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Mucoadhesive drug delivery systems have been extensively studied to effectively reduce the limitations of conventional drug delivery systems. Zein and polyvinyl pyrrolidone (PVP) are appraised for mucoadhesive properties. This study focuses on developing a mechanically stable zein/PVP electrospun membrane for propranolol hydrochloride (PL) transport. Fourier transform infrared, Raman spectra, and swelling studies gave evidence for PVP crosslinking, whereas circular dichroism spectroscopy revealed crosslinking of zein owing to the conformational change from α-helix to β-sheet. A 10 h thermal treatment of zein/PVP imparted 3.92 ± 0.13 MPa tensile strength to the matrix. Thermally crosslinked electrospun zein/PVP matrix showed 22.1 ± 0.1 g mm work of adhesion in porcine buccal mucosa tissue. Qualitative and quantitative evaluation of cytotoxicity in RPMI 2650 has been carried out. The in vitro drug release profile of PL from thermally crosslinked zein/PVP best fitted with the Korsmeyer-Peppas model. Immunostaining of β-catenin adherens junctional protein confirmed the absence of paracellular transport through the junctional opening. Still, drug permeation was observed through the porcine buccal mucosa, attributed to the transcellular transport of PL owing to its lipophilicity. The ex vivo permeation of PL through porcine buccal mucosa was also evaluated.

Generating electrospun mats with aligned fibers and obtaining neurite extension in the aligned fiber direction could provide hope for fabricating nerve guidance conduits or wraps through an easy method. The growing interest in generating electrospun mats with aligned fibers for tissue engineering is looking for simple methods to generate the same. Here, in this study, ethylene vinyl alcohol copolymer (EVAL) chains were complexed with silver ions (Ag

Electrospun zein membranes are suitable for various biomedical applications. A UV-crosslinked electrospun membrane of a zein/PEO blend for wound healing application was explored in this work. The improvement in mechanical properties of the membrane after UV crosslinking was attributed to the change in protein conformation from an α-helix to a β-sheet. The circular dichroism (CD) spectra and FTIR spectra confirmed this conformational change. XRD analysis was shown to prove the amorphous nature of polymer blends with specific broad peaks at 2θ = 9° and 20°. The water vapor transmission rate (WVTR) of the membrane was found to be in the range of 1500-2000 g m

Novel methods for the delivery of drugs other than the conventional method of oral administration have been a thrust area of research for a few decades. Mucoadhesive delivery of drugs opened up a new domain where rapid and patient-friendly delivery of drugs can be achieved. Delivery of drugs through the mucosal sites such as buccal, nasal, ocular, sublingual, rectal and vaginal facilitates bypassing the first-pass metabolism and the drug reaches the systemic circulation directly. This helps to increase the bioavailability of the drug. The study of the chemical characteristics of polymers with mucoadhesive properties and how the molecules or the pharmaceuticals are transported across the mucosa is very much needed for the advancement of research in this field. And at the same time, it is very pertinent to know about the anatomy and the physiology of the mucosal tissue and its variation in different regions of the body. In this review, we try to present a comprehensive understanding of relevant topics of mucoadhesion giving more emphasis on the mechanism of transport of drugs across mucosa, and different possible functional modifications of polymers to enhance the property of mucoadhesion.

Bone fractures associated with osteoporosis is a major concern all over the world especially among the elderly population and postmenopausal women. Bisphosphonates (BPs) are widely used clinically ...

