Passive and reversible area regulation of supported lipid bilayers in response to fluid flow.

Biological and model membranes are frequently subjected to fluid shear stress. However, membrane mechanical responses to flow remain incompletely described. This is particularly true of membranes supported on a solid substrate, and the influences of membrane composition and substrate roughness on membrane flow responses remain poorly understood. Here, we combine microfluidics, fluorescence microscopy, and neutron reflectivity to explore how supported lipid bilayer patches respond to controlled shear stress. We demonstrate that lipid membranes undergo a significant, passive, and partially reversible increase in membrane area due to flow. We show that these fluctuations in membrane area can be constrained, but not prevented, by increasing substrate roughness. Similar flow-induced changes to membrane structure may contribute to the ability of living cells to sense and respond to flow.

Measuring flow-mediated protein drift across stationary supported lipid bilayers.

Fluid flow near biological membranes influences cell functions such as development, motility, and environmental sensing. Flow can laterally transport extracellular membrane proteins located at the cell-fluid interface. To determine whether this transport contributes to flow signaling in cells, quantitative knowledge of the forces acting on membrane proteins is required. Here, we demonstrate a method for measuring flow-mediated lateral transport of lipid-anchored proteins. We rupture giant unilamellar vesicles to form discrete patches of supported membrane inside rectangular microchannels and then allow proteins to bind to the upper surface of the membrane. While applying flow, we observe the formation of protein concentration gradients that span the membrane patch. By observing how these gradients dynamically respond to changes in applied shear stress, we determine the flow mobility of the lipid-anchored protein. We use simplified model membranes and proteins to demonstrate our method's sensitivity and reproducibility. Our intention was to design a quantitative, reliable method and analysis for protein mobility that we will use to compare flow transport for a variety of proteins, lipid anchors, and membranes in model systems and on living cells.

Safety and Efficacy of Immune Checkpoint Inhibitors in Patients with Cancer and Viral Hepatitis: The MD Anderson Cancer Center Experience.

BACKGROUND: Despite the clinical benefit of immune checkpoint inhibitors (ICIs), patients with a viral hepatitis have been excluded from clinical trials because of safety concerns. The purpose of this study was to determine the incidence rate of adverse events (AEs) in patients with viral hepatitis who received ICIs for cancer treatment. MATERIALS AND METHODS: We conducted a retrospective study in patients with cancer and concurrent hepatitis B or C, who had undergone treatment with ICI at MD Anderson Cancer Center from January 1, 2010 to December 31, 2019. RESULTS: Of the 1076 patients screened, we identified 33 with concurrent hepatitis. All 10 patients with HBV underwent concomitant antiviral therapy during ICI treatment. Sixteen of the 23 patients with HCV received it before the initiation of ICI. The median follow-up time was 33 months (95% CI, 23-45) and the median duration of ICI therapy was 3 months (IQR, 1.9-6.6). Of the 33 patients, 12 (39%) experienced irAEs (immune-related adverse events) of any grade, with 2 (6%) having grade 3 or higher. None of the patients developed hepatitis toxicities. CONCLUSION: ICIs may be a therapeutic option with an acceptable safety profile in patients with cancer and advanced liver disease.

Immune Checkpoint Inhibitors Suppress Hepatitis C Virus Replication in Infected Patients With Solid Tumors.

INTRODUCTION: Data are scarce regarding the virologic impact and safety of immune checkpoint inhibitors (ICI) in patients with chronic hepatitis C virus (HCV) infection. We examined the virologic impact of ICI in HCV-infected patients with solid tumors and their safety. METHODS: HCV-infected patients with solid tumor treated with ICI at our institution between April 26, 2016, and January 5, 2022, were enrolled in a prospective observational study. The primary outcomes were ICI-induced changes in HCV viremia (HCV inhibition and HCV reactivation) and safety of ICI. RESULTS: We enrolled 52 consecutive patients with solid tumors treated with ICI. Most were men (41; 79%), White (31; 59%), without cirrhosis (34; 65%), and with HCV genotype 1 (40; 77%). Four patients (7.7%) experienced HCV inhibition while receiving ICI including 1 patient who developed undetectable viremia for 6 months in the absence of direct-acting antivirals (DAA). Two patients (4%) developed HCV reactivation, both while receiving immunosuppressive therapy for ICI-related toxic effects. Adverse events occurred in 36 patients (69%), and 39 of the 47 adverse events (83%) were grade 1-2. Grade 3-4 adverse events occurred in 8 patients (15%), and in all cases, they were related to ICI, not to HCV. No HCV-associated liver failure or death occurred. DISCUSSION: Inhibition of HCV replication with virologic cure can develop in patients receiving ICI without DAA. HCV reactivation occurs primarily in patients receiving immunosuppressants for ICI-related toxic effects. ICI are safe in HCV-infected patients with solid tumors. Chronic HCV infection should not be considered a contraindication for ICI therapy.

