Bi7430 Molecular Biotechnology
7. Microfluidics – „Lab on a Chip“
Outline
 Introduction to microfluidics
 Physics of micro-scale
 Design and fabrication
 Sensing and detection
 Lab on a chip (LOC) concept
 Examples of LOC applications
Introduction to microfluidics
 d e v e l o p e d i n t h e 1 9 8 0 s ( I B M )
 m u l t i d i s c i p l i n a r y f i e l d
e n g i n e e r i n g , p h y s i c s , c h e m i s t r y,
m a t e r i a l s c i e n c e , n a n o t e c h n o l o g y
 i n t e g ra t e p r o c e s s e s o n c h i p
 m i n i a t u r i z a t i o n a n d a u t o m a t i o n
 ( u l t r a ) f a s t t h r o u g h p u t
 h i g h p r e c i s i o n
 l o w e n e r g y a n d s a m p l e c o n s u m p t i o n
 l e s s w a s t e p r o d u c t i o n
 c o n t i n u o u s - f l o w m i c ro f l u i d i c s
m a n i p u l a t i o n o f c o n t i n u o u s l i q u i d f l o w
t h ro u g h m i c ro - fa b r i c a t e d c h a n n e l s
 d ro p l e t - b a s e d m i c ro f l u i d i c s
m a n i p u l a t i n g d i s c re t e v o l u m e s o f f l u i d s
i n i m m i s c i b l e p h a s e s
 d i g i t a l m i c r o f l u i d i c s
d ro p l e t s m a n i p u l a t e d o n a s u b s t ra t e
u s i n g e l e c t ro - w e t t i n g
Introduction to microfluidics
Physics of micro-scale
 m i c r o d o m a i n d i f fe rs g re a t l y f ro m m a c ro s c o p i c f l u i d s
 s m a l l v o l u m e s ( n L , p L , f L )
 r e d u c e d i m e n s i o n s ( m m , m m )
 l a r g e s u r f a c e a r e a - t o - v o l u m e r a t i o
 h i g h l y e f f i c i e n t m a s s a n d h e a t t r a n s f e r
Physics of micro-scale
 s u r fa c e t e n s i o n
 s t r e t c h f o r c e a l o n g t h e m a t e r i a l i n t e r f a c e
 C a p i l l a r y n u m b e r ( C a ) r a t i o b e t w e e n
v i s c o u s f o r c e t o s u r f a c e t e n s i o n
 C a < < 1 i n m i c r o f l u i d i c s , f l u i d d o m i n a t e d
b y s u r f a c e t e n s i o n
 w e t t i n g o n ( h y d r o p h i l i c ) s u r f a c e s
 e l e c t r o w e t t i n g - e l e c t r i c a l m o d u l a t i o n
o f t h e s o l i d - l i q u i d s u r f a c e t e n s i o n
Physics of micro-scale
 v i s c o s i t y
 R e y n o l d s n u m b e r ( R e ) r a t i o b e t w e e n
i n e r t i a l f o r c e t o v i s c o u s f o r c e
 R e < 1 i n m i c r o - f l u i d i c s , f l u i d s i n f l u e n c e d
b y v i s c o s i t y r a t h e r t h a n i n e r t i a
 l a m i n a r f l o w a n d d i f f u s i o n d o m i n a n t
 m i x i n g i n m i c r o s c a l e c h a l l e n g i n g
Design and fabrication
 d e s i g n
 e n g i n e e r i n g s o f t w a r e s ( e . g . , A u t o C A D , D r a f t S i g h t )
 m o d e l l i n g ( e . g . , C O M S O L , M a t L a b )
 p r i n t i n g t h e m a s k
Design and fabrication
 fa b r i c a t i o n
 s o f t p h o t o l i t h o g r a p h y
 n e g a t i v e / p o s i t i v e p h o t o r e s i s t s
 P D M S m o l d i n g
Design and fabrication
 fa b r i c a t i o n
