Delivery Of Reagents Research Articles

On the Mechanisms of Uptake of Tumor-Seeking Cyanine Dyes.

Molecular entities that localize in tumor tissue are clinically important for targeted delivery of diagnostic, imaging, and therapeutic reagents. Often these targeting entities are designed for specific receptors (e.g., EGFR or integrin receptors). However, there is a subset of cyanine-7 dyes that apparently localize in every type of solid tumor tissue (at least, no exceptions have been reported so far), and they persist there for several days. Consequently, these dyes can be used for near-IR optical imaging of tumors in animal studies, they can be conjugated with cytotoxic species to give experimental theranostics, and there is potential for expanding their use into the development of clinically useful derivatives. Data presented in the literature and in this work indicate that the half-lives of these compounds in serum at 37 °C is on the order of minutes to a few hours, so what accounts for the persistent fluorescence of these dyes in tumor tissue over periods of several days? Literature, solely based on tissue culture experiments featuring a particular receptor blocker, indicates that uptake of these dyes is mediated by the organic anion transporter proteins (OATPs). Data presented in this paper agrees with that conclusion for short-term uptake, but significantly expands understanding of the likely reasons for long-term uptake and persistent tumor localization in vivo.

Generation of CRISPR-Edited Rodents Using a Piezo-Driven Zygote Injection Technique.

Direct modification of the genome of the zygotes (i.e., one-cell embryos) by the CRISPR/Cas9-editing reagents, followed by embryo transfer to pseudopregnant females for live birth, has been the most effective method to generate laboratory rodent models for research. The method relies on proper delivery of the editing reagents into zygotes, which is commonly achieved by a standard or slightly modified pronuclear microinjection technique. In this chapter, we describe in detail an alternative delivery method, named piezo-driven cytoplasmic microinjection, which offers a superior embryo survival and birth rate. Because this method uses a much wider injection needle than that in pronuclear injection, it allows a larger volume of the editing materials to be transported into the zygotes, leading to an increase in the targeting efficiency. This also eliminates the clogging issues seen regularly in pronuclear injection. Moreover, Cytochalasin B that is used to soften zygotes during piezo-driven microinjection has been suggested a role in improving the knockin efficiency, which provides an additional benefit to use this injection method.

Preservation of exosomes at room temperature using lyophilization

The application of exosomes as a therapeutic reagent or drug delivery vehicle can be expanded by developing a method to preserve exosomes. Although exosomes are generally stored at −80 °C, this temperature is not suitable for their handling or transportation and, therefore, other storage methods are desirable. Lyophilization is a promising storage method that can be used to preserve various substances at room temperature. In this study, we sought to develop a room temperature preservation method for exosomes using lyophilization and compared the properties of the lyophilized exosomes with ones stored at −80 °C. Lyophilization without cryoprotectant resulted in the aggregation of B16BL6 melanoma-derived exosomes, while the addition of trehalose, a cryoprotectant, prevented aggregation during lyophilization. PAGE analysis revealed that the proteins and RNA of exosomes were protected following lyophilization in the presence of trehalose. Lyophilization had little effect on the pharmacokinetics of Gaussia luciferase (gLuc)-labeled exosomes after an intravenous injection into mice. Moreover, it was found that lyophilized exosomes retained the activity of loaded gLuc and immunostimulatory CpG DNA for approximately 4 weeks even when stored at 25 °C. In conclusion, lyophilization with trehalose is an effective method for the storage of exosomes for various applications.

Protein Transduction Domain Mimic (PTDM) Self-Assembly?

Intracellular protein delivery is an invaluable tool for biomedical research, as it enables fundamental studies of cellular processes and creates opportunities for novel therapeutic development. Protein delivery reagents such as cell penetration peptides (CPPs) and protein transduction domains (PTDs) are frequently used to facilitate protein delivery. Herein, synthetic polymer mimics of PTDs, called PTDMs, were studied for their ability to self-assemble in aqueous media as it was not known whether self-assembly plays a role in the protein binding and delivery process. The results obtained from interfacial tensiometry (IFT), transmission electron microscopy (TEM), transmittance assays (%T), and dynamic light scattering (DLS) indicated that PTDMs do not readily aggregate or self-assemble at application-relevant time scales and concentrations. However, additional DLS experiments were used to confirm that the presence of protein is required to induce the formation of PTDM-protein complexes and that PTDMs likely bind as single chains.

