Gelatin-polytrimethylene carbonate blend based electrospun tubular construct as a potential vascular biomaterial.

The present work details the fabrication of electrospun tubular scaffolds based on the biocompatible and unexploited blend of gelatin and polytrimethylene carbonate (PTMC) as a media (middle layer of blood vessel) equivalent for blood vessel regeneration. An attempt to resemble the media stimulated the selection of gelatin as a matrix (substitution for collagen) with the inclusion of the biodegradable elastomer PTMC (substitution for elastin). -The work highlights the variation of electrospinning parameters and its assiduous selection based on fiber diameter distribution and pore size distribution to obtain smooth microfibers and micropores which is reported for the first time for this blend. Electrospun conduits of gelatin-PTMC blend had fibers sized 6-8 µm and pores sized ~100-150 µm. Young's modulus of 0.40 ±â€¯0.045 MPa was observed, resembling the tunica media of the native artery (~0.5 MPa). An evaluation of the surface properties, topography, and mechanical properties validated its physical requirements for inclusion in a vascular graft. Preliminary biological tests confirmed its minimal in-vitro toxicity and in-vivo biocompatibility. MTT assay (indirect) elucidated cell viability above 70% with scaffold extract, considered to be non-toxic according to the EN ISO-10993-5/12 protocol. The in-vivo subcutaneous implantation in rat showed a marked reduction in macrophages within 15 days revealing its biocompatibility and its possibility for host integration. This comprehensive study presents for the first time the potential of microporous electrospun gelatin and PTMC blend based tubular construct as a potential biomaterial for vascular tissue engineering. The proposed media equivalent included in a bilayer or trilayer polymeric construct can be a promising off-shelf vascular graft.

Development of an orthosis for simultaneous three-dimensional correction of clubfoot deformity.

BACKGROUND: Clubfoot is a three-dimensional deformity of the foot in which the foot is twisted in three mutually perpendicular planes from the normal shape of the foot. Of the various treatment methods that are available to manage clubfoot, non-operative approaches are preferred. The conventional non-operative method of treatment is to apply a series of casts to the infant's clubfoot to gradually manipulate its position. However, prolonged use of casts can result in skin rash, skin dehydration and ulcers on the soft skin of an infant. Treatment using orthosis represents an alternative non-operative and convenient technique because an orthosis can be put on and taken off at any time. METHODS: In the present study, an orthosis was developed according to the rotation of three mutually perpendicular planes and was subsequently tested on five patients over the duration of one week. FINDINGS: In all five cases, the desired incremental correction to the clubfoot was achieved through the one week intervention with the orthosis. No form of rash, dehydration, ulcers, and so on were observed on the skin of any baby involved in the study during or following application of the orthosis. INTERPRETATION: By using the developed orthosis, partial correction of the clubfoot deformity was achieved over a short period of time. However the widespread use of this device for extended durations and with a larger number of patients will generate further evidence of the extent to which this orthosis can reliably treat clubfoot.

Gelatin - Oxidized carboxymethyl cellulose blend based tubular electrospun scaffold for vascular tissue engineering.

The present work deals with the fabrication of electrospun tubular scaffold based on in-situ crosslinked blend of gelatin - oxidized carboxymethyl cellulose (OCMC) for vascular tissue engineering. The flow behavior and spinability of the hydrogel despite the in-situ crosslinked gelatin chains evaluated by Raman spectroscopic studies and rheological studies was utilized for electrospinning. The study highlights the tunable pore size and fiber diameter of the nanofibers with the manipulation of electrospinning parameters. With a future perspective of vascular tissue engineering, the electrospinning parameters yielding smooth bead free fibers and maximum magnitude in pore size and fiber diameter as well their homogenous distribution were selected for the fabrication of tubular constructs which is rarely reported. The surface and mechanical properties were evaluated to validate its properties to the native vessel. Biocompatibility was studied in vitro with BALB/c 3T3 cells and in vivo after subcutaneous implantation in rats. MTT assay confirmed its no-toxicity and no abnormal foreign body reaction were observed by 7 and 15days after implantation. Crosslinking with biocompatible crosslinker OCMC has rendered insolubility to gelatin yet making it spinable for electrospinning to fabricate porous, nanofibrous vascular biomaterial.

Design and evaluation of acrylate polymeric carriers for fabrication of pH-sensitive microparticles.

