Chitosan Substrates Research Articles

The effect of surface roughness and chitosan deposition volume on microbial growth in biofilm involving titanium surfaces for orthopaedic applications

Orthopaedic hardware infections are a significant health and economic burden and have been reported to be the cause of many revision surgeries in total hip and knee arthroplasties. Many of these infections are caused by microbial growth in biofilm on the surface of the implanted device. Chitosan surface modifications of fracture fixation implants have shown to reduce infection rates and improve clinical results in orthopaedic procedures. Additional work is needed to determine the role of the chitosan deposition volume and substrate surface roughness on biofilm growth. In this study, titanium alloy discs were prepared to have a range of six surface roughness magnitudes, as well as four different concentrations of chitosan coatings. Analysis of in vitro tests with Staphylococcus aureus (S. aureus) showed that the bacterial concentration in biofilm was significantly affected by surface roughness and chitosan concentration. Titanium surfaces with low to intermediate average roughness values (between 0.1 and 1.5 µm) and higher concentrations of chitosan best inhibited biofilm adhesion. Additional work should explore the mechanisms of chitosan's antibacterial activity.

Crab-Eating Monkey Acidic Chitinase (CHIA) Efficiently Degrades Chitin and Chitosan under Acidic and High-Temperature Conditions.

Chitooligosaccharides, the degradation products of chitin and chitosan, possess anti-bacterial, anti-tumor, and anti-inflammatory activities. The enzymatic production of chitooligosaccharides may increase the interest in their potential biomedical or agricultural usability in terms of the safety and simplicity of the manufacturing process. Crab-eating monkey acidic chitinase (CHIA) is an enzyme with robust activity in various environments. Here, we report the efficient degradation of chitin and chitosan by monkey CHIA under acidic and high-temperature conditions. Monkey CHIA hydrolyzed α-chitin at 50 °C, producing N-acetyl-d-glucosamine (GlcNAc) dimers more efficiently than at 37 °C. Moreover, the degradation rate increased with a longer incubation time (up to 72 h) without the inactivation of the enzyme. Five substrates (α-chitin, colloidal chitin, P-chitin, block-type, and random-type chitosan substrates) were exposed to monkey CHIS at pH 2.0 or pH 5.0 at 50 °C. P-chitin and random-type chitosan appeared to be the best sources of GlcNAc dimers and broad-scale chitooligosaccharides, respectively. In addition, the pattern of the products from the block-type chitosan was different between pH conditions (pH 2.0 and pH 5.0). Thus, monkey CHIA can degrade chitin and chitosan efficiently without inactivation under high-temperature or low pH conditions. Our results show that certain chitooligosaccharides are enriched by using different substrates under different conditions. Therefore, the reaction conditions can be adjusted to obtain desired oligomers. Crab-eating monkey CHIA can potentially become an efficient tool in producing chitooligosaccharide sets for agricultural and biomedical purposes.

Surface adsorption of Pb 2+ ions from aqueous solutions using chitosan grafted with a mixture of IA-MAm / bentonite

ABSTRACT Water pollution with heavy metal ions is unsafe for drinking due to the toxicity of these ions. For this reason, the methods of removing these ions are of particular importance.In this study, a new medium molecular weight chitosan substrate adsorbent was grafted with a mixture of Itaconic acid (IA) – Methacrylamide (MAm) and bentonite. The characterisation was performed by XRD, FTIR, TGA and SEM methods. Its efficiency in adsorption of pb2+ ions was investigated by batch technique. The parameters affecting the adsorption were optimised. The best conditions for the adsorption of lead ions (time = 60 minutes, pH = 4.0, adsorbent = 0.02 g, adsorbate concentration = 400 mg/L and qmax = 520 mg/g) were recorded. Adsorption data were also fitted by Temkin-Piozhov and Langmuir isotherms and a Pseudo-second-order kinetic model, as well. Thermodynamic parameters showed that the adsorption process is endothermic and spontaneous and is associated with increased entropy. The adsorbent efficiency in the removal of lead ions in industrial effluents was good.

