RNC received funding from South Carolina Bioengineering Center of Regeneration and Formation of Tissues Pilot grant supported by the National Institute of General Medical Sciences (NIGMS) of the National Institutes of Health, the American Association for the Study of Liver Diseases Foundation, and American Society of Gene &#38; Cell Therapy under grant numbers P30 GM131959, 2021000920, and 2022000099, respectively. The content is solely the responsibility of the authors and does not necessarily represent the official views of the American Society of Gene &#38; Cell Therapy or the American Association for the Study of Liver Diseases Foundation. The schematic for Figure 1 was created with BioRender.com.

<ol>
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(132), e56993 (2018).</li><li>Huang, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+functional+hepatocyte-like+cells+from+mouse+fibroblasts+by+defined+factors.">Induction of functional hepatocyte-like cells from mouse fibroblasts by defined factors.</a> Nature. 475 (7356), 386-389 (2011).</li><li>Severgnini, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+two-step+method+for+isolation+of+functional+primary+mouse+hepatocytes:+cell+characterization+and+asialoglycoprotein+receptor+based+assay+development.">A rapid two-step method for isolation of functional primary mouse hepatocytes: cell characterization and asialoglycoprotein receptor based assay development.</a> Cytotechnology. 64 (2), 187-195 (2012).</li><li>Jung, Y., Zhao, M., Svensson, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation,+culture,+and+functional+analysis+of+hepatocytes+from+mice+with+fatty+liver+disease.">Isolation, culture, and functional analysis of hepatocytes from mice with fatty liver disease.</a> STAR Protocols. 1 (3), 100222 (2020).</li><li>Kim, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+(3D)+printing+of+mouse+primary+hepatocytes+to+generate+3D+hepatic+structure.">Three-dimensional (3D) printing of mouse primary hepatocytes to generate 3D hepatic structure.</a> Annals of Surgical Treatment and Research. 92 (2), 67-72 (2017).</li><li>Li, W. C., Ralphs, K. L., Tosh, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+culture+of+adult+mouse+hepatocytes.">Isolation and culture of adult mouse hepatocytes.</a> Methods in Molecular Biology. 633, 185-196 (2010).</li><li>Lattanzi, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+CRISPR/Cas9+delivery+to+human+hematopoietic+stem+and+progenitor+cells+for+therapeutic+genomic+rearrangements.">Optimization of CRISPR/Cas9 delivery to human hematopoietic stem and progenitor cells for therapeutic genomic rearrangements.</a> Molecular Therapy. 27 (1), 137-150 (2019).</li><li>Dever, D. 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The authors have no competing interests to disclose.

The steps outlined in the protocol for hepatocyte isolation are challenging and require practice for proficiency. There are several key steps for the successful hepatocyte isolation from the liver. First, proper cannulation of the inferior vena cava is essential for complete liver perfusion. The absence of blanching in the liver after perfusion indicates displacement of the catheter (Table 1). The inferior vena cava (retrograde perfusion) was cannulated in the procedure because it is simpler and more acc...