Colon-targeted microparticles loaded with a model anti-inflammatory drug were fabricated using especially designed acrylic acid-butyl methacrylate copolymers. Microparticles were prepared by oil-in-oil solvent evaporation method using Span 80 as emulsifier. Microparticles were found to be spherical in shape, hemocompatible and anionic with zeta potential of -27.4 and -29.0 mV. Entrapment of drug in the microparticles was confirmed by Fourier transform infrared (FTIR) spectroscopy. However, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) revealed amorphous nature of microparticles due to the dilution effect of amorphous polymer. The microparticles released less than 5% drug at pH 1.2, while more than 90% of the drug load was released at pH 7.4. This suggested the colon targeting nature of the formulations. In experimentally developed colitis in Wistar rats, the microparticle formulation showed significant reduction (p < .05) in the disease activity score (disease symptoms), the colon-to-body weight ratio (tissue edema) and the myeloperoxidase, tumor necrosis factor (TNF)-α and interleukin (IL)-1ß activities.

Cytotoxic evaluation of hydroxyapatite-filled and silica/hydroxyapatite-filled acrylate-based restorative composite resins: An in vitro study.

STATEMENT OF PROBLEM: Although the physical and mechanical properties of hydroxyapatite-filled dental restorative composite resins have been examined, the biocompatibility of these materials has not been studied in detail. PURPOSE: The purpose of this in vitro study was to analyze the toxicity of acrylate-based restorative composite resins filled with hydroxyapatite and a silica/hydroxyapatite combination. MATERIAL AND METHODS: Five different restorative materials based on bisphenol A-glycidyl methacrylate (bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) were developed: unfilled (H0), hydroxyapatite-filled (H30, H50), and silica/hydroxyapatite-filled (SH30, SH50) composite resins. These were tested for in vitro cytotoxicity by using human bone marrow mesenchymal stromal cells. Surface morphology, elemental composition, and functional groups were determined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The spectra normalization, baseline corrections, and peak integration were carried out by OPUS v4.0 software. RESULTS: Both in vitro cytotoxicity results and SEM analysis indicated that the composite resins developed were nontoxic and supported cell adherence. Elemental analysis with EDX revealed the presence of carbon, oxygen, calcium, silicon, and gold, while the presence of methacrylate, hydroxyl, and methylene functional groups was confirmed through FTIR analysis. CONCLUSIONS: The characterization and compatibility studies showed that these hydroxyapatite-filled and silica/hydroxyapatite-filled bis-GMA/TEGDMA-based restorative composite resins are nontoxic to human bone marrow mesenchymal stromal cells and show a favorable biologic response, making them potential biomaterials.

Design and development of a device to measure the deformities of clubfoot.

Clubfoot describes a range of foot abnormalities usually present at birth, in which the foot of a baby is twisted out of shape or position. In order to develop an effective treatment plan for clubfoot and/or assess the extent to which existing interventions are successful, medical practitioners need to be able to accurately measure the nature and extent of the deformity. This is typically performed using a goniometer. However, this device is only able to measure one dimension at a time. As such, a complete assessment of the condition of a foot can be extremely burdensome and time-consuming. This article describes a new device that can quickly and efficiently take several measurements on feet of various sizes and shapes. The use of this device was verified by measuring the deformities of real clubfeet. A silicone rubber clubfoot model was also used in this study to clearly illustrate the effectiveness with which the proposed device can measure the various deformities of clubfoot. It is envisaged that the use of this device will significantly reduce the time and effort orthopedists require to measure clubfoot deformities and develop and assess treatment plans.

Bioprintable, cell-laden silk fibroin-gelatin hydrogel supporting multilineage differentiation of stem cells for fabrication of three-dimensional tissue constructs.

