Saliva sampling: Methods and devices. An overview

Transformative biomedical devices to overcome biomatrix effects

The emergence of high-performance biomedical devices and sensing technologies highlights the technological advancements in the field. Recently during COVID-19 pandemic, biosensors played an important role in medical diagnostics and disease monitoring. In the past few decades, biosensors have made impressive advances in terms of sensing capability, methodology, and applications, and modern biosensors show higher performance and functionality compared to traditional biosensing platforms. Currently, various biomedical devices are already in the market or on the verge of commercialization, such as disposable paper-based devices, lab-on-a-chip devices, wearable sensors, and artificial intelligence-assisted systems, all contributing to the evolution of digital health. Despite the promising features of detection methods for developing practical biosensors, there are substantial barriers to the commercialization of biomedical devices. An important challenge is the matrix effect in the detection of clinical samples. Although achieving low limit of detection values under controlled laboratory conditions is feasible, maintaining performance in real clinical samples is difficult. Matrix molecules present in these samples can interact with analytes, potentially affecting sensitivity, specificity, and sensor response. Approaches to reduce nonspecific adsorption and cross-reactivity are imperative for improving sensor performance. The detection of diagnostic biomarkers in complex biological matrices often requires laborious sample preparation, which may affect accuracy and precision. In this review, we highlight the recent efforts to detect analytes in real samples, both invasively and noninvasively, and underline technological advancements that mitigate the biomatrix effects. We also discuss commercially available biosensors and technologies promising commercial success, highlighting their potential effect on healthcare and diagnostics.

Strategic approaches to assess and quantify the oxidative stress biomarkers in complex biological systems

Oxidative stress (OS) is an emerging research area in clinical and biological sciences due to its association with various diseases and physiological processes. OS occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body's ability to neutralize or repair the damage caused. Chronic oxidative stress is linked to diseases like diabetes, cardiovascular diseases, cancer, and neurodegenerative disorders. Accurate monitoring of OS is crucial for diagnosing diseases, evaluating disease progression, and predicting clinical results. Despite challenges in measuring free radicals due to their short half-life and low concentrations, it can be indirectly assessed through biomarkers like lipid peroxidation, DNA damage, and protein oxidation. The most effective analytical techniques for assessing OS biomarkers in various biological fluids were developed. Furthermore, an in-depth exploration of these various analytical methodologies, underscoring their sensitivity, specificity, and reliability in detecting low concentrations of biomarkers across complex matrices is necessary. A comprehensive literature search was conducted using databases such as Google Scholar, PubMed and Reaxys to identify relevant studies on OS biomarkers. This review explores the evolution of these techniques, highlighting advancements in sample preparation procedures and the specifications of each technique, offering a thorough evaluation of biomarker analysis.

Saliva analysis using metal-organic framework-coated miniaturized vials

BACKGROUND

In-vial microextraction is probably the simplest microextraction technique because it eliminates centrifugation and/or filtration steps while offering short extraction and desorption times. However, it has had limited applicability, mostly involving polydimethylsiloxane coatings and gas chromatography applications. Quite recently, one study introduced metal-organic framework (MOF)-coated glass vials for environmental analyses and liquid chromatography, thus combining the advantages of MOFs as adsorbents with the advantages of the in-vial approach, while not limiting the application to volatile analyses. Besides, a much higher exposure of the MOF to the sample due to the thin film coating available within the vial's inner walls is attained. Clearly, the applicability of this format for bioanalysis has not been evaluated, as there are not many stable and reusable sorbents useful for biological samples presenting high protein content. Besides, the in-vial technique must demonstrate to be valid for low-availability samples, such as saliva.

RESULTS

A vial with 2 mL-capacity and coated uniformly with a MOF has been developed to analyze saliva in a thin film solid-phase microextraction approach, while keeping an adequate analytical performance using only 50 μL of solvent for desorption. The procedure only requires 12.5 min of operation. Interestingly, the issues related to pore-blocking of the crystalline materials by proteins present in the saliva samples are solved with a simple cleaning protocol that also ensures a high reusability of the vials (more than 50 times). Seven bisphenols were determined in saliva with these devices, reaching limits of detection down to 0.10 μg L-1, and with inter-vial and inter-day precision values as RSD (in %) lower than 15% at a low concentration level (2.0 μg L-1).

SIGNIFICANCE

A device is presented to analyze complex saliva samples with a novel miniaturized MOF-coated vial ensuring proper reusability, while addressing the challenge of protein clogging and, at the same time, keeping adequate analytical performance with short analysis times. This approach represents significant progress in the bioanalytical sample preparation field, particularly when using sorbent porous materials integrated within miniaturized devices.

A Novel Sugar-Free Probiotic Oral Rinse Influences Oral Candida albicans in Children with Down Syndrome Post Complete Oral Rehabilitation: A Pilot Randomized Clinical Trial with 6-Month Follow-Up

Down syndrome (DS), caused by trisomy 21, affects 1 in 600-1000 live births and is associated with distinctive physical features, cognitive impairment, and oral health challenges such as increased susceptibility to dental caries, periodontal disease, and elevated prevalence of oral Candida spp. Barriers to dental care necessitate comprehensive strategies to address the unique oral health needs of children with DS. The aim of the study was to evaluate the effectiveness of a sugar-free probiotic oral rinse versus 0.2% chlorhexidine digluconate in reducing oral Candida albicans (OCA) counts and improving oral health outcomes in children with DS. A double-blind randomized controlled trial (CTRI/2022/10/046847) enrolled 30 children with DS (aged 6-14 years). Baseline evaluations included OCA quantification and oral health assessments (OHI-S and PHP). Following individualized oral rehabilitation, participants were randomized to either a probiotic rinse (Group 1) or chlorhexidine rinse (Group 2) for 2 weeks. OCA and oral health parameters were assessed at baseline (T0), 2 weeks post-rehabilitation (T1), 2 weeks post-rinse (T2), and 6 months post-rinse (T3). Both groups showed significant improvements in OHI-S and PHP scores (p < 0.05). The probiotic group demonstrated significantly lower OCA counts than the chlorhexidine group at T2 and T3 (p = 0.001). Hence, the probiotic oral rinse can be considered a safe, effective method for reducing OCA and improving oral health outcomes in children with DS, advocating its inclusion in oral health management strategies for this population.

From automated Raman to cost-effective nanoparticle-on-film (NPoF) SERS spectroscopy: A combined approach for assessing micro- and nanoplastics released into the oral cavity from chewing gum

Microplastics (MPs) and Nanoplastics (NPs), a burgeoning health hazard, often go unnoticed due to suboptimal analytical tools, making their way inside our bodies through various means. Surface Enhanced Raman Spectroscopy (SERS), although is utilized in detecting NPs, challenges arise at low concentrations due to their low Raman cross section and inability to situate within hotspots owing to their ubiquitous size and shape. This study presents an innovative and cost-effective approach employing household metallic foils (aluminium and copper) as nanoparticle-on-film (NPoF) substrates for targeting such analytes. Leveraging from the near field enhancements due to plasmonic coupling amidst third-generation hotspots (TGHs) and second-generation hotspots (SGHs), the enhanced SERS activity is achieved. Furthermore, following an extensive comparison of the substrates' flexibility, sensitivity, reproducibility, and robustness, the copper foil-based NPoF platform was used to detect 100 nm polystyrene plastics down to 1 μg/ml concentration. Subsequently, a systematic detection of more than 250,000 MPs with automated Raman spectroscopy was performed, followed by the detection of NPs using SERS with a NPoF substrate in saliva samples released from the gum base in the oral cavity during a one-hour chewing activity. Overall, we report a cost-effective and versatile NPoF substrate, having the potential to screen a diverse array of environmental pollutants envisioned as a potential point-of-site tool by coupling it with a handheld Raman instrument.

Dispersive microextraction techniques as efficient strategies for the analysis of saliva: A comprehensive review

This review article brings together two of the current hot-spots in the field of analytical chemistry, and more specifically in the sample preparation stage: the use of dispersive microextraction techniques, and the analysis of saliva. Due to saliva collection is minimally invasive, it is increasingly being considered in bioanalysis. Moreover, bioanalysis is routine and agglutinates a high number of samples demanding for fast results, thus high-throughput assays are highly required. On the other hand, if something characterizes biological matrices, including saliva, is their complex composition. To adapt the matrix to the analytical method to be applied and to avoid as far as possible the matrix effect, an efficient sample preparation stage is required. To this regard dispersive microextraction techniques, as rapid, efficient and sustainable sample preparation approaches, play a crucial role. In the first part of the review, different workflows for the collection and pretreatment will be briefly described, placing special emphasis on advice to follow. Then, a compilation of the different applications of dispersive techniques for the analysis of saliva is presented, in which the trends observed in both specific analytes and microextraction approaches used are discussed.

