The objective of this work is to develop a methodology and associated platform for nucleic acid detection at the point-of-care (POC) that is sensitive, user-friendly, affordable, rapid, and robust. The heart of this system is an acoustic wave sensor, based on a Surface Acoustic Wave (SAW) or Quartz Crystal Microbalance (QCM) device, which is employed for the label-free detection of isothermally amplified target DNA. Nucleic acids amplification and detection is demonstrated inside three crude human samples, i.e., whole blood, saliva, and nasal swab, spiked in with 10–100 Salmonella cells. To qualify for POC applications, a portable platform was developed based on 3D printing, integrating inside a single box: (i) simple fluidics based on plastic tubing and a mini peristaltic pump, (ii) a heating plate combined with disposable reaction tubes for isothermal amplification; (iii) a mini antenna analyzer operated through a tablet; and (iv) an acoustic wave device housing unit. The simplicity of the method combined with smartphone operation and detection, rapid sample-to-answer analysis time (30 min), and high performance (detection limit 4 × 10³ CFU/ml) in three of the most important human samples in diagnostics suggest that the methodology could become a tool of choice for nucleic acid detection at the POC. In addition, the low cost of the platform and assay holds promise for its adoption in resource limited areas. The acoustic detection method is shown to give similar results with a standard colorimetric assay carried out in saliva and nasal swab but can also be used to detect nucleic acids inside whole blood, where a colorimetric assay failed to perform.

Gait analysis refers to the systematic study of human locomotion and finds numerous applications in the fields of clinical monitoring, rehabilitation, sports science and robotics. Wearable sensors for real-time gait monitoring have emerged as an attractive alternative to the traditional clinical-based techniques, owing to their low cost and portability. In addition, 3D printing technology has recently drawn increased interest for the manufacturing of sensors, considering the advantages of diminished fabrication cost and time. In this study, we report the development of a 3D-printed capacitive smart insole for the measurement of plantar pressure. Initially, a novel 3D-printed capacitive pressure sensor was fabricated and its sensing performance was evaluated. The sensor exhibited a sensitivity of $1.19 \mathrm{MP}{\mathrm{a}}^{-1}$, a wide working pressure range $\left(<872.4 \mathrm{kPa}\right)$, excellent stability and durability (at least $2.280$ cycles), great linearity ($R^2=0.993$), fast response/recovery time $\left(142–160 \mathrm{ms}\right)$, low hysteresis $(DH<10\%)$ and the ability to support a broad spectrum of gait speeds $(30–70$ steps/min). Subsequently, 16 pressure sensors were integrated into a 3D-printed smart insole that was successfully applied for dynamic plantar pressure mapping and proven able to distinguish the various gait phases. We consider that the smart insole presented here is a simple, easy to manufacture and cost-effective solution with the potential for real-world applications.

Lamb-wave devices are characterized by high sensitivity to surface perturbations due to acoustic energy confinement in a thin piezoelectric membrane. In this paper, a Lamb-wave delay line device based on a single crystalline GaN membrane is presented. The observed operating frequency of 178.82 MHz was found to be in excellent agreement with numerical analysis predictions. The device as a chemical sensor was evaluated during the application of various concentrations of glycerol on the device surface; its ability to operate as a biosensor was also assessed during the detection of the specific binding of a protein (IgG) to the device surface.

Discovery of molecular targets or compounds that alter neuronal function can lead to therapeutic advances that ameliorate age-related neurodegenerative pathologies. Currently, there is a lack of in vivo screening technologies for the discovery of compounds that affect the age-dependent neuronal physiology. Here, we present a high-throughput, microfluidic-based assay for automated manipulation and on-chip monitoring and analysis of stimulus-evoked calcium responses of intact C. elegans at various life stages. First, we successfully applied our technology to quantify the effects of aging and age-related genetic and chemical factors in the calcium transients of the ASH sensory neuron. We then performed a large-scale screen of a library of 107 FDA-approved compounds to identify hits that prevented the age-dependent functional deterioration of ASH. The robust performance of our assay makes it a valuable tool for future high-throughput applications based on in vivo functional imaging.

Surface plasmon resonance (SPR) and Love wave (LW) surface acoustic wave (SAW) sensors have been established as reliable biosensing technologies for label-free, real-time monitoring of biomolecular interactions. This work reports the development of a combined SPR/LW-SAW platform to facilitate simultaneous optical and acoustic measurements for the investigation of biomolecules binding on a single surface. The system’s output provides recordings of two acoustic parameters, phase and amplitude of a Love wave, synchronized with SPR readings. We present the design and manufacturing of a novel experimental set-up employing, in addition to the SPR/LW-SAW device, a 3D-printed plastic holder combined with a PDMS microfluidic cell so that the platform can be used in a flow-through mode. The system was evaluated in a systematic study of the optical and acoustic responses for different surface perturbations, i.e., rigid mass loading (Au deposition), pure viscous loading (glycerol and sucrose solutions) and protein adsorption (BSA). Our results provide the theoretical and experimental basis for future application of the combined system to other biochemical and biophysical studies.