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Commercially available performance-enhancing supplements can contain banned performance-enhancing drugs (PEDs) and undisclosed steroid hormones that can induce hormonal abnormalities with associated clinical signs. We present a case of a 40-year-old male who developed bilateral gynecomastia and biochemical hypogonadotropic hypogonadism with a corresponding 6-month history of consuming commercially available performance-enhancing supplements for gym workouts. These performance-enhancing supplements were found to contain amounts of RAD-140, a selective androgen receptor modulator, MK-677, a GH secretagogue and cardarine, all of which are banned PEDs. In vitro analysis also detected undisclosed hormones testosterone, estradiol, and GH in all 3 supplements, with further steroid analysis using liquid chromatography mass spectrometry identifying an unidentified compound coeluting close to the testosterone peak. Cessation of these supplements led to full resolution of symptoms including normalization of hypogonadotropic hypogonadism. This case highlights the need for clinicians to consider commercially available performance-enhancing supplements as potential sources of PEDs and exogenous steroid hormones that can have adverse clinical consequences.
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Neoplasias Colorretais , DNA Polimerase III , DNA Polimerase II , Inibidores de Checkpoint Imunológico , Proteínas de Ligação a Poli-ADP-Ribose , Humanos , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Inibidores de Checkpoint Imunológico/uso terapêutico , DNA Polimerase II/genética , DNA Polimerase II/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/genética , DNA Polimerase III/genética , DNA Polimerase III/metabolismo , MutaçãoRESUMO
BACKGROUND AND OBJECTIVES: Childbirth is mainly thought to be a woman's concern, and mortality can be prevented by making a birth plan constituting birth preparedness and complication readiness with the entire family as one unit. Indian National Plans aim to increase male involvement, but the policies lack directions and monitoring systems; hence, it becomes important to address this issue. METHODOLOGY: A cross-sectional study conducted in a rural hospital and a community-based setup included 350 male participants, consisting of new fathers or expecting fathers, who were interviewed with the help of a questionnaire. RESULTS: Only 28.29% of male participants were well involved in the process of birth preparedness and complication readiness. 83% of the husbands accompanied their respective wives during ANC visits (mean number of visits: 5.76). 33% of males were aware of various danger signs and complications related to pregnancy. The males with better education (p-value < 0.005) and economic status (p-value < 0.0001) had better birth preparedness. Several variables in the study were positively correlated with the amount of money saved. Interpretation and conclusion: Male involvement during pregnancy significantly impacts maternal and child health outcomes. However, this study highlights a lack of awareness and involvement among males. We strongly recommend enhancing existing maternal and child health (MCH) programs to include components focused on male partner engagement in birth preparedness, complication readiness, and obstetric emergencies.
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BACKGROUND: Oral SERDs are a novel drug class that have been developed to counteract resistance due to ESR1 mutations. Several SERDs have emerged from phase 2 and 3 trials, with the FDA limiting approval for Elacestrant to patients with ESR1mt tumours despite PFS benefit in the overall population. However, questions remain on whether patients with ESR1wt tumours stand to benefit from oral SERDs. PATIENTS AND METHODS: Manuscripts and conference presentations of Randomised Controlled Trials were extracted after a systematic search of Embase, PubMed and Cochrane from inception until January 21,2023. RCTs investigating the efficacy of oral SERDs versus endocrine therapy for ER positive, HER2 negative advanced breast cancer, and which reported the Kaplan Meier (KM) curves of PFS in the overall and ESR1 mutant (ESR1mt) population were selected. A graphical reconstructive algorithm was applied to estimate time-to-event outcomes from reported KM curves in all overall and ESR1mt cohorts. A bipartite matching algorithm, KMSubtraction, was used to derive survival data for unreported (ESR1wt) subgroups. An individual patient data (IPD) meta-analysis was then pursued, pooling data by ESR1 mutation status in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Cochrane Guidelines for IPD. RESULTS: The randomized clinical trials ACELERA, AMEERA-3, EMERALD and SERENA-2 were included, totalling 1290 patients. In the pooled analysis of the overall cohort, PFS benefit was observed with oral SERDs when compared with treatment of physicians choice (TPC) (HR 0.783, 95%CI 0.681-0.900, p<0.001). In the ESR1mt subgroup, oral SERDs demonstrated improved PFS (HR 0.557, 95%CI 0.440-0.705, p<0.001) compared to TPC. In the ESR1wt subgroup, oral SERDs demonstrated no significant PFS benefit (HR 0.944, 95%CI 0.783-1.138, p=0.543) when compared to TPC. CONCLUSIONS: The results of this IPD meta-analysis suggests that PFS benefit in the overall population is mainly driven by the ESR1mt subgroup.
