Synergistic antibacterial effect and mechanism between Cu2O nanoparticles and quaternary ammonium salt in moisture-curable acrylic coatings

Combining with various antibacterial mechanisms is the preferred strategy to fabricate coatings with effective antibacterial performance. Herein, Cu2O nanoparticles and dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride, a kind of quaternary ammonium salt (QAS), were simultaneously incorporated into a moisture-curable acrylic resin in order to achieve both contact-killing and release-killing abilities for antibacterial coatings. The surface morphology, surface composition and basic properties of the coatings were thoroughly characterized. The antibacterial performance of the coatings was determined by in-vitro bacteriostatic test. Under the constant total mass fraction of antibacterial agents, both Cu2O and QAS content possessed the highest value on the coating surface at Cu2O/QAS mass ratio of 1:1, and correspondingly, the coatings reached sterilizing rate above 99 % against both E. coli and S. loihica, indicating the existence of synergistic effect between Cu2O and QAS. The synergistic antibacterial mechanism of the coatings involved two aspects. Firstly, the combination of contact-killing and release-killing biocides resulted in high bactericidal and antibiofilm activity against different bacteria. Further, the grafting of QAS molecules on the surface of Cu2O particles brought about the spontaneous migration of nanoparticles to the coating surface. The interaction between Cu2O and QAS also inhibited the phase separation of QAS and prolonged the release of Cu2+ at the same time. The coatings, therefore, exhibited stable antibacterial performance at varied service conditions.

Bioinspired Photoelectronic Synergy Coating with Antifogging and Antibacterial Properties

Optically transparent glass with antifogging and antibacterial properties is in high demand for endoscopes, goggles, and medical display equipment. However, many of the previously reported coatings have limitations in terms of long-term antifogging and efficient antibacterial properties, environmental friendliness, and versatility. In this study, inspired by catfish and sphagnum moss, a novel photoelectronic synergy antifogging and antibacterial coating was prepared by cross-linking polyethylenimine-modified titanium dioxide (PEI-TiO2), polyvinylpyrrolidone (PVP), and poly(acrylic acid) (PAA). The as-prepared coating could remain fog-free under hot steam for more than 40 min. The experimental results indicate that the long-term antifogging properties are due to the water absorption and spreading characteristics. Moreover, the organic-inorganic hybrid of PEI and TiO2 was first applied to enhance the antibacterial performance. The Staphylococcus aureus and the Escherichia coli growth inhibition rates of the as-prepared coating reached 97 and 96% respectively. A photoelectronic synergy antifogging and antibacterial mechanism based on the positive electrical and photocatalytic properties of PEI-TiO2 was proposed. This investigation provides insight into designing multifunctional bioinspired surface materials to realize antifogging and antibacterial that can be applied to medicine and daily lives.

In vitro comparison of antifungal activity of conventional alcohol sprays and antimicrobial photodynamic therapy on acrylic denture resin

BACKGROUND

Traditionally, alcohol sprays are used for disinfection of acrylic-base denture surfaces. A limited number of studies have assessed the role of antimicrobial photodynamic therapy (aPDT) in this regard; however, it remains debatable whether conventional alcohol sprays are superior to aPDT in terms of antifungal activity or vis versa.

OBJECTIVE

The aim of the present in vitro study is to compare the antifungal activity of conventional alcohol sprays and aPDT on acrylic denture resin.

METHODS

Individuals wearing complete dentures at least on one arch were included. Dentures were randomly divided into three groups. Groups 1-3 were disinfected with an alcohol-based antiseptic spray and aPDT, respectively. Assessment of oral yeast growth was done using swab samples. The culture mediums were incubated at 37∘C for 72 hours and viewed through a microscope. The numbers of colony forming units (CFU/ml) were determined. P< 0.05 were considered statistically significant.

RESULTS

At baseline, the mean CFU/ml in Groups 1-3 were comparable. After disinfection, a statistically significant reduction in microbial CFU/ml was observed in Groups 1 (P< 0.05) and 2 (P< 0.05) compared with baseline. In Group 3, there was no difference in CFU/ml throughout the study. After disinfection, there was no difference in microbial CFU/ml in dentures in Groups 1 and 2.

CONCLUSION

Conventional alcohol sprays are as effective as aPDT towards reducing oral yeasts CFU/ml on acrylic denture resin.

Impact of chitosan-incorporated toothpaste on roughness, gloss, and antifungal potential of acrylic resin

This study aimed to test the efficacy of different silica-based toothpastes with or without chitosan, as a method of cleaning the acrylic surfaces of denture prostheses. Acrylic resin specimens were prepared to evaluate surface roughness and gloss (n = 10), and Candida albicans adhesion/inhibition (n = 2). Two toothpastes with different degrees of abrasiveness were used: Colgate (CT) and Elmex (EX), with or without 0.5% chitosan (Ch) microparticles (CTCh or EXCh, respectively). The negative control was brushed with distilled water. Brushing was simulated with a machine. Surface roughness and gloss were analyzed before and after brushing. Candida albicans incidence/inhibition was tested qualitatively to determine the acrylic resin antifungal activity. The roughness and gloss data were analyzed with a generalized linear model, and the Kruskal Wallis and Dunn tests, respectively (α = 5%). Brushing with toothpastes increased roughness and reduced gloss, compared with the negative control (p < 0.05). CT showed a more significantly different change in roughness and gloss, in relation to the other groups (p < 0.05). Addition of chitosan to CT reduced its abrasive potential, and yielded results similar to those of EX and EXCh. Specimens brushed with CT showed a higher potential for Candida albicans adherence, despite its higher antifungal action. Addition of chitosan to the toothpaste made both toothpaste and brushing more effective in inhibiting Candida albicans. CT had the potential to increase roughness, reduce gloss, and increase Candida albicans adherence. In contrast, chitosan added to CT showed greater antifungal potential, and a higher synergistic effect than EX.

The effect of different concentration of emodin nanoparticles, as an antibacterial agent, on the flexural resistance of acrylic resin used in orthodontics: An in vitro study

OBJECTIVE

The aim of this study was to investigate the impact of emodin nanoparticles (n-Emo) on the flexural strength of acrylic resin used in orthodontics.

METHODS

A total of 24 acrylic resin discs were prepared according to ISO:20795-1 and divided into four groups (n=6): 0% n-Emo, 0.5% n-Emo, 1% n-Emo, and 2% n-Emo. The flexural strength of each group was measured using the Universal Testing Machine. One-way analysis of variance (ANOVA) and Tukey tests were used to analyse the data.

RESULTS

The highest flexural strength values were observed in the groups containing 0% and 0.5% concentrations of n-Emo, while the lowest mean flexural strength was recorded in the group containing 2% concentration of n-Emo. There were significant difference in flexural strength values between the groups containing 0% with those containing 1% and 2% concentrations (P=0.045, P=0.011, respectively), as well as between those containing 0.5% and 2% concentrations of n-Emo (P=0.041).

CONCLUSIONS

The results of the study showed that the incorporation of n-Emo had a negative impact on the flexural strength of the acrylic resin utilized in orthodontics. Nonetheless, the mean flexural strength values of all groups fell within the normal range, implying that the addition of n-Emo did not jeopardize the mechanical properties of the acrylic resin. It is therefore conceivable that the use of n-Emo as an antimicrobial agent in acrylic resin could be a promising approach to reducing enamel demineralisation and dental caries, while preserving its mechanical properties. This study was approved by the ethics committee of the Tehran University of Medical Sciences (1401-2-398-54892).

Action of chitosan-based solutions against a model four-species biofilm formed on cobalt-chromium and acrylic resin surfaces

OBJECTIVE

To evaluate the anti-biofilm action of chitosan, nanoparticulate chitosan, and denture cleanser Nitradine™ against biofilms comprising Candida albicans, Candida glabrata, Staphylococcus aureus, and Streptococcus mutans.

BACKGROUND

Biofilm removal from removable partial dentures (RPD) is important for success in prosthetic rehabilitation.

MATERIALS AND METHODS

The anti-biofilm action of the experimental chitosan-based solutions and Nitradine™ was evaluated on acrylic resin and cobalt-chromium alloy through assessing cell viability, cell metabolism, residual aggregated biofilm, and extracellular polymeric substance and biofilm morphology.

RESULTS

Only chitosan reduced the viability of C. albicans on cobalt-chromium alloy surface, by 98% (a 1.7 log10 reduction in cfu). Chitosan-based solutions neither promoted substantial alteration of the metabolic activity of the four-species biofilm nor reduced the amount of the aggregated biofilm. After immersion in chitosan and nanoparticulate chitosan, viable microorganisms and extracellular polymeric substances distributed over the entire specimens' surfaces were observed. Nitradine™ reduced the viability and metabolic activity of biofilm grown on both surfaces, but it did not remove all aggregated biofilm and extracellular polymeric substances. After immersion in Nitradine™, approximately 35% of the specimens' surfaces remained covered by aggregated biofilm, mainly composed of dead cells.

CONCLUSION

Although chitosan and Nitradine™ promoted changes in the viability of microorganisms, neither solution completely removed the four-species biofilm from the Co-Cr and acrylic resin surfaces. Thus, isolated use of hygiene solutions is not indicated for biofilm control on RPDs; this requires complementary mechanical removal.