Bioprinting has exciting prospects for printing three-dimensional (3-D) tissue constructs by delivering living cells with appropriate matrix materials. However, progress in this field is currently extremely slow due to limited choices of bioink for cell encapsulation and cytocompatible gelation mechanisms. Here we report the development of clinically relevant sized tissue analogs by 3-D bioprinting, delivering human nasal inferior turbinate tissue-derived mesenchymal progenitor cells encapsulated in silk fibroin-gelatin (SF-G) bioink. Gelation in this bioink was induced via in situ cytocompatible gelation mechanisms, namely enzymatic crosslinking by mushroom tyrosinase and physical crosslinking via sonication. Mechanistically, tyrosinases oxidize the accessible tyrosine residues of silk and/or gelatin into reactive o-quinone moieties that can either condense with each other or undergo nonenzymatic reactions with available amines of both silk and gelatin. Sonication alters the hydrophobic interaction and accelerates self-assembly of silk fibroin macromolecules to form ß-sheet crystals, which physically crosslink the hydrogel. However, sonication has no effect on the conformation of gelatin. The effect of optimized rheology, secondary conformations of silk-gelatin bioink, temporally controllable gelation strategies and printing parameters were assessed to achieve maximum cell viability and multilineage differentiation of the encapsulated human nasal inferior turbinate tissue-derived mesenchymal progenitor cells. This strategy offers a unique path forward in the direction of direct printing of spatially customized anatomical architecture in a patient-specific manner.

Culture & differentiation of mesenchymal stem cell into osteoblast on degradable biomedical composite scaffold: In vitro study.

BACKGROUND & OBJECTIVES: There is a significant bone tissue loss in patients from diseases and traumatic injury. The current autograft transplantation gold standard treatment has drawbacks, namely donor site morbidity and limited supply. The field of tissue engineering has emerged with a goal to provide alternative sources for transplantations to bridge this gap between the need and lack of bone graft. The aim of this study was to prepare biocomposite scaffolds based on chitosan (CHT), polycaprolactone (PCL) and hydroxyapatite (HAP) by freeze drying method and to assess the role of scaffolds in spatial organization, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs) in vitro, in order to achieve bone graft substitutes with improved physical-chemical and biological properties. METHODS: Pure chitosan (100CHT) and composites (40CHT/HAP, 30CHT/HAP/PCL and 25CHT/HAP/PCL scaffolds containing 40, 30, 25 parts per hundred resin (phr) filler, respectively) in acetic acid were freeze dried and the porous foams were studied for physicochemical and in vitro biological properties. RESULTS: Scanning electron microscope (SEM) images of the scaffolds showed porous microstructure (20-300 µm) with uniform pore distribution in all compositions. Materials were tested under compressive load in wet condition (using phosphate buffered saline at pH 7.4). The in vitro studies showed that all the scaffold compositions supported mesenchymal stem cell attachment, proliferation and differentiation as visible from SEM images, [3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay, alkaline phosphatase (ALP) assay and quantitative reverse transcription (qRT)-PCR. INTERPRETATION & CONCLUSIONS: Scaffold composition 25CHT/HAP/PCL showed better biomechanical and osteoinductive properties as evident by mechanical test and alkaline phosphatase activity and osteoblast specific gene expression studies. This study suggests that this novel degradable 3D composite may have great potential to be used as scaffold in bone tissue engineering.

Strategies for replicating anatomical cartilaginous tissue gradient in engineered intervertebral disc.

A critical challenge in fabricating a load bearing tissue, such as an intervertebral disc, is to simulate cellular and matrix alignment and anisotropy, as well as a specific biochemical gradient. Towards this goal, multilamellar silk fibroin scaffolds having criss-cross fibrous orientation were developed, where silk fibers in inner layers were crosslinked with bioactive molecule chondroitin sulfate. Upon culturing goat articular chondrocytes under static and dynamic conditions, lamellar scaffold architecture guided alignment of cells and the newly synthesized extracellular matrix (ECM) along the silk fibers. The dynamic culture conditions further improved the cellular metabolic rate and ECM production. Further the synergistic effect of chemical composition of scaffold and hydrodynamic environment of bioreactor contributed in developing a tissue gradient within the constructs, with an inner region rich in collagen II, glycosaminoglycan (GAG), and stiffer in compression, whereas an outer region rich in collagen I and stiffer in tension. Therefore, a unique combination of chemical and physical parameters of engineered constructs and dynamic culture conditions provides a promising starting point to further improve the system towards replicating the anatomical structure, composition gradient, and function of intervertebral disc tissue.

Combined miRNA and mRNA signature identifies key molecular players and pathways involved in chikungunya virus infection in human cells.

