ISRN Biomaterials http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Reducing the Foreign Body Reaction by Surface Modification with Collagen/Hyaluronic Acid Multilayered Films Sun, 13 Apr 2014 14:37:44 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2014/718432/ Biological response against foreign implants often leads to encapsulation, possibly resulting in malfunction of implants devices. The aim of this study was to reduce the foreign body reaction by surface modification of biomaterials through layer-by-layer deposition of type I collagen (COL)/hyaluronic acid (HA) multilayer films. Polydimethylsiloxane (PDMS) samples were coated with alternative COL and HA layers with different layers. We found that the in vitro adhesion, proliferation, and activation of macrophage-like cells were greatly decreased by COL/HA multilayered deposition. The PDMS samples modified with 20 bilayers of COL/HA were implanted in rats for 3 weeks, and the thickness of encapsulation surrounding the samples was decreased by 29–57% compared to the control unmodified PDMS. This study demonstrates the potential of COL/HA multilayer films to reduce foreign body reaction. Cindy Yi Chi Hsieh, Fang-Wei Hu, Wen-Shiang Chen, and Wei-Bor Tsai Copyright © 2014 Cindy Yi Chi Hsieh et al. All rights reserved. Treatment of a Spinal Cord Hemitransection Injury with Keratin Biomaterial Hydrogel Elicits Recovery and Tissue Repair Sun, 23 Mar 2014 06:29:55 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2014/426047/ Medical care costs can reach an estimated value of $4 billion for spinal cord injuries (SCI) each year in the USA alone. With no viable treatment options available, care remains palliative and aims to minimize lifelong disabilities and complications, such as immobility, bladder and bowel dysfunction, breathing problems, and blood clots. Human hair keratin biomaterials have demonstrated efficacy in peripheral nerve injury models and were shown to improve conduction delay and increase axon number and density. In this study, a keratin hydrogel was tested in a central nervous system (CNS) application of spinal cord hemisection injury. Keratin-treated rats showed increased survival rates as well as a better functional recovery of gait properties and bladder function. Histological results demonstrated reduced glial scar formation with keratin treatment and suggested a greater degree of beneficial remodeling and cellular influx. The data provided in this pilot study suggest the possibility of using a keratin-based treatment for SCI and warrant further investigation. Bailey V. Fearing, Christopher Hartley, Orrin Dayton, Garrett Sherwood, Tamer AbouShwareb, and Mark E. Van Dyke Copyright © 2014 Bailey V. Fearing et al. All rights reserved. Effect of Synthesis Temperature on the Crystallization and Growth of In Situ Prepared Nanohydroxyapatite in Chitosan Matrix Mon, 24 Feb 2014 08:17:35 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2014/897468/ Hydroxyapatite nanoparticles (nHA) have been used in different biomedical applications where certain particle size distribution and morphology are required. Chitosan/hydroxyapatite (CS/HA) nanocomposites were prepared using in situ coprecipitation technique and the effect of the reaction temperature on the crystallization and particle growth of the prepared nanohydroxyapatite particles was investigated. The composites were prepared at different synthesis temperatures (−10, 37, and 60°C). XRD, FTIR, thermal analysis, TEM and SEM techniques were used to characterize the prepared specimens. It was found that the increase in processing temperature had a great affect on particle size and crystal structure of nHA. The low temperature (−10°C) showed inhabitation of the HA growth in c-direction and low crystallinity which was confirmed using XRD and electron diffraction pattern of TEM. Molar ratio of the bone-like apatite layer (Ca/P) for the nanocomposite prepared at 60°C was higher was higher than the composites prepared at lower temperatures (37 and −10°C). Habiba Elhendawi, R. M. Felfel, Bothaina M. Abd El-Hady, and Fikry M. Reicha Copyright © 2014 Habiba Elhendawi et al. All rights reserved. Evaluation of Three-Dimensional Porous Iron-Cross-Linked Alginate as a Scaffold for Cell Culture Thu, 06 Feb 2014 17:06:13 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2014/375758/ We investigated the efficacy of three-dimensional porous ferric-ion-cross-linked alginate (Fe-alginate) gels as cell scaffolds, in comparison with calcium-ion-cross-linked alginate (Ca-alginate) gels. In a previous study, we had demonstrated that two-dimensional Fe-alginate film was an efficient