Development and Validation of Nosocomial Bacterial Infection Prediction Models for Patients With Systemic Lupus Erythematosus.

BACKGROUND: Hospital-acquired bacterial infections are associated with high morbidity and mortality rates in patients with systemic lupus erythematosus (SLE). This study aimed to develop and validate predictive models for the risk of hospital-acquired bacterial infections in patients with SLE. METHODS: A historical cohort study was designed for development, and another bidirectional cohort study was used for external validation. The risk of bacterial infection was assessed upon admission and after 5 days of hospitalization. Predictor selection employed the least absolute shrinkage and selection operator (LASSO) techniques. Multiple imputations were used to handle missing data. Logistic regression models were applied, and the properties of discrimination, calibration, and decision curve analysis were evaluated. RESULTS: The development cohort comprised 1686 patients and 237 events (14.1%) from 3 tertiary hospitals. The external validation cohort included 531 patients and 84 infection outcomes (15.8%) from 10 hospital centers in Colombia (secondary and tertiary level). The models applied at admission and after 120 hours of stay exhibited good discrimination (AUC > 0.74). External validation demonstrated good performance among patients from the same tertiary institutions where the models were developed. However, geographic validation at other institutions has been suboptimal. CONCLUSIONS: Two predictive models for nosocomial bacterial infections in patients with SLE are presented. All infection prevention recommendations should be maximized in patients at moderate/high risk. Further validation studies in diverse contexts, as well as clinical impact trials, are necessary before potential applications in research and clinical care.

Enhancing rural community engagement through palliative care networks: A scoping review.

Palliative care is a crucial discipline that alleviates suffering and enhances the quality of life for patients with life-limiting illnesses and their families. However, there is gap globally between the need for and availability of these services. Integrated health service networks offer a promising solution to address this gap in rural areas, by coordinating care across different levels and sectors. This scoping review aimed at identifying the key characteristics of palliative care networks in rural communities. A broad search without time limits was conducted in four databases. Analysis and synthesis were conducted using Latent Dirichlet Allocation topic modeling. Sixteen studies were included, revealing four key themes regarding the development of palliative care networks in rural areas: community engagement is essential to secure the reach of rural networks, tailored approaches acknowledging diversity enrich these networks, team-centric efforts involving stakeholder coordination ensure successful implementation, and a multifaceted approach-empowering non-traditional stakeholders and incorporating technology resources into primary health services-dynamizes palliative care delivery in rural areas. These findings underscore the potential of collaborative and innovative approaches to enhance the accessibility and effectiveness of palliative care in underserved rural communities. Further cost-effectiveness studies are warranted to better understand the impact these strategies can have on health systems.

Time above range and no coefficient of variation is associated with diabetic retinopathy in individuals with type 1 diabetes and glycated hemoglobin within target.

AIMS: This study aimed to investigate the association between glucose metrics and diabetic retinopathy in type 1 diabetes (T1D) patients using flash continuous glucose monitoring (FGM) systems, including those maintaining glycated hemoglobin (HbA1c) within the target range. METHODS: We conducted a cross-sectional study involving 1070 T1D patients utilizing FGM systems. Data on clinical, anthropometric, and socioeconomic characteristics were collected and retinopathy was classified based on international standards. RESULTS: Patients' mean age was 47.6 ± 15.0 years, with 49.4% of them being females. Within the cohort, 24.8% of patients presented some form of retinopathy. In the analysis involving the entire sample of subjects, male gender (OR = 1.51, p = 0.027), Time Above Range (TAR) > 250 mg/dL (OR = 1.07, p = 0.025), duration of diabetes (OR = 1.09, p < 0.001), smoking (OR = 2.30, p < 0.001), and history of ischemic stroke (OR = 5.59, p = 0.025) were associated with diabetic retinopathy. No association was observed between the coefficient of variation and diabetic retinopathy (p = 0.934). In patients with HbA1c < 7%, the highest quartile of TAR > 250 was independently linked to diabetic retinopathy (OR = 8.32, p = 0.040), in addition to smoking (OR = 2.90, p = 0.031), duration of diabetes (OR = 1.09, p < 0.001), and hypertension (OR = 2.35, p = 0.040). CONCLUSION: TAR > 250 mg/dL significantly emerges as a modifiable factor associated with diabetic retinopathy, even among those patients maintaining recommended HbA1c levels. Understanding glucose metrics is crucial for tailoring treatment strategies for T1D patients.