Fabrication of a surface-engineered electrospun scaffold having biomimetic properties like the extracellular matrix (ECM) is essential for neural tissue engineering. An electroconductive and elastomeric scaffold with aligned fibers acting as a substrate may have a great impact on the directional outgrowth of neurites. In this study, we have electrospun electrically conductive, polyurethane-based elastomeric and topographically aligned fibro-porous neural scaffolds. Adhesive proteins of the ECM are documented to have an important role in controlling neuronal cell behavior, including cell adhesion, proliferation, and neurite outgrowth. These bio-adhesion proteins or nanomaterials mimicking their action, if used for surface modification of neural scaffolds, may have the potential to accelerate the nerve repair process. Thus, electrospun scaffolds fabricated were surface-engineered using a unique and modified single-step electrospraying technique to coat the scaffold surface with an exploratory bio-adhesion agent, a thin layer of graphene oxide (GO) films. The study was then carried out to determine if the GO-coated electrospun electroconductive polycarbonate urethane (PCU) substrate can improve the bio-interface attributes of these scaffolds or may alter the neurite outgrowth of PC-12 cells like any other bio-adhesion proteins. Therefore, the hybrid scaffolds with GO coatings were compared with similar scaffolds coated with poly-l-lysine (PLL) for neural cell adhesion, proliferation, and neurite extension. Neurite outgrowth studies showed that although the average neurite length was comparable on both GO- and PLL-coated surfaces, the length profile of neurites, when categorized based on length, showed an increased number of lengthier neurites on the GO-coated hybrid scaffolds. In particular, the study brings out an innovative surface engineering technique for the coating of GO on polymeric scaffolds. It may be further put together in designing of hybrid surfaces with nanotopographical biophysical cues on three-dimensional neural scaffolds, which in turn may stimulate an accelerated neuronal regeneration via providing an enhanced ECM like milieu.

Conjugation of biomolecules over membrane surfaces intended for blood contacting applications has been proven worthwhile for the improvement of their hemocompatibility. In conjunction with this factuality, this manuscript for the first time unveils the feasibility of bovine serum albumin (BSA) immobilization via polydopamine precursors on electrospun poly(ethylene-co-vinyl alcohol) (EVAL) leukodepletion filter membranes. The successful immobilization of different extents of BSA on EVAL membranes was endorsed by the Attenuated Total Reflectance—Fourier Transform Infrared (ATR-FTIR) Spectrum, variations in the wettability, electron microscopic images revealing the alterations in the fiber diameter and porousness of membranes. An interesting backlash was encountered in the in vitro plasma protein adsorption and in vitro platelet adhesion on the BSA-immobilized membranes as they exhibited a higher protein adsorption and lower platelet adhesion in comparison with neat EVAL. The infiltration of immobilized BSA to the leukodepletion capacity of those membranes was preliminarily studied by in vitro blood-material interactions followed by typical whole blood filtration of selected membranes. The data presented highlight that BSA moieties do not particularly affect the white blood cell (WBC) adhesion and platelet adhesion of EVAL membranes whereas resulted in a significantly higher red blood cell (RBC) recovery and decreased hemolysis under in vitro conditions. Accordingly, BSA-immobilized EVAL membranes were made to asymmetric leukodepletion filters; however, their further evaluation by whole blood filtration ensued that immobilization of BSA could not particularly enhance the overall whole blood leukodepletion efficacy of EVAL membranes.

The present work deals with the preparation and characterization of hybrid electrospun fibres of thermoplastic polyurethane/polydimethylsiloxane (TPU-PDMS) and spherical nanohydroxyapatite (nHap) for bone tissue engineering applications. The fiber morphology with interconnected pore network, hydrophilicity, and mechanical properties of electrospun compatibilized blends were markedly influenced by the presence of nHap. The nHap based nanocomposites showed improvement in static and dynamical mechanical properties. Furthermore, the tensile strength was increased by 150% with the addition of 5 wt% of nHap in TPU-PDMS blend due to its superior morphology. The enhancement in the dispersion of nHap in TPU-PDMS blend matrix even at higher concentration was confirmed by FESEM, and Micro-CT analysis. Morphology of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using human osteoblast-like cells (MG-63) proved all the scaffolds were non-cytotoxic. The TPU-PDMS scaffold with 5 wt% nHap showed the best performance regarding the cell viability, SBF bioactivity and hemocompatibility which makes its applicability in the fabrication of living bony constructs, especially for bone tissue interfaces.