material for use as a scaffold, allowing good cell adhesion and proliferation, unlike Ca-alginate film. In the present study, we fabricated three-dimensional porous Fe- and Ca-alginate gels by freeze-drying and evaluated their effects on cultured cells. The Fe-alginate gels showed higher protein adsorption ability than Ca-alginate gels. Cells formed multicellular spheroids in both types of alginate scaffold, but the number of cultured cells increased with culture time on Fe-alginate porous gels, whereas those on Ca-alginate gels did not. Moreover, it was revealed that the cells on Fe-alginate scaffolds were still viable inside the multicellular spheroids even after cultivation for 14 days. These results suggest that Fe-alginate provides a superior porous scaffold suitable for three-dimensional culture of cells. Our findings may be useful for extending the application of Fe-alginate to diverse biomedical fields. Ikuko Machida-Sano, Sakito Ogawa, Makoto Hirakawa, and Hideo Namiki Copyright © 2014 Ikuko Machida-Sano et al. All rights reserved. Clinical and Radiographic Comparison of Oxidized Zirconium and Cobalt Chrome Femoral Components of a Single Design Primary Total Knee Arthroplasty: Is the Cost Difference Justified Based on Patient Outcomes? Wed, 04 Dec 2013 13:13:27 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/174298/ A review of 120 consecutive total knee arthroplasty patient records was made comparing oxidized zirconium with traditional cobalt chrome alloy femoral components and assessing the clinical and radiographic outcomes of each. The direct hospital implant cost for each of these implant systems was obtained and assessed in the context of any difference in patient Knee Society Scores, knee flexion, pain, probability of metal allergy, and radiographic signs of pending implant failures. At an average of 5.6-year followup (1–11-year range in both groups), the data showed no clinical or radiological variance between the two groups, while the hospital direct implant cost with the oxidized zirconium femoral component was $1900 higher than the cobalt chrome implants. Considering the cost difference between the implants and the lack of a difference in outcomes at an average of 5-6 years of followup, this paper brings into question the ability to justify the use of oxidized zirconium femoral components based solely on improved patient outcomes. Geevan George, Nicole Durig, Stewart Lee, Stephanie Tanner, Rebecca Snider, and Thomas Pace Copyright © 2013 Geevan George et al. All rights reserved. A Review of Surface Treatment Methods to Improve the Adhesive Cementation of Zirconia-Based Ceramics Thu, 10 Oct 2013 08:49:31 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/185376/ In spite of high mechanical strength, zirconia-based ceramics (ZrO2) has poor bond strength after conventional bond cementation procedures, requiring different surface treatment methods (STMs). This review gathered information about the STM for adhesive cementation (AC) to ZrO2 in the PubMed database, considering in vitro studies pertaining to AC for acid-resistant ceramics (ZrO2) limited to peer-reviewed papers published in English between 1965 and 2013 in dental journals. Different STMs have been proposed for ZrO2: air-abrasion (laboratory or chairside) with silica- (Si-) coated aluminum particles, the use of materials containing phosphate monomers, primer or silane application, laser irradiation, Si vapor phase deposition, and selective infiltration etching. In conclusion, STMs improve bond strength of resin luting cement to ZrO2 mainly when tested in short time. STMs must be correlated to the type of ZrO2 and the resin cement. Rodrigo Dalla Lana Mattiello, Tulio Marcos Kalife Coelho, Elizeu Insaurralde, Alan Augusto Kalife Coelho, Gustavo Pereira Terra, Amanda Vessoni Barbosa Kasuya, Isabella Negro Favarão, Luciano de Souza Gonçalves, and Rodrigo Borges Fonseca Copyright © 2013 Rodrigo Dalla Lana Mattiello et al. All rights reserved. Characterization of an In Vitro Model of Extracorporeal Circulation: A New Tool for Investigating the Pathophysiological and Therapeutic Strategies in Whole Blood Mon, 12 Aug 2013 09:11:33 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/640895/ A clinically relevant extracorporeal circulation model would be a valuable tool for investigating the pathophysiological and therapeutic strategies in whole blood. Previous models were limited by issues such as large circuit area; the inability to achieve full bypass; and donor blood requirement for prime. Here we established a miniature circuit to overcome these limitations consisting of a peristaltic pump, a test cell, a blood