IMDs of the liver are genetic disorders characterized by the deficiency of a crucial hepatic enzyme involved in metabolism that leads to the accumulation of toxic metabolites. Without treatment, IMDs of the liver result in organ failure or premature death1,2. The only curative option for patients with IMDs of the liver is orthotopic liver transplantation, which is limited due to the low availability of donor organs and complications from immunosuppressive therapy following the procedure3,4. According to recent data collected by the Organ Procurement and Transplantation Network, only 40%-46% of adult patients on the liver transplant waiting list receive an organ, while 12.3% of these patients die while on the waiting list5. Moreover, only 5% of all the rare liver diseases have an FDA-approved treatment6. It is clear that there is a critical need for novel treatments for IMDs of the liver. However, appropriate disease models are required to develop new therapeutic options.
Modeling human diseases using in vitro and in vivo systems remains an obstacle for developing effective therapies and studying the pathology of IMDs of the liver. Hepatocytes from patients with rare liver diseases are challenging to obtain7. Animal models are crucial for developing an understanding of disease pathology and for testing therapeutic strategies. However, one obstacle is generating models from embryos carrying lethal mutations. For example, attempts to create mouse models of Alagille Syndrome (ALGS) with embryos containing homozygous deletions of a 5 kb sequence near the 5&#8242;-end of the Jag1 gene resulted in the early death of the embryos8. In addition, generating mouse models by gene editing in embryonic stem cells can be time- and resource-intensive9. Lastly, mutations will appear outside the targeted tissue, leading to confounding variables that may impede study of the disease9. Somatic gene editing would allow for easier editing in liver tissue and bypasses the challenges associated with generating models using embryonic stem cells.
Electroporation enables the delivery of CRISPR-Cas9 directly into the nucleus by applying high-voltage currents to permeabilize the cell membrane and is compatible with many cell types, including those that are intransigent to transfection techniques, such as human embryonic stem cells, pluripotent stem cells, and neurons10,11,12. However, low viability is a potential drawback of electroporation; optimizing the procedure can yield high levels of delivery while limiting toxicity13. A recent study demonstrates the feasibility of electroporating CRISPR-Cas9 components into primary mouse and human hepatocytes as a highly efficient approach14. Ex vivo electroporation in hepatocytes has the potential to be applied to generate new mouse models for human IMDs of the liver.
This protocol provides a detailed step-by-step procedure for isolating mouse hepatocytes from the liver and subsequently electroporating CRISPR-Cas9 as RNP complexes, consisting of Cas9 protein and synthetic single-guide RNA (sgRNA), or Cas9 mRNA combined with sgRNA to obtain high levels of on-target gene editing. In addition, the protocol provides methods for quantifying gene editing efficiency, viability, and functionality following electroporation of CRISPR-Cas9 into freshly isolated mouse hepatocytes.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>0.2 mL PCR 8-tube FLEX-FREE strip, attached clear flat caps, natural</td>
			<td>USA Scientific</td>
			<td>1402-4700</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well Collagen Plates</td>
			<td>Advanced Biomatrix</td>
			<td>5073</td>
			<td></td>
		</tr>
		<tr>
			<td>accuSpin Micro 17R</td>
			<td>Fisher Scientific</td>
			<td>13-100-675</td>
			<td></td>
		</tr>
		<tr>
			<td>All-in-one Fluorescent Microscope</td>
			<td>Keyence</td>
			<td>BZ-X810</td>
			<td></td>
		</tr>
		<tr>
			<td>Analog Vortex Mixer</td>
			<td>VWR</td>
			<td>97043-562</td>
			<td></td>
		</tr>
		<tr>
			<td>ART Wide BORE filtered tips 1,000 &#181;L</td>
			<td>ThermoFisher Scientific</td>
			<td>2079GPK</td>
			<td></td>
		</tr>
		<tr>
			<td>Automated Cell Counter</td>
			<td>Bio-Rad Laboratories</td>
			<td>TC20</td>
			<td></td>
		</tr>
		<tr>
			<td>Blue Wax Dissection Tray</td>
			<td>Braintree Scientific Inc.</td>
			<td>DTW1</td>
			<td>9&#34; x 6.5&#34; x 1/2&#34;+F21</td>
		</tr>
		<tr>
			<td>Cell scraper/lifter</td>
			<td>Argos Technologies</td>
			<td>UX-04396-53</td>
			<td>Non-pyrogenic, sterile</td>
		</tr>
		<tr>
			<td>Conical tubes (15 mL)</td>
			<td>Fisher Scientific</td>
			<td>339650</td>
			<td></td>
		</tr>
		<tr>
			<td>Conical tubes (50 mL)</td>
			<td>Fisher Scientific</td>
			<td>14-432-22</td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton applicators</td>
			<td>Fisher Scientific</td>
			<td>22-363-170</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved scissors</td>
			<td>Cooper Surgical</td>
			<td>62131</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Petri Dishes</td>
			<td>Falcon</td>
			<td>351029</td>
			<td>100mm,sterile</td>
		</tr>
		<tr>
			<td>Disposable Petri Dishes</td>
			<td>VWR</td>
			<td>25373-100</td>
			<td>35mm, sterile</td>
		</tr>
		<tr>
			<td>Epoch Microplate Spectrophotometer</td>
			<td>BioTek Instruments</td>
			<td>250082</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon Cell strainer (70 &#181;m)</td>
			<td>Fisher Scientific</td>
			<td>08-771-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Cooper Surgical</td>
			<td>61864</td>
			<td>Euro-Med Adson Tissue Forceps</td>
		</tr>
		<tr>
			<td>IV catheters&#160;</td>
			<td>BD</td>
			<td>382612</td>
			<td>24 G x 0.75 in</td>
		</tr>
		<tr>
			<td>IV infusion set</td>
			<td>Baxter</td>
			<td>2C6401</td>
			<td></td>
		</tr>
		<tr>
			<td>MyFuge 12 Mini Centrifuge</td>
			<td>Benchmark Scientific</td>
			<td>1220P38</td>
			<td></td>
		</tr>
		<tr>
			<td>Needles</td>
			<td>Fisher Scientific</td>
			<td>05-561-20</td>