High-throughput deposition of chemical reagents via pen-plotting technique for microfluidic paper-based analytical devices

The deposition of chemical reagent inks on paper is a crucial step in the development and fabrication of microfluidic paper-based analytical devices (μPADs). A pen-plotting approach, delivering chemical ink deposition using technical pens filled with reagents and inserted into a desktop electronic plotter, is shown herein to be a versatile, low-cost, simple, rapid, reproducible, and high-throughput solution. The volume of the deposited ink was quantified gravimetrically, confirming that nanoliter volumes of reagents can be deposited reproducibly (e.g. 7.55 ± 0.37 nL/mm for a plotting speed of 10 cm/s) in detection zones of μPADs, typically spatially defined using wax printing. This approach was further investigated with regard to deposition of reagents in different geometrical forms (circular and linear), so demonstrating its applicability for preparation of μPADs with flexible design and application. By adjusting the plotting speed for linear deposition, lines with a relatively large range of widths (≈628–1192 μm) were created. Circular deposition was also demonstrated via delivery of reagents within wax printed circular fluidic barriers of a range of diameters (inner diameter = 1.5–7 mm). These capabilities were practically demonstrated via the fabrication of μPADs, based upon differing detection principles for determination of aluminum in natural waters using Morin as the fluorescent reagent. Traditional μPADs based on digital image colorimetry (DIC) were produced using circular deposition, whilst distance-based μPADs exploited linear deposition. Both types of μPADs developed using this method showed excellent precision for determination of trace concentrations of aluminium (average RSDs = 3.38% and 6.45%, and LODs = 0.5 ng (0.25 ppm) and 2 ng (0.5 ppm), for traditional and distance-based detection, respectively).

Pentafluoropropionic Anhydride Functionalized PAMAM Dendrimer as miRNA Delivery Reagent

Poly(amidoamine) (PAMAM) dendrimers are good candidates for nucleic acid delivery with their well-defined characteristics. MicroRNA (miRNA) mediated regulation of biological process are also active area of investigation. Fibroblast cells, such as MRC-5, are one of the cell lines used in biological researches due to their hard to transfect nature. In this two-staged study, cystamine core G5 PAMAM dendrimers were synthesized and modified with pentafluoropropionic anhydride (PA) and subsequently tested as miRNA delivery reagent on MRC-5 cells. Effect of fluorination against to naked G5 dendrimer over transfection efficiency was also investigated by molecular docking and quantitative structure-activity relationship (QSAR) calculations. Structural characterization of the synthesized dendrimers was verified by spectroscopic techniques. Gel retardation assay, particle size and transmission electron microscopy results demonstrated polyplex formation ability of fluorinated dendrimers with miRNA at nanoscale level. Zeta potential values indicated non-aggregation and increased stability of the polyplexes. Prepared polyplexes with fluorinated dendrimer showed over 90% cell viability and transfection efficiency. In silico calculations confirmed the stable complexation with miRNA and smooth penetration capability into the cell.

Reactivity of Ln(II) Complexes Supported by (C5H4Me)1– Ligands with THF and PhSiH3: Isolation of Ring-Opened, Bridging Alkoxyalkyl, Hydride, and Silyl Products

Reduction of CpMe3Ln(THF), 1-Ln (Ln = La and Gd; CpMe = C5H4Me), with KC8 in the presence of 2.2.2-cryptand (crypt) generates dark solutions, 2-Ln, with EPR spectra consistent with Ln(II) complexes: an eight-line hyperfine pattern for La at g = 1.971 and a broad single line for Gd at g = 1.988. The solutions decompose within minutes, and in the La system, a decomposition product was isolated in which a molecule of THF had been reduced by two electrons and ring-opened to generate an alkoxyalkyl-bridged bimetallic La(III) complex, [K(crypt)]2[(CpMe3La)2(μ-OCH2CH2CH2CH2)], 3-La. An analogous Pr complex, 3-Pr, was also crystallographically characterized. Since decomposition products were not readily isolated from the analogous yttrium CpMe3Y(THF)/KC8/crypt reaction, the composition of the solution of 2-Y was probed by addition of the hydrogen delivery reagent, PhSiH3, which had previously been reported to form U(III) hydrides from tris(cyclopentadienyl) U(II) complexes. This generated an Y(III) silyl complex,...