Exploring Saliva as a Sample for Non-Invasive Glycemic Monitoring in Diabetes: A Scoping Review

Background/Objectives: Diabetes mellitus is characterized by a dysregulated glucose metabolism, necessitating frequent and often invasive monitoring techniques for its effective management. Saliva, a non-invasive and readily accessible biofluid, has been proposed as a potential alternative for glycemic monitoring due to its biochemical correlation with blood glucose levels. This scoping review aims to evaluate the evidence regarding the use of salivary glucose as a biomarker to track glycemic changes in diabetic populations. Methods: This study adhered to the Joanna Briggs Institute guidelines and the PRISMA Extension for Scoping Reviews. A literature search was performed across the PubMed, Scopus, and Web of Science databases, supplemented by manual searches. Results: A total of fifty-seven studies were included, representing populations affected by type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes (GD). The findings indicated consistent positive correlations between the salivary and blood glucose levels in most studies, although there were significant variations in the sensitivity, specificity, and methodological approaches. Salivary glucose showed promise as a complementary biomarker for glycemic monitoring, particularly due to its non-invasive nature. Conclusions: Challenges such as variability in salivary composition, the absence of standardized collection protocols, and the limited availability of portable devices were noted. This review highlights the potential of saliva as an adjunct sample for diabetes management while stressing the need for further research to bridge existing gaps.

Evaluation of Saliva Collection and DNA Extraction Methods for Practical Application of Salivary Human Herpesvirus 6 and 7 Assays

Salivary human herpesvirus 6 and/or 7 (HHV-6/7) have recently attracted attention as microbiological markers of physiological fatigue in laborers and athletes. However, the accuracy and efficiency of the HHV-6/7 assays can be improved for practical application. We conducted three experiments to identify suitable saliva collection and DNA extraction methods for practical salivary HHV-6/7 assays. The main experiment compared the data, including template DNA or HHV-6/7 concentrations, among three saliva collection methods (cotton, synthetic, and no swabs) and two DNA extraction methods (magnetic bead-based and silica column-based). It showed that using swabs had adverse effects: lower template DNA concentration, lower HHV-6/7 detection rates, higher coefficient of variation values, and lower concentrations. Moreover, magnetic bead-based methods resulted in higher HHV-6/7 detection rates and lower coefficient of variation values. Sub-experiment 1 examined practical saliva collection methods and demonstrated that the stimulated spitting method could collect saliva in a shorter time with lower subjective stress than the unstimulated spitting and stimulated swabbing methods. Sub-experiment 2 investigated diurnal variation in salivary HHV-6/7 levels but did not show diurnal variation. These findings suggest that (1) the combination of stimulated spitting saliva collection and magnetic bead-based DNA extraction is most suitable for practical salivary HHV-6/7 assays, and (2) saliva collection can be conducted whenever needed.

Salivary Proteome Insights: Evaluation of Saliva Preparation Methods in Mucopolysaccharidoses Research

Background: This research aimed to compare the traditional in-solution digestion (inSol) and solid-phase-enhanced sample preparation (SP3) methods for salivary proteomics, with a focus on identifying mucopolysaccharidosis (MPS)-relevant proteins. Methods: Saliva samples were processed under multiple analytical conditions, including two precipitation methods (methanol or incubation with trichloroacetic acid), paired with either Rapigest or 8M urea/2M thiourea (UT) solubilization buffers. Additionally, the SP3 method was directly applied to raw saliva without pre-processing. Proteome coverage, reproducibility, digestion efficiency, and gene function were assessed. Results: The inSol method consistently provided superior proteome coverage, with trichloroacetic acid precipitation and Rapigest buffer yielding 74 MPS-relevant proteins, compared to 40 with SP3 MeOH UT. Both methods showed high digestion efficiency, particularly with Rapigest buffer, achieving over 80% full cleavage across conditions. Functional analysis revealed broad similarities, with protocol-specific impacts on protein classes and cellular components. Conclusions: This study is the first to compare SP3 and in-solution digestion for salivary proteomics, emphasizing the importance of method selection to address matrix-specific challenges. The results highlight the robustness of inSol for comprehensive proteome profiling and SP3's potential for streamlined clinical workflows, offering valuable insights into optimizing salivary proteomics for biomarker discovery in MPS and other diseases.

Safety of oral mucosal punch biopsy and other oral biospecimen collections in clinical research

OBJECTIVE

Oral punch biopsies are frequently used for analysis of lesions since they are minimally invasive, easily performed, and assist in diagnosis. Despite broad usage, recent changes in risk classification characterize oral punch biopsies as "greater than minimal risk" for institutional review board purposes. We performed a retrospective review of oral sampling in clinical trials to determine the safety of punch biopsies and other biospecimen collection methods in our oral cancer surveillance program.

STUDY DESIGN

Punch biopsies of 3- and 4-mm were collected following topical and local injection anesthetic. Hemostasis was achieved using pressure and silver nitrate cautery. Other specimens were collected according to standard collection guidelines. Safety and adverse events were determined through consultation with clinical investigator guidelines and were graded with the NCI Common Terminology Criteria for Adverse Events (CTCAE) v5.

RESULTS

In total, 579 samples were collected, 339 of which were oral punch biopsies. There were no adverse events above NCI CTCAE grade 1 for any biospecimen collection.

CONCLUSIONS

These results support the safety profile of oral punch biopsies and saliva collection. Additionally, these results align with previous research on punch biopsy safety and demonstrate fewer bleeding events. Based on the results and prior research, we believe that punch biopsies should be considered a minimal-risk procedure.

Clinical research for saliva-based therapeutic drug monitoring of linezolid

AIMS

Linezolid is primarily used to treat of methicillin-resistant Staphylococcus aureus and multidrug-resistant tuberculosis infections. Thrombocytopenia due to linezolid usage is a concern, and therapeutic drug monitoring has been reported to be effective in its prevention. Plasma concentrations provide valuable information for treatment decisions; however, collecting plasma samples can be burdensome for both patients and healthcare providers. Therefore, there is interest in saliva as an alternative for monitoring, considering its potential to replace plasma samples.

METHODS

Patients hospitalized at Hokkaido University Hospital and Hokkaido Spinal Cord Injury Center between April 2022 and July 2024, who received oral or intravenous linezolid treatment, were enrolled. The concentrations of linezolid were simultaneously measured in plasma and saliva samples. We determined the concentration profiles of linezolid in the saliva and examined the correlation between saliva and plasma linezolid concentrations.

RESULTS

Eighteen patients receiving linezolid were enrolled. The average of saliva/plasma (S/P) concentration ratios of linezolid were 1.018. A strong correlation was found between the salivary and plasma concentrations of linezolid (R = .833, P < .001). Notably, in patients receiving intravenous administration of linezolid, the correlation was even more pronounced (R = .885, P < .001). Additionally, when focusing on the S/P ratio of the trough concentrations in the morning and at night, the S/P ratios at night were much closer to 1.0.

CONCLUSION

The concentrations of linezolid in plasma and saliva were similar, indicating their potential applicability in clinical settings. The monitoring of linezolid concentrations in saliva has been shown to be particularly suitable for patients receiving intravenous administration.

Investigating the psychophysiological effects of NaiKan Therapy: salivary oxytocin and cortisol release

NaiKan Therapy, a method of self-reflection and introspection, has garnered considerable interest for its psychological benefits. However, its physiological impacts, particularly on hormonal regulation, remain underexplored. In this study, we aimed to investigate the effects of NaiKan Therapy on salivary oxytocin and cortisol release, shedding light on the psychophysiological mechanisms underlying this introspective practice. Sixty participants underwent Naikan Therapy sessions over five consecutive days, during which salivary samples were collected at multiple time points. Salivary oxytocin and cortisol levels were measured using enzyme-linked immunosorbent assay (ELISA) kits. Our results revealed significant increases in salivary oxytocin levels following NaiKan Therapy, suggesting a potential role of this practice in enhancing social bonding and emotional regulation. Conversely, salivary cortisol levels exhibited a decrease post-therapy, indicating a reduction in stress reactivity. These findings provide novel insights into the neuroendocrine mechanisms underlying NaiKan Therapy and highlight its potential as a holistic approach to improving mental wellbeing. Further research exploring the long-term effects of NaiKan Therapy and its implications for clinical practice is warranted.

Salivary microbiota characterization of Yerba Mate consumers in Uruguay

INTRODUCTION

Yerba Mate (YM) is a green-colored infusion, derived from the Ilex paraguariensis plant, very popular and commonly consumed in Latin American countries (southern Brazil, Argentina, Paraguay, and Uruguay), rapidly gaining penetration in global markets, It's a beverage rich in polyphenols, alkaloids, and saponins, making its impact on the oral microbiome particularly interesting.

OBJECTIVES

This study aimed to characterize the composition of salivary microbiota in Uruguayan YM consumers and non-consumers, exploring potential implications for oral health.