			<td>25 G</td>
		</tr>
		<tr>
			<td>Nucleofector 2b Device</td>
			<td>Lonza</td>
			<td>AAB-1001</td>
			<td>Program T-028 was used for electroporation in mouse hepatocytes</td>
		</tr>
		<tr>
			<td>Peristaltic Pump</td>
			<td>Masterflex</td>
			<td>&#160;HV-77120-42</td>
			<td>10 to 60 rpm; 90 to 260 VAC</td>
		</tr>
		<tr>
			<td>Precision pump tubing</td>
			<td>Masterflex</td>
			<td>HV-96410-14</td>
			<td>25 ft, silicone</td>
		</tr>
		<tr>
			<td>Primaria Culture Plates</td>
			<td>Corning Life Sciences</td>
			<td>353846</td>
			<td>Nitrogen-containing tissue culture plates</td>
		</tr>
		<tr>
			<td>Serological Pipets (25 mL)</td>
			<td>Fisher Scientific</td>
			<td>12-567-604</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringes</td>
			<td>BD</td>
			<td>329464</td>
			<td>1 mL, sterile</td>
		</tr>
		<tr>
			<td>T100 Thermal Cycler</td>
			<td>Bio-Rad Laboratories</td>
			<td>1861096</td>
			<td></td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>ALT</td>
			<td>27577</td>
			<td>Thermo Scientific Precision Microprocessor Controlled 280 Series, 2.5 L</td>
		</tr>
		<tr>
			<td>Reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Alt-R S.p. Cas9 Nuclease V3</td>
			<td>IDT</td>
			<td>1081058</td>
			<td></td>
		</tr>
		<tr>
			<td>Beckman Coulter AMPure XP, 5 mL</td>
			<td>Fisher Scientific</td>
			<td>NC9959336</td>
			<td></td>
		</tr>
		<tr>
			<td>CleanCap Cas9 mRNA</td>
			<td>Trilink Biotechnologies</td>
			<td>L-7606-100</td>
			<td></td>
		</tr>
		<tr>
			<td>CleanCap&#160;EGFP mRNA</td>
			<td>Trilink Biotechnologies</td>
			<td>L-7201-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning Matrigel Matrix</td>
			<td>Corning Life Sciences</td>
			<td>356234</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>ThermoFisher Scientific</td>
			<td>11885076</td>
			<td>Low glucose, pyruvate</td>
		</tr>
		<tr>
			<td>Ethanol 70%</td>
			<td>VWR</td>
			<td>71001-652</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Thermoscientific</td>
			<td>26140-079</td>
			<td></td>
		</tr>
		<tr>
			<td>Hepatocyte Maintenance Medium (MM)</td>
			<td>Lonza</td>
			<td>MM250</td>
			<td></td>
		</tr>
		<tr>
			<td>Hepatocyte Plating Medium (PM)</td>
			<td>Lonza</td>
			<td>MP100</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Albumin ELISA Kit</td>
			<td>Fisher Scientific</td>
			<td>NC0010653</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse/Rat Hepatocyte Nucleofector Kit</td>
			<td>Lonza</td>
			<td>VPL-1004</td>
			<td></td>
		</tr>
		<tr>
			<td>OneTaq HotStart DNA Polymerase</td>
			<td>New England Biolabs</td>
			<td>M0481L</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS 10x pH 7.4&#160;</td>
			<td>Thermoscientific</td>
			<td>70011-044</td>
			<td>No calcium or magnesium chloride</td>
		</tr>
		<tr>
			<td>Percoll (PVP solution)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-500790A</td>
			<td></td>
		</tr>
		<tr>
			<td>Periodic acid</td>
			<td>Sigma-Aldrich</td>
			<td>P7875-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>Permount Mounting Medium</td>
			<td>VWR</td>
			<td>100496-550</td>
			<td></td>
		</tr>
		<tr>
			<td>QuickExtract DNA Extraction Solution</td>
			<td>Lucigen Corporation</td>
			<td>QE05090</td>
			<td></td>
		</tr>
		<tr>
			<td>Schiff&#8217;s fuchsin-sulfite reagent</td>
			<td>Sigma-Aldrich</td>
			<td>S5133</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.25%)</td>
			<td>ThermoFisher Scientific</td>
			<td>25200056</td>
			<td>Phenol red</td>
		</tr>
		<tr>
			<td>Vybrant MTT Cell Viability Assay</td>
			<td>ThermoFisher Scientific</td>
			<td>V13154</td>
			<td></td>
		</tr>
		<tr>
			<td>Perfusion Solution 1 (pH 7.4, filter sterilized)&#160;</td>
			<td></td>
			<td></td>
			<td>Stable at 4 &#176;C for 2 months</td>
		</tr>
		<tr>
			<td>EBSS</td>
			<td>Fisher Scientific</td>
			<td>14155063</td>
			<td>Complete to 200 mL</td>
		</tr>
		<tr>
			<td>EGTA (0.5 M)</td>
			<td>Bioworld</td>
			<td>40520008-1</td>
			<td>200 &#181;L</td>
		</tr>
		<tr>
			<td>HEPES (pH 7.3, 1 M)</td>
			<td>ThermoFisher Scientific</td>
			<td>AAJ16924AE</td>
			<td>2 mL&#160;</td>
		</tr>
		<tr>
			<td>Perfusion Solution 2 (pH 7.4, filter sterilized)&#160;</td>
			<td></td>
			<td></td>
			<td>Stable at 4 &#176;C for 2 months</td>
		</tr>
		<tr>
			<td>CaCl2&#183;2H20 (1.8 mM)</td>
			<td>Sigma</td>
			<td>C7902-500G</td>
			<td>360 &#181;L of 1 M stock&#160;</td>
		</tr>
		<tr>
			<td>EBSS (no calcium, no magnesium, no phenol red)</td>
			<td>Fisher Scientific</td>
			<td>14-155-063</td>
			<td>Complete to 200 mL</td>
		</tr>
		<tr>
			<td>HEPES (1 M)</td>
			<td>ThermoFisher Scientific</td>
			<td>AAJ16924AE</td>
			<td>2 mL&#160;</td>
		</tr>
		<tr>
			<td>MgSO4&#183;7H20 (0.8 mM)</td>
			<td>Sigma</td>
			<td>30391-25G</td>
			<td>160 &#181;L of 1 M stock</td>
		</tr>
		<tr>
			<td>Perfusion Solution 3&#160;</td>
			<td></td>
			<td></td>
			<td>Prepared fresh prior to use</td>
		</tr>
		<tr>
			<td>Solution 2</td>
			<td></td>
			<td></td>
			<td>50 mL</td>
		</tr>
		<tr>
			<td>Liberase</td>
			<td>Roche</td>
			<td>5401127001</td>
			<td>0.094 Wunsch units/mL</td>
		</tr>
		<tr>
			<td>Mouse Anesthetic Cocktail&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Acepromzine</td>
			<td></td>
			<td></td>
			<td>0.25 mg/mL final concentration</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td></td>
			<td></td>
			<td>7.5 mg/mL final concentration</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td></td>
			<td></td>
			<td>1.5 mg/mL final concentration</td>
		</tr>
		<tr>
			<td>Software</td>
			<td>URL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Benchling</td>
			<td>https://www.benchling.com/</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ImageJ</td>
			<td>https://imagej.nih.gov/ij/</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>TIDE: Tracking of Indels by Decomposition</td>
			<td>https://tide.nki.nl/</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

