustain global aromatic or antiaromatic ring currents is particularly intriguing. However, there are only a small number of experimental studies that investigate how the properties of π-conjugated macrocycles evolve with systematic structural changes. Here, we present such a systematic experimental study of a set of [2.2.2.2]cyclophanetetraenes, all with formally Hückel antiaromatic ground states, and combine it with an in-depth computational analysis. The study reveals the central role of local and global aromaticity for rationalizing the observed optoelectronic properties, ranging from extremely large Stokes shifts of up to 1.6 eV to reversible fourfold reduction, a highly useful feature for charge storage/accumulation applications. A recently developed method for the visualization of chemical shielding tensors (VIST) is applied to provide unique insight into local and global ring currents occurring in different planes along the macrocycle. Conformational changes as a result of the structural variations can further explain some of the observations. The study contributes to the development of structure-property relationships and molecular design guidelines and will help to understand, rationalize, and predict the properties of other π-conjugated macrocycles. It will also assist in the design of macrocycle-based supramolecular elements with defined properties.
BACKGROUND: The German hospital-to-home discharge management of geriatric patients has long been criticized. The implementation of the American Transitional Care Model (TCM) could help to reduce readmissions and costs. The objective of this review was to check the scientific evidence of the cost-effectiveness of the TCM. METHODS: A systematic literature search in six databases for the time period of 26 years was conducted. The studies had to meet all pre-defined inclusion criteria. The data extraction is based on a criteria chart from literature. The methodological quality was assessed using the tools of the National Heart, Lung, and Blood Institute as well as the Consensus Health Economic Criteria list. The results transferability to German health care system was explained based on the criteria from the literature. RESULTS: Three American studies met all criteria. They showed partial cost analyses but no full economic analyses. It could be assumed that the economic effect of the TCM changes over time. The costs of a care coordinator could not be determined because few detailed information was reported. The TCM may have negative consequences for hospitals. The results are not transferable to Germany. CONCLUSION: There is no scientific evidence for the cost-effectiveness of the defined TCM. The optimal TCM duration still needs to be clarified. A detailed overview with units and prices and an additional consideration of the hospital perspective could help to make the information more transparent when deciding about the TCM implementation. A full economic analysis under German conditions or for similar European countries is necessary.
Patient Discharge , Transitional Care , Aged , Cost-Benefit Analysis , Delivery of Health Care , Hospitals , Humans , United States
INTRODUCTION: In Germany, an efficient and feasible transition from hospital to home for older patients, ensuring continuous care across healthcare settings, has not yet been applied and evaluated. Based on the transitional care model (TCM), this study aims to reduce preventable readmissions of patients ≥75 years of age with a transitional care intervention performed by geriatric-experienced care professionals. The study investigates whether the intervention ensures continuous care during transition and stabilises the care situation of patients at home. METHODS AND ANALYSES: Randomised controlled clinical trial, recruiting between 25 April 2018 and 31 December 2019 in one German hospital in the city of Regensburg. The intervention group is supported by care professionals in the transition process from hospital to home for up to 12 months. Based on TCM, the intervention includes an individual care plan according to a patient's symptoms, risks, needs and values. The plan is advanced in the domestic situation via personal visits and telephone contacts. All necessary care actions regarding, for example, mobility, residence adjustments, or nutrition, are initiated to be executed by ambulant care services, and are monitored, evaluated and adapted if necessary. In supervising the care plan, the care professionals do not administer active care services themselves but coordinate them. Patients and their caregivers are actively engaged in the care planning and execution. In contrast, the control group receives only usual discharge planning in the hospital and usual ambulatory care.The primary outcome is the all-cause readmission rate assessed using health insurance data within a follow-up of up to 12 months after hospital discharge. Secondary outcomes include care quality, mobility, nutritional and wound situation, and health-related quality of life. They are assessed at baseline, after 1 month, 3 months, 6 months, and at the end of study visit. Additionally, the economic efficiency of the intervention will be evaluated. ETHICS AND DISSEMINATION: Ethics approval for the trial was obtained from the Ethics Committee of the Friedrich-Alexander-Universität Erlangen-Nürnberg. Results will be published in peer-reviewed, open-access scientific journals and disseminated at national and international research conferences and through public presentations in the geriatric and healthcare community. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03513159.