Hierarchical Porous Silicon and Porous Silicon Nanowires Produced with Regenerative Electroless Etching (ReEtching) and Metal Assisted Catalytic Etching (MACE)

ReEtching produces nanostructured silicon when a catalytic agent, e.g. dissolved V2O5, is used to facilitate etching between Si and H2O2. H2O2 regenerates dissolved V in a 5+ oxidation state, which initiates etching by injecting holes into the Si valence band. Independent control over the extent of reaction (controlled by the amount of H2O2 added) and the rate of reaction (controlled by the rate at which H2O2 is pumped into the etchant solution) allows us to porosify Si substrates of arbitrary size, shape and doping, including wafers, single-crystal powders, polycrystalline powders, metallurgical grade powder, Si nanowires, Si pillars and Si powders that have been textured with metal-assisted catalytic etching (MACE). Similarly, improved control over the nucleation and etching in MACE is achieved by pumped delivery of reagents. Nanowires are not produced directly by MACE of powders, rather they form when a porosified layers is cleaved by capillary forces or sonication.

3D Printed Microfluidic Probes

In this work, we fabricate microfluidic probes (MFPs) in a single step by stereolithographic 3D printing and benchmark their performance with standard MFPs fabricated via glass or silicon micromachining. Two research teams join forces to introduce two independent designs and fabrication protocols, using different equipment. Both strategies adopted are inexpensive and simple (they only require a stereolithography printer) and are highly customizable. Flow characterization is performed by reproducing previously published microfluidic dipolar and microfluidic quadrupolar reagent delivery profiles which are compared to the expected results from numerical simulations and scaling laws. Results show that, for most MFP applications, printer resolution artifacts have negligible impact on probe operation, reagent pattern formation, and cell staining results. Thus, any research group with a moderate resolution (≤100 µm) stereolithography printer will be able to fabricate the MFPs and use them for processing cells, or generating microfluidic concentration gradients. MFP fabrication involved glass and/or silicon micromachining, or polymer micromolding, in every previously published article on the topic. We therefore believe that 3D printed MFPs is poised to democratize this technology. We contribute to initiate this trend by making our CAD files available for the readers to test our “print & probe” approach using their own stereolithographic 3D printers.

Enhanced remedial reagents delivery in unsaturated anisotropic soils using surfactant foam

Homogeneous delivery of solution of oxidant in unsaturated soils is limited by soil anisotropy and gravity. An innovative injection strategy using foam was developed to improve in situ delivery. Primary foam injection before oxidant solution enhanced both the lateral and uniform delivery of reactant in isotropic and anisotropic (permeability, contamination) soils. The oxidant spread isotropically through the foam water network. This sequential injection heavily improved the delivery radius of influence (ROI), while limiting contact between surfactant and solution of oxidant in order to preserve the selective oxidation of petroleum hydrocarbons contaminant (TPH). Prior foam injection allowed uniform delivery of the solution of oxidant across the region occupied by the foam, regardless of the soil permeability contrast (1:18), whereas poor ROI were observed for the direct injection of oxidant. Experiments in contamination contrasted soils showed that foam was able to propagate in highly TPH contaminated soils (max 60% velocity reduction for 22 g.kgdry soil−1). As for permeability contrast, foam is expected to enhance reagents delivery in such contexts. This novel strategy was proven to be efficient, even for complex anisotropic conditions, and should allow to cut field costs and uncertainties associated to poor reagents delivery.

