Nanoskin® Subcutaneous Implant in Guinea Pigs.

PURPOSE: To evaluate the suitability of Nanoskin, a biomaterial derived from bacterial cellulose, as an alternate material for repairing the posterior lamellae of the eyelids. METHODS: Forty guinea pigs received a fragment of Nanoskin subcutaneously in the dorsal region. The animals received Nanoskin (group 1) or Nanoskin coated with a gelatin layer (group 2). The animals were observed daily for over 7, 30, 90, or 180 days with the subcutaneous implants in place. The animals were euthanized at a designated time and the Nanoskin was removed for histologic, morphometric, and transmission electron microscopy evaluation. RESULTS: The results were similar for both groups. The subcutaneously implanted Nanoskin resulted in good tissue integration, induced mild inflammation, and was surrounded by a delicate pseudocapsule. CONCLUSION: The good tissue integration of Nanoskin in study indicates that it may be a potential material for application as a substitute of posterior eyelid lamellar tissue. Further clinical studies are required to confirm the preliminary outcomes of this experimental study.

Novel electrospun nanotholits/PHB scaffolds for bone tissue regeneration.

Nanotholits is an osteoinductor or be, stimulates the bone regeneration, enabling bigger migration of the cells for formation of the bone tissue regeneration mainly because nanotholits are rich in minerals considered essential to the bone mineralization process on a protein matrix (otolin) as hydroxiapatite. In order to improve its biodegrability and bioresorption in new platforms for tissue engineering, it was electrospun PHB/nanotholits from aqueous solutions of this polymer at concentrations of nanotholits 1% (w/v) and compared morphological and thermal properties with PHB/nanotholits casting films. Electrospun PHB/nanotholits mats presents more symmetric nanopore structure than casting films mats observed by SEM images mainly because the orientation of pores along the longitudinal direction of the electrospun fibers. Nanotholits influences in PHB electrospun/casting was analyzed using transmission infrared spectroscopy (FTIR). TGA showed similar thermal properties but DSC showed distinct thermal properties and crystallinity process of the developed bionanocomposite mainly because of different processing.

Cellulose biomembrane versus collagenase dressing for the treatment of chronic venous ulcers: a randomized, controlled clinical trial.

Cellulose biomembranes may be used for difficult-to-treat ulcers. To assess the efficacy and safety of cellulose biomembranes compared to a collagenase dressing for the treatment of chronic venous ulcers. A randomized, controlled clinical trial was performed using two groups: one treated with collagenase dressing and the other with cellulose biomembrane over a 90-day (T90) period. Both groups received compression therapy. The primary outcome was reduction in ulcer area at T90. Secondary outcomes were healing status, decrease in devitalized tissue and exudate, vascular fraction, change in quality of life, and safety. We randomized 46 participants with 73 venous ulcers (21 with 36 ulcers in the collagenase group and 25 with 37 ulcers in the biomembrane group). A decrease in ulcer area occurred at T90 in both groups, but the difference was not significant. Complete healing before T90 occurred for seven ulcers in the collagenase group and 12 ulcers in the biomembrane group, without significant difference. However, the biomembrane promoted increased precocious healing (p = 0.02). Improved bed vitality and quality of life was observed as a function of time (p < 0.01), but this was not significant between the groups. Immunohistochemical analysis of CD34 showed an increase in vascular fraction in both groups (p < 0.01), with a higher level in the biomembrane group (p < 0.05). No adverse events were considered related to the products. Cellulose biomembranes, in combination with compressive therapy, are effective and safe for the treatment of venous ulcers and provide results similar to those with collagenase treatment.

Nanoskin® to treat full thickness skin wounds.

This experimental study evaluated 40 guinea pigs that received Nanoskin®. A full thickness skin rectangle measuring 2x4 cm was removed from the median dorsal region and the wound was covered by a 2X2 cm fragment of uncoated Nanoskin® graft (uncoated group) or Nanoskin® coated with gelatin (coated group) and sutured in the caudal region and a 2x2 cm fragment of autologous skin sutured in the cranial aspect of the surgical wound served a control. The animals were examined daily by ectoscopy and euthanized at 7, 30, 90 and 180 days postoperatively. Immediately after euthanasia, the operated area was shaved, documented with photos and removed, and prepared for morphological, morphometric and ultrastructural exam. It was found that the full thickness skin wound healed in a centripetal pattern. The healing process was similar between groups, with a more pronounced inflammatory reaction initially that gradually decreased over time. The conclusion is that the uncoated Nanoskin® or Nanoskin® coated with gelatin is a good material to treat full thickness skin wound. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 724-732, 2019.

Surface physical chemistry properties in coated bacterial cellulose membranes with calcium phosphate.

Bacterial cellulose has become established as a new biomaterial, and it can be used for medical applications. In addition, it has called attention due to the increasing interest in tissue engineering materials for wound care. In this work, the bacterial cellulose fermentation process was modified by the addition of chondroitin sulfate to the culture medium before the inoculation of the bacteria. The biomimetic process with heterogeneous calcium phosphate precipitation of biological interest was studied for the guided regeneration purposes on bacterial cellulose. FTIR results showed the incorporation of the chondroitin sulfate in the bacterial cellulose, SEM images confirmed the deposition of the calcium phosphate on the bacterial cellulose surface, XPS analysis showed a selective chemical group influences which change calcium phosphate deposition, besides, the calcium phosphate phase with different Ca/P ratios on bacterial cellulose surface influences wettability. XTT results concluded that these materials did not affect significantly in the cell viability, being non-cytotoxic. Thus, it was produced one biomaterial with the surface charge changes for calcium phosphate deposition, besides different wettability which builds new membranes for Guided Tissue Regeneration.

