Biologically Active Micropatterns of Biomolecules and Living Matter Using Microbubble Lithography.

In situ patterning of biomolecules and living organisms while retaining their biological activity is extremely challenging, primarily because such patterning typically involves thermal stresses that could be substantially higher than the physiological thermal or stress tolerance level. Top-down patterning approaches are especially prone to these issues, while bottom-up approaches suffer from a lack of control in developing defined structures and the time required for patterning. A microbubble generated and manipulated by optical tweezers (microbubble lithography) is used to self-assemble and pattern living organisms in continuous microscopic structures in real-time, where the material thus patterned remains biologically active due to their ability to withstand elevated temperatures for short exposures. Successful patterns of microorganisms (Escherichia coli, Lactococcus. lactis and the Type A influenza virus) are demonstrated, as well as reporter proteins such as green fluorescent protein (GFP) on functionalized substrates with high signal-to-noise ratio and selectivity. Together, the data presented herein may open up fascinating possibilities in rapid in situ parallelized diagnostics of multiple pathogens and bioelectronics.

Deciphering the Dilemma: Anticoagulation for Heart Failure With Preserved Ejection Fraction (HFpEF).

Impairment in ventricular relaxation and preserved left ventricular ejection fraction are the two main features of heart failure with preserved ejection fraction (HFpEF) a difficult clinical condition. Therapeutic choices for HFpEF patients are still scarce despite its rising frequency and negative effects on morbidity and mortality, necessitating creative methods to enhance results. The increased thromboembolic risk seen in these individuals raises questions about the relevance of anticoagulation in the therapy of HFpEF. Although anticoagulation has been shown to be beneficial in heart failure with decreased ejection fraction (HFrEF) and other high-risk cardiovascular disorders, its efficacy and safety in HFpEF present a challenging therapeutic challenge. Anticoagulants have been the subject of clinical trials in HFpEF, but the results have been conflicting, giving clinicians only a little information with which to make decisions. The decision-making process is made more difficult by worries about potential bleeding hazards, particularly in susceptible elderly HFpEF patients with other comorbidities. The link between heart failure and anticoagulant medication in HFpEF is thoroughly analyzed in this narrative review. In HFpEF, cardiac fibrosis and endothelial dysfunction create a prothrombotic milieu, as is highlighted in this passage. Also covered are recent developments in innovative biomarker research and cutting-edge imaging techniques, which may provide ways to spot HFpEF patients who might benefit from anticoagulation. This therapeutic conundrum may be resolved by using precision medicine strategies based on risk classification and individualized therapy choices. This review emphasizes the need for more research to establish the best use of anticoagulation in HFpEF within the framework of personalized therapy and shared decision-making. To successfully manage thromboembolic risk and reduce bleeding consequences in HFpEF patients, it is essential to perform well-designed clinical studies and advance our understanding of the pathophysiology of HFpEF. These developments may ultimately improve the prognosis and quality of life for people who suffer from this difficult and mysterious ailment.

Directed Self-Assembly Driven Mesoscale Lithography Using Laser-Induced and Manipulated Microbubbles: Complex Architectures and Diverse Applications.

A microbubble nucleated due to the absorption of a tightly focused laser at the interface of a liquid-solid substrate enables directed and irreversible self-assembly of mesoscopic particles dispersed in the liquid at the bubble base. This phenomenon has facilitated a new microlithography technique which has grown rapidly over the past decade and can now reliably pattern a vast range of soft materials and colloids, ranging from polymers to metals to proteins. In this review, we discuss the science behind this technology and the present state-of-the-art. Thus, we describe the physics of the self-assembly driven by the bubble, the techniques for generating complex mesoarchitectures, both discrete and continuous, and their properties, and the various applications demonstrated in plastic electronics, site-specific catalysis, and biosensing. Finally, we describe a roadmap for the technique to achieve its potential of successfully patterning "everything" mesoscopic and the challenges that lie therein.

Novel 18F-Labeled Radioligands for Positron Emission Tomography Imaging of Myelination in the Central Nervous System.