Metadata for Data dIscoverability aNd Study rEplicability in obseRVAtional Studies (MINERVA): Development and Pilot of a Metadata List and Catalogue in Europe.

PURPOSE: Metadata for data dIscoverability aNd study rEplicability in obseRVAtional studies (MINERVA), a European Medicines Agency-funded project (EUPAS39322), defined a set of metadata to describe real-world data sources (RWDSs) and piloted metadata collection in a prototype catalogue to assist investigators from data source discoverability through study conduct. METHODS: A list of metadata was created from a review of existing metadata catalogues and recommendations, structured interviews, a stakeholder survey, and a technical workshop. The prototype was designed to comply with the FAIR principles (findable, accessible, interoperable, reusable), using MOLGENIS software. Metadata collection was piloted by 15 data access partners (DAPs) from across Europe. RESULTS: A total of 442 metadata variables were defined in six domains: institutions (organizations connected to a data source); data banks (data collections sustained by an organization); data sources (collections of linkable data banks covering a common underlying population); studies; networks (of institutions); and common data models (CDMs). A total of 26 institutions were recorded in the prototype. Each DAP populated the metadata of one data source and its selected data banks. The number of data banks varied by data source; the most common data banks were hospital administrative records and pharmacy dispensation records (10 data sources each). Quantitative metadata were successfully extracted from three data sources conforming to different CDMs and entered into the prototype. CONCLUSIONS: A metadata list was finalized, a prototype was successfully populated, and a good practice guide was developed. Setting up and maintaining a metadata catalogue on RWDSs will require substantial effort to support discoverability of data sources and reproducibility of studies in Europe.

Experimental Analysis of Stress Shielding Effects in Screw Spacers Placed in Porcine Spinal Tissue.

Bone cortical tissues reorganize and remodel in response to tensile forces acting on them, while compressive forces cause atrophy. However, implants support most of the payload. Bones do not regenerate, and stress shielding occurs. The aim is to analyze the biomechanical behavior of a lumbar cage to study the implant's stress shielding. The ASTM E-9 standard was used with the necessary adjustments to perform compression tests on lumbar and thoracic porcine spinal vertebrae. Twelve cases were analyzed: six with the metal prosthesis and six with the PEEK implant. A mathematical model based on the Hertz contact theory is proposed to assess the stress shielding for endoprosthesis used in spine pathologies. The lumbar spacer (screw) helps to reduce the stress shielding effect due to the ACME thread. The best interspinous spacer is the PEEK screw. It does not embed in bone. The deformation capability increases by 11.5% and supports 78.6 kg more than a system without any interspinous spacer.

Association between precipitation and mortality due to diarrheal diseases by climate zone: A multi-country modeling study.