MATERIALS AND METHODS

Salivary samples were collected from 24 YM consumers and 28 non-consumers in Uruguay (n = 52). Participants were dentistry students, aged 18 to 35, with no reported pathologies and who had no oral conditions after visual inspection. 16S rRNA gene metabarcoding Illumina sequencing was employed to analyze their microbial composition. Bioinformatic analysis was conducted to identify and compare microbial taxa between the two groups. Relevant demographic and dietary data were also collected and analyzed.

RESULTS

The salivary microbiome of YM consumers is not completely different from non-consumers, however, several particular characteristics were found in each group. Both YM consumers and non-consumers exhibited a high relative abundance of Streptococcus species, with Streptococcus oralis being more abundant in a subset of non-consumers suggesting that YM may help maintain a balanced oral microbiota. Although no significant differences were observed in the Shannon diversity index, YM consumers might have a more diverse microbiome than non-consumers (YM consumers showed significantly higher species richness (Chao1 index), a greater number of amplicon sequence variants (ASVs), and broader microbial diversity, as confirmed by multivariate analyses). While the presence of Prevotella spp. in YM consumers aligns with previous research on polyphenol-rich beverages, its role in oral health warrants further investigation.

CONCLUSIONS

This study highlights the influence of YM consumption on salivary microbiota composition and diversity. YM consumption was associated with increased microbial diversity and species richness, which may contribute to oral microbiome resilience and health. These findings underscore the impact of dietary habits on oral microbial communities and their potential implications for oral health management and disease prevention.

Photothermal Desorption and Reagent-Assisted Low-Temperature Plasma Ionization Miniature IT-MS/MS for On-Site Analysis of Illicit Drugs in Saliva and Urine

Globally, drug-impaired driving fatalities now exceed those from drunk driving, urging the need for on-site and roadside detection methods. In this study, a photothermal desorption and reagent-assisted low-temperature plasma ionization miniature ion trap mass spectrometer (PDRA-LTP-ITMS) was developed for on-site detection of drug-impaired driving. The pseudomultiple reaction monitoring (MRM) in PDRA-LTP-ITMS enables continuous ion selection during ion introduction and improved sensitivity to nearly 3-fold compared with the conventional full scan mode. The PDRA-LTP integrated the ionization source and photothermal desorption region into the LTP tube with a volume of 0.05 mL. Photoionization and Penning ionization from LTP discharging facilitate proton transfer reactions with the dopant and produce characteristic [M + H]+ for drugs. Dopants of butanol and acetone were separately employed to enhance the thermal desorption and ionization efficiency, resulting in a 2.6-fold sensitivity increase. Saliva and urine samples were collected with a medical swab, and only 10 μL of sample is required for each analysis. The sample is rapidly heated to 250 °C using a halogen lamp and analyzed within 5 s. With these designs, a 4-fold and 10-fold increase in sensitivity was achieved compared to APPI and nano-ESI, respectively. The limits of detection (S/N = 3) of illicit drugs, including MDMA, MDA, methamphetamine, amphetamine, ketamine, and cocaine, in saliva ranged from 4.5 pg μL -1 to 20 pg μL-1 and met the threshold values of GA1333-2017. The performance of the PDRA-LTP-ITMS was even comparable to that of LTQ-Orbitrap Velos Pro ETD MS, providing a novel method of rapid on-site drug-impaired driving analysis.

Assessment of oral health-related quality of life and oral side effects of radioactive iodine therapy

OBJECTIVES

To evaluate the impact of oral health problems on oral health-related quality of life (OHRQoL) among female patients received Radioactive iodine (131I) therapy.

MATERIALS AND METHODS

This unmatched case-control study was conducted on 40 female patients (20 cancer free controls and 20 patients treated with 131I therapy). Data were collected via clinical examination, self reported questionnaire including the Oral Health Impact Profile-14 (OHIP-14), salivary tests, socio-demographic and behavioural characteristics. Data were analyzed using descriptive, bivariate and multivariate statistics.

RESULTS

There were significant differences in the total number of decayed, missing and filled surfaces, stimulated and unstimulated salivary flow rates, and periodontal indices between the study and control groups in the unadjusted analysis. Age adjusted analysis revealed significant differences in the stimulated and unstimulated salivary flow rates, periodontal indices, physical pain domain scores between groups. No significant differences were observed between groups in the xerostomia severity and OHRQoL. In study group, the score for the OHIP-14 psychological discomfort domain was negatively correlated with both stimulated and unstimulated salivary flow rates. The total OHIP-14 score and its domain scores of physical pain and psychological disability were correlated positively with the severity of xerostomia, but negatively correlated with number of the repeated 131I therapy.

CONCLUSIONS

Due to xerostomia, patients reported worse OHRQoL in the domains of physical pain, psychological discomfort and disability. They had worse periodontal status and tooth brushing habits than healthy controls.

CLINICAL RELEVANCE

The findings of this study may provide a valuable insight on the oral health problems and needs of target group when planning a a team-based care.

Saliva assay: a call for methodological standardization

The oral cavity provides an ideal environment for microorganisms, including bacteria, viruses, and fungi, to flourish. Increasing attention has been focused on the connection between the oral microbiome and both oral and systemic diseases, spurring active research into the collection and analysis of specimens for healthcare purposes. Among the various methods for analyzing the oral microbiome, saliva analysis is especially prominent. Saliva samples, which can be collected non-invasively, provide information on the systemic health and oral microbiome composition of an individual. This review was performed to evaluate the current state of the relevant research through an examination of the literature and to suggest an appropriate assay method for investigating the oral microbiome. We analyzed articles published in English in SCI(E) journals after January 1, 2000, ultimately selecting 53 articles for review. Articles were identified through keyword searches in the PubMed, Embase, Cochrane, Web of Science, and CINAHL databases. Three experienced researchers conducted full-text assessments following title and abstract screening to select appropriate papers. Subsequently, they organized and analyzed the desired data. Our review revealed that most studies utilized unstimulated saliva samples for oral microbiome analysis. Of the 53 studies examined, 29 identified relationships between the oral microbiome and various diseases, such as oral disease, Behçet disease, cancer, and oral lichen planus. However, the studies employed diverse methods of collection and analysis, which compromised the reliability and accuracy of the findings. To address the limitations caused by methodological inconsistencies, a standardized saliva assay should be established.

Measuring salivary cortisol in biobehavioral research: A systematic review and methodological considerations

The assessment of salivary cortisol in community settings has gained popularity in biobehavioral research due to its noninvasive sampling, ease of handling and storage, and suitability for repeated sampling in short intervals. Ensuring consistent methodological practices for salivary cortisol is essential. This systematic review critically examines salivary cortisol collection procedures, data cleaning, and analysis to better understand its role in biobehavioral research within community populations. Fifty-eight articles met the inclusion criteria. Results indicated significant variability in study designs and cortisol measurement procedures, particularly regarding the biobehavioral role of cortisol, sampling periods, covariate considerations, cortisol analysis parameters, and data analysis plans. The review highlights commonly used and promising study designs while identifying methodological issues in cortisol measurement and analysis that should be addressed to improve comparability in future research.

Reusable Biosensor for Easy RNA Detection from Unfiltered Saliva

Biosensors are transforming point-of-care diagnostics by simplifying the detection process and enabling rapid, accurate testing. This study introduces a novel, reusable biosensor designed for direct viral RNA detection from unfiltered saliva, targeting SARS-CoV-2. Unlike conventional methods requiring filtration, our biosensor leverages a unique electrode design that prevents interference from saliva debris, allowing precise measurements. The biosensor is based on electrochemical principles, employing oligonucleotide probes immobilized on a hydrophobic-coated electrode, which prevents air bubbles and salt crystal formation. During validation, the biosensor demonstrated a sensitivity and specificity of 100%, accurately identifying SARS-CoV-2 in saliva samples without false positives or negatives. Cross-validation with RT-qPCR, the gold standard for COVID-19 diagnostics, confirmed the reliability of our device. The biosensor's performance was tested on 60 participants, yielding 12 true positive results and 48 true negatives, aligning perfectly with RT-qPCR outcomes. This reusable, easy-to-use biosensor offers significant potential for point-of-care applications in various healthcare settings, providing a fast, efficient, and cost-effective method for detecting viral infections such as COVID-19. Its robust design, minimal sample preparation requirements, and multiple-use capability mark a significant advancement in biosensing technology.