Myelin is the protective sheath that surrounds nerves in vertebrates to protect axons, which thereby facilitates impulse conduction. Damage to myelin is associated with many neurodegenerative diseases such as multiple sclerosis and also includes spinal cord injury (SCI). The small size of the spinal cord poses formidable challenges to in vivo monitoring of myelination, which we investigated via conducting a structure-activity relationship study to determine the optimum positron-emitting agent to use for imaging myelin using positron emission tomography (PET). From these studies, [18F]PENDAS was identified as the lead agent to use in conjunction with PET imaging to delineate the integrity of spinal cord myelin. A subsequent in vivo PET imaging study of [18F]PENDAS in rats with SCI showed promising pharmacokinetic results that justify further development of imaging markers for diagnosing myelin-related diseases. Additionally, [18F]PENDAS could be valuable in determining the efficacy of therapies that are currently under development.

Inhibition of novel GCN5-ATM axis restricts the onset of acquired drug resistance in leukemia.

Leukemia is majorly treated by topoisomerase inhibitors that induce DNA double strand breaks (DSB) resulting in cell death. Consequently, modulation of DSB repair pathway renders leukemic cells resistant to therapy. As we do not fully understand the regulation of DSB repair acquired by resistant cells, targeting these cells has been a challenge. Here we investigated the regulation of DSB repair pathway in early drug resistant population (EDRP) and late drug resistant population (LDRP). We found that doxorubicin induced equal DSBs in parent and EDRP cells; however, cell death is induced only in the parent cells. Further analysis revealed that EDRP cells acquire relaxed chromatin via upregulation of lysine acetyl transferase KAT2A (GCN5). Drug treatment induces GCN5 interaction with ATM facilitating its recruitment to DSB sites. Hyperactivated ATM maximize H2AX, NBS1, BRCA1, Chk2, and Mcl-1 activation, accelerating DNA repair and survival of EDRP cells. Consequently, inhibition of GCN5 significantly reduces ATM activation and survival of EDRP cells. Contrary to EDRP, doxorubicin failed to induce DSBs in LDRP because of reduced drug uptake and downregulation of TOP2ß. Accordingly, ATM inhibition prior to doxorubicin treatment completely eliminated EDRP but not LDRP. Furthermore, baseline AML samples (n = 44) showed significantly higher GCN5 at mRNA and protein levels in MRD positive compared to MRD negative samples. Additionally, meta-analysis (n = 221) showed high GCN5 expression correlates with poor overall survival. Together, these results provide important insights into the molecular mechanism specific to EDRP and will have implications for the development of novel therapeutics for AML.

Discovery of 1,2,3-Triazole Derivatives for Multimodality PET/CT/Cryoimaging of Myelination in the Central Nervous System.

Myelin pathology is present in many neurological conditions such as multiple sclerosis (MS) and traumatic spinal cord injury (SCI). To facilitate development of novel therapies aimed at myelin repair, we set out to develop imaging agents that permit direct quantification of myelination in vivo. In this work, we designed and synthesized a series of fluorescent fluorinated myelin imaging agents that can be used for in vivo positron emission tomography (PET) imaging combined with subsequent post-mortem fluorescent cryoimaging. Structure-activity relationship (SAR) studies of the newly developed myelin imaging agents led us to identify a lead compound (TAFDAS, 21) that readily enters the brain and spinal cord and selectively binds to myelin. By conducting sequential PET and 3D cryoimaging in an SCI rat model, we demonstrated for the first time that PET and cryoimaging can be combined as a novel technique to image the spinal cord with high sensitivity and spatial resolution.

Design, Synthesis, and Evaluation of Fluorinated Radioligands for Myelin Imaging.

Myelination is one of the fundamental processes in vertebrates. A major challenge is to quantitatively image myelin distribution in the central nervous system. For this reason, we designed and synthesized a series of fluorinated radioligands that can be radiolabeled as radiotracers for positron emission tomography (PET) imaging of myelin. These newly developed radioligands readily penetrate the blood-brain barrier and selectively bind to myelin membranes in the white matter region. Structure-activity relationship studies of such ligands suggested that optimal permeability could be achieved with calculated lipophilicty in the range of 3-4. After radiolabeling with fluorine-18, the brain uptake and retention of each radioligand were determined by microPET/CT imaging studies. These pharmacokinetic studies led us to identify a lead compound ([(18)F]FMeDAS, 32) with promising in vivo binding properties, which was subsequently validated by ex vivo autoradiography.