Preparation of a Rigid and Nearly Coplanar Bis-tetracene Dimer through an Application of the CANAL Reaction.

A rigid tetracene dimer with a substantial interchromophore distance has been prepared through an application of the recently developed catalytic arene-norbornene annulation (CANAL) reaction. An iterative cycloaddition route was found to be unsuccessful, so a shorter route was adopted whereby fragments were coupled in the penultimate step to form a 13:1 mixture of two diastereomers, the major of which was isolated and crystallized. Constituent tetracene moieties are linked with a rigid, well-defined bridge and feature a near-co-planar mutual orientation of the acenes.

Strategies to identify hepatitis C virus infection in patients receiving anticancer therapy: a cross-sectional study.

BACKGROUND: Optimal hepatitis C virus (HCV) screening strategies for cancer patients have not been established. We compared the performance of selective HCV screening strategies. METHODS: We surveyed patients presenting for first systemic anticancer therapy during 2013-2014 for HCV risk factors. We estimated the prevalence of positivity for HCV antibody (anti-HCV) and examined factors associated with anti-HCV status using Fisher's exact test or Student's t test. Sensitivity was calculated for screening patients born during 1945-1965, patients with ≥ 1 other risk factor, or both cohorts ("combined screening"). RESULTS: We enrolled 2122 participants. Median age was 59 years (range, 18-91); 1138 participants were women. Race/ethnicity distribution was white non-Hispanic, 76% (n = 1616); Hispanic, 11% (n = 233); black non-Hispanic, 8% (n = 160); Asian, 4% (n = 78); and other, 2% (n = 35). Primary cancer distribution was non-liver solid tumor, 78% (n = 1664); hematologic cancer, 20% (n = 422); and liver cancer, 1% (n = 28). Prevalence of anti-HCV was 1.93% (95% CI, 1.39%-2.61%). Over 28% of patients with detectable HCV RNA were unaware of infection. Factors significantly associated with anti-HCV positivity included less than a bachelor's degree, birth in 1945-1965, chronic liver disease, injection drug use, and blood transfusion or organ transplant before 1992. A total of 1315 participants (62%), including 39 of 41 with anti-HCV, reported ≥ 1 risk factor. Sensitivity was 80% (95% CI, 65-91%) for birth-cohort-based, 68% (95% CI, 52-82%) for other-risk-factor-based, and 95% (95% 83-99%) for combined screening. CONCLUSION: Combined screening still missed 5% of patients with anti-HCV. These findings favor universal HCV screening to identify all HCV-infected cancer patients.

Hepatobiliary and Pancreatic Adverse Events.

The expanded approval of immune checkpoint inhibitors (ICIs) for the treatment of multiple cancer types has offered patients more opportunities in treatment selection and survival.Hepatotoxicity is a well-recognized immune-related adverse event (irAE) associated with treatment with ICI. It is considered a type of drug-induced liver injury (DILI). Depending on the specific ICI and whether the patient receives single- or dual-drug therapy, the incidence of hepatotoxicity in general could be as high as 30%. As more patients receive treatment with ICI, more cases of hepatotoxicity are expected to occur. Clinicians must exercise close pharmacovigilance to recognize liver-related irAEs early.ICI-mediated hepatobiliary toxicity (or "IMH") generally presents as asymptomatic elevations of alanine transaminase and aspartate transaminase, with or without alkaline phosphatase elevation. Some patients may present with jaundice, fever, or malaise. Rarely, it may cause liver failure and death. The diagnosis of IMH is made after careful exclusion of other causes of acute hepatitis based on medical history, laboratory evaluation, imaging, and liver histological findings. In clinically significant cases of IMH, the management involves discontinuation of ICI followed by close monitoring and the initiation of immunosuppression. Current society guidelines, which are not based on robust evidence, specify treatment recommendations depending on the grade of liver injury, according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. However, our clinical experience suggests possible alternatives, including lower corticosteroid dosing with adjunct therapies. Whereas current guidelines endorse permanent cessation of future ICI treatment in patients diagnosed with grades 3-4 IMH, published clinical experience suggests potential for flexibility when assessing for candidacy of resuming ICI.Because histologic bile duct injury has been observed in cases ascribed to IMH, ICI-mediated cholangiopathic disease probably exists on a spectrum within IMH. Even extrahepatic bile duct involvement has been observed. This phenotype warrants special considerations in treatment and surveillance.ICI-related cholecystitis has been rarely reported in the literature. Management follows current standards of care for typical cases of cholecystitis. No relationship with ICI-mediated cholangiopathic disease has been observed.Assessing for and managing ICI-associated pancreatic injury remain challenging to the clinician. Many cases of asymptomatic serum lipase elevation are detected on routine labs without clinical signs or symptoms of typical acute pancreatitis. However, symptomatic patients should be initially managed like traditional cases of acute pancreatitis requiring hospitalization for evaluation and inpatient management.

