A central theme in pharmaceutical research is controlling drug release, i.e. optimizing the pharmacokinetic (PK) profiles through, e.g. sustained release matrices. With advances in materials, modern drug delivery systems are developed to work in a pre-programmed, controlled manner. Another aspect is to control the location of drug action by utilizing targeted nanoparticles.

Nanofibrillar cellulose has attracted a lot of attention as a natural alternative for these purposes. We have evaluated the potential of nanocellulose for controlled drug delivery for several years. Several PhD thesis have been completed in the group and the work still continues for example in the development of modulated release formualtions or activatable drug delivery systems.

We are also studying other ways to control drug release rate. These include iontophoresis, drug nanoparticles, liposomes, polymeric carriers, and other supramolecular systems. Especially liposomes with various coatings are being actively studied in the group.

Examples of our publications:

  1. Auvinen, V.-V., et al., "Modulating sustained drug release from nanocellulose hydrogel by adjusting the inner geometry of implantable capsules", J. Drug Del. Sci. Tech., 2020.
  2. Paukkonen, H., et al., "Nanofibrillar cellulose hydrogels and reconstructed hydrogels as matrices for controlled drug release", Int. J. Pharm, 2017.
  3. Valo, H., et al., "Drug release from nanoparticles embedded in four different nanofibrillar cellulose aerogels", Eur. J. Pharm. Sci., 2013.
  4. Kolakovic, R., et al., "Nanofibrillar cellulose films for controlled drug delivery", Eur. J. Pharm. Biopharm., 2012.

A particular area of interest is also light-triggered release from liposomal drug carriers. We consider the light to be the most flexible drug-release trigger for advanced drug delivery systems. Light can be used to both trigger and subsequently control the drug release with extreme spatial and temporal resolution. To have the best tissue penetration, we are focusing on red-light activatable nanocarriers, or in situ generation of blue light. Modern ultrathin light guides also enable the treatment of deeper tissues with minimal surgery.

The system of a particular focus for us has been Indocyanine Green (ICG) sensitized purpose-designed liposomes for various challenging target sites. It has been shown to be efficient with even low light intensities and the released drug amount can be readily controlled by the light irradation time.

Examples of our publications:

  1. Kari, O., et al., "Light-Activated Liposomes Coated with Hyaluronic Acid as a Potential Drug Delivery System", Pharmaceutics, 2020.
  2. Lajunen, T., et al., "The effect of light sensitizer localization on the stability of indocyanine green liposomes", J. Controlled Rel., 2018.
  3. Lajunen, T., et al., "Indocyanine Green-Loaded Liposomes for Light-Triggered Drug Release", Mol. Pharm., 2016.
  4. Paasonen, L., et al., "Gold nanoparticles enable selective light-induced contents release from liposomes", J. Controlled Rel., 2007.

We are developing methods to track and analyze the interactions of drug nanocarriers and cells. One tool in particular is Fluorescence Lifetime Microscope. Here we work closely together with the Supramolecular chemistry of bio- and nanomaterials group at Tampere University, where advanced time-resolved spectroscopy and imaging can be done. We are also actively collaborating with many other laboratories and universities in order to have access a very wide range of instrumentation.

Photon upconversion is also studied under this theme, with a goal of achieving blue-light generation in biological environments. For example, porphyrin derivatives can be used to absorb red light, transfer the energy through triplet-triplet energy transfer to another molecules, which can emit blue light. Out current systems are able to have high quantum yields, with bright blue emission visible to the naked eye.

Examples of our publications:

  1. Lisitsyna, E., et al., "Deciphering Multiple Critical Parameters of Polymeric Self-Assembly by Fluorescence Spectroscopy of a Single Molecular Rotor BODIPY-C12", Macromolecules, 2021
  2. Isokuortti, J., et al., "Endothermic and Exothermic Energy Transfer Made Equally Efficient for Triplet-Triplet Annihilation Upconversion", J. Phys. Chem. Lett., 2020.
  3. Durandin, N., et al., "Efficient photon upconversion at remarkably low annihilator concentrations in a liquid polymer matrix: when less is more", Chem. Comm., 2018.
  4. Saari, H., et al., "FLIM reveals alternative EV-mediated cellular up-take pathways of paclitaxel", J. Controlled Rel., 2018.