reservoir, and an oxygenator connected via polyvinylchloride and porous platinum silicon tubing. A heparinised (10 U/mL) saline solution at pH 7.4 was used to prime the circuit and the test cell was incubated in a water bath to maintain the temperature at 37°C. Blood flow through the circuit was at 5 mL/minute rate. Haemodynamics, haemoglobin concentration, and blood gases were analysed and the circuit performance was optimised according to the levels of haemolysis at three circulation time intervals: before the start, 30 minutes, and 60 minutes. No statistically significant haemodynamics and blood gases differences were observed. We have established a miniature extracorporeal circuit consisting of asanguineous prime for CPB model that maintains clinically acceptable results regarding hemodynamic parameters, blood gases, and haemodilution. This surrogate model would be important for further use in clinically pertinent research. Bashir M. Matata and Maqsood M. Elahi Copyright © 2013 Bashir M. Matata and Maqsood M. Elahi. All rights reserved. Amelogenin Peptide Extract Increases Differentiation and Angiogenic and Local Factor Production and Inhibits Apoptosis in Human Osteoblasts Thu, 01 Aug 2013 10:08:24 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/347318/ Enamel matrix derivative (EMD), a decellularized porcine extracellular matrix (ECM), is used clinically in periodontal tissue regeneration. Amelogenin, EMD’s principal component, spontaneously assembles into nanospheres in vivo, forming an ECM complex that releases proteolytically cleaved peptides. However, the role of amelogenin or amelogenin peptides in mediating osteoblast response to EMD is not clear. Human MG63 osteoblast-like cells or normal human osteoblasts were treated with recombinant human amelogenin or a 5 kDa tyrosine-rich amelogenin peptide (TRAP) isolated from EMD and the effect on osteogenesis, local factor production, and apoptosis assessed. Treated MG63 cells increased alkaline phosphatase specific activity and levels of osteocalcin, osteoprotegerin, prostaglandin E2, and active/latent TGF-β1, an effect sensitive to the effector and concentration. Primary osteoblasts exhibited similar, but less robust, effects. TRAP-rich 5 kDa peptides yielded more mineralization than rhAmelogenin in osteoblasts in vitro. Both amelogenin and 5 kDa peptides protected MG63s from chelerythrine-induced apoptosis. The data suggest that the 5 kDa TRAP-rich sequence is an active amelogenin peptide that regulates osteoblast differentiation and local factor production and prevents osteoblast apoptosis. Rene Olivares-Navarrete, Sharon L. Hyzy, Argelia Almaguer-Flores, Corinna Mauth, Anja C. Gemperli, Barbara D. Boyan, and Zvi Schwartz Copyright © 2013 Rene Olivares-Navarrete et al. All rights reserved. Viability of Titanium-Titanium Boride Composite as a Biomaterial Wed, 10 Jul 2013 10:56:56 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/970535/ The use of reinforcements to enhance mechanical properties of titanium such as hardness has been adopted by many researchers. Of these reinforcements, titanium boride has emerged as one of the most suitable reinforcements for titanium which is both chemically and mechanically compatible with the titanium matrix. Despite the extensive work conducted on these types of composites, very little is known about their biocompatibility which has so far precluded their use in bioapplications. The present paper investigates, for the first time, the biocompatibility of powder-processed titanium-titanium boride () composites for use in medical and dental implants and basic studies on fibroblast attachment conducted to assess for this application. The work is intended to serve as an initial step towards understanding the bioresponse of these composites by evaluating cytotoxicity, cellular attachment and morphology, and hemolytic potential. Results indicate that fibroblasts attach, proliferate, and achieve confluency when in contact with the composites, exhibiting normal morphology. Furthermore, the cells show a favorable growth rate when cultured with the composite for 48 hours. The composite demonstrated excellent blood biocompatibility, with a low hemolysis level (0.12% ) when compared with CP Ti (0.17%) and Ti-6Al-4V (0.36%). These findings suggest that composite is biocompatible and further investigation into its suitability as a biomaterial should be considered. F. M. Makau, K. Morsi, N. Gude, R. Alvarez, M. Sussman, and K. May-Newman Copyright © 2013 F. M. Makau et al. All rights reserved. Relative Contributions of Surface Roughness and Crystalline Structure to the Biocompatibility of Titanium Nitride and