Metallization and biopatterning on ultra-flexible substrates via dextran sacrificial layers

FLECS technology for high-throughput screening of hypercontractile cellular phenotypes in fibrosis: A function-first approach to anti-fibrotic drug discovery

The pivotal role of myofibroblast contractility in the pathophysiology of fibrosis is widely recognized, yet HTS approaches are not available to quantify this critically important function in drug discovery. We developed, validated, and scaled-up a HTS platform that quantifies contractile function of primary human lung myofibroblasts upon treatment with pro-fibrotic TGF-β1. With the fully automated assay we screened a library of 40,000 novel small molecules in under 80 h of total assay run-time. We identified 42 hit compounds that inhibited the TGF-β1-induced contractile phenotype of myofibroblasts, and enriched for 19 that specifically target myofibroblasts but not phenotypically related smooth muscle cells. Selected hits were validated in an ex vivo lung tissue models for their inhibitory effects on fibrotic gene upregulation by TGF-β1. Our results demonstrate that integrating a functional contraction test into the drug screening process is key to identify compounds with targeted and diverse activity as potential anti-fibrotic agents.

Engineered nasal dry powder for the encapsulation of bioactive compounds

In this review, we present the potential of nasal dry powders to deliver stable bioactive compounds and their manufacture using spray-drying (SD) techniques to achieve encapsulation. We also review currently approved and experimental excipients used for powder manufacturing for specific target drugs. Polymers, sugars, and amino acids are recommended for specific actions, such as mucoadhesive interactions, to increase residence time on the nasal mucosa; for example, high-molecular weight polymers, such as hydroxypropyl methylcellulose, or mannitol, which protect the bioactive compounds, increase their stability, and enhance drug absorption in the nasal mucosa; and leucine, which promotes particle formation and improves aerosol performance. Teaser: XXXX.

Multi-Functional Hydrogel-Interlayer RF/NFC Resonators as a Versatile Platform for Passive and Wireless Biosensing

Wearable sensors promise to transform human understanding of body state. However, despite many wearable sensor modalities that exist, few demonstrate the raw capabilities required for many emerging healthcare applications-passivity (and microelectronics-free), wireless readout, long-term operation, and specificity. Hydrogel-interlayer radio-frequency resonators are demonstrated as a versatile platform for passive and wireless biosensing. Fabricated using a simple vinyl cutter, the base resonator is composed of unanchored, broad-side coupled coils interceded by multifunctional hydrogels-such resonators are tuned to be sensitive to specific analytical or physical signals by modifying hydrogel composition. These resonators are transformed into near-field communication (NFC) sensor circuits through the simple attachment of an LED. These enable direct quantification of sensor state by cellphone and eye with no specialized electronics required. Resonator arrays are finally fused with silicone to form soft, wireless sensor skins that enable co-readout of analytical to physical signals while molded to human subjects. Such low-cost, accessible platforms can integrate with environments in transformative ways, enabling new applications in wireless sensing.

Passive and wireless, implantable glucose sensing with phenylboronic acid hydrogel-interlayer RF resonators

A phenylboronic acid-based, hydrogel-interlayer Radio-Frequency (RF) resonator is demonstrated as a highly-responsive, passive and wireless sensor for glucose monitoring. Constructs are composed of unanchored, capacitively-coupled split rings interceded by glucose-responsive hydrogels. Phenylboronic acid-hydrogels exhibit volumetric and dielectric variations in response to environmental glucose concentrations-these are efficiently converted to large shifts in the resonant response of interlayer-RF sensors. These tiny, stretchable and scalable sensors (5 mm × 5 mm x 250 μm) require no microelectronics or power at the sensing node and can be read-out remotely via near-field coupling. Sensors exhibit high sensitivities (~10% shift in resonant frequency-corresponding to 50 MHz-per 150 mg/dL of glucose), possess a limit of detection of 10 mg/dL, and a step response time of approximately 1 h to abrupt shifts in carbohydrate concentration. Notably, these sensors exhibited no signal drift or hysteresis over the time periods characterized herein (45 days at room temperature). We transform sensors into bioelectronic RF reporter-tags via the attachment of a single LED-these remotely report on glucose concentration via emitted light. We anticipate the non-degradative, long-term nature of both RF read-out and phenylboronic acid-based hydrogels will enable biosensors capable of long-term, remote read-out of glucose.