Integrated Portable Shrimp-Freshness Prediction Platform Based on Ice-Templated Metal–Organic Framework Colorimetric Combinatorics and Deep Convolutional Neural Networks

Real-time monitoring of food freshness is critical to reducing food waste and pursuing sustainable development. Cross-reactive artificial scent screening systems provide a promising solution for food freshness monitoring, but their commercialization is hindered by the low sensitivity or pattern-recognition inaccuracy. Leveraging the cutting-edge artificial intelligence and high-porosity nanomaterial, a cost-effective and versatile method was developed by incorporating metal–organic frameworks into smart food packaging via a colorimetric combinatorics sensor array. The whole UiO-66 family was screened by density functional theory calculations, and UiO-66-Br (due to the highest binding energy) was selected to construct sensor arrays on an ice-templated chitosan substrate (i.e., ice-templated dye@UiO-66-Br/Chitosan). The physicochemical properties and morphologies of the fabricated sensor arrays were systematically characterized. The limit of detection of 37.17, 25.90, and 40.65 ppm for ammonia, methylamine, and trimethylamine, respectively, was achieved by the prepared composite film. Deep convolutional neural networks (DCNN), a deep learning algorithm family, were further applied to monitor shrimp freshness by recognizing the scent fingerprint. Four state-of-the-art DCNN models were trained using 31,584 labeled images and 13,537 images for testing. The highest accuracy achieved was up to 99.94% by the Wide-Slice Residual Network 50 (WISeR50). Our newly developed platform is integrated, sensitive, and non-destructive, enabling consumers to monitor shrimp freshness in real-time conveniently.

Expression and Characterization of a Novel Cold-Adapted Chitosanase from Marine Renibacterium sp. Suitable for Chitooligosaccharides Preparation.

(1) Background: Chitooligosaccharides (COS) have numerous applications due to their excellent properties. Chitosan hydrolysis using chitosanases has been proposed as an advisable method for COS preparation. Although many chitosanases from various sources have been identified, the cold-adapted ones with high stability are still rather rare but required. (2) Methods: A novel chitosanase named CsnY from marine bacterium Renibacterium sp. Y82 was expressed in Escherichia coli, following sequence analysis. Then, the characterizations of recombinant CsnY purified through Ni–NTA affinity chromatography were conducted, including effects of pH and temperature, effects of metal ions and chemicals, and final product analysis. (3) Results: The GH46 family chitosanase CsnY possessed promising thermostability at broad temperature range (0–50 °C), and with optimal activity at 40 °C and pH 6.0, especially showing relatively high activity (over 80% of its maximum activity) at low temperatures (20–30 °C), which demonstrated the cold-adapted property. Common metal ions or chemicals had no obvious effect on CsnY except Mn2+ and Co2+. Finally, CsnY was determined to be an endo-type chitosanase generating chitodisaccharides and -trisaccharides as main products, whose total concentration reached 56.74 mM within 2 h against 2% (w/v) initial chitosan substrate. (4) Conclusions: The results suggest the cold-adapted CsnY with favorable stability has desirable potential for the industrial production of COS.

Integrated All-Fiber Electronic Skin toward Self-Powered Sensing Sports Systems.

The development of wearable electronic skins (E-skins) requires devices with high flexibility, breathability, and antibacterial activity, as in sports sensing technology. Here, we report a flexible, breathable, and antibacterial triboelectric nanogenerator (TENG)-based E-skin for self-powered sensing in volleyball reception statistics and analytics, which is fabricated by sandwiching a silver nanowire (Ag NW) electrode between a thermoplastic polyurethane (TPU) sensing layer and a poly(vinyl alcohol)/chitosan (PVA/CS) substrate. Benefiting from an outstanding breathability of 10.32 kg m-2 day-1 and biocidal properties of CS and Ag NW, the E-skin offers excellent thermal-moisture comfort and a remarkable antibacterial effect on Escherichia coli and Staphylococcus aureus. A pressure sensitivity of 0.3086 V kPa-1 is demonstrated in the sensing range of 6.65-19.21 kPa. Besides, a volleyball reception statistical and analytical system is further developed based on a 2 × 3 E-skin array. According to this work, the integration of wearable electronic devices with self-powered sensors may expand practical applications in sports.

Flexible Dual-Gate MoS₂ Neuromorphic Transistors on Freestanding Proton-Conducting Chitosan Membranes

Flexible neuromorphic devices are highly desirable for emerging perception and sensing systems. Here, multiterminal neuromorphic devices based on freestanding dual-gate MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> transistors on freestanding proton-conducting chitosan membranes are proposed. The chitosan membranes are simultaneously used as the dielectrics and substrates. By replicating the surface of silicon substrate, the roughness of chitosan substrate is successfully reduced from 11 to 1.7 nm. Besides, the membranes show a large specific in-plane electric-double-layer capacitance of 1.3 μF/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 1.0 Hz when the interelectrode space is 100 μm. The dual-gate MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> transistors exhibit high mechanical stability and electrical performance on flexible chitosan membranes. Some important synaptic functions, such as paired-pulse facilitation, and tunable high pass filter, are successfully emulated. Furthermore, spatiotemporal dynamic correlation is also experimentally demonstrated. Our results will greatly enrich the intension of 2-D flexible electronics and neuromorphic perception and sensing systems.

