Biguanide Hydrochloride Research Articles

Thermosensitive and injectable chitosan-based hydrogel embedding umbilical cord mesenchymal stem cells for β-cell repairing in type 2 diabetes mellitus

A thermosensitive and injectable hydrogel composed of chitosan (CS), chitosan biguanide hydrochloride (CSG) and collagen (CO) could embed umbilical cord mesenchymal stem cells (UC-MSCs), then was applied for the type 2 diabetes mellitus (T2DM) treatment in vivo. UC-MSCs could adhere well on CS/CSG/CO hydrogel surface and cell division could be clearly observed. Especially, UC-MSCs maintained alive till they grew in CS/CSG/CO hydrogel for 8 days, while the amount of UC-MSCs was limited due to the steric hindrance in hydrogel. To T2DM mice contrastive treatment by intraperitoneal injection for thirteen weeks, UC-MSCs + Hydrogel group could improve the impaired glucose tolerance, maintain glucose homeostasis in vivo, and restore islet morphology for T2DM mice. The immunofluorescence staining and western blot experiments further displayed that both the nuclear antigen Ki67 for cell proliferation and pancreatic duodenal homeobox-1 (Pdx1) expression in UC-MSCs + Hydrogel group were significantly higher than the expressions in untreated T2DM group and treated UC-MSCs + PBS group, which indicated that UC-MSCs + Hydrogel elevated β cell transcriptional activity. Moreover, the positivity rates of iNOS and CD163 in UC-MSCs + Hydrogel group were generally decreased and increased, respectively, compared to those in untreated T2DM group and treated UC-MSCs + PBS group. It displayed that UC-MSCs + Hydrogel could reduce M1 macrophage expression and increase M2 macrophage polarization in T2DM mice.

Regulating Functional Groups to Construct a Mild Passivator Enhancing the Efficiency and Stability of Carbon-Based Perovskite Solar Cells.

The abundant defects on the perovskite surface greatly impact the efficiency improvement and long-term stability of carbon-based perovskite solar cells. Molecules with electron-donating or electron-withdrawing functional groups have been cited for passivating various defects. However, few studies have investigated the potential adverse effects arising from the synergistic interactions among functional groups. Herein, we investigate the correlation between functional group configurations and passivation strength as well as the potential adverse impacts of strong electrostatic structures by methodically designing three distinct interface molecules functionalized with different ending groups, which both belong to biguanide derivatives, including 1-(3,4-dichlorophenyl) biguanide hydrochloride (DBGCl), metformin hydrochloride (MFCl), and biguanide hydrochloride (BGCl). The results indicate that DBGCl establishes comparatively mild active sites, not only passivates defects but also aids in forming a surface with a uniform potential. Conversely, MFCl exerts a more pronounced adverse effect on the perovskite surface, which is attributable to the electronic state perturbations induced by its functional groups. Due to the lack of hydrophobic groups, devices treated with BGCl demonstrate insufficient moisture resistance. Devices passivated with DBGCl demonstrate superior average efficiency, showcasing a 12% enhancement relative to the pristine. Furthermore, DBGCl-treated devices exhibit enhanced stability in three different environments, respectively, achieving the highest PCE retention rates under nitrogen conditions (25 °C), room-temperature air conditions (25 °C, RH = 40 ± 2%), and high-temperature air conditions (65 °C, RH = 40 ± 2%).

