9. Bionanotechnology Repetition from the Last Lecture • What are the 2 different types of catalysis (in terms of catalyst and reactant state)? • What is chemical selectivity? Give an example. • What is a hydrogen cell and how does it work? • What limits the capacity of Li-ion batteries and the rate of charge? • How can we generate electricity from "waste" energy? Molecular Biology A branch of biology that studies the cell biological processes at the molecular level (i.e. at nm). The cell itself can be considered a complex nanoscale device. • Mitochondria - energy production • Ribosomes - production of proteins (molecular motors) from amino acids linked by peptide bonds. • DNA-a program for making proteins Mitochondria Nuclear membrane Ribosomes Nucleus 3 JUL1TI Cell membrane 3 busies : I cudon 2 nm Nanobiology • Applying nanotechnology to biological systems with a view to achieving practical results • Separation and measurement of biological product properties (fluorescence using quantum dots, molecule mass measurement,...) • Biological material modification to improve their properties • Biomolecule manipulation (micro and nanofluidics, optical tweezers) • Use of biological molecules for new sensors or new applications Optical Tweezers A highly focused laser beam can stabilize small translucent objects (e.g. spheres) in its focus. The biomolecule stuck to the object's surface in the laser focus can then be manipulated -e.g. untangling a DNA molecule. dp. ; \/ ! -dp, net force optical trap Laser beam https://physicsworld.eom/a/optical-tweezers-where-physics-meets-biology/ https://www.researchgate.net/publication/271222429_Progress_of_new_label-free_techniques_for_biosensors_A_review DNA Nanostructures The DNA molecule can be programmed to form junctions at a defined location in the polymer. This is very advantageous for the formation of self-organized nanostructures. DNA BASE PAIRS H> -ft-- N M »0 » IGACG T AC C KA TCAAOGUk CTAOG A + U.C. II ACiCTCA I ACCCTAi HYDROGEN BONDING \ I ... | MA II.A I (.< AACGTACTACCAfiTCCfliCAA'P i . VI'G N T . A C . G j"c". B GCA C GlA G T T G A T A CCG CGTGCTCA C • G C . G G • C A • T ACT |A T G| G C -7 IV . i • A https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4141725/ DNA Origami • After synthesizing the appropriate DNA parts, the entire complex structure is formed in solution with virtually 100% yield. • DNA origami - one large DNA molecule folded by small DNA sections (helper strands) into the desired shape. The remaining sections are filled with DNA but without crosslinking. 0 © ® & .ncbi.nlm.nih.gov/pmc/articles/PMC4141725/ DNA Origami 6803 Biomimetics • Emulation of the natural constructs for the purpose of use in new fields • Macro biomimetics-bird wings, composites, dolphin locomotion (boundary layer manipulation in liquid), robotics • Micro/nano biomimetics - drug development, neural networks, lotus effect, gecko effect, microactuators, hard structures,... • Wing: • Aspirin: Acetylsalicylic acid derived from salicylic acid (an extract of willow). Phenol-free, it no longer causes stomach ulcers with long-term use. https://theaviationistxom/2013/03/19/an-unbelievable-i^ Platelet Hybrid Film Due to its microstructure, the mussel shell is about 3,000 times stronger than the CaC03 from which it is made. The layers of aragonite platelets are glued together by a thin layer of protein that allows the layers to slide slightly over each other. Adjacent platelets are not glued together. Thus, a rupture of one platelet does not spread to the other platelets. https://www.mdpi.eom/2079-4991/3/2/242/htm https://www.science.org/doi/10.1126/science.1148726 Aiaeouite platelet Of ganic matrix gap Cross SCl'llOll .Uagonite platelet layer Dispersion in ethanol 200 nm & dropwise addition onto water 5 -10 pm Mineral bruise C eiitial res inn Organic man Ix ^lieet Sonication for 15 min 6 Transfer of platelet monolayer I Substrate | Lotus Effect - Superhybrophobicity The water repellency and self-cleaning effect of lotus leaves, rose petals or insect legs is due to their nanostructure - needlelike structure. It keeps the leaves clean and dry. The rolling droplet packs dirt onto itself. dust particles https://wwwTesearchgate.net/publication/333974770_Bio-inspired_Sustainable_and_Durable_Superhydrophobic_M https://wwwTesearchgate.net/publication/260168901_A_low_cost_safe_disposable_rapid_and_self-sustainable_paper-based_platform_for_diagnostic_tes https://br.depositphotos.com/stock-photos/gerris-lacustris.html Gecko Effect • Geckos can climb vertically and on glass without any adhesive. This is made possible by the "suction" lamellae on their feet (about 5,000 mm2). The lamellae do not stick to each other. https://royalsocietypublishing.org/ doi/10.1098/rsta.2007.2173 Gecko Adhesion Mechanism • The adhesion is determined by Van der Waals (physical) forces after the spatulae are pressed against the surface. The gecko detaches from the surface by lifting the spatulae at an angle. • Van der Waals forces - a common name for short range forces (1/r7). They include: • Keesom force - between molecules with permanent dipole moments • Debye force - a molecule with a permanent dipole moment induces a dipole moment in an adjacent molecule by polarization • London dispersion force - instantaneous dipole moment given by the motion of electrons in the molecule. They are present in all molecular interactions. z □> z s ■d □ 16 3S Perpendicular preload force (jjN) https://www.nature.com/articles/35015073 Medical Applications of Gecko Adhesion • In surgery, there is a demand for a strong biodegradable patch that adapts