Biomedical and Energy Applications of Bare Nanoparticle Building Blocks made by Lasers in Liquids
Prof. Stephan Barcikowski, Universität Duisburg-Essen
Size matters. After decades of intensive nanoresearch, nanoparticles are widely implemented as functional elements on surfaces, into volumes and as nanohybrids, with biomedical application prospects as drug releasing nanoparticle-polymer-composites or nanoparticle-bioconjugates and energy application by heterogeneous catalysts.
However, nowadays only a limited variety of materials that may be integrated into advanced functional products are available: Nanoparticles synthesized by conventional gas phase processes are often agglomerated to micropowders that are hardly re-dispersible into functional matrices, and chemical methods often lead to impurities of the nanoparticle colloids caused by additives and precursor reaction products. These residuals may desactivate the nanoparticle´s surface and require cleaning steps which compromise the colzloidal quality or yield. As alternative synthesis route, laser ablation of solids in liquids has proven its capability to generate nanoparticles with utmost purity, being highly affine for conjugation, both with hard and soft matter:
Related to chemical energy conversion application, deposition of naked nanoparticles on inorganic and carbon supports creates heterogeneous catalysts with 100% cumulative yield, with mass loading up to 60% adjustable without changing catalyst particle size.
Scale-up of the method is shown at the example of polymer matrix embedding, fabricating kilogram scale of polymer membrane nanocomposites essential in artificial lung implants.
Laser-generated gold and monophasic gold-silver-alloy nanoparticles particularly profit from purity, which allows their application in biomedicine without cross effects. Hence this reference material is used to model unintended implant debris toxicity using a very sensitive biofunctional system: mammalian reproduction biology.
Also conjugation to biomoleclules starts from scratch (the bare surface), allowing preecise control of ligand load. Intendetly, charge balancing of gold nanoprobes conjugated by oppositely charged ligands (DNA/LNA with amphhiphilic cell penetrating peptides) allowed to study nanoparticle assembly at distinct membrane sites and shutteling non-endocytotically into sperms, through acrosome reaction.
Barcikowski, S. ; Compagnini, G.: Advanced Nanoparticle Generation and Excitation by Lasers in Liquids. Phys. Chem. Chem. Phys. 15 (2013), 9, 3022-3026
Rehbock, C. ; Jakobi, J. ; Gamrad, L. ; Van der Meer, S. ; Tiedemann, D. ; Taylor, U. ; Kues, W. ; Rath, D. ; Barcikowski, S.: Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays. Beilstein Journal of Nanotechn. 5 (2014), 1523-1541
Merk, V. ; Rehbock, C. ; Becker, F. ; Hagemann, U. ; Nienhaus, H. ; Barcikowski, S.: In Situ Non-DLVO Stabilization of Surfactant-Free, Plasmonic Gold Nanoparticles: Effect of Hofmeister's Anions. Langmuir 30 (2014),15,4213-4222.
YouTube Channel (of published videos shown during the talk): youtube.com/nanofunction
Gamrad, L.; Rehbock, C.; Krawinkel, J.; Tumursukh, B.; Heisterkamp, A.; Barcikowski, S.; Charge Balancing of Model Gold-Nanoparticle-Peptide Conjugates Controlled by the Peptide's Net Charge and the Ligand to Nanoparticle Ratio. Journal of Physical Chemistry C (2014), 118 (19), 10302-10313.
Barchanski, A.; Taylor, U.; Sajti, C. L.; Gamrad, L.; Kues, W. A.; Rath, D. Barcikowski, S.: Bioconjugated gold nanoparticles penetrate into spermatozoa depending on plasma membrane status; Journal of biomedical nanotechnology, vol. 11 (2015) ; doi:10.1166/jbn.2015.2094
Marzun, G. ; Streich, C. ; Jendrzej, S. ; Barcikowski, S. ; Wagener, P.: Adsorption of Colloidal Platinum Nanoparticles to Supports: Charge Transfer and Effects of Electrostatic and Steric Interactions. Langmuir 30 (2014), 40, 11928-11939