The effect of zinc oxide (ZnO) nanoparticle concentration on the adhesion of mucin and Streptococcus mutans to heat-cured acrylic resin

Incorporating zinc oxide (ZnO) nanoparticles as antibacterial fillers in heat-cured acrylic resin could decrease mucin and Streptococcus mutans (S. mutans) adhesion, reducing the incidence of dental caries in the baseplates of orthodontic patients. Here, ZnO nanoparticles were modified using 3-(trimethoxysilyl)propyl methacrylate with various concentrations, added to acrylic resin powder, homogenized, mixed with acrylic resin liquid, and processed. The composite systems interfered well with mucin and S. mutans adhesion. The lowest mean of the amount of mucin adhered was on heat-cured acrylic resin with 7.5% ZnO nanoparticles, with a standard deviation of 18.07±0.80 mg/mL. The ZnO nanoparticles with a concentration of 7.5% showed an 87.09±0.88% S. mutans adhesion in control groups with no additives. These composite systems were proven to have better physicochemical characteristics and antibacterial abilities. Combining ZnO nanoparticles with heat-cured acrylic resin has great potential for self-cleaning baseplates of orthodontic patients in the future.

Antimicrobial Activity of Experimental Chitosan Solutions on Acrylic Resin and Cobalt-Chromium Surfaces

PURPOSE

To evaluate the application of chitosan as a cleanser in the control of biofilm formation on cobalt-chromium (Co-Cr) alloy and acrylic resin surfaces.

MATERIALS AND METHODS

In total, 172 Co-Cr discs and 172 acrylic resin discs (14 mm x 3 mm) were contaminated with Streptococcus mutans, Staphylococcus aureus, Candida albicans, or Candida glabrata and incubated for 48 hours. Then, specimens were randomly divided into groups and immersed in the following solutions for 15 minutes: solution without chitosan (WC/control); chitosan solution (CH: 5 mg/mL); chitosan nanoparticle solu.on (CN: 3.8 mg/mL); and effervescent tablet (ET). Biofilm recovery rates (n = 9) were evaluated by counting the colony-forming units (CFU/mL). Biofilm morphology was evaluated using scanning electron microscopy (SEM). Data were compared using the Kruskal-Wallis or ANOVA tests followed by the Tukey post hoc test.

RESULTS

For acrylic resin, ET showed the lowest number of CFU for S aureus and S mutans (P < .001). CH exhibited intermediate values for S mutans, S aureus, and C albicans; CN exhibited intermediate values for S mutans and S aureus. For C glabrata, there was no sta.s.cal difference between the solu.ons (P = .264). For Co-Cr, ET showed the highest level of antimicrobial action against all microorganisms (P < .001), and CH showed an intermediate level of action against S mutans and S aureus. Against C albicans and C glabrata, there was no significant difference among CH, CN, and WC.

CONCLUSIONS

Although ET had a broader spectrum of antimicrobial action, CH showed promise as a denture cleanser. Int J Prosthodont 2023;36:e61-e73.

Anti-multispecies microbial biofilms and anti-inflammatory effects of antimicrobial photo-sonodynamic therapy based on acrylic resin containing nano-resveratrol

BACKGROUND

Polymethylmethacrylate (PMMA)-based removable orthodontic appliances are susceptible to microbial colonization due to the surface porosity, and accumulating the biofilms causes denture stomatitis. the present study evaluated the anti-biofilm and antiinflammatory effects of antimicrobial photo-sonodynamic therapy (aPSDT) against multispecies microbial biofilms (Candida albicans, Staphylococcus aureus, Streptococcus sobrinus, and Actinomyces naeslundii) formed on acrylic resin modified with nanoresveratrol (NR).

MATERIALS AND METHODS

Following the determination of the minimum biofilm inhibitory concentration (MBIC) of NR, in vitro anti-biofilm activity of NR was evaluated. The antibiofilm efficacy against multispecies microbial biofilm including C. albicans, S. aureus, S. sobrinus, and A. naeslundii, were assessed by biofilm inhibition test and the results were measured. To reveal the anti-inflammatory effects of aPSDT on human gingival fibroblast (HGF) cells, the gene expression levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were evaluated via quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

According to the results, the MBIC dose of NR against multispecies microbial biofilm was considered 512 µg/mL. The highest biofilm reduction activity was observed in MBIC treated with aPSDT and 2 × MBIC exposed to light emitting diode (LED) and ultrasound waves (UW). The expression level of TNF-α and IL-6 genes were significantly increased when HGF cells were exposed to multispecies microbial biofilms (P<0.05), while after treatment with aPSDT, the expression levels of genes were significantly downregulated in all groups (P<0.05).

CONCLUSION

Overall, NR-mediated aPSDT reduced the growth of the multispecies microbial biofilm and downregulated the expression of TNF-α and IL-6 genes. Therefore, modified PMMA with NR can be serving as a promising new orthodontic acrylic resin against multispecies microbial biofilms and the effect of this new material is amplified when exposed to LED and UW.

Antimicrobial effect of phytosphingosine in acrylic resin

This study evaluated color stability (CS), anti-adherence effect (AAE), and cell viability of microorganisms on acrylic resin (AR) surface, treated associated or not with sodium percarbonate (SP). AR specimens were prepared, and color analysis was performed before and after the treatments and the CS was calculated. For analysis of AAE, the samples were sterilized by radiation in a microwave oven. Then samples were randomly distributed: phosphate-buffered saline (PBS - control), 0.5% sodium hypochlorite (SH), phytosphingosine (PHS), and phytosphingosine + SP (PHS+Na2CO3). The specimens remained in contact with solutions for 30 minutes and were later contaminated by Candida albicans. Aliquots were seeded in Petri dishes with Sabouraud Dextrose agar and incubated at 37°C for 24 hours. After the incubation, the number of colonies was counted. The cell viability of adhered microorganisms on the AR was evaluated and 20 fields were observed under an epifluorescence microscope, and the percentage of adhered viable cells was calculated. Data were compared (One-way ANOVA, Tukey, p<.05). As for CS, PHS+ Na2CO3 (0.4±0.1) resulted in less change than PBS (0.9±0.2), similar to the other groups (SH [1.0±0.3)]; PHS [0.9±0.2)]). There was no difference for all tested solutions regarding the ability to avoid microorganism adherence (p>0.05), but PHS (11.2±4.1) resulted in a smaller area of adhered viable cells, statistically different from SH (18.2±7.6) and PBS (26.4±10.8). It was concluded that PHS resulted in lower adhered viable cells and when associated with Na2CO3, also shows a lower effect on the CS of AR.

Determining growth inhibition of Candida albicans biofilm on denture materials after application of an organoselenium-containing dental sealant

STATEMENT OF PROBLEM

Denture stomatitis is a chronic inflammatory condition caused by the formation of Candida albicans biofilm on denture bases. It is associated with aggravating intraoral pain, itching, and burning sensations. It can also potentiate cardiovascular diseases and aspiration pneumonia. The problem has thus far eluded efficient, toxic-free, and cost-effective solutions.

PURPOSE

The purpose of this in vitro study was to investigate the effectiveness of organoselenium to inhibit the formation of C. albicans biofilm on the surface of acrylic resin denture base materials when it is either incorporated into the acrylic resin material or coated on the denture surface as a light-polymerized surface sealant.

MATERIAL AND METHODS

Sixty heat-polymerized polymethyl methacrylate disks were fabricated and assigned to 4 groups (n=15): disks coated with a light-polymerized organoselenium-containing enamel surface sealant (DenteShield), disks impregnated with 0.5% organoselenium (0.5% selenium), disks impregnated with 1% organoselenium (1% selenium), and disks without organoselenium (control). C. albicans biofilm was grown on each disk which had been placed in a well of the microtiter plate containing 1-mL brain heart infusion broth inoculated with C. albicans. The plates were incubated aerobically at 37 °C for 48 hours. A confocal laser scanning microscope was used to determine the biofilm thickness, biomass, and live/dead cell ratio. Biofilm morphology was examined with scanning electron microscopy, whereas microbial viability was quantified by the spread plate method. The data were analyzed by using ANOVA and Tukey-Kramer multiple comparisons (α=.05).

RESULTS

The microbial viability, biofilm thickness, biofilm biomass, and live/dead cell ratio were lower (P<.001) on disks in the test groups (DenteShield, 0.5% selenium, 1% selenium) when compared with the control group, with these variables being lowest in the 0.5% selenium and 1% selenium groups. The 0.5% selenium and 1% selenium groups did not differ significantly from each other in any of the variables (P>.05). Scanning electron microscope images showed inhibition of both biofilm growth and yeast to hyphae transition in the DenteShield, 0.5% selenium, and 1% selenium groups, with visible disruption of the biofilm morphology.

CONCLUSIONS

The present study demonstrated that organoselenium, whether incorporated into or coated on the surface of an acrylic resin denture base material, has the potential to inhibit Candida albicans biofilm growth on denture surfaces and as such can be clinically useful for the prevention of denture stomatitis.