Modeling and Experimental Validation of Algorithms for Maximum Quantity of Protein to be Immobilized on Solid Supports by Electrostatic Adsorption in the Strategy of Rational Design of Immobilized Derivatives.

Protein immobilization by electrostatic adsorption to a support could represent a good option. On the other hand, lysozyme (EC 3.2.1.17) is a little and basic protein. The objective of this work was to test the functionality of the strategy of Rational Design of Immobilized Derivatives for the immobilization by electrostatic adsorption of egg white lysozyme on SP-Sepharose FastFlow support. The RDID1.0 software was used to predict the superficial lysozyme clusters, the electrostatic configuration probability for each cluster, and the theoretical and estimated maximum quantity of protein to be immobilized. In addition, immobilization was performed and the experimental parameter practical maximum quantity of protein to be immobilized and the enzymatic activity of the immobilized derivative were assessed. The estimated maximum quantity of protein to be immobilized (9.49 protein mg/support g) was close to the experimental practical maximum quantity of protein to be immobilized (14.73 ± 0.09 protein mg/support g). The enzymatic activity assay with the chitosan substrate showed the catalytic functionality of the lysozyme-SP-Sepharose immobilized derivative (35.85 ± 3.07 U/support g), which preserved 78% functional activity. The used algorithm to calculate the estimated maximum quantity of protein to be immobilized works for other proteins, porous solid supports and immobilization methods, and this parameter has a high predictive value, useful for obtaining optimum immobilized derivatives. The applied methodology is valid to predict the most probable protein-support configurations and their catalytic competences, which concur with the experimental results. The produced biocatalyst had a high retention of functional activity. This indicates its functionality in enzymatic bioconversion processes.

Effect of selected substrates and chitosan on growth performance of orchid tissue culture seedling under net house

Orchids are considered as the most beautiful and significant cut blossom and pruned plants throughout the world. Therefore tissue culture technique was used as one of the alternative to mass propagate the orchids to fulfil the demand. This study was conducted to find out the effect of chitosan and different substrates on growth performance of Dendrobium Shavin White orchid seedling from tissue culture environment to net house. The tissue cultured plants went through prehardening stage to reduce mortality after the switch to ex vitro conditions. Five (5) treatments consist of combination substrates were tested which were T1: rice husk + chitosan, T2: peat moss + chitosan, T3: EFB + chitosan, T4: rice husk + peat moss + chitosan and T5: rice husk + peat moss + EFB + chitosan whereas charcoal as a control (T0). The result showed that the highest plant height and leaf length which did not significantly different were T3 (6.20cm plant height, 4.83cm leaf length), and T5 (6.55cm plant height, 4.51cm leaf length). Meanwhile, T3 was an effective for number of leaf production with 4.14 leaf count. Hence, this data will be used to acclimatize tissue cultured of Dendrobium Shavin White orchid for commercial used.

Conductive PEDOT:PSS on surface-functionalized chitosan biopolymers for stretchable skin-like electronics

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a promising alternative transparent electrode to replace conventional indium tix oxide (ITO) for flexible and stretchable electronics. For their applications in optoelectronic devices, realizing both high conductivity and transmittance for the films is of great necessity as a suitable high performance transparent electrode. Here, we demonstrate simultaneously enhanced electrical and optical properties of PEDOT:PSS films prepared on chitosan bio-substrates by using an organic surface modifier, 11-aminoundecanoic acid (11-AA). The sheet resistance of PEDOT:PSS films decreases from 1120.8 to 292.8 Ω/sq with an increase in a transmittance from 75.9 to 80.4% by 11-AA treatment on the chitosan films. The functional groups of 11-AA effectively enhance the adhesion property at the interface between the chitosan substrate and PEDOT:PSS by forming strong interfacial bondings and decrease insulating PSS from PEDOT:PSS films. The wearable heater devices and on-skin sensors based on the 11-AA-treated PEDOT:PSS on the chitosan bio-substrates are successfully fabricated, showing the excellent thermal and sensing performances. The 11-AA surface-modification approach for highly conductive PEDOT:PSS on chitosan bio-substrates presents a great potential for applications toward transparent, flexible and stretchable electronics.

