magarray ieee presentation...
TRANSCRIPT
“Enabling Be,er Outcomes through Be,er Diagnos7cs”
Magne&c nano-‐sensors for sensi&ve protein detec&on
Adam Seger, Ph.D. Electrical Engineer
Nanoengineered Biomedical Devices
• What does it mean? • What do we need? – A biologically relevant problem – A technology that can address that problem
• How do we get there? – Get engineers together with scien&sts
ELISA
• Enzyme Linked Immunosorbent Assay • Method established 1971 – Replaced radioimmunoassay
• Chromogenic, fluorogenic • Detect proteins, an&bodies, pep&des…
ELISA
hRp://www.epitomics.com/images/products/sandwich.jpg
Giant Magnetoresistance (GMR)
• Discovered in 1988 – Albert Fert and Peter Gruenberg
• Nobel Prize in 2007
Giant Magnetoresistance
hRp://www.nims.go.jp/apfim/GMR.html
What Happens When We Combine These Technologies?
??
We Get MagArray!
Simple, ultra-‐sensi1ve, mul1plex immunoassay system
10 mm 12 mm
MagArray System What do we mean by:
• Simple -‐ Small, portable system about the size of a &ssue box…No moving parts…No microfluidics… Basic, easy step process. • Ultra-‐sensi1ve -‐ Have been able to dis&nguish concentra&ons as low as 50 aRomolar. Depending on the target protein, typical detec&on limits are in the femtomolar / picomolar range. • Mul1plex -‐ 80 individual sensors per chip. One chip per sample. Factoring in controls and replicates, researchers typically analyze 10-‐20 proteins per chip.
Detection of Multiple Analytes, Each at 1 pg/mL in PBSS. Osterfeld and H. Yu, October-2-2008
000E+0
50E-6
100E-6
150E-6
200E-6
250E-6
300E-6
350E-6
400E-6
0 5 10 15 20 25 30 35 40Minutes
Sign
al, V
p
100:1
75:1
Biotinylated Sensors
1 pg/mL Analytes
Photo of Individually Functionalized Sensors:
Biotin / BSA
GC
SF
Biotin
Epoxy
TNF-α
IL-1α
Eotaxin
INF-γ
LFVEGF
CEA
MagArray History • Founded in 2005 by team of Stanford professors who adapted a magne&c nanopar&cle technology from the computer disk drive industry for use in medical diagnos&cs • Focus on market need to beRer detect proteins and develop biomarker panels • Basic technology development from 2007-‐2011 funded primarily by federal grants and contracts • Partnership with Aisin Seiki in 2011 • Currently located in life sciences incubator in Sunnyvale • Working with alpha customers on applica&on development
How the MagArray System Works
Sample added to chip with pre-‐func&onalized capture an&bodies
Target an&gen binds to capture an&body
Detec&on an&body binds to target an&gen
Magne&c nanopar&cle binds to detec&on an&body
Magne&c nanopar&cle generates magne&c field that induces electric current in GMR sensor
Real Time, Mul&plexed Results
Superior Sensi&vity and Dynamic Range
Compared to ELISA, the MagArray system was able to detect CEA at a much lower concentra1on and across a wider dynamic range
Flexible Assay Protocols
【Express Assay】 • < 10 minutes • Homogeneous Assay • Can be run with whole blood
【Standard Assay】 • About 1 hour • Excellent sensi&vity
Add Sample Start
Add Detec&on An&bodies
Incubate 30min
Add Magne&c Par&cles
Incubate 30min Results 2-‐5
min
Add Sample, An&bodies, Par&cles
Start Results 2-‐5 min
【Enhanced Sensi1vity】 • Best sensi&vity • Same basic process • Ideal for low abundance proteins
Add Sample Start Add Detec&on
An&bodies Incubate 4 hours
Add Magne&c Par&cles
Incubate 4 hours Results 2-‐5
min
Standard vs Express Assay Performance
Minimal Sample Volume
5 µl samples
Diluted 1:100
Ran EGFR/HE4 in Duplicate
Ran Autoan&bodies in Duplicate
Extra Vial for Repeats
Wash-‐Free Assay for Analyzing Cross Reac&vity
Add magne&c nanopar&cles, then detec&on an&bodies sequen&ally: an&-‐EGFR, an&-‐CEA, and an&-‐EpCAM
Sequen&al Addi&on of An&bodies
An1bodies can be added in a stepwise process to iden1fy and isolate cross reac1vity issues.
Advantages In addi7on to superior performance in sensi7vity, dynamic range, mul7plexibility, size, cost, etc., the following unique characteris7cs are worth highligh7ng: • Real Time Read Out – Sensors are scanned every 4 seconds, and results are displayed as they
are generated, thus allowing researchers to monitor binding as it takes place. Extremely useful for “go/no go” decisions in a fast paced environment.
• Whole Blood – Op&cal interference caused by red blood cells is not a factor for MagArray’s magne&c technology. While sensi&vity is slightly less than serum, whole blood can be used as a suitable sample type.
• Sequen1al Addi1on of An1bodies – MagArray’s open well system allows for detec&on an&bodies to be sequen&ally added at any stage during the process. Researchers can iden&fy and isolate cross reac&vity issues in mul&plex assays, as well as design assay procedures to circumvent certain cross reac&vity problems.
• No Wash -‐ MagArray sensors only detect magne&c par&cles that have bound to the analytes of interest. There is no need to wash aler the addi&on of label. This is of par&cular advantage when analyzing low affinity proteins that tend to get washed away during typical assay procedures.
• Small Sample Volume -‐ Assays can be run using as liRle as 10-‐20ul. MagArray’s system allows researchers to run mul&plex assays on minute samples from small animals such as mice or rats. It is also extremely valuable for limited human samples that cannot be readily re-‐obtained.
Notable Papers