Search Results (8)

Double-layered textile sweat-absorbing underarm pads with a natural antimicrobial treatment can be used to solve the problem of the wetness sensation in the case of increased physical activity or hyperhidrosis. In addition, changeable antimicrobial active underarm pads help to decrease the number of clothing washings, i.e., reducing water consumption and pollution. Another aspect of sustainability is that the underarm pads can be produced from clothing production waste. The moisture absorption capability of six hydrophilic cellulose-based knitted fabrics and two hydrophobic synthetic woven fabrics was investigated. It was found that the best result for next-to-skin moisture absorption and next-to-clothing protection against moisture penetration was achieved by using a double-layered underarm pad composed of a cotton-based fleece knitted structure in the next-to-skin layer and a very thin and tight 100% PA woven fabric in the outer layer. Four samples of impregnated liquid with herbal extracts and essential oils were prepared, and antimicrobial activity was evaluated using the discus method. Textile impregnated with tea tree essential oil, nutmeg, and birch extracts had the highest antimicrobial activity against Gram-positive bacteria—Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus. Full article

The expanding interest in digital biomarker analysis focused on non-invasive human bodily fluids, such as sweat, highlights the pressing need for easily manufactured and highly efficient soft lab-on-skin solutions. Here, we report, for the first time, the integration of microfluidic paper-based devices (μPAD) and non-enhanced Raman-scattering-enabled optical biochemical sensing (Raman biosensing). Their integration merges the enormous benefits of μPAD, with high potential for commercialization and use in resource-limited settings, with biorecognition-element-free (but highly selective) optical Raman biosensing. The introduced thin (0.36 mm), ultra-lightweight (0.19 g), and compact footprint (3 cm²) opto-paperfluidic sweat patch is flexible, stretchable, and conforms, irritation-free, to hairless or minimally haired body regions to enable swift sweat collection. As a great advantage, this new bio-chemical sensory system excels through its absence of onboard biorecognition elements (bioreceptor-free) and omission of plasmonic nanomaterials. The proposed easy fabrication process is adaptable to mass production by following a fully sustainable and cost-effective process utilizing only basic tools by avoiding typically employed printing or laser patterning. Furthermore, efficient collection and transportation of precise sweat volumes, driven exclusively by the wicking properties of porous materials, shows high efficiency in liquid transportation and reduces biosensing latency by a factor of 5 compared to state-of-the-art epidermal microfluidics. The proposed unit enables electronic chip-free and imaging-less visual sweat loss quantification as well as optical biochemical analysis when coupled with Raman spectroscopy. We investigated the multimodal quantification of sweat urea and lactate levels ex vivo (with syntactic sweat including +30 sweat analytes on porcine skin) and achieved a linear dynamic range from 0 to 100 mmol/L during fully dynamic continuous flow characterization. Full article

Leather is often used to make comfortable shoes due to its soft and breathable nature. However, its innate ability to retain moisture, oxygen and nutrients renders it a suitable medium for the adsorption, growth, and survival of potentially pathogenic microorganisms. Consequently, the intimate contact between the foot skin and the leather lining surface in shoes, which are subject to prolonged periods of sweating, may result in the transmission of pathogenic microorganisms and cause discomfort for the wearer. To address such issues, we modified pig leather with silver nanoparticles (AgPBL) that were bio-synthesized from Piper betle L. leaf extract as an antimicrobial agent via the padding method. The evidence of AgPBL embedded into the leather matrix, leather surface morphology and element profile of AgPBL-modified leather samples (pLeAg) was investigated using colorimetry, SEM, EDX, AAS and FTIR analyses. The colorimetric data confirmed that the pLeAg samples changed to a more brown color with higher wet pickup and AgPBL concentration, owing to the higher quantity of AgPBL uptake onto the leather surfaces. The antibacterial and antifungal activities of the pLeAg samples were both qualitatively and quantitatively evaluated using AATCC TM90, AATCC TM30 and ISO 16187:2013 test methods, approving a good synergistic antimicrobial efficiency of the modified leather against Escherichia coli and Staphylococcus aureus bacteria, a yeast Candida albicans and a mold Aspergillus niger. Additionally, the antimicrobial treatments of pig leather did not negatively impact its physico-mechanical properties, including tear strength, abrasion resistance, flex resistance, water vapour permeability and absorption, water absorption and desorption. These findings affirmed that the AgPBL-modified leather met all the requirements of upper lining according to the standard ISO 20882:2007 for making hygienic shoes. Full article

Hyperhidrosis is a condition characterized by excessive sweating that affects at least 5% of the world’s population. It is normally associated with unpleasant body odour which requires continuous maintenance throughout life. Antiperspirants and deodorants are the first-line treatments for hyperhidrosis. However, association of this class of product with the risk of other diseases has increased the search for an effective antiperspirant from natural sources. This study aimed to investigate the antibacterial and antiperspirant activities of Curcuma xanthorrhiza Roxb. Using an in vitro microbial assay against specific bacteria responsible for body odour and rat foot pad analysis. Quality control of the fractionated extract was conducted using reversed-phase HPLC based on two active markers: xanthorrhiza and curcumin. Toxicity tests were conducted based on the OECD guidelines (50–2000 mg/kg). Inhibition zone, MIC, and MBC values of the hexane fraction of C. xanthorrhiza showed equivalent antibacterial activity to positive control (p > 0.05). No swelling, redness, or rashes were observed at the injection area throughout the study. Treatment with 40, 80, and 160 mg/kg of the extract significantly decreased the sweat excretion up to 79.34% (p < 0.05) after 15 min compared to negative control. Histopathology analysis showed the reduced size of the secretory units in plantar sweat glands post treatment compared to negative control. In conclusion, the hexane fraction of C. xanthorrhiza is able to reduce sweat excretion in a rat model and inhibit the growth of bacteria causing body odour. Full article