to various mechanical deformations (e.g. heart) while still retaining adhesion to the tissue it covers. • An example from MIT - a gecko adhesive made from the biodegradable elastomer PGSA - poly (glycerol-co-sebacate acrylate): (a) Nanocasting into a photolithographically prepared Si mold + UV curing + spin coating with dextran (adhesive) (b) Various gecko structures (c) (d) Adhesion test results Length (//m) 1 2 3 Length (pm) 1 2 3 0 0.2 0.4 0.6 Tip Diameter / Base Diameter '.ncbi.nlm.nih.gov/pmc/articles/PMC2268132/ Medical Nanotechnology • The modern understanding of medicine is based on the idea of the metabolism control by a complex communication network mediated by molecules (cellular communication) that control and coordinate cellular activities. • Nanomedical research focuses on: • New materials for restoring cell growth (scaffolding) and tissue repair (nerve repair, •••) • Improving diagnostics and imaging (nanomagnetism, quantum dots, biological sensors,...) • Improving drug delivery (targeted dosing, pacemakers,...) • Understanding and controlling biomolecular mechanisms (tailor-made molecular enzymes) • Discovery of new therapeutic effects of nanoscale systems (including biosystems) -e.g. ferrofluid in the treatment of retinal detachment, plasmons, new types of patches,... Nanoencapsulation • For example, insulin is administered subcutaneously because it would not pass through the digestive tract. Drugs to the brain are unable to cross the blood-brain barrier. Coating the molecule with a suitable material -nanoencapsulation - is one possible solution for drug delivery. • It is also possible to encapsulate living cells to avoid an immune reaction of the organism. E.g. pancreatic beta cells producing insulin in a self-contained container. « • *■ • • c d < 1 ■ g -• *m c https://pubs.rsc.org/en/content/articlelanding/2011/lc/c0lc00368a Restoring Damaged Peripheral Nerves The peripheral nervous system has the ability to regenerate axonal nerve fibres (axons) over short distances. Regeneration over longer distances can be promoted by a suitable support structure (tube), which can also be impregnated with growth activators. variations in conduit design surface funclionalization https://royalsocietypublishing.org/doi/10.1098/rsif.2011.0438 (1) fluid phase regeneration within a tube >°b o°b I accumulation of neurotrophic factors and KCM (2) matrix phase molecules ( ^^) cellular phase fibrin cable formation (4) axonal phase Schwann celt migration, proliferation and alignment and tissue cable formation / — (5) myelination phase growth of daughter axons (proximal to distal) across de novo tissue cable myelination of regenerated immature axons form ins* mature axonal fibres Artificial (Electronic) Skin • Human skin • Largest organ with an area of ~1.7 m2 • Protects against microbes, prevents infection, metabolizes vitamin Dto build calcium into bones, regulates body temperature. • It's a huge sensor - pressure, heat, cold, pain. • Elastic, self-renewing (dead cells on the surface are gradually renewed by cells coming from deeper layers). pacinian corpuscle .wikiskripta.eu/w/K%C5%AF%C5%BEe hair shall stratum corneum pigment layer itratum germinativum {stratum spinosum stratum basale arrector pili muscle sebaceous gland hair follicle papilla of hair nerve fiber "" blood and lymph vessels sweat pore dermal papilla sensory nerve ending for touch EPIDERMIS -DtRMIS sin., mis (hypodermis) Artificial (Electronic) Skin • The concept of artificial skin was developed for robotics - the ability to perceive pressure - the problem of lifting an egg. Most standard robots only have a rudimentary sensor - there is a yes/no contact. • Further development for prosthetics - there must be a sensor at least • Elastic • With full sensitivity in the range of 5 - 100 mN with a linear response • With a spatial resolution of 1 - 2 mm https://www.semanticscholar.org/paper/Flexible-Electronic-Skin-Thakur-Dofe/647b6302b5c3a67ba21259763172 Artificial (Electronic) Skin Using the similarity of the sensor apparatus with the properties of organic FET transistors. Substrata vi. Pores, Papilla«, Karatinocytei ( Function: Act •» Burner, Membrane ] Electrodes vs Blood Vessels, Nerves I Function: Collect information ] Semiconductor, Ditltctric vs. Hair, Corpuscles, Glands ( Function: Trantduca Information ] (A) Dielectric Elastomer (B) Semiconductor Dielectric Substrata 3 cm: Organic semiconductor Nanotechnology and Nanosensors Part 2, Technion - Israel Institute of Technology, Coursera Artificial (Electronic) Skin Using functionalized nanoparticles or carbon nanotubes (tunneling current dependent on particle distance) A. As-deposited C. Relaxed Carbon nanotube bundles: Random orientation B. Stretched Tension Buckled along stretched axis D. Biaxilly stretched: relaxed Stretched-aligned Buckled in all directions Revolution of morphology of films of carbon nanotubes with: (a) stretching; (b) under strain; (c) stretched and released along one axis; (d) and stretched and released along two axes. logy and Nanosensors Part 2, Technion - Israel Institute of Technology, Coursera Conclusion • Nanotechnology in molecular biology (itself a "nano" discipline) seeks, among other things, to combine the proven functionality of biological systems with the capabilities of microelectronic technologies. • Biomimetics uses reverse engineering methods to understand systems developed by evolution over 4 billion years. Nanotechnology allows us to mimic many systems. • Medical nanotechnology enables active treatment at the macromolecular level and the design of qualitatively new implants.