Biodegradable gelatin/pectin films containing cellulose nanofibers and biguanide polymers: Characterization and application in sweet cherry packaging

To expand the utilization of gelatin and pectin derived from agricultural by-products, the composite films composed of gelatin, citrus pectin, cellulose nanofibers (CNF), and polyhexamethylene biguanide hydrochloride (PHMB) were prepared through the solvent casting method. Fourier infrared spectroscopy analysis verified the successful integration of CNF and PHMB into the gelatin-pectin matrix. The incorporation of CNF as a reinforcing agent substantially enhanced the barrier capabilities of the composite film. Moreover, the addition of PHMB, functioning as an antimicrobial agent, not only granted the film with antibacterial properties but also improved its physical characteristics and biodegradability. A water contact angle experiment revealed the film presented a certain degree of hydrophobicity. The optimal performances were attained with a composition in which CNF and PHMB constituted 8 % and 3 %, respectively, of the total weight of gelatin and pectin. As a packaging film, the composite film demonstrated its effectiveness by reducing the decay index and weight loss rate of sweet cherries during a 12-day storage period. In the soil degradation test, the composite film exhibited notable structural degradation by the 16th day. Consequently, the composite film will be used as an innovative and biodegradable packaging material to provide a sustainable solution for food packaging industries.

Dual-mode microring resonator for humidity sensing with temperature compensation

On-chip refractive index (RI) sensors, which use resonant shifts of micro-cavities to detect environment change, have the advantages of high sensitivity, real-time detection, and compact footprints. However, the cross-sensitivity of the temperature variation severely interferes with sensing results. In this paper, we present a dual-mode microring resonator (MRR) with a cladding layer of polyhexamethylene biguanide hydrochloride (PHMB) for relative humidity (RH) sensing to overcome the limitation. Specifically, the influences of the RH-induced RI change of the PHMB cladding and temperature variations on the effective RIs of TE0 and TE1 modes can be decoupled based on the transmission spectral measurements. Using this method, we have demonstrated the temperature-compensated RH sensing which achieved a maximum sensitivity of −54.7 pm/%RH and a limit of detection of 0.8 %RH under the room temperature condition. Besides, a computational model based on the sensing response of the device was proposed and verified, which demonstrated that the structure can accurately measure changes in RH and temperature simultaneously. Our methodology has the potential to become a new reference for developing on-chip RI sensors with temperature compensation.

High‐Performance Inverted Perovskite Solar Cells by Dual Interfaces Modification with Identical Organic Salt

AbstractThe improvement of power conversion efficiency (PCE) and stability of perovskite solar cells (PSC) relies on the enhanced quality of perovskite layer and the modification of its adjacent interfaces. For this purpose, a multifunctional organic passivation molecule 1‐(4‐Fluorophenyl) biguanide hydrochloride (F‐BHCl) is introduced to the top and bottom interfaces of the perovskite layer. The PCE of PSC after the modification of double interfaces with F‐BHCl is significantly increased from 22.41% (unmodified) to 25.14%, and the storage, thermal, and operation stability is also improved. The comprehensive theoretical and experimental studies verify that due to its versatile functional groups and adaptation, F‐BHCl can significantly improve the quality of perovskite film, fully passivate several kinds of common defects, smoothen the top surfaces of perovskite film, and construct “molecular bridges” with carrier transporters on both the top and bottom surfaces, leading to significantly reduced non‐recombination and carrier transport losses. As a result, a significant increase is achieved in the open circuit voltage and fill factor as well as the whole performance of the device.

Ionic conductive soluble starch hydrogels for biocompatible and anti-freezing wearable sensors

Hydrogel sensors have been widely researched for their good biocompatibility and mechanical properties similar to those of human skin, enabling the monitoring and transmission of a wide range of signals, thus promoting the development of flexible wearable electronic devices. However, long-term direct contact between hydrogel sensors and human skin can cause bacterial infection phenomena, and endowing hydrogel materials with antimicrobial properties is an important challenge in sensing applications. Here, an antimicrobial hydrogel was researched and explored via a freeze–thaw method introducing soluble starch, polyhexamethylene biguanide hydrochloride, glycerin, lithium chloride, and polyvinyl alcohol. The hydrogel expressed remarkable frost resistance, water retention, fatigue resistance, stability, sensitivity, responsiveness, electrical conductivity. The hydrogel exhibited an inhibitory loop resistant to Escherichia coli and Bacillus subtilis and emerged an inhibitory stability over 7 days. Simultaneously, the hydrogel expressed biocompatibility without tissue contamination, inflammation and other adverse phenomena under the skin of mice for 14 days. Furthermore, the hydrogel could record the signals of deformation during the process of the human motion. Therefore, the simple strategy is promising for medical fields including human motion detection, physiological signal recording and medical health detection.

