Introduction: The delivery bottleneck in CRISPR therapies
CRISPR-based medicines hold the promise of treating a wide range of diseases, but their success hinges on effective delivery. Early efforts relied on viral vectors, especially adeno-associated viruses (AAVs), to ferry genetic material. While AAVs can deliver DNA, their payload size is limited and пациентов often develop immune responses to viral capsids. As the field shifted toward RNA-encoding CRISPR components, researchers faced new challenges: poor cellular uptake, rapid degradation in blood, and potential immunogenicity without a protective carrier. This is where lipid nanoparticles (LNPs) have emerged as a leading non-viral delivery platform for in vivo CRISPR applications.
LNP fundamentals for CRISPR delivery
Composition and mechanism
LNPs are small, uniform particles typically 50–120 nm in diameter. They encapsulate nucleic acids within a lipid shell and are composed of three core components: ionisable lipids, structural lipids (phospholipids and cholesterol), and steric lipids such as PEG-lipids. Ionisable lipids, like ALC-0315™, play a pivotal role. They are pH-responsive: during formulation they carry a positive charge to encapsulate RNA effectively, but become neutral in physiological conditions to minimize toxicity. Upon cellular uptake, the acidic endosomal environment protonates the lipid, promoting endosomal disruption and release of the RNA cargo into the cytoplasm.
PEG-lipids contribute to stability during manufacturing and storage and help modulate in vivo release by shedding from the particle after administration. The careful balance of these components enables efficient, on-target delivery of the CRISPR payload while maintaining safety profile.
Payload evolution and clinical history
The first clinical success of LNPs was in delivering small interfering RNA (siRNA). The FDA-approved Onpattro® (patisiran) in 2018 treated hereditary transthyretin amyloidosis (hATTR) and marked the dawn of LNP-formulated nucleic acid therapeutics. This milestone demonstrated the feasibility of LNPs for large-scale, diverse nucleic acid payloads, paving the way for mRNA vaccines and CRISPR-related modalities. Today, LNPs have supported siRNA therapies, mRNA vaccines (notably for COVID-19), and the co-delivery strategies needed for CRISPR-Cas9 genome editing.
Advantages of LNPs over viral vectors for CRISPR delivery
- Immune considerations: AAV capsids can provoke pre-existing immunity and limit re-dosing. LNPs show a lower immunogenicity profile, enabling multiple administrations and “dosing to effect.”
- Payload flexibility: LNPs can carry larger or more diverse nucleic acid payloads, including mRNA and guide RNA, which is advantageous when delivering CRISPR components beyond what AAVs can accommodate.
- Transient expression: LNP-delivered CRISPR components typically yield high but transient expression, reducing the risk of off-target edits compared to long-term viral expression.
- Manufacturing speed: LNP production is generally faster and more scalable than viral vector manufacturing, with potential workflows capable of rapid, even patient-specific, assembly.
Current challenges and promising directions
Systemic LNP delivery tends to accumulate in the liver, which is excellent for liver-targeted diseases but limits editing in other tissues. Researchers are exploring strategies to broaden tissue targeting, including DARPin-conjugated LNPs that enhance binding and uptake in non-hepatic cells, such as CD8+ T cells, achieving high expression levels in targeted populations.
Safety and repeat dosing remain priorities. Studies in non-human primates are examining pharmacokinetics, pharmacodynamics, and safety under repeated dosing to establish predictable safety profiles as LNP-based CRISPR therapies evolve. The goal is to enable broader access while maintaining rigorous safety standards.
A landmark step: personalised, bedside CRISPR therapy
In 2025, a world-first, in-human, personalised CRISPR therapy for an infant with severe carbamoyl-phosphate synthetase 1 deficiency was delivered via LNPs. The treatment, developed by the Children’s Hospital of Philadelphia and the University of Pennsylvania, used an Acuitas Therapeutics LNP formulation containing ionisable lipid ALC-0307™ and PEG-lipid ALC-0159™. Three escalating doses were administered without serious adverse events, completed within six months. This case establishes a clinical blueprint for rapid, personalised CRISPR therapies and underscores the value of cross-functional partnerships with payload manufacturers to accelerate development and manufacturing timelines.
Emerging applications and future directions
As LNP technology evolves, researchers are expanding beyond liver-targeted editing. DARPin-conjugated LNPs and other targeting strategies hold potential for treating oncology, cardiovascular diseases, and other genetic disorders. The development of predictable safety profiles, scalable manufacturing, and lower costs could make CRISPR medicines accessible to a broader patient population, addressing a critical barrier to care. Ongoing collaborations between developers, manufacturers, and regulatory bodies will be essential to deliver on the promise of LNP-CRISPR therapies.
Conclusion: a delivery platform driving the CRISPR era
Lipid nanoparticles have emerged as a cornerstone technology in the evolution of CRISPR medicines. By combining efficient, scalable delivery with a favorable safety and dosing profile, LNPs enable more flexible, rapid, and personalized gene editing. As research continues to expand tissue targeting, safety validation, and manufacturing readiness, LNP-based CRISPR therapies are positioned to transform treatment paradigms for a wide array of diseases.
