Christiane Bertachini Lombello

Electrospinning of Gelatin/Poly (Vinyl Pyrrolidone) Blends from Water/Acetic Acid Solutions

Electrospinning is a versatile and efficient technique for obtaining polymeric microfibers and nanofibers with great potential for applications in tissue engineering, biosensors, filtration, wound dressings, controlled drug release and enzyme immobilization. Electrospun fibers are obtained by applying an electric field in a polymer solution resulting in non-woven fibrous mats with high surface area relative to volume and high porosity. In this work, the electrospinning of gelatin/poly(vinyl pyrrolidone) (PVP) blends was investigated. The polymers were electrospun from solutions containing different concentrations of water and acetic acid. Solutions were characterized by measuring the pH, electrical conductivity, surface tension and viscosity. The influence of acetic acid concentration in solution properties and its influence in the spinnability were investigated. The resulting non-woven membranes were characterized by using scanning electron microscopy (SEM), thermogravimetric analysis (TG) and cytotoxicity.

Transplante autólogo de condrócitos: relato de três casos

Hyaline cartilage in the surface of synovial joints plays an important role in lowering stress and attrition in joints such as the knee. This tissue has no blood vessels, nerves, nor lymphatic drainage, which in part explains why articular cartilage has such poor capacity for healing. Chondral lesions reaching the subchondral bone (osteochondral lesions) do not heal and may progress to osteoarthritis as time passes. In young patients, treatment of such defects is challenging, especially in lesions larger than 4 cm. One option in young adults is the autologous chondrocyte implantation, capable of filling the defect with tissue similar to hyaline cartilage without violating the subchondral bone. Theoretically, it has biological and mechanical advantages over other surgical options. In this paper, we describe the experience with this procedure in a series of 3 cases at the Institute of Orthopedics and Traumatology, University of Sao Paulo.

Evaluation of cell interaction with polymeric biomaterials based on hyaluronic acid and chitosan

Tissue engineering involves the development of new materials or devices capable of specific interactions with biological tissues, searching the use of biocompatible materials as scaffolds for in vitro cell growth, and functional tissue development, that is subsequently implanted into patient. The aim of the current study was to evaluate the initial aspects of cell interaction with the polymeric biomaterials blends based on hyaluronic acid with chitosan. The hypothesis approach involves synthesis and analysis of swelling and thermal degradation (thermal gravimetric analysis) of the polymer blend; and Vero cell interaction with the biomaterial, through analysis of cytotoxicity, adhesion and cell morphology. The blend resulted in a biomaterial with a high swelling ratio that can allow nutrient distribution and absorption. The thermal gravimetric analysis results showed that the blend had two stages of degradation at temperatures very close to those observed for pure polymers, confirming that the physical mixing of hydrogels occurred, resulting in the presence of both hyaluronic acid and chitosan in the blend. The evaluation of indirect cytotoxicity showed that the blend was non cytotoxic for Vero cells, and the quantitative analysis performed with the MTT could verify a cell viability of 98%. The cells cultured on the blend showed adhesion, spreading and proliferation on this biomaterial, distinguished from the pattern of the control cells. These results showed that the blends produced from hyaluronic acid and chitosan hydrogels are promising for applications in tissue engineering, aiming at future cartilaginous tissue.Graphical Abstract

Cyclodextrin-Based Delivery Systems for Arthritic Diseases: From Development to Experimental Therapeutics

Arthritics diseases, such as rheumatoid arthritis and osteoarthritis are chronic inflammatory and one of the most prevalent health conditions that cause disability (pain and functional limitation of joints). Despite the research advances, the treatment of those pathological conditions remains ineffective, since the pharmacological therapy is palliative, reducing only the symptoms and, in some cases, the chronic progression of the disease. In this context, the development of new formulations for controlled release would be interesting for reducing the number of injections and would also increase the patient compliance. In this article, we present a review of the cyclodextrin (CD)-based delivery systems focusing from conventional guest-host inclusion complexes and CD-polysulphates, until supramolecular architectures such as drug-CD-polymers conjugates, pseudorotaxanes, hydrogels as well as double-carrier systems and other systems. In particular, this article focuses the main CD-based delivery systems described in the literature emphasizing their possible administration by intra-articular route on the treatment of arthritic diseases, concentrating on their development and also performance as in vivo experimental therapeutic systems.

Biocompatible and Antibacterial Nitric Oxide-Releasing Pluronic F-127/Chitosan Hydrogel for Topical Applications

Nitric oxide (NO) is involved in physiological processes, including vasodilatation, wound healing and antibacterial activities. As NO is a free radical, designing drugs to generate therapeutic amounts of NO in controlled spatial and time manners is still a challenge. In this study, the NO donor S-nitrosoglutathione (GSNO) was incorporated into the thermoresponsive Pluronic F-127 (PL)-chitosan (CS) hydrogel, with an easy and economically feasible methodology. CS is a polysaccharide with known antimicrobial properties. Scanning electron microscopy, rheology and differential scanning calorimetry techniques were used for hydrogel characterization. The results demonstrated that the hydrogel has a smooth surface, thermoresponsive behavior and good mechanical stability. The kinetics of NO release and GSNO diffusion from GSNO-containing PL/CS hydrogel demonstrated a sustained NO/GSNO release, in concentrations suitable for biomedical applications. The GSNO-PL/CS hydrogel demonstrated a concentration-dependent toxicity to Vero cells, and antimicrobial activity to Pseudomonas aeruginosa (minimum inhibitory concentration and minimum bactericidal concentration values of 0.5 µg·mL−1 of hydrogel, which corresponds to 1 mmol·L−1 of GSNO). Interestingly, the concentration range in which the NO-releasing hydrogel demonstrated an antibacterial effect was not found to be toxic to the Vero mammalian cell. Thus, the GSNO-PL/CS hydrogel is a suitable biomaterial for topical NO delivery applications.

