FIELD OF INVENTION
The present invention relates to a surface functionalization unitldevice useful for
functionalization of a substrate. More particularly the present invention relates to an integrated
dual chamber compact unitldevice which can perform multiple function(s) of cleaning, rinsing,
hydrolyzing, drying, silanization, crosslinking of a substrate in a controlled environment.
BACKGROUND OF THE INVENTION
Surface functionalization is an important aspect of surface preparation of substrates with
different functional n~olecules to conduct many analytical techniques in applied chemistry,
biology etc. It is the act of modifying the surface of a material by bringing physical, chemical or
biological characteristics different from the ones originally found on the surface of a material.
The method(s) being used for performing surface functionalization of a substrate con~prises
different set of sequential processes. For example, the typical process steps involved in
preparation of a substrate surface for inlmunosensing application consists of a) substrate cutting,
b) substrate cleaning, c) hydrolysis, d) silanization. e) crosslinking, and finally f) attachment of
biomolecules.Currently these process steps have been practiced majorly by manual means using
beaker chemistry. Though there are some instruments available to carry out one or two
individual process steps, their use is limited due to several problems associated in processing
different samples as will be mentioned in the subsequent paragraphs. The most important aspect
to be considered in the process of surface functionalization is the time gap between the process
steps, avoiding manual intervention in handlingltransferring the samples, controlled environment
and preparing all samples at one go in a single instrument to get reliable samples.
The existing device and methods in the prior art suffers from the problems of:
(i) Different processes in different set-ups affect reliability issues due to a sample
exposure during steps.
(ii) Also, handling small substrate sizes in the conventional processes have handling
issues affecting quality.
(iii) The process time is longer.
C (iv) Do not provide the sample cleaning either by wet or dry methods
(v) Do not provide the sample hydrolysis by wet and dry methods
(vi) Do not provide the facility to use air (hotlcold), Nitrogen, water (liquidlvapor),
and organic liquid sprays (e.g. ethanol) etc during substrate fui~ctionalization.
(vii) Do not provide the ease of handling samples from beginning of the sample
preparation to end of the process without need to touch or remove from the
vacuum disc. (i.e. in existing systems the samples need to be removed and kept
on to the substrate holders several times during processing).
(viii) Do not provide the sample rinsing by jetting or spraying the suitable solution
with required pressure.
(ix) Do not provide the facility to use same resources such as liquid
co~~nections/tubes/porftso r similar liquids and gas connections/tubes/ports for
gases during the functionalization process.
(x) Do not provide the controlled environment (i.e. providing the inner atmosphere
of the instrument either of Nitrogen or any other inert gas based).
(xi) Do not provide the freedom to adjust the distance between the sample and the
coating liquidlreservoir, which hinders the process optimization when used for
other protocols/chemicals to deposit.
(xii) Since the deposited materials are of atomic layer thickness and sensitive, the
properties of the deposited films changes due to the time taken to transfer the
samples between process steps from one instrument to other.
(xiii) And exposure of the samples to atmospheric conditionsalters the properties and
hence poor reliability of the samples.
(xiv) Using different instruments for different process steps of surface
functioilalizatioi~ requires more resources, increased the foot print area.
operational complexity and high cost.
Thus, a single device which can perform multiple step(s) of functionalization process to prepare
thesubstrate is highly desirable.
US6699527 teaches a process for the surface functionalization of a polyn~eric substrate, which
process comprises: a) contacting the substrate with a diarylcarbene precursor, b) generating a
carbene reactive intermediate from the diarylcarbene precursor so that it reacts with the substrate
to functionalize the surface, and c) further functionalizing the activated substrate obtained in step
(b).
W01983002669 teaches a silanization technique, which combines a special cleaning technique
for the surfaces to be silanized with a silanization process at a low pressure and with the silane in
gas phase and at an enhanced temperature of the surfaces to be silanized. The method gives
reproducible surfaces provided with stable, homogeneous and functional silane layers of
monolayer character. Said surfaces are then used for covalent coupling of highly specific organic
n~oleculesa nd biomolecules to the surfaces.