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Background and objectives Endothelial soluble lectin-type oxidized low-density lipoprotein receptor 1 (sLOX-1) recognizes oxidized low-density lipoprotein (LDL) and triggers downstream signaling leading to atherosclerosis. The objective of this study was to demonstrate the utility of sLOX-1 as a biomarker for detecting acute myocardial infarction (MI) and stable angina (SA) and to develop a diagnostic algorithm for distinguishing coronary vasospasm from coronary plaque rupture. Methods We enrolled 62 patients who underwent diagnostic coronary angiography (CAG) and 30 healthy controls (21 men and nine women) and measured sLOX-1, troponin I, and cardiac myosin-binding protein C (c-MyBPC) using commercial kits. Results Patients with MI exhibited higher sLOX-1 levels (301.55 ± 196.16 pg/ml) than patients with stable angina (220.76 ± 103.65 pg/ml) and healthy controls (121.14 ± 77.10, F: 10.55, p<0.001). Although higher troponin I levels were detected in MI patients (263.00 ± 493.00 vs. 3.19 ± 2.15 ng/ml, p=0.0019), no significant elevation was observed in SA patients (1.91 ± 0.79 ng/ml). Plasma sLOX-1 levels showed a positive association with age (r=0.37, p=0.003), but not with gender (r=0.04, p=0.75). Troponin I showed no association with age (r=0.12, p=0.36) or gender (r=0.06, p=0.62). Receiver operating characteristic (ROC) curves revealed that among the three biomarkers, troponin-I showed a higher area under the curve (AUC) (AUC: 0.941), followed by sLOX-1 (AUC: 0.888), while c-MyBPC showed no clinical utility in the detection of MI (AUC: 0.666). Conclusions A marked elevation of sLOX-1 can detect MI and differentiate the presence or absence of plaque rupture, along with diagnosing stable angina.
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The body axis of vertebrate embryos is periodically subdivided into 3D multicellular units called somites. While genetic oscillations and molecular prepatterns determine the initial length-scale of somites, mechanical processes have been implicated in setting their final size and shape. To better understand the intrinsic material properties of somites, a method is developed to culture single-somite explant from zebrafish embryos. Single somites are isolated by first removing the skin of embryos, followed by yolk removal and sequential excision of neighboring tissues. Using transgenic embryos, the distribution of various sub-cellular structures can be observed by fluorescent time-lapse microscopy. Dynamics of explanted somites can be followed for several hours, thus providing an experimental framework for studying tissue-scale shape changes at single-cell resolution. This approach enables direct mechanical manipulation of somites, allowing for dissection of the material properties of the tissue. Finally, the technique outlined here can be readily extended for explanting other tissues such as the notochord, neural plate, and lateral plate mesoderm.
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Somitos , Peixe-Zebra , Animais , Mesoderma , Notocorda , Somitos/cirurgiaRESUMO
The body axis of vertebrate embryos is periodically segmented into bilaterally symmetric pairs of somites1,2. The anteroposterior length of somites, their position and left-right symmetry are thought to be molecularly determined before somite morphogenesis3,4. Here we show that, in zebrafish embryos, initial somite anteroposterior lengths and positions are imprecise and, consequently, many somite pairs form left-right asymmetrically. Notably, these imprecisions are not left unchecked and we find that anteroposterior lengths adjust within an hour after somite formation, thereby increasing morphological symmetry. We find that anteroposterior length adjustments result entirely from changes in somite shape without change in somite volume, with changes in anteroposterior length being compensated by corresponding changes in mediolateral length. The anteroposterior adjustment mechanism is facilitated by somite surface tension, which we show by comparing in vivo experiments and in vitro single-somite explant cultures using a mechanical model. Length adjustment is inhibited by perturbation of molecules involved in surface tension, such as integrin and fibronectin. By contrast, the adjustment mechanism is unaffected by perturbations to the segmentation clock, therefore revealing a distinct process that influences morphological segment lengths. We propose that tissue surface tension provides a general mechanism to adjust shapes and ensure precision and symmetry of tissues in developing embryos.