Unique SiO2 Nanourchins Enable Amplification in Living Cells for In Situ Imaging of mRNAs

AbstractSufficient delivery of nucleic acid reagents into cells for amplifications with great activities would be significant for in situ intracellular imaging of messenger RNAs in living cells, showing great potentials in chemistry and biology. Herein, SiO2 nanourchins (SNUs) are developed, with two‐pronged pair of primers anchored on enzyme‐functionalized mesoporous SiO2 cores, for in situ imaging of mRNAs in living cells. Endowed by the urchins‐like structure to represent high loading capacity, efficient activity without mutual interference, and sufficient delivery into cells, SNUs maintain sustainable reactivities for amplification through primers' 3′‐end complete exposure and synergistic reagents release by increased dissociation or mobility during hybridization. “One‐step” reverse‐transcription helicase‐dependent isothermal amplifications are employed in living cells with Klenow (exo−) DNA polymerase to accomplish reverse transcriptions and polymerization amplifications. With high efficiency and stability, low toxicity, and good specificity, this method can detect amol of mRNA in dozens of microliter samples (<0.02 molecules per cell) in living cells, providing an ultrasensitive tool for fundamental understanding of mRNAs in cellular processes.

Abstract 5111: Gene editing in the NSG mouse strain and its genetic derivatives

Abstract Mouse models continue to be powerful tools in preclinical oncology and immuno-oncology studies. The development of the inbred highly immunocompromised mouse strain NSG (NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ) has dramatically improved the ability to work with human tumors in an organismal context using xenograft approaches. Furthermore, technical innovations have expanded the utility of this personalized tumor platform via the reconstitution of parts of the human immune system. An example of this is the NSG-SGM3 inbred mouse strain, in which transgenes expressing human IL3, GMCSF and SCF have been stably integrated into the NSG background. This NSG “derivative” strain can effectively support the stable engraftment of human myeloid lineages and the regulatory T cell populations. Direct genetic modification of the NSG genome in mouse embryos was a key technical capability to attain this NSG “derivative” strain rapidly and avoid extensive breeding. Modification of NSG and derivative strains represent an opportunity to optimize the engraftment of other human lineages. The ability to apply modern genome modification technology to different inbred mouse strains is highly desirable but must overcome two major technical hurdles - 1) Reproductive biology constraints that prevent live born progeny after reagent delivery methods such as microinjection or electroporation and 2) Cell intrinsic DNA-repair processes that are a prerequisite enabling gene editing tools. Given the SCID mutation (Prkdcscid) in the NSG background compromises some DNA repair pathways, it was not clear whether nuclease assisted recombination technologies would be a robust tool to modify NSG (and derivatives) genomes at the zygote stage. Here, we demonstrate that CRISPR-Cas9 is an effective tool for introducing genome modifications in NSG and present a specific example using the Hprt locus. Furthermore, we will present general experience with genomic modifications using NSG, and its derivatives, to emphasize direct modification of these genomes is technically feasible and is enabling the rapid sequential genetic tailoring in this high value cancer model strain. Citation Format: David S. Grass, F William Buaas, Michael V. Wiles, Benjamin E. Low, Peter Kutny. Gene editing in the NSG mouse strain and its genetic derivatives [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5111.

Colorimetric determination of alcohols in spirit drinks using a reversible solid sensor

A sensor for the colorimetric estimation of the alcoholic content has been developed based on the entrapment of the reagent (4-N,N-dioctylamino)-4‘-trifluoroacetylazobenzene (ETHT 4001) into polydimethylsiloxane (PDMS) modified with tretraethylorthosilicate (TEOS). When exposed to an alcoholic media, the sensor delivers ETHT 4001 so that it reacts with alcohols, resulting in a change in the solution color. The diffusion of the entrapped ETHT 4001 from the polymeric sensor to the working solution depends on the hydrophobicity of both the sensor matrix and the media, while the time of exposure determines whether the reagent reacts with methanol, or with methanol and ethanol. Thus, the sensors are a versatile tool for the estimation of the methanol content in ethanol or in ethanol/water mixtures, and for the measurement of the total alcoholic content (methanol plus ethanol) in an hydroalcoholic media. The proposed sensors are very easy to prepare, and show good precision and long-term stability. Moreover, the reagent delivery is reversible which allows its recovery once the absorbance measurements have been made simply by adding water, so the sensors can be reutilized and the generation of wastes is reduced. The potential utility of the proposed sensors has been demonstrated by measuring the alcoholic strength of commercial spirit drinks, and the methanol content in spiked hydroalcoholic samples.

Fibrin glue mediated delivery of bone anabolic reagents to enhance healing of tendon to bone.