Efficacy of dextran and peptide-everolimus bi-directional stent

Everolimus inhibits stent restenosis and the WKYMV (fluorescein isothiocyanate) peptide promotes endothelial homing. Dextran is a natural polymer that is widely used as a pharmaceutical agent. The purpose of this study was to develop a double-drug-coated stent using a bidirectional coating system and to examine the surface shape with in vitro experiments. Stent length was 16 mm and strut thickness was 70 µm (Chonnam National University Hospital Tiger stent). Optical and scanning electron microscopy showed good coating without cracks or bubbles. Fluorescein isothiocyanate-peptide was dip-coated on the lumen and the abluminal surface was coated with everolimus and dextran. Stents were coated with dextran, everolimus, or everolimus-dextran. The radial force and flexibility were measured to determine the mechanical properties. Contact angle testing was performed in all groups. Dextran and peptide as hydrophilic substances and everolimus as a hydrophobic substance were each coated on cover glasses (cobalt-chromium). A10 and human umbilical vein endothelial cells were used in the experiments. Water and dimethyl sulfoxide served as a control, and three drug groups were tested: peptide-everolimus, everolimus-dextran, and peptide-everolimus-dextran. Immunocytochemistry was performed to assess cell adhesion. Light intensity was plotted according to the average on nuclear staining. Experiments were conducted using 5-bromo-2'-deoxyuridine to investigate A10 and human umbilical vein endothelial cell proliferation. Cell adhesion and proliferation of peptide-everolimus-dextran were inhibited at A10, and human umbilical vein endothelial cell was found to proliferate with cell adhesion. On conclusion, dextran and peptide-everolimus bidirectional stent is effective in re-endothelialization and inhibition of cell proliferation.

Obesity increases airway smooth muscle responses to contractile agonists

The asthma-obesity syndrome represents a major public health concern that disproportionately contributes to asthma severity and induces insensitivity to therapy. To date, no study has shown an intrinsic difference between human airway smooth muscle (HASM) cells derived from nonobese subjects and those derived from obese subjects. The objective of this study was to address whether there is a greater response to agonist-induced calcium mobilization, phosphorylation of myosin light chain (MLC), and greater shortening in HASM cells derived from obese subjects. HASM cells derived from nonobese and obese subjects were age and sex matched. Phosphorylation of MLC was measured after having been stimulated by carbachol. Carbachol- or histamine-induced mobilization of calcium and cell shortening were assessed in HASM cells derived from nonobese and obese donors. Agonist-induced MLC phosphorylation, mobilization of calcium, and cell shortening were greater in obese compared with non-obese-derived HASM cells. The MLC response was comparable in HASM cells derived from obese nonasthma and nonobese fatal asthma subjects. HASM cells derived from obese female subjects were more responsive to carbachol than HASM cells derived from obese male subjects. Insulin pretreatment had little effect on these responses. Our results show an increase in agonist-induced calcium mobilization associated with an increase in MLC phosphorylation and an increase in ASM cell shortening in favor of agonist-induced hyperresponsiveness in HASM cells derived from obese subjects. Our studies suggest that obesity induces a retained phenotype of hyperresponsiveness in cultured human airway smooth muscle cells.