Background: Precipitation could affect the transmission of diarrheal diseases. The diverse precipitation patterns across different climates might influence the degree of diarrheal risk from precipitation. This study determined the associations between precipitation and diarrheal mortality in tropical, temperate, and arid climate regions. Methods: Daily counts of diarrheal mortality and 28-day cumulative precipitation from 1997 to 2019 were analyzed across 29 locations in eight middle-income countries (Argentina, Brazil, Costa Rica, India, Peru, the Philippines, South Africa, and Thailand). A two-stage approach was employed: the first stage is conditional Poisson regression models for each location, and the second stage is meta-analysis for pooling location-specific coefficients by climate zone. Results: In tropical climates, higher precipitation increases the risk of diarrheal mortality. Under extremely wet conditions (95th percentile of 28-day cumulative precipitation), diarrheal mortality increased by 17.8% (95% confidence interval [CI] = 10.4%, 25.7%) compared with minimum-risk precipitation. For temperate and arid climates, diarrheal mortality increases in both dry and wet conditions. In extremely dry conditions (fifth percentile of 28-day cumulative precipitation), diarrheal mortality risk increases by 3.8% (95% CI = 1.2%, 6.5%) for temperate and 5.5% (95% CI = 1.0%, 10.2%) for arid climates. Similarly, under extremely wet conditions, diarrheal mortality risk increases by 2.5% (95% CI = -0.1%, 5.1%) for temperate and 4.1% (95% CI = 1.1%, 7.3%) for arid climates. Conclusions: Associations between precipitation and diarrheal mortality exhibit variations across different climate zones. It is crucial to consider climate-specific variations when generating global projections of future precipitation-related diarrheal mortality.

Multimorbidity in Incident Heart Failure: Characterisation and Impact on 1-Year Outcomes.

Background/Objectives: Heart failure (HF) is usually accompanied by other comorbidities, which, altogether, have a major impact on patients and healthcare systems. Our aim was to analyse the demographic and clinical characteristics of incident HF patients and the effect of comorbidities on one-year health outcomes. Methods: This was an observational, retrospective, population-based study of incident HF patients between 2014 and 2018 in the EpiChron Cohort, Spain. The included population contained all primary and hospital care patients with a diagnosis of HF. All chronic diseases in their electronic health records were pooled into three comorbidity clusters (cardiovascular, mental, other physical). These comorbidity groups and the health outcomes were analysed until 31 December 2018. A descriptive analysis was performed. Cox regression models and survival curves were calculated to determine the hazard risk (HR) of all-cause mortality, all-cause and HF-related hospital admissions, hospital readmissions, and emergency room visits for each comorbidity group. Results: In total, 13,062 incident HF patients were identified (mean age = 82.0 years; 54.8% women; 93.7% multimorbid; mean of 4.52 ± 2.06 chronic diseases). After one-year follow-up, there were 3316 deaths (25.3%) and 4630 all-cause hospitalisations (35.4%). After adjusting by gender, age, and inpatient/outpatient status, the mental cluster was associated (HR; 95% confidence interval) with a higher HR of death (1.08; 1.01-1.16) and all-cause hospitalisation (1.09; 1.02-1.16). Conclusions: Cardiovascular comorbidities are the most common and studied ones in HF patients; however, they are not the most strongly associated with negative impacts on health outcomes in these patients. Our findings suggest the importance of a holistic and integral approach in the care of HF patients and the need to take into account the entire spectrum of comorbidities for improving HF management in clinical practice.

Hybrid deep learning models for the screening of Diabetic Macular Edema in optical coherence tomography volumes.

Several studies published so far used highly selective image datasets from unclear sources to train computer vision models and that may lead to overestimated results, while those studies conducted in real-life remain scarce. To avoid image selection bias, we stacked convolutional and recurrent neural networks (CNN-RNN) to analyze complete optical coherence tomography (OCT) cubes in a row and predict diabetic macular edema (DME), in a real-world diabetic retinopathy screening program. A retrospective cohort study was carried out. Throughout 4-years, 5314 OCT cubes from 4408 subjects who attended to the diabetic retinopathy (DR) screening program were included. We arranged twenty-two (22) pre-trained CNNs in parallel with a bidirectional RNN layer stacked at the bottom, allowing the model to make a prediction for the whole OCT cube. The staff of retina experts built a ground truth of DME later used to train a set of these CNN-RNN models with different configurations. For each trained CNN-RNN model, we performed threshold tuning to find the optimal cut-off point for binary classification of DME. Finally, the best models were selected according to sensitivity, specificity, and area under the receiver operating characteristics curve (AUROC) with their 95% confidence intervals (95%CI). An ensemble of the best models was also explored. 5188 cubes were non-DME and 126 were DME. Three models achieved an AUROC of 0.94. Among these, sensitivity, and specificity (95%CI) ranged from 84.1-90.5 and 89.7-93.3, respectively, at threshold 1, from 89.7-92.1 and 80-83.1 at threshold 2, and from 80.2-81 and 93.8-97, at threshold 3. The ensemble model improved these results, and lower specificity was observed among subjects with sight-threatening DR. Analysis by age, gender, or grade of DME did not vary the performance of the models. CNN-RNN models showed high diagnostic accuracy for detecting DME in a real-world setting. This engine allowed us to detect extra-foveal DMEs commonly overlooked in other studies, and showed potential for application as the first filter of non-referable patients in an outpatient center within a population-based DR screening program, otherwise ended up in specialized care.