Performance of a Point-of-Care Test Kit (Anigen Rapid®) to Diagnose Feline Immunodeficiency Virus (FIV) Infection in Domestic Cats Using Saliva Instead of Blood in Australia

The primary aim of this study was to determine the accuracy of saliva as a proxy for blood in cats using Anigen Rapid® FIV point-of-care (PoC) kits and as an easy collection technique applicable for all veterinary clinics and shelters. A secondary aim was to report FIV prevalence in various Australian states/territories and key cat risk factors associated with FIV infection. In total, 382 cats were recruited from patients presenting to private, shelter and teaching hospital veterinary clinics in Australia. Information collected for each cat included age, sex, neuter status, postcode, and health status ('healthy' versus 'sick'). The traditional blood testing technique with Anigen Rapid® was used to determine the FIV status of cats. Comparative saliva testing found 48/382 (12.5%) cats were FIV-positive. Test sensitivity for Anigen Rapid® FIV using saliva was 84.2% (48/57; 95% CI 80.6 to 87.9). Test specificity for Anigen Rapid® FIV using saliva was 100% (325/325). The two significant cat risk factors for FIV infection were sex (male) and health status (sick). In terms of demographic information, prevalence in Tasmania and the Northen Territory was reported for the first time. This study proves the ability to utilise cheap and readily available consumables for less invasive FIV testing purposes by using saliva instead of blood, for example, when screening cat before adoption in shelters and in cats prior to annual FIV re-vaccination.

Hair and Saliva Endocannabinoid and Steroid Hormone Analysis by Liquid Chromatography Paired with Tandem Mass Spectrometry

Endocannabinoids are lipid neurotransmitters that play an important part in human health. Recent methods have found that quantification of endocannabinoids in hair and saliva samples is possible using liquid chromatography paired with tandem mass spectrometry (LC-MS/MS). This chapter describes two simple sample preparation methods that can be used to prepare hair and saliva samples for analysis using LC-MS/MS. Our LC-MS/MS method can be applied to both hair and saliva samples and is sufficiently sensitive for endocannabinoid, as well as steroid hormone, quantification in both of these sample matrices. This chapter provides a comprehensive description of how this can be achieved and provides tips and tricks for troubleshooting problems users may experience.

Reliability of roadside oral fluid testing devices for ∆9-tetrahydrocannabinol (∆9-THC) detection

Driving under the influence of cannabis (DUIC) is increasing worldwide, and cannabis is the most prevalent drug after alcohol in impaired driving cases, emphasizing the need for a reliable traffic enforcement strategy. ∆9-tetrahydrocannabinol (THC) detection in oral fluid has great potential for identifying recent cannabis use; however, additional data are needed on the sensitivities, specificities, and efficiencies of different oral fluid devices for detecting cannabinoids at the roadside by police during routine traffic safety enforcement efforts. At the roadside, 8945 oral fluid THC screening tests were performed with four devices: AquilaScan®, Dräger DrugTest®, WipeAlyser Reader®, and Druglizer®. A total of 530 samples screened positive for THC (5.9%) and were analyzed by liquid chromatography-tandem mass spectrometry at multiple cutoff concentrations (2 ng/mL, 10 ng/mL, and manufacturers' recommended device cutoffs) to investigate device performance. Results varied substantially, with sensitivities of 0%-96.8%, specificities of 89.8%-98.5%, and efficiencies of 84.3%-97.8%. The Dräger DrugTest® outperformed the other devices with a 96.8% sensitivity, 97.1% specificity, and 97.0% efficiency at a 5-ng/mL LC-MS/MS confirmation cutoff. The WipeAlyser Reader® had good performance with a 91.4% sensitivity, 97.2% specificity, and 96.4% efficiency. AquilaScan® and Druglizer® had unacceptable performance for cannabinoid detection, highlighted by sensitivity <13%. The choice of roadside oral fluid testing device must offer good analytical performance for cannabinoids because of its high prevalence of use and impact on road safety.

Applied body-fluid analysis by wearable devices

Wearable sensors are a recent paradigm in healthcare, enabling continuous, decentralized, and non- or minimally invasive monitoring of health and disease. Continuous measurements yield information-rich time series of physiological data that are holistic and clinically meaningful. Although most wearable sensors were initially restricted to biophysical measurements, the next generation of wearable devices is now emerging that enable biochemical monitoring of both small and large molecules in a variety of body fluids, such as sweat, breath, saliva, tears and interstitial fluid. Rapidly evolving data analysis and decision-making technologies through artificial intelligence has accelerated the application of wearables around the world. Although recent pilot trials have demonstrated the clinical applicability of these wearable devices, their widespread adoption will require large-scale validation across various conditions, ethical consideration and sociocultural acceptance. Successful translation of wearable devices from laboratory prototypes into clinical tools will further require a comprehensive transitional environment involving all stakeholders. The wearable device platforms must gain acceptance among different user groups, add clinical value for various medical indications, be eligible for reimbursements and contribute to public health initiatives. In this Perspective, we review state-of-the-art wearable devices for body-fluid analysis and their translation into clinical applications, and provide insight into their clinical purpose.

A 96-position platform for magnetic sorbent-based dispersive microextraction: Application to the determination of tetrahydrocannabinol and cannabidiol in saliva of cannabis smokers

BACKGROUND

In order to obtain sustainable analytical methods, it is essential to develop kinetically efficient sample preparation strategies in which equilibria are reached faster, as dispersive extraction techniques. In addition, the higher the reduction in size, the higher number of extraction vessels can be located and thus the higher number of samples can be simultaneously treated. All this increases sample throughput, and contributes to the reduction of chemical waste, and energy and sample consumption. In this sense, multiposition extraction platforms are smart strategies to achieve these goals, but they are scarcely developed for dispersive extraction techniques.

RESULTS

Taking miniaturized stir bar sorptive dispersive microextraction (mSBSDME) as a starting point, a 96-position extraction platform has been developed using a 96-position stirring plate and a tailor-designed 3D-printed support for locating the miniaturized extraction vessels, achieving a high-throughput miniaturized sample preparation strategy. In order to show the applicability of this novel platform, the determination of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in human saliva has been carried out and applied to samples collected after the consumption of marijuana and legal CBD-rich cannabis. Only 100 μL of saliva were needed for the analysis and good analytical features in terms of linearity (at least up to 500 ng mL-1), limits of detection (0.7 and 2.8 ng mL-1 for THC and CBD, respectively), and precision (RSD ≤ 14 %) were achieved.

SIGNIFICANCE

The miniaturization of the vessel allows the use of small volumes of sample (i.e., a few microliters) and the treatment of 96 samples in parallel, being the first proposal for carrying out dispersive sorbent-based microextraction under the concept of 96-well format. Additionally, this new workflow contributes to the development of analytical methods that meet the three pillars of sustainability, i.e., greenness and easily affordable in terms of economics and applicability.

The LOD paradox: When lower isn't always better in biosensor research and development

Biosensor research has long focused on achieving the lowest possible Limits of Detection (LOD), driving significant advances in sensitivity and opening up new possibilities in analysis. However, this intense focus on low LODs may not always meet the practical needs or suit the actual uses of these devices. While technological improvements are impressive, they can sometimes overlook important factors such as detection range, ease of use, and market readiness, which are vital for biosensors to be effective in real-world applications. This review advocates for a balanced approach to biosensor development, emphasizing the need to align technological advancements with practical utility. We delve into various applications, including the detection of cancer biomarkers, pathology-related biomarkers, and illicit drugs, illustrating the critical role of LOD within these contexts. By considering clinical needs and broader design aspects like cost-effectiveness, sustainability, and regulatory compliance, we argue that integrating technical progress with practicality will enhance the impact of biosensors. Such an approach ensures that biosensors are not only technically sound but also widely useable and beneficial in real-world applications. Addressing the diverse analytical parameters alongside user expectations and market demands will likely maximize the real-world impact of biosensors.

Optimization of saliva sampling methods for analysis of bile acids by UHPLC-MS

This study investigated methods for sampling bile acids in saliva, a potential non-invasive diagnostic biofluid. Bile acids have been implicated in causing damage and permanent changes to the esophageal mucosa and increasing the risk of developing Barrett's esophagus, a condition that can potentially progress to esophageal cancer. Three saliva collection methods were compared: spitting, Salivette® swabs, and Salivette Cortisol® swabs. Spitting emerged as the superior method with the highest recoveries and the least interference, likely due to Salivette swabs retaining bile acids or introducing unknown interferences. All saliva samples were analyzed by UHPLC-MS/MS using the Zorbax RRHD Eclipse Plus C18 column (3 × 50 mm, 1.8 µm) in gradient elution of 0.1 % formic acid in water and methanol. Saliva sample stability was assessed over 14 days, reflecting typical storage times. The levels of detected bile acids were stable for the measured period (RSD ≤ 22 %) and no degradation was observed. Bile acid levels in saliva fluctuated throughout the day, with the greatest changes observed for glycine-conjugated bile acids after meals. To minimize sampling variability, saliva collection by spitting after overnight fasting is recommended for future studies. Our findings are applicable for standardized bile acid sampling and are currently applied in a large clinical study evaluating bile acids as potential susceptibility markers for Barrett's esophagus diagnostics.