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Somitos , Peixe-Zebra , Animais , Padronização Corporal , Desenvolvimento Embrionário , Morfogênese , Tensão Superficial , Proteínas de Peixe-Zebra/genéticaRESUMO
The mesothelium lines body cavities and surrounds internal organs, widely contributing to homeostasis and regeneration. Mesothelium disruptions cause visceral anomalies and mesothelioma tumors. Nonetheless, the embryonic emergence of mesothelia remains incompletely understood. Here, we track mesothelial origins in the lateral plate mesoderm (LPM) using zebrafish. Single-cell transcriptomics uncovers a post-gastrulation gene expression signature centered on hand2 in distinct LPM progenitor cells. We map mesothelial progenitors to lateral-most, hand2-expressing LPM and confirm conservation in mouse. Time-lapse imaging of zebrafish hand2 reporter embryos captures mesothelium formation including pericardium, visceral, and parietal peritoneum. We find primordial germ cells migrate with the forming mesothelium as ventral migration boundary. Functionally, hand2 loss disrupts mesothelium formation with reduced progenitor cells and perturbed migration. In mouse and human mesothelioma, we document expression of LPM-associated transcription factors including Hand2, suggesting re-initiation of a developmental program. Our data connects mesothelium development to Hand2, expanding our understanding of mesothelial pathologies.
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Mesotelioma , Peixe-Zebra , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Epitélio/metabolismo , Mesotelioma/genética , Camundongos , Fatores de Transcrição/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
To extract the melanin pigment from marine microbes and their biological potential, the present study was done. Isolation and identification of the melanin-producing Nocardiopsis sp. were obtained from the sediment samples. Zone of inhibition and minimal inhibitory concentration test was performed using melanin. Melanin was extracted from sediment-associated marine Nocardiopsis sp. In the present study, marine actinobacterium was identified by the conventional method, and the isolate was identified as Nocardiopsis sp. Melanin was extracted, and antibacterial activities were performed against different pathogens and the highest zone of inhibition is more in the E. coli while related to another two species. From previous observation done by Fu et al., they have said that marine actinobacteria have the ability of antimicrobial activity, which is very much helpful in producing the potential antimicrobial drugs this was similar to our study that marine actinobacteria have the capability to produce melanin pigment, and at the same time, it helps as to show the antibacterial activity. We concluded that melanin is produced by the Nocardiopsis sp. We also found that melanin extracted from the Nocardiopsis sp. of marine actinobacterium also has an antibacterial effect.
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In response to the coronavirus (COVID-19) pandemic, Government and public health authorities around the world are developing contact tracing apps as a way to trace and slow the unfold of the virus. There is major divergence among nations, however, between a "privacy-first" approach that protects citizens' information at the price of very restricted access for public health authorities and a "data-first" approach that stores massive amounts of knowledge that, whereas of immeasurable price to epidemiologists. Contact tracing apps work by gathering information from people who have tested positive for the virus and so locating and notifying individuals with whom those people are in shut contact, oftentimes by use of GPS, Bluetooth, or wireless technology. All of the user's information is employed and picked up, the study found that users' information would be created anonymous, encrypted, secured, and can be transmitted on-line and stored solely in an aggregated format. Contact tracing apps use either a centralized or a decentralized approach to work the user's information. Apps that use a centralized approach have high privacy risks. In this paper, the researcher's contributions related to the security and privacy of Contact tracing apps have been discussed and, later research gaps have been identified with proposed solutions.
