Paper-based devices have been broadly used for the point-of-care detection of dengue viral nucleic acids due to their simplicity, cost-effectiveness, and readily observable colorimetric readout. However, their moderate sensitivity and functionality have limited their applications. Despite the above-mentioned advantages, paper substrates are lacking in their ability to control fluid flow, in contrast to the flow control enabled by polymer substrates (e.g., agarose) with readily tunable pore size and porosity. Herein, taking the benefits from both materials, the authors propose a strategy to create a hybrid substrate by incorporating agarose into the test strip to achieve flow control for optimal biomolecule interactions. As compared to the unmodified test strip, this strategy allows sensitive detection of targets with an approximately tenfold signal improvement. Additionally, the authors showcase the potential of functionality improvement by creating multiple test zones for semi-quantification of targets, suggesting that the number of visible test zones is directly proportional to the target concentration. The authors further demonstrate the potential of their proposed strategy for clinical assessment by applying it to their prototype sample-to-result test strip to sensitively and semi-quantitatively detect dengue viral RNA from the clinical blood samples. This proposed strategy holds significant promise for detecting various targets for diverse future applications.
Bacterial cellulose (BC)/acrylic acid (AA) hydrogel has successfully been investigated as a wound dressing for partial-thickness burn wound. It is also a promising biomaterial cell carrier because it bears some resemblance to the natural soft tissue. This study assessed its ability to deliver human epidermal keratinocytes (EK) and dermal fibroblasts (DF) for the treatment of full-thickness skin lesions. In vitro studies demonstrated that BC/AA hydrogel had excellent cell attachment, maintained cell viability with limited migration, and allowed cell transfer. In vivo wound closure, histological, immunohistochemistry, and transmission electron microscopy evaluation revealed that hydrogel alone (HA) and hydrogel with cells (HC) accelerated wound healing compared to the untreated controls. Gross appearance and Masson's trichrome staining indicated that HC was better than HA. This study suggests the potential application of BC/AA hydrogel with dual functions, as a cell carrier and wound dressing, to promote full-thickness wound healing.
Biomaterials provide novel platforms to deliver stem cell and growth factor therapies for central nervous system (CNS) repair. The majority of these approaches have focused on the promotion of neural progenitor cells and neurogenesis. However, it is now increasingly recognized that glial responses are critical for recovery in the entire neurovascular unit. In this study, we investigated the cellular effects of epidermal growth factor (EGF) containing hydrogels on primary astrocyte cultures. Both EGF alone and EGF-hydrogel equally promoted astrocyte proliferation, but EGF-hydrogels further enhanced astrocyte activation, as evidenced by a significantly elevated Glial fibrillary acidic protein (GFAP) gene expression. Thereafter, conditioned media from astrocytes activated by EGF-hydrogel protected neurons against injury and promoted synaptic plasticity after oxygen-glucose deprivation. Taken together, these findings suggest that EGF-hydrogels can shift astrocytes into neuro-supportive phenotypes. Consistent with this idea, quantitative-polymerase chain reaction (qPCR) demonstrated that EGF-hydrogels shifted astrocytes in part by downregulating potentially negative A1-like genes (Fbln5 and Rt1-S3) and upregulating potentially beneficial A2-like genes (Clcf1, Tgm1, and Ptgs2). Further studies are warranted to explore the idea of using biomaterials to modify astrocyte behavior and thus indirectly augment neuroprotection and neuroplasticity in the context of stem cell and growth factor therapies for the CNS. Stem Cells Translational Medicine 2019;8:1242&1248.
Inflammation is a key challenge in the treatment of chronic diseases. Spurred by topical advancement in polymer chemistry and drug delivery, hydrogels that release a drug in temporal, spatial and dosage controlled fashion have been trendy. This research focused on the fabrication of hydrogels with controlled drug release properties to control inflammation. Chitosan and polyvinyl pyrrolidone were used as base polymers and crosslinked with epichlorohydrin to form hydrogel films by solution casting technique. Prepared hydrogels were analyzed by swelling analysis in deionized water, buffer and electrolyte solutions and gel fraction. Functional groups confirmation and development of new covalent and hydrogen bonds, thermal stability (28.49%) and crystallinity were evaluated by FTIR, TGA and WAXRD, respectively. Rheological properties including gel strength and yield stress, elasticity (2309 MPa), porosity (75%) and hydrophilicity (73°) of prepared hydrogels were also evaluated. In vitro studies confirmed that prepared hydrogels have good biodegradability, excellent antimicrobial property and admirable cytotoxicity. Drug release profile (87.56% in 130 min) along with the drug encapsulation efficiency (84%) of prepared hydrogels was also studied. These results paved the path towards the development of hydrogels that can release the drugs with desired temporal patterns.