Comparing the Need and Development of Pediatric Palliative Care in Mexico: A Geographical Analysis.

CONTEXT: The Global Atlas of Palliative Care (GAPC) ranked Mexico's palliative care services at a preliminary integration stage into mainstream healthcare services. However, this data does not reflect pediatric palliative care (PPC) development. OBJECTIVES: To analyze the current need and level of development of PPC within Mexico. METHODS: PPC need was estimated using causes of death associated with serious health-related suffering from national mortality data from the General Directorate of Health Information. The level of development was measured through six indicators involving access to PPC services and opioids, then classified using the GAPC development categories adapted to regional territories based on available data. RESULTS: In 2021, 37,444 children died in Mexico. Of those, 10,677 (28.29%) died from conditions with serious health-related suffering, averaging a need for PPC of 25/100,000 children. Out of Mexico's 32 states, two (6.2%) had no PPC activity (category 1), twenty (62.6%) were in a capacity-building phase (category 2), eight (25%) had isolated PPC provision (category 3a), while two (6.2%) had generalized PPC provision (category 3b). No state had early (category 4a) or advanced PPC integration (category 4b). Overall, Mexico was classified as category 2. CONCLUSIONS: PPC services are distributed unevenly across the country, leading to inequitable access to care and an inability to meet the needs of patients and families. There is a disparity between the level of development of adult palliative care services and the underdevelopment of PPC in Mexico. This information can help stakeholders guide the development of PPC where it is needed most.

Temporal Trends in Transcatheter Aortic Valve Implantation: 10-Year Analysis of the TAVIDOR Registry. / Tendência Temporal no Implante Percutâneo de Bioprótese Aórtica: Análise de 10 Anos do Registro TAVIDOR.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has established itself as the preferential strategy to approach severe aortic stenosis. Information on procedural improvements and nationwide results obtained with the technique throughout the past decade are unknown. OBJECTIVES: To assess the temporal variation of the demographic profile, procedural characteristics, and in-hospital outcomes of patients undergoing TAVI procedures at the Rede D'Or São Luiz. METHODS: Observational registry comprising 29 national institutions, comparing the characteristics of the TAVI procedures performed from 2012 to 2017 (Group 1) to those performed from 2018 to 2023 (Group 2). The statistical significance level adopted was p < 0.05. RESULTS: This study assessed 661 patients, 95 in Group 1 and 566 in Group 2, with a mean age of 81.1 years. Group 1 patients had a higher prevalence of New York Heart Association functional class III or IV and STS risk score > 8%. In addition, they more often underwent general anesthesia, transesophageal echocardiographic monitoring, and access through femoral dissection. Group 2 patients had a higher success rate of the TAVI procedure (95.4% versus 89.5%; p = 0.018), lower mortality (3.9% versus 11.6%; p = 0.004), and less often needed permanent pacemaker implantation (8.5% versus 17.9%; p = 0.008). CONCLUSIONS: The 10-year temporal trends analysis of the TAVIDOR Registry shows a reduction in patients' clinical complexity over time. Furthermore, the advance to minimalistic implantation techniques, added to the technological evolution of the devices, may have contributed to the favorable outcomes observed among those whose implantation occurred in the last 5 years studied.