Clinical Characteristics and Adverse Impact of Hepatotoxicity due to Immune Checkpoint Inhibitors.

INTRODUCTION: We conducted this study to characterize the incidence, clinical features, treatment, and outcomes of immune checkpoint inhibitor (ICI) hepatotoxicity. METHODS: Patients who received ICIs (with either single-agent or combination regimens) from January 1, 2010, to March 31, 2018, were identified. Hepatotoxicity was defined as alanine aminotransferase (ALT) >5 times the upper limit of normal (ULN), in the absence of an alternate cause, and categorized as grade 3 (ALT 5-20× ULN) or grade 4 (ALT >20× ULN), according to Common Terminology Criteria for Adverse Events 4.03. RESULTS: Among 5,762 patients, 100 (2%) developed hepatotoxicity, occurring in a higher proportion of recipients of combination therapy (9.2%) compared with monotherapy (up to 1.7%, P < 0.001). ICIs were discontinued permanently in 69 and temporarily in 31 patients. Sixty-seven patients received steroids, 10 of whom (14%) had recurrent hepatotoxicity after the steroid taper. Thirty-one patients resumed ICIs after ALT improvement, 8 of whom (26%) developed recurrent hepatotoxicity. Characteristics of liver injury, response to steroids, and outcomes were similar between 38 individuals with and 62 without possible pre-existing liver disease. The severity and outcome of hepatotoxicity due to combination therapy were not significantly different from monotherapy. There were 36 deaths. Two had liver failure at the time of death, both with progression of liver metastases and grade 3 hepatotoxicity. DISCUSSION: Clinically significant ICI-related hepatotoxicity was uncommon but led to permanent ICI discontinuation in the majority. ICIs were restarted in a sizable proportion of patients, most of whom did not experience recurrent hepatotoxicity.

Gender Matters: Characteristics of Hepatocellular Carcinoma in Women From a Large, Multicenter Study in the United States.

INTRODUCTION: Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide, affecting men to women at a ratio of about 4:1. Risk factors, characteristics, and outcomes for HCC in women in the United States remain poorly understood; therefore, we aim to explore gender differences further. METHODS: Patients diagnosed with HCC between January 2000 and June 2014 at 5 large centers were identified. Clinical information, tumor characteristics, and survival data were extracted manually. The presence of underlying cirrhosis was assessed based on published criteria. RESULTS: Of 5,327 patients with HCC in our cohort, 1,203 (22.6%) were women. There were important differences in the underlying etiology of liver disease between the 2 genders (P < 0.0001): women had a significantly higher frequency of nonalcoholic fatty liver disease (23% vs 12%) and lower frequency of alcoholic liver disease (5% vs 15%). The proportion of noncirrhotic HCC was significantly higher among women (17% vs 10%, P < 0.0001). Women had less-advanced HCC at presentation by tumor, node, metastasis staging (P < 0.0001) and a higher proportion within Milan criteria (39% vs 35%, P = 0.002). Women had a greater overall survival (2.5 ± 2.9 years vs 2.2 ± 2.7 years, P = 0.0031). DISCUSSION: The frequency of underlying nonalcoholic fatty liver disease and noncirrhotic HCC were significantly higher in women than men in this large cohort. Women presented with less-advanced HCC and had a greater overall survival. Further investigation is warranted to explore potential mechanisms and implications for these gender differences, especially with noncirrhotic HCC (see Visual Abstract, Supplementary Digital Content 1, http://links.lww.com/AJG/B535).