Functional, RF-Trilayer Sensors for Tooth-Mounted, Wireless Monitoring of the Oral Cavity and Food Consumption

Wearable devices have emerged as powerful tools for personalized healthcare in spite of some challenges that limit their widespread applicability as continuous monitors of physiological information. Here, a materials-based strategy to add utility to traditional dielectric sensors by developing a conformal radiofrequency (RF) construct composed of an active layer encapsulated between two reverse-facing split ring resonators is applied. These small (down to 2 mm × 2 mm) passive dielectric sensors possess enhanced sensitivity and can be further augmented by functionalization of this interlayer material. Demonstrator devices are shown where the interlayer is: (i) a porous silk film, and (ii) a modified PNIPAM hydrogel that swells with pH or temperature. In vivo use is demonstrated by adhesion of the device on tooth enamel to detect foods during human ingestion. Such sensors can be easily multiplexed and yield data-rich temporal information during the diffusion of analytes within the trilayer structure. This format could be extended to a suite of interlayer materials for sensing devices of added use and specificity.

Elastomeric sensor surfaces for high-throughput single-cell force cytometry

As cells with aberrant force-generating phenotypes can directly lead to disease, cellular force-generation mechanisms are high-value targets for new therapies. Here, we show that single-cell force sensors embedded in elastomers enable single-cell force measurements with ~100-fold improvement in throughput than was previously possible. The microtechnology is scalable and seamlessly integrates with the multi-well plate format, enabling highly parallelized time-course studies. In this regard, we show that airway smooth muscle cells isolated from fatally asthmatic patients have innately greater and faster force-generation capacity in response to stimulation than healthy control cells. By simultaneously tracing agonist-induced calcium flux and contractility in the same cell, we show that the calcium level is ultimately a poor quantitative predictor of cellular force generation. Finally, by quantifying phagocytic forces in thousands of individual human macrophages, we show that force initiation is a digital response (rather than a proportional one) to the proper immunogen. By combining mechanobiology at the single-cell level with high-throughput capabilities, this microtechnology can support drug-discovery efforts for clinical conditions associated with aberrant cellular force generation.

FLECS Technology for High-Throughput Single-Cell Force Biology and Screening

Dr. Ivan Pushkarsky from the Department of Bioengineering at UCLA and Forcyte Biotechnologies, Inc. was awarded The President's Innovation Award at the Annual Society of Biomolecular Imaging and Informatics meeting held in San Diego, September 2017. All cell types produce mechanical forces to serve important physiological roles. Since aberrant force-generating phenotypes directly lead to disease, cellular force-generation mechanisms are high-value targets for new therapies. Despite knowledge of their significance in disease, drug developers have had limited access to force-generating cellular phenotypes, especially in the context of high-throughput screening. To serve this valuable need, we have developed a platform microtechnology called "FLECS" that can acquire robust contractility data from 1000s of uniformly patterned single cells simultaneously and seamlessly integrates with the 96- and 384-well plate formats to facilitate large-scale drug screens. This perspective discusses the challenges facing existing laboratory methods for measuring cellular force in the context of drug discovery. It then provides an overview of the FLECS platform, describes how it was designed to overcome many of these challenges, and discusses some exciting work already accomplished with FLECS. It concludes by highlighting the platform nature of the technology and the potential value that it promises for a myriad of drug development efforts.

Patterning of supported gold monolayers via chemical lift-off lithography

The supported monolayer of Au that accompanies alkanethiolate molecules removed by polymer stamps during chemical lift-off lithography is a scarcely studied hybrid material. We show that these Au-alkanethiolate layers on poly(dimethylsiloxane) (PDMS) are transparent, functional, hybrid interfaces that can be patterned over nanometer, micrometer, and millimeter length scales. Unlike other ultrathin Au films and nanoparticles, lifted-off Au-alkanethiolate thin films lack a measurable optical signature. We therefore devised fabrication, characterization, and simulation strategies by which to interrogate the nanoscale structure, chemical functionality, stoichiometry, and spectral signature of the supported Au-thiolate layers. The patterning of these layers laterally encodes their functionality, as demonstrated by a fluorescence-based approach that relies on dye-labeled complementary DNA hybridization. Supported thin Au films can be patterned via features on PDMS stamps (controlled contact), using patterned Au substrates prior to lift-off (e.g., selective wet etching), or by patterning alkanethiols on Au substrates to be reactive in selected regions but not others (controlled reactivity). In all cases, the regions containing Au-alkanethiolate layers have a sub-nanometer apparent height, which was found to be consistent with molecular dynamics simulations that predicted the removal of no more than 1.5 Au atoms per thiol, thus presenting a monolayer-like structure.