FUNDAMENTO: O implante percutâneo de bioprótese valvar aórtica (TAVI) consolidou-se como opção terapêutica da estenose aórtica de grau importante. Dados sobre as características evolutivas dos procedimentos e dos resultados obtidos com a técnica ao longo da última década, em escala nacional, são desconhecidos. OBJETIVOS: Analisar a tendência temporal referente ao perfil demográfico, características dos procedimentos e desfechos hospitalares de pacientes submetidos a TAVI na Rede D'Or São Luiz. MÉTODOS: Registro observacional envolvendo 29 instituições nacionais. Comparou-se características dos procedimentos realizados de 2012 a 2017 (Grupo 1) e de 2018 a 2023 (Grupo 2). Foram considerados significantes os resultados com valor de p < 0,05. RESULTADOS: Foram analisados 661 casos, 95 pertencentes ao Grupo 1 e 566 ao Grupo 2. A média de idade foi 81,1 anos. Observou-se no Grupo 1 maior prevalência de pacientes em classe funcional III ou IV e escore de risco > 8%. Foi mais frequente o emprego de anestesia geral, monitorização ecocardiográfica transesofágica e via de acesso por dissecção. Maior taxa de sucesso do procedimento (95,4% versus 89,5%; p = 0,018) foi aferida em implantes efetivados a partir de 2018, assim como menor mortalidade (3,9% versus 11,6%; p = 0,004) e necessidade de marcapasso definitivo (8,5% versus 17,9%; p = 0,008). CONCLUSÕES: A análise temporal de 10 anos do Registro TAVIDOR demonstra uma queda na complexidade clínica dos pacientes. Além disso, o avanço para técnicas de implante minimalistas, somadas à evolução tecnológica dos dispositivos, podem ter contribuído para desfechos favoráveis dentre aqueles cujo implante ocorreu no último quinquênio.

Underdiagnosis of umbilical hernias in CT scans in a multicenter study - the radiologically neglected pathology and its surgical implications.

PURPOSE: Umbilical hernias (UH) have a higher prevalence than previously considered. With the high workload radiologists must endure, UH can be missed when interpreting a computed tomography scan (CT). The clinical implications of its misdiagnosis are yet to be determined. Unreporting could lead to content lesions in surgical approaches and other potential complications. The aim was to determine the prevalence of UH using CT scans, and the incidence of radiological reporting. METHODS: A multicenter, cross-sectional study was performed in four tertiary-level hospitals. CT scans were reviewed for abdominal wall defects at the umbilicus, and radiological reports were examined to compare findings. In the case of UH, transversal, anteroposterior, and craniocaudal lengths were obtained. RESULTS: A total of 1557 CTs were included, from which 971 (62.4%, 95% CI 0.59-0.64) had UH. Out of those, 629 (64.8%, 95% CI 0.61-0.67) of the defects were not included in the radiological report. Smaller UH (x̄: 7.7 × 6.0 mm) were more frequently missed. Of the reported UH, 187 (54.7%) included at least one axis measurement, 289 (84.5%) content description, and 146 (42.7%) whether or not there were complication signs. CONCLUSION: There is a high prevalence of UH, and a high incidence of under-reporting. This raises the question of whether this is a population-based finding or the norm worldwide. The reason of under-reporting and the clinical implications of these must be addressed in further studies.

Accessibility to palliative care services in Colombia: an analysis of geographic disparities.