Salivaomics: A Revolutionary Non-invasive Approach for Oral Cancer Detection

Salivaomics has emerged as a ground-breaking field in the detection and management of oral cancer (OC), offering a non-invasive, efficient, and patient-friendly alternative to traditional diagnostic methods. This innovative approach leverages the comprehensive molecular insights provided by genomics, transcriptomics, proteomics, metabolomics, and microbiomics. The potential of salivaomics lies in its ability to enable early detection, predict malignant transformation, and monitor treatment outcomes and disease recurrence. Advancing salivary diagnostics necessitates the standardization of saliva collection and processing protocols, identification and validation of robust biomarkers, and development of cutting-edge detection technologies. A single biomarker is unlikely to fulfill all diagnostic requirements; thus, research should focus on developing a panel of biomolecules to enhance diagnostic accuracy and management of OC. Salivaomics stands at the forefront of non-invasive diagnostic methods, with the promise to revolutionize early detection and management of OC. Future research directions should emphasize the integration of multi-omics data for superior biomarker discovery, the development of portable and cost-effective point-of-care devices, and the fostering of interdisciplinary collaborations to drive innovation. Overcoming these challenges will facilitate the translation of salivaomics into routine clinical practice, significantly improving early diagnosis, treatment, and prognosis of OC. This review provides a comprehensive overview of salivaomics, detailing the use of saliva as a diagnostic fluid. It covers saliva collection, preparation, transportation, storage methods, and various analytical techniques. Additionally, the review discusses the current challenges and future directions of this transformative technology, emphasizing its potential to enhance clinical outcomes in OC.

The human volatilome meets cancer diagnostics: past, present, and future of noninvasive applications

BACKGROUND

Cancer is a significant public health problem, causing dozens of millions of deaths annually. New cancer screening programs are urgently needed for early cancer detection, as this approach can improve treatment outcomes and increase patient survival. The search for affordable, noninvasive, and highly accurate cancer detection methods revealed a valuable source of tumor-derived metabolites in the human metabolome through the exploration of volatile organic compounds (VOCs) in noninvasive biofluids.

AIM OF REVIEW

This review discusses volatilomics-based approaches for cancer detection using noninvasive biomatrices (breath, saliva, skin secretions, urine, feces, and earwax). We presented the historical background, the latest approaches, and the required stages for clinical validation of volatilomics-based methods, which are still lacking in terms of making noninvasive methods available and widespread to the population. Furthermore, insights into the usefulness and challenges of volatilomics in clinical implementation steps for each biofluid are highlighted.

KEY SCIENTIFIC CONCEPTS OF REVIEW

We outline the methodologies for using noninvasive biomatrices with up-and-coming clinical applications in cancer diagnostics. Several challenges and advantages associated with the use of each biomatrix are discussed, aiming at encouraging the scientific community to strengthen efforts toward the necessary steps to speed up the clinical translation of volatile-based cancer detection methods, as well as discussing in favor of (i) hybrid applications (i.e., using more than one biomatrix) to describe metabolite modulations that can be "cancer volatile fingerprints" and (ii) in multi-omics approaches integrating genomics, transcriptomics, and proteomics into the volatilomic data, which might be a breakthrough for diagnostic purposes, onco-pathway assessment, and biomarker validations.

Association between calcium-channel blockers and gingival enlargement: A case-control study

OBJECTIVES

As reported by the existing literature, calcium-channel blockers (CCB) can lead to gingival enlargement. The aims of this study were to investigate the factors associated with gingival enlargement in patients on CCB and to assess the saliva and gingival crevicular fluid (GCF) profile of patients on CCB with gingival enlargement.

METHODS

A total of 131 participants were included. Data were collected from 91 patients taking CCB for treatment of systemic hypertension. The presence of drug-induced gingival enlargement (DIGE) was assessed clinically and associated with patient factors. Patients with DIGE were group-matched for gender and ethnicity with an equal number of consecutive CCB non-DIGE patients (control 1), no-CCB no-DIGE (control 2) and periodontally healthy with no DIGE (control 3) for the saliva and GCF analysis. A bead-based multiplex immunoassay was used to assess a panel of biomarkers.

RESULTS

Twenty-two percent of patients on CCB were diagnosed with DIGE. Lack of daily interdental cleaning and self-reported diagnosis of type II diabetes were associated with the diagnosis of DIGE. When analysing patients only on CCB, those with DIGE had higher GCF levels of vascular endolthelial growth factor (VEGF) (p = 0.032), epidermal growth factor (EGF) (p = 0.030) and matrix metalloproteinase-8 (MMP-8) (p = 0.008). Among the salivary markers, only MMP-8 showed a statistically significant difference across groups (p < 0.001).

CONCLUSIONS

This is the first study investigating saliva and GCF biomarkers in patients with DIGE and different control groups, suggesting that causes of the overgrowth might involve inflammatory processes, tissue damage pathways, and potentially an impact on growth factors like VEGF. Future research should verify these results in independent populations and explore the underlying pathogenic mechanisms in-depth.

CLINICAL SIGNIFICANCE

Calcium-channel blockers (CCB) can lead to gingival enlargement. This study confirms lack of interdental cleaning and type II diabetes as risk factors. Elevated levels of VEGF, EGF, and MMP-8 in gingival crevicular fluid and MMP-8 in saliva suggest inflammatory processes and growth factors might play roles in this condition.

Oral and Gingival Crevicular Fluid Biomarkers for Jawbone Turnover Diseases: A Scoping Review

Gingival crevicular fluid (GCF) and oral fluid have emerged as promising diagnostic tools for detecting biomarkers. This review aimed to evaluate the existing literature on using oral fluids as a source of biomarkers for bone turnover diseases affecting the jawbone. A comprehensive search strategy was executed between August 2014 and August 2024 across five major databases (Web of Science, EBSCOhost Dentistry & Oral Sciences Source, Cochrane Library, Scopus, and PubMed) and grey literature sources. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) was applied. The screening was facilitated using Rayyan at rayyan.ai and Endnote X20 software tools, culminating in the evaluation of 14,965 citations from databases and 34 from grey literature. Following rigorous scrutiny, 37 articles were selected for inclusion in this review, encompassing diseases such as periodontitis, medication-related osteonecrosis of the jaw (MRONJ), and osteoporosis. The quality of the included observational studies was assessed using the Revised Risk of Bias Assessment Tool for Non-Randomized Studies (RoBANS 2). Interleukin-1 beta (IL-1β), sclerostin, osteoprotegerin (OPG), and interleukin-34 (IL-34) emerged as significant biomarkers in GCF, and they were mainly from periodontitis and osteoporosis. Osteocalcin (OC), IL-1β, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), OPG, and matrix metalloproteinase-9 (MMP-9) were significant in oral fluid or saliva, and they were from periodontitis, MRONJ, and osteoporosis. These findings underscore the potential use of oral fluids, which are regarded as non-invasive tools for biomarker identification in bone turnover. Many biomarkers overlap, and it is important to identify other specific biomarkers to enable accurate diagnosis of these conditions.

Oxytocin Receptor Single-Nucleotide Polymorphisms Are Related to Maternal-Infant Co-Occupation and Infant Sensory Processing

BACKGROUND

Caregiver-infant reciprocity is related to infant/toddler development and health. However, there is a dearth of research on reciprocity variables like co-occupation and developmental variables such as infant/toddler sensory processing/preferences, and it is important to understand the biopsychosocial mediators of these relations. These include novel genetic markers like maternal oxytocin receptor single-nucleotide polymorphisms (OXTR SNPs). Therefore, this study examined whether mothers carrying risk alleles for three OXTR SNPs displayed different co-occupational behaviors with their infants and whether their infants/toddlers showed different sensory processing/preferences.

METHODS

Data from the Infant Development and Healthy Outcomes in Mothers Study included prenatal saliva samples assayed for OXTR SNPs, 6-month postnatal behavioral observations coded for maternal-infant co-occupations (reciprocal emotionality, physicality, and intentionality), and 10-, 14-, and 18-month postnatal, maternal-reported Infant/Toddler Sensory Profiles (classified as within or outside the majority range for low registration, sensory seeking, sensory sensitivity, and sensory avoiding).

RESULTS

Mothers with rs53576 risk allele A engaged in more frequent reciprocal emotionality, while those with rs2254298 risk allele A engaged in less frequent reciprocal emotionality but more frequent reciprocal intentionality. Mothers with rs53576 risk allele A had infants with 11 times greater odds of being outside of the majority range for sensation avoiding at 10 months old.

CONCLUSIONS

The results converge with the literature supporting links between OXTR SNPs, caregiver reciprocity, and infant/toddler development but extend the findings to relatively novel constructs (caregiver-infant co-occupations and infant/toddler sensory processing/preferences).

Capture of Group A Streptococcus by Open-Microfluidic CandyCollect Device in Pediatric Patients

State the purpose

Obtaining high-quality samples to diagnose streptococcal pharyngitis in pediatric patients is challenging due to discomfort associated with traditional pharyngeal swabs. This may cause reluctance to go to the clinic, inaccurate diagnosis, or inappropriate treatment for children with sore throat. Here, we determined the efficacy of CandyCollect, a lollipop-inspired open-microfluidic pathogen collection device, to capture Group A Streptococcus (GAS) and compare user preference for CandyCollect, conventional pharyngeal swabs, or mouth swabs in children with pharyngitis and their caregivers.