Gα12 facilitates shortening in human airway smooth muscle by modulating phosphoinositide 3-kinase-mediated activation in a RhoA-dependent manner

BACKGROUND AND PURPOSE

PI3K-dependent activation of Rho kinase (ROCK) is necessary for agonist-induced human airway smooth muscle cell (HASMC) contraction, and inhibition of PI3K promotes bronchodilation of human small airways. The mechanisms driving agonist-mediated PI3K/ROCK axis activation, however, remain unclear. Given that G12 family proteins activate ROCK pathways in other cell types, their role in M3 muscarinic acetylcholine receptor-stimulated PI3K/ROCK activation and contraction was examined.

EXPERIMENTAL APPROACH

Gα12 coupling was evaluated using co-immunoprecipitation and serum response element (SRE)-luciferase reporter assays. siRNA and pharmacological approaches, as well as overexpression of a regulator of G-protein signaling (RGS) proteins were applied in HASMCs. Phosphorylation levels of Akt, myosin phosphatase targeting subunit-1 (MYPT1), and myosin light chain-20 (MLC) were measured. Contraction and shortening were evaluated using magnetic twisting cytometry (MTC) and micro-pattern deformation, respectively. Human precision-cut lung slices (hPCLS) were utilized to evaluate bronchoconstriction.

KEY RESULTS

Knockdown of M3 receptors or Gα12 attenuated activation of Akt, MYPT1, and MLC phosphorylation. Gα12 coimmunoprecipitated with M3 receptors, and p115RhoGEF-RGS overexpression inhibited carbachol-mediated induction of SRE-luciferase reporter. p115RhoGEF-RGS overexpression inhibited carbachol-induced activation of Akt, HASMC contraction, and shortening. Moreover, inhibition of RhoA blunted activation of PI3K. Lastly, RhoA inhibitors induced dilation of hPCLS.

CONCLUSIONS AND IMPLICATIONS

Gα12 plays a crucial role in HASMC contraction via RhoA-dependent activation of the PI3K/ROCK axis. Inhibition of RhoA activation induces bronchodilation in hPCLS, and targeting Gα12 signaling may elucidate novel therapeutic targets in asthma. These findings provide alternative approaches to the clinical management of airway obstruction in asthma.

Association of PECAM-1 Gene Polymorphisms with Kawasaki Disease in Chinese Children

Kawasaki disease (KD) is an acute systemic vasculitis complicated by development of coronary artery lesions. PECAM-1 is a kind of cell adhesion molecule, which plays an important role in coronary artery disease. The relationship between PECAM-1 gene polymorphisms and their susceptibility to Kawasaki diseases (KD) is still unclear. In our study, we examined the PECAM-1 gene polymorphisms in 44 KD patients and 59 healthy children and revealed the correlation of PECAM-1 gene polymorphisms in KD children with and without coronary artery lesions (CAL).

New insights and perspectives into biological materials for flexible electronics

Materials based on biological materials are becoming increasingly competitive and are likely to be critical components in flexible electronic devices.

Nanocontact Printing of Proteins on Physiologically Soft Substrates to Study Cell Haptotaxis