OBJECTIVES: Due to the increase in the prevalence of non-communicable diseases and the Colombian demographic transition, the necessity of palliative care has arisen. This study used accessibility and coverage indicators to measure the geographic barriers to palliative care. METHODS: Population-based observational study focused on urban areas and adult population from Colombia, which uses three measurements of geographic accessibility to services: a) density of palliative care services per 100,000 inhabitants, b) analysis of geographic distribution by territorial nodes of the country, and c) spatial analysis of palliative care services using Voronoi diagrams. ArcGIS Pro software was used to map services' locations and identify geographic disparities. RESULTS: A total of 504 palliative care services were identified, of which 77% were primary health care services. The density of palliative care services in Colombia is 1.8 primary care services per 100,000 inhabitants and 0.4 specialized services per 100,000 inhabitants. The average palliative care coverage is 41%, two regions of the country have a coverage below 30%. Twenty-eight percent of the services provide care for a population greater than 50,000 inhabitants within their coverage area, exceeding the acceptable limit by international standards. CONCLUSIONS: Palliative care services are concentrated in three main regions (Bogotá D.C., the Center, and the Caribbean) and are limited in the Orinoquia and Amazonia nodes. Density of specialized palliative care services is extremely low and there are regions without palliative services for adults with palliative needs.

Palliative care education in undergraduate medical and nursing programs in Colombia: a cross-sectional analysis.

BACKGROUND: The number of people suffering from chronic diseases requiring palliative care (PC) is increasing rapidly. Therefore, PC teaching in undergraduate health science programs is necessary to improve primary PC based on international recommendations and available scientific evidence. METHODS: A descriptive cross-sectional study was conducted. Active undergraduate medical and nursing programs that were approved by the Colombian Ministry of Education and integrated PC teaching into their curricula were included in the study. The total sample consisted of 48 programs: 31 nursing and 17 medical programs. RESULTS: PC competencies are distributed throughout the curriculum in 41.67% of programs, in elective courses in 31.25%, and in mandatory courses in 27.08% of the programs. The average PC teaching hours is 81 for nursing and 57.6 for medicine. PC clinical rotations are not offered in 75% of the programs. For undergraduate nursing programs, the most frequent competencies taught are the definition and history of PC and identifying common symptoms associated with advanced disease. In undergraduate medicine, the most common competencies are pharmacological and non-pharmacological pain management and identification of PC needs. CONCLUSIONS: PC teaching in undergraduate health science programs mainly addresses the conceptual and theoretical aspects of PC, which are part of the competencies present throughout the programs' curricula. Low availability of PC clinical rotations was identified. Future studies should assess whether the low availability of clinical rotations in PC limits the ability of students to develop the practical competencies necessary to provide quality PC. TRIAL REGISTRATION: Not applicable.

Multimorbidity patterns and trajectories in young and middle-aged adults: a large-scale population-based cohort study.

Introduction: The presence of multiple chronic conditions, also referred to as multimorbidity, is a common finding in adults. Epidemiologic research can help identify groups of individuals with similar clinical profiles who could benefit from similar interventions. Many cross-sectional studies have revealed the existence of different multimorbidity patterns. Most of these studies were focused on the older population. However, multimorbidity patterns begin to form at a young age and can evolve over time following distinct multimorbidity trajectories with different impact on health. In this study, we aimed to identify multimorbidity patterns and trajectories in adults 18-65 years old. Methods: We conducted a retrospective longitudinal epidemiologic study in the EpiChron Cohort, which includes all inhabitants of Aragón (Spain) registered as users of the Spanish National Health System, linking, at the patient level, information from electronic health records from both primary and specialised care. We included all 293,923 patients 18-65 years old with multimorbidity in 2011. We used cluster analysis at baseline (2011) and in 2015 and 2019 to identify multimorbidity patterns at four and eight years of follow-up, and we then created alluvial plots to visualise multimorbidity trajectories. We performed age- and sex-adjusted logistic regression analysis to study the association of each pattern with four- and eight-year mortality. Results: We identified three multimorbidity patterns at baseline, named dyslipidaemia & endocrine-metabolic, hypertension & obesity, and unspecific. The hypertension & obesity pattern, found in one out of every four patients was associated with a higher likelihood of four- and eight-year mortality (age- and sex-adjusted odds ratio 1.11 and 1.16, respectively) compared to the unspecific pattern. Baseline patterns evolved into different patterns during the follow-up. Discussion: Well-known preventable cardiovascular risk factors were key elements in most patterns, highlighting the role of hypertension and obesity as risk factors for higher mortality. Two out of every three patients had a cardiovascular profile with chronic conditions like diabetes and obesity that are linked to low-grade systemic chronic inflammation. More studies are encouraged to better characterise the relatively large portion of the population with an unspecific disease pattern and to help design and implement effective and comprehensive strategies towards healthier ageing.