Photocatalytic effect-assisted antimicrobial activities of acrylic resin incorporating zinc oxide nanoflakes

To overcome the deficiency of the antimicrobial effect of polymer, zinc oxide nanoparticles have been widely utilized as advanced nanofillers due to their antimicrobial and photocatalytic activity. However, the underlying antimicrobial mechanism has not been fully understood apart from topological and physical characteristics. In this study, we prepared zinc oxide nanoparticles-based acrylic resin to explore its antimicrobial mechanism under controlled mechanophysical conditions by using silane-treated zinc oxide nanoflakes (S-ZnNFs). S-ZnNFs incorporated acrylic resin (poly(methyl methacrylate), PMMA) composites up to 2 wt% were selected based on comparable mechanophysical properties (e.g., roughness, wettability, strength and hardness), possibly affecting antimicrobial properties beyond the zinc oxide nanoparticle effect, to bare PMMA. Antimicrobial adhesion results were still observed in 2 wt% S-ZnNFs incorporated PMMA using Candida albicans (C. albicans), one of the fungal infection species. In order to confirm the antimicrobial effects by photocatalysis, we pre-exposed the UV light on 2 wt% S-ZnNF composites before cell seeding, revealing synergetic antimicrobial effect via additional reactive oxygen species (ROS) generation to C. albicans over zinc oxide nanoparticle-induced one. RNA-seq analysis revealed distinguished cellular responses between zinc oxide nanoparticles and UV-mediated photocatalytic effect, but both linked to generation of intracellular ROS. Thus, the above data suggest that induction of high intracellular ROS of C. albicans was the main antimicrobial mechanism under controlled mechanophysical parameters and synergetic ROS accumulation can be induced by photocatalysis, recapitulating a promising use of a S-ZnNFs or possibly zinc oxide nanoparticles as intracellular-ROS-generating antimicrobial nanofillers in acrylic composite for biomedical applications.

Novel polymethyl methacrylate modified with metal methacrylate monomers: biological, physicomechanical, and optical properties

This study sought to evaluate the physical and antimicrobial properties of a thermopolymerizable acrylic resin (PMMA) modified with metallic methacrylate monomers -zirconia (ZM), tin (TM), and di-n-butyl (DNTMB) methacrylates. Color stability was evaluated before and after immersion of samples in a staining solution by a digital spectrophotometer. The mechanical brushing test was evaluated by the roughness test. The flexural strength test used a mechanical testing machine. Human keratinocytes were used to assess cell viability and the biofilm formation assay was carried out for 5 days, in a microcosms model after one year of specimen storage. For statistical analysis, the method chosen was based on adherence to the normal distribution model and equality of variances (p < 0.05). The addition of DNTMB to PMMA promoted great antimicrobial action, acceptable cytocompatibility, without hampering the physical-mechanical properties of the commercial material. Therefore, the modified PMMA proved to be a promisor alternative to conventional resins.This study sought to evaluate the physical and antimicrobial properties of a thermopolymerizable acrylic resin (PMMA) modified with metallic methacrylate monomers -zirconia (ZM), tin (TM), and di-n-butyldimethacrylate-tin (DNTMB) methacrylates. Color stability was evaluated before and after immersion of samples in a staining solution using a digital spectrophotometer. The mechanical brushing test was evaluated by the roughness test. The flexural strength test used a mechanical testing machine. Human keratinocytes were used to assess cell viability and the biofilm formation assay was carried out for 5 days in a microcosm model after one year of specimen storage. For statistical analysis, the method chosen was based on adherence to the normal distribution model and equality of variances (p < 0.05). The addition of DNTMB to PMMA promoted great antimicrobial action, acceptable cytocompatibility, without hampering the physical-mechanical properties of the commercial material. Therefore, the modified PMMA proved to be a promising alternative to conventional denture base resins for dental use.

A pulp foam with highly improved physical strength, fire-resistance and antibiosis by incorporation of chitosan and CPAM

Bio-inspired borate cross-linked pulp foam (PF) with high porosity and low density can be widely used in many fields. However, PF is flammable, and lack of mechanical strength and antibacterial activity. To solve these issues, an ultra-strong PF was prepared by incorporation of chitosan and cationic polyacrylamide (CPAM). Results showed that the obtained PF exhibited highly improved mechanical properties (the compressive strength (485 kPa at a strain of 50%) was over 6 times higher compared with the borate cross-linked PF without chitosan and CPAM, and it was even higher than most of the reported cellulose-based porous materials). Also, the prepared PF has good performance on fire-retardance (hard to light), thermal insulation, antibiosis and sound absorption, due to the synergistic actions of borate, chitosan and CPAM. Additionally, spent liquor in preparing PF could be fully recycled, and thus this sustainable approach has potential for large-scale production of high-performance PF.

Thermoresponsive Nanostructures: From Mechano-Bactericidal Action to Bacteria Release

Overuse of antibiotics can increase the risk of notorious antibiotic resistance in bacteria, which has become a growing public health concern worldwide. Featured with the merit of mechanical rupture of bacterial cells, the bioinspired nanopillars are promising alternatives to antibiotics for combating bacterial infections while avoiding antibacterial resistance. However, the resident dead bacterial cells on nanopillars may greatly impair their bactericidal capability and ultimately impede their translational potential toward long-term applications. Here, we show that the functions of bactericidal nanopillars can be significantly broadened by developing a hybrid thermoresponsive polymer@nanopillar-structured surface, which retains all of the attributes of pristine nanopillars and adds one more: releasing dead bacteria. We fabricate this surface through coaxially decorating mechano-bactericidal ZnO nanopillars with thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) brushes. Combining the benefits of ZnO nanopillars and PNIPAAm chains, the antibacterial performances can be controllably regulated between ultrarobust mechano-bactericidal action (∼99%) and remarkable bacteria-releasing efficiency (∼98%). Notably, both the mechanical sterilization against the live bacteria and the controllable release for the pinned dead bacteria solely stem from physical actions, stimulating the exploration of intelligent structure-based bactericidal surfaces with persistent antibacterial properties without the risk of triggering drug resistance.

Synergistic antibacterial polyacrylonitrile/gelatin nanofibers coated with metal-organic frameworks for accelerating wound repair

Bacterial infections prolong the wound healing time and increase the suffering of patients, thus it is important to develop wound dressing that can inhibit bacterial infection. Herein, we use two methods including "doping method" and "secondary growth method" to prepare ZIF-8@gentamicin embedded in and coated on polyacrylonitrile/gelatin (PG) nanofibers, separately. Composite nanofibers prepared by the secondary growth method achieve higher drug loading than that of the doping method, and the release rate can be adjusted by pH. Simultaneously increasing drug loading and regulating its release rate are achieved in the secondary growth method, which cannot be achieved by the doping method. Furthermore, synergistic antibacterial property occurs in the composite nanofibers prepared by the secondary growth method, and gentamicin loaded on ZIF-8 promotes the antibacterial effect, which shows better antibacterial effect than the doping method. As a result, during the wound infection of mouse, composite nanofibers prepared by the secondary growth method exhibit a faster recovery effect than the doping method, which effectively shortened the wound healing time from 21 days to 16 days.

Bifunctional Smart Hydrogel Dressing with Strain Sensitivity and NIR-Responsive Performance

Smart response hydrogel has a broad application prospect in human health real-time monitoring due to its responses to a variety of stimuli. In this study, we developed a novel smart hydrogel dressing based on conductive MXene nanosheets and a temperature-sensitive PNIPAm polymer. γ-Methacryloxypropyltrimethoxysilane (KH570) was selected to functionalize the surface of MXene further to improve the interface compatibility between MXene and PNIPAm. Our prepared K-M/PNIPAm hydrogel was found to have a strain-sensitive property, as well as a respond to NIR phase change and volume change. When applied as a strain flexible sensor, this K-M/PNIPAm hydrogel exhibited a high strain sensitivity with a gauge factor (GF) of 4.491, a broad working strain range of ≈250%, a fast response of ∼160 ms, and good cycle stability (i.e., 3000 s at 20% strain). Besides, this K-M/PNIPAm hydrogel can be used as an efficient NIR light-controlled drug release carrier to achieve on-demand drug release. This work paved the way for the application of smart response hydrogel in human health real-time monitoring and NIR-controlled drug release functions.

Stretchable and Conductive Composite Structural Color Hydrogel Films as Bionic Electronic Skins

Electronic skins have received increasing attention in biomedical areas. Current efforts about electronic skins are focused on the development of multifunctional materials to improve their performance. Here, the authors propose a novel natural-synthetic polymers composite structural color hydrogel film with high stretchability, flexibility, conductivity, and superior self-reporting ability to construct ideal multiple-signal bionic electronic skins. The composite hydrogel film is prepared by using the mixture of polyacrylamide (PAM), silk fibroin (SF), poly(3,4-ethylenedioxythiophene):poly (4-styrene sulfonate) (PEDOT:PSS, PP), and graphene oxide (GO) to replicate colloidal crystal templates and construct inverse opal scaffolds, followed by subsequent acid treatment. Due to these specific structures and components, the resultant film is imparted with vivid structural color and high conductivity while retaining the composite hydrogel's original stretchability and flexibility. The authors demonstrate that the composite hydrogel film has obvious color variation and electromechanical properties during the stretching and bending process, which could thus be utilized as a multi-signal response electronic skin to realize real-time color sensing and electrical response during human motions. These features indicate that the proposed composite structural color hydrogel film can widen the practical value of bionic electronic skins.

