Silver-coated Fabrics Research Articles

Plasma jet printing of silver nanoparticles on polyester fabric as a surface-enhanced Raman scattering substrate

Plasma printing techniques are being developed as a novel approach for depositing various functional materials. This study indicates direct one-step printing of silver nanoparticles on various flexible substrates introduce. This technique employs silver nitrate solution as the precursor that are injected, in an aerosol state, into a non-thermal plasma jet. The plasma chamber reduces the injected in-flight droplets, producing silver nanoparticles, which are then deposited on polyester fabrics in a controlled fashion. The structure and morphology of Ag-printed fabrics were characterized by field-enhanced scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy-dispersive X‐ray (EDX). XRD confirmed the face-centered cubic crystalline structure for the printed nanoparticles, whereas FESEM results suggested that the nanoparticles have an almost spherical shape. Various concentrations of Rhodamine B were employed to determine the surface-enhanced Raman scattering (SERS) performance of the silver-coated polyester fabric. Elucidating that even in low concentrations of 10 nM the silver-coated fabrics can detect the Rhodamine B molecules. The highest SERS performance was recorded for Ag-printed fabric using a 6 kV plasma voltage. Also, it was demonstrated that the coated fabric has the flexibility for determining the analyte molecules collected through the swabbing process.

Superhydrophobic and Durable Silver-Coated Fabrics for Efficient Electromagnetic Interference Shielding

Superhydrophobic surfaces present promising potential for improving the mechanical and chemical durability of electromagnetic interference (EMI) shielding materials. However, integrating superhydrophobicity and EMI shielding is still a challenge due to the complex structural design. Herein, superhydrophobic and highly durable fabrics with excellent EMI shielding effectiveness were fabricated. First, the meta-aramid nonwoven fabrics were functionalized by a polydopamine layer. Then, with the assistance of the metal-binding ability of polydopamine, silver nanoparticles were immobilized on the fiber surface by electroless plating. Finally, after the introduction of fluorine-containing agents via a facile dipping method, a superhydrophobic surface was successfully obtained. The as-prepared fabrics showed excellent EMI shielding effectiveness of 111 dB due to superior electrical conductivity (234 S/cm). Moreover, thanks to the low surface energy of fluorine-containing molecules as well as the micro-nanoroughness created by the stacking of silver nanoparticles, the composite fabrics exhibited a large water contact angle of 152° and a low sliding angle of 5°. It was noted that the composite fabrics still maintain superhydrophobicity and high EMI shielding effectiveness (110 dB) even after the acid and alkali corrosion, bending, abrading, and salt fog test, respectively, demonstrating their durability under harsh environments.

Scalable coating process of AgNPs-silicone on cotton fabric for developing hydrophobic and antimicrobial properties

Developing a scalable and cost-effective coating process is critical to manufacturing cotton-based hydrophobic antimicrobial fabric for various commercial applications. This paper describes a scalable, cost-effective coating process that is compatible with the existing industrial finishing processes of fabrics. In this process, the fabric is continuously dipped in water-based silver salt and the reducing agent solution to impart silver particles on the fiber surface to produce different coated samples. The process is tuned to minimize process cost and material cost and maximize the antimicrobial effectiveness and durability of the fabric. This paper also introduces an easy protective coating technique with silicone binder of the antimicrobial fabric that improves the durability and hydrophobicity of the antimicrobial fabric without sacrificing the comfort properties of textile fabrics. In the presence of silicone binder, the samples show significant antibacterial effectiveness against two microorganisms, gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria. Qualitative assessment is carried out to evaluate the antimicrobial properties of the silicone encapsulated silver particles-coated fabrics. Moreover, among the silver-coated fabrics of different cycles, silver nanoparticles (AgNPs) are deposited in the 1 cycle of silver-coated fabric and the average particle size deposited onto the fiber surface is 65.52 ± 2.71 nm. After silicone encapsulation, among all encapsulated samples, 1 cycle of silver-coated silicone encapsulated sample shows the best result in terms of antimicrobial efficacy where silicone encapsulated 1 cycle silver-coated sample shows around the zone of inhibition 0.53 and 0.25 mm and encapsulated 2 cycles silver-coated sample shows the zone of inhibition 0.14 and 0.06 mm for S. aureus and E. coli, respectively. Coated fabrics with and without silicone encapsulation are characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy.

Protecting Wearable UHF RFID Tags With Electro-Textile Antennas: The challenge of machine washability

Ultrahigh frequency radio-frequency identification (UHF RFID) tags have shown enormous potential in wearable applications for sensing human vital signs. However, the integration of UHF RFID tags in clothing to achieve machine washability remains a challenge. In this study, we investigated different ways of protecting wearable UHF RFID tags with electro-textile antennas against repeated washing. We replaced the antennas of commercial UHF RFID tags with the antennas made from a silver-coated fabric. Twenty-three types of methods, including five integrated circuit (IC)-protection methods and seven fixation/cover methods, were compared, with each having ten identical samples. The 230 samples underwent 20 cycles of machine washing and drying, and the changes in received signal strength indicator (RSSI) and the number of failed tags after washing were recorded and analyzed statistically. We found that 1) water penetration does not have a negative impact on tag functionality, therefore, being waterproof is not a requirement for the coating material; 2) heat-bond hem taping is the most efficient IC protection method; 3) heat and high pressure is effective to improve tag endurance; and 4) fusible interlinings and ironing, used in traditional garment production, can be effective.