Tendon graft healing in bone tunnels for the fixation of intra-articular ligament reconstructions may limit clinical outcome by delaying healing. This study assesses the effects of hydrogel-mediated delivery of bone anabolic growth factors in a validated model of tendon-to-bone tunnel healing. Forty-five Wistar rats were randomly allocated into three groups (BMP2-treated, GSK126-treated, and placebo). All animals underwent a tendon-to-bone tunnel reconstruction. Healing was evaluated at 4 weeks by biomechanical assessment, micro-computed tomography (bone mineral density, bone volume, cross sectional area of bone tunnels), and traditional histology. Adverse events associated with the hydrogel-mediated delivery of drugs were not observed. Results of our biomechanical assessment demonstrated favorable trends in animals treated with bone anabolic factors for energy absorption (P = 0.116) and elongation (P = 0.054), while results for force to failure (P = 0.691) and stiffness (P = 0.404) did not show discernible differences. Cross sectional areas for BMP2-treated animals were reduced, but neither BMP2 nor GSK126 administration altered bone mineral density (P = 0.492) or bone volume in the bone tunnel. These results suggest a novel and positive effect of bone anabolic factors on tendon-to-bone tunnel healing. Histological evaluation confirmed absence of collagen fibers crossing the soft tissue-bone interface indicating immature graft integration as expected at this time point. Our study indicates that hydrogel-mediated delivery of BMP2 and GSK126 appears to be safe and has the potential to enhance tendon-to-bone tunnel healing in ligament reconstructions.

Electrolytic CO2 Reduction in a Flow Cell.

Electrocatalytic CO2 conversion at near ambient temperatures and pressures offers a potential means of converting waste greenhouse gases into fuels or commodity chemicals (e.g., CO, formic acid, methanol, ethylene, alkanes, and alcohols). This process is particularly compelling when driven by excess renewable electricity because the consequent production of solar fuels would lead to a closing of the carbon cycle. However, such a technology is not currently commercially available. While CO2 electrolysis in H-cells is widely used for screening electrocatalysts, these experiments generally do not effectively report on how CO2 electrocatalysts behave in flow reactors that are more relevant to a scalable CO2 electrolyzer system. Flow reactors also offer more control over reagent delivery, which includes enabling the use of a gaseous CO2 feed to the cathode of the cell. This setup provides a platform for generating much higher current densities ( J) by reducing the mass transport issues inherent to the H-cells. In this Account, we examine some of the systems-level strategies that have been applied in an effort to tailor flow reactor components to improve electrocatalytic reduction. Flow reactors that have been utilized in CO2 electrolysis schemes can be categorized into two primary architectures: Membrane-based flow cells and microfluidic reactors. Each invoke different dynamic mechanisms for the delivery of gaseous CO2 to electrocatalytic sites, and both have been demonstrated to achieve high current densities ( J > 200 mA cm-2) for CO2 reduction. One strategy common to both reactor architectures for improving J is the delivery of CO2 to the cathode in the gas phase rather than dissolved in a liquid electrolyte. This physical facet also presents a number of challenges that go beyond the nature of the electrocatalyst, and we scrutinize how the judicious selection and modification of certain components in microfluidic and/or membrane-based reactors can have a profound effect on electrocatalytic performance. In membrane-based flow cells, for example, the choice of either a cation exchange membrane (CEM), anion exchange membrane (AEM), or a bipolar membrane (BPM) affects the kinetics of ion transport pathways and the range of applicable electrolyte conditions. In microfluidic cells, extensive studies have been performed upon the properties of porous carbon gas diffusion layers, materials that are equally relevant to membrane reactors. A theme that is pervasive throughout our analyses is the challenges associated with precise and controlled water management in gas phase CO2 electrolyzers, and we highlight studies that demonstrate the importance of maintaining adequate flow cell hydration to achieve sustained electrolysis.

Trans-Tympanic Drug Delivery for the Treatment of Ototoxicity.

The systemic administration of protective agents to treat drug-induced ototoxicity is limited by the possibility that these protective agents could interfere with the chemotherapeutic efficacy of the primary drugs. This is especially true for the drug cisplatin, whose anticancer actions are attenuated by antioxidants which provide adequate protection against hearing loss. Other current or potential otoprotective agents could pose a similar problem, if administered systemically. The application of various biologicals or protective agents directly to the cochlea would allow for high levels of these agents locally with limited systemic side effects. In this report, we demonstrate a trans-tympanic method of delivery of various drugs or biological reagents to the cochlea, which should enhance basic science research on the cochlea and provide a simple way of directing the use of otoprotective agents in the clinics. This report details a method of trans-tympanic drug delivery and provides examples of how this technique has been used successfully in experimental animals to treat cisplatin ototoxicity.

