Surface Engineering Research for Bio-Medical & Medical Electronics Applications in 2010: NanoBonding™ and VitreOX™

FACULTY AND STUDENTS + Department of Physics, ASU Prof. Nicole Herbots * , emeritus Prof. R.J. Culbertson Dr. J. D. Bradley * , Visiting Scientist, Medtronic Corporation Shawn Whaley * & Qian Bradley * , graduate students David Sell* & Murdock Hart, undergraduate Res. Assist, COLLABORATORS Dr. Clive Sell * , MD, vitro-retineal surgeon Dr. Mark Kwong, Chem. Eng., MD, ophtamological surgeon John Mitchell *, Comp. Eng., MBA, CEO Clarizza Watson *, Chem. Eng., MBA, Marketing + Funded by Royalties from US patent 6,613,677 AZ ABOR Tech ASU Strategic Initiative Fund Emeritus College Grant , Bausch & Lomb Donation Associated Retina Consultance. LLC * SiO2 Associates, Founders & Members

FACULTY AND STUDENTS + Department of Physics, ASU Prof. Nicole Herbots*, emeritus Prof. R.J. Culbertson Dr. J. D. Bradley*, Visiting Scientist, Medtronic Corp. Shawn Whaley* & Qian Bradley*, graduate students David Sell* &Murdock Hart, undergr. Res. Assist, Maggie Mitchell, Administrative Assistant

COLLABORATORS Dr. Clive Sell * , MD, vitro-retineal surgeon Dr. Mark Kwong, Chem. Eng., MD, ophtamological surgeon John Mitchell *, Comp. Eng., MBA, CEO Clarizza Watson *, Chem. Eng., MBA, Marketing + Funded by Royalties from US patent 6,613,677 AZ ABOR Tech ASU Strategic Initiative Fund Emeritus College Grant , Bausch & Lomb Donation Associated Retina Consultance. LLC * SiO2 Associates, Founders & Members

Expertise CONTROL OF SI SURFACES AT THE ATOMIC SCALE Creation of highly planar ordered surfaces Control of surface electrical properties Control of hydro-affinity of surfaces Creation of hermetic seals by direct atomic bonding

Motivation BIOMEDICAL ENGINEERING 1. Cure Medical Complications From Cataracts stop condensation on hydrophobic lenses during surgery How to inhibit condensation on a surface? 2 . Create Implantable Medical Sensor e.g. an Artificial Pancreas bond hermetically silica into an implantable glucose monitor How to connect two silica surfaces as if they were one? SCIENTIFIC understanding surface condensation , hydroaffinity (attraction to water) …. And .... bonding at the nanoscale How do water molecules interact with Si, SiO 2 , Silicone, acrylics …. Polymers … any material ..

Outline 1. SCIENTIFIC MODELS & Discoveries • 3-D String, RasMol, patents on Si(100) & SiO 2 • hydrophobic/hydrophilic surfaces of Si(100) & SiO 2 2. EXPERIMENTAL PROCEDURES: Laboratories clean-room, wet chemical laminar hoods • synthesis, contact angle, bonding & condensation on Si(100) crystal, SiO 2 , silicone, acrylic lenses, etc… topography by Atomic Force Microscopy (AFM) composition by Ion Beam Analysis (RBS, PIXE) 3. RESULTS: 4 ASU Patents, two of which filed on 4/09 and 11/09 • “ Wafer bonding using a nanophase connecting both surfaces” • “ Inhibition of condensation on surfaces ..” (Inter Occular Lenses)

Nanoscience, materials physics, biophysics, artificial eye-lens & pancreas? Artificial Eyelens Bio-Medical Challenge : Modify the surface of a silicone lenticular implant so it does NOT “fog” during surgery Artificial Pancreas Bio-Medical Challenge BOND a blood chemistry monitor (typically on quartz) directly to a single implantable device mounted on silicon wafers. • PHYSICS: Greatest Feat of 20 th Cent. “Contemporary Physics” Unification of Physics & Chemistry [Slater, Feyman] Greatest Feat of the 21 st Century “ New Physics ” : Unification of Physics with Biology?

SCIENTIFIC MODELS: Understanding surface condensation , hydroaffinity, bonding at the nanoscale … How do water molecules interact with surfaces? hydrophilic hydrophobic Water molecules are electrical dipoles

How do water molecules interact with each other or with surfaces? hydrophilic hydrophobic Water molecules interact with each other as electrical dipoles Water dipoles interact with FREE charges, defects, ions

Medical MOTIVATION #1 How important is this problem? ] Vision at age 40 1 in 5 will develop cataracts 20M Americans have cataracts Cataracts are the leading cause of blindness in the world World Health Organization Everyone will develop cataracts One Cure – Cataract Surgery After Cataract Surgery Most Crystalens Patients Studied 20/40 or Better Bausch & Lomb Early Life Vision Vision at age 65+ 50% cataract rate National Health Institute

Medical MOTIVATION #1 How important is cataract surgery? Most common surgery in the world 15 million cataract surgeries performed each year

Motivation – access for all by removing problem STOP condensation on hydrophobic IOL during secondary surgery, after cataract surgery LET’s SOLVE THIS PROBLEM!