Titanium Oxide Coatings Deposited by PVD and TPS Coatings Sun, 16 Jun 2013 12:51:12 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/783873/ This study was conducted to characterize titanium (Ti) metal surfaces modified by polishing, coating with titanium nitride, coating with titanium oxide, sandblasting with alumina (Al2O3) particles and coating with titanium oxide, coating with titanium plasma spray (TPS); and to evaluate the effect of surface roughness and crystalline structure on adhesion of human fetal osteoblast cells (CRL-11372) in vitro after 24 hours. Surface topography and roughness were examined by scanning electron microscopy (SEM) and a noncontacting optical profilometer, respectively. The crystalline structures of the coatings were characterized by X-ray diffraction (XRD). CRL-11372 cells were incubated at these surfaces for 24 h and were evaluated for their mean total cell counts and cell viabilities. Cell morphologies were examined qualitatively by SEM images. Glass discs served as control group (CG) for the cell culture experiments. Surfaces at the Group TPS had the highest and values. Highest mean total cell counts were found for the CG. SC (sandblasted and TiO2 coated) surfaces had shown sparsely oriented CRL-11372 cells while other surfaces and CG showed confluency. Surfaces displayed diverse crystalline structures. Crystalline structures led to different cellular adhesion responses among the groups regardless of the surface roughness values. Sinem Yeniyol, Nilüfer Bölükbaşı, Ayhan Bilir, Ali Fuat Çakır, Mefail Yeniyol, and Tayfun Ozdemir Copyright © 2013 Sinem Yeniyol et al. All rights reserved. Platelet-Rich Fibrin as a Biofuel for Tissue Regeneration Thu, 06 Jun 2013 13:31:42 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/627367/ Wound healing is a staged process which involves the activity of leukocytes and platelets. For this process to work efficiently, the platelets play a vital role. The growth factors present in platelets are important to guide the regenerating cells to the area of healing. Platelet-rich-fibrin (PRF) is one such material that holds on to these growth factors enmeshed in the fibrin network resulting in their sustained release over a period of time that can accelerate the wound healing process. With this knowledge, research has been carried out for a past few years for the clinical application of PRF. Various platelet concentrates have been studied including the platelet-rich-plasma (PRP). However, the short duration of cytokine release and its poor mechanical properties have resulted in the search of a new material with adequate properties for clinical application and ease of preparation. PRF has found a place in the regenerative field owing to its advantages over PRP. This review focuses on the properties and various applications of PRF in the clinical practice. Sujeet Vinayak Khiste and Ritam Naik Tari Copyright © 2013 Sujeet Vinayak Khiste and Ritam Naik Tari. All rights reserved. Mechanical Properties of Enamel Nanocomposite Tue, 09 Apr 2013 10:42:47 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/253761/ For adult Indian premolar teeth, we report for the first time ever the simultaneous evaluations of nanohardness, Young's modulus, and fracture toughness of the enamel nanocomposite. The nanohardness and Young's moduli were evaluated from near the beginning of the middle enamel region to within 10 μm of the dentino-enamel junction (DEJ) and in the dentin region using the nanoindentation technique. The fracture toughness from near the middle of the enamel region to near the DEJ zone was measured using the microindentation technique. The deformation was studied using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). The relative differences in the extents of biomineralization in the enamel and dentin regions were studied by the energy dispersive X-ray (EDS) technique. The variations of the toughness of the enamel as a function of the toughness of the protein matrix phase have been analyzed which showed that the predicted value of the toughness of the protein present in the nanocomposite was comparable to that of other bioproteins reported in the literature. Further, the work of fracture estimated from the measured value of toughness of the enamel nanocomposite agreed well with the experimental data reported in the literature. Nilormi Biswas, Arjun Dey, Saugata Kundu, Himel Chakraborty, and Anoop K. Mukhopadhyay Copyright © 2013 Nilormi Biswas et al. All rights reserved. Bioprosthetic Heart Valves: Impact of Implantation on Biomaterials Tue, 12 Mar 2013 13:02:48 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/728791/ Prosthetic heart valves are commonly used in the treatment of valvular heart disease. Mechanical valves are more durable than the bioprosthetic valves; however, the need for long-term anticoagulant therapy renders them unsuitable for some patient groups. In this paper we discuss the different types and models of bioprosthesis, and in particular, pericardial bioprosthesis. We also discuss the preimplantation preparation processes, as well as their postimplantation changes and modes of failure. Pooja Singhal, Adriana Luk, and Jagdish Butany Copyright © 2013 Pooja Singhal et al. All rights reserved. Influence of Surface Treatments on the Bioactivity of Ti Tue, 01 Jan 2013 09:22:35 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/205601/ Several techniques have been described to modify the surface of titanium to make it more bioactive. Heat treatment (HT) and sodium hydroxide treatment (NaOH) have been used and can change the crystallinity and surface chemistry of titanium implants. However, no studies have systemically focused on comparing these different methods and their effect on the bioactivity of Ti. Therefore, in this study, Ti substrates were systematically treated using HT, NaOH, and a combination of HT and NaOH. The Ti plates were heat treated at various temperatures, and the plates were subjected to HT followed by soaking in NaOH or first soaked in NaOH and then heat treated. The morphology, crystallinity, hardness, water contact angle, and surface energy of the samples were analyzed as well as the bioactivity after immersion in PBS. Morphology and crystallinity changed with increasing temperature. The difference was most pronounced for the 800°C treated samples. The water contact angle decreased, and the surface energy increased with increasing temperature and was highest for 800°C. The rutile surface showed faster hydroxyapatite formation. NaOH treatment of the HT Ti samples increased the surface energy and improved its bioactivity further. Also, HT of NaOH samples improved the bioactivity compared to only HT. Carl Lindahl, Håkan Engqvist, and Wei Xia Copyright © 2012 Carl Lindahl et al. All rights reserved. Strontium Incorporated Coralline Hydroxyapatite for Engineering Bone Wed, 12 Dec 2012 14:52:08 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/649163/ Goniopora was hydrothermally converted to coralline hydroxyapatite (CHA) and incorporated with Sr (Sr-CHA). The pore size of Goniopora was in the range of 40–300 μm with a porosity of about 68%. Surface morphologies of the coral were modified to flake-like hydroxyapatite structures on CHA and the addition of Sr detected on Sr-CHA as confirmed by SEM and EDX. As the first report of incorporating Sr into coral, about 6%–14% Sr was detected on Sr-CHA. The compressive strengths of CHA and Sr-CHA were not compromised due to the hydrothermal treatments. Sr-CHA was studied in vitro using MC3T3-E1 cells and in vivo with an ovariectomized rat model. The proliferation of MC3T3-E1 cells was significantly promoted by Sr-CHA as compared to CHA. Moreover, higher scaffold volume retention (+40%) was reported on the micro-CT analysis of the Sr-CHA scaffold. The results suggest that the incorporation of Sr in CHA can further enhance the osteoconductivity and osteoinductivity of corals. Strontium has been suggested to stimulate bone growth and inhibit bone resorption. In this study, we have successfully incorporated Sr into CHA with the natural porous structure remained and explored the idea of Sr-CHA as a potential scaffolding material for bone regeneration. Waiching Liu, Ting Wang, Yuhui Shen, Haobo Pan, Songlin Peng, and William W. Lu Copyright © 2012 Waiching Liu et al. All rights reserved. Micro-Pop-In Issues in Nanoscale Contact Deformation Resistance of Tooth Enamel Tue, 27 Nov 2012 08:17:22 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/545791/ Human tooth enamel is a natural nanocomposite with a hierarchical structural architecture that spans from macroscale to nanoscale. Thus it offers the unique opportunity to study the physics of deformation at the nanoscale in a controlled manner using the novel nanoindentation technique. In spite of the wealth of literature, however, the information about the effect of loading rate on the nanoindentation behavior of human tooth enamel is far from being significant. Therefore, the major objective of the present work was to study the loading rate effect on nanoindentation behavior of enamel with a view to improve our understanding that could be used for development of better bioinspired synthetic structures for functional as well as biomedical utilities. The nanoindentation experiments