Results

All child participants (30/30) were positive for GAS by qPCR on both the mouth swab and CandyCollect. Caregivers ranked CandyCollect as a good sampling method overall (27/30), and all caregivers (30/30) would recommend CandyCollect for children 5 years and older. Twenty-three of 30 children "really like" the taste and 24/30 would prefer to use CandyCollect if a future test were needed. All caregivers (30/30) and most children (28/30) would be willing to use CandyCollect at home.

Conclusion

All participants tested positive for GAS on all three collection methods (pharyngeal swab, mouth swab, and CandyCollect). While both caregivers and children like CandyCollect, some caregivers would prefer a shorter collection time. Future work includes additional studies with larger cohorts presenting with pharyngitis of unknown etiology and shortening collection time while maintaining the attractive form of the device.

Translational Impact Statement

Obtaining oral samples for the diagnosis of streptococcal pharyngitis is of great importance for children. To address the challenges associated with traditional pharyngeal swab sampling, we developed the CandyCollect device, a lollipop-inspired open mesofluidic saliva sampling system. In this study, saliva samples were collected from children, aged 5-14 years, with CandyCollect and mouth swabs and analyzed via qPCR. The results show CandyCollect is the child preferred collection tool and had 100% concordance with the results from traditional diagnosis methods as part of their clinical care.

Integration of a Cas12a-mediated DNAzyme actuator with efficient RNA extraction for ultrasensitive colorimetric detection of viral RNA

Developing highly sensitive and specific on-site tests is imperative to strengthen preparedness against future emerging infectious diseases. Here, we describe the construction of a Cas12a-mediated DNAzyme actuator capable of converting the recognition of a specific DNA sequence into an amplified colorimetric signal. To address viral RNA extraction challenges for on-site applications, we developed a rapid and efficient method capable of lysing the viral particles, preserving the released viral RNA, and concentrating the viral RNA. Integration of the DNAzyme actuator with the viral RNA extraction method and loop-mediated isothermal amplification enables a streamlined colorimetric assay for highly sensitive colorimetric detection of respiratory RNA viruses in gargle and saliva. This assay can detect as few as 83 viral particles/100 μL in gargle and 166 viral particles/100 μL in saliva. The entire assay, from sample processing to visual detection, was completed within 1 h at a single controlled temperature. We validated the assay by detecting SARS-CoV-2 in 207 gargle and saliva samples, achieving a clinical sensitivity of 96.3 % and specificity of 100%. The assay is adaptable for detecting specific nucleic acid sequences in other pathogens and is suitable for resource-limited settings.

The future backbone of nutritional science: integrating public health priorities with system-oriented precision nutrition

Adopting policies that promote health for the entire biosphere (One Health) requires human societies to transition towards a more sustainable food supply as well as to deepen the understanding of the metabolic and health effects of evolving food habits. At the same time, life sciences are experiencing rapid and groundbreaking technological developments, in particular in laboratory analytics and biocomputing, placing nutrition research in an unprecedented position to produce knowledge that can be translated into practice in line with One Health policies. In this dynamic context, nutrition research needs to be strategically organised to respond to these societal expectations. One key element of this strategy is to integrate precision nutrition into epidemiological research. This position article therefore reviews the recent developments in nutrition research and proposes how they could be integrated into cohort studies, with a focus on the Swiss research landscape specifically.

Ion-sensitive field effect transistor biosensors for biomarker detection: current progress and challenges

The ion-sensitive field effect transistor (ISFET) has emerged as a crucial sensor device, owing to its numerous benefits such as label-free operation, miniaturization, high sensitivity, and rapid response time. Currently, ISFET technology excels in detecting ions, nucleic acids, proteins, and cellular components, with widespread applications in early disease screening, condition monitoring, and drug analysis. Recent advancements in sensing techniques, coupled with breakthroughs in nanomaterials and microelectronics, have significantly improved sensor performance. These developments are steering ISFETs toward a promising future characterized by enhanced sensitivity, seamless integration, and multifaceted detection capabilities. This review explores the structure and operational principles of ISFETs, highlighting recent research in ISFET biosensors for biomarker detection. It also examines the limitations of these sensors, proposes potential solutions, and anticipates their future trajectory. This review aims to provide a valuable reference for advancing ISFETs in the field of biomarker measurement.

Lab-on-a-lollipop (LoL) platform for preventing food-induced toxicity: all-in-one system for saliva sampling and electrochemical detection of vanillin

Saliva has emerged as a primary biofluid for non-invasive disease diagnostics. Saliva collection involves using kits where individuals stimulate saliva production via a chewing device like a straw, then deposit the saliva into a designated collection tube. This process may pose discomfort to patients due to the necessity of producing large volumes of saliva and transferring it to the collection vessel. This work has developed a saliva collection and analysis device where the patient operates it like a lollipop, stimulating saliva production. The lollipop-mimic device contains yarn-based microfluidic channels that sample saliva and transfer it to the sensing zone embedded in the stem of the device. We have embedded electrochemical sensors in the lollipop platform to measure vanillin levels in saliva. Vanillin is the most common food flavoring additive and is added to most desserts such as ice cream, cakes, and cookies. Overconsumption of vanillin can cause side effects such as muscle weakness, and damage to the liver, kidneys, stomach, and lungs. We detected vanillin using direct oxidation at a laser-induced graphene (LIG) electrode. We showed a dynamic range of 2.5 μM to 30 μM, covering the physiologically relevant concentration of vanillin in saliva. The lab-on-a-lollipop platform requires only 200 μL of saliva and less than 2 minutes to fill the channels and complete the measurement. This work introduces the first sensor-embedded lollipop-mimic saliva collection and measurement system.

Untargeted stimulated and unstimulated salivary metabolomics and saliva flow rate in children

OBJECTIVE

The present study aimed to determine the salivary flow and metabolomic profile of stimulated and unstimulated saliva in children.

MATERIALS AND METHODS

Children who attended the Pediatric Dentistry Clinic of the State University of Rio de Janeiro -UERJ between 3 and 12 years of age were selected. Unstimulated and stimulated whole saliva, using mechanical stimulus, were collected. The samples were centrifuged at 12,000 g, 4oC for 1 h. The 1H- NMR spectra were acquired in 500 MHz equipment. The data were extracted into 0.03 ppm buckets in AMIX, and multivariate analysis (PLS-DA and O-PLS-DA) was performed in Metaboanalyst 2.0. For other analyses, such as salivary flow, the data was tabulated in the SPSS 20.0 statistical package, analyzed descriptively, and after applying the Wilcoxon test. The interval of confidence was set at 95%.

RESULTS

The mean age was 7.5 (± 1.94), and 47.0% (n = 31) were female, 63.6% (n = 42). The median flow rate for stimulated saliva was 0.74 (IC 0.10-2.40) and was statistically higher (p < 0.001; Wilcoxon test) than unstimulated was 0.39 (IC 0.00-1.80). Children older than seven years old also presented a higher difference between unstimulated and stimulated saliva (p = 0.003; Mann-Whitney test). The PLS-DA and O-PLS-DA demonstrated a different profile in stimulated and unstimulated saliva. Acetate, glucose, propionate, and lysine were higher in the unstimulated whole saliva than in stimulated saliva. Isoleucine, N-acetyl sugar, hydroxybutyrate, glutamate, leucine, propionate, butyrate, valine, isoleucine, succinate, saturated fatty acid, and histidine were found in greater amounts in the saliva of patients with stimulated saliva.

CONCLUSION

The stimulated saliva presented a higher flow rate, and older children exhibited a higher flow rate resulting from it's the stimulus. The mechanical stimulus increased the levels of the major metabolites.

Assessing the influence of sleep and sampling time on metabolites in oral fluid: implications for metabolomics studies

INTRODUCTION

The human salivary metabolome is a rich source of information for metabolomics studies. Among other influences, individual differences in sleep-wake history and time of day may affect the metabolome.

OBJECTIVES

We aimed to characterize the influence of a single night of sleep deprivation compared to sufficient sleep on the metabolites present in oral fluid and to assess the implications of sampling time points for the design of metabolomics studies.

METHODS

Oral fluid specimens of 13 healthy young males were obtained in Salivette® devices at regular intervals in both a control condition (repeated 8-hour sleep) and a sleep deprivation condition (total sleep deprivation of 8 h, recovery sleep of 8 h) and their metabolic contents compared in a semi-targeted metabolomics approach.

RESULTS

Analysis of variance results showed factor 'time' (i.e., sampling time point) representing the major influencer (median 9.24%, range 3.02-42.91%), surpassing the intervention of sleep deprivation (median 1.81%, range 0.19-12.46%). In addition, we found about 10% of all metabolic features to have significantly changed in at least one time point after a night of sleep deprivation when compared to 8 h of sleep.

