Laser device for noninvasive delivery of drugs through the skin

AVCRI/RedEmprendia Project for the Valuation and Commercialization of Research and Development Results (Principal Investigator)
Nov 2010 - Oct 2012


Descrição: final1(ondas de choque).jpgLaserLeap was designed as a non-invasive Class IIa medical device for transdermal or intra-epidermal administration of drugs. Its method of operation is based on the absorption of a fast laser pulse by an appropriate device that transforms the radiative energy (light) into an intense and short duration pressure wave. This pressure wave is like a tsunami that disturbs dramatically the properties of the medium in which it spreads. When a pressure wave with amplitude of hundreds of atmospheres and in a frequency range of megahertz (1 MHz = 106 s-1) spreads through skin, the skin structure is disrupted in a reversible and painless way. In particular, the packing of the 15 to 20 cell layers of the structure of the outer skin, called stratum corneum (SC), is transiently disorganized and becomes more permeable. Thus, it opens a window for the permeation through the skin of molecules and nanostructures such as proteins or plasmids. Just a few minutes later, skin takes over its structure and unique protective properties.

According to one of its specifications, the LaserLeap technique is based on the photoacoustic effect. This effect consists in the production of a pressure wave (acoustic wave), as a result of the rapid transformation of radiative energy (light) into thermal energy by an appropriate dye. This dye absorbs light of a laser pulse, it quickly converts it into heat which is transmitted to the surrounding medium, producing a phase thermal expansion of the medium. A judicious choice of the medium, in particular its thickness and thermal expansion, allows the creation of an acoustic wave with high intensity and the duration of the laser pulse. A good acoustic coupling between the photoacoustic device and the skin promotes the efficient transmission of the pressure wave into the skin and the disruption of the SC compact structure. During that time a drug, in a proper formulation, in contact with skin may spread quickly through the SC, and then passively diffuse through the epidermis. In another of its specifications, the LaserLeap technique uses explosive polymers detonated by the absorption of a laser pulse to produce pressure waves. One of the distinguishing features of the LaserLeap method is the use of low energy lasers. This allows the use of safe, economical, durable and easy to manipulate lasers. It is this feature that allows producing a first competitive device for delivery of drugs based on the action of photoinduced pressure waves.

The administration of drugs through the skin uses almost invariably needles. The replacement of needles by a painless method without risk of contamination or infection, easy to use, economical and environmentally friendly, will certainly revolutionize medicine and cosmetics. The use of LaserLeap can become global in a short time and for a wide variety of products.

Interfaces and Energy Efficiency:
Design, synthesis and photoacoustic characterization of nanostructured materials for energy applications.

PTDC/QUI-QUI/099730/2008 (Principal Investigator)
Feb 2011- Feb 2014


The quest for non-pollutant energy sources and a better use of energy is a worldwide priority, which can only be met investing in knowledge-based energy conversion devices. This project focuses on the basic molecular understanding of the interfaces existing in such devices, aiming at a chemical description of the processes occurring at interfaces. Our success will contribute to the knowledge required to produce more efficient energy conversion devices.

Solar radiation is the most widely available and long-term source of renewable energy, but presently, only a small fraction of this is used in energy conversion devices. Photovoltaic systems (PV) harvest the UV and visible part of the spectrum, corresponding to 58% of the total solar energy density. The remaining 42% correspond to the IR component, and are waste heat in conventional semiconductor-based PV cells. This heat is a major cause of instability and failure of PV systems. The perfect solution for the energy crisis might be in the combination of the two worlds (UV-Vis and IR parts of the solar spectrum) in high-efficiency direct Solar-Thermal Energy Conversion.
Economical collection of the UV-VIS solar radiation may be achieved by dye-sensitized solar cells (DSSC), which are among the most promising solutions for PV energy generation. Waste heat conversion has been focused on a few relatively complex nanomaterials with favorable thermal and electron conduction properties for thermoelectric (TE) applications. A major bottleneck in the development of both DSSC and TE is the (in)efficiency of charge separation processes at the (solid:solid or solid:liquid) interfaces existing in such devices. We assign poor device performance to material interfaces, either due to inefficient electrical conduction, energetic mismatches, or high charge recombination.

In this project we approach the problem of efficiency loss at heterojunctions from a fundamental chemistry perspective, rather than the empirical trial and error method of the current practice. To overcome stability issues in DSSCs, we will explore the potential of several conducting polymers as hole transport medium and investigate the interaction between these and the active dye-sensitized nanoporous TiO2 layer. A global understanding of the problem will be achieved through a rigorous control of all the components of the inorganic-organic interface, and an evaluation of the kinetics of charge transfer processes occurring through such interfaces. Polymers will be tailored to maximize conductivity, while minimizing back electron transfer and recombination.

Thermoelectric materials convert heat into electricity, by taking advantage of the Seebeck principle: when the junctions between two different materials are held at different temperatures, a voltage is generated that is proportional to the temperature difference. Efficient thermoelectric conversion is obtained in the presence of large temperature differences (IR solar emission). We will explore the thermoelectric power of complex cobalt oxides and titanium oxides, as well as of conducting polymers, and investigate their interfacial charge and heat transfer properties as a function of structure and chemical composition. Photoacoustic thermal characterization of the nanomaterials will be related to their micro-structural properties. As Photoacoustic waves cross materials and act as sensors of their entire depth, we will perform subsurface analysis and depth-profiling.

Our approach is enabled by expertise in the synthesis of nanostructured semiconductor metal oxides, preparation of emulsions/pastes that offer controlled deposition of various layers of such materials, synthesis of conducting polymers, and familiarity with a vast array of techniques to analyze materials and interfaces. This confluence of competences and resources is only possible due to a singular collaboration between two University-based research units (CQC and CEMUC) and the R&D efforts of a Portuguese innovation-driven company, Metoxid. Partnerships for basic research between University and Business, although common abroad, are rare in Portugal. We will combine Metoxid’s capacities in Inorganic Synthesis of nanomaterials, with the expertise in Organic Synthesis gathered at the Chemistry Department, to produce new advanced materials. Material characterization will be done using innovative fast laser techniques and state-of-the art equipment, through an interdisciplinary approach that combines Photochemistry, Electrochemistry and Material Science.

The molecular understanding of interfaces will contribute to the design of more efficient energy-conversion devices. We will prepare new materials, to provide the basis for that understanding. Furthermore, we will develop and apply new techniques to investigate the properties of the materials. Our vision is that a tandem system combining solid-state DSSCs and Thermoelectric Materials will efficiently harvest and convert most of the solar spectrum and make economically viable the widespread use of Solar Energy.

Projects Has Team Member

Two photon hybrid photovoltaic cells for solar energy conversion (PTDC/QUI/70637/2006)

Proton photo pumps (POCTI/QUI/55505/2004)

Patterns of reactivity viewed by the Intersection State Model (POCTI/47267/2002)

Photoinduced reactions in supercritical fluids (FCT/PRAXIS/PCEX/QUI/108/96)

Heterocycles molecular modeling and Structure-Reactivity relationships (PRAXIS/QUI/2/2.1/390/94)