 d i r e c t f a b r i c a t i o n m e t h o d s
o 3 D p r i n t i n g
o C N C m i c r o - m i l l i n g
o l a s e r c u t t i n g
Design and fabrication
 m a t e r i a l s
 i n e r t a n d t r a n s p a r e n t
 P D M S - p o l y ( d i m e t h y l s i l o x a n e )
 P M M A - p o l y ( m e t h y l m e t h a c r y l a t e )
 f u s e d s i l i c a , q u a r t z a n d g l a s s
 s u r fa c e m o d i f i c a t i o n
 p l a s m a t r e a t m e n t
 s i l a n i z a t i o n
 f u n c t i o n a l i z a t i o n
 s o l – g e l c o a t i n g
Sensing and detection
 p ro c e s s i n g o f s m a l l re a g e n t v o l u m e s
 a n a l y t i c a l t i m e s c a l e a n d p e r fo r m a n c e
 o n c h i p d e t e c t i o n
 f l u o r e s c e n c e
 U V/ V I S a b s o r b a n c e
 I R s p e c t r o s c o p y
 R a m a n s c a t t e r i n g
 ( c h e m o / e l e c t r o ) l u m i n e s c e n c e
 t h e r m a l c o n d u c t i v i t y
 R I v a r i a t i o n
 o f f c h i p d e t e c t i o n
 G C , H P L C , M S
 N M R , X - r a y
Microfluidics
 b e n e f i t s o f m i n i a t u r i s a t i o n
 s u p e r i o r p e r f o r m a n c e ( s p e e d , e f f i c i e n c y a n d c o n t r o l )
 r e d u c e d c o n s u m p t i o n o f s a m p l e / r e a g e n t a n d p o w e r
 c o s t e c o n o m i e s t h r o u g h m i c r o m a c h i n i n g
 p o r t a b i l i t y ( p o i n t - o f - c a r e / u s e a p p l i c a t i o n s )
 f a c i l e p r o c e s s i n t e g r a t i o n a n d a u t o m a t i o n
 h i g h a n a l y t i c a l t h r o u g h p u t
Lab on a Chip (LOC) concept
o n a c h i p i n t e g ra t i o n o f l a b o ra t o r y p ro c e s s e s
P r e p a r a t i o n
A n a l y s i sI n c u b a t i o n
C o l l e c t i o n
P r e - t r e a t m e n t
Life science and medical application
 a n a l y t i c s a n d sy n t h e s i s
 P C R a n d s e q u e n c i n g
 d i a g n o s t i c s
 p h a r m a c o l o g y
 p ro te o m i c s
 ( u l t ra ) h i g h - t h ro u g h p u t b i o l o g y
 c l i n i c a l s t u d i e s
Organs (human) on chip
N e u r o v a s c u l a r
I n t e s t i n e
L u n g
K i d n e y
S p l e e n
H e a r t
B o n e
A r t e r y
Organs (human) on chip
 o r ga n s - o n - a - c h i p
 m u l t i - c o m p a r t m e n t a l 3 D m i c r o f l u i d i c c e l l c u l t u r e c h i p s
 s i m u l a t e s a c t i v i t i e s , m e c h a n i c s a n d p h y s i o l o g i c a l r e s p o n s e
 r e a l i s t i c i n v i t r o m o d e l c l o s e r t o i n v i v o c e l l e n v i r o n m e n t
 m i m i c k i n g h u m a n ’s p h y s i o l o g i c a l r e s p o n s e s
( e . g . , p a t h o l o g i c a l r e s p o n s e s , p h a r m a c o k i n e t i c , t o x i c o l o g y )
 h u m a n - o n - a - c h i p
 i n t e r a c t i o n s u n d e r n e a r - p h y s i o l o g i c a l f l u i d f l o w c o n d i t i o n s
 s i m u l a t i n g m u l t i - o r g a n m e t a b o l i c i n t e r a c t i o n s
 s y n e r g i s t i c d r u g i n t e r a c t i o n s