US 6444268 teach that a low surface energy functionalized surfaces on solid supports are
provided by treating a solid support having hydrophilic illoieties on its surface with a
derivatizing con~position containing a mixture of silanes. A first silane provides the desired
reduction in surface energy, while the second silane enables functionalization with molecular
moieties of interest, such as small molecules, initial monomers to be used in the solid phase
synthesis of oligomers, or intact oligomers. Molecular moieties of interest may be attached
through cleavable sites. Derivatizing coinpositions for carrying out the surface functionalization
process are provided as well.
US 20130022752 teaches a method for treating the surface of a substrate may include forming
radicals on the surface of the substrate by exposing the surface to a first atmospheric plasma
formed from a first process gas comprising an inert gas to break chemical bonds on the surface,
wherein a first portion of the radicals fonn reactive sites on the surface and a second portion of
c r a d i c a l s form
first atmospheric
protective sites on the surface; functionalizing the reactive sites formed by the
plasma by exposing the surface of the substrate to a second atn~osphericp lasma
formed from a second process gas comprising the inert gas and water vapor (H20): and forming
a layer on the functionalized surface of the substrate by exposiilg the surface of the substrate to a
layer fornling species during or after exposure to the second atmospheric plasma.
US 20140046076 relates to a process that is useful for surface functionalization of a substrate
conlprising at least one hydroxyl function, in which one or more point regions of said surface are
brought into contact with an ionic liquid matrix containing at least one reactive molecule, as it is
known, that carries at least one reactive function, under conditions that are suitable for the
creation of a covalent bond between said reactive function of the molecule and a hydroxyl
function of said surface.
The abovementioned processes have to be performed by using different set of device(s) and
therefore are not found to be efficient in terms of reliability issues, handling issues and quality
issues.
Therefore, there is an existing need of an integrated coinpact surface functionalization device
which can perform multiple steps of cleaning, rinsing, hydrolysing or drying of a substrate along
with fui~ctionalizationo f a substrate including silanization, crosslinking etc.
OBJECTIVE OF THE INVENTION
Primary objective of the present invention is to overcome the drawbacks of the prior art.
Another objective of the present invention is to provide a con~pact device for
surfacefunctionalization of substrate in a controlled environment comprising dual cllan~bers.
Yet another objective of the present invention is to provide an integrated con~pact surface
functionalization device which can perform multiple steps of cleaning, rinsing, hydrolysing or
drying of a substrate along with functionalization of a substrate including silanization,
crosslinking etc.
Yet another objective of the present invention is to provide an integrated compact surface useful
for functionalization of a substrate with the size of as less as 5mm x 5mm.
the process handling time,
provide a device for surface functionalization of substrate ~vhichs aves
reducing complexity of operating different units.
Yet another objective is to provide a device for surface functionalization of substrate which
provides facility to operate the whole unit at single envirolment or each Chamber at different
atmosphere.
Yet another objective is to provide a device for surface functionalization of substrate which
provides provision for hot or cold aidwater or vapor supply to the unit by inbuilt heating system.
Yet another objective is to provide a device for surface functionalization of substrate which
provides provision for the utilities (such as gases, liquids) with required flow rate at desired
pressure.
Yet another objective is to provide a device for surface functionalization of substrate which
provides provision for the facility to adjust the distance between the samples and the crucible to
make the unit suitable for different process protocols.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1 illustrates the surface functionalization unit, comprising two chambers, with all the
components.
Figure 2 illustrates the Sample holding disc assembly.
Figure 3 illustrates the sample holding disc.