Biofilms comprise bacteria attached to wound surfaces and are major contributors to non-healing wounds. It was found that the increased resistance of biofilms to antibiotics allows wound infections to persist chronically in spite of antibiotic therapy. In this study, the reduced form of graphene oxide (rGO) was explored as plausible antibiofilm agents. The rGO was synthesized via reducing the functional groups of GO. Then, rGO were characterized using zetasizer, X-ray photoelectron spectroscopy, UV-Vis spectroscopy and FESEM. The rGO were then formulated into sodium carboxymethyl cellulose (NaCMC) hydrogels to form rGO hydrogel and tested for antibiofilm activities in vitro using XTT test, and in vivo biofilm formation assay using nematodes C. elegans. Reduced GO hydrogel was successfully formed by reducing the functional groups of GO, and a reduction of up to 95% of functional groups was confirmed with X-ray photoelectron spectroscopy analysis. XTT tests confirmed that rGO hydrogels reduced biofilm formation by S. aureus (81-84%) and P. aeruginosa (50-62%). Fluorescence intensity also confirmed that rGO hydrogel can inhibit biofilm bacteria in C. elegans experiments. This study implied that rGO hydrogel is an effective antibiofilm agent for infected wounds.
Lipase from Candida rugosa was immobilized by entrapment on poly(N-vinyl- 2-pyrrolidone-co-2-hydroxyethyl methacrylate) (poly[VP-co-HEMA]) hydrogel, and divinylbenzene was the crosslinking agent. The immobilized enzymes were used in the esterification reaction of oleic acid and butanol in hexane. The activities of the immobilized enzymes and the leaching ability of the enzyme from the support with respect to the different compositions of the hydrogels were investigated. The thermal, solvent, and storage stability of the immobilized lipases was also determined. Increasing the percentage of composition of VP from 0 to 90, which corresponds to the increase in the hydrophilicity of the hydrogels, increased the activity of the immobilized enzyme. Lipase immobilized on VP(%):HEMA(%) 90:10 exhibited the highest activity. Lipase immobilized on VP(%):HEMA(%) 50:50 showed the highest thermal, solvent, storage, and operational stability compared to lipase immobilized on other compositions of hydrogels as well as the native lipase.
Natural polymer guar gum has one of the highest viscosities in water solution and hence, these are significantly used in pharmaceutical applications. Guar gum inter-connected micelles as a new carrier has been developed for poor water soluble rifampicin drug. The hydrogel inter-connected micelle core was formulated as a hydrophilic inner and hydrophobic outer core by using guar gum/chitosan/polycaprolactone and the carrier interaction with rifampicin was confirmed by FT-IR. The morphological observations were carried out through TEM, SEM and AFM analysis. The encapsulation efficiency and in-vitro drug release behavior of prepared hydrogel based micelle system was analyzed by UV-vis spectrometry. The anti-bacterial activity against K. pneumoniae and S. aureus was studied by observing their ruptured surface by SEM. The cytotoxicity study reveals that the pure polymeric system has no toxic effect whereas drug loaded ones showed superior activity against THP-1 cells. From the cell apoptosis analyses, the apoptosis was carried out in a time dependent manner. The cell uptake behavior was also observed in THP-1 cells which indicate that the hydrogel based micelle system is an excellent material for the mucoadhesive on intracellular alveolar macrophage treatment.
Introduction: Tissue-engineered oral mucosa (TEOM) is increasingly being used to model oral mucosal diseases and to assess drug toxicity. Current TEOM models are constructed using normal oral fibroblasts (NOF) contained within a hydrogel matrix with normal oral keratinocytes (NOK) cultured on top. NOK are not commercially available and suffer from donor-to-donor variability. Therefore, oral mucosal models based on immortalised keratinocytes may offer advantages over NOK-based models. The objective of this study was to construct and characterise the TEOM developed using TERT2-immortalised oral keratinocyte (FNB6) cells and validate its similarity to normal oral muco-sal tissue. Methods: TEOM were constructed by culturing FNB6 cells on top of a NOF-populated collagen type-1 hydrogel in tissue culture transwell inserts cultured at an air-to-liquid interface and collected at 14 day. TEOM were subjected to morphological (H&E and PAS), ultrastructural (TEM) and immunohistological (Ki-67, cytokeratin 14 and E-cadherin) analysis. Results: Histologically TEOM mimicked native oral mucosa displaying a stratified epithelium, fibroblast-containing connective tissue and basement membrane. Furthermore, TEM confirmed the presence of des-mosomes and hemi-desmosomes in the epithelium. IHC revealed expression of differentiation markers (cytokeratin 14), proliferation (Ki-67), cell adhesion (E-cadherin). Conclusion: FNB6 mucosal models able to mimic native oral mucosa structure. It has potential for drug delivery and toxicity evaluation, and replacing models based on NOK where access to primary cells is limited.