electroporation-mediated delivery of cas9 ribonucleoproteins and mrna into freshly isolated primary mouse hepatocytes

This protocol describes a fast and effective method for isolating primary mouse hepatocytes followed by electroporation-mediated delivery of CRISPR-Cas9 as ribonucleoproteins (RNPs) and mRNA. Primary mouse hepatocytes were isolated using a three-step retrograde perfusion method resulting in high yields of up to 50 &#215; 106 cells per liver and cell viability of &#62;85%. This protocol provides detailed instructions for plating, staining, and culturing hepatocytes. The results indicate that electroporation provides a high transfection efficiency of 89%, as measured by the percentage of green fluorescent protein (GFP)-positive cells and modest cell viability of &#62;35% in mouse hepatocytes.
To demonstrate the utility of this approach, CRISPR-Cas9 targeting the hydroxyphenylpyruvate dioxygenase gene was electroporated into primary mouse hepatocytes as proof-of-principle gene editing to disrupt a therapeutic gene related to an inherited metabolic disease (IMD) of the liver. A higher on-target edit of 78% was observed for RNPs compared to 47% editing efficiency with mRNA. The functionality of hepatocytes was evaluated in vitro using an albumin assay that indicated that delivering CRISPR-Cas9 as RNPs and mRNA results in comparable cell viability in primary mouse hepatocytes. A promising application for this protocol is the generation of mouse models for human genetic diseases affecting the liver.