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Hemofilia A/genética , MicroRNAs/metabolismo , Núcleo Celular/metabolismo , Citoplasma/metabolismo , RNA Helicases DEAD-box/metabolismo , Genótipo , Humanos , MicroRNAs/genética , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , Ribonuclease III/genética , Ribonuclease III/metabolismoRESUMO
Whole saliva is mainly composed of fluid produced by major and minor salivary glands. Major salivary glands including parotid, submandibular, and sublingual glands, are known to secrete fluid transported from serum as well as surrounding glandular tissues [1]. Beside the secretions from salivary glands, oral mucosa, periodontium, as well as oral microflora also contribute to the final content of whole saliva [1]. Whole saliva therefore represents a complex balance among local and systemic sources [2]. This allows for the application of saliva in the diagnosis not only for salivary gland disorders but also for oral diseases and systemic conditions [2]. The role of saliva as a diagnostic tool in detecting Oral Squamous Cell Carcinoma. Articles published in PUBMED, EMBASE, COCHRANE, GOOGLE, manual search and back references of the articles for last 5 years extracted 77 articles. Studies which considered saliva as a diagnostic tool were included. Statistical analysis with Receivers Operating Curve to establish sensitivity and specificity of the salivary biomarkers as a diagnostic tool to detect Oral Squamous Cell Carcinoma were included for meta analysis. The measure of effect with 95% confidence interval were meta analysed for 9 articles in which 308 healthy individuals compared with 340 patients with Oral Squamous Cell Carcinoma. Highly sensitive salivary biomarkers for detecting Oral Squamous Cell Carcinoma were MMP-9, Chemerin, Choline + Betaine + Pipecolinic Acid + I - Carnitine(confidence interval ranges from 0.83-1.0). The narrow confidence interval of 0.95 + (0.88-1.00) was seen for MMP-9 followed by 1.00 + (0.78-1.00) for chemerin. Highly specific biomarkers for Oral Squamous Cell Carcinoma were MMP-9 (specificity -100%,), Chemerin(specificity-100%), over expressed mi RNA 136 with specificity of 0.88(0.69-0.97), under expressed mi RNA 27B with specificity of 1.0(0.66-1.00). Saliva can be used as a diagnostic tool with highly sensitive and specific markers namely MMP-9, Chemerin for early detection of Oral Squamous Cell Carcinoma.
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Biomarcadores Tumorais/análise , Neoplasias Bucais/diagnóstico , Saliva/química , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico , Quimiocinas/análise , Quimiocinas/biossíntese , Detecção Precoce de Câncer/métodos , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/análise , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Metaloproteinase 9 da Matriz/análise , Metaloproteinase 9 da Matriz/biossíntese , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Utilization of alternative transcription start sites through alterations in epigenetic promoter regions causes reduced expression of immunogenic N-terminal peptides, which may facilitate immune evasion in early gastric cancer. We hypothesized that tumors with high alternate promoter utilization would be resistant to immune checkpoint inhibition in metastatic gastric cancer. PATIENTS AND METHODS: Two cohorts of patients with metastatic gastric cancer treated with immunotherapy were analyzed. The first cohort (N = 24) included patients treated with either nivolumab or pembrolizumab. Alternate promoter utilization was measured using the NanoString® (NanoString Technologies, Seattle, WA, USA) platform on archival tissue samples. The second cohort was a phase II clinical trial of patients uniformly treated with pembrolizumab (N = 37). Fresh tumor biopsies were obtained, and transcriptomic analysis was carried out on RNAseq data. Alternate promoter utilization was correlated to T-cell cytolytic activity, objective response rate and survival. RESULTS: In the first cohort 8 of 24 (33%) tumors were identified to have high alternate promoter utilization (APhigh), and this was used to define the APhigh tertile of the second cohort (13 APhigh of 37). APhigh tumors exhibited decreased markers of T-cell cytolytic activity and lower response rates (8% versus 42%, P = 0.03). Median progression-free survival was lower in the APhigh group (55 versus 180 days, P = 0.0076). In multivariate analysis, alternative promoter utilization was an independent predictor of immunotherapy survival [hazard ratio 0.29, 95% confidence interval 0.099-0.85, P = 0.024). Analyzing tumoral evolution through paired pre-treatment and post-treatment biopsies, we observed consistent shifts in alternative promoter utilization rate associated with clinical response. CONCLUSION: A substantial proportion of metastatic gastric cancers utilize alternate promoters as a mechanism of immune evasion, and these tumors may be resistant to anti-PD1 immune checkpoint inhibition. Alternate promoter utilization is thus a potential mechanism of resistance to immune checkpoint inhibition, and a novel predictive biomarker for immunotherapy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT#02589496.