A Novel N-Halamine Biocidal Nanofibrous Membrane for Chlorine Rechargeable Rapid Water Disinfection Applications

Disinfecting pathogenic contaminated water rapidly and effectively on sites is one of the critical challenges at point-of-use (POU) situations. Currently available technologies are still suffering from irreversible depletion of disinfectants, generation of toxic by-products, and potential biofouling problems. Herein, we developed a chlorine rechargeable biocidal nanofibrous membrane, poly(acrylonitrile-co-5-methyl-5-(4'-vinylphenyl)imidazolidine-2,4-dione) (P(AN-VAPH)), via a combination of a free radical copolymerization reaction and electrospun technology. The copolymer exhibits good electrospinnability and desirable mechanical properties. Also, the 5-methyl-5-(4'-vinylphenyl)imidazolidine-2,4-dione (VAPH) moieties containing unique hydantoin structures are able to be chlorinated and converted to halamine structures, enabling the P(AN-VAPH) nanofibrous membrane with rapid and durable biocidal activity. The chlorinated P(AN-VAPH) nanofibrous membranes showed intriguing features of unique 3D morphological structures with large specific surface area, good mechanical performance, rechargeable chlorination capacity (>5000 ppm), long-term durability, and desirable biocidal activity against both bacteria and viruses (>99.9999% within 2 min of contact). With these attributes, the chlorinated P(AN-VAPH) membranes demonstrated promising disinfecting efficiency against concentrated bacteria-contaminated water during direct filtration applications with superior killing capacity and high flowing flux (5000 L m^-2 h^-1).

Correlation between Protonation of Tailor-Made Polypiperazines and Endosomal Escape for Cytosolic Protein Delivery

Responsive polymers, which become protonated at decreasing pH, are considered a milestone in the development of synthetic cell entry vectors. Exact correlations between their properties and their ability to escape the endosome, however, often remain elusive due to hydrophobic interactions or limitations in the design of water-soluble materials with suitable basicity. Here, we present a series of well-defined, hydrophilic polypiperazines, where systematic variation of the amino moiety facilitates an unprecedented fine-tuning of the basicity or pK_a value within the physiologically relevant range (pH 6-7.4). Coincubation of HEK 293T cells with various probes, including small fluorophores or functioning proteins, revealed a rapid increase of endosomal release for polymers with pK_a values above 6.5 or 7 in serum-free or serum-containing media, respectively. Similarly, cytotoxic effects became severe at increased pK_a values (>7). Although the window for effective transport appears narrow, the discovered correlations offer a principal guideline for the design of effective polymers for endosomal escape.

Rational Design of an Antifungal Polyacrylamide Library with Reduced Host-Cell Toxicity

Life-threatening invasive fungal infections represent an urgent threat to human health worldwide. The limited set of antifungal drugs has critical constraints such as resistance development and/or adverse side effects. One approach to overcome these limitations is to mimic naturally occurring antifungal peptides called defensins. Inspired by their advantageous amphiphilic properties, a library of 35 synthetic, linear, ternary polyacrylamides was prepared by controlled/living radical polymerization. The effect of the degree of polymerization (20, 40, and 100) and varying hydrophobic functionalities (branched, linear, cyclic, or aromatic differing in their number of carbons) on their antifungal activity was investigated. Short copolymers with a calculated log P of ∼1.5 revealed optimal activity against the major human fungal pathogen Candida albicans and other pathogenic fungal species with limited toxicity to mammalian host cells (red blood cells and fibroblasts). Remarkably, selected copolymers outperformed the commercial antifungal drug amphotericin B, with respect to the therapeutic index, highlighting their potential as novel antifungal compounds.

High-Strength, Strongly Bonded Nanocomposite Hydrogels for Cartilage Repair

Polyacrylamide-based hydrogels are widely used as potential candidates for cartilage replacement. However, their bioapplicability is sternly hampered due to their limited mechanical strength and puncture resistance. In the present work, the strength of polyacrylamide (PAM) hydrogels was increased using titanium oxide (TiO₂) and carbon nanotubes (CNTs) separately and a combination of TiO₂ with CNTs in a PAM matrix, which was interlinked by the bonding between nanoparticles and polymers with the deployment of density functional theory (DFT) approach. The synergistic effect and strong interfacial bonding of TiO₂ and CNT nanoparticles with PAM are attributed to high compressive strength, elastic modulus (>0.43 and 2.340 MPa, respectively), and puncture resistance (estimated using the needle insertion test) for the PAM-TiO₂-CNT hydrogel. The PAM-TiO₂-CNT composite hydrogel revealed a significant self-healing phenomenon along with a sign toward the bioactivity and cytocompatibility by forming the apatite crystals in simulated body fluid as well as showing a cell viability of ∼99%, respectively. Furthermore, for new insights on interfacial bonding and structural and electronic features involved in the hydrogels, DFT was used. The PAM-TiO₂-CNT composite model, constructed by two interfaces (PAM-TiO₂ and PAM-CNT), was stabilized by H-bonding and van der Waals-type interactions. Employing the NCI plot, HOMO-LUMO gap, and natural population analysis tools, the PAM-TiO₂-CNT composite has been found to be most stable. Therefore, the prepared polyacrylamide hydrogels in combination with the TiO₂ and CNT can be a remarkable nanocomposite hydrogel for cartilage repair applications.

Photodegradable Polyacrylamide Gels for Dynamic Control of Cell Functions

Cross-linked polyacrylamide hydrogels are commonly used in biotechnology and cell culture applications due to advantageous properties, such as the precise control of material stiffness and the attachment of cell adhesive ligands. However, the chemical and physical properties of polyacrylamide gels cannot be altered once fabricated. Here, we develop a photodegradable polyacrylamide gel system that allows for a dynamic control of polyacrylamide gel stiffness with exposure to light. Photodegradable polyacrylamide hydrogel networks are produced by copolymerizing acrylamide and a photocleavable ortho-nitrobenzyl (o-NB) bis-acrylate cross-linker. When the hydrogels are exposed to light, the o-NB cross-links cleave and the stiffness of the photodegradable polyacrylamide gels decreases. Further examination of the effect of dynamic stiffness changes on cell behavior reveals that in situ softening of the culture substrate leads to changes in cell behavior that are not observed when cells are cultured on presoftened gels, indicating that both dynamic and static mechanical environments influence cell fate. Notably, we observe significant changes in nuclear localization of YAP and cytoskeletal organization after in situ softening; these changes further depend on the type and concentration of cell adhesive proteins attached to the gel surface. By incorporating the simplicity and well-established protocols of standard polyacrylamide gel fabrication with the dynamic control of photodegradable systems, we can enhance the capability of polyacrylamide gels, thereby enabling cell biologists and engineers to study more complex cellular behaviors that were previously inaccessible using regular polyacrylamide gels.

Seven-year efficacy and safety outcomes of Bulkamid for the treatment of stress urinary incontinence

AIMS

Bulking agents are a minimally invasive treatment option for women with stress urinary incontinence (SUI) or stress-predominant mixed urinary incontinence (MUI). The aim of this study was to evaluate long-term efficacy and safety following treatment with Bulkamid as a primary procedure for SUI or stress-predominant MUI.

METHODS

This was an Institutional Review Board-approved single-center retrospective study of female patients with SUI or stress-predominant MUI who had undergone injection with Bulkamid since 2005 and had completed 7 years of follow up. The primary endpoint was patient satisfaction measured on a four-point scale as cured, improved, unchanged, or worse. Secondary outcomes included the number of incontinence pads used, International Consultation on Incontinence Questionnaire-Short Form (ICIQ-UI SF) scores, Visual Analog Scale Quality of Life (VAS QoL), reinjection rates, and perioperative and postoperative complications.

RESULTS

A total of 1,200 patients were treated with Bulkamid since 2005 and of these, 388 (32.3%) had completed 7 years of follow-up. A total of 67.1% of the patients reported feeling cured or improved if Bulkamid was a primary procedure, 11.1% reported no change, and 2.3% reported worsening of incontinence. A total of 19.5% of patients received a subsequent other incontinence procedure. The ICIQ-UI SF was reduced by 8.6 points. VAS QoL improved by a mean of 4.3 points. Postoperative complications were transient. Prolonged bladder emptying time was reported in 15.3% of patients and urinary tract infection in 3.5%.

CONCLUSIONS

Bulkamid injections are an effective and safe first-line treatment option for women with SUI or stress-predominant MUI providing durable outcomes at 7 years.

Preparation and characterization of human keratinocyte-fibroblast cell sheets constructed using PNIAM-co-AM grafted surfaces for burn wound healing

Autologous skin grafting, the standard treatment for severe burns, is sometimes not possible due to the limited available skin surfaces for the procedure. With advances in tissue engineering, various cell-based skin substitutes have been developed to serve as skin replacements and to promote tissue regeneration and healing. In this work, we propose the use of cell sheet technology to fabricate keratinocyte-fibroblast tissue constructs from the temperature-responsive poly(N-isoproprylacrylamide-co-acrylamide) (PNIAM-co-AM) grafted surfaces for the treatment of burn wounds. The characteristics of the human keratinocyte and fibroblast cell sheets harvested using PNIAM-co-AM grafted surfaces were similar to those cell sheets detached from the commercially-available UpCell^TM plates. Upon lowering the incubation temperature, confluent keratinocytes and fibroblasts could be detached as intact sheets, consisting of biologically active cells, as indicated by their high cell viability and their reattachment, migratory, and proliferative activities. A histological analysis of the stratified keratinocyte-fibroblast cell sheets revealed the evidence of cell migration and tissue reorganization to form two distinct epidermal and dermal layers, quite similar to the skin tissue's structure. In addition, the keratinocyte-fibroblast sheets could synthesize and release significant amounts of essential cytokines and growth factors involved in regulating the wound healing process, including IL-1α, IL-6, TNF-α, VEGF, and bFGF, implying the therapeutic effect of these cell sheets, which could be beneficial to accelerate tissue repair and regeneration, leading to faster wound healing.

Potential of antimicrobial topical gel with synthesized biogenic silver nanoparticle using Rhodomyrtus tomentosa leaf extract and silk sericin

OBJECTIVE

Silver nanoparticles synthesized using Rhodomyrtus tomentosa leaf extract and silk sericin were used to functionalize carbopol 940 gel for topical applications.