Best practices for detection, assessment and management of suspected immune-mediated liver injury caused by immune checkpoint inhibitors during drug development.

Immune checkpoint inhibitors (ICIs) have shown significant efficacy in patients with various malignancies, however, they are associated with a wide range of immune-related toxicities affecting many organs, including the liver. Immune-mediated liver injury caused by checkpoint inhibitors (ILICI) is a distinctive form of drug induced liver injury (DILI), that differs from most DILI types in presumed underlying mechanism, incidence, and response to therapeutic interventions. Despite increased awareness of ILICI and other immune-related adverse effects of ICIs reflected by recent guidelines for their management in post marketing clinical practice, there is lack of uniform best practices to address ILICI risk during drug development. As efforts to develop safer and more effective ICIs for additional indications grow, and as combination therapies including ICIs are increasingly investigated, there is a growing need for consistent practices for ILICI in drug development. This publication summarizes current best practices to optimize the monitoring, diagnosis, assessment, and management of suspected ILICI in clinical trials using ICI as a single agent and in combination with other ICIs or other oncological agents. It is one of several publications developed by the IQ DILI Initiative in collaboration with DILI experts from academia and regulatory agencies. Recommended best practices are outlined pertaining to hepatic inclusion and exclusion criteria, monitoring of liver tests, ILICI detection, approach to a suspected ILICI signal, causality assessment, hepatic discontinuation rules and additional medical treatment.

Exploring Generational Differences in Physicians' Perspectives on the Proliferation of Technology within the Medical Field: A Narrative Study.

BACKGROUND: The development and advancement of information and communication technologies (ICTs), such as electronic libraries, electronic medical records and computerized physician order entry systems, have made learning and acquiring vast medical knowledge feasible. However, there are limited data pertaining to the navigation of such technologies among physicians of varying generational cohorts. OBJECTIVE: The aim of this study was to explore physician experiences and perspectives influencing the adoption of ICTs, with an emphasis on generational differences. METHODS: Semi-structured interviews with focus groups or individual physicians were conducted, recorded and transcribed to elicit key themes. RESULTS: Across the generations, participants expressed several benefits to ICTs, such as accessibility, efficiency and use of current, evidence-based practice medicine. Common problems encountered included usability issues, downtimes, alarm fatigue, and administrative tasks. There were differences between generations regarding adaptability, perceived benefits and drawbacks and perceptions of other generations' ability to adapt. CONCLUSION: Physicians from various generations recognized the overall benefits of implementing ICTs. Although some drawbacks were reported, all participants understood the necessity of ICTs. Furthermore, implementation should be tailored to physician working style and learning needs.

Leveraging Digital Infrastructure for Data Analysis: An Example in Bariatric Surgery.

BACKGROUND: The digitalization of healthcare information provides hospitals with the ability to gain insight into patterns and associations pertaining to disease and management. Using bariatric patient data as an example provided an opportunity to explore the potential of electronic medical record (EMR) data to generate insights. OBJECTIVE: The aim of this study was to extract EMR data pertaining to bariatric patient information as a means to explore predictive factors of weight loss post-bariatric surgery. METHODS: We conducted a retrospective cohort study of patients undergoing bariatric surgery between January 1, 2018, and April 30, 2019, at Humber River Hospital. Multiple linear regression was used to examine whether age, pre-surgery body mass index (BMI), comorbidities and mental health disorders predicted higher weight loss 6 months following bariatric surgery. RESULTS: A total of 502 patients were included in the final analysis. Age (ß = 0.04 [95% CI 0.01, 0.06], p = 0.005), baseline BMI (ß = -0.16 [95% CI -0.19, -0.13], p = <0.0001) and diabetes (ß = 0.82 [95% CI 0.23, 1.42], p = 0.007) were associated with weight loss six months post-bariatric surgery. CONCLUSION: EMRs are a rich source of data with the potential to generate insights that can lead to improved care.

Physician Experience with Electronic Order Sets.