Surface bound guidance cues and gradients are vital for directing cellular processes during development and repair. In vivo, these cues are often presented within a soft extracellular matrix with elastic moduli E < 10 kPa, but in vitro haptotaxis experiments have been conducted primarily on hard substrates with elastic moduli in the MPa to GPa range. Here, a technique is presented for patterning haptotactic proteins with nanometer resolution on soft substrates with physiological elasticity. A new nanocontact printing process was developed that circumvented the use of plasma activation that was found to alter the mechanical properties of the substrate. A dissolvable poly(vinyl alcohol) film was first patterned by lift-off nanocontact printing, and in turn printed onto the soft substrate, followed by dissolution of the film in water. An array of 100 unique digital nanodot gradients (DNGs), consisting of millions of 200 × 200 nm² protein nanodots, was patterned in less than 5 min with with <5% average deviation from the original gradient design. DNGs of netrin-1, a known protein guidance cue, were patterned, and the unpatterned surface was backfilled with a reference surface consisting of 75% polyethylene glycol grafted with polylysine and 25% poly-d-lysine. Haptotaxis of C2C12 myoblasts demonstrated the functionality of the DNGs patterned on soft substrates. In addition, high densities of netrin-1 were observed to induce cell spreading, while live imaging of sinusoidal control gradients highlighted cell migration and navigation by "inching". The nanopatterning technique developed here paves the way for studying haptotactic responses to diverse digital nanodot patterns on surfaces covering the full range of physiological elasticity, and is expected to be applicable to the study of both culture and primary cells, such as neutrophils and neurons.

Inhibition of PI3K promotes dilation of human small airways in a rho kinase-dependent manner

Background and Purpose

Asthma manifests as a heterogeneous syndrome characterized by airway obstruction, inflammation and hyperresponsiveness (AHR). Although the molecular mechanisms remain unclear, activation of specific PI3K isoforms mediate inflammation and AHR. We aimed to determine whether inhibition of PI3Kδ evokes dilation of airways and to elucidate potential mechanisms.

Experimental Approach

Human precision cut lung slices from non‐asthma donors and primary human airway smooth muscle (HASM) cells from both non‐asthma and asthma donors were utilized. Phosphorylation of Akt, myosin phosphatase target subunit 1 (MYPT1) and myosin light chain (MLC) were assessed in HASM cells following either PI3K inhibitor or siRNA treatment. HASM relaxation was assessed by micro‐pattern deformation. Reversal of constriction of airways was assessed following stimulation with PI3K or ROCK inhibitors.

Key Results

Soluble inhibitors or PI3Kδ knockdown reversed carbachol‐induced constriction of human airways, relaxed agonist‐contracted HASM and inhibited pAkt, pMYPT1 and pMLC in HASM. Similarly, inhibition of Rho kinase also dilated human PCLS airways and suppressed pMYPT1 and pMLC. Baseline pMYPT1 was significantly elevated in HASM cells derived from asthma donors in comparison with non‐asthma donors. After desensitization of the β₂‐adrenoceptors, a PI3Kδ inhibitor remained an effective dilator. In the presence of IL‐13, dilation by a β agonist, but not PI3K inhibitor, was attenuated.

Conclusion and Implications

PI3Kδ inhibitors act as dilators of human small airways. Taken together, these findings provide alternative approaches to the clinical management of airway obstruction in asthma.

Rapid Software-Based Design and Optical Transient Liquid Molding of Microparticles

Microparticles with complex 3D shape and composition are produced using a novel fabrication method, optical transient liquid molding, in which a 2D light pattern exposes a photopolymer precursor stream shaped along the flow axis by software-aided inertial flow engineering.

Flexible and Stretchable Gold Microstructures on Extra Soft Poly(dimethylsiloxane) Substrates

Stretchable gold microstructures are reliably transferred onto an extra-soft elastomeric substrate. Several major challenges, including failure-free transfer and reliable bonding with the substrate, are addressed. The simple and reproducible fabrication allows extensive study and optimization of the stretchability of meanders in terms of thickness, geometry, and substrate. The results provide new insights for designing stretchable electronics and novel routes for stretchrelated, mechanobiological cell-interface applications.

Flexible and stretchable micromagnet arrays for tunable biointerfacing

A process to surface pattern polydimethylsiloxane (PDMS) with ferromagnetic structures of varying sizes (micrometer to millimeter) and thicknesses (>70 μm) is developed. Their flexibility and magnetic reach are utilized to confer dynamic, additive properties to a variety of substrates, such as coverslips and Eppendorf tubes. It is found that these substrates can generate additional modes of magnetic droplet manipulation, and can tunably steer magnetic-cell organization.