RESULTS

UV-vis spectra presented surface plasmon resonance at 426 nm, transmission electron microscopy revealed that nanoparticles were spherical with an average size of 25-50 nm. X-ray diffraction presented crystalline silver nanoparticles with zeta potential of ≈ - 30 mV. FTIR spectra showed a reduction of silver nitrate indicated by the shift in -OH at 2958 cm^-1. The silver nanoparticle demonstrated broad-spectrum antimicrobial activity against Gram-positive, Gram-negative and fungi with MIC ranging between 0.26 and 2.10 μg mL^-1, respectively. MIC of hydrogel ranged between 1.05-2.10 μg mL^-1 with cell viability of 89%. Spreadability and extrudability of gel were 9.3 ± 0.85 s and 19.85 ± 0.03%, respectively with first order of fickian diffusion.

CONCLUSIONS

The silver nanoparticle gel exhibited an effective antimicrobial property, hence can be exploited for topical applications.

Smart, Photothermally Activated, Antibacterial Surfaces with Thermally Triggered Bacteria-Releasing Properties

The development of effective antibacterial surfaces to prevent the attachment of pathogenic bacteria and subsequent bacterial colonization and biofilm formation is critically important for medical devices and public hygiene products. In the work reported herein, a smart antibacterial hybrid film based on tannic acid/Fe³⁺ ion (TA/Fe) complex and poly(N-isopropylacrylamide) (PNIPAAm) is deposited on diverse substrates. This surface is shown to have bacteria-killing and bacteria-releasing properties based on, respectively, near-infrared photothermal activation and subsequent cooling. The TA/Fe complex has three roles in this system: (i) as a universal adhesive "anchor" for surface modification, (ii) as a high-efficiency photothermal agent for ablation of attached bacteria (including multidrug resistant bacteria), and (iii) as a robust linker for immobilization of NH₂-terminated PNIPAAm via either Michael addition or Schiff base formation. Moreover, because of the thermoresponsive properties of the immobilized PNIPAAm, almost all of the killed bacteria and other debris can be removed from the surface simply by lowering the temperature. It is shown that this hybrid film can maintain good antibacterial performance after being used for multiple "kill-and-release" cycles and can be applied to various substrates regardless of surface chemistry or topography, thus providing a broadly applicable, simple, and reliable solution to the problems associated with surface-attached bacteria in various healthcare applications.

Antioxidant, anti-inflammatory and healing potential of ethyl acetate fraction of Bauhinia ungulata L. (Fabaceae) on in vitro and in vivo wound model

The present work aimed to investigate the antioxidant, anti-inflammatory and wound healing potential of ethyl acetate fraction from Bauhinia ungulata L. (FABU) on in vitro and in vivo models. Wound healing assay using human lung adenocarcinoma A549 cell line was employed to evaluate the ability of FABU in modulating cell migration. In addition, a surgical wound model in C57BL/6 mice was used to study the healing potential of FABU incorporated into gel carbomer 940 (Carbopol®). Evaluation of lipid peroxidation, inflammatory and anti-inflammatory mediator gene expression, rate of wound closure, and histological analysis were done. FABU significantly reduced the gap area in in vitro wound healing assay, 24 h after treatment. In the animal model, FABU at 0.5% topically applied once-daily for 5 days to the surgical wounds significantly reduced the lesion area. Moreover, it significantly decreased the levels of lipid peroxidation in the lesions and decreased the relative gene expression levels of IL-1β and TNF-α in the injured region. In conclusion, our study suggests that Bauhinia ungulata can effectively promote the wound healing, probably by regulating the inflammatory environment during the early stages of the process.

Is it necessary to pre-treat Dentine before GIC Restorations? Evidence from an in Vitro Study

The aim of this study was to assess the influence of different pre-treatment approaches on glass ionomer cement (GIC) bond strength (BS) to dentine. Sixty bovine incisors were allocated into six groups according to substrate - sound or caries-affected dentine; and substrate pre-treatment approach - no conditioning (control), polyacrylic acid for 10 s and phosphoric acid for 7 s. Teeth in the caries-affected dentine group were previously submitted to cariogenic pH-cycling challenge. After dentine pre-treatment, according to experimental groups, polyethylene tubes were placed on flat dentine surfaces and filled with GIC. Teeth were stored in distilled water for 24 h at 37 °C and then submitted to microshear test (0.5 mm/min). Failure pattern analysis was performed under stereomicroscope (400x). Data were analysed using two-way ANOVA and Tukey's test (α=5%). Statistically significant differences were found for the pre-treatment approach, regardless of substrate (p<0.001). The polyacrylic acid group and control group had similar BS values, and were both better than the phosphoric acid group. In general, GIC had better bonding performance in sound dentine than in caries-affected dentine. In conclusion, dentine pre-treatment with polyacrylic acid did not improve the performance of GIC restoration on clinically relevant substrates.

Evaluation of Microbial Adhesion and Biofilm Formation on Nano-Structured and Nano-Coated Ortho-Prosthetic Materials by a Dynamic Model

The bio-engineering technologies of medical devices through nano-structuring and coating was recently proposed to improve biocompatibility and to reduce microbial adhesion in the prevention of implantable device-related infections. Our aim was to evaluate the ability of new nano-structured and coated materials to prevent the adhesion and biofilm formation, according to the American Standard Test Method ASTM-E2647-13. The materials composition was determined by X-ray Fluorescence and Laser Induced Breakdown Spectroscopy. Silver release was evaluated by Inductively Coupled Plasma Mass Spectrometry analysis. The gene expression levels of the Quorum Sensing Las and Rhl system were evaluated by the ΔΔCt method. The Log bacterial density (Log CFU/cm²) on TiAl6V4 was 4.41 ± 0.76 and 4.63 ± 1.01 on TiAl6V4-AgNPs compared to 2.57 ± 0.70 on CoCr and 2.73 ± 0.61 on CoCr-AgNPs (P < 0.0001, A.N.O.V.A.- one way test). The silver release was found to be equal to 17.8 ± 0.2 µg/L after the batch phase and 1.3 ± 0.1 µg/L during continuous flow. The rhlR gene resulted in a 2.70-fold increased expression in biofilm growth on the silver nanoparticles (AgNPs) coating. In conclusion, CoCr showed a greater ability to reduce microbial adhesion, independently of the AgNPs coating. The silver release resulted in promoting the up-regulation of the Rhl system. Further investigation should be conducted to optimize the effectiveness of the coating.

Shape-morphing living composites

This work establishes a means to exploit genetic networks to create living synthetic composites that change shape in response to specific biochemical or physical stimuli. Baker's yeast embedded in a hydrogel forms a responsive material where cellular proliferation leads to a controllable increase in the composite volume of up to 400%. Genetic manipulation of the yeast enables composites where volume change on exposure to l-histidine is 14× higher than volume change when exposed to d-histidine or other amino acids. By encoding an optogenetic switch into the yeast, spatiotemporally controlled shape change is induced with pulses of dim blue light (2.7 mW/cm2). These living, shape-changing materials may enable sensors or medical devices that respond to highly specific cues found within a biological milieu.

Importance of Polyacrylamide Hydrogel Diverse Chains and Cross-Linking Density for Cell Proliferation, Aging, and Death

Diverse chains and cross-linking density of polymers are important for cell proliferation, aging, and death. In this study, by controlling the component ratio of N,N'-methylenebisacrylamide (Bis)/acrylamide (Acr), we prepared polyacrylamide (PAM) hydrogels with three different polymer structures using ultraviolet irradiation. Moreover, we quantified their Flory's cross-linking densities, gel concentrations, and mechanical properties and evaluated their influence to HL-7702 liver cell behavior and metabolism. Results showed that PAM hydrogel at a ratio of Bis/Acr = 1:50 (Acr-50) owned the highest cross-linking density (0.04), which provided abundant binding sites for cell adhesion and allowed for rapid cell proliferation. On the basis of the binding sites, cells had strong traction interaction from fibrillate adhesion with the polymers, allowed easy cell migration, and induced the living cell aggregations with a diameter of 800 μm. Cells in aggregation exhibited healthy cell phenotypes and functions, and also the mitosis of the cells in aggregation is exactly the same with the cells in tissue. It is concluded that cell proliferation, aging, and death can be controlled by adjusting the cross-linking density and diverse chains of matrix hydrogels. This work will be helpful to design new functional soft biomaterials for tissue regeneration in the future.

Construction of Biofunctionalized Anisotropic Hydrogel Micropatterns and Their Effect on Schwann Cell Behavior in Peripheral Nerve Regeneration

Hydrogels have promising application in tissue regeneration due to their excellent physicochemical and biocompatible properties, whereas anisotropic micropatterns are been proven to directionally induce cell alignment and accelerate cell migration. However, an effect of biofunctionalized anisotropic hydrogel micropatterns on nerve regeneration has rarely been reported. In this study, the anisotropic polyacrylamide (PAM) hydrogel micropatterns with aligned ridge/groove structures were first prepared via in situ free radical polymerization and micromolding, and then biofunctionalized using YIGSR peptide for better promoting cell growth. The morphology, swelling ratio, wettability, mechanical properties, and stability of the prepared hydrogel were characterized. The successful immobilization of YIGSR peptide on the PAM hydrogel was monitored using FTIR, immunofluorescence staining, and ELISA. The effects on adhesion, directional growth, and biological function of Schwann cells were evaluated. The results displayed that the anisotropic PAM hydrogel micropatterns with inner porous structure possessed good stability, swelling, and mechanical properties. The YIGSR peptide could be well immobilized on hydrogel micropatterns with a percentage of 62.6%. The biofunctionalized anisotropic hydrogel micropatterns could effectively regulate the orientation growth of Schwann cells, and obviously up-regulate BDNF (40%) and β-actin (50%) expression compared with single hydrogel micropatterns, without negatively affecting the normal secretion of neurotropic factors by Schwann cells. To the best of our knowledge, this is the first time to study the construction and effect of biofunctionalized anisotropic hydrogel micropatterns on nerve regeneration, which may provide an experimental and theoretical basis for the design and development of artificial implants for nerve regeneration application.

