The global surge in diabetes prevalence necessitates continuous advancements in glucose detection technologies. Traditional methods like blood glucose monitoring, which is effective, pose inconveniences and invasiveness for patients, driving the exploration of innovative biosensors. The challenging nature of glucose detection in complex biological environments emphasizes the importance of developing a reliable and accurate detection system. This work aimed to revolutionize glucose detection by leveraging millimeter-wave (mmWave) biosensors, capitalizing on their unique advantages for improved accuracy and non-invasiveness to enable real-time and continuous glucose monitoring, offering a more convenient and accessible solution for individuals managing diabetes. The primary goal was to fill the existing gap in glucose monitoring methods by introducing a technology capable of overcoming the limitations of traditional approaches where the sensor operates near the target tissues, ensuring precise measurements without invasive procedures or susceptibility to environmental interference. The approach involved integrating mmWave technology into biosensor applications, utilizing experimental methods and theoretical models. The mmWave captured minute changes in dielectric properties associated with varying glucose concentrations. The main results revealed the efficacy of the mmWave biosensor in accurately detecting variations in glucose levels and demonstrated enhanced sensitivity, showcasing its potential for the development of a portable and wearable biosensor system in real-world applications, thus addressing the need for continuous glucose monitoring in daily life. The results emphasize the potential of this technology to revolutionize diabetes management by providing timely and precise glucose measurements in near-field conditions, demonstrating promising levels of accuracy and sensitivity. The near-field operation of the mmWave biosensor presents distinct advantages, including reduced susceptibility to environmental interference, enhanced spatial resolution, and the potential for integration into wearable devices. This work envisions a future where mmWave biosensors transform glucose monitoring, improving life for individuals managing diabetes with accessibility.

The aim of this research activity is the design, assembly and development of a device for the rapid and efficient detection of the FKBP12 protein in biological fluids, i.e., CSF and blood. FKBP12 is a peptidyl-prolyl cis-trans isomerase with a well-established role in neurodegenerative processes and the post-surgical anti-rejection response. The proposed nanoplatform consists of a gold- or silver-coated support for a Quartz Crystal Microbalance (QCM) functionalized with a synthetic receptor, GPS-SH1, designed and synthesized specifically to bind FKBP12. The nanostructures containing the receptor were obtained via chemical adsorption of the thiolate GPS-SH1, both alone and mixed with anti-fouling spacers, to form a Self-Assembled Monolayer (SAM). In particular, we examined linear chain alkylthiols, e.g., 1-Dodecanethiol (C₁₂-SH), and a thiol-polyethylene glycol (PEG-SH), a polymer with known anti-fouling properties. The kinetics and thermodynamics of SAM formation, as well as the nanolayer structure, were obtained by means of QCM-d measurements for all harmonic frequencies. The same technique was used to monitor the adsorption of the protein on the nanosensor as a function of the FKBP12 concentration. In all cases, we observed immobilization of the protein on the SAM, but the best results in terms of the LOD and linearity range were obtained for SAMs of the GPS-SH1/C₁₂-SH 1:6 mixture. We also tested BSA and IgG, commonly present in biological fluids of interest, to demonstrate the receptor selectivity for the protein. In collaboration with clinical laboratories, the proposed platform has been tested with blood samples from real patients. The addition of ethanol after the absorption of the proteins allows the sensor to be reconditioned for further analysis. Furthermore, frequency values measured on sensors with newly prepared SAMs or on sensors aged up to six months remained unchanged, indicating a long shelf-life.