were conducted at loading rates in the range of to   at peak load of   at room temperature with a Berkovich tip on the longitudinal section from a freshly extracted premolar tooth enamel surface from a 65-year-old Indian male. To the best of our knowledge here we report for the first time the experimental observation of the increase in intrinsic resistance against contact-induced deformation at the nanoscale with the loading rate applied to the enamel surface. The results were explained by considering the microstructural details and the shear stress underneath the nanoindenter. Nilormi Biswas, Arjun Dey, and Anoop Kumar Mukhopadhyay Copyright © 2013 Nilormi Biswas et al. All rights reserved. Effects of Heat Treatment on the Mechanical and Degradation Properties of 3D-Printed Calcium-Sulphate-Based Scaffolds Mon, 26 Nov 2012 15:26:49 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/750720/ Three-dimensional printing (3DP) has been employed to fabricate scaffolds with advantages of fully controlled geometries and reproducibility. In this study, the scaffold structure design was established through investigating the minimum feature size and powder size distribution. It was then fabricated from the 3DP plaster-based powders (CaSO4·1/2H2O). Scaffolds produced from this material demonstrated low mechanical properties and a rapid degradation rate. This study investigated the effects of heat treatment on the mechanical and in vitro degradation properties of the CaSO4 scaffolds. The occurrence of dehydration during the heating cycle offered moderate improvements in the mechanical and degradation properties. By using a heat treatment protocol of 200°C for 30 min, compressive strength increased from 0.36 ± 0.13 MPa (pre-heat-treated) to 2.49 ± 0.42 MPa (heat-treated). Heat-treated scaffolds retained their structure and compressive properties for up to two days in a tris-buffered solution, while untreated scaffolds completely disintegrated within a few minutes. Despite the moderate improvements observed in this study, the heat-treated CaSO4 scaffolds did not demonstrate mechanical and degradation properties commensurate with the requirements for bone-tissue-engineering applications. Zuoxin Zhou, Christina A. Mitchell, Fraser J. Buchanan, and Nicholas J. Dunne Copyright © 2013 Zuoxin Zhou et al. All rights reserved. Tooth-Implant Connection: A Review Sun, 21 Oct 2012 07:53:34 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/921645/ Connecting teeth to osseointegrated implants presents a biomechanical challenge. This is due to the implant being rigidly fixed to the bone and the tooth being attached to the bone with a periodontal ligament. In order to overcome this problem, various connection types such as rigid and nonrigid have been proposed. However, the mechanism of attachment and the perceived problem of the differential support provided by the implant and the tooth have been discussed by many authors, and the ideal connection type is still controversial. The aim of this study was to carry out a review of all available literature addressing the tooth-implant connection and evidence-based understanding of the management of tooth-implant-retained restorations. Serhat Ramoglu, Simge Tasar, Selim Gunsoy, Oguz Ozan, and Gokce Meric Copyright © 2013 Serhat Ramoglu et al. All rights reserved. Chitosan-Carrageenan Polyelectrolyte Complex for the Delivery of Protein Drugs Thu, 13 Sep 2012 13:46:27 +0000 http://www.hindawi.com/journals/isrn.biomaterials/2013/629807/ A chitosan-carrageenan polyelectrolyte complex (PEC) was prepared by salt induced impeding of polyplex formation method and was encapsulated with bovine serum albumin (BSA) to study the potential to be tailored to the pH responsive oral delivery of protein drugs. The FTIR spectra showed the successful formation of the PEC under the experimental condition. The release kinetics of BSA from the PEC was studied in the simulated gastrointestinal fluids with and without digestive enzymes. The prepared PEC showed the nature of pH-sensitivity. A typical controlled release of BSA from the PEC (180 μg of BSA from 3 mg of PEC) was obtained in the simulated intestinal fluid (SIF, pH 7.5), which was due to the significant swelling and disintegration of PEC, but little amount of BSA was released (11 μg of BSA from 3 mg of PEC) in the simulated gastric fluid (SGF, pH 1.2), confirming acidic stability of the prepared PEC. The presence of digestive enzymes was found not to affect the response of PEC to ambient pH value, but to speed up the release of BSA from carriers. Cunben Li, San Hein, and Kean Wang Copyright © 2013 Cunben Li et al. All rights reserved.