Effects of surface pre-reacted glass-ionomer (S-PRG) eluate on Candida spp.: antifungal activity, anti-biofilm properties, and protective effects on Galleria mellonella against C. albicans infection

Surface pre-reacted glass-ionomer (S-PRG) is a bioactive filler produced by PRG technology, which is applied to various dental materials. The inhibitory effects of S-PRG eluate against Candida, the most common fungal oral pathogen, were investigated. Minimum inhibitory concentrations (MIC) and anti-biofilm activities were tested against Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis. For the in vivo study, Galleria mellonella was used as a model to evaluate the effects of S-PRG on toxicity, hemocyte counts and candidiasis. The MIC of S-PRG ranged from 5 to 40% (v/v). S-PRG eluate exhibited anti-biofilm activity for all the Candida species tested. Furthermore, injection of S-PRG eluate into G. mellonella was not toxic to the larvae and protected G. mellonella against experimental candidiasis. In addition, S-PRG eluate inhibited biofilm formation by C. albicans, C. glabrata, C. krusei, and C. tropicalis and exerted protective effects on G. mellonella against experimental candidiasis in vivo.

Influence of Hydrolyzed Polyacrylamide Hydrogel Stiffness on Podocyte Morphology, Phenotype, and Mechanical Properties

Chronic kidney disease is characterized by a gradual decline in renal function that progresses toward end-stage renal disease. Podocytes are highly specialized glomerular epithelial cells which form with the glomerular basement membrane (GBM) and capillary endothelium the glomerular filtration barrier. GBM is an extracellular matrix (ECM) that acts as a mechanical support and provides biophysical signals that control normal podocytes behavior in the process of glomerular filtration. Thus, the ECM stiffness represents an essential characteristic that controls podocyte function. Hydrolyzed Polyacrylamide (PAAm) hydrogels are smart polyelectrolyte materials. Their biophysical properties can be tuned as desired to mimic the natural ECM. Therefore, these hydrogels are investigated as new ECM-like constructs to engineer a podocyte-like basement membrane that forms with cultured human podocytes a functional glomerular-like filtration barrier. Such ECM-like PAAm hydrogel construct will provide unique opportunity to reveal podocyte cell biological responses in an in vivo-like setting by controlling the physical properties of the PAAm membranes. In this work, Hydrolyzed PAAm scaffolds having different stiffness ranging between 0.6-44 kPa are prepared. The correlation between the hydrogel structural and mechanical properties and Podocyte morphology, elasticity, cytoskeleton reorganization, and podocin expression is evaluated. Results show that hydrolyzed PAAm hydrogels promote good cell adhesion and growth and are suitable materials for the development of future 3D smart scaffolds. In addition, the hydrogel properties can be easily modulated over a wide physiological range by controlling the cross-linker concentration. Finally, tuning the hydrogel properties is an effective strategy to control the cells function. This work addressed the complexity of podocytes behavior which will further enhance our knowledge to develop a kidney-on-chip model much needed in kidney function studies in both healthy and diseased states.

Synthetic networks with tunable responsiveness, biodegradation, and molecular recognition for precision medicine applications

Formulations and devices for precision medicine applications must be tunable and multiresponsive to treat heterogeneous patient populations in a calibrated and individual manner. We engineered modular poly(acrylamide-co-methacrylic acid) copolymers, cross-linked into multiresponsive nanogels with either a nondegradable or degradable disulfide cross-linker, that were customized via orthogonal chemistries to target biomarkers of an individual patient's disease or deliver multiple therapeutic modalities. Upon modification with functional small molecules, peptides, or proteins, these nanomaterials delivered methylene blue with environmental responsiveness, transduced visible light for photothermal therapy, acted as a functional enzyme, or promoted uptake by cells. In addition to quantifying the nanogels' composition, physicochemical characteristics, and cytotoxicity, we used a QCM-D method for characterizing nanomaterial degradation and a high-throughput assay for cellular uptake. In conclusion, we generated a tunable nanogel composition for precision medicine applications and new quantitative protocols for assessing the bioactivity of similar platforms.

An oral drug delivery system with programmed drug release and imaging properties for orthotopic colon cancer therapy

Oral drug delivery systems (ODDSs) have attracted considerable attention in relation to orthotopic colon cancer therapy due to certain popular advantages. Unfortunately, their clinical applications are generally limited by the side-effects caused by systemic drug exposure and poor real-time monitoring capabilities. Inspired by the characteristics of pH changes of the gastrointestinal tract (GIT) and specific enzymes secreted by the colonic microflora, we anchored polyacrylic acid (PAA) and chitosan (CS) on Gd3+-doped mesoporous hydroxyapatite nanoparticles (Gd-MHAp NPs) to realize programmed drug release and magnetic resonance imaging (MRI) at the tumor sites. In particular, the grafted PAA, as a pH-responsive switch, could effect controlled drug release in the colon. Further, CS is functionalized as the enzyme-sensitive moiety, which could be degraded by β-glycosidase in the colon. Gadolinium is a paramagnetic lanthanide element used in chelates, working as a contrast medium agent for an MRI system. Interestingly, after oral administration, CS and PAA could protect the drug-loaded nanoparticles (NPs) against variable physiological conditions in the GIT, allowing the drug to reach the colon tumor sites, preventing premature drug release. Enhanced drug concentrations at the colon tumor sites were achieved via this programmed drug release, which subsequently ameliorated the therapeutic effect. In addition, encapsulating both chemotherapeutic (5-fluorouracil, 5-FU) and targeted therapy drug (gefitinib, Gef) within Gd-MHAp NPs produced a synergistic therapeutic effect. In summary, this study demonstrated that such a novel drug system (Gd-MHAp/5-FU/Gef/CS/PAA NPs) could protect, transport, and program drug release locally within the colonic environment; further, this system exhibited a worthwhile therapeutic effect, providing a promising novel treatment strategy for orthotopic colon cancer.

Polyacrylate/polyacrylate-PEG biomaterials obtained by high internal phase emulsions (HIPEs) with tailorable drug release and effective mechanical and biological properties

The paper focuses on the preparation of polyacrylate based biomaterials designed as patches for dermal/transdermal drug delivery using materials obtained by the high internal phase emulsion (HIPE) technique. In particular, butyl acrylate and glycidyl methacrylate were selected, respectively, as backbone and functional monomer while two different crosslinkers, bifunctional or trifunctional, were used to form the covalent network. The influence of PEG on the main properties of the materials was also investigated. The obtained materials show a characteristic and interconnected internal structure as confirmed by SEM studies. By an industrial point of view, an interesting feature of this system is that it can be shaped as needed, in any form and thickness. The physiochemically characterized materials showed a tailorable curcumin (model of hydrophobic drugs) drug release, effective mechanical properties and cell viability and resulted neither pro nor anti-angiogenic as demonstrated in vivo by the chick embryo choriallantoic membrane (CAM) assay. Based on these results, the obtained polyHIPEs could be proposed as devices for dermal/transdermal drug delivery and/or for the direct application on wounded skin.

Thermosensitive Display of Carbohydrate Ligands on Microgels for Switchable Binding of Proteins and Bacteria

The synthesis of carbohydrate-functionalized thermosensitive poly(N-isopropylacrylamide) microgels and their ability to bind carbohydrate-binding pathogens upon temperature switch are reported. It is found that the microgels' binding affinity is increased above their lower critical solution temperature (LCST), enabling thermo-triggerable capture of pathogens. Here, a series of microgels with comparatively low mannose functionalization degrees below 1 mol % is achieved by a single polymerization step. Upon increase in mannose density, the microgel size increases, and the LCST decreases to 26 °C. Clustering with concanavalin A indicated that binding affinity is enhanced by a higher mannose content and by raising the temperature above the LCST. Binding studies with Escherichia coli confirm stronger specific interactions above the LCST and formation of mechanically stable aggregates enabling efficient separation of E. coli by filtration. For small incubation times above the LCST, the microgels' potential to release pathogens again below the LCST is confirmed also. Compared to existing switchable scaffolds, microgels nearly entirely composed of a thermosensitive material undergo a large change in volume, which allows them to drastically vary the density of ligands to switch between capture and release. This straightforward yet novel approach is likely compatible with a broad range of bioactive ligands. Therefore, thermosensitive microgels represent a promising platform for the specific capture or release of cells or pathogens.