In Vitro Model to Evaluate the Development of Discolorations on Human Enamel Caused by Treatment with Mouth Rinses and Black Tea Considering Brushing.

The study aimed to develop and test an in vitro model to investigate the staining potential of mouth rinses on human enamel, considering alternating intake of black tea and tooth brushing, thus mimicking the situation in the oral cavity more realistically. Eight mouth rinses with six different active ingredients (benzydamine hydrochloride [BNZ], polyhexamethylene biguanide hydrochloride [PHMB], chlorhexidine digluconate [CHX], hexetidine gluconate [HEX], octenidine dihydrochloride [OCT] and octenidine dihydrochloride + 2-phenoxyethanol [OCTP]) and concentrations were tested. Sets of six halved human molar crowns were initially pretreated by soaking in artificial saliva (30 min). Afterward, the cyclic treatment was started by soaking in artificial saliva (2 min), staining with black tea (1 min), brushing with toothpaste (5 s), and soaking in the mouth rinse (30 s). Samples were rinsed with distilled water after each treatment step. The cyclic treatment was repeated 30 times, mimicking the consumer behavior after 15 days. Photographic images were taken after 0, 10, 20, and 30 cycles. Color measurements were conducted after each staining and brushing step using a VITA-Easyshade spectrophotometer to determine the difference in lightness ∆L and the total color difference ∆E. Analysis of variance and post-hoc Tukey test (α = 0.05) were applied. The new testing model with included brushing sequences allowed to assess the staining behavior on human teeth and provided a clear differentiation between the different investigated products. In detail, up to cycle 10, ΔE values increased for all mouth rinses with each additional cycle number. However, while ΔE values continued to increase for 0.15% BNZ, 0.1% PHMB, and 0.2% CHX between treatment cycle 10 and 30, ΔE values only slightly increased after treatment with 0.08% OCTP, 0.1% OCTP, 0.1% OCT, and 0.1% HEX. After 20 and 30 cycles, significantly less staining was found for 0.08% OCTP, 0.1% OCT, 0.1% HEX as compared to 0.2% CHX, 0.15% BNZ, and 0.1% PHMB (p < 0.05). ΔE-values were significantly lower after treatment with 0.1% OCTP as compared to 0.2% CHX1 and 0.2% CHX2 (p < 0.05). The proposed new methodology was found to be appropriate for assessing the staining progression of mouth rinses over a simulated application period of 15 days. The model allows differentiation of products with different active ingredients and concentrations.

Development of an antimicrobial and antifouling PES membrane with ZnO/poly(hexamethylene biguanide) nanocomposites incorporation

Although polyethersulfone (PES) membranes are extensively utilized in water and wastewater treatment, they typically encounter serious bio/organic fouling problems. In this work, an antimicrobial and antifouling PES membrane was developed through incorporating novel ZnO/PHMB (zinc oxide/ polyhexamethylene biguanide hydrochloride) nanocomposites on the surface of a commercial PES membrane, with PDA (polydopamine) serving as an intermediate connection layer. XPS, along with synchrotron-based XRF and ATR-FTIR results confirmed the successful synthesis of the ZnO/PHMB nanocomposites and ZnO/PHMB membranes. The ZnO/PHMB nanocomposites exhibited an impressive antimicrobial rate of 99.99 % with a minimal amount of PHMB addition (wtZnO:wtPHMB = 1:0.01). The concentration of the ZnO/PHMB nanocomposites had the most significant impact on the antimicrobial performance of the ZnO/PHMB membrane. The 600ZP membrane (i.e., the PES membrane modified with 600 mg/L ZnO/PHMB nanocomposites) emerged as the optimal choice, as evidenced by its commendable antimicrobial performance (92.80 %), water flux (249.02 LMH), RB (Rose Bengal sodium salt) rejection (93.96 %), and cost-benefit considerations. Compared to the pristine PES membrane, the 600ZP membrane showed 5.32 %, 15.76 %, and 7.62 % increased hydrophilicity, water flux, and RB rejection rate, respectively. Additionally, the 600ZP membrane possessed a bactericidal rate of 92.80 % and a flux recovery rate of 89.24 % after three cycles of SA (sodium alginate) filtration, indicating enhanced antimicrobial and antifouling capacities. The 600ZP membrane exhibited a remarkable 91.05 % higher water flux following prolonged (72 h) treatment of secondary effluent, compared to the PES membrane. Attribute to the increased hydrophilicity, outstanding antimicrobial activity, as well as excellent stability and durability, the as-prepared ZnO/PHMB membrane shows great potential for wastewater treatment.