Sweat is a natural body excretion produced by skin glands, and the body cools itself by releasing salty sweat. Wetness in the underarms and feet for long durations causes itchiness and an unpleasant smell. Skin-friendly reusable sweat pads could be used to absorb sweat. Transportation of moisture and functionality is the current challenge that many researchers are working on. This study aims to develop a functional and breathable sweat pad with antimicrobial and quick drying performance. Three layered functional sweat pads (FSP) are prepared in which the inner layer is made of an optimized needle-punched coolmax/polypropylene nonwoven blend. This layer is then dipped in antimicrobial ZnO solution (2, 4, and 6 wt.%), and super absorbent polymer (SAP) is embedded, and this is called a functional nonwoven (FNW1) sheet. Electrospun nanofiber-based nanomembranes of polyamide-6 are optimized for bead-free fibers. They are used as a middle layer to enhance the pad’s functionality, and the third layer is again made of needle-punched optimized coolmax/polypropylene nonwoven sheets. A simple nonwoven-based sweat pad (SSP) is also prepared for comparison purposes. Nonwoven sheets are optimized based on better comfort properties, including air/water vapor permeability and moisture management (MMT). Nonwoven webs having a higher proportion of coolmax show better air permeability and moisture transfer from the inner to the outer layer. Antimicrobial activity of the functional nonwoven layer showed 8 mm of bacterial growth, but SSP and FSP showed only 6 mm of growth against Staphylococcus aureus. FSP showed superior comfort and antibacterial properties. This study could be a footstone toward highly functional sweat pads with remarkable comfort properties. Full article

Wearable sensors for sweat biomarkers can provide facile analyte capability and monitoring for several diseases. In this work, a green wearable sensor for sweat absorption and chloride sensing is presented. In order to produce a sustainable device, polylactic acid (PLA) was used for both the substrate and the sweat absorption pad fabrication. The sensor material for chloride detection consisted of silver-based reference, working, and counter electrodes obtained from upcycled compact discs. The PLA substrates were prepared by thermal bonding of PLA sheets obtained via a flat die extruder, prototyped in single functional layers via CO₂ laser cutting, and bonded via hot-press. The effect of cold plasma treatment on the transparency and bonding strength of PLA sheets was investigated. The PLA membrane, to act as a sweat absorption pad, was directly deposited onto the membrane holder layer by means of an electrolyte-assisted electrospinning technique. The membrane adhesion capacity was investigated by indentation tests in both dry and wet modes. The integrated device made of PLA and silver-based electrodes was used to quantify chloride ions. The calibration tests revealed that the proposed sensor platform could quantify chloride ions in a sensitive and reproducible way. The chloride ions were also quantified in a real sweat sample collected from a healthy volunteer. Therefore, we demonstrated the feasibility of a green and integrated sweat sensor that can be applied directly on human skin to quantify chloride ions. Full article

The current study examines neural responses to satiety- and fasting-related volatiles and their effect on the processing of body shapes. Axillary sweat was sampled with cotton pads from 10 individuals after 12 h of fasting, and after having consumed a standard breakfast. Pure cotton pads served as the control. The chemosensory stimuli were presented to 20 participants (via a constant-flow olfactometer) exclusively, and additionally as context to images of overweight and underweight avatars. EEG was recorded (61 electrodes), and chemosensory (CSERPs; P1, N1, P2, P3) and visual event-related potentials (VERPs; N1, P2, P3a, P3b) were analyzed. The amplitudes of all positive CSERP components differed more strongly from cotton in response to chemosensory satiety cues as compared to fasting cues (P1: p = 0.023, P2: p = 0.083, P3: p = 0.031), paralleled by activity within the middle frontal and temporal gyrus. Overweight compared to underweight body shapes tended to elicit larger VERP P2 amplitudes (p = 0.068), and chemosensory satiety cues amplified the VERP amplitudes in response to any body shape (P2, P3a, P3b; all p_s ≤ 0.017) as compared to the cotton control. The results indicate that chemosensory satiety cues transmit complex social information, overriding the processing of analogous visual input. Full article

This work describes a multisensing wearable platform for monitoring biomarkers in sweat during the practice of exercise. Five electrochemical sensors for pH, potassium, sodium, chloride, and lactate were implemented in a flexible patch approach, together with a paper microfluidic component, to continuously measure sweat composition. The sensors are fabricated with silicon technologies: ion selective field effect transistors (ISFETs) for pH and ionic species; and a gold thin-film microelectrode for lactate. The latter includes a polymeric membrane based on an electropolymerized polypyrroled structure, where all the biocomponents required for carrying out the lactate analyses are entrapped. The flexible patch is fabricated using hybrid integration technologies, including printed pads defined on a polyimide (Kapton^®) substrate and wire bonding encapsulation of silicon chips. To fix and align the sensors to the flexible substrate, different laminated materials, such as polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), and silicone-based adhesive, were used. The first results show good performance of the sensors—ISFETS sensitivity between 54–59 mV dec⁻¹ for ion ranges in sweat from 2 to 100 mM and lactate sensor sensitivity of −135 × 102 µA M⁻¹ cm⁻² for the range of 2–50 mM. The microfluidic platform has been tested in terms of adequate sensor wettability and rapid response during the time span of exercise activity (2 h) showing excellent results. Full article