Since its discovery, Chikungunya fever caused by a virus (CHIKV) has ravaged most of Africa and Southeast Asia. Despite there being more than a million reported cases in India alone and the seriousness of the disease in the chronic phase, a clear understanding of the disease pathogenesis and host response remains elusive. Here, we use microarray technology and quantitative PCR method to establish the complete miRNA, snoRNA and mRNA signature of host response upon CHIKV infection in human cell line infection model, HEK293T. The results were further validated in human primary cells (dermal fibroblasts). miRNA expression profiling revealed regulation of 152 miRNAs post CHIKV infection. An interesting overlap in miRNA signature was seen majorly with HCV, HPV and HIV1 virus. The microarray data further validated by qRT-PCR revealed induction of miR-744, miR-638, miR-503 and others among the top upregulated miRNAs. Notably, we found induction of snoRNAs belonging to C/D cluster including close paralogs of U3, U44, U76 and U78 snoRNAs. Genes were found to be differentially expressed along 3 major pathways; TGF-ß, endocytosis and the cell cycle pathways. qRT-PCR data confirmed strong induction of TGF-ß (SMAD6, JUN, SKIL) and endocytosis pathway (CXCR4, HSPA8, ADRB1) genes while downregulation of cell cycle genes (CDC27 and CDC23). Interestingly, use of TGF-ß inhibitor, SB-431542, increased CHIKV mediated cell death. Overall, this study aims at providing the first complete transcriptome signature of host response upon CHIKV infection to aid identification of possible biomarkers and therapeutic targets.

The role of 3D structure and protein conformation on the innate and adaptive immune responses to silk-based biomaterials.

We have investigated monocyte and T cell responsiveness to silk based biomaterials of different physico-chemical characteristics. Here we report that untransformed CD14+ human monocytes respond to overnight exposure to silk fibroin-based biomaterials in tridimensional form by IL-1ß and IL-6, but not IL-10 gene expression and protein production. In contrast, fibroin based materials in bidimensional form are unable to stimulate monocyte responsiveness. The elicitation of these effects critically requires contact between biomaterials and responding cells, is not sustained and becomes undetectable in longer term cultures. We also observed that NF-κß and p38 MAP kinase play key roles in monocyte activation by silk-based biomaterials. On the other hand, fibroin based materials, irrespective of their physico-chemical characteristics appeared to be unable to induce the activation of peripheral blood T cells from healthy donors, as evaluated by the expression of activation markers and IFN-γ gene.

Enhanced redifferentiation of chondrocytes on microperiodic silk/gelatin scaffolds: toward tailor-made tissue engineering.

Direct-write assembly allows rapid fabrication of complex three-dimensional (3D) architectures, such as scaffolds simulating anatomical shapes, avoiding the need for expensive lithographic masks. However, proper selection of polymeric ink composition and tailor-made viscoelastic properties are critically important for smooth deposition of ink and shape retention. Deposition of only silk solution leads to frequent clogging due to shear-induced ß-sheet crystallization, whereas optimized viscoelastic property of silk-gelatin blends facilitate the flow of these blends through microcapillary nozzles of varying diameter. This study demonstrates that induction of controlled changes in scaffold surface chemistry, by optimizing silk-gelatin ratio, can govern cell proliferation and maintenance of chondrocyte morphology. Microperiodic silk-gelatin scaffolds can influence postexpansion redifferentiation of goat chondrocytes by enhancing Sox-9 gene expression, aggregation, and driving cartilage matrix production, as evidenced by upregulation of collagen type II and aggrecan expression. The strategy for optimizing redifferentiation of chondrocytes can offer valuable consideration in scaffold-based cartilage repair strategies.

Oriented lamellar silk fibrous scaffolds to drive cartilage matrix orientation: towards annulus fibrosus tissue engineering.

A novel design of silk-based scaffold is developed using a custom-made winding machine, with fiber alignment resembling the anatomical criss-cross lamellar fibrous orientation features of the annulus fibrosus of the intervertebral disc. Crosslinking of silk fibroin fibers with chondroitin sulphate (CS) was introduced to impart superior biological functionality. The scaffolds, with or without CS, instructed alignment of expanded human chondrocytes and of the deposited extracellular matrix while supporting their chondrogenic redifferentiation. The presence of CS crosslinking could not induce statistically significant changes in the measured collagen or glycosaminoglycan content, but resulted in an increased construct stiffness. By offering the combined effect of cell/matrix alignment and chondrogenic support, the silk fibroin scaffolds developed with precise fiber orientation in lamellar form represent a suitable substrate for tissue engineering of the annulus fibrosus part of the intervertebral disc.