Surface engineering of implantable devices involving polymeric biomaterials has become an essential aspect for medical implants. A surface enhancement technique can provide an array of unique surface properties that improve its biocompatibility and functionality as an implant. Polyurethane-based implants that have found extensively acclaimed usage as an implant in biomedical applications, especially in the area of cardiovascular devices, still lack any mechanism to ward off bacterial or platelet adhesion. To bring out such a defense mechanism we are proposing a surface modification technique. Graphene oxide (GO) in very thin film form was wrapped onto the electrospun fibroporous polycarbonate urethane (PCU) membrane (GOPCU) by a simple method of electrospraying. In the present study, we have developed a simple single-step method for coating a polymeric substrate with a thin GO film and evaluated the novel antiadhesive activity of these films. SEM micrographs after coating showed the presence of very thin GO films over the PCU membrane. On the GOPCU surface, the contact angle was shifted by ∼30°, making the hydrophobic PCU surface slightly hydrophilic, while Raman spectral characterization and mapping showed the presence and distribution of GO over 75% of the membrane. A reduced platelet adhesion on the GOPCU surface was observed; meanwhile, bacterial adhesion also got reduced by 85% for Staphylococcus aureus (Gram positive, cocci) and 64% for Pseudomonas aeruginosa (Gram negative, bacilli). A cell adhesion study conducted using mammalian fibroblast cells projected its proliferation percentage in a MTT assay, with 82% cell survival on PCU and 86% on GOPCU after 24 h culture, while a study for an extended period of 72 h showed 87% of survival on PCU and 88% on GOPCU. This plethora of functionalities by a simple modification technique makes thin GO films a self-sufficient surface engineering material for future biomedical applications.

The major motive of this investigation was to derive a correlation between surface functionality, wettability, and leukodepletion efficiency of electrospun filter media. Towards this, different extents of hydrophilicity and various functionalities were introduced to the electrospun poly (ethylene-co-vinyl alcohol) (EVAL) filter media via photografting of 2-hydroxyethyl acrylate (HEA) branches, photografting of N-(3-sulfopropyl)-N-methacroyloxyethyl-N,N- dimethylammonium betaine (SMDB) branches, and integration of glycine. All the filter media were designed to asymmetric filters with fiber sizes varying from 1.7 ± 0.2 μm to 2.4 ± 0.2 μm, pore sizes from 7.8 ± 1.5 μm to 23.3 ± 5.0 μm, water contact angles from 69 ± 10° to 134 ± 3 critical wetting surface tension (CWST) from 61.8 mN/m to > 88 mN/m and their performance was ascertained by carrying out whole blood filtration studies. It was observed that hydrophilic filter media resulted in a decreased adhesion of white blood cells (WBCs) than the unmodified EVAL filter media due the formation of a hydration layer. However, the hydrophilic SMDB grafted EVAL (PSMBD-g- EVAL) showed a high WBC adhesion than expected because of the net negative polarity of the PSMDB branches by which they could grasp the WBC even in presence of hydration layer. The efficacy of WBC adhesion by hydrophobic glycinated EVAL (EVAL-GLY) filter media was nearly as that of unmodified EVAL while the red blood cell (RBC) recovery was less pronounced (67 % lower than unmodified EVAL) due to the pore occlusion. However, there was no significant change in platelet adhesion for all filter media except PHEA-g-EVAL. Hemolysis induced by all the modified filter media was notably lesser than that of unmodified EVAL and was nearly zero. Thus, it is concluded that WBC and platelet adhesion are interdependent under dynamic conditions and it is difficult to achieve a selective adhesion of one in presence of the other.