Pectin is an anionic, water-soluble polymer predominantly consisting of covalently 1,4-linked α-d-galacturonic acid units. This naturally occurring, renewable and biodegradable polymer is underutilized in polymer science due to its insolubility in organic solvents, which renders conventional polymerization methods impractical. To circumvent this problem, cerium-initiated radical polymerization was utilized to graft methoxy-poly(ethylene glycol) methacrylate (mPEGMA) onto pectin in water. The copolymers were characterized by ¹H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), and used in the formation of supramolecular hydrogels through the addition of α-cyclodextrin (α-CD) to induce crosslinking. These hydrogels possessed thixotropic properties; shear-thinning to liquid upon agitation but settling into gels at rest. In contrast to most of the other hydrogels produced through the use of poly(ethylene glycol) (PEG)-grafted polymers, the pectin-PEGMA/α-CD hydrogels were unaffected by temperature changes.
Over recent years, keratin has gained great popularity due to its exceptional biocompatible and biodegradable nature. It has shown promising results in various industries like poultry, textile, agriculture, cosmetics, and pharmaceutical. Keratin is a multipurpose biopolymer that has been used in the production of fibrous composites, and with necessary modifications, it can be developed into gels, films, nanoparticles, and microparticles. Its stability against enzymatic degradation and unique biocompatibility has found their way into biomedical applications and regenerative medicine. This review discusses the structure of keratin, its classification and its properties. It also covers various methods by which keratin is extracted like chemical hydrolysis, enzymatic and microbial treatment, dissolution in ionic liquids, microwave irradiation, steam explosion technique, and thermal hydrolysis or superheated process. Special emphasis is placed on its utilisation in the form of hydrogels, films, fibres, sponges, and scaffolds in various biotechnological and industrial sectors. The present review can be noteworthy for the researchers working on natural protein and related usage.
The accumulation of tear film proteins as well as microbes colonization onto worn contact lenses can be eliminated conventionally by mechanical rubbing during the cleaning process. Lens2® functions in rotation manner to loosen the deposits on the contact lens and has antimicrobial coating to keep lenses away from contamination. The objective of this study was to determine the efficiency of Lens2® to remove deposited protein and reduce microbial contamination compared to conventional method. Twenty-eight subjects each wore a pair of contact lens FDA Group 1 (Polymacon, SoftLens® 38, Bausch & Lomb) for one month and cleaned them using multipurpose solution (COMPLETE® MoisturePLUSTM, Advanced Medical Optics) separately using two different methods. The right lens was cleaned conventionally while the left lens were cleaned using the Lens2®. The control group of thirteen subjects each wore a pair of contact lens for the same period and cleaned both conventionally. These lenses and its cases were then analyzed for protein deposition using Bichinchoninic Acid Assay (BCA) Kit (Sigma, USA) in 96-well plate. Microbial contamination was determined by culturing the samples on nutrient agar for bacteria and fungi and non-nutrient agar for amoeba isolation. The mean of total protein on control lenses (17.014 ± 13.246 µg/mL) was not significantly different from those on the Lens2® (21.623 ± 19.127 µg/mL). There were also low growth numbers of amoeba in each group of samples. Interestingly, there were no growths of amoeba from all Lens2® samples collected. There was also low growth numbers of bacteria in each sample group whereby Lens2® had the lowest growth of bacteria. No growth of fungi was obtained from all samples. The automatic lens cleaner, Lens2® was found to be as efficient as the conventional cleaning method. However, the Lens2® has additional advantage because of its antimicrobial material and need shorter time in the cleaning process as well as easy and effective.
In this work, hydrogels were prepared from carboxymethyl cellulose (CMC) and 1-vinyl-2-pyrrolidone(VP) by Electron Beam irradiation in the presence of N,N'-methylenebisacrylamide (BIS) as a crosslinkingagent. The parameters studied include stirring time and percentage of crosslinking agent. Hydrogels werecharacterized using Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy(SEM). VP and BIS were found be effective as reinforcement materials to improve the properties ofCMC. Meanwhile, the optimum conditions were 5% BIS and 3 hours of stirring time. The gel fractionincreased when irradiation dose was increased. FTIR confirmed the crosslinking reaction between CMCand VP after the irradiation process by using BIS as the crosslinking agent. TGA thermograms showedchanges in the thermal properties of CMC-VP hydrogels in the presence of different amounts of BIS.