Figure 4 illustrates n~otor's regulator circuit box; 4(a) shows motor's regulator circuit setup; 4
(b) illustrates motor with vacuum provision; 4(c) illustrates spinner motor operation with power
controller; 4(d) illustrates surface functionalization.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention provides a surface functionalization unit, comprising two chambers, where
functionalization is conducted in a unit that overcomes the above mentioned problems and
provides reliable preparation of the substrates with lot more convenience. This unit completely
replaces the problems and difficulties in methods currently under practice i.e. sample preparation
either by using different instruments or by using typical wet bench processes etc.The device of
lgpresent Invention offers in-house treatment of the samples in controlled environment. There
-
are dedicated units available for surface silanization in vapor phase, however carrying out
complete surface functionalization of the substrates (inorganic and organic) from cleaning to
crosslinker stage in wetldry form by spinning the substrates at required rotation to deposit
uniform layers including rinsing and drying steps in a single compact unit in a controlled
environment makes the device of the present Invention effective.
The unitldevice of the present Invention is particularly designed in accordance to the processes
being used in the preparation of substrate surface for illlrnunosensing applications. The present
invention provides a surface functionalization facility in a11 integrated compact unit instead of
separate units for performing different operation(s). Further, the present unit enables large scale
processing of samples of sizes as small as 5 mm x 5 mm, which can be used in commercial
ELISA wells to carryout biological assays. The device performs all the functions efficiently and
prepares highly reliable functionalized samples and more importantly, the usage of the
instrument can be generalized for any application which involves the preparation of
functionalized substrate surfaces just by choosing desired process protocols as per requirement.
The present invention provides a compact unitldevice for surfacefunctionalization of substrate in
a controlled environment, where complete surface functionalization of the substrates (inorganic
and organic) from cleaning to crosslinker stage in wetldry form and by spinning the substrates at
required rotation to deposit unifom~ layers including rinsing steps is done in a single con~pact
unit.
In one aspect, the present invention relates to dual chamber surface functionalization unit for
carrying out wetldry cleaning along with vapor phase deposition of different functional
molecules. The device is useful for functionalisation of the substrate having as small as 5 mm x 5
mm size and to any required dimensions. .
The said dual chamber surface functionalization unit comprising of
1 . Chamber 1 including:
i. Teflon disc (1);
ii. Vacuum(2);
iii. DC motor(3):
iv. Coillpressed air supply(CDA)(4):
v. Hot water spray(5);
vi. Nitogen gas spray(6);
vii. Oxygen spray(7);
viii. UV light(8);
ix. Ethanol spray(] 4).
x. VentIPurge lines (1 5)
2. Chamber 2 including:
i. Motor shaft (9);
ii. Vacuum (9A)
iii. Crucible(] 0);
iv. Heating base (1 1);
v. Vacuum line (12);
vi. Valve (1 3);
vii. Movable stage (1 6);
viii. VentIPurge lines (1 7);
ix. Level adjuster (1 8).
In addition, the detailed information of the individual parts of the surface functionalization unit is
provided below.
3. Sample holding disc assembly
i. Motor (19)
. .
11. Outer disc for vacuum sealing (20)
iii. Inner rotating disc (21)
iv. Holes to hold the samples (22)
4. Saillple holding disc
i. Vacuum blind cap(23)
ii. Sample (24)
iii. Ports for vacuum (25)
iv. Upper disc (26)
v. 0- ring (27)
vi. Circular cavity for 0 ring (28)
vii. Hole for vacuum (29)
viii. Lower disc (30)
ix. Valve for controlling vacuum (3 1)
x. Connector to fix on the motor shaft (32)
In another aspect, the present invention relates to a process of functionalization of substrate using
the said surface functionalization unit. The said chamber 1 includes a removable Teflon disc
(l)(Figure 3) having small pin holes to hold the substrates by using vacuum (2) and is held on to
C h a f t of a DC motor (3) which rotates at required rpm (60 to 4000 rpm) and continuouslg spin
for maximum of 10 hours.
Further, in the spin chamber there is a provision for conlpressed air (herein after referred to as
CDA) supply (4) which passes through the heating chamber fixed at the backside of the unit
provided with a comn~ercially available PID temperature controller. Initially this CDA can be
used to flush out any particulate contamination from the substrates surface, held to the Teflon
disc with vacuum while it is spinning. Hot water (5) sprayed on to the substrates and spinned for
required time to dry the substrates while spraying Nitrogen gas (6). The chamber is thereafter
filled with the oxygen (7) and UV light (8) is switched on for specified time (from 20 seconds to
1 hr), which creates the hydroxyl bonds on to the substrate and this step completes the dry
hydrolysis process.