SCIENTIFIC MOTIVATION understanding surface condensation , hydroaffinity …. And .... bonding at the nanoscale What is “nanoscale “? Interspacing between atoms in a silicon crystal or Si(100) surface = 2.5 nm hermetically bond a blood chemistry sensor to a processor = “ Nanobonding” with with an interphase “ Dangling” bonds Quartz Si (100) BEFORE AFTER Quartz Si (100)

x y SCIENTIFIC MOTIVATION understanding surface condensation , hydroaffinity (attraction to water) …. And .... bonding at the nanoscale What is “nanoscale “, how do water molecules interact ? SiO 2

Ordered Oxide Patent, licensed to Intel Foundational Patent covers Herbots-Atluri clean Ordered nanophases such as ORDERED Si(100) hydroxyl terminated surface, results in hydrophobic behavior Passivated Si(100) Surface OH OH OH OH

3. EXPERIMENTAL PROCEDURES: Laboratory : No sodium, CLASS 100 clean-room, hoods • synthesis, contact angle, bonding & condensation on Si(100) crystal, SiO 2 , silicone & acrylic lenses, - Atomic Force Microscopy (AFM) - surface composition by ion scattering (RBS, PIXE)

• Chemical Fume and Laminar Flow Hoods OUTSIDE THE CLEAN ROOM FOR • experiments on silicone & acrylic IOL’s Use SALINE and Deionized (DI) Water (2 MegOhms, 18 MegOhms)

Hydrophobic Acrylic IOL’s T = 38 °C All 4 IOL’s FOG Within 5 s

How do water molecules interact with each other or with surfaces? Model System , clean-room • contact angle Silicon surface Si(100) Hydrophilic Silicon Hydrophilic Silicon Demonstration of passivated, terminated, ordered Si(100) regions Next to a defect rich Si(100) region Using metered water drops for contact angle measurements to qualify (1) hydrophobic and (2) hydrophilic behaviors

EXPERIMENT: MEASUREMENT OF CONTACT ANGLES Direct Observation of silicone & acrylic lenses Silicone Lens Acrylic Lens

EXPERIMENT: silicone & acrylic lenses’ surface topography by Atomic Force Microscopy (AFM) Silicone surface is very smooth (Optically Superior) Acrylic surface is rougher

Immediate FOGGING Observed on BOTH Silicone & Hydrophobic Acrylic IOL’s NO Fogging After VitreOx on BOTH Silicone & Hydrophobic Acrylic IOL’s T = 38 °C Hydrophobic Acrylic IOL’s

Hydrophobic Acrylic IOL’s T = 38 °C After VitreOx TM Identical treatment for two different materials!

4. RESULTS: Two ASU Patents “Inhibition of condensation on surfaces ..” (Inter Occular Lenses (IOL’s, etc..) Dr. Clive Sell, MD smiles as he applies our bio-compatible treatment, “VITREOX” to render an IOL hydrophilic. He has used the technique successfully

What might an artificial pancreas look like? create an artificial pancreas = integrate (1) blood glucose sensor + (2) monitoring electronics hermetically into a single implantable device How to connect two silica surfaces as if they were one?

The goal is to avoid painful “finger pricks” and CONTINUOUSLY monitor blood chemistry http://www.medtronic-diabetes.com.au/images/launch/diagram_02.jpg create an artificial pancreas = integrate (1) blood glucose sensor + (2) monitoring electronics hermetically into a single implant device How to connect two silica surfaces as if they were one?

The implanted monitor sends radio-waves to the insulin pump processor to activate the alarm (“ eat ”) or deliver insulin (“ fast ”)

Practically, it boils down to BOND ING: a“Quartz” Wafer with bio-sensors on it TO a Silicon Wafer supporting both microprocessor and a radio emitter which means BONDING a wafer of Silicon Oxide , SiO 2 (= glass) to a Silicon wafer called Si(100) because of its “facet” => We are really researching Direct Nanobonding Between Si(100) and SiO 2 *

Exploring Nano-Bonding of silicates and Si(100) wafers & dices Goal – Direct Hermetic * bond between Si(100) and SiO 2 surfaces Experimental Design Wet Chemical Processing Clamping Annealing to induce bonding Observation & Results * Hermetic means NO LEAKING, NO CORROSION IN THE HUMAN BODY/SALINE SOLUTION !