Isolation of plateable primary hepatocytes from the liver 
The overall process of liver perfusion and hepatocyte isolation is illustrated in Figure 1. In this experiment, wild-type, 8-10-week-old C57BL6/6J mice were used. The procedure is expected to yield 20-50 &#215; 106 cells per mouse with a viability between 85% and 95%. If the viability is &#60;70%, percoll treatment should be followed to remove dead cells. Freshly isolated hepatocytes should be plated ...

Watch this Scientific Journal Video about Electroporation-Mediated Delivery of Cas9 Ribonucleoproteins and mRNA into Freshly Isolated Primary Mouse Hepatocytes at JoVE.com

Electroporation-Mediated Delivery of Cas9 Ribonucleoproteins and mRNA into Freshly Isolated Primary Mouse Hepatocytes

This protocol describes techniques for isolating primary mouse hepatocytes from the liver and electroporating CRISPR-Cas9 as ribonucleoproteins and mRNA to disrupt a therapeutic target gene associated with an inherited metabolic disease of the liver. The methods described result in high viability and high levels of gene modification after electroporation.

This protocol describes a fast and effective method for isolating primary mouse hepatocytes followed by electroporation-mediated delivery of CRISPR-Cas9 ...

electroporation-mediated-delivery-cas9-ribonucleoproteins-mrna-into

Research

JoVE Journal

Bioengineering

2.5K Views.  Clemson University. This protocol describes techniques for isolating primary mouse hepatocytes from the liver and electroporating CRISPR-Cas9 as ribonucleoproteins and mRNA to disrupt a therapeutic target gene associated with an inherited metabolic disease of the liver. The methods described result in high viability and high levels of gene modification after electroporation. 

Video: Electroporation-Mediated Delivery of Cas9 Ribonucleoproteins and mRNA into Freshly Isolated Primary Mouse Hepatocytes

Self-reporting Scaffolds for 3-Dimensional Cell Culture

Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting 3D cellular construct can often be more relevant to studying the molecular events and cell-cell interactions than similar experiments studied in 2D. To create effective 3D cultures with high cell viability throughout the scaffold the culture conditions such as oxygen and pH need to be carefully controlled as gradients in analyte concentration can exist throughout the 3D construct. Here we describe the methods of preparing biocompatible pH responsive sol-gel nanosensors and their incorporation into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds along with their subsequent preparation for the culture of mammalian cells. The pH responsive scaffolds can be used as tools to determine microenvironmental pH within a 3D cellular construct. Furthermore, we detail the delivery of pH responsive nanosensors to the intracellular environment of mammalian cells whose growth was supported by electrospun PLGA scaffolds. The cytoplasmic location of the pH responsive nanosensors can be utilized to monitor intracellular pH (pHi) during ongoing experimentation.

Biocompatible pH responsive sol-gel nanosensors can be incorporated into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds. The produced self-reporting scaffolds can be used for in&#160;situ monitoring of microenvironmental conditions whilst culturing cells upon the scaffold. This is beneficial as the 3D cellular construct can be monitored in real-time without disturbing the experiment.

Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting ...

Porous Silicon Microparticles for Delivery of siRNA Therapeutics

Small interfering RNA (siRNA) can be used to suppress gene expression, thereby providing a new avenue for the treatment of various diseases. However, the successful implementation of siRNA therapy requires the use of delivery platforms that can overcome the major challenges of siRNA delivery, such as enzymatic degradation, low intracellular uptake and lysosomal entrapment. Here, a protocol for the preparation and use of a biocompatible and effective siRNA delivery system is presented. This platform consists of polyethylenimine (PEI) and arginine (Arg)-grafted porous silicon microparticles, which can be loaded with siRNA by performing a simple mixing step. The silicon particles are gradually degraded over time, thereby triggering the formation of Arg-PEI/siRNA nanoparticles. This delivery vehicle provides a means for protecting and internalizing siRNA, without causing cytotoxicity. The major steps of polycation functionalization, particle characterization, and siRNA loading are outlined in detail. In addition, the procedures for determining particle uptake, cytotoxicity, and transfection efficacy are also described.