A Series of Biguanide Ligands and Their Cu(II) Complexes: Cholinesterase Inhibitory and Antimicrobial Properties.

In this work, a series of biguanide hydrochloride salts and their Cu(II) complexes were synthesized and screened for their acetyl/butyryl choline esterase inhibitory and antimicrobial properties. The structures of the synthesized compounds were characterised by common spectroscopic and analytical methods. Biguanide compounds showed considerably lower inhibitory activity compared to the reference drugs donepezil and galantamine. On the other hand, complexation of the biguanide compounds with Cu(II) resulted in dramatic increase in the inhibitory activity. The Cu(II) complexes showed AChE inhibitory activity with the IC50 values of 21.29±0.95-82.53±0.20 μM and those values are comparable to that of donepezil (IC50 : 18.54±1.03 μM). The synthesised compounds were also screened for their antimicrobial activity towards gram positive (+) and gram negative (-) bacteria. Compounds (12.50 mg/mL) showed important antibacterial properties with inhibition zones of 8-28 mm diameter against gram-positive and gram-negative microorganisms. Compounds A03 and A08 exhibited more antimicrobial properties towards E. coli than standard antibiotics amikacin and gentamicin.

Ultra-high strength sodium alginate/PVA/PHMB double-network hydrogels for marine antifouling

Although hydrogel have attracted tremendous attention as antifouling material, it is still challenging to develop an antifouling hydrogel that combines superior mechanical properties with excellent antifouling effect. Here, a high-strength polyvinyl alcohol/sodium alginate double-network (DN) antibacterial and antifouling hydrogel was synthesized by introducing polyhexamethylene biguanide hydrochloride (PHMB) potent fungicide. The as-prepared hydrogel demonstrated high tensile strength (17.23 MPa), excellent anti-protein adhesion ability (0.09 %, anti-diatom adhesion rate), and outstanding antibacterial ability (100 % sterilization rate). The antifouling experiments have verified that DN-PHMB hydrogel remains non-attachment even after >6 months in the actual marine environment. These distinctive capabilities of DN-PHMB hydrogels hold promising candidate for marine antifouling materials.

Culture Shock: An Investigation into the Tolerance of Pathogenic Biofilms to Antiseptics in Environments Resembling the Chronic Wound Milieu.

Credible assessment methods must be applied to evaluate antiseptics' in vitro activity reliably. Studies indicate that the medium for biofilm culturing should resemble the conditions present at the site of infection. We cultured S. aureus, S. epidermidis, P. aeruginosa, C. albicans, and E. coli biofilms in IVWM (In Vitro Wound Milieu)-the medium reflecting wound milieu-and were compared to the ones cultured in the laboratory microbiological Mueller-Hinton (MH) medium. We analyzed and compared crucial biofilm characteristics and treated microbes with polyhexamethylene biguanide hydrochloride (PHMB), povidone-iodine (PVP-I), and super-oxidized solution with hypochlorites (SOHs). Biofilm biomass of S. aureus and S. epidermidis was higher in IVWM than in MH medium. Microbes cultured in IVWM exhibited greater metabolic activity and thickness than in MH medium. Biofilm of the majority of microbial species was more resistant to PHMB and PVP-I in the IVWM than in the MH medium. P. aeruginosa displayed a two-fold lower MBEC value of PHMB in the IVWM than in the MH medium. PHMB was more effective in the IVWM than in the MH medium against S. aureus biofilm cultured on a biocellulose carrier (instead of polystyrene). The applied improvement of the standard in vitro methodology allows us to predict the effects of treatment of non-healing wounds with specific antiseptics.