Cell interactions and cytotoxic studies of cellulose nanofibers from Curauá natural fibers

Cellulose nanofibers (CNF) were isolated from Curauá fibers (Ananas erectifolius L. B. Smith) through a mechanical grinder preceded by mild chemical treatment. Morphology and surface characteristics of the fibers were followed until it reaches the nanoscale as long and flexible nanofibers. In aqueous suspensions, SAXS techniques revealed that such nanofibers present a twisted ribbon structure while rheological measurements demonstrate its high viscosity and a thixotropic behavior. These characteristics suggests the potential application of CNF in biomedical field, which, in turn, stimulates the toxicological studies of such materials. The obtained materials do not show any sign of cytotoxicity by direct or indirect assays for cell viability and cell morphology using Vero cells. Moreover, during the adhesion test, the cells demonstrated higher affinity to the CNF surface. It can be related to its surface properties and its obtaining conditions, which did not use any hazardous chemicals.

Hidrogéis a base de ácido hialurônico e quitosana para engenharia de tecido cartilaginoso

A Engenharia de Tecidos envolve o desenvolvimento de novos materiais ou dispositivos capazes de interacoes especificas com os tecidos biologicos, buscando a utilizacao de materiais biocompativeis que devem servir como arcabouco para o crescimento de celulas in vitro, organizando e desenvolvendo o tecido que posteriormente sera implantado no paciente. Uma variedade de arcaboucos como hidrogeis polimericos, sinteticos e naturais, tem sido investigados para a expansao de condrocitos in vitro, visando o reparo da cartilagem lesionada. Um hidrogel de interesse particular na regeneracao de cartilagem e o acido hialuronico (AH). Trata-se de um biopolimero atraente para a fabricacao de arcaboucos artificiais para Engenharia de Tecidos por ser biocompativel e biodegradavel. A biocompatibilidade do AH deve-se ao fato de estar presente na matriz extracelular nativa, deste modo, cria-se um ambiente propicio que facilita a adesao, proliferacao e diferenciacao celular, alem da existencia de sinalizacao celular especifica, o que contribui para a regeneracao do tecido. O uso de hidrogel composto de acido hialuronico e quitosana (QUI) tambem tem sido investigado em aplicacoes de Engenharia de Tecidos de cartilagem, com resultados promissores. Baseando-se nestas informacoes, o objetivo este trabalho foi investigar as alternativas disponiveis para regeneracao tecidual da cartilagem e conhecer mais detalhadamente as relacoes entre celulas e biomateriais.

HA/TCP Scaffolds Coated by PLA and Gelatin: Preliminary In Vitro Evaluation

The importance of this work is development of two methods to try to improve the bone tissue regeneration. The surface of scaffold was modified in order to favor cell interaction, through adhesion and proliferation. PLA and gelatin were used. PLA has shown in literature good results in bone tissue engineering. The gelatin is used as coating in cell culture plates to improve cell attachment for a variety of cell types, including osteoblast. Hydroxyapatite (HA) and tricalcium phosphate (TCP) were used due to its known properties in tissue engineering. It was used the polymer foam replication technique to produce the scaffolds. For characterization were used: scanning electron microscopy (SEM), optical microscopy (OP), stereoscopy, transmission electron microscopy (TEM), X-ray microtomography (Micro-CT), X-ray diffraction (XRD) and X-ray fluorescence (XRF). The scaffolds showed morphology with adequate porosity for tissue engineering and the in vitro test showed evidence of not being cytotoxic.

AUTOLOGOUS CHONDROCYTE TRANSPLANTATION-SERIES OF 3 CASES

Hyaline cartilage covers joint surfaces and plays an important role in reducing friction and mechanical loading on synovial joints such as the knee. This tissue is not supplied with blood vessels, nerves or lymphatic circulation, which may be one of the reasons why joint cartilage has such poor capacity for healing. Chondral lesions that reach the subchondral bone (osteochondral lesions) do not heal and may progress to arthrosis with the passage of time. In young patients, treatment of chondral defects of the knee is still a challenge, especially in lesions larger than 4 cm. One option for treating these patients is autologous chondrocyte transplantation/implantation. Because this treatment does not violate the subchondral bone and repairs the defect with tissue similar to hyaline cartilage, it has the theoretical advantage of being more biological, and mechanically superior, compared with other techniques. In this paper, we describe our experience with autologous chondrocyte transplantation/implantation at the Institute of Orthopedics and Traumatology, Hospital das Clínicas, University of Sâo Paulo, through a report on three cases.