Delivery remains the main challenge for the therapeutic implementation of small interfering RNA (siRNA). This protocol involves the use of a multifunctional and biocompatible siRNA delivery platform, consisting of arginine and polyethylenimine grafted porous silicon microparticles.

Small interfering RNA (siRNA) can be used to suppress gene expression, thereby providing a new avenue for the treatment of various diseases. However, the ...

Delivery of Proteins, Peptides or Cell-impermeable Small Molecules into Live Cells by Incubation with the Endosomolytic Reagent dfTAT

Macromolecular delivery strategies typically utilize the endocytic pathway as a route of cellular entry. However, endosomal entrapment severely limits the efficiency with which macromolecules penetrate the cytosolic space of cells. Recently, we have circumvented this problem by identifying the reagent dfTAT, a disulfide bond dimer of the peptide TAT labeled with the fluorophore tetramethylrhodamine. We have generated a fluorescently labeled dimer of the prototypical cell-penetrating peptide (CPP) TAT, dfTAT, which penetrates live cells and reaches the cytosolic space of cells with a particularly high efficiency. Cytosolic delivery of dfTAT is achieved in multiple cell lines, including primary cells. Moreover, delivery does not noticeably impact cell viability, proliferation or gene expression. dfTAT can deliver small molecules, peptides, antibodies, biologically active enzymes and a transcription factor. In this report, we describe the protocols involved in dfTAT synthesis and cellular delivery. The manuscript describes how to control the amount of protein delivered to the cytosolic space of cells by varying the amount of protein administered extracellularly. Finally, the current limitations of this new technology and steps involved in validating delivery are discussed. The described protocols should be extremely useful for cell-based assays as well as for the ex vivo manipulation and reprogramming of cells.

We describe how to deliver proteins and cell-impermeable small molecules into cultured mammalian cells by a simple co-incubation protocol with a reagent that causes endocytic organelles to become leaky.

Macromolecular delivery strategies typically utilize the endocytic pathway as a route of cellular entry. However, endosomal entrapment severely limits the ...

Microfluidic Flow Chambers Using Reconstituted Blood to Model Hemostasis and Platelet Transfusion In Vitro

Blood platelets prepared for transfusion gradually lose hemostatic function during storage. Platelet function can be investigated using a variety of (indirect) in vitro experiments, but none of these is as comprehensive as microfluidic flow chambers. In this protocol, the reconstitution of thrombocytopenic fresh blood with stored blood bank platelets is used to simulate platelet transfusion. Next, the reconstituted sample is perfused in microfluidic flow chambers which mimic hemostasis on exposed subendothelial matrix proteins. Effects of blood donation, transport, component separation, storage and pathogen inactivation can be measured in paired experimental designs. This allows reliable comparison of the impact every manipulation in blood component preparation has on hemostasis. Our results demonstrate the impact of temperature cycling, shear rates, platelet concentration and storage duration on platelet function. In conclusion, this protocol analyzes the function of blood bank platelets and this ultimately aids in optimization of the processing chain including phlebotomy, transport, component preparation, storage and transfusion.

Microfluidic Flow Chambers Using Reconstituted Blood to Model Hemostasis and Platelet Transfusion In Vitro

Platelet transfusion and hemostasis was modeled using blood reconstitution and microfluidic flow chambers to investigate the function of blood banking platelets. The data demonstrate the consequences of platelet storage lesion on hemostasis, in vitro.

Blood platelets prepared for transfusion gradually lose hemostatic function during storage. Platelet function can be investigated using a variety of ...