Paramagnetic Clusters of Mn3(O2CCH3)6(Bpy)2 in Polyacrylamide Nanobeads as a New Design Approach to a T1- T2 Multimodal Magnetic Resonance Imaging Contrast Agent

There is an increasing need for gadolinium-free magnetic resonance imaging (MRI) contrast agents, particularly for patients suffering from chronic kidney disease. Using a cluster-nanocarrier combination, we have identified a novel approach to the design of biomedical nanomaterials and report here the criteria for the cluster and the nanocarrier and the advantages of this combination. We have investigated the relaxivity of the following manganese oxo clusters: the parent cluster Mn₃(O₂CCH₃)₆(Bpy)₂ (1) where Bpy = 2,2'-bipyridine and three new analogs, Mn₃(O₂CC₆H₄CH═CH₂)₆(Bpy)₂ (2), Mn₃(O₂CC(CH₃)═CH₂)₆(Bpy)₂ (3), and Mn₃O(O₂CCH₃)₆(Pyr)₂ (4) where Pyr = pyridine. The parent cluster, Mn₃(O₂CCH₃)₆(Bpy)₂ (1), had impressive relaxivity ( r₁ = 6.9 mM^-1 s^-1, r₂ = 125 mM^-1 s^-1) and was found to be the most amenable for the synthesis of cluster-nanocarrier nanobeads. Using the inverse miniemulsion polymerization technique (1) in combination with the hydrophilic monomer acrylamide, we synthesized nanobeads (∼125 nm diameter) with homogeneously dispersed clusters within the polyacrylamide matrix (termed Mn₃Bpy-PAm). The nanobeads were surface-modified by co-polymerization with an amine-functionalized monomer. This enabled various postsynthetic modifications, for example, to attach a near-IR dye, Cyanine7, as well as a targeting agent. When evaluated as a potential multimodal MRI contrast agent, high relaxivity and contrast were observed with r₁ = 54.4 mM^-1 s^-1 and r₂ = 144 mM^-1 s^-1, surpassing T₁ relaxivity of clinically used Gd-DTPA chelates as well as comparable T₂ relaxivity to iron oxide microspheres. Physicochemical properties, cellular uptake, and impacts on cell viability were also investigated.

Material stiffness influences the polarization state, function and migration mode of macrophages

Biomaterial implantation is followed by an inflammatory cascade dominated by macrophages, which determine implant acceptance or rejection through pro- and anti-inflammatory polarization states (Anderson et al., 2008; Brown and Badylak, 2013). It is known that chemical signals such as bacterial endotoxins and cytokines (IL4) can direct macrophage polarization (Mantovani et al., 2004); however, recent evidence implicates biophysical cues in this process (McWhorter et al., 2015; Patel et al., 2012). Here we report that THP-1 derived macrophages cultured on collagen-coated polyacrylamide gels of varying stiffness adapt their polarization state, functional roles and migration mode according to the stiffness of the underlying substrate. Through gene expression and protein secretion analysis, we show that stiff polyacrylamide gels (323 kPa) prime macrophages towards a pro-inflammatory phenotype with impaired phagocytosis in macrophages, while soft (11 kPa) and medium (88 kPa) stiffness gels prime cells towards an anti-inflammatory, highly phagocytic phenotype. Furthermore, we show that stiffness dictates the migration mode of macrophages; on soft and medium stiffness gels, cells display Rho-A kinase (ROCK)-dependent, podosome-independent fast amoeboid migration and on stiff gels they adopt a ROCK-independent, podosome-dependent slow mesenchymal migration mode. We also provide a mechanistic insight into this process by showing that the anti-inflammatory property of macrophages on soft and medium gels is ROCK-dependent and independent of the ligand presented to them. Together, our results demonstrate that macrophages adapt their polarization, function and migration mode in response to the stiffness of the underlying substrate and suggest that biomaterial stiffness is capable of directing macrophage behaviour independent of the biochemical cues being presented to them. The results from this study establish an important role for substrate stiffness in directing macrophage behaviour, and will lead to the design of immuno-informed biomaterials that are capable of modulating the macrophage response after implantation. STATEMENT OF SIGNIFICANCE: Biomaterial implantation is followed by an inflammatory cascade dominated by macrophages, which determine implant acceptance or rejection through pro- and anti-inflammatory polarization states. It is known that chemical signals can direct macrophage polarization; however, recent evidence implicates biophysical cues in this process. Here we report that macrophages cultured on gels of varying stiffness adapt their polarization state, functional roles and migration mode according to the stiffness of the underlying substrate. The results from this study establish an important role for substrate stiffness in directing macrophage behaviour, and will lead to the design of immuno-informed biomaterials that are capable of modulating the macrophage response after implantation.

Hypoxia impacts human MSC response to substrate stiffness during chondrogenic differentiation

Tissue engineering strategies often aim to direct tissue formation by mimicking conditions progenitor cells experience within native tissues. For example, to create cartilage in vitro, researchers often aim to replicate the biochemical and mechanical milieu cells experience during cartilage formation in the developing limb bud. This includes stimulating progenitors with TGF-β1/3, culturing under hypoxic conditions, and regulating mechanosensory pathways using biomaterials that control substrate stiffness and/or cell shape. However, as progenitors differentiate down the chondrogenic lineage, the pathways that regulate their responses to mechanotransduction, hypoxia and TGF-β may not act independently, but rather also impact one another, influencing overall cell response. Here, to better understand hypoxia's influence on mechanoregulatory-mediated chondrogenesis, we cultured human marrow stromal/mesenchymal stem cells (hMSC) on soft (0.167 kPa) or stiff (49.6 kPa) polyacrylamide hydrogels in chondrogenic medium containing TGF-β3. We then compared cell morphology, phosphorylated myosin light chain 2 staining, and chondrogenic gene expression under normoxic and hypoxic conditions, in the presence and absence of pharmacological inhibition of cytoskeletal tension. We show that on soft compared to stiff substrates, hypoxia prompts hMSC to adopt more spread morphologies, assemble in compact mesenchymal condensation-like colonies, and upregulate NCAM expression, and that inhibition of cytoskeletal tension negates hypoxia-mediated upregulation of molecular markers of chondrogenesis, including COL2A1 and SOX9. Taken together, our findings support a role for hypoxia in regulating hMSC morphology, cytoskeletal tension and chondrogenesis, and that hypoxia's effects are modulated, at least in part, by mechanosensitive pathways. Our insights into how hypoxia impacts mechanoregulation of chondrogenesis in hMSC may improve strategies to develop tissue engineered cartilage. STATEMENT OF SIGNIFICANCE: Cartilage tissue engineering strategies often aim to drive progenitor cell differentiation by replicating the local environment of the native tissue, including by regulating oxygen concentration and mechanical stiffness. However, the pathways that regulate cellular responses to mechanotransduction and hypoxia may not act independently, but rather also impact one another. Here, we show that on soft, but not stiff surfaces, hypoxia impacts human MSC (hMSC) morphology and colony formation, and inhibition of cytoskeletal tension negates the hypoxia-mediated upregulation of molecular markers of chondrogenesis. These observations suggest that hypoxia's effects during hMSC chondrogenesis are modulated, at least in part, by mechanosensitive pathways, and may impact strategies to develop scaffolds for cartilage tissue engineering, as hypoxia's chondrogenic effects may be enhanced on soft materials.

Two-in-One Platform for High-Efficiency Intracellular Delivery and Cell Harvest: When a Photothermal Agent Meets a Thermoresponsive Polymer

Efficient intracellular delivery of exogenous macromolecules is a key operation in biological research and for clinical applications. Moreover, under particular in vitro or ex vivo conditions, harvesting the engineered cells that maintain good viability is also important. However, none of the methods currently available is truly satisfactory in all respects. Herein, a "two-in-one" platform based on a polydopamine/poly( N-isopropylacrylamide) (PDA/PNIPAAm) hybrid film is developed, showing high efficiency in both cargo delivery and cell harvest without compromising cell viability. Due to the strong photothermal effect of PDA in response to near-infrared irradiation, this film can deliver diverse molecules to a number of cell types (including three hard-to-transfect cells) with an efficiency of ∼99% via membrane-disruption mechanism. Moreover, due to the thermoresponsive properties of PNIPAAm, the cells are harvested from the film without compromising viability by simply decreasing the temperature. A proof-of-concept experiment demonstrates that, using this platform, "recalcitrant" endothelial cells can be transfected by the functional ZNF580 gene and the harvested transfected cells can be recultured with high retention of viability and improved migration. In general, this "two-in-one" platform provides a reliable, universally applicable approach for both intracellular delivery and cell harvest in a highly efficient and nondestructive way, with great potential for use in a wide range of biomedical applications.

A strong, tough, and osteoconductive hydroxyapatite mineralized polyacrylamide/dextran hydrogel for bone tissue regeneration

The design of hydrogels with adequate mechanical properties and excellent bioactivity, osteoconductivity, and capacity for osseointegration is essential to bone repair and regeneration. However, it is challenging to integrate all these properties into one bone scaffold. Herein, we developed a strong, tough, osteoconductive hydrogel by a facile one-step micellar copolymerization of acrylamide and urethacrylate dextran (Dex-U), followed by the in situ mineralization of hydroxyapatite (HAp) nanocrystals. We show that the soft, flexible, and hydrophobically associated polyacrylamide (PAAm) network is strengthened by the stiff crosslinked Dex-U phase, and that the mineralized HAp simultaneously improves the mechanical properties and osteoconductivity. The obtained HAp mineralized PAAm/Dex-U hydrogel (HAp-PADH) has extremely high compressive strength (6.5 MPa) and enhanced fracture resistance (over 2300 J m^-2), as compared with pure PAAm hydrogels. In vitro, we show that the mineralized HAp layer promotes the adhesion and proliferation of osteoblasts, and effectively stimulates osteogenic differentiation. Through the in vivo evaluation of hydrogels in a femoral condyle defect rabbit model, we show regeneration of a highly mineralized bone tissue and direct bonding to the HAp-PADH interface. These findings confirm the excellent osteoconductivity and osseointegration ability of fabricated HAp-PADH. The present HAp-PADH, with its superior mechanical properties and excellent osteoconductivity, should have great potential for bone repair and regeneration. STATEMENT OF SIGNIFICANCE: We developed a strong, tough, and osteoconductive hydrogel by a facile one-step micellar copolymerization of acrylamide and urethane methacrylate dextran (Dex-U), followed by the in situ mineralization of hydroxyapatite (HAp) nanocrystals. The hydrophobic micellar copolymerization and introduction of the stiff crosslinked Dex-U phase endowed the soft polyacrylamide (PAAm) network with enhanced strength and toughness. The in situ mineralized HAp nanocrystals on the hydrogels further improved the mechanical properties of the hydrogels and promoted osteogenic differentiation of cells. Mechanical tests together with in vitro and in vivo evaluations confirmed that the HAp mineralized PAAm/Dex-U hydrogel (HAp-PADH) achieved a combination of superior mechanical properties and excellent osseointegration, and thus may offer a promising candidate for bone repair and regeneration.