The Preparation of Nanosized Pd/ZSM-23 Bifunctional Catalysts for n-Hexadecane Hydroisomerization by Employing PHMB as the Growth Modifier

The development of highly effective metal–zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality. In this study, polyhexamethylene biguanide hydrochloride (PHMB) is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites (Z23-xPH). Due to orientation adsorption and steric hindrance effects of PHMB, each sample of Z23-xPH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite. Furthermore, the Brønsted acid density of the Z23-xPH samples is also significantly reduced due to a reduction in the distribution of framework Al at T2–T5 sites. The corresponding Pd/23-C and Pd/Z23-xPH bifunctional catalysts with 0.5 wt% Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports. According to the catalytic test results, the suitable addition of PHMB can effectively promote the iso-hexadecane yield. The Pd/Z23-2PH catalyst with an nPHMB/nSi molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1% at an n-hexadecane conversion of 88.3%. Therefore, the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.

Antimicrobial and anti-freezing conductive hydrogels driven by quaternary ammonium chitosan salt for flexible strain sensors

Conductive hydrogels have great development prospects in the field of flexible strain sensors due to the unique characteristics of sufficient flexibility, comfort and functional diversification. However, long-term direct contact between hydrogel sensors and human skin can cause the phenomenon of bacterial infection, which accelerates the replaceable frequency of hydrogel wearable sensors, hindering the application of hydrogel wearable sensors. Here, the hydrogel with distinguished antibacterial, biocompatibility, frost resistance, water retention and toughness were designed and manufactured by a freeze–thaw method introducing polyvinyl alcohol, quaternary ammonium chitosan salt, polyhexamethylene biguanide hydrochloride, glycerin and lithium chloride. The hydrogel maintains remarkable tensile properties and fatigue resistance in the range from 25 °C to −20 °C, expanding the application of hydrogels as sensors. Meanwhile, the hydrogel was resistant to E. coli and Bacillus subtilis and could be preserved in mice for 14 days. As a result, the hydrogel sensors could be used to detect human movement in real time, such as finger bending, frowning, speaking and other movements. Therefore, the design of the hydrogel provides a simple research idea for implantable sensing devices.

Polarity-dominated chitosan biguanide hydrochloride-based nanofibrous membrane with antibacterial activity for long-lasting air filtration

Facemasks play a significant role as personal protective equipment during the COVID-19 pandemic, but their longevity is limited by the easy dissipation of electrostatic charge and the accumulation of bacteria. In this study, nanofibrous membranes composed of polyacrylonitrile and chitosan biguanide hydrochloride (PAN@CGH) with remarkable antibacterial characteristics were prepared through the coaxial electrospinning process. Particulate matter could be efficiently captured by the fibrous membrane, up to 98 % or more, via polarity-dominated forces derived from cyano and amino groups. As compared commercial N95 masks, the PAN@CGH was more resistant to a wider variety of disinfection protocols. Additionally, the nanofibrous membrane could kill >99.99 % of both Escherichia coli and Staphylococcus aureus. Based on these characteristics, PAN@CGH nanofibrous membrane was applied to facial mask, which possessed an excellent and long-lasting effect on the capture of airborne particles. This work may be one of the most promising strategies on designing high-performance face masks for public health protection.