Production of Structurally Defined Chito-Oligosaccharides with a Single N-Acetylation at Their Reducing End Using a Newly Discovered Chitinase from Paenibacillus pabuli.

Partially acetylated chito-oligosaccharides (paCOSs) are bioactive compounds with potential medical applications. Their biological activities are largely dependent on their structural properties, in particular their degree of polymerization (DP) and the position of the acetyl groups along the glycan chain. The production of structurally defined paCOSs in a purified form is highly desirable to better understand the structure/bioactivity relationship of these oligosaccharides. Here, we describe a newly discovered chitinase from Paenibacillus pabuli (PpChi) and demonstrate by mass spectrometry that it essentially produces paCOSs with a DP of three and four that carry a single N-acetylation at their reducing end. We propose that this specific composition of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) residues, as in GlcN(n)GlcNAc1, is due to a subsite specificity toward GlcN residues at the −2, −3, and −4 positions of the partially acetylated chitosan substrates. In addition, the enzyme is stable, as evidenced by its long shelf life, and active over a large temperature range, which is of high interest for potential use in industrial processes. It exhibits a kcat of 67.2 s–1 on partially acetylated chitosan substrates. When PpChi was used in combination with a recently discovered fungal auxilary activity (AA11) oxidase, a sixfold increase in the release of oligosaccharides from the lobster shell was measured. PpChi represents an attractive biocatalyst for the green production of highly valuable paCOSs with a well-defined structure and the expansion of the relatively small library of chito-oligosaccharides currently available.

Chitosan based biomaterials for cartilage tissue engineering: Chondrocyte adhesion and proliferation

Multidisciplinary approaches encompassing developmental biology, tissue mechanics, cell differentiation, and nano-fabrication technology hold great promise for the effective biological repair of cartilage. In this aim, the present work proposed the use of chitosan (CS)-based fiber mats obtained by electrospinning as a scaffold for chondrocyte development in order to take advantage of the biocompatibility with native tissues. Cell viability, adhesion and proliferation were studied and compared as a function of the substrate morphology and chitosan neutralization. Fibers with two different diameters are investigated and it is shown that the cells develop better on fibers when compared with films. Early observations of cell adhesion revealed that a maximum of seeded cells is attached to the fiber substrate during the first 8 h after seeding. High ratio of living chondrocytes (>80%) was found on all types of chitosan supports examined. However, cell viability is shown to be favored on engineered CS fiber mats especially for lower diameter fibers. In that case, chondrocytes attached to thin neutralized chitosan fibers were observed to reach a proliferation ratio of 15:1 between day 14 and day 1, respectively. The influence of chitosan neutralization step on cell proliferation is also studied. Overall, CS substrates may be considered as a possible implantable scaffold for chondrocyte development, providing an adapted microenvironment for native cells to adhere, colonize, and repair the damaged tissue.

Compounded topographical and physicochemical cueing by micro-engineered chitosan substrates on rat dorsal root ganglion neurons and human mesenchymal stem cells.

Given the intertwined physicochemical effects exerted in vivo by both natural and synthetic (e.g., biomaterial) interfaces on adhering cells, the evaluation of structure-function relationships governing cellular response to micro-engineered surfaces for applications in neuronal tissue engineering requires the use of in vitro testing platforms which consist of a clinically translatable material with tunable physiochemical properties. In this work, we micro-engineered chitosan substrates with arrays of parallel channels with variable width (20 and 60 μm). A citric acid (CA)-based crosslinking approach was used to provide an additional level of synergistic cueing on adhering cells by regulating the chitosan substrate's stiffness. Morphological and physicochemical characterization was conducted to unveil the structure-function relationships which govern the activity of rat dorsal root ganglion neurons (DRGs) and human mesenchymal stem cells (hMSCs), ultimately singling out the key role of microtopography, roughness and substrate's stiffness. While substrate's stiffness predominantly affected hMSC spreading, the modulation of the channels' design affected the neuronal architecture's complexity and guided the morphological transition of hMSCs. Finally, the combined analysis of tubulin expression and cell morphology allowed us to cast new light on the predominant role of the microtopography over substrate's stiffness in the process of hMSCs neurogenic differentiation.