Soluplus--solubilized citrated camptothecin--a potential drug delivery strategy in colon cancer.

Camptothecin (CPT), a potent antitumor drug, exhibits poor aqueous solubility and rapid conversion from the pharmacologically active lactone form to inactive carboxylate form at physiological pH. Solid dispersion of CPT in Soluplus®, an amphiphilic polymeric solubilizer, was prepared to increase the aqueous solubility of CPT and the resultant solid dispersion along with citric acid was formulated as hard gelatin capsules that were subsequently coated with Eudragit S100 polymer for colonic delivery. FTIR spectrum of the solid dispersion confirmed the presence of CPT. PXRD and DSC revealed the semicrystalline nature of solid dispersion. The solubility of the drug was found to increase ~40 times in the presence of Soluplus and ~75 times in solid dispersion. The capsules showed no drug release in 0.01 N HCl but released 86.4% drug in lactone form in phosphate buffer (pH 7.4) and the result appears to be due to citric acid-induced lowering of pH of buffer from 7.4 to 6.0. Thus the presence of citric acid in the formulation led to stabilization of the drug in its pharmacologically active lactone form. Cytotoxicity studies conducted with the formulation of solid dispersion with citric acid, utilizing cell cytotoxicity test (MTT test) on Caco-2 cells, confirmed cytotoxic nature of the formulation.

The quest for targeted delivery in colon cancer: mucoadhesive valdecoxib microspheres.

The aim of the present study was to prepare valdecoxib, a cyclo-oxygenase-2 enzyme inhibitor, as a loaded multiparticulate system to achieve site-specific drug delivery to colorectal tumors. Film coating was done with the pH-sensitive polymer Eudragit S100 and sodium alginate was used as mucoadhesive polymer in the core. The microspheres were characterized by X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy and were evaluated for particle size, drug load, in vitro drug release, release kinetics, accelerated stability, and extent of mucoadhesion. The coated microspheres released the drug at pH 7.4, the putative parameter for colonic delivery. When applied to the mucosal surface of freshly excised goat colon, microspheres pretreated with phosphate buffer pH 7.4 for 30 minutes showed mucoadhesion. To ascertain the effect of valdecoxib on the viability of Caco-2 cells, the 3-(4,5-dimethylthiazol-2yl) 2,5-diphenyltetrazolium bromide) test was conducted using both valdecoxib and coated microspheres. In both cases, the percentage of dehydrogenase activity indicated a lack of toxicity against Caco-2 cells in the tested concentration range. Drug transport studies of the drug as well as the coated microspheres in buffers of pH 6 and 7.4 across Caco-2 cell monolayers were conducted. The microspheres were found to exhibit slower and delayed drug release and lower intracellular concentration of valdecoxib.

Improved immunogenicity of biodegradable polymer particles entrapped rotavirus vaccine.

Rotavirus (RV) entrapped in polylactide (PLA) and polylactide-coglycolide (PLGA) polymer particles were formulated and evaluated in mice for improved immunogenicity using oral, intranasal (IN), and intramuscular (IM) routes of administration. Microparticles of size ranges between 1 and 8 µm were prepared using double emulsion solvent evaporation technique. Stabilizers like mouse serum albumin, sucrose, and sodium bicarbonate that were used during particle formulation helped in minimizing the denaturation of the entrapped antigen. Immunization with 20 µg of antigen entrapped in polymeric particles through various routes of administration elicited measurable amount of antibody titer in mice. The immunoglobulin A (IgA) and immunoglobulin G (IgG) titer (≥4-fold rise between pre and post immunized sera) was analyzed by the use of enzyme-linked immunosorbent assay. PLGA encapsulated RV microparticles elicited better antibody response through IN route (90%) where as PLA encapsulated RV microparticles showed improved response when administrated through oral route (83.3%). Overall, the performance of IN route based immunization was significantly higher than oral and IM route ( p<0.001) with both the polymers. The results are of indication that, PLGA encapsulated RV microparticles have greater potential for vaccine formulation to combat rotavirus infection.

Development of a new polypropylene-based suture: plasma grafting, surface treatment, characterization, and biocompatibility studies.