This study presents a novel method for manufacturing microfluidic paper–fabric hybrid analytical devices (μPFADs), which play a vital role in conducting diagnostic tests at the point of care (POC), especially in resource-limited environments. By circumventing the need for complex machinery or highly skilled operators, our method presents a practical solution for scaling up these POC devices. The approach involves the utilization of a folded paper structure featuring a specific pattern like a circular well or liner microchannel on either side of the fold as a mirror image, followed by inserting a piece of fabric in between the paper fold, thereby creating a sandwich-like structure. Subsequently, a PDMS (polydimethylsiloxane) elastomer with base and curing agents in a 10:1 ratio would be coated over the entire top paper and allowed to settle, enabling the penetration of PDMS down to the bottom paper through the sandwiched fabric. When sufficient PDMS penetration is achieved through visual changes on the back side of the paper, the sandwiched assembly is heated for polymerization of the PDMS. An embedded fabric-based POC device is obtained within the paper whose structure is defined by the designs on the folded paper itself. This micro paper–fabric hybrid analytical device (μPFAD) offers several noteworthy advantages as it boasts rapid fabrication times and is cost-effective, without the need for any printing machines, thereby further enhancing its suitability for no- or low-resource environments. Experimental studies with these μPFADs were conducted for the colorimetric detection of iodine, whose deficiency is a leading cause of thyroid disorders, particularly hypothyroidism. Here, starch acts as the chromogenic agent, which forms a blue-colored complex that shifts the color from purple to deep blue–black with increasing iodine concentration. The initial experimental results reveal contrasting color changes for varying levels of iodine using the proposed μPFADs, which would be useful for the early diagnosis and management of thyroid disorders

Access to clean water is a pressing global challenge, particularly in households where water quality is compromised by various factors, including bio-waste contamination. This issue is especially acute in developing countries where clean water access is limited. In response, this study introduces a novel multispectral sensing approach tailored for assessing bio-waste levels in household water, thus enhancing water safety monitoring capabilities.

The method leverages cutting-edge optoelectronic technology and microelectronics to detect and quantify bio-waste particles in liquid water. Through the integration of optical sensors with advanced electronic circuits, the system enables the seamless collection, processing, and analysis of optical data, providing a cost-effective and user-friendly solution for effective water quality monitoring.

Real-time monitoring facilitated by optical sensors allows for timely interventions to mitigate health risks associated with bio-waste contamination in water consumption. The utilization of electronic circuits ensures the reliability and accuracy of data, empowering users to make informed decisions regarding water usage and consumption habits.

Ultimately, the primary aim of this research is to empower households to safeguard the health and well-being of their family members by ensuring access to clean and safe drinking water, particularly in the presence of bio-waste contamination. By addressing the urgent need for localized bio-waste-related water safety management, this approach offers a practical solution to a critical issue.

Furthermore, the study underscores the importance of leveraging technology to tackle bio-waste contamination challenges, especially in resource-constrained environments where traditional monitoring methods may fall short. By harnessing the power of optical sensing and microelectronics, scalable solutions for clean water access at the household level are developed.

In conclusion, the integration of optical sensor-based assessment of bio-waste levels represents a promising avenue for enhancing home water safety monitoring capabilities, thereby significantly contributing to improving public health outcomes.

Due to the SARS-CoV-2 pandemic, there were several techniques developed for COVID-19 diagnosis such as real-time polymerase chain reaction (RT-PCR) providing high performances of sensitivity, specificity, and accuracy. Several approaches such as biological detection were alternatively developed based on rapid, effective, and non-invasive. This technique of bio-detection used military trained dogs to differentiate between infected COVID-19 patients and non-infected COVID-19 by sniffing of body odors or human sweats by trained to recognize and respond to the unique VOCs patterns of COVID-19 patients’ sweat samples, which provided fast and high sensitivity results. However, potential compounds suspected to be VOCs markers that training dogs recognized from sniffing had not been clarified enough. A challenge is to identify VOCs markers that dogs recognize and differentiate for SARS-CoV-2. Gas chromatography-mass spectrometry (GC-MS) has been widely used for VOCs identification coupled with the use of headspace-solid phase microextraction (HS-SPME) as an extraction method because of its ability to directly extract volatiles without solvent consumption. Potential biomarkers can be obtained from data analysis using alignment and statistic analysis program that can categorize all identified compounds into groups. The potential markers derived from this research included nonanal, and aromatic compounds. These biomarkers' production would relate to changes in metabolism pathways in the patient’s body after COVID-19 infection. The researcher anticipated that this study would have practical implications for improving COVID-19 screening by training dogs in the future.

