Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Robert E. Sievers

Research Interests

Professor Sievers is studying analytical chemistry, pharmaceutical science, aerosols, microparticles and nanoparticles, inhalable vaccines and antibiotics, and supercritical fluids.

For more than 40 years the Sievers research group has conducted fundamental and applied studies of the formation of nanoparticle and microparticle aerosols and innovative methods for synthesis, purification, characterization of useful materials. Carbon dioxide-assisted nebulization provides superior aerosols. Sievers is collaborating with medical professionals and engineers to develop new methods for delivery of aerosol particles useful in direct and painless administration of therapeutic drugs and vaccines by inhalation and by sublingual delivery. The drugs are dissolved or suspended in supercritical fluids, and unusually small aerosol particles are formed by rapid decompression to facilitate delivery of the aerosol particles to the alveoli and to allow rapid uptake by the lungs and respiratory tracts. Formation of fine aerosols is expected to become increasingly important in the treatment or vaccination against measles, influenza, infections, stress, COPD, and asthma.

The simultaneous stabilization, drying, and micronization of vaccines, antibodies, proteins, antibiotics, and anti-inflammatory pharmaceuticals and other products of the biotechnology revolution are under study. Two of the fourteen "Grand Challenges" identified by the Bill and Melinda Gates Foundation and the NIH Foundation as critical to world health have been addressed by the Sievers group: needle-free administration of vaccines (by pulmonary or nasal aerosols), and vaccines stable for long term storage.

In technology transfer, Sievers Instruments, Inc. and successor companies, Ionics-Sievers and GE ANalytical, have manufactured 30,000 detectors and analyzers for 10,000 users for applications in trace analysis for environmental, water treatment, energy, pharmaceutical, and other applications from 1984 until the present. 

Current Research

Development of needle-free and water-free inhalable dry powder aerosol vaccines and pharmaceuticals

Inhalable dry powder aerosol vaccines and pharmaceuticals require no needle, no purified water for reconstitution, and no electricity or batteries for delivery, which makes them especially useful in developing countries. Working in Prof. Sievers’ Global Health Program in CIRES, a team developed the first dry powder aerosol measlesvaccine to complete Phase I clinical trials without any adverse events.

We have invented and developed a special form of spray drying, Carbon Dioxide Assisted Nebulization with a Bubble Dryer (CAN-BD), that produces aerosol microparticles small enough (1-5 microns aerodynamic diameter) to be distributed throughout the moist respiratory tracts of humans and test animals in which diseases can be prevented or alleviated.

This dry powder aerosol vaccine has been administered to 40 human volunteers without any serious adverse events observed while following the patients 180 days after this Phase I safety clinical trial began in India. There have been recent outbreaks of measles in Italy and Eastern Europe within the last 6 months due to war in the Middle East and unvaccinated refugees spreading active virus to populations not adequately protected by conventional forms of vaccination in times of turmoil. While the funds provided for clincal trials for safety in adults by the Gates Foundation and the Centers for Disease Control (CDC) were adequate earlier, these were exhausted before tests in children could be undertaken. 


Click here for list of publications

Robert Sievers demonstrates easy vaccination by inhalation of dry powder aerosol vaccines in a needle-free inhaler that he co-invented. Photo credit: Glen Asakawa/CU Boulder

Honors and Awards

  • Tswett Chromatography Medallist, 1981
  • American Chemical Society Colorado Section Award, 1985
  • Dimick Award in Chromatography, 1992
  • Thomas Jefferson Award, 2001
  • Robert Stearns Award, 2003
  • Pinnacle of Inventorship Award, 2004
  • ACS Astellas Prize in Public Health, 2008
  • Governor's Award for Research Impact, 2009