Biosensor and a biosensing kit
A biosensor with a detection transistor of a metal-semiconductor field-effect (MESFET) type, for detecting a target substance. The detection transistor has an isolating substrate, a source electrode, a drain electrode, a first gate electrode, a channel for transmitting a drain-source current between the source electrode and the drain electrode, the channel being made of an oxide semiconductor, arranged on the isolating substrate and having the source electrode and the drain electrode arranged thereon, a sensitive substrate connected to the first gate electrode and including functionalization species for bonding the target substance, such that the first gate electrode connected with said substrate is sensitive to the target substance, and a second gate electrode arranged on the isolating substrate, physically separated from the first gate electrode by the channel, positioned opposite to the first gate electrode and aimed to modulate the drain-source current of the channel.
1 . A biosensor comprising a detection transistor and a reference transistor, both of a metal-semiconductor field-effect (MESFET) type, for detecting a target substance, wherein:
the detection transistor comprises:
an isolating substrate,
a source electrode,
a drain electrode,
a first gate electrode,
a channel for transmitting a drain-source current between the source electrode and the drain electrode, the channel being made of an oxide semiconductor, arranged on the isolating substrate and having the source electrode and the drain electrode arranged thereon,
a sensitive substrate connected to the first gate electrode and comprising functionalization species for bonding the target substance, such that the first gate electrode connected with said substrate is sensitive to the target substance, and
a second gate electrode arranged on the isolating substrate, physically separated from the first gate electrode by the channel, positioned opposite to the first gate electrode and configured to modulate the drain-source current of the channel;
and wherein the reference transistor comprises:
a reference source electrode,
a reference drain electrode,
a first reference gate electrode connected with an insensitive substrate without the functionalization species of the sensitive substrate, such that the first reference gate electrode connected with said insensitive substrate is insensitive to the target substance,
a reference channel made of the oxide semiconductor, for transmitting a reference drain-source current between the reference source electrode and the reference drain electrode, and
a second reference gate electrode physically separated from the first reference gate electrode by the reference channel,
wherein the detection transistor and the reference transistor are both placed on the isolating substrate and electrically connected to one another, wherein the second gate electrode of the detection transistor is connected to the second reference gate electrode of the reference transistor.
2 . The biosensor according to claim 1 , wherein the second gate electrode is positioned along the channel in an area to which at the opposite side of the channel there is adjacent the first gate electrode and only one of the source electrode or the drain electrode.
3 . The biosensor according to claim 1 , further comprising an encapsulation arranged such that it exposes the first gate electrode.
4 . The biosensor according to claim 1 , wherein the first gate electrode is connected with the sensitive substrate via a deposition of the substrate on the first gate electrode.
5 . The biosensor according to claim 1 , wherein the first gate electrode is connected with the sensitive substrate via a conductive path.
6 . The biosensor according to claim 5 , wherein the conductive path is selected from the group consisting of conductive film, wiring, junction connector, and electrolytic connection.
7 . The biosensor according to claim 6 , wherein the sensitive substrate is arranged on a disposable strip comprising a sheet of material with the functionalization species, for detachably connecting with the first gate electrode.
8 . The biosensor according to claim 1 , wherein the isolating substrate is elastic.
9 . The biosensor according to claim 1 , wherein the second gate electrode of the detection transistor and the second reference gate electrode of the reference transistor are arranged as a common second gate electrode of both transistors, formed from a coherent piece of material.
10 . The biosensor according to claim 9 , wherein the common second gate electrode extends from the channel of the detection transistor to the reference channel of the reference transistor, wherein said channels separate the common second gate electrode from the first gate electrodes of the detection transistor and from the first reference gate electrode of the reference transistor.
11 . The biosensor according to claim 1 , wherein the detection transistor and the reference transistor are covered with a common encapsulation.
12 . A biosensing device comprising the biosensor according to claim 1 and further comprising:
a control unit for processing measured data;
a power supply unit for powering the device; and
a data display unit for visualizing a detection result.
13 . A biosensing kit comprising:
the biosensor according to claim 1 , and
a disposable substrate unit comprising:
the sensitive substrate with functionalization species sensitive to the target substance, detachably connectable with the first gate electrode of the detection transistor.
14 . A biosensing kit comprising:
the biosensor according to claim 1 , and:
a disposable substrate unit comprising:
the sensitive substrate with functionalization species sensitive to the target substance, detachably connectable with the first gate electrode of the detection transistor, and
the insensitive substrate without functionalization species sensitive to the target substance, detachably connectable with the first reference gate electrode of the reference transistor.