The Teflon disc(1) (Figure 3) containing the sanlples with vacuum tightened within the disc is
thereafter removed from the chamber 1 and is transferred to the chamber 2 and locked on to the
motor shaft (9) and before releasing the vacuum of the Teflon disc, vacuum (9A) pump is
switched on and vacuum valve of the disc turned on and off to create the continuous vacuum in
the disc.
The specific process involves hydrolysis, silanization, wherein the disc along with motor is
turned downward and placed on to the vacuum chamber and gasket present between the chamber
and disc creates airtight seal. Prior to this the saline solution is poured into the crucible (10)
which is kept on a heating base (1 1) and set the require temperature (0 to 150°C) in the control
panel fixed infront side of the unit. Now the vacuum is created (-760 mmHg) within the chamber
using a vacuum line (12) and after reaching required vacuum the valve (13) is closed. The valves
could be operated either manually or by automatic means.The disc spins with the rotation of the
motor with the rotational speed controlled by the motor (based on the rating) and the evaporated
saline is thereafter uniforn~lyc oated on to the substrates for required time.
The chamber is purged with nitrogen(] 7)and the Teflon disc transferred to the chamber 1 where
it isrinsed by spraying ethanol (14) while it is spinning at high rpm followed by nitrogen drying.
& said samples are thereafter hot baked by spraying the hot air for specified time. This
completes the silanization process. further to create the crosslinker the same disc mould then be
transferred to the chamber 2 and required crosslinker will be heated and coated on the substrates
by following the similar steps during silanization.
The present invention has utility for fuctionalization of any type of n~olecules and the same can
be coated by vaporizing the suitable solution in the crucible for required time will results in the
uniform deposition of the functional layers.Wet hydrolysis is carried out by pouring the required
solution (piranha solution) into the crucible and heated to 130°C. The vapors generated during
this process creates the hydroxyl bonds on the substrates. this pirnaha wet cleaning can be used
for inorganic substrates.
In an embodiment of the Invention, the device cleans the substrates by a) blowing pressurized
airmitrogento remove the particulate contamination, b) using hotlcold water or water vapor to
clean and rinse the substrates followed by drying by spinning the disc at high rotational speed by
again blowing airmitrogen.
In another embodiment of the Invention, the device cleans the organic contaminated substrates
by treating with chemical vapors in the vaporization chamber at desired temperature, for
specified time at low or high rotational speed of the sample disc.
In another embodiment of the Invention, the device comprises a provision to adjust distance
between the sample and the chemical reservoir(l8).
In another embodiment of the Invention, the device hydrolyzes the substrate either by using wet
or dry methods. For dry hydrolysis, the cleaned samples present on the disc can be rotated as per
required speed. The chamber is filled with Oxygen and thereafter the UV-lamp is turned on for
required time, which creates an ozone atmosphere thereby allowing the fornlation of hydroxyl
bonds on the substrates.
In another embodiment of the Invention, the device allows wet hydrolyze the samples in
vaporization unit by treating the substrates with suitable chemical vapors at high temperatures
with choice of parameters such as process time, rotational speed of sample disc, distance
between the sample disc and the source of chemical reservoir etc.
nothe her enlbodin~ent of the invention. the device rinse the wet hydroljzed samples in the
spinner unit by selecting the choice of process parameters such as hot waterlvapor spray. cold
water spray, airmitrogen sprayand all for specified time at desired rotational speed of sample
disc.
In another embodiment of the Invention. the device carries out vapor phase silanization of
wetldry hydrolyzed samples by selecting the suitable silane liquids and heating them to required
temperature in the vaporization chamber (Chamber 2). Chamber 2 provides the choice of
parameters to choose, such as creating required vacuum in the vaporization chamber,
temperature control, process time, rotational speed of sample disc, distance between the sample
disc and crucible and finally purging with Nitrogen after completion of process.
