Summer Intern | Medicinal Chemistry

Headquartered in Carlsbad, California, and with offices in Boston, Massachusetts, and Dublin, Ireland, Ionis has been at work for more than three decades discovering medical breakthroughs that have redefined life for people with serious diseases. We’re pioneers in RNA-targeted medicines, and our platform continues to revolutionize drug discovery and transform lives for patients with unmet needs. With multiple marketed medicines and a leading pipeline in neurology, cardiology and select areas of high patient needs, we continue to drive innovation in RNA therapies in addition to advancing new approaches in gene editing to provide greater value to patients and are well positioned financially to deliver on our strategic goals.

At Ionis, we pride ourselves on cultivating a challenging, motivating and rewarding environment that fosters innovation and scientific excellence. We know that our success is a direct result of the exceptional talents and dedication of our employees.

With an unprecedented opportunity to change the course of human health, we look to add diverse individuals, skill sets and perspectives to our exceptional team. We continue to invest time, money and energy into making our onsite, hybrid and remote work environments a place where solid and lasting relationships are built and where our culture and employees can thrive.

We’re building on our rich history, and we believe our greatest achievements are ahead of us. If you’re passionate about the opportunity to have meaningful impact on patients in need, we invite you to apply and join us. Experience and contribute to our unique culture while you develop and expand your career!

The summer intern will work on a cutting-edge ligand engineering project focused on optimizing Blood-Brain Barrier (BBB) ligands for the delivery of oligonucleotides. This involves applying protein engineering techniques and leveraging yeast surface display technology to identify novel clones with improved central nervous system (CNS) delivery of oligonucleotide payloads.

• Protein Engineering:
  Perform high-throughput mutational scanning on BBB ligands to improve the delivery of oligonucleotides to the CNS.
• Yeast Culture Operation, Molecular Biology, and Surface Display:
  Implement and utilize yeast display platforms to present engineered variants for screening.
• Conjugation Analysis:
  Conjugate variants to oligonucleotides and assess conjugation efficiency.
• Functional Evaluation:
  Use multi-parameter flow cytometry to evaluate expression levels, antigen-binding functionality, and conjugation success.
• Data Interpretation:
  Analyze experimental results to identify mutants with improved CNS delivery.

• Hands-on experience in molecular biology, protein biochemistry, and flow cytometry.
• Exposure to advanced antibody engineering strategies and ligand design.
• Opportunity to contribute to a project with potential for publication and real-world impact.

• Strong interest in biotechnology, molecular biology, or related fields.
• Ability to work independently and collaboratively in a research environment.
• Attention to detail and willingness to learn new techniques.
• Commitment to scientific rigor and problem-solving.

• The program is designed to complement a student’s undergraduate and/or graduate studies with relevant, hands‑on industry experience
• Ionis offers paid positions
• Weekly stipend (for onsite interns only)
• Professional Networking
• End‑of‑program project presentations
• Housing/Travel assistance available for eligible, out‑of‑area interns
• Networking and bonding social events
• Interaction with diverse and motivated teams/departments

• MUST be currently enrolled in a U.S. Undergraduate and/or Graduate Degree Program and not graduating prior to the completion of the Ionis internship.
• MUST be able to begin internship between 6/8 and 8/14/2026.
• MUST be able and willing to remain in program through at least 8/14/2026.
• MUST be able and willing to commit to a minimum 40‑hour work week.

Visit our website  for more information about Ionis and to apply for this position

The pay scale for this position is $18 to $23 per hour.

NO PHONE CALLS PLEASE. PRINCIPALS ONLY. Final date to receive applications IS April 30, 2026. PLEASE INCLUDE A COVER LETTER RELEVANT TO THE POSITION APPLYING FOR. THE EVALUATION PROCESS MAY COMMENCE PRIOR TO THIS DEADLINE.

Ionis Pharmaceuticals, Inc. and all its subsidiaries are proud to be EEO employers.

Equal Opportunity Employer
This employer is required to notify all applicants of their rights pursuant to federal employment laws. For further information, please review the Know Your Rights notice from the Department of Labor.