Nanosheet type fillers apart from their size and surface functional groups may have numerous attributes affecting the mechanical properties of polymeric nanocomposites. To study these, silane-functionalized graphene based fillers were synthesized by chemically grafting N-[3-(trimethoxysilyl)propyl]diethylenetriamine (TMPT) onto graphene oxide (GO) and carboxylated GO (GOCO) using different chemistries. Their respective silanization yielded nano-fillers with amine (GOSAM) and alkoxy (GOCSAL) groups. Further, hydroiodic acid (HI) treatment led to synthesis of their reduced counterparts GRSAM and GRCSAL. The resulting TMPT-functionalized nanosheets were characterized by Fourier transform infrared spectroscopy (FT-IR) confirmed silane functionalization. A blue shift in Raman spectra indicated that during silanization with different terminal groups an inherent compressive strain has developed, while reduction with HI caused a red shift indicating a tensile strain, in these nanosheets. Polycarbonate urethane nanocomposite electrospun membranes (PCU) incorporated with these respective fillers at different loadings were analyzed. Morphology of the nanocomposite membranes was observed under SEM and membranes were characterized by static and dynamic mechanical analysis. The study indicated that the exfoliation and dispersion of graphene sheets in PCU has significantly improved due to surface functionalization while it also exhibited a novel aspect, variations in their mechanical properties in respect to the type of strain present in incorporated nanosheet fillers. The nanosheet fillers with compressive strain contributed more to the mechanical property enhancement of nanocomposite membranes, than the fillers with tensile strain. A spring and molecule model was thus proposed as possible explanation to relate inherent strain in filler to that of nanocomposite membrane mechanical properties. In vitro non-cytotoxic and hemocompatible nature of these fibroporous nanocomposite membranes provided their potential in biomedical applications.

Calcium-containing segmented polyurethane urea was synthesized using a calcium salt of p-aminobenzoic acid, polytetramethylene glycol, and 4,4′-methylene bis(cyclohexyl isocyanate) and thereafter fabricated into three-dimensional scaffolds for the use in biomedical applications. Biocompatibility evaluation of the polymer showed that this newly developed metal-containing polyurethane urea demonstrated good cytocompatibility and hemocompatibility. The fabricating ability of the metal-containing polymer was studied by the electrospinning process. The effect of various parameters such as polymer concentration, applied voltage, and flow rate on the electrospinning process, morphology, and diameter of the resultant fibers was investigated. The findings indicate that increasing the concentration and flow rate of the solution increases the fiber diameter. It was also demonstrated that increasing the applied voltage decreases the fiber diameter. Mechanical property evaluation of the scaffolds showed that the strength of the scaffold depends on both the diameter and morphology of the fibers. As the fiber diameter increases from 1.6 to 3.02 μm, the tensile strength enhanced from 3 to 7 MPa.

A fibro-porous wound dressing with antibacterial activity was fabricated from polycaprolactone (PCL) solution containing crude extract of biophytum sensitivum (BS) a potential antibacterial herbal drug. Scanning electron microscopy revealed the smooth fibrous morphology of the PCL membrane, whereas the drug-loaded PCL formed fibers with more interconnective junctions with an average fiber diameter between 1 and 3 μm. Physical characterization of the membrane revealed that it has excellent mechanical stability, water vapor transmission rate and that it promotes water uptake. The release characteristics by total immersion method in phosphate buffer and acetate buffer displayed an increase in drug release with time. Finally, the antibacterial activity of the membrane was tested against standard strains of Staphylococcus aureus and Escherichia coli. PCL membranes loaded with the drug extracts were able to inhibit the growth of bacterial strains which indicated that this fibro-porous membrane could act as a potential wound-dressing material to treat various wounds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

This paper presents several enhancements to existing methods of converting wireframe CAD models to surface representations. Existing methods consider only polyhedral objects. In these methods, closed loops of edges in the wireframe, which define the boundaries of planar surfaces, are first detected by a combination of topological and geometric techniques. The regions bounded within these edges are then approximated by a number of planar polygons. Enhancements described in this paper permit the algorithms to be extended to wireframes that describe objects with curved surfaces and surfaces with holes. An approach for tesselating curved surfaces is also described. With these enhancements, conversion methods can then be applied to arbitrary wireframes without imposing restrictions on the edges or surfaces that comprise the wireframes.