Transitional Care , Aged , Germany , Hospitals , Humans , Patient Discharge , Quality of Life , Randomized Controlled Trials as Topic
Background: Poly( p-phenylene vinylene)s ( PPVs) and [2.2.2.2]paracyclophanetetraene ( PCT) are both composed of alternating π-conjugated para-phenylene and vinylene units. However, while the former constitute a class of π-conjugated polymers that has been used in organic electronics for decades, the latter is a macrocycle that only recently revealed its potential for applications such as organic battery electrodes. The cyclic structure endows PCT with unusual properties, and further tuning of these may be required for specific applications. Methods: In this article, we adopt an approach often used for tuning the properties of PPVs, the introduction of alkoxy (or alkylthio) substituents at the phenylene units, for tuning the optoelectronic properties of PCT. The resulting methoxy- and methylthio-substituted PCTs, obtained by Wittig cyclisation reactions, are studied by UV-vis absorption, photoluminescence, and cyclic voltammetry measurements, and investigated computationally using the visualisation of chemical shielding tensors (VIST) method. Results: The measurements show that substitution leads to slight changes in terms of absorption/emission energies and redox potentials while having a pronounced effect on the photoluminescence intensity. The computations show the effect of the substituents on the ring currents and chemical shielding and on the associated local and global (anti)aromaticity of the macrocycles, highlighting the interplay of local and global aromaticity in various electronic states. Conclusions: The study offers interesting insights into the tuneability of the properties of this versatile class of π-conjugated macrocycles.
BACKGROUND: Demographic changes are taking place in most industrialized countries. Geriatric patients are defined by the European Union of Medical Specialists as aged over 65 years and suffering from frailty and multi-morbidity, whose complexity puts a major burden on these patients, their family caregivers and the public health care system. To counteract negative outcomes and to maintain consistency in care between hospital and community dwelling, the transitional of care has emerged over the last several decades. Our objectives were to identify and summarize the components of the Transitional Care Model implemented with geriatric patients (aged over 65 years, with multi-morbidity) for the reduction of all-cause readmission. Another objective was to recognize the Transitional Care Model components' role and impact on readmission rate reduction on the transition of care from hospital to community dwelling (not nursing homes). METHODS: Randomized controlled trials (sample size ≥50 participants per group; intervention period ≥30 days), with geriatric patients were included. Electronic databases (MEDLINE, CINAHL, PsycINFO and The Cochrane Central Register of Controlled Trials) were searched from January 1994 to December 2019 published in English or German. A qualitative synthesis of the findings as well as a systematic assessment of the interventions intensities was performed. RESULTS: Three articles met the inclusion criteria. One of the included trials applied all of the nine Transitional Care Model components described by Hirschman and colleagues and obtained a high-intensity level of intervention in the intensities assessment. This and another trial reported reductions in the readmission rate (p < 0.05), but the third trial did not report significant differences between the groups in the longer follow-up period (up to 12 months). CONCLUSIONS: Our findings suggest that high intensity multicomponent and multidisciplinary interventions are likely to be effective reducing readmission rates in geriatric patients, without increasing cost. Components such as type of staffing, assessing and managing symptoms, educating and promoting self-management, maintaining relationships and fostering coordination seem to have an important role in reducing the readmission rate. Research is needed to perform further investigations addressing geriatric patients well above 65 years old, to further understand the importance of individual components of the TCM in this population.
Caregivers , Patient Care Team , Patient Readmission/statistics & numerical data , Transitional Care/standards , Aged , Aged, 80 and over , Female , Humans , Independent Living , Male , Self-Management
Reliable observation, detection and characterisation of polluted soil are of major concern in regions with military activities in order to prepare efficient decontamination. Flexible on-site analysis may be facilitated by biosensor devices. With use of fibre-optic evanescent field techniques, it has been shown that immunoaffinity reactions can be used to determine explosives sensitively. Besides antibodies as molecular recognition elements, high-affinity nucleic acids (aptamers) can be employed. Aptamers are synthetically generated and highly efficient binding molecules that can be derived for any ligand, including small organic molecules like drugs, explosives or derivatives thereof. In this paper we describe the development of specific aptamers detecting the explosives molecule TNT. The aptamers are used as a sensitive capture molecule in a fibre-optic biosensor. In addition, through the biosensor measurements the aptamers could be characterised. The advantages of the aptamer biosensor include its robustness, its ability to discriminate between different explosives molecules while being insensitive to other chemical entities in natural soil and its potential to be incorporated into a portable device. Results can be obtained within minutes. The measurement is equally useful for soil that has been contaminated for a long time and for urgent hazardous spills.
Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , Explosive Agents/analysis , Fiber Optic Technology/methods , Trinitrotoluene/analysis , Biosensing Techniques/instrumentation , Fiber Optic Technology/instrumentation , Ligands , Reproducibility of Results , Sensitivity and Specificity , Spectrometry, Fluorescence/methods , Time Factors
We describe the characterization of a DNA aptamer that displays high affinity and specificity for the anthracyclines daunomycin and doxorubicin, both of which are frequently used in chemotherapy. Aptamers were isolated from a pool of random sequences using a semiautomated procedure for magnetic beads. All selected aptamers displayed high affinity for the target molecule daunomycin. One aptamer was further characterized and exhibited a dissociation constant (KD) of 20 nM. To examine the aptamer's binding properties and clarify its applicability for diagnostic assays, its performance under various buffer conditions was evaluated. The aptamer proved to be very robust and not dependent on the presence of specific ions. It also tolerated a wide pH range and immobilization via 5'-biotinylation. Furthermore, a competition assay for sensitive daunomycin detection was established. This not only allows the determination of the aptamer's specificity but also allows the quantification of as little as 8.4 microg/L daunomycin and doxorubicin.
Anthracyclines/metabolism , Aptamers, Nucleotide/metabolism , Base Sequence , DNA Primers , Enzyme-Linked Immunosorbent Assay , Surface Plasmon Resonance
Nucleic acid aptamers, like monoclonal antibodies, bind to their target molecule with high affinity and specificity. Owing to their molecular recognition properties that are based on their three-dimensional structure, aptamers have been used as powerful tools in various fields, such as detection, separation or purification of target molecules. In addition, their intrinsic characteristics make aptamers excellent candidates for therapeutic applications. Due to their high specificity, stability, low toxicity and apparent non-immunogenicity, they provide viable alternatives to antibody- and small molecule-based therapeutics. Unlike antibodies, they can be generated against toxic, unstable or difficult to purify proteins. Furthermore, they can be chemically derivatised to extend their bioavailability and lifetimes in biological fluids, and they even offer the possibility for fast and efficient regulation. Similar to other therapeutic nucleic acids, such as antisense oligonucleotides, ribozymes or siRNA, problems with cellular uptake and susceptibility to nucleolytic attack have to be overcome for their successful application. With the first aptamer-based drug having entered the market and a few in Phase II trials, the road has been paved for more to follow. In this review, the requirements and properties of therapeutic aptamers are discussed and the recent progress in aptamer research towards drug development is highlighted.
Nucleic acid aptamers are molecules that bind to their ligands with high affinity and specificity. Unlike other functional nucleic acids such as antisense oligonucleotides, ribozymes, or siRNAs, aptamers almost never exert their effects on the genetic level. They manipulate their target molecules such as gene products or epitopes directly and site specifically, leaving nontargeted protein functions intact. In a similar way to antibodies, aptamers bind to many different kinds of target molecules with high specificity and can be made to order, but as a result of their different biochemical nature and size they can also be used complementary to antibodies. In some cases, aptamers might be more suitable or more specific than antibody approaches or small molecules, both as scientific and biotechnological tools and as therapeutic agents. Recent examples of characterization of aptamers as tools for scientific research to study regulatory circuits, as tools in diagnostic or biosensor development, and as therapeutic agents are discussed.
Drug Delivery Systems/trends , Nucleic Acids/chemistry , Nucleic Acids/therapeutic use , Oligonucleotides/chemistry , Oligonucleotides/therapeutic use , Technology, Pharmaceutical/trends , Antibodies/chemistry , Antibodies/therapeutic use , Binding Sites , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Clinical Trials as Topic , Genetic Therapy , Ligands , Models, Molecular