BACKGROUND: Electronic medical record (EMR) and electronic health record (EHR) are used interchangeably to describe a computerized medical information system that collects, stores and displays patient information (Boonstra and Broekhuis 2010). Blumenthal and Tavenner (2010) suggested that computerized medical implementation improves decision-making and patient management. As part of its EMR, Humber River Hospital has implemented electronic order sets (EOSs) by building them into the computerized physician order entry (CPOE) system. Electronic prescribing renders paper prescriptions obsolete as it reduces errors; increases accuracy; and enhances efficiency, compliance and record-keeping (Canada Health Infoway 2017). OBJECTIVE: The aim of this research was to explore physicians' perspectives and experiences using EOSs. METHODS: This qualitative study examined the perceptions of various physicians on the impact of EOSs. Data were collected through semi-structured, in-depth interviews with eligible physicians. Domains explored included usability, efficiency, safety and implications for the physician profession. RESULTS: Major themes that emerged included usability, efficiency and safety. Several implications for physician practice were also revealed. CONCLUSION: The findings from our study support previous studies that describe the benefits of EOSs, including ease of use and efficiency, real-time information that is evidence-based, increased safety and minimization of memory burden. EOSs were not perceived to be a replacement for clinical reasoning.

The Impact of a Real-Time Locating System within the Perioperative Environment on Physicians and Patients' Families.

BACKGROUND: Humber River Hospital has implemented a real-time location system (RTLS) within the operating room in order to provide real-time information about patients' status and manage the many components involved during the perioperative journey. OBJECTIVE: The aim of this study was to explore both physicians' and family members' perceptions of the functionality and efficiency of the RTLS within the perioperative environment. METHODS: Semi-structured interviews were conducted with physicians and patients' family members to elicit various perspectives regarding the use of RTLSs throughout the perioperative process. Interviews were recorded and transcribed to extract key themes. RESULTS: Three themes gleaned from physician interviews were system weaknesses, perceptions of potential benefit, and benefits to family members. Three themes uncovered from family member interviews included convenience, ameliorating anxiety, and reducing interruptions. CONCLUSION: Overall, physicians reported that the RTLS had potential to enhance workflow but that significant improvement regarding its implementation and use was needed to reach its full benefit. Family members were unanimous that it provides them with all the tracking information they desire.

Smartphone Technology: Impact on Interprofessional Working Relations between Doctors and Nurses.

BACKGROUND: For decades, the main communication technology in hospitals has been the paging system. In the era of digital communication, smartphones have been adopted by hospitals seeking to modernize processes and offer real-time, two-way communication to increase efficiency. OBJECTIVE: The aim of this study was to explore physicians' and nurses' perceptions of the impact of smartphones on communication and efficiency. METHODS: Mann-Whitney U-tests were used to compare differences in item scores between physicians and nurses on 17 questionnaire items relating to smartphone impact on interpersonal relationships and communication, efficiency and reliability. An open-ended question was used to elicit additional feedback. RESULTS: In total, 43 nurses and 27 physicians participated in the study. Nurses' ratings were significantly higher than physicians' on a number of questionnaire items, including the following: smartphones have a positive impact on efficiency (Mdn = 4.0 vs. 3.0, U = 321.0, p = 0.027, r = .33), smartphones increase my accessibility to physicians (Mdn = 5.0 vs. 3.0, U = 277.0, p = 0.009, r = 0.42) and smartphones reduce interruptions versus pagers (Mdn = 4.0 vs. 2.0, U = 224.0, p > 0.0001, r = 0.47). CONCLUSION: The findings suggest that smartphone technology may reduce the locus of control for physicians, potentially limiting their ability to prioritize patients' needs and manage workflow efficiently.

A Narrative Study on the Impact of Information and Communication Technology on the Relationship between Patients and Medical Learners.

BACKGROUND: Current medical learners are immersed in an era of tremendous technological advancements. Consequently, the use of information and communication technologies (ICTs) might impact entrustable professional activities (EPAs), such as interpersonal and communication skills between learners and patients. OBJECTIVE: The aim of this study was to explore medical learners' perspectives on ICTs and its impact on the relationship between them and their patients. METHODS: Semi-structured interviews were conducted with medical learners to elicit their perspectives regarding ICTs in a clinical setting. Interviews were recorded, transcribed and analyzed to identify key themes. RESULTS: Participants reported that ICTs implementation improved quality of care by allowing for rapid access to patient information and facilitating clinical decision making. However, technology use created a potential challenge to forging empathy toward patients and developing a rapport with them. CONCLUSION: It is paramount to devise safeguards or milestone requirements in student evaluations for graduation.