Impact of CFTR modulator therapy on body composition as assessed by thoracic computed tomography: A follow-up study.

OBJECTIVE: Treatment with cystic fibrosis transmembrane conductance regulator (CFTR) modulators in individuals with cystic fibrosis (CF) has brought a significant change in forced expiratory volume in 1 second (FEV1) and clinical parameters. However, it also results in weight gain. The aim of our study is to evaluate the effect of CFTR modulator treatment on body composition, measured by computed tomography (CT). METHODS: Adult subjects with CF under follow-up at La Princesa University Hospital were recruited. All of them were on elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA) treatment. Body composition analysis was conducted using CT scans and an open-source software. The results were then compared with bioimpedance estimations, as well as other clinical and spirometry data. RESULTS: Our sample consisted of 26 adult subjects. The fat mass compartments on CT scans correlated with similar compartments on bioimpedance, and normal-density muscle mass exhibited a strong correlation with phase angle. Higher levels of very low-density muscle prior to treatment were associated with lower final FEV1 and less improvement in FEV1 after therapy. We observed an increase in total body area (P < 0.001), driven by increases in total fat mass (P < 0.001), subcutaneous fat (P < 0.001), visceral fat (P = 0.002), and intermuscular fat (P = 0.022). The only muscle compartment that showed an increase after treatment was very low-density muscle (P = 0.032). CONCLUSIONS: CT scans represent an opportunity to assess body composition on CF. Combination treatment with CFTR modulators, leads to an improvement in FEV1 and to an increase in body mass in all compartments primarily at the expense of fat mass.

AptaShield: A Universal Signal-Transduction System for Fast and High-Throughput Optical Molecular Biosensing.

Biosensing technologies are often described to provide facile, sensitive, and minimally to noninvasive detection of molecular analytes across diverse scientific, environmental, and clinical diagnostic disciplines. However, commercialization has been very limited mostly due to the difficulty of biosensor reconfiguration for different analyte(s) and limited high-throughput capabilities. The immobilization of different biomolecular probes (e.g., antibodies, peptides, and aptamers) requires the sensor surface chemistry to be tailored to provide optimal probe coupling, orientation, and passivation and prevent nonspecific interactions. To overcome these challenges, here we report the development of a solution-phase biosensor consisting of an engineered aptamer, the AptaShield, capable of universally binding to any antigen recognition site (Fab') of fluorescently labeled immunoglobulins (IgG) produced in rabbits. The resulting AptaShield biosensor relies on a low affinity dynamic equilibrium between the fluorescently tagged aptamer and IgG to generate a specific Förster resonance energy transfer (FRET) signal. As the analyte binds to the IgG, the AptaShield DNA aptamer-IgG complex dissociates, leading to an analyte concentration-dependent decrease of the FRET signal. The biosensor demonstrates high selectivity, specificity, and reproducibility for analyte quantification in different biological fluids (e.g., urine and blood serum) in a one-step and low sample volume (0.5-6.25 µL) format. The AptaShield provides a universal signal transduction mechanism as it can be coupled to different rabbit antibodies without the need for aptamer modification, therefore representing a robust high-throughput solution-phase technology suitable for point-of-care applications, overcoming the current limitations of gold standard enzyme-linked immunosorbent assays (ELISA) for molecular profiling.