Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Design and Analysis of a Sample-and-Hold CMOS Electrochemical Sensor for
  Aptamer-based Therapeutic Drug Monitoring   In this paper, we present the design and the analysis of an electrochemical
circuit for measuring the concentrations of therapeutic drugs using
structure-switching aptamers. Aptamers are single-stranded nucleic acids, whose
sequence is selected to exhibit high affinity and specificity toward a
molecular target, and change its conformation upon binding. This property, when
coupled with a redox reporter and electrochemical detection, enables
reagent-free biosensing with a sub-minute temporal resolution for in vivo
therapeutic drug monitoring. Specifically, we design a chronoamperometry-based
electrochemical circuit that measures the direct changes in the electron
transfer (ET) kinetics of a methylene blue reporter conjugated at the
distal-end of the aptamer. To overcome the high-frequency noise amplification
issue when interfacing with a large-size (> 0.25 mm2) implantable electrode, we
present a sample-and-hold (S/H) circuit technique in which the desired
electrode potentials are held onto noiseless capacitors during the recording of
the redox currents. This allows disconnecting the feedback amplifiers to avoid
its noise injection while reducing the total power consumption. A prototype
circuit implemented in 65-nm CMOS demonstrates a cell-capacitance-insensitive
input-referred noise (IRN) current of 15.2 pArms at a 2.5-kHz filtering
bandwidth. Tested in human whole blood samples, changes in the ET kinetics from
the redox-labeled aminoglycoside aptamers at different kanamycin concentrations
are measured from the recorded current waveforms. By employing principal
component analysis (PCA) to compensate for the sampling errors, a detection
limit (SNR = 1) of 3.1 uM under 1-sec acquisition is achieved at 0.22-mW power
consumption.

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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
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The categories of this paper are: econ
1
The categories of this paper are: cs
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The categories of this paper are: acc-phys
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The categories of this paper are: stat