Optimized anion exchange column isolation of zirconium-89 (89Zr) from yttrium cyclotron target: Method development and implementation on an automated fluidic platform

Zirconium-89 (89Zr), produced by the (p, n) reaction from naturally monoisotopic yttrium (natY), is a promising positron emitting isotope for immunoPET imaging. Its long half-life of 78.4 h is sufficient for evaluating slow physiological processes. A prototype automated fluidic system, coupled to on-line and in-line detectors, has been constructed to facilitate development of new 89Zr purification methodologies. The highly reproducible reagent delivery platform and near-real time monitoring of column effluents allows for efficient method optimization. The separation of Zr from dissolved Y metal targets was evaluated using several anion exchange resins. Each resin was evaluated against its ability to quantitatively capture Zr from a load solution high in dissolved Y. The most appropriate anion exchange resin for this application was identified, and the separation method was optimized. The method is capable of a high Y decontamination factor (>105) and has been shown to remove Fe, an abundant contaminant in Y foils, from the 89Zr elution fraction. Finally, the method was evaluated using cyclotron bombarded Y foil targets; the method was shown to achieve >95% recovery of the 89Zr present in the foils. The anion exchange column method described here is intended to be the first 89Zr isolation stage in a dual-column purification process.

Spectroscopic methods for aqueous cyclodextrin inclusion complex binding measurement for 1,4-dioxane, chlorinated co-contaminants, and ozone

Recalcitrant organic contaminants, such as 1,4-dioxane, typically require advanced oxidation process (AOP) oxidants, such as ozone (O3), for their complete mineralization during water treatment. Unfortunately, the use of AOPs can be limited by these oxidants' relatively high reactivities and short half-lives. These drawbacks can be minimized by partial encapsulation of the oxidants within a cyclodextrin cavity to form inclusion complexes. We determined the inclusion complexes of O3 and three common co-contaminants (trichloroethene, 1,1,1-trichloroethane, and 1,4-dioxane) as guest compounds within hydroxypropyl-β-cyclodextrin. Both direct (ultraviolet or UV) and competitive (fluorescence changes with 6-p-toluidine-2-naphthalenesulfonic acid as the probe) methods were used, which gave comparable results for the inclusion constants of these species. Impacts of changing pH and NaCl concentrations were also assessed. Binding constants increased with pH and with ionic strength, which was attributed to variations in guest compound solubility. The results illustrate the versatility of cyclodextrins for inclusion complexation with various types of compounds, binding measurement methods are applicable to a wide range of applications, and have implications for both extraction of contaminants and delivery of reagents for treatment of contaminants in wastewater or contaminated groundwater.

Targeting Ability of c(RGDyK)-Functionalized Nanoparticles is Inhibited by Protein Coronas

Nanoparticles functionalized with targeting ligands have been proposed as effective carriers for the selective delivery of diagnostic or therapeutic reagents to desired locations in the body. However protein coronas formed on the surface of such functionalized nanoparticles may affect their targeting efficiency when introduced into physiological environment. Here, Zinc Doped Iron Oxide Nanoparticles (Zn0.4Fe2.6O4 NPs) were prepared, and functionalized with Cyclic arginine-glycine-aspartic Acid (c(RGDyK)) peptide to target U87MG cells.

Rapid Microvalve Actuated Electroosmotic Reagent Delivery to Surface-Immobilized Molecules

Significances of Bioengineering & Biosciences Rapid Microvalve Actuated Electroosmotic Reagent Delivery to Surface-Immobilized Molecules Hao Chen* University of Michigan, USA *Corresponding author: Hao Chen, University of Michigan, Biomedical Engineering, Ann Arbor, MI. 48109, USA Submission: November 17, 2017; Published: January 10, 2018 DOI: 10.31031/SBB.2018.01.000506 ISSN 2637-8078Volume1 Issue2