Microbial keratitis is the infection caused by pathogenic microorganisms that commonly occurs among the contact lens users. Various antimicrobial compounds were coated on contact lenses to kill keratitis causing microorganisms, however these compounds caused several adverse side effects. Hence, the aim of this study is to develop a silicone hydrogel contact lens coated with phomopsidione nanoparticle that inhibit keratitis causing clinical isolates. Phomopsidione nanoparticles were synthesized using polyvinyl alcohol as encapsulant. The nanoparticles showed an average size of 77.45 nm, with neutral surface charge. Two drug release patterns were observed in the drug release profile, which are the initial slow release phase with extended drug release (release rate 46.65 μg/h), and the burst release phase observed on Day 2 (release rate 2224.49 μg/h). This well-regulated drug delivery system enables the control of drug release to meet the therapeutic requirements. On agar diffusion assay, 3 out of 5 test microorganisms were inhibited by phomopsidione nanoparticle coated contact lenses, including two Gram negative bacteria. Besides, all test microorganisms showed at least 99% of growth reduction, with the treatment of the contact lens model. The drug loaded onto the nanoparticles is sufficient to prevent the bacterial growth. In conclusion, this study provides an effective alternative to combat keratitis-causing microorganisms among contact wearers.
Collagen and fibrin are widely used in tissue engineering due to their excellent biocompatibility and bioactivities that support in vivo tissue formation. These two hydrogels naturally present in different wound healing stages with different regulatory effects on cells, and both of them are mechanically weak in the reconstructed hydrogels. We conducted a comparative study by the growth of rat dermal fibroblasts or dermal fibroblasts and epidermal keratinocytes together in collagen and fibrin constructs respectively with and without the reinforcement of electrospun poly(lactic acid) nanofiber mesh. Cell proliferation, gel contraction and elastic modulus of the constructs were measured on the same gels at multiple time points during the 22 day culturing period using multiple non-destructive techniques. The results demonstrated considerably different cellular activities within the two types of constructs. Co-culturing keratinocytes with fibroblasts in the collagen constructs reduced the fibroblast proliferation, collagen contraction and mechanical strength at late culture point regardless of the presence of nanofibers. Co-culturing keratinocytes with fibroblasts in the fibrin constructs promoted fibroblast proliferation but exerted no influence on fibrin contraction and mechanical strength. The presence of nanofibers in the collagen and fibrin constructs played a favorable role on the fibroblast proliferation when keratinocytes were absent. Thus, this study exhibited new evidence of the strong cross-talk between keratinocytes and fibroblasts, which can be used to control fibroblast proliferation and construct contraction. This cross-talk activity is extracellular matrix-dependent in terms of the fibrous network morphology, density and strength.
The present study intended to develop efficient hydrogel spheres in treating simulated wastewater contaminated with p-chlorophenol. Herein, copper-modified nanocellulose was grafted onto alginate to produce eco-friendly hydrogel spheres to utilize as a viable biosorbent. Fabricated spheres were characterized through scanning electron microscopy, thermogravimetry, surface area measurement, point of zero charge and zeta potential analyses. The adsorption of p-chlorophenol was optimized by altering various experimental conditions. Pseudo second order kinetics and Langmuir adsorption isotherm best described the adsorption of p-chlorophenol onto copper-modified cellulose nanocrystal-based spheres. The maximum adsorption capacity was 66.67 mg g-1 with a reusability up to five regeneration cycles. The thermodynamic study directed that p-chlorophenol adsorption was exothermic, spontaneous, and reversible within the analyzed temperature range. Weber-Morris model revealed that intraparticle diffusion was not the singular rate-controlling step in the adsorption process. Hence, copper-modified nanocellulose spheres could be employed as a sustainable and effective biosorbent for p-chlorophenol adsorption from wastewater.
The formidable barrier properties of the uppermost layer of the skin, the stratum corneum, impose significant limitations for successful systemic delivery of broad range of therapeutic molecules particularly macromolecules and genetic material. Microneedle (MN) has been proposed as a strategy to breach the stratum corneum barrier function in order to facilitate effective transport of molecules across the skin. This strategy involves use of micron sized needles fabricated of different materials and geometries to create transient aqueous conduits across the skin. MN, alone or with other enhancing strategies, has been demonstrated to dramatically enhance the skin permeability of numerous therapeutic molecules including biopharmaceuticals either in vitro, ex vivo or in vivo experiments. This suggested the promising use of MN technology for various possible clinical applications such as insulin delivery, transcutaneous immunisations and cutaneous gene delivery. MN has been proved as minimally invasive and painless in human subjects. This review article focuses on recent and future developments for MN technology including the latest type of MN design, challenges and strategies in MNs development as well as potential safety aspects based on comprehensive literature review pertaining to MN studies to date.