Due to an outbreak of COVID-19 pandemic in recent years, the emerging variants of SARS-CoV-2 causing diagnostic challenges. The rapid, non-invasive diagnostic is an urgent need to differentiate between infected with asymptomatic or symptomatic individuals and uninfected with COVID-19 to control the silent virus spreading in the community. This research developed alternative method of detecting COVID-19, in these approaches mainly focused on volatile organic compound (VOCs) in armpit sweat samples derived from population in Thailand, during variants occurring between April 2021 to May 2023, including Delta and Omicron BA.1/BA.2. VOCs odor emission produced in response to inflammation and infection from SARS-CoV-2 infection body by Gerstel Multi-purpose sampler, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS) technique with the total of 150 collected sweat samples with 75 negative confirmed COVID-19 and 75 positive confirmed COVID-19 cases (asymptomatic/symptomatic) used to identified potential biomarkers for COVID-19 related with peak areas of chromatogram results. The statistical analysis of ROC curves including classification rate indices of sensitivity, specificity and accuracy of the different potential markers for armpit sweat samples in GC-MS allowed potential VOCs biomarkers to discriminate the COVID-19 patients as nonanal and aromatic compounds (up to 92% sensitivity, 97% selectivity, and 96% specificity), respectively, and validated the results by comparison with the RT-PCR gold standard technique.

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) caused a pandemic COVID-19 disease worldwide, generating an urgent need to develop an early diagnosis approach. This work applied trained dogs to perform a sniff test for COVID-19 screening based on the detection of volatile organic compound (VOC) markers in sweat. Male and female Labrador Retrievers participated in this research as sniffer dogs. The samples were collected from the armpit sweat of PCR-positive (symptomatic/asymptomatic) and -negative patients admitted at Chulalongkorn University Hospital, Bangkok, Thailand. Two cotton rods were used to collect the samples from each patient and kept in 20 mL screw headspace glass vials closed with aluminum caps. The virus inactivation on the surface was performed under UV radiation and left at 25 ºC inside a biosafety laboratory level 2 (BSL2) at Chulalongkorn University Hospital for 48 hours. The cotton swabs from each patient were transferred from the glass vial into a stainless steel bottle with dimensions of 5 x 9.5 cm. The dog training process was based on positive reinforcement approaches, involving memorizing the COVID-19 positive and negative samples which were hanging in an I-shaped stand. A COVID-19 screening test evaluation (accuracy, sensitivity, and specificity) was carried out using a six-armed spinning wheel. The sniffer dogs successfully recognized VOC markers for SARS-CoV-2 patients with a success rate of 96% (n=300). In conclusion, the COVID-19 sniffer dogs have the capability for participating in COVID-19 point-of-care testing in public areas in Bangkok, Thailand.

Over the last few years, flexible electronics have been resonating in a wide variety of novel (bio)applications. As a key component, electrolyte-gated organic field-effect transistors (EGOFETs) are attracting considerable interest for their inherent advantages in miniaturization, low cost fabrication using solution processing methods, low power consumption, and label- free transduction, among others. Bearing this in mind, the idea in this study is to manufacture a novel EGOFET replacing the liquid electrolyte, which acts as dielectric, for new electrolyte platforms (i.e. hydrogels). This could overcome the limitations that aqueous media present. This material employed as an electrolyte provides OFETs with good mechanical properties and excellent biocompatibility, offering a suitable environment for the immobilization of biomolecules. The experimental approach involves the fabrication and characterization of an EGOFET using an organic semiconductor (OSC) as the active material and different dielectric media. For this reason, our proposal is to fabricate EGOFETs using a processing technique compatible with roll-to-roll processing (i.e. bar-assisted meniscus shearing (BAMS)), which allows the deposition of a layer of OSC blended with polystyrene (PS). Subsequently, the devices were characterized electrically by means of Transfer and Output Characteristics in order to demonstrate that the electrical parameters between both devices are comparable in terms of sensitivity. This work demonstrates that these devices based on hydrogels exhibit comparable electrical performance and long-term stability to those employing liquid electrolytes, and therefore they could be employed in several applications such as sensors of (bio)analytes of interest and point-of-care (POC) devices,. In conclusion, this research underscores the promising prospects of EGOFETs in transforming point-of-care testing. The integration of organic semiconductors and electrolyte gating not only enhances device sensitivity but also offers cost-effective and portable solutions for diagnostic applications. Future research may further refine and expand the applications of EGOFETs, paving the way for widespread adoption in routine diagnostic practices.