Clinical protective effects of polyhexamethylene biguanide hydrochloride (PHMB) against Vibrio parahaemolyticus causing translucent post-larvae disease (VpTPD) in Penaeus vannamei

A new emerging disease called “translucent post-larvae disease” (TPD) in Penaeus vannamei, caused by a novel type of highly lethal Vibro parahaemolyticus (VpTPD), has become an urgent threat to the shrimp farming industry in China. In order to develop an effective disinfectant for the prevention and control of the VpTPD, the clinical protective effects of polyhexamethylene biguanide hydrochloride (PHMB) against VpTPD in Penaeus vannamei were investigated by carrying out an acute toxicity test of PHMB on post-larvae of P. vannamei and its effect of treatment test on VpTPD infection. The results showed that the median lethal concentration of disinfectant (LC50) values of PHMB to post-larvae of P. vannamei after treatment for 24 h, 48 h, 72 h, 96 h were 16.13 mg/L (14.18–18.57), 10.77 mg/L (9.93–11.72), 9.68 mg/L (8.53–11.64), 9.14 mg/L (7.70–10.99), respectively. In addition, a clinical trial showed that 1 mg/L PHMB showed a strong protective effect on the post-larvae of shrimp challenged with 101-104 CFU/ml of VpTPD. The relative percentage survival (RPS) of 1 mg/L PHMB on post-larvae of P. vannamei challenged with VpTPD at 101, 102, 103 and 104 CFU/ml were 63.65 %±6.81, 62.96 %±5.56, 60.00 %±3.75 and 66.67 %±3.75 at 96 hours post infection. The results highlight the clinical protective effects of the PHMB and therefor PHMB can be used as a preventive measure to control early TPD infection in shrimp culture. This study also provides valuable information for the prevention of other bacterial diseases in shrimp culture.

Surface-Modified Carboxylated Cellulose Nanofiber Hydrogels for Prolonged Release of Polyhexamethylene Biguanide Hydrochloride (PHMB) for Antimicrobial Applications.

The surface modification of cellulose nanofibers (CNFs) using a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/sodium bromide (NaBr)/sodium hypochlorite (NaClO) system was successful in improving their hydrophilicity. Following that, we fabricated hydrogels containing carboxylated cellulose nanofibers (c-CNFs) and loaded them with polyhexamethylene biguanide (PHMB) using a physical crosslinking method, aiming for efficient antimicrobial uses. The morphological and physicochemical properties of all hydrogel formulations were characterized, and the results revealed that the 7% c-CNFs-2 h loaded with PHMB formulation exhibited desirable characteristics such as regular shape, high porosity, good mechanical properties, suitable gel content, and a good maximum swelling degree. The successful integration of PHMB into the c-CNF matrix was confirmed by FTIR analysis. Furthermore, the 7% c-CNFs-2 h loaded with the PHMB formulation demonstrated PHMB contents exceeding 80% and exhibited a prolonged drug release pattern for up to 3 days. Moreover, this formulation displayed antibacterial activity against S. aureus and P. aeruginosa. In conclusion, the novel approach of c-CNF hydrogels loaded with PHMB through physical crosslinking shows promise as a potential system for prolonged drug release in topical drug delivery while also exhibiting excellent antibacterial activity.

Flexible hydrogel sensor with excellent antibacterial and low temperature frost resistance

Conductive hydrogels are ideal for preparing wearable sensing devices due to their excellent stretchability and flexibility. However, most hydrogels exhibit poor frost resistance, weak water retention, and lack of biocompatibility and antibacterial properties. In this paper, polyvinyl alcohol (PVA) was used as the skeleton, water, and glycerol formed a binary solvent system, and lithium chloride and polyhexamethylene biguanide hydrochloride (PHMB) were added to the hydrogel system as functional materials. The participation of glycerol not only endowed PVA hydrogels with excellent frost resistance but also formed hydrogen bond interaction with PVA, which improved the mechanical properties of hydrogels. Meanwhile, adding PHMB made hydrogel performs excellent antibacterial properties, effectively killing E. coli (Gram-negative bacteria) and B. subtilis (Gram-positive bacteria). Furthermore, based on the introduction of LiCl, the hydrogel displayed high electrical conductivity. The prepared hydrogel sensor could repeatedly detect and distinguish between various human activities, such as walking, frowning, and speaking. Therefore, prepared multifunctional hydrogels possessed excellent application potential in the medical field, health monitoring, and other fields.