Manufacture and Drug Delivery Applications of Silk Nanoparticles

Silk is a promising biopolymer for biomedical and pharmaceutical applications due to its outstanding mechanical properties, biocompatibility and biodegradability, as well its ability to protect and subsequently release its payload in response to a trigger. While silk can be formulated into various material formats, silk nanoparticles are emerging as promising drug delivery systems. Therefore, this article covers the procedures for reverse engineering silk cocoons to yield a regenerated silk solution that can be used to generate stable silk nanoparticles. These nanoparticles are subsequently characterized, drug loaded and explored as a potential anticancer drug delivery system. Briefly, silk cocoons are reverse engineered first by degumming the cocoons, followed by silk dissolution and clean up, to yield an aqueous silk solution. Next, the regenerated silk solution is subjected to nanoprecipitation to yield silk nanoparticles &#8211; a simple but powerful method that generates uniform nanoparticles. The silk nanoparticles are characterized according to their size, zeta potential, morphology and stability in aqueous media, as well as their ability to entrap a chemotherapeutic payload and kill human breast cancer cells. Overall, the described methodology yields uniform silk nanoparticles that can be readily explored for a myriad of applications, including their use as a potential nanomedicine.

Nanoparticles are emerging as promising drug delivery systems for a broad range of indications. Here, we describe a simple yet powerful method to manufacture silk nanoparticles using reverse engineered Bombyx mori silk. These silk nanoparticles can be readily loaded with a therapeutic payload and subsequently explored for drug delivery applications.

Silk is a promising biopolymer for biomedical and pharmaceutical applications due to its outstanding mechanical properties, biocompatibility and ...

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is restricted to platelet deposition only. The intricate relationship between Ca2+-dependent coagulation and platelet function requires careful and controlled recalcification of blood prior to analysis. Our setup uses a Y-shaped mixing channel, which supplies concentrated Ca2+/Mg2+ buffer to flowing blood just prior to perfusion, enabling rapid recalcification without sample stasis. A ten-fold difference in flow velocity between both reservoirs minimizes dilution. The recalcified blood is then perfused in a collagen-coated analysis chamber, and differential labeling permits real-time imaging of both platelet and fibrin deposition using fluorescence video microscopy. The system uses only commercially available tools, increasing the chances of standardization. Reconstitution of thrombocytopenic blood with platelets from banked concentrates furthermore models platelet transfusion, proving its use in this research domain. Exemplary data demonstrated that coagulation onset and fibrin deposition were linearly dependent on the platelet concentration, confirming the relationship between primary and secondary hemostasis in our model. In a timeframe of 16 perfusion min, contact activation did not take place, despite recalcification to normal Ca2+ and Mg2+ levels. When coagulation factor XIIa was inhibited by corn trypsin inhibitor, this time frame was even longer, indicating a considerable dynamic range in which the changes in the procoagulant nature of the platelets can be assessed. Co-immobilization of tissue factor with collagen significantly reduced the time to onset of coagulation, but not its rate. The option to study the tissue factor and/or the contact pathway increases the versatility and utility of the assay.

This paper describes an experimental model of hemostasis that simultaneously measures platelet function and coagulation. Platelet and fibrin fluorescence is measured in real-time, and platelet adhesion rate, coagulation rate, and onset of coagulation are determined. The model is used to determine platelet procoagulant properties under flow in concentrates for transfusion.

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is ...

Production of Genetically Engineered Golden Syrian Hamsters by Pronuclear Injection of the CRISPR/Cas9 Complex

The pronuclear (PN) injection technique was first established in mice to introduce foreign genetic materials into the pronuclei of one-cell stage embryos. The introduced genetic material may integrate into the embryonic genome and generate transgenic animals with foreign genetic information following transfer of the injected embryos to foster mothers. Following the success in mice, PN injection has been applied successfully in many other animal species. Recently, PN injection has been successfully employed to introduce reagents with gene-modifying activities, such as the CRISPR/Cas9 system, to achieve site-specific genetic modifications in several laboratory and farm animal species. In addition to mastering the special set of microinjection skills to produce genetically modified animals by PN injection, researchers must understand the reproduction physiology and behavior of the target species, because each species presents unique challenges. For example, golden Syrian hamster embryos have unique handling requirements in vitro such that PN injection techniques were not possible in this species until recent breakthroughs by our group. With our species-modified PN injection protocol, we have succeeded in producing several gene knockout (KO) and knockin (KI) hamsters, which have been used successfully to model human diseases. Here we describe the PN injection procedure for delivering the CRISPR/Cas9 complex to the zygotes of the hamster, the embryo handling conditions, embryo transfer procedures, and husbandry required to produce genetically modified hamsters.

Pronuclear (PN) injection of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein-9 nuclease (CRISPR/Cas9) system is a highly efficient method for producing genetically engineered golden Syrian hamsters. Herein, we describe the detailed PN injection protocol for the production of gene knockout hamsters with the CRISPR/Cas9 system.