Using Structurally Well-Defined Norbornyl-Bridged Acene Dimers to Map a Mechanistic Landscape for Correlated Triplet Formation in Singlet Fission.

Structurally well-defined TIPS-acetylene substituted tetracene (TIPS-BT1') and pentacene (TIPS-BP1') dimers utilizing a [2.2.1] bicyclic norbornyl bridge have been studied-primarily using time-resolved spectroscopic methods-to uncover mechanistic details about primary steps in singlet fission leading to formation of the biexcitonic 1TT state as well as decay pathways to the ground state. For TIPS-BP1' in room-temperature toluene, 1TT formation is rapid and complete, occurring in 4.4 ps. Decay to the ground state in 100 ns is the primary loss pathway for 1TT in this system. For TIPS-BT1', the 1TT is also observed to form rapidly (with a time constant of 5 ps), but in this case it occurs in concert with establishment of an excited-state equilibrium ( K ∼ 1) with the singlet exciton state S1 at an energy of 2.3 eV above the ground state. The equilibrated states survive for 36 ns and are lost to ground state through both radiative and nonradiative pathways via the S1 and nonradiative pathways via the 1TT. The rapidity of 1TT formation in TIPS-BT1' is at first glance surprising. However, our analysis suggests that the few-parameter rate constant expression of Marcus theory explains both individual and comparative findings in the set of systems, thus establishing benchmarks for diabatic coupling and reorganization energy needed for efficient 1TT formation. Finally, a comparison of TIPS-BT1' with previous results obtained for a close constitutional isomer (TIPS-BT1) differing in the placement of TIPS-acetylene side groups suggests that the magnitude of exchange interaction in the correlated triplet manifold plays a critical role dictating 1TT yield in the tetracenic systems.

Sofosbuvir-Based Therapy in Hepatitis C Virus-Infected Cancer Patients: A Prospective Observational Study.

BACKGROUND: Data are sparse on treatment of chronic hepatitis C virus (HCV) in cancer patients. We evaluated the efficacy and safety of sofosbuvir-based therapy (SOFBT) in cancer patients. METHODS: Patients treated with SOFBT at our center during 2014-2017 were included in a prospective observational study. Efficacy [sustained virologic response at 12 weeks after the end of treatment (SVR12)], cancer-related outcomes and adverse events (AEs) were assessed. RESULTS: We included 153 patients. Most were men (109; 71%), white (92; 60%), non-cirrhotic (105; 69%), and with HCV genotype 1 (110; 72%). The most common cancers were hepatocellular carcinoma (HCC) (27; 18%) and multiple myeloma (14; 9%). The overall SVR12 rate was 91% (128/141). SVR12 was 100% in patients treated with ledipasvir/sofosbuvir for 8 weeks. Of the 32 patients initially excluded from cancer clinical trials because of HCV, 27 (84%) were granted cancer therapy access after starting SOFBT. Six patients with indolent non-Hodgkin's lymphoma (NHL) received SOFBT without cancer treatment. Two achieved complete remission, one had partial remission, and two had stable cancer. Within 6 months after SOFBT, 5% (6/121) of patients in remission or with stable cancer, had progression or recurrence (two with HCC and one each with esophageal cancer, cholangiocarcinoma, NHL, and tonsillar cancer). No de novo HCCs occurred. AEs were most commonly grade 1-2 (90%). CONCLUSIONS: SOFBT in HCV-infected cancer patients is effective and safe, may permit access to investigational cancer therapy expanding treatment options, may induce remission of NHL, and may be used for 8 weeks.

Synthesis of Geometrically Well-Defined Covalent Acene Dimers for Mechanistic Exploration of Singlet Fission.

We report the first synthesis of norbornyl-bridged acene dimers (2 and 3) with well-defined and controlled spatial relationships between the acene chromophore subunits. We employ a modular 2-D strategy wherein the central module, common to all our compounds, is a norbornyl moiety. The acenes are attached to this module using the Diels-Alder reaction, which also forms one of the acene rings. Manipulation of the Diels-Alder adducts provides the desired geometrically defined bis-acenes. The modular nature of this synthesis affords flexibility and allows for the preparation of a variety of acene dimers, including functionalized tetracene dimers.