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Epigenômica , Receptor de Morte Celular Programada 1/genética , Regiões Promotoras Genéticas/genética , Neoplasias Gástricas/tratamento farmacológico , Anticorpos Monoclonais Humanizados/administração & dosagem , Sequência de Bases/efeitos dos fármacos , Biópsia , Humanos , Imunoterapia , Metástase Neoplásica , Nivolumabe/administração & dosagem , Intervalo Livre de Progressão , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Linfócitos T/efeitos dos fármacos , Sítio de Iniciação de Transcrição/efeitos dos fármacosRESUMO
Background: We have previously shown that raised p-S6K levels correlate with resistance to chemotherapy in ovarian cancer. We hypothesised that inhibiting p-S6K signalling with the dual m-TORC1/2 inhibitor in patients receiving weekly paclitaxel could improve outcomes in such patients. Patients and methods: In dose escalation, weekly paclitaxel (80 mg/m2) was given 6/7 weeks in combination with two intermittent schedules of vistusertib (dosing starting on the day of paclitaxel): schedule A, vistusertib dosed bd for 3 consecutive days per week (3/7 days) and schedule B, vistusertib dosed bd for 2 consecutive days per week (2/7 days). After establishing a recommended phase II dose (RP2D), expansion cohorts in high-grade serous ovarian cancer (HGSOC) and squamous non-small-cell lung cancer (sqNSCLC) were explored in 25 and 40 patients, respectively. Results: The dose-escalation arms comprised 22 patients with advanced solid tumours. The dose-limiting toxicities were fatigue and mucositis in schedule A and rash in schedule B. On the basis of toxicity and pharmacokinetic (PK) and pharmacodynamic (PD) evaluations, the RP2D was established as 80 mg/m2 paclitaxel with 50 mg vistusertib bd 3/7 days for 6/7 weeks. In the HGSOC expansion, RECIST and GCIG CA125 response rates were 13/25 (52%) and 16/25 (64%), respectively, with median progression-free survival (mPFS) of 5.8 months (95% CI: 3.28-18.54). The RP2D was not well tolerated in the SqNSCLC expansion, but toxicities were manageable after the daily vistusertib dose was reduced to 25 mg bd for the following 23 patients. The RECIST response rate in this group was 8/23 (35%), and the mPFS was 5.8 months (95% CI: 2.76-21.25). Discussion: In this phase I trial, we report a highly active and well-tolerated combination of vistusertib, administered as an intermittent schedule with weekly paclitaxel, in patients with HGSOC and SqNSCLC. Clinical trial registration: ClinicialTrials.gov identifier: CNCT02193633.
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Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Benzamidas/administração & dosagem , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/patologia , Morfolinas/administração & dosagem , Neoplasias Ovarianas/tratamento farmacológico , Inibidores de Proteínas Quinases/administração & dosagem , Pirimidinas/administração & dosagem , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Benzamidas/efeitos adversos , Benzamidas/farmacocinética , Carcinoma Pulmonar de Células não Pequenas/patologia , Esquema de Medicação , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Masculino , Dose Máxima Tolerável , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 2 de Rapamicina/antagonistas & inibidores , Pessoa de Meia-Idade , Morfolinas/efeitos adversos , Morfolinas/farmacocinética , Neoplasias Ovarianas/patologia , Paclitaxel/administração & dosagem , Paclitaxel/efeitos adversos , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/farmacocinética , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Critérios de Avaliação de Resposta em Tumores Sólidos , Proteínas Quinases S6 Ribossômicas/metabolismoRESUMO
AIMS: Advanced biliary tract carcinomas (ABC) are malignancies with limited effective therapies for advanced disease. There is little published evidence of outcomes of ABC patients participating in phase I clinical trials. MATERIALS AND METHODS: Patient characteristics, treatment details and outcomes of ABC patients treated at a dedicated phase I unit were captured and analysed from case and trial records. RESULTS: In total, 123 ABC patients were included in the study, of which 48 patients participated in 41 different phase I trials; 75 (61%) did not participate due to rapid disease progression or patient choice. Molecular characterisation of tumours using a targeted panel was conducted in 15 (31%), yielding several potentially actionable mutations, including BRCA, PIK3CA, FGFR, AKT and PTEN loss. Of the 39 evaluable patients there was one exceptional responder. Eighteen (46%) other patients achieved stable disease as their best response, with a clinical benefit rate at 4 months of 10%. Treatment was generally well tolerated with grade 3 or 4 adverse events only observed in eight patients (17 %), of which six were drug related and led to trial discontinuation in one (3%), with no toxicity-related deaths. CONCLUSION: Carefully selected ABC patients have been found to tolerate experimental phase I clinical trials without excess toxicity. The aggressive nature of this disease warrants consideration of early referral to a phase I unit. Future work will require comprehensive molecular profiling in an attempt to understand the biology underlying the exceptional responders and to match patients in real-time to targeted therapies.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Biliar/tratamento farmacológico , Idoso , Ensaios Clínicos Fase I como Assunto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