Effect of Polyacrylamide/Attapulgite Composite on Foraging Behaviors of Formosan Subterranean Termites (Blattodea: Rhinotermitidae)

Moisture conditions of food and soil are essential for the survival and foraging activities of subterranean termites. Polyacrylamide/attapulgite composite is a water-retaining agent that has been applied to increase moisture of agricultural soils. We hypothesize that polyacrylamide/attapulgite composite may increase the moisture of bait matrixes and soil surrounding baiting containers and therefore attract termites and increase their foraging activities. In the present study, aggregation and feeding preferences, survivorship, body water percentage, and wood consumption of Formosan subterranean termites, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), were investigated when responding to polyacrylamide/attapulgite composite that was buried within soil (substrate) or filled in the void volume of baiting containers. Two-choice tests showed that termites consumed significantly more wood when polyacrylamide/attapulgite composite was buried within dry soil (27%-moisture) than the controls (no polyacrylamide/attapulgite composite was provided). However, polyacrylamide/attapulgite composite buried within wet soil (54%-moisture) did not significantly affect foraging behaviors of termites. Multiple-choice tests showed no aggregation or feeding preference of termites in the baiting containers filled with polyacrylamide/attapulgite composite compared with the soil-filled or unfilled ones, whenever the substrate was dry or wet. No-choice tests showed that the presence of polyacrylamide/attapulgite composite (buried within soil or filled in baiting containers) significantly increased wood consumption and body water percentage of termites as well as wood moisture under dry-substrate conditions. Our studies suggest that burying polyacrylamide/attapulgite composite within dry soil may enhance foraging activities of termites, but filling the bait stations with polyacrylamide/attapulgite composite may not effectively attract termites.

Soft Hydrogel Zwitterionic Coatings Minimize Fibroblast and Macrophage Adhesion on Polyimide Substrates

Minimizing the foreign body reaction to polyimide-based implanted devices plays a pivotal role in several biomedical applications. In this work, we propose materials exhibiting nonbiofouling properties and a Young's modulus reflecting that of soft human tissues. We describe the synthesis, characterization, and in vitro validation of poly(carboxybetaine) hydrogel coatings covalently attached to polyimide substrates via a photolabile 4-azidophenyl group, incorporated in poly(carboxybetaine) chains at two concentrations of 1.6 and 3.1 mol %. The presence of coatings was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy. White light interferometry was used to evaluate the coating continuity and thickness (between 3 and 6 μm under dry conditions). Confocal laser scanning microscopy allowed us to quantify the thickness of the swollen hydrogel coatings that ranged between 13 and 32 μm. The different hydrogel formulations resulted in stiffness values ranging from 2 to 19 kPa and led to different fibroblast and macrophage responses in vitro. Both cell types showed a minimum adhesion on the softest hydrogel type. In addition, both the overall macrophage activation and cytotoxicity were observed to be negligible for all of the tested material formulations. These results are a promising starting point toward future advanced implantable systems. In particular, such technology paves the way for novel neural interfaces able to minimize the fibrotic reaction, once implanted in vivo, and to maximize their long-term stability and functionality.

Poly(N-isopropylacrylamide)/polydopamine/clay nanocomposite hydrogels with stretchability, conductivity, and dual light- and thermo- responsive bending and adhesive properties

Conducting hydrogels have attracted attention as a special functional class of smart soft materials and have found applications in various advanced fields. However, acquiring all the characteristics such as conductivity, adequate adhesiveness, self-healing ability, stretchability, biocompatibility, and stimulating deformation responsiveness still remains a challenge. Inspired by the mechanism of bioadhesion in marine mussels, a multifunctional nanocomposite hydrogel with excellent adhesiveness to a broad range of substrates including human skin was developed with the help of synergistic multiple coordination bonds between clay, poly(N-isopropylacrylamide) (PNIPAM), and polydopamine nanoparticles (PDA-NPs). The prepared hydrogel showed controllable near-infrared (NIR) responsive deformation after incorporation of PDA-NPs as highly effective photothermal agents in the thermo-sensitive PNIPAM network. Meanwhile, the fabricated nanocomposite hydrogels showed excellent stretchability and conductivity, which make them attractive material candidates for application in various fields, such as electronic skin, wearable devices, and so on.

Inhibiting Bacterial Adhesion by Mechanically Modulated Microgel Coatings

Bacterial infection is a severe problem especially when associated with biomedical applications. This study effectively demonstrates that poly- N-isopropylmethacrylamide based microgel coatings prevent bacterial adhesion. The coating preparation via a spraying approach proved to be simple and both cost and time efficient creating a homogeneous dense microgel monolayer. In particular, the influence of cross-linking density, microgel size, and coating thickness was investigated on the initial bacterial adhesion. Adhesion of Staphylococcus aureus ATCC 12600 was imaged using a parallel plate flow chamber setup, which gave insights in the number of the total bacteria adhering per unit area onto the surface and the initial bacterial deposition rates. All microgel coatings successfully yielded more than 98% reduction in bacterial adhesion. Bacterial adhesion depends both on the cross-linking density/stiffness of the microgels and on the thickness of the microgel coating. Bacterial adhesion decreased when a lower cross-linking density was used at equal coating thickness and at equal cross-linking density with a thicker microgel coating. The highest reduction in the number of bacterial adhesion was achieved with the microgel that produced the thickest coating ( h = 602 nm) and had the lowest cross-linking density. The results provided in this paper indicate that microgel coatings serve as an interesting and easy applicable approach and that it can be fine-tuned by manipulating the microgel layer thickness and stiffness.

Biodegradable Thermomagnetically Responsive Soft Untethered Grippers

Soft-robotic devices such as polymeric microgrippers offer the possibility for pick and place of fragile biological cargo in hard-to-reach conduits with potential applications in drug delivery, minimally invasive surgery, and biomedical engineering. Previously, millimeter-sized self-folding thermomagnetically responsive soft grippers have been designed, fabricated, and utilized for pick-and-place applications but there is a concern that such devices could get lost or left behind after their utilization in practical clinical applications in the human body. Consequently, strategies need to be developed to ensure that these soft-robotic devices are biodegradable so that they would disintegrate if left behind in the body. In this paper, we describe the photopatterning of bilayer gels composed of a thermally responsive high-swelling poly(oligoethylene glycol methyl ether methacrylate ( M_n = 500)-bis(2-methacryloyl)oxyethyl disulfide), P(OEGMA-DSDMA), and a low-swelling poly(acrylamide- N, N'-bis(acyloyl)cystamine) hydrogel, in the shape of untethered grippers. These grippers can change shape in response to thermal cues and open and close due to the temperature-induced swelling of the P(OEGMA-DSDMA) layer. We demonstrate that the grippers can be doped with magnetic nanoparticles so that they can be moved using magnetic fields or loaded with chemicals for potential applications as drug-eluting theragrippers. Importantly, they are also biodegradable at physiological body temperature (∼37 °C) on the basis of cleavage of disulfide bonds by reduction. This approach that combines thermoresponsive shape change, magnetic guidance, and biodegradability represents a significant advance to the safe implementation of untethered shape-changing biomedical devices and soft robots for medical and surgical applications.

Zwitterionic Skins with a Wide Scope of Customizable Functionalities

With growing interest in the fields of wearable devices, it is crucial yet rather challenging to develop skinlike soft conductive materials with customizable functionalities and human tissue-compatible mechanical properties. Previously reported electronic skins struggle to meet the demands for transparence, mechanical adaptability, and stable conductivity during deformation. The recent rise of ionic skins with inorganic salts or ionic liquids doping provides the intrinsic stretchability, however, dilemmas remain for their limited functionalities such as a monotonous appearance and a narrow scope of mechanical and sensory properties. Herein, we design a type of zwitterionic hydrogels from the perspective of molecular interactions, which successfully combines ultrastretchability (>10000% strain), high strength (∼300 kPa), self-healability (at room temperature within 12 h), 3D printability, distinct stimuli-responsibility, biocompatibility, and antibacterial activity. The wide spectrum of such excellent properties has been rarely reported before and along with the ability to fabricate bioinspired intelligent skins recreating multiple sensations and mechanical properties of human skin, covering a broad range of sensitivity, and displaying tunable visual effect. We believe this work will inspire the programming of stimuli-responsive skinlike materials and contribute to the smart devices for information transformation between natural and artificial interfaces.