Novel chemically modified bacterial cellulose nanocomposite as potential biomaterial for stem cell therapy applications.

Bacterial cellulose (BC) has become established as a remarkably versatile biomaterial and can be used in a wide variety of applied scientific applications, especially for medical devices. In this work, the bacterial cellulose fermentation process is modified by the addition of hyaluronic acid and gelatin (1% w/w) to the culture medium before the bacteria is inoculated. Hyaluronic acid and gelatin influence in bacterial cellulose was analyzed using Transmission Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adhesion and viability studies with human dental pulp stem cells using natural bacterial cellulose/hyaluronic acid as scaffolds for regenerative medicine are presented for the first time in this work. MTT viability assays show higher cell adhesion in bacterial cellulose/gelatin and bacterial cellulose/ hyaluronic acid scaffolds over time with differences due to fiber agglomeration in bacterial cellulose/gelatin. Confocal microscopy images showed that the cell were adhered and well distributed within the fibers in both types of scaffolds.

Human dental pulp stem cell behavior using natural nanotolith/bacterial cellulose scaffolds for regenerative medicine.

Adhesion and Viability study with human dental pulp stem cell using natural nanotolith/bacterial cellulose scaffolds for regenerative medicine are presented at first time in this work. Nanotolith, are osteoinductors, i.e., they stimulate bone regeneration, enabling higher cells migration for bone tissue regeneration formation. This is mainly because nanotoliths are rich minerals present in the internal ear of bony fish. In addition, are part of a system which acts as a depth sensor and balance, acting as a sound vibrations detector and considered essential for the bone mineralization process, as in hydroxiapatites. Nanotoliths influence in bacterial cellulose was analyzed using transmission infrared spectroscopy (FTIR). Results shows that fermentation process and nanotoliths agglomeration decrease initial human dental pulp stem cell adhesion however tested bionanocomposite behavior has cell viability increase over time.

Nanoskin: uso para reposição de volume na cavidade anoftálmica / Use of Nanoskin for volume replacement of the eye socket

RESUMO Objetivo: Avaliar a biocompatibilidade da Nanoskin para reposição de volume em cavidades enucleadas ou evisceradas de coelhos. Métodos: Estudo experimental, utilizando implantes de Nanoskin (Innovatecs®, São Carlos, Brasil), celulose bacteriana produzida pela bactéria Acetobacter xylinum tendo como substrato o chá-verde. Implantes de 10mm de diâmetro/5mm de espessura foram colocados em cavidades enucleadas (G1) ou evisceradas (G2) de 21 coelhos, avaliados clinicamente todos os dias, sacrificados aos 7, 30 e 90 dias após a cirurgia. O material foi removido e preparado para exame de microscopia óptica. Resultados: Sinais flogísticos discretos no pósoperatório imediato, não tendo sido evidenciados sinais infecciosos ou extrusão de nenhum implante. Houve aparente redução do volume ao longo do período experimental. Histologicamente ambos os grupos foram muito semelhantes, apresentando aos 7 dias células inflamatórias (predominantemente monócitos e neutrófilos), rede de fibrina e hemácias. A Nanoskin apresentava-se como pequenas esferas, de cor rósea, com pequenos espaços entre elas, permeados por escassas células inflamatórias. As células inflamatórias se modificaram ao longo de período experimental, sendo possível observar aos 30 dias células gigantes multinucleadas e fibroblastos maduros permeando o implante. Aos 90 dias, a estrutura do implante apresentava-se desorganizada, amorfa, com restos necróticos e com áreas ovoides, revestidas por fina membrana rósea, que pareciam se agrupar, vazias ou preenchidas por material acelular, róseo ou acinzentado. Conclusão: A Nanoskin provocou reação inflamatória que levou à reabsorção e redução do volume do implante. Novas formulações devem ser estudadas a fim de ter um produto que seja permanente para reparo da cavidade anoftálmica.

ABSTRACT Objective: The aim of this study was to evaluate the biocompatibility of Nanoskin for replacing volume in enucleated or eviscerated anophthalmic sockets of rabbits. Methods: An experimental study was carried out using enucleated or eviscerated rabbits, which received Nanoskin implants (Innovatecs®, São Carlos, Brazil), a cellulose produced by a bacteria (Acetobacter xylinum) using green tea as substrate. Implants of 10mm diameter/5mm of thickness were used placed in enucleated (G1) or eviscerated (G2) anophthalmic sockets of 21 rabbits.They were clinically examined daily, sacrificed at 7, 30 and 90 days after surgery and the material was removed and prepared for histological examination. Results: There were discrete signs of inflammation in the immediate postoperative period, with no evidence of infection or extrusion in any animal. However apparent reduction of volume during the trial period occurred. Histologically both groups were similar, with inflammatory cells (mainly monocytes and neutrophils), fibrin and hemaceas at 7 days postoperatively.The Nanoskin was presented as small pink spheres, with small gaps between them and permeated by few inflammatory cells. These cells have changed over the study, at 30 days multinucleated giant cells and mature fibroblasts that permeate the implant were observed. At 90 days, the structure of the implant was disorganized, amorphous, with necrotic debris and ovoid areas covered with thin pink membrane that seemed to cluster, empty or filled with no cellular pink or gray material. Conclusion: Nanoskin caused an inflammatory reaction leading to reabsorption and reduction of implant volume. New formulations should be studied in order to have a permanent product to repair the anophthalmic socket.