Polypropylene sutures (PP) are already used in surgery. Because microbial infection leads to complications, we developed antimicrobial PP suture by plasma-induced graft polymerization of acrylic acid followed by chitosan binding on the remaining carboxyl groups. Mechanical properties and surface morphologies were analyzed on these sutures. Tetracycline hydrochloride (TC) or nanosilver (NS) was then immobilized to PP. The resulting PP sutures evidenced drug release properties and antimicrobial activity in vitro. PP implanted in vivo for 30 days in the muscle of rats showed the absence of adverse effects and a tissue organization. This new polypropylene suture with suitable antimicrobial features appears to be a promising macromolecular material for clinical and cosmetic applications.

Eudragit S-100 entrapped chitosan microspheres of valdecoxib for colon cancer.

COX-2 inhibitors have demonstrated beneficial effects in colorectal cancer. The purpose of this study was to prepare and evaluate the colon specific microspheres of COX-2 inhibitors using valdecoxib as a model drug. Mucoadhesive core microspheres were prepared using chitosan as polymer and entrapped within Eudragit S 100 for colon targeting. FTIR spectrum of selected, coated microspheres showed peaks of valdecoxib at 3377, 3250, 1334 and 1155 cm(-1). XRD showed amorphous character and DSC showed depressed broad endotherm of valdecoxib at 169.07 degrees C, which may be attributed to dilution effect by the amorphous polymer. The coated microspheres were spherical with an average size of 90 mum. Storage of the microspheres at 40 degrees C/75% relative humidity for 6 months indicated no significant drug degradation. The coated microspheres did neither release the drug in acidic pH of stomach (pH 1.2) nor in small intestinal pH between 5 to 6.8, and the release started at pH 7.4, indicting perfect colonic delivery. The coated microspheres pretreated with phosphate buffer pH 7.4 for 30 min, when applied to mucosal surface of freshly excised goat colon, showed good mucoadhesion. The drug release at pH 7.4 and good mucoadhesive property of the microspheres make the system ideal for colonic delivery.

Agar-gelatin hybrid sponge-induced three-dimensional in vitro 'liver-like' HepG2 spheroids for the evaluation of drug cytotoxicity.

Agar-gelatin hybrid sponges were used as scaffolds to induce the formation of three-dimensional (3D) spheroids of HepG2 cells. Agar and gelatin in 2:1 ratio were used to make films and sponges. The cell adhesive properties of the films were evaluated by the attachment kinetics. The growth kinetics of HepG2 cells was studied using MTT assay and morphology of the 3D spheroids was observed through inverted optical microscopy. The liver cell-specific functions of the 3D spheroids were evaluated in terms of albumin secretion and urea synthesis. Paracetamol was used as a model drug to investigate the use of these 3D spheroids in the preliminary cytotoxicity evaluation of drugs. The results showed that the agar-gelatin hybrid sponges induced the formation of 3D HepG2 spheroids with significant liver-specific functions. These spheroids exhibited higher amounts of albumin and urea synthesis than the control monolayer culture. These 3D spheroids were found to be more sensitive to the drug (TCIC(50) value of 4.6 mM) than the control monolayer (TCIC(50) value of 6.2 mM). The study shows that agar-gelatin-induced HepG2 3D spheroids can be used for the preliminary evaluation of the toxicity of drugs and chemicals.

Formulation, characterization and evaluation of rotavirus encapsulated PLA and PLGA particles for oral vaccination.

Polylactide (PLA) and polylactide-co-glycolide (PLGA) particles entrapping rotavirus (strain SA11) were formulated using a solvent evaporation technique. To minimize denaturation of viral antigen during the emulsification process, serum albumin was used as a stabilizer. Use of NaHCO(3) and sucrose during the primary emulsification step resulted in uniform stabilized particles entrapping rotavirus. Sonication during the primary emulsion and homogenization during the secondary emulsion process resulted in particles of sizes 2-8 microm, whereas nanoparticles were formed when sonication was used during both primary and secondary emulsion processes. Scanning electron and atomic force microscopy showed uniform pores and roughness throughout the polymer particle surface. Single dose oral immunization with 20 microg of antigen entrapped in PLA particles elicited improved and long-lasting IgA and IgG antibody titer in comparison to the soluble antigen. The study shows results illustrating the usefulness of polymeric microparticles as a potential oral delivery system for rotavirus vaccine.