Protein Kinase C-delta Inhibitor Peptide Formulation using Gold Nanoparticles
March 9th, 2019
We have previously used a gold nanoparticle peptide hybrid to intravenously deliver a synthetic peptide, protein kinase C-delta inhibitor, which reduced ischemia-reperfusion-induced acute lung injury. Here we show the detailed protocol of the drug formulation. Other intracellular peptides can be formulated similarly.
Our unique drug delivery system, which uses 20 nanometer gold particles in two specific short peptides, can stabilize gold nano particles in physiological solution and enhance its cellular uptake, and thus, effectively deliver peptide-based or other drugs into cells. Our GNP peptide hybrid is easy to synthesize and stable. By using gold nanoparticle peptide hybrid as drug carriers, we can transfer peptide drugs into the cells effectively and in abundance.
We treated ischemia-reperfusion injury in the lungs with our GNP/PKCi hybrid. GNP brings PKC inhibitor peptides into the cytoplasm. This delivery method was able to reduce more severe lung injury using a lower dosage of PKCi than other delivery methods.
To begin this procedure, retrieve the peptides from a freezer at minus 20 degrees Celsius, and thaw them at room temperature. Use a micro scale to weigh 0.01 gram of each thawed peptide, and transfer each peptide into a separate 50 milliliter conical tube. Add 18.74 milliliters of deionized water to the P2 tube, and 16.93 milliliters of deionized water to the P4 tube.
Add 8.21 milliliters of 50%acetonitrile diluted in deionized water to the PKC delta inhibitor tube. Vortex the peptide solutions briefly. Then place the tubes into a sonicator at 40 megahertz for five minutes.
After this, transfer the solutions to a biosafety cabinet. It is critical to put the 50 mL conical tube in a sonicator for five minutes. If this step is skipped, the GNP/PKCi will form aggregations.
Transfer one milliliter of each peptide solution to its own new 50 milliliter conical tube. Add 19 milliliters of deionized water to the tubes containing P2 and P4.And add 19 milliliters of 50%acetonitrile to the tube containing PKC delta inhibitor. Add 475 milliliters of the P2 solution, 25 microliters of the P4 solution, 500 microliters of the PKC delta inhibitor solution to a 15 milliliter tube.
Then add nine milliliters of a 20 nanometer GNP solution to the same tube. Remove the combined solution from the biosafety cabinet and wrap the tube in aluminum foil. Place the tube on a shaker overnight.
The next day, return the samples to the biosafety cabinet. Transfer one milliliter aliquots of the GNP/PKCi solution into 1.5 milliliter micro tubes. Centrifuge the micro tubes at a micro centrifuge at 15294 times g and at four degrees Celsius for 30 minutes.
Transfer the micro tubes back into the biosafety cabinet, and remove the supernatent from each tube, while ensuring the GNP pellet is not disturbed. Resuspend each pellet in the desired solvent according to the concentration required. To assess the GNP/PKCi hybrid solubility, pour 0.5 milliliters of the GNP/PKCi solution into an accrual cuvette.
Place the cuvette on a UV-Vis spectrophotometer and test the peak absorption. In this study, protein kinase C-delta inhibitor is conjugated with gold nanoparticles to form a GNP/PKCi hybrid. Care must be taken with evaluating the biophysical properties of the hybrid, as gold nanoparticles tend to aggregate in a solvent.
When the nanoparticles aggregate, the color of the solution will change from pink to purple. The samples are analyzed with a UV-Vis spectrophotometer which is able to detect with a high degree of sensitivity. If the hybrid is not aggregated, the peak of an absorption should be at 525 nanometers.
If the GNP is aggregated, the peak of absorption will be shifted to the right. As can be seen, when aggregates have formed, the delta optical density decreases. When formulating the GNP peptide hybrids, it is important to remember the ratio of peptides to GNP solution should be one to nine.
This GNP/PKCi formula can be used for ischemia-reperfusion injury in organ systems other than the lung. Any peptides can attach to GNP if those peptides have a cysteine residue at the N-terminus. This means GNP peptide hybrid can be used to transport other peptide drugs into the cell.
Rationally designed peptides are new technology that can brought specific protein-protein interaction inside those cells. This technique, developed here, can be used for delivery of new peptide drugs or for modified versions of existing drugs.