Eukaryotic cells undergo shape changes during their division and growth. This involves flow of material both in the cell membrane and in the cytoskeletal layer beneath the membrane. Such flows result in redistribution of phospholipid at the cell surface and actomyosin in the cortex. Here we focus on the growth of the intercellular surface during cell division in a Caenorhabditis elegans embryo. The growth of this surface leads to the formation of a double-layer of separating membranes between the two daughter cells. The division plane typically has a circular periphery and the growth starts from the periphery as a membrane invagination, which grows radially inward like the shutter of a camera. The growth is typically not concentric, in the sense that the closing internal ring is located off-center. Cytoskeletal proteins anillin and septin have been found to be responsible for initiating and maintaining the asymmetry of ring closure but the role of possible asymmetry in the material flow into the growing membrane has not been investigated yet. Motivated by experimental evidence of such flow asymmetry, here we explore the patterns of internal ring closure in the growing membrane in response to asymmetric boundary fluxes. We highlight the importance of the flow asymmetry by showing that many of the asymmetric growth patterns observed experimentally can be reproduced by our model, which incorporates the viscous nature of the membrane and contractility of the associated cortex.
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Membrana Celular/metabolismo , Citocinese , Movimento , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/embriologia , Modelos BiológicosRESUMO
Interaction forces between aromatic moieties, often referred to as π-π interactions, are an important element in stabilizing complex supramolecular structures. For supramolecular self-assembly occurring on surfaces, where aromatic moieties are typically forced to adsorb coplanar with the surface, the possible role of intermolecular aromatic interactions is much less explored. Here, we report on unusual, ring-shaped supramolecular corral surface structures resulting from adsorption of a molecule with nonplanar structure, allowing for intermolecular aromatic interactions. The discrete corral structures are observed using high-resolution scanning tunneling microscopy, and the energetic driving forces for their formation are elucidated using density functional theory calculations and Monte Carlo simulations. The individual corrals involve between 11 and 18 molecules bound through triazole moieties to a ring-shaped ensemble of bridge site positions on (111) surfaces of copper, silver, or gold. The curvature required to form the corrals is identified to result from the angle dependence of aromatic interactions between molecular phenanthrene moieties. The study provides detailed quantitative insights into triazole-surface and aromatic interactions and illustrates how they may be used to drive surface supramolecular self-assembly.
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Molecular motors, highly efficient biological nanomachines, hold the potential to be employed for a wide range of nanotechnological applications. Toward this end, kinesin, dynein, or myosin motor proteins are commonly surface-immobilized within engineered environments in order to transport cargo attached to cytoskeletal filaments. Being able to flexibly control the direction of filament motion, and in particular on planar, non-topographical surfaces, has, however, remained challenging. Here, we demonstrate the applicability of a UV-laser-based ablation technique to programmably generate highly localized patterns of functional kinesin-1 motors with different shapes and sizes on PLL-g-PEG-coated polystyrene surfaces. Straight and curved motor tracks with widths of less than 500 nm could be generated in a highly reproducible manner and proved to reliably guide gliding microtubules. Though dependent on track curvature, the characteristic travel lengths of the microtubules on the tracks significantly exceeded earlier predictions. Moreover, we experimentally verified the performance of complex kinesin-1 patterns, recently designed by evolutionary algorithms for controlling the global directionality of microtubule motion on large-area substrates.