Fluorescent nanodiamonds (FNDs) now underlie cutting-edge quantum precision measurements, owing to the rigorous spin qubit out of their negative-charged nitrogen vacancies (NV⁻) that are manipulable and scalable at ambient conditions (the DiVincenzo criteria). Though the FND-based ODMR (optically detected magnetic resonance) technique has already achieved an ultimate sensitivity down to the subcellular organelle or even monomolecular levels, confocal microimaging as a benchmarked setup must cohere microwaves with the Zeeman-split ±1 states (³E in spectral terms) of a rare single particle in a programmed pulse sequence. It is not easy to integrate such intricate instrumentation into some transportable benchtop devices, and then adapt these devices for point-of-care testing (POCT) scenarios in dire needs, for instance, a PCR-free dipstick reader that can be used for inspection during the COVID-19 pandemic in a resource-limited community.

The individual quantized eigenvectors of multiple NV⁻ spins in an FND ensemble can actually be modulated in unison once subjected to a strong alternating magnetic field (≥50 mT in our case), which would provide not only a nanofabricated chip-set for microwave coherence, but also the lens group for feeble signal amplification. By surface chemistry, biotinylated FNDs of a uniform size (~10 nm) were tagged with the model SARS-CoV-2 N-protein antibodies as a probe upon the Conjugate Pad of a lateral flow test strip. Following the standard LFA protocol, well-dispersed FNDs mounted on the T line, where their blinking photoluminescence emissions (λ_em = 632 nm, excited at 543 nm) were routed out via an optical fiber, were recorded and further processed with machine learning quantum computation for lock-in enhancement of timelapse captures in a swift and streamlined fashion.

The electronic nose, an innovative system designed to emulate the olfactory capabilities of biological organisms, shows promising utility across various sectors, including environmental monitoring, disease diagnosis, public safety, and food engineering. The effectiveness of electronic noses largely depends on the sensitivity and selectivity of their gas sensors, which currently face challenges in these areas.

To address these limitations, a chemiresistive gas sensor was fabricated with a gas-sensitive material comprising mesoporous lanthanum-doped tin dioxide spheres, utilizing a self-templating approach coupled with direct thermal decomposition. The spheres had a uniform size (~77 nm in diameter), large pore size (~5.7 nm), and high specific surface area (52-59 m²/g). Based on these characteristics, the chemiresistive gas sensor exhibited exceptional performance in the detection of glutaraldehyde, with a high response value (13.5@10 ppm), rapid response time (28 s), remarkable stability, and a low detection limit (0.16 ppm). The observed sensitivity was threefold higher than that of sensors made from undoped mesoporous tin dioxide spheres. This enhancement could be attributed to lanthanum's ability to improve oxygen diffusion, adsorption, and ionization on the material's surface, thereby increasing the electron depletion layer's thickness and detection sensitivity. Density Functional Theory (DFT) calculations further confirmed that lanthanum doping enhanced the adsorption energy towards glutaraldehyde molecules, facilitating electron transfer and improving sensor performance.

By doping gas-sensitive materials with rare earth elements, it is possible to modulate the interaction between gas molecules and the material's surface interface, significantly improving gas sensing performance. This study not only advances the development of high-performance sensors for glutaraldehyde disinfectants but also lays the groundwork for designing advanced gas sensors and enhancing the capabilities of electronic noses.

This work has been published in ACS Sensors (https://pubs.acs.org/doi/10.1021/acssensors.3c00953) and has been selected as the Front Cover.