CONCLUSION

The majority of significant alterations in metabolites' abundances were found when sampled in the morning hours, which can lead to subsequent misinterpretations of experimental effects in metabolomics studies. Beyond applying a within-subject design with identical sample collection times, we highly recommend monitoring participants' sleep-wake schedules prior to and during experiments, even if the study focus is not sleep-related (e.g., via actigraphy).

White Roman Goose Feather-Inspired Unidirectionally Inclined Conical Structure Arrays for Switchable Anisotropic Self-Cleaning

White Roman goose (Anser anser domesticus) feathers, comprised of oriented conical barbules, are coated with gland-secreted preening oils to maintain a long-term nonwetting performance for surface swimming. The geese are accustomed to combing their plumages with flat bills in case they are contaminated with oleophilic substances, during which the amphiphilic saliva spread over the barbules greatly impairs their surface hydrophobicities and allows the trapped contaminants to be anisotropically self-cleaned by water flows. Particularly, the superhydrophobic behaviors of the goose feathers are recovered as well. Bioinspired by the switchable anisotropic self-cleaning functionality of white Roman geese, superhydrophobic unidirectionally inclined conical structures are engineered through the integration of a scalable colloidal self-assembly technology and a colloidal lithographic approach. The dependence of directional sliding properties on the shape, inclination angle, and size of conical structures is systematically investigated in this research. Moreover, their switchable anisotropic self-cleaning functionalities are demonstrated by Sudan blue II/water (0.01%) separation performances. The white Roman goose feather-inspired coatings undoubtedly offer a new concept for developing innovative applications that require directional transportation and the collection of liquids.

Evaluation of Biomarkers of Bone Metabolism on Salivary Matrix in the Remodeling of Periodontal Tissue during Orthodontic Treatment

The aim of this study was to evaluate changes in the concentration of N-terminal type I collagen extension pro-peptide (PINP), tartrate-resistant acid phosphatase (TRAcP), and parathyroid hormone-related protein (PTHrP) in saliva during orthodontic treatment in order to evaluate whether changes in bone turnover marker (BTM) concentration can help highlight the effects of orthodontic mechanical loading in the absence of clinical evidence of tooth movement in terms of tooth movement. Saliva samples from 25 apparently healthy young subjects (10 females and 15 males) were collected using Salivette® (Sarstedt) with cotton swabs and the concentrations of PTHrP, TRAcP 5b, and PINP were analyzed at time 0 (T1), 25 days (T2), and at 45 days (T3). Differences in the median value of biomarker levels between baseline T1 and follow-up of the different groups (T2 and T3) were assessed using the non-parametric Mann-Whitney U test. Trough concentrations of P1NP, PTHrP, and TRAcP were 0.80 µg/L, 0.21 ng/mL, and 0.90 U/L above the method LOD. The non-parametric Mann-Whitney U test confirmed a statistically significant difference in T1 versus concentrations of T2 and T3. All subjects evaluated had a statistically significant difference between T1 vs. T3. when compared with the specific critical difference (RCV) for the analyte The results obtained demonstrate that the evaluation of BTM changes in saliva can help the evaluation of orthodontic procedures and the monitoring of biomechanical therapy.

Navigating Challenges and Opportunities in Multi-Omics Integration for Personalized Healthcare

The field of multi-omics has witnessed unprecedented growth, converging multiple scientific disciplines and technological advances. This surge is evidenced by a more than doubling in multi-omics scientific publications within just two years (2022-2023) since its first referenced mention in 2002, as indexed by the National Library of Medicine. This emerging field has demonstrated its capability to provide comprehensive insights into complex biological systems, representing a transformative force in health diagnostics and therapeutic strategies. However, several challenges are evident when merging varied omics data sets and methodologies, interpreting vast data dimensions, streamlining longitudinal sampling and analysis, and addressing the ethical implications of managing sensitive health information. This review evaluates these challenges while spotlighting pivotal milestones: the development of targeted sampling methods, the use of artificial intelligence in formulating health indices, the integration of sophisticated n-of-1 statistical models such as digital twins, and the incorporation of blockchain technology for heightened data security. For multi-omics to truly revolutionize healthcare, it demands rigorous validation, tangible real-world applications, and smooth integration into existing healthcare infrastructures. It is imperative to address ethical dilemmas, paving the way for the realization of a future steered by omics-informed personalized medicine.

Exploring Periodontal Conditions, Salivary Markers, and Systemic Inflammation in Patients with Cardiovascular Diseases

(1) Background: This cross-sectional investigation appreciated the role of serum C-reactive protein (CRP), several hematologic-cell markers, and salivary inflammation-related molecules [calprotectin (S100A8/A9), interleukin-1β (IL-1β), kallikrein] to predict periodontitis in patients with atherosclerotic cardiovascular disease (ACVD), arrhythmia, or both. Also, we appreciated the relationship between the inflammatory burden and periodontal destruction with the type of cardiac pathology. (2) Methods: Demographic, behavioral characteristics, periodontal indicators, blood parameters, and saliva samples were collected. (3) Results: All 148 patients exhibited stage II or III/IV periodontitis. Stage III/IV cases exhibited significantly increased S100A8/A9 levels (p = 0.004). A positive correlation between S100A8/A9 and IL-1β [0.35 (<0.001)], kallikrein [0.55 (<0.001)], and CRP [0.28 (<0.001)] was observed. Patients with complex cardiac involvement had a significantly higher number of sites with attachment loss ≥ 5 mm [19 (3-30)] compared to individuals with only arrhythmia [9 (3.25-18)] or ACVD [5 (1-12)] [0.048♦ {0.162/0.496/0.14}]. (4) Conclusions: Severe, extensive attachment loss may be indicative of patients with complex cardiac conditions, which underscores the essential role of periodontal status in relation to systemic diseases. The correlations between the rising trends of the inflammatory parameters suggest a potential interconnection between oral and systemic inflammation.

Coupling Miniaturized Stir Bar Sorptive Dispersive Microextraction to Needle-Based Electrospray Ionization Emitters for Mass Spectrometry: Determination of Tetrahydrocannabinol in Human Saliva as a Proof of Concept

Direct coupling of sample preparation with mass spectrometry (MS) can speed up analysis, enabling faster decision-making. In such combinations, where the analysis time is mainly defined by the extraction procedure, magnetic dispersive solid-phase extraction emerges as a relevant technique because of its rapid workflow. The dispersion and retrieval of the magnetic sorbent are typically uncoupled stages, thus reducing the potential simplicity. Stir bar sorptive dispersive microextraction (SBSDME) is a novel technique that integrates both stages into a single device. Its miniaturization (mSBSDME) makes it more portable and compatible with low-availability samples. This article reports the direct combination of mSBSDME and MS using a needle-based electrospray ionization (NESI) emitter as the interface. This combination is applied to determine tetrahydrocannabinol in saliva samples, a relevant societal problem if the global consumption rates of cannabis are considered. The coupling requires only the transference of the magnet (containing the sorbent and the isolated analyte) from the mSBSDME to the hub of a hypodermic needle, where the online elution occurs. The application of 5 kV on the needle forms an electrospray on its tip, transferring the ionized analyte to the MS inlet. The excellent performance of mSBSDME-NESI-MS/MS relies on the sensitivity (limits of detection as low as 2.25 ng mL-1), the precision (relative standard deviation lower than 15%), and the accuracy (relative recoveries ranged from 87 to 127%) obtained. According to the results, the mSBSDME-NESI-MS/MS technique promises faster and more efficient chemical analysis in MS-based applications.

A nitrogen-doped hollow carbon nanospheres-based aptasensor for non-invasive salivary detection of progesterone

Developing an easy-to-use and non-invasive sensor for monitoring progesterone (P4) as a multi-functional hormone is highly demanded for point-of-care testing. In this study, an ultrasensitive electrochemical aptasensor is fabricated for monitoring P4 in human biofluids. The sensing interface was designed based on the porous nitrogen-doped hollow carbon spheres (N-HCSs). The N-HCSs covalently immobilized high-dense aptamer (Apt) sequences as the bioreceptor of P4. The electron transfer of the redox probe was hindered by incubating P4 on the aptasensor surface and forming the P4-Apt complexes. Meanwhile, the signaling was decreased under two wide linear dynamic ranges (LDRs) from 10 fM to 5.6 μM with a limit of detection (LOD) value of 3.33 fM. The aptasensor presented satisfactory selectivity in the presence of different off-target species with successful feasibility for P4 detection in some human urine and saliva samples. The aptasensor with high sensitivity, as an advantage for on-site and sensitive measurement of P4, can be considered a non-invasive tool for routine analysis of real-world clinical samples method.