The pronuclear (PN) injection technique was first established in mice to introduce foreign genetic materials into the pronuclei of one-cell stage embryos. ...

Encapsulated Cell Technology for the Delivery of Biologics to the Mouse Eye

Many current therapeutics under development for diseases of the posterior pole of the eye are biologics. These drugs need to be administered frequently, typically via intravitreal injections. Encapsulated cells expressing the biologic of choice are becoming a tool for local protein production and release (e.g., via long-term drug delivery). In addition, encapsulation systems utilize permeable materials that allow diffusion of nutrients, waste, and therapeutic factors into and out of cells. This occurs while masking the cells from the host immune response, avoiding the need for suppression of the host immune system. This protocol describes the use of alginate as a polymer in microencapsulation coupled with the electrospray method as a microencapsulation technique. ARPE-19 cells, a spontaneously arising human RPE cell line, has been used in long-term cell therapy experiments due to its lifetime functionality, and it is used here for encapsulation and delivery of the capsules to mouse eyes. The manuscript summarizes the steps for cell microencapsulation, quality control, and ocular delivery.

Presented here is a protocol for the use of alginate as a polymer in microencapsulation of immortalized cells for long-term delivery of biologics to rodent eyes.

Many current therapeutics under development for diseases of the posterior pole of the eye are biologics. These drugs need to be administered frequently, ...

Optical Imaging of Isolated Murine Ventricular Myocytes

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances in calcium sensitive dyes have permitted the robust optical recording of single cell calcium dynamics, recording of robust transmembrane optical voltage signals has remained difficult. Arguably, this is because of the low single to noise ratio, phototoxicity, and photobleaching of traditional potentiometric dyes. Therefore, single cell voltage measurements have long been confined to the patch clamp technique which while the gold standard, is technically demanding and low throughput. However, with the development of novel potentiometric dyes, large, fast optical responses to changes in voltage can be obtained with little to no phototoxicity and photobleaching. This protocol describes in detail how to isolate adult murine myocytes which can be used for cellular shortening, calcium, and optical voltage measurements. Specifically, the protocol describes how to use a ratiometric calcium dye, a single-excitation calcium dye, and a single excitation voltage dye. This approach can be used to assess the cardiotoxicity and arrhythmogenicity of various chemical agents. While phototoxicity is still an issue at the single cell level, methodology is discussed on how to reduce it.

We present the methodology for the isolation of murine myocytes and how to obtain voltage or calcium traces simultaneously with sarcomere shortening traces using fluorescence photometry with simultaneous digital cell geometry measurements.

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances ...

Microinjection of Corn Planthopper, Peregrinus maidis, Embryos for CRISPR/Cas9 Genome Editing

The corn planthopper, Peregrinus maidis, is&#160;a pest of maize and a vector of several maize viruses. Previously published methods describe the triggering of RNA interference (RNAi) in P. maidis through microinjection of double-stranded RNAs (dsRNAs) into nymphs and adults. Despite the power of RNAi, phenotypes generated via this technique are transient and lack long-term Mendelian inheritance. Therefore, the P. maidis toolbox needs to be expanded to include functional genomic tools that would enable the production of stable mutant strains, opening the door for researchers to bring new control methods to bear on this economically important pest. However, unlike the dsRNAs used for RNAi, the components used in CRISPR/Cas9-based genome editing and germline transformation do not easily cross cell membranes. As a result, plasmid DNAs, RNAs, and/or proteins must be microinjected into embryos before the embryo cellularizes, making the timing of injection a critical factor for success. To that end, an agarose-based egg-lay method was developed to allow embryos to be harvested from P. maidis females at relatively short intervals. Herein are provided detailed protocols for collecting and microinjecting precellular P. maidis embryos with CRISPR components (Cas9 nuclease that has been complexed with guide RNAs), and results of Cas9-based gene knockout of a P. maidis eye-color gene, white, are presented. Although these protocols describe CRISPR/Cas9-genome editing in P. maidis, they can also be used for producing transgenic P. maidis via germline transformation by simply changing the composition of the injection solution.

Microinjection of Corn Planthopper, Peregrinus maidis, Embryos for CRISPR/Cas9 Genome Editing

Herein are protocols for collecting and microinjecting precellular corn planthopper embryos for the purpose of modifying their genome via CRISPR/Cas9-based genome editing or for the addition of marked transposable elements through germline transformation.