Let’s “NANO-bond!” = bond at the atomic scale, along crystal “facets” of the silicon crystal Silicon Wafer Quartz Wafer Silicon Wafer Quartz Wafer BEFORE AFTER

SCIENTIFIC MOTIVATION: Understanding surface condensation , hydroaffinity, bonding at the nanoscale … How do water molecules interact with Si, SiO 2 ? SiO 2 surfaces are very stable, hydrophobic Etching creates dangling bonds on the SiO 2 surface, renders hydrophilic Si(100) is initially hydrophilic , very reactive Our 6,613,677 patent passivates Si(100) with OH termination & renders it hydrophobic

Wet Chemical Processing Wet chemical processing (1) passivate or (2) make Si(100) and SiO 2 surfaces more reactive. Herbots-Atluri process passivates Si(100) with OH-like groups (see ABOR US patent 6.616,677 (9/3/03) Explore wet chemical processing to nucleate & grow nanophases across Si(100) /SiO 2 interfaces Passivated Si(100) Surface OH OH Reactive Surface OH OH

Wet Chemical Processing of Si(100) (1) Initial Native Oxide (2) Hydrocarbon removal (3) Aqueous HF etch (4) Chemical oxide and planarization (5) Oxide strip (6) Silanol (OH) termination Passivated but ready to react 18 MegOhms Deionized (DI) Water rinse between each step for 10 minutes

Polarization Properties Contact Area Doubled in Size with NO Applied pressure Polarization Due to Oxygen Deficient Oxide Mixed Cleans Used to Maximize Effect

Why Clamping? Surface Roughness 0.2 nm r.m.s Terrace length > 20 nm Warp A+B < 30 microns Thickness Variation A+B < 25 microns Herbots-Atluri clean smoothens surface from 2 nm to 20 nm terraces Clamped Surface

Motivation Scientific background Understanding of Si and SiO 2 surfaces structure & properties Silicon surface After cleaning and passivation (inhibit further oxidation), dangling bonds are terminated resulting in hydrophobic behavior if the surface is “ordered” Defects on the surface may act like nucleation sites for water condensation Silicon with SiO 2 thin layer Alter surface from hydrophobic to hydrophilic using Herbots-Aturi clean, then grow a SiO 2 thin layer Demonstration of passivated, terminated, ordered Si(100) regions Next to a defect rich Si(100) region Using metered water drops for contact angle measurements to qualify (1) hydrophobic and (2) hydrophilic behaviors

Motivation Scientific background Model Deposition of Si and O on a Si(100) substrate creates an SiO 2 thin layer Silicon oxide reactive surface results in the hydrophilic behavior x y

Outer Shell electrons (symbolized by ) Configuration available for bonding, defect (symbol for missing electron for a complete shell ) Building a Silicone Molecule Carbon has polymorphic phases, flexibility in bonds - + Oxygen Silicon Carbon Hydrogen More directional, single phase, only one kind of rigid bonding Strongly electronegative in the outer shell With 6 negatively charged electrons - Hydrogen is a strong electron donor

2) Oxygen-Silicon-Oxygen-Silicon- Oxygen Atom Chain Method Model Silicone structure: SiO(CH 3 ) 2 is the building block (monomer) 1) First chemical building block Si-O atom pair 3) Si-O atom pair with electron configuration and bonding sites (a) Before bonding (b) After bonding 4) Backbone of the silicone chain Si-O-Si-O-Si-O-Si-O. showing the sites Available for bonding CH 3

Method Model A Si-O chain with a CH 3 radical attached, the radical can rotate in the plane Defects and mobile charges Polydimethylsiloxane PDMS Silicone

Fogging = nucleation of water droplets + subsequent interaction to free mobile charges on hydrophobic surface Ostwald ripening = droplets enlarges with time, small droplets combine to bigger droplets to minimize area to volume ratio & surface energy To Understand and inhibit condensation on Silicone surface

Application Emergency device during retinal surgery Procedure Fogging DISTORTION Time to Fog (s) VitreOx™ NO NO > 1200 s (20 min) + Healon® YES YES 290 s Viscoat® YES YES 10 s Wiping YES YES 5 s Natural YES YES 3 s

RESULTS ON DIFFERENT IOL’s Permanent coating on IOL devices Permanent Coating CONDENSATION DISTORSION Time to Time to Fog (seconds) Silicone IOL Preserved in air NO NO 1200 seconds + = 20 minutes + Silicone IOL Preserved in saline NO NO Ongoing Trials Hydrophobic acrylic IOL Preserved in saline NO NO Ongoing Trials

Surface Engineering Research for Bio-Medical & Medical Electronics Applications in 2010: NanoBonding™ and VitreOX™

More Related Content

Similar to Surface Engineering Research for Bio-Medical & Medical Electronics Applications in 2010: NanoBonding™ and VitreOX™ (20)

Recently uploaded (20)

Surface Engineering Research for Bio-Medical & Medical Electronics Applications in 2010: NanoBonding™ and VitreOX™

Editor's Notes