Emerging Role of Extracellular Vesicles in Intercellular Communication in the Brain: Implications for Neurodegenerative Diseases and Therapeutics

Extracellular vesicles (EVs) are minute lipid-bilayer sacs discharged by cells, encompassing a diverse array of proteins, nucleic acids, and lipids. The identification of EVs as pivotal agents in intercellular communication has sparked compelling research pathways in the realms of cell biology and neurodegenerative diseases. Utilizing EVs for medicinal reasons has garnered interest due to the adaptability of EV-mediated communication. EVs can be classified based on their physical characteristics, biochemical composition, or cell of origin following purification. This review delves into the primary sub-types of EVs, providing an overview of the biogenesis of each type. Additionally, it explores the diverse environmental conditions triggering EV release and the originating cells, including stem cells and those from the Central Nervous System. Within the brain, EVs play a pivotal role as essential mediators of intercellular communication, significantly impacting synaptic plasticity, brain development, and the etiology of neurological diseases. Their potential diagnostic and therapeutic applications in various brain-related conditions are underscored, given their ability to carry specific cargo. Specially engineered EVs hold promise for treating diverse diseases, including neurodegenerative disorders. This study primarily emphasizes the diagnostic and potential therapeutic uses of EVs in neurological disorders such as Alzheimer's Disease, Huntington's Disease, Parkinson's Disease, Amyotrophic Lateral Sclerosis, and Prions disease. It also summarizes innovative techniques for detecting EVs in the brain, suggesting that EVs could serve as non-invasive biomarkers for early detection, disease monitoring, and prognosis in neurological disorders.

Raman hyperspectroscopy of saliva and machine learning for Sjögren's disease diagnostics

Sjögren's disease is an autoimmune disorder affecting exocrine glands, causing dry eyes and mouth and other morbidities. Polypharmacy or a history of radiation to the head and neck can also lead to dry mouth. Sjogren's disease is often underdiagnosed due to its non-specific symptoms, limited awareness among healthcare professionals, and the complexity of diagnostic criteria, limiting the ability to provide therapy early. Current diagnostic methods suffer from limitations including the variation in individuals, the absence of a single diagnostic marker, and the low sensitivity and specificity, high cost, complexity, and invasiveness of current procedures. Here we utilized Raman hyperspectroscopy combined with machine learning to develop a novel screening test for Sjögren's disease. The method effectively distinguished Sjögren's disease patients from healthy controls and radiation patients. This technique shows potential for development of a single non-invasive, efficient, rapid, and inexpensive medical screening test for Sjögren's disease using a Raman hyper-spectral signature.

Identification of Inflammatory Mediators in Saliva Samples From Hospitalized Newborns: Potential Biomarkers?

Saliva measurements serve as a noninvasive tool for clinically monitoring newborns (NB) and children, a vulnerable population with promising potential for both research and clinical practice. Saliva acts as a repository for various inflammatory biomarkers involved in diverse biological functions. Particularly for children, it offers numerous advantages when compared to plasma and urine sampling. Nevertheless, there is a significant knowledge gap regarding detectable levels of cytokines in the saliva of newborns and children, as well as studies aiming to assess the relationship of this content with physiological and pathological processes.

OBJECTIVES

To characterize the levels of 11 inflammatory mediators (IFNg, IL1b, IL2, IL4, IL6, IL8, IL10, IL12, IL17, TNF, and VEGF) in saliva samples from NB on the first and second day of hospitalization in the Neonatal Intensive Care Unit (NICU).

METHOD

Exploratory study, descriptive, nested within a primary clinical, observational, and prospective study, conducted in the NICU of a public hospital in São Paulo, Brazil. Demographic data and vital signs were recorded in the clinical records of 90 NB, and five saliva samples from 5 NB were collected between the first and second day of life (D1-D2) at approximately 8-hr intervals (8-9 am, 4-5 pm, and 11-12 pm). Saliva samples were used for the measurement of 11 cytokines (IFNg, IL1b, IL2, IL4, IL6, IL8, IL10, IL12, IL17, TNF, and VEGF).

RESULTS

Five NBs participated in this exploratory study, and the vital signs showed variability from the first (D1) to the second day (D2) of hospitalization, variability similar to that of the total population of the primary study. The presence and levels of the 11 cytokines were detected in the saliva samples, as well as a statistical correlation between 10 cytokines (IFNg, IL1b, IL2, IL4, IL6, IL10, IL12, IL17, TNF, and VEGF) and vital signs.

CONCLUSIONS

The novelty of measuring inflammatory mediators in saliva samples from hospitalized NBs in the NICU is highlighted, providing support and new perspectives for the development of clinical and experimental research and an opportunity for developing and implementing new salivary biomarkers in different population segments.

Shaping the future of oral cancer diagnosis: advances in salivary proteomics

INTRODUCTION

Saliva has gained increasing attention in the quest for disease biomarkers. Because it is a biological fluid that can be collected is an easy, painless, and safe way, it has been increasingly studied for the identification of oral cancer biomarkers. This is particularly important because oral cancer is often diagnosed at late stages with a poor prognosis.

AREAS COVERED

The review addresses the evolution of the experimental approaches used in salivary proteomics studies of oral cancer over the years and outlines advantages and pitfalls related to each one. In addition, examines the current landscape of oral cancer biomarker discovery and translation focusing on salivary proteomic studies. This discussion is based on an extensive literature search (PubMed, Scopus and Google Scholar).

EXPERT OPINION

The introduction of mass spectrometry has revolutionized the study of salivary proteomics. In the future, the focus will be on refining existing methods and introducing powerful experimental techniques such as mass spectrometry with selected reaction monitoring, which, despite their effectiveness, are still underutilized due to their high cost. In addition, conducting studies with larger cohorts and establishing standardized protocols for salivary proteomics are key challenges that need to be addressed in the coming years.

A simplified protocol for deep quantitative proteomic analysis of gingival crevicular fluid for skeletal maturity indicators

Assessment of craniofacial skeletal maturity is of great importance in orthodontic diagnosis and treatment planning. Traditional radiographic methods suffer from clinician subjectivity and low reproducibility. Recent biochemical methods, such as the use of gingival crevicular fluid (GCF) protein biomarkers involved in bone metabolism, have provided new opportunities to assess skeletal maturity. However, mass spectrometry (MS)-based GCF proteomic analysis still faces significant challenges, including the interference of high abundance proteins, laborious sample prefractionation and relatively limited coverage of GCF proteome. To improve GCF sample processing and further discover novel biomarkers, we herein developed a single-pot, solid-phase-enhanced sample-preparation (SP3)-based high-field asymmetric waveform ion mobility spectrometry (FAIMS)-MS protocol for deep quantitative analysis of the GCF proteome for skeletal maturity indicators. SP3 combined with FAIMS could minimize sample loss and eliminate tedious and time-consuming offline fractionation, thereby simplifying GCF sample preparation and improving analytical coverage and reproducibility of the GCF proteome. A total of 5407 proteins were identified in GCF samples from prepubertal and circumpubertal groups, representing the largest dataset of human GCF proteome to date. Compared to the prepubertal group, 61 proteins were differentially expressed (31 up-regulated, 30 down-regulated) in the circumpubertal group. The six-protein marker panel, including ATP5D, CLTA, CLTB, DNM2, HSPA8 and NCK1, showed great potential to predict the circumpubertal stage (ROC-AUC 0.937), which provided new insights into skeletal maturity assessment.

Changes in salivary oxytocin in response to biologically-relevant events in farm animals: method optimization and usefulness as a biomarker

Although best known for its established role in mediating parturition and lactation, the highly-conserved neuropeptide hormone oxytocin also mediates a range of social and stress-buffering processes across mammalian species. Measurements of peripheral oxytocin in plasma have long been considered the gold standard, but there is increasing interest in developing methods to detect oxytocin non-invasively in saliva. Here we present an analytical and biological validation of a novel method to measure salivary oxytocin (sOXT) in an under-studied research group: farm animals. Given their similarities with humans in physiology and brain, methods that can identify valued social contexts and social relationships for farm animals and investigate their function have implications for clinical research as well as for animal welfare science. However, current methods to measure sOXT vary greatly in terms of sample collection, pre-measurement processing and measurement and more rigorous standardization and validation of methods is critical to determine the utility of sOXT as a biomarker of salient social events and related emotions. We optimized a method for extracting sOXT in pigs and horses and measured sOXT in extracted samples using a commercially available enzyme-immunoassay. Extracted samples were within acceptable ranges for precision (CVs < 15.2%), parallelism and recovery (94%-99%) in both species. Salivary oxytocin increased in samples collected during birth in pigs (Friedmans, p = 0.02) and horses (Wilcoxon, p = 0.02). Salivary oxytocin tended to decrease in sows after a 90-min separation from their piglets (Wilcoxon, p = 0.08). We conclude that sOXT can be reliably linked to physiological events that are mediated by the oxytocinergic system in farm animals, but that more research is needed to determine whether sOXT is a reliable trait marker for more general oxytocin system activation in response to salient social events. Future research should characterize how individual attributes and salivary parameters influence sOXT measurement and should emphasize reporting of analytical and biological validations to increase acceptance of non-invasive methods.