Innovative Therapeutics in Pediatric Dermatology

Although clinical trials for new drugs are often limited in children because of safety concerns or restrictions, new therapies or novel strategies with old drugs have recently expanded dermatologic armamentarium for pediatric patients. Oral propranolol is currently the first choice in the treatment of alarming infantile hemangiomas. In atopic dermatitis, proactive strategy with topical calcineurin inhibitors can safely prevent disease exacerbation. Tacrolimus, in particular, is also useful for the treatment of vitiligo occurring in sensitive areas such as the eyelids. Among biologic drugs, use of etanercept is safe and efficient in children and adolescents with moderate-to-severe plaque psoriasis. Engineered tissues with special antimicrobial properties (silver-coated fabrics or engineered silk) are now used to treat eczema and fungal diseases in children. In athlete's foot, the use of 5-finger socks can also be helpful.

Efficacy of silver-coated fabric to prevent bacterial colonization and subsequent device-based biofilm formation.

Efficacy of silver-coated poly(ethylene terephthalate) to prevent bacterial attachment and subsequent infection was quantified in vitro, in both batch- and flowing-fluid experiments. Kinetic analysis of batch suspended cell cultures of Staphylococcus epidermidis (SE), at various growth-limiting nutrient concentrations, in the absence of any fabric, indicated a maximum culture growth rate constant micro(max) = 0.78 +/- 0.02 h(-1). Batch experiments for Control fabric samples indicated that SE cultures exhibited about the same suspended cell growth rate (0.72 +/- 0.02 h(-1)) as observed in batch suspended cultures without fabric. Suspended SE cultures in the presence of silver-coated fabric grew at a considerably lower rate, 0.15 +/- 0.01 h(-1), indicating the inhibitory effect of Ag(+2) ion released from the fabric. Growth rates of suspended SE cultures were 5-6 times higher in the fluid phase in contact with the Control fabric compared to cultures exposed to silver-coated fabric. Maximum suspended cell concentrations attained at time = 24 h were 1-2 orders of magnitude higher for Control fabrics vs. silver-coated fabric. In all batch colonization experiments, both live and dead SE bacterial cells accumulate on the surfaces of both silver-coated and Control fabrics. Adherent viable SE cells accumulated to 1-2 orders of magnitude more ( approximately 5 x 10(+8) cells/cm(2)) on Control fabric than SE cells on the silver-coated fabric ( approximately 1.1 x 10(+6) cells/cm(2)), respectively. Between 70-95% SE cells on the Control fabric were viable, while on the silver-coated fabric samples, at 24 h, viable cells were less than 10% of the adherent community (i.e., greater than 90% nonviable cells). In flow cell colonization experiments, SE cells accumulated on Control fabric to a maximum adherent cell concentration of 6 x 10(+7) - 8 x 10(+7) cells/cm(2) by 24 h with the proportion of viable cells remaining relatively constant at 76% throughout an experiment. Both noninvasive microscopic enumeration and destructive assays gave the same results for adherent cell numbers. Using silver-coated fabric, total cells numbers (live + dead) reached a level of approximately 1.1 x 10(+7) - 3.0 x 10(+7) cells/cm(2) after about 6 h and remained constant. However, while the proportion of viable cells initially on the surface was 63-75%, this fraction dropped continuously during each experiment to less than 6% viable cells at 24 h. Regardless of the criteria, the number of viable or nonviable cells attached to silver-coated fabric were significantly lower than on Control fabric.

Inhibitory effects of electrically activated silver material on cutaneous wound bacteria.

Silver has had a widespread application in the care of burn wounds and chronic skin ulcers. The in vitro evaluation of unbound ionic silver is reported in this study. A comparison is made between silver-coated fabric alone and the fabric acting under direct electric current anodization. A variety of commonly found predominant skin pathogens were tested in this comparative study. Our studies confirm previous reports demonstrating an effective penetration of the silver ion and its local antibacterial action. Accurate measurements of the bacteria-free "clear zones" surrounding the electrically activated silver-coated fabric showed these to be significantly larger than those of the silver fabric without electric stimulation. This method affords another option in the use of silver for its antibacterial property, i.e., by iontophoresis. Its potential clinical use awaits further in vivo trials.

Electric silver antisepsis.

Use of silver as a topical antimicrobial agent has been hampered by the absence of a method of providing sustained delivery of the silver ions. One possible solution is the use of silver-coated fabrics as both wound dressings and silver-ion emitting anodes in a simple electric circuit. The antimicrobial dose would then be determined by Faraday's law. In the biological environment, silver-coated materials studied thus far have not behaved as predicted. We have discovered a silver-coated fabric, designated IT, that is almost perfectly Faradaic in vitro up to 0.8 C. The silver ions thus liberated were effective in inhibiting the growth of microorganisms. IT has potential for development as a charge-controlled topical antimicrobial agent.

Electrical augmentation of the antimicrobial activity of silver-nylon fabrics

We measured the silver levels producedinvitro by three silver-coated fabrics, and the resulting antimicrobial effect onPseudomonasaeruginosa,Staphylococcusaureus, andCandidaalbicans. A significant enhancement of the fabrics' antimicrobial effect was achieved by the passage of weak DC currents, which cause increased liberation of silver ions. The antimicrobial effectiveness of each fabric depended on its textile characteristics. Thus, a silver-coated fabric could potentially serve as an antimicrobial dressing by continuously releasing silver ions into a wound either by passive dissociation or through electrical stimulation.