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Overview
This study presents a novel drug delivery system utilizing gold nanoparticle peptide hybrids to effectively deliver protein kinase C-delta inhibitors for reducing ischemia-reperfusion-induced acute lung injury. The method enhances cellular uptake and stability of the peptides, allowing for effective treatment with lower dosages.
Key Study Components
Area of Science
- Drug delivery systems
- Nanotechnology
- Acute lung injury treatment
Background
- Gold nanoparticles can stabilize peptides in physiological solutions.
- Peptide-based drugs often face challenges in cellular delivery.
- Ischemia-reperfusion injury is a significant cause of lung damage.
- Effective drug delivery methods can improve treatment outcomes.
Purpose of Study
- To develop a stable and effective drug delivery system using gold nanoparticle peptide hybrids.
- To demonstrate the efficacy of this system in treating lung injury.
- To provide a detailed protocol for synthesizing the drug formulation.
Methods Used
- Synthesis of gold nanoparticle peptide hybrids.
- Intravenous delivery of the hybrid to target lung cells.
- Assessment of cellular uptake and stability in physiological conditions.
- Evaluation of treatment efficacy in ischemia-reperfusion injury models.
Main Results
- The GNP/PKCi hybrid effectively delivered peptide drugs into cells.
- Lower dosages of PKCi resulted in reduced lung injury compared to other methods.
- The system demonstrated high stability and ease of synthesis.
- Enhanced cellular uptake was confirmed through experimental analysis.
Conclusions
- The gold nanoparticle peptide hybrid is a promising drug delivery system.
- This method can significantly improve treatment for acute lung injury.
- Further research may expand its application to other peptide-based drugs.
Frequently Asked Questions
Executive Industry Relevance
Gold nanoparticle (GNP) peptide hybrids offer a modular platform for intracellular delivery of peptide-based inhibitors, addressing key challenges in stability and cellular uptake. This technology enables precise delivery of rationally designed peptides, supporting early-stage target validation and mechanistic de-risking in drug discovery. Its adaptability across peptide cargos positions it as a reusable capability for portfolio-wide translational research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables functional interrogation of intracellular targets using peptide inhibitors.
- Supports mechanistic de-risking by ensuring efficient cytoplasmic delivery of candidate molecules.
- Facilitates predictive confidence in target engagement through quantitative uptake and stability assessments.
Screening & Assay Development
- Provides a standardized platform for preparing peptide-GNP conjugates with reproducible physiochemical properties.
- Enables quantitative assessment of nanoparticle aggregation and peptide delivery using UV-Vis spectrophotometry.
- Supports assay scalability and platform reuse for diverse peptide sequences with N-terminal cysteine residues.
Translational & Preclinical Research
- Demonstrates in vivo delivery and efficacy in organ injury models, supporting translational continuity.
- Allows adaptation for other organ systems and peptide-based therapeutics as supported by physiochemical compatibility.
- Reduces biological risk by enabling lower dosing and minimizing off-target effects compared to traditional carriers.
Pipeline & Workflow Integration
This GNP-peptide hybrid formulation bridges early discovery, lead identification, and preclinical validation by enabling robust intracellular delivery and quantitative characterization of peptide therapeutics.
- Discovery Biology: Supports hypothesis testing and pathway clarification via efficient intracellular delivery of functional peptides.
- Screening: Delivers reproducible, quantitative readouts of nanoparticle stability and peptide conjugation.
- Analytics: Utilizes UV-Vis spectrophotometry for sensitive detection of aggregation and delivery efficiency.
- Translational Research: Demonstrates in vivo applicability and adaptability to multiple organ systems.
- Enterprise Reuse: Offers a generalizable delivery platform for a range of peptide-based drug candidates.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in intracellular target validation and mechanistic studies.
- Operational Value: Standardizes peptide delivery workflows and enhances reproducibility across R&D teams.
- Strategic Value: Enables risk-adjusted go/no-go decisions by providing robust delivery and quantitative analytics.
- Portfolio Impact: Supports prioritization of peptide therapeutics with improved delivery and reduced off-target risk.
Implementation Considerations
- Requires expertise in nanoparticle synthesis and peptide conjugation chemistry.
- Needs access to analytical instrumentation such as UV-Vis spectrophotometers for aggregation assessment.
- Demands cross-team standardization of peptide-to-GNP ratios and solvent conditions.
- Adaptable to peptides with N-terminal cysteine residues for broad applicability.
- Aggregation risk must be managed through careful protocol adherence and physiochemical monitoring.
