Microneedle technologies have been developed for dermal drug and vaccine delivery, including hollow-, solid-, coated-, and dissolving microneedles. Microneedles have been made in many different geometries and of many different materials, all of which may influence their skin-penetrating ability. To ensure reproducible and effective drug and vaccine delivery via microneedles, the optimal insertion parameters should be known. Therefore, a digitally-controlled microneedle applicator was developed to insert microneedles into the skin via impact insertion (velocity) or via pressing force insertion. Six microneedle arrays with different geometries and/or materials were applied onto ex vivo human skin with varying velocities or pressing forces. Penetration efficiency and delivered antigen dose into the skin after application of microneedles were determined. In general, microneedles pierced the skin more efficiently when applied by impact application as compared to application via pressing force. However, the angle of application of the applicator on the skin can affect the velocity of the impact, influencing the penetration efficiency of microneedles. Regarding the antigen delivery into the skin, the delivered dose was increasing by increasing the velocity or pressure, and thus, increasing the penetration efficiency. These data demonstrate that an applicator is an important tool to determine optimal application conditions with ex vivo human skin.

Electroencephalography (EEG) is an important clinical tool for monitoring neurological health. However, the required equipment, expertise, and patient preparation inhibits its use outside of tertiary care. Non-experts struggle to obtain high-quality EEG due to its low amplitude and artefact susceptibility. Wet electrodes are currently used, which require abrasive/conductive gels to reduce skin-electrode impedance. Advances in dry electrodes, which do not require gels, have simplified this process. However, the assessment of dry electrodes on neonates is limited due to health and safety barriers. This study presents a simulation framework for assessing the quality of EEG systems using a neonatal EEG database, without the use of human participants. The framework is used to evaluate a low-cost EEG acquisition system and compare performance of wet and dry (Micro Transdermal Interface Platforms (MicroTIPs), g.tec-g.SAHARA) electrodes using accurately acquired impedance models. A separate experiment assessing the electrodes on adult participants was conducted to verify the simulation framework’s efficacy. Dry electrodes have higher impedance than wet electrodes, causing a reduction in signal quality. However, MicroTIPs perform comparably to wet electrodes at the frontal region and g.tec-g.SAHARA performs well at the occipital region. Using the simulation framework, a 25dB signal-to-noise ratio (SNR) was obtained for the low-cost EEG system. The tests on adults closely matched the simulated results.

Parkinson’s disease is a degenerative neurological disorder that impairs motor functions and is accompanied by a wide range of non-motor symptoms, such as sleep problems. Parkinsonism is assessed during clinical evaluations and via self-administered diaries and, based on these, the required medication therapies are provided to lessen symptoms. Tri-axial accelerometers and gyroscopes have the potential utility to objectively assess the patient’s condition and aid clinicians in their decision-making. People with Parkinson’s often have significant abnormalities in blood pressure due to comorbid age-related cardiovascular disease and orthostatic hypotension, which result in blurred vision, dizziness, and falls. Frequent blood pressure monitoring may aid in the evaluation of such events and differentiate Parkinson’s disease symptoms from those originated by hypotension. In the present paper, a novel technology for the remote monitoring of Parkinsonian symptoms is presented: the WESAA system. It consists of two devices, worn on the wrist and ankle; its main function is to record accelerations and angular velocities from these body parts, together with photoplethysmograph and electrocardiogram data. This information can be elaborated offline to measure common Parkinson’s disease motor symptoms (e.g., tremor, bradykinesia, and dyskinesia), as well as gait speed, sleep-wake cycles, and cuff-less blood pressure measurements. The overall system requirements, market overview, industrial design and ergonomics, system development, user experience, early results of the gathered inertial raw data, and validation of the photoplethysmograph and electrocardiogram signal waveforms are all thoroughly discussed. The developed technology satisfies all system requirements, and the sensors adopted provided outcomes comparable with gold standard techniques.

We present amperometric sensors based on direct electron transfer enzyme (DET) for the detection of lactate, which is an important medical parameter present in blood and interstitial dermal fluid (ISF). For measurement in blood, we present aplanar screen-printedbiosensor withcarbon working electrodes, whilefor the intendedmeasurement in ISF, we investigated platinum-metallized epoxy microneedle sensors. On both sensor types a bioink was applied, consisting of a DET enzyme mixed with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). As second layer, a hydrogel layer is deposited to hold the enzyme on site. Local modification of the platinum microneedle sensors was performed by non-contact spotting. The developed modification enables the detection of lactate at a potential of 0 V with response times of 500-700 s. For carbon sensors, a limit of detection of 0.12 mM lactate was determined, and two linear ranges of 0.3-5 mM and 10-50 mM were observed with sensitivities of 319 and 9.6 nA/(mm2·mM), respectively. For locally modified platinum microneedle sensors two linear ranges of 0.3-2.5 mM and 5-30.5 mM were observed with sensitivities of 322.5 and 3.7 nA/(mm ² ·mM), respectively. Given the low sensitivities in the higher concentration range, saturation for carbon sensors and locally modified platinum microneedle sensors starts at 10 mM and 5 mM lactate, respectively. Thus, both sensors allow sensitive measurements in the lower concentration range. Current densities at saturating lactate concentration are higher on freshly prepared carbon electrodes with 1.80 μA/mm ² (10 mM) compared to platinum microneedle electrodes with 0.75 μA/mm ² (10 mM) with full electrode modification. For platinum microneedle electrodes with optimized, dried local microneedle modification a current density of 0.95 μA/mm2 (5 mM) was measured. Detection of lactate in whole blood was demonstrated on carbon sensors, showing increasing currents after exercise, correlating with higher blood lactate levels, measured with a test strip reference system.

Wearable dry electrodes facilitate continuous long-term electrocardiogram (ECG) monitoring, which is beneficial for the early diagnosis and management of heart disease. However, existing dry electrode technologies face limitations in maintaining clinically acceptable signal quality during movement, restricting their usability when patients are active. This is particularly critical for cardiac patients—such as those with arrhythmias or heart failure—who benefit from continuous monitoring during daily activities, exercise, or rehabilitation, where motion artefacts often obscure clinically relevant ECG features. To address this gap, we present microneedle (MN) dry electrodes, manufactured using a cost-effective industrial injection moulding process that is scalable for mass. We performed a study on a small cohort of healthy volunteers, to compare the ECG signal quality recorded using MN dry electrodes with that obtained using conventional gel electrodes, under both static and ambulatory conditions. Signal quality was statistically assessed using parameters such as ECG waveform morphology, R-peak-to-peak interval, and heart rate variability (HRV) time-domain. The results demonstrate that MN dry electrodes exhibit signal quality comparable to that of wet electrodes, even under ambulatory motion. This finding highlights the novelty of a low-cost, mass-producible microneedle electrode technology that could bridge the gap between experimental dry electrodes and clinically accepted wet electrodes.