Single‐Material OECT‐Based Flexible Complementary Circuits Featuring Polyaniline in Both Conducting Channels

AbstractThe organic electrochemical transistor (OECT) with a conjugated polymer as the active material is the elementary unit of organic bioelectronic devices. Improved functionalities, such as low power consumption, can be achieved by building complementary circuits featuring two or more OECTs. Complementary circuits commonly combine both p‐ and n‐type transistors to reduce power draw. While p‐type OECTs are readily available, n‐type OECTs are less common mainly due to poor stability of the n‐type active channel material in aqueous electrolyte. Here, a complementary circuit is made using a pair of OECTs having polyaniline (PANI) as the channel material in both transistors. PANI, with a finite electrochemical window accessible at voltages lower than 1 V, exhibits a peak in current versus gate voltage when used as an active channel in an OECT. The current peak has two slopes, one n‐like and one p‐like, which correspond to different electrochemical regimes of the same underlying conjugated polymer. The electrochemistry enables the design of a complementary circuit using only PANI as the channel material. The PANI‐based circuit is shown to have excellent performance with gain of ≈7 and is transferred on a flexible biocompatible chitosan substrate with demonstrated operation in aqueous electrolyte.

Chitosan-Graphene Oxide-Based Ultra-Thin and Flexible Sensor for Diabetic Wound Monitoring

This paper presents a Chitosan-Graphene Oxide (CS-GO)-based array of ultra-thin biosensors with gold (Au)-based microgap (60 μm) electrode. The cross-linked GO is shown to improve the stability of chitosan substrate in aqueous medium and compatibility with microfabrication steps. The sensor patch has been evaluated for label-free monitoring by immobilizing the CS-GO surface with human dermal fibroblast (HDF) cells. The cyclic voltammetry (CV) of HDF cell immobilized CS-GO surface show quasi-reversible nature with a characteristic cathodic peak at +300 mV and anodic peak at -300 mV. Both peaks are stable and repeatable up to 50-scan cycle without any potential shift. The device shows a steady-state peak enhancement (1.923-11.195nA) during the DHF cell growth period (0-96h). The redox peak enhancement correlates with the cell proliferation rates over time, indicating that it could be employed for investigation of the cyto-physiological state against any endo and exogenous stimulation. In addition, the developed sensor-patch was used to detect a wide range of glucose from 1 μM to 20mM in vitro with a sensitivity of 0.17 μA/mM. Considering these, the presented sensor-patch has a great potential for the detection of glucose level, cell-health proliferation rate at the wound site, and diabetic wound monitoring applications.

Determination and Quantification of the Distribution of CN-NL Nanoparticles Encapsulating Glycyrrhetic Acid on Novel Textile Surfaces with Hyperspectral Imaging.

Chitin Lignin nanoparticles (CN-NL), standalone and encapsulating glycyrrhetic acid (GA), were applied on novel substrates for textiles to obtain antibacterial, antioxidant properties. Their homogeneous application is an important parameter that can strongly influence the final performance of the investigated textiles for its cosmetic and medical use. In this paper, hyperspectral imaging techniques combined with chemometric tools were investigated to study the distribution and quantification of CN-NL/GA on chitosan and CN-NL on pullulan substrates. To do so, samples of chitosan and pullulan impregnated with CN-NL/GA and CN-NL were analysed through Short Wave Infrared (SWIR) and Visible-Near Infrared (VisNIR) hyperspectral cameras. Two different chemometric tools for qualitative and quantitative analysis have been applied, principal component analysis (PCA) and partial least square regression (PLSR) models. Promising results were obtained in the VisNIR range, which made it possible for us to visualize the CN-NL/GA compound on chitosan and CN-NL on pullulan substrates. Additionally, the PLSR model results had determination coefficient ( for calibration and cross-validation ( values of 0.983 and 0.857, respectively. Minimum values of root-mean-square error for calibration (RMSEC) and cross-validation (RMSECV) of CN-NL/GA were 0.333 and 0.993 g, respectively. The results demonstrate that hyperspectral imaging combined with chemometrics offers a powerful tool for studying the distribution on chitosan and pullulan substrates and to quantify the content of CN-NL/GA compounds on chitosan substrates.

PCL-Blended Chitosan Substrates for Patterning the Heterotypic Cell Distribution in an Epithelial and Mesenchymal Coculture System.