Antrodia camphorata is a parasitic fungus from Taiwan, it has been documented to possess a variety of pharmacological and biological activities. The present study was undertaken to evaluate the potential of Antrodia camphorata ethanol extract to accelerate the rate of wound healing closure and histology of wound area in experimental rats. The safety of Antrodia camphorata was determined in vivo by the acute toxicity test and in vitro by fibroblast cell proliferation assay. The scratch assay was used to evaluate the in vitro wound healing in fibroblast cells and the excision model of wound healing was tested in vivo using four groups of adult Sprague Dawley rats. Our results showed that wound treated with Antrodia camphorata extract and intrasite gel significantly accelerates the rate of wound healing closure than those treated with the vehicle. Wounds dressed with Antrodia camphorata extract showed remarkably less scar width at wound closure and granulation tissue contained less inflammatory cell and more fibroblast compared to wounds treated with the vehicle. Masson's trichrom stain showed granulation tissue containing more collagen and less inflammatory cell in Antrodia camphorata treated wounds. In conclusion, Antrodia camphorata extract significantly enhanced the rate of the wound enclosure in rats and promotes the in vitro healing through fibroblast cell proliferation.
A novel cross-linked honey hydrogel dressing was developed by incorporating Malaysian honey into hydrogel dressing formulation, cross-linked and sterilized using electron beam irradiation (25 kGy). In this study, the physical properties of the prepared honey hydrogel and its wound healing efficacy on deep partial thickness burn wounds in rats were assessed. Skin samples were taken at 7, 14, 21, and 28 days after burn for histopathological and molecular evaluations. Application of honey hydrogel dressings significantly enhanced (P < 0.05) wound closure and accelerated the rate of re-epithelialization as compared to control hydrogel and OpSite film dressing. A significant decrease in inflammatory response was observed in honey hydrogel treated wounds as early as 7 days after burn (P < 0.05). Semiquantitative analysis using RT-PCR revealed that treatment with honey hydrogel significantly (P < 0.05) suppressed the expression of proinflammatory cytokines (IL-1α, IL-1β, and IL-6). The present study substantiates the potential efficacy of honey hydrogel dressings in accelerating burn wound healing.
Background and Purpose. This study aimed to evaluate the wound healing activities of Aftamed and chlorine dioxide gels in streptozotocin-induced diabetic rats. Experimental Approach. Forty-eight Sprague Dawley rats were chosen for this study, divided into 4 groups. Diabetes was induced. Two-centimeter-diameter full-thickness skin excision wounds were created. Animals were topically treated twice daily. Groups 1, the diabetic control group, were treated with 0.2 mL of sterile distilled water. Group 2 served as a reference standard were treated with 0.2 mL of Intrasite gel. Groups 3 and 4 were treated with 0.2 mL of Aftamed and 0.2 mL of chlorine dioxide gels respectively. Granulation tissue was excised on the 10th day and processed for histological and biochemical analysis. The glutathione peroxidase ,superoxide dismutase activities and the malondialdehyde (MDA) levels were determined. Results. Aftamed-treated wounds exhibited significant increases in hydroxyproline, cellular proliferation, the number of blood vessels, and the level of collagen synthesis. Aftamed induced an increase in the free radical-scavenging enzyme activity and significantly reduced the lipid peroxidation levels in the wounds as measured by the reduction in the MDA level. Conclusions. This study showed that Aftamed gel is able to significantly accelerate the process of wound healing in diabetic rats.
Camellia sinensis (tea) is reported to have health benefits, including the building of healthy skin. This study evaluated the effects of topical application of Camellia sinensis extract on the rate of wound closure and the histology of wound area. A uniform area of 2.00 cm in diameter was excised from the neck of adult male Sprague Dawley rats. The animals were topically treated with 0.2 mL of vehicle (CMC), Intrasite gel (positive control), or 200 and 400 mg/mL of extract. Wounds dressed with the extract and Intrasite gel healed significantly earlier than those with vehicle. Histological analysis of the wound area after 10 days showed that wounds dressed with the extract had less scar width when compared to the control. The tissue contained less inflammatory cells and more collagen and angiogenesis, compared to wounds dressed with vehicle. In this study, Camellia sinensis showed high potential in wound healing activity.