Efficacy of two contact lens disinfecting solutions in reducing growth rate of bacteria and eradication of biofilms

Efficacy of two types of contact lens disinfecting (CLD) solutions, most frequently purchased from Jordanian pharmacies by contact lens wearers, was investigated for reducing growth rate of methicillin resistant and methicillin sensitive Staphylococcus aureus, Serratia marcesence, S. liquefacience and Acinetobacter spp., previously isolated from In-use disinfecting solutions in CL cases. Each species was cultured in a clean and dirty conditions (to mimic real situation) of two fresh CLD solutions separately: A and B whose active agents are: Polyhexamethylene biguanide hydrochloride and Polyaminopropyl biguanide respectively. Log reduction of these bacteria have exceeded ISO 14729 acceptable criteria (3 log) and reached up to 5 log reduction. Dirty conditions have marked effect in reducing efficacy of CLD solution (A) to kill bacterial species under test. Biofilms produced by S. marcescens and S. liquefaciens were reduced by more than 50% after 24 hrs. using either CLD solutions, though it was less than that reduced after 4 hrs. Biofilm of methicillin resistant Staphylococcus aureus (MRSA) was the most affected by either CLD solutions after 4 hours. This study concluded that CL wearers should pay great consideration to cleaning and disinfection practices to decrease bacterial growth, reduce chances of biofilm formation.

Ion Exchange Induced Efficient N‐Type Thermoelectrics in Solid‐State

AbstractHigh‐performance n‐type solid‐state ionic thermoelectrics (SS i‐TEs) for low‐grade heat harvesting are highly desired and challenging. Here, the design and synthesis of an efficient n‐type mixed conductor via ion pair modulation is demonstrated, which consists of biguanide hydrochloride (MfmCl) and a poly(3,4‐ethylenedioxythiophene) (PEDOT): poly(styrenesulfonate) (PSS) polymeric complex in a solid film. Theoretical calculations and nano/microstructure characterization reveal that the binding preference of ion pairs offers energetically favorable ion exchange in the matrix, which induces not only tightly bound Mfm PSS species but also favorable anion diffusion channels. Consequently, an enhanced ionic conductivity of 1.40 S m−1 with a record highest negative thermopower of −46.97 mV K−1 is achieved for the n‐type mixed conductor thus far.

Acetylated Distarch Phosphate-Mediated Tough and Conductive Hydrogel for Antibacterial Wearable Sensors.

Conductive, stretchable, and flexible hydrogel wearable sensors have attracted extensive attention in the fields of artificial intelligence and electronic equipment. However, it is an enormous challenge to fabricate conductive hydrogel sensors with biocompatibility, antibacterial properties, and toughness. Here, a highly conductive hydrogel with excellent toughness, good biocompatibility, and strong antibacterial properties was prepared by incorporating acetylated distarch phosphate (ADSP) into poly(vinyl alcohol) (PVA)/polyhexamethylene biguanide hydrochloride (PHMG). The addition of ADSP not only ionized sodium ions to make the hydrogel conductive but also provided abundant hydroxyl groups to form hydrogen bonds with PVA to improve the toughness of the hydrogel. Furthermore, PHMG endowed the hydrogel with antibacterial properties toward E. coli (Escherichia coli, Gram-negative bacteria) and S. aureus (Staphylococcus aureus, Gram-positive bacteria). Meanwhile, the hydrogel was implanted in mice for 14 days, and the surrounding tissue remained in good condition. More importantly, the hydrogel could detect ECG signals and electrical signals under different actions. This study affords a novel approach for exploiting wearable sensors with antibacterial properties and biocompatibility.