 c a n re p l a c e e x p e n s i v e a n d c o n t ro v e rs i a l a n i m a l t e s t i n g
(Ultra)High-throughput biology
(Ultra)High-throughput biology
S T A N D A R D D E S I G N
 r a n d o m m u t a g e n e s i s ( 2 - 3 p o s i t i o n s )
 l i b r a r y o f 1 0 4 c l o n e s
A D V A N C E D D E S I G N
 r a n d o m m u t a g e n e s i s ( 5 - 7 p o s i t i o n s )
 l i b r a r y o f > 1 0 6 c l o n e s
v o l u m e : 1 0 ´ p L
a s s a y s / d a y : 1 0 7
v o l u m e : 1 0 0 ´ m L
a s s a y s / d a y : 1 0 3
(Ultra)High-throughput biology
 m o n o d i s p e r s e e m u l s i o n ( 2 p L , 1 0 7 d r o p l e t s / h o u r )
 f l u o r e s c e n c e - a c t i v a t e d o n - c h i p d r o p l e t s o r t i n g ( FA D S )
 1 0 3 e v e n t s / h o u r
Baret et al. 2009. Lab Chip 9: 1850-1858 Abate et al. 2010. Appl. Phys. Lett. 96: 203509
(Ultra)High-throughput biology
 f l u o r e s c e n c e - a c t i v a t e d o f f - c h i p c e l l s o r t i n g ( FA C S )
 1 0 8 e v e n t s / h o u r
 m o n o d i s p e r s e d o u b l e e m u l s i o n ( 2 p L , 1 0 7 d r o p l e t s / h o u r )
Polymerase chain reaction
 c l a s i c a l P C R
 9 6 - w e l l m i c r o - t i t r e p l a t e s
 v o l u m e 5 0 t o 5 0 0 m L
 s l o w h e a t i n g / c o o l i n g c y c l e s
K a r y M u l l i s
N o b e l P r i z e i n 1 9 9 3
Polymerase chain reaction
 P C R i n m i c r o f l u i d i c d r o p l e t s
 5 0 0 d r o p l e t s p e r s e c o n d
 v o l u m e 5 0 t o 1 0 0 p L
 2 9 s p e r h e a t i n g / c o o l i n g c y c l e
Schaerli et al. 2009. Anal. Chem. 2009, 81, 302–306Kiss et al. 2008. Anal. Chem. 80, 8975–8981
Digital PCR
 “ Q X 1 0 0 ” D r o p l e t D i g i t a l P C R ( B i o R a d )
 “ R a i n d r o p ” D i g i t a l P C R ( R a i n d a n c e )
Next-generation sequencing
 p a ra l l e l i z a t i o n o f s i n g l e m o l e c u l e s e q u e n c i n g
 4 5 4 P y r o s e q u e n c i n g ( Ro c h e )
d e t e c t i o n v o l u m e 1 p i c o l i t e r ( 1 0 - 1 2 l i t re s )
1 m i l . re a d s p e r r u n , 1 0 U S D p e r M b a s e
F r e d e r i c k S a n g e r
N o b e l P r i z e i n 1 9 8 0
Next-generation sequencing
 p a ra l l e l i z a t i o n o f s i n g l e m o l e c u l e s e q u e n c i n g
 S M R T s e q u e n c i n g ( Pa c i f i c B i o s c i e n c e s )
d e t e c t i o n v o l u m e 2 0 ze p t o l i t e rs ( 1 0 - 2 1 l i t re s )
0 . 1 m i l . re a d s p e r r u n , 0 . 5 U S D p e r M b a s e
Next-generation sequencing
 H u m a n G e n o m P ro j e c t - 1 0 y e a rs , 3 b i l l i o n U S D
 g e n o m e s e q u e n c i n g t o d ay i n 1 0 t o 1 5 h rs
Plants on a chip
Grossmann, G., et al. 2011. The plant cell online, 23 (12), 4234-4240
 e f f i c i e n t c o n t ro l o v e r s e v e ra l s i m u l t a n e o u s ex p e r i m e n t s
 o b s e r v e d e v e l o p i n g ro o t s i n p a ra l l e l
 f l u o re s c e - l a b e l e d m e t a b o l i t e a c t i v i t y
 i n te ra c t i o n w i t h sy m b i o n t s / p a ra s i te s