Cell-cell and cell-substrate interactions in coculture systems are very important to the context of biomaterial scaffolds for tissue engineering applications. Understanding the cellular interactions and distribution of epithelial-mesenchymal microtissues on the controllable biomaterial surfaces is useful to study the organoid applications. The aim of the present study is to investigate the effects of chitosan/poly(ε-caprolactone) (PCL)-blended biomaterials on the distribution and spheroid formation of HaCaT and Hs68 cells in a coculture system. In this study, we demonstrated that the cocultured cells gradually changed their pattern from core/shell spheroid to monolayered morphology as the PCL content increased in the blended substrates. This indicates that the chitosan/PCL-blended substrates are able to regulate cell-substrate and cell-cell interactions to modify the distribution of HaCaT and Hs68 cells similar to various mesenchymal-epithelial organizations in biological tissues. Moreover, we also developed a two-dimension lattice model to elaborate the dependence of cell spheroid development on complex cell-cell interactions. This information may be helpful to develop appropriate biomaterials with appropriate properties to the applications of engineered epithelial-mesenchymal organoids.

Label-free platform on pH-responsive chitosan: Adhesive heterogeneity for cancer stem-like cell isolation from A549 cells via integrin β4

Great efforts have been paid to develop methodologies for cancer stem-like cell (CSLC) isolation in anti-cancer research. The major obstacle lies in the lack of generic biomarkers for different cancer types and the requirement of complicated immuno-labeling procedures. The purpose of this study is to establish a label-free platform for CSLC isolation using pH-responsive chitosan. Based on the adhesive heterogeneity, 15.7 ± 1.9 % of human non-small cell lung cancer (NSCLC) cell line A549 detached from the chitosan substrate following medium pH elevation from 6.99 to 7.65 within 1 h. As a result, this subpopulation of cells with low adhesiveness exhibited superior CSLC hallmarks, including self-renewal, invasive and metastatic potential, therapeutic-resistance, colony formation in vitro, as well as nude mice xenograft in vivo for tumorigenesis, in comparison with their high-adhesive counterpart. Furthermore, integrin β4 is decisive in controlling CSLC detachment of NSCLC. Conclusively, this pH-dependent isolation provides new insights into biomaterial-based CSLC isolation.

Thermoplastic biomass transparent films directly fabricated by chitosan nanospheres

Traditional fabrication methods for chitosan products limited in melt forming temperature higher than degradation temperature are hard to be directly applied to the manufacture of green transparent electronic substrates. Here, we proposed an innovative principle of all-green manufacture that surface molecular chains of chitosan nanospheres were melted at 120 °C and entangled under 8 MPa according to high molecules activity of Nano-effect on chitosan nanospheres surface, result in applicable mechanical performances (Hardness, 0.27 GPa; Modulus, 3.83 GPa). The optimum optical performance of chitosan substrate was 58% at visible light (400 nm ~ 800 nm). Additionally, chitosan nanospheres had been successfully fabricated as substrates of interdigital electrode sensors. Therefore, our innovative strategy provides a new processing concept of fundamental scientific principle, and directly promote the industrialization of chitosan in biosensors, thin film transistors, and all solid state supercapacitors, etc.

Increased Cell Detachment Ratio of Mesenchymal-Type Lung Cancer Cells on pH-Responsive Chitosan through the β3 Integrin.

Chitosan is sensitive to environmental pH values due to its electric property. This study investigates whether the pH-responsive chitosan assay can provide a simple method to evaluate the aggressive behavior of cancer cells with cell detachment ratio. The epithelial–mesenchymal transition (EMT) is induced with transforming growth factor-β1 (TGF-β1) in the human non-small cell lung cancer cell line (A549). EMT-induced cells and untreated cells are cultured on chitosan substrates at pH 6.99 for 24 h, followed by pH 7.65 for 1 h. The cell detachment ratio (CDR) on pH-responsive chitosan rises with an increasing of the TGF-β1 concentration. The protein array reveals that the expression levels of the α2, α3, α5, β2, and β3 integrins are higher in EMT-induced A549 cells than in untreated cells. A further inhibition assay shows that adding β3 integrin blocking antibodies significantly decreases the CDR of EMT-induced cells from 32.7 ± 5.7% to 17.8 ± 2.1%. The CDR of mesenchymal-type lung cancer cells increases on pH-responsive chitosan through the β3 integrin. Notably, the CDR can be theoretically predicted according to the individual CDR on the pH-responsive chitosan surface, irrespective of heterogeneous cell mixture. The pH-responsive chitosan assay serves as a simple in vitro model to investigate the aggressive behavior of lung cancer including the heterogeneous cell population.