Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered “gold‐standard” device coatings to reduce biofouling. To discover novel anti‐biofouling materials, a combinatorial library of polyacrylamide‐based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet‐rich plasma in a high‐throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti‐biofouling properties over current gold‐standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti‐biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small‐molecule drug in vivo better than gold‐standard coatings. The novel methodology described enables the discovery of anti‐biofouling materials that can extend the lifetime of real‐time in vivo sensing devices.

This paper presents an inductorless circuit technique for CMOS limiting amplifiers. By employing the third-order interleaving active feedback, the bandwidth of the proposed circuit can be effectively enhanced while maintaining a suppressed gain peaking within the frequency band. Using a standard 0.18-m CMOS process, the limiting amplifier is implemented for 10-Gb/s broadband applications. Consuming a DC power of 189 mW from a 1.8-V supply voltage, the fabricated circuit exhibits a voltage gain of 42 dB and a 3-dB bandwidth of 9 GHz. With a 2 31 1 pseudo-random bit sequence at 10 Gb/s, the measured output swing and input sensitivity for a bit-error rate of 10 12 are 300 and 10 mV pp , respectively. Due to the absence of the spiral inductors, the chip size of the limiting amplifier including the pads is 0.68 0.8 mm 2 where the active circuit area only occupies 0.32 0.6 mm 2 .

Frequency dividers and VCOs are the most critical building blocks for the implementation of high-frequency signal sources that are widely used in wireline and wireless communication systems. In this paper, circuit topologies are presented to improve the performance of these high-frequency components. For the frequency divider, the proposed g m -enhancement technique incorporates the series and shunt inductive peaking in the resonator design. With the regenerative mechanism in the injection-locked frequency divider, a wide locking range can be achieved without using varactors for frequency tuning. As for the VCO, a balanced architecture is proposed for low phase noise while relaxing the stringent requirement on the start-up conditions at higher frequencies. Both of the circuits are designed and fabricated in a 0.18µm CMOS process.Injection-locked frequency dividers loaded with on-chip resonators are used to provide high-speed frequency division at low power consumption [1]. However, the limited locking range due to the high-Q resonators makes it difficult to cover the frequency tuning range of the VCOs under process and temperature variations. Tuning the free-running frequency with the varactors at the cost of a more complicated controlled mechanism when the divider is integrated in a system can extend the operating range of the divider. Alternatively, a regenerative divider with inductive loads presents an enhanced input bandwidth [2]. Due to the use of the mixer in the regenerative loop, higher power consumption is typically required. To overcome the design limitations, a g menhancement technique to increase the loop gain for regenerative frequency division is proposed. Figure 30.4.1 shows the block diagram of a regenerative divider that consists of a feedback loop with a mixer and a band-pass filter. As the input signal ω in mixes with the feedback signal ω in /2, frequency components of 3ω in /2 and ω in /2 are generated at the output of the mixer. With the selectivity of the LC-tank, frequency division is achieved provided that the open-loop gain for the component at ω in /2 exceeds unity. Consequently, it is desirable to maximize theloop-gain in the circuit design for wideband operations. A conventional circuit topology of the frequency divider is shown in Fig. 30.4.1, where the switching transistor M 1 acts as the mixer and the cross-coupled pair with the LC-tank forms the feedback loop [3]. As the RF signal applies at the gate, M 1 can be treated as a passive drainpumped mixer [4]. By biasing the gate voltage higher than the threshold voltage, the transconductance of M 1 is a nonlinear function of the drain voltage V ds . To maximize the effective transconductance g m,eff for an enhanced conversion gain, a series inductive peaking technique is adopted. By inserting the inductor L s in series with M 1 , the effective drain voltage V ds,eff increases as long as ω s >√[(ω LO 2 +ω d 2 )/2], where ω s =(L s C d ) -1 and ω d =(R ds C d ) -1 . Note that the maximum V ds,eff is obtained with ω s =√(ω LO 2 +ω d 2 )...

This work presents a microfluidics-integrated label-free flow cytometry-on-a-CMOS platform for the characterization of the cytoplasm dielectric properties at microwave frequencies. Compared with MHz impedance cytometers, operating at GHz frequencies offers direct intracellular permittivity probing due to electric fields penetrating through the cellular membrane. To overcome the detection challenges at high frequencies, the spectrometer employs on-chip oscillator-based sensors, which embeds simultaneous frequency generation, electrode excitation, and signal detection capabilities. By employing an injection-locking phase-detection technique, the spectrometer offers state-of-the-art sensitivity, achieving a less than 1 aFrms capacitance detection limit (or 5 ppm in frequency-shift) at a 100 kHz noise filtering bandwidth, enabling high throughput (>1k cells per s), with a measured cellular SNR of more than 28 dB. With CMOS/microfluidics co-design, we distribute four sensing channels at 6.5, 11, 17.5, and 30 GHz in an arrayed format whereas the frequencies are selected to center around the water relaxation frequency at 18 GHz. An issue in the integration of CMOS and microfluidics due to size mismatch is also addressed through introducing a cost-efficient epoxy-molding technique. With 3-D hydrodynamic focusing microfluidics, we perform characterization on four different cell lines including two breast cell lines (MCF-10A and MDA-MB-231) and two leukocyte cell lines (K-562 and THP-1). After normalizing the higher frequency signals to the 6.5 GHz ones, the size-independent dielectric opacity shows a differentiable distribution at 17.5 GHz between normal (0.905 ± 0.160, mean ± std.) and highly metastatic (1.033 ± 0.107) breast cells with p ≪ 0.001.