In another embodiment of the Invention, the device rinse the silanized sample with suitable
organic solvents such as ethanol for required time by controlling pressure of the liquid spray on
to the substrates while they spun at set speed. After this, the samples can be dried by blowing
Nitrogen.
In another embodiment of the Invention, the device crosslink the silanized samples in the
vaporization chamber by choosing the suitable chemical and heating in the crucible at required
temperature for specified time with option of carrying process either in vacuum or at normal
conditions.
In another embodiment of the Invention, the device rinse and dry, the samples in the spinner unit
(Chamber 1) with suitable organic solvent (i.e. ethanol) and Nitrogen while spinning the sample
disc at required speed.
In another embodiment of the Invention, the device provides a unique vacuum holding sample
disc to hold the substrates until the last step of the functionalization.
In another embodiment of the Invention, the device eliminates frequent manual handling or
replacement/removal of samples from substrate holder during changing the process steps.
In another embodiment of the Invention, the device reduces the footprint of the surface
functionalization unit and complete automation of the unit by robotic movement of the sample
disc from one chamber to the other.
We Claim:
1. A11 integrated compact surface funtionalization device, said unit comprising:
I. a first chamber for performing cleaning, rinsing, hydrolysing or drying of a
substrate to be functionalized, wherein said chamber comprises:
a) a removable sample holding disc assembly with plurality of pin holes to
hold a substrate by using a vacuum pump which is held on to the shaft of a
first motor
b) plurality of inlet(s) for supplying gas(s) andlor liquid(s), provision for UV
light, and vent line(s);
. .
11. a second chamber for performing functionalization including silanization,
crosslinking of said substrate with the functional group(s), said chamber
comprising:
(a) a vacuum chamber with a vacuum pump, for containing said removable
sample holding disc assembly, said chamber comprising an outer disc
for vacuum sealing, a second motor with a shaft attached with a
vacuum pump, a crucible which is positioned on a heating base, and
said heating base is attached to a movable leveler so as to adjust the
distance of crucible and disc;
(b) vent line(s).
2. The device as claimed in claim 1, wherein said motor performs continuous spinning of
said sample holding disc assembly.
t 3. The device as claimed in claim 1. ~vherein the temperature of said heating base may be
-
selected upto the range of 150°C
4. The device as claimed in claim 1, wherein said reillovable disc assembly may be
transferred from chamber 1 to chamber 2 and vice-versa for performing multiple
function(s) of cleaning, rinsing, hydrolyzing, drying, silanization, crosslinking and like.
5. The device as claimed in claim 1, wherein said crucible con~prises reagents for
performing silanization, cross linking or like.
6. The device as claimed in claim 1, wherein said sample holding disc is a Teflon disc.
7. The device as claimed in claim 1, wherein said device is useful for functionalisation of a
substrate with the size of as small as 51nm x 5mm.
8. The surface funtionalization unit as claimed in claim 1, wherein said first motor is DC
motor.
9. The surface funtionalization unit as claimed in claim 1, wherein said second motor is
stepper motor.
10. The surface funtionalization unit as claimed in claim 1, wherein said gase(s) comprises
compressed air, nitrogen gas spray, oxygen spray and like.
11. The device as claimed in claim 1, wherein said liquid comprises hot water spray, ethanol
spray and like.
12. The device as claimed in claim 1, wherein said device comprises a temperature
controller.
13.'The device as claimed in claim 1, wherein said 'removable sample holding disc
comprising:
a) an upper disc having plurality of small hole(s) for holding a sample with plurality
of port(s) for vacuum capped by plurality of vacuum blind cap(s);
b) an O-ring;
c) a lower disc having circular cavity for said O-ring and a hole for vacuum;
.C d) a val1.e for controlling vacuum in said disc;
-
e) a connector to fix on said nlotor shaft.