Hydrogel Bioinks of Alginate and Curcumin-Loaded Cellulose Ester-Based Particles for the Biofabrication of Drug-Releasing Living Tissue Analogs.

3D bioprinting is a versatile technique that allows the fabrication of living tissue analogs through the layer-by-layer deposition of cell-laden biomaterials, viz. bioinks. In this work, composite alginate hydrogel-based bioinks reinforced with curcumin-loaded particles of cellulose esters (CEpCUR) and laden with human keratinocytes (HaCaT) are developed. The addition of the CEpCUR particles, with sizes of 740 ± 147 nm, improves the rheological properties of the inks, increasing their shear stress and viscosity, while preserving the recovery rate and the mechanical and viscoelastic properties of the resulting fully cross-linked hydrogels. Moreover, the presence of these particles reduces the degradation rate of the hydrogels from 26.3 ± 0.8% (ALG) to 18.7 ± 1.3% (ALG:CEpCUR_10%) after 3 days in the culture medium. The 3D structures printed with the ALG:CEpCUR inks reveal increased printing definition and the ability to release curcumin (with nearly 70% of cumulative release after 24 h in PBS). After being laden with HaCaT cells (1.2 × 106 cells mL-1), the ALG:CEpCUR bioinks can be successfully 3D bioprinted, and the obtained living constructs show good dimensional stability and high cell viabilities at 7 days post-bioprinting (nearly 90%), confirming their great potential for application in fields like wound healing.

Nanofibrillated cellulose/gellan gum hydrogel-based bioinks for 3D bioprinting of skin cells.

The development of suitable bioinks is an important research topic in the field of three-dimensional (3D) bioprinting. Herein, novel hydrogel-based bioinks composed of nanofibrillated cellulose (NFC) and gellan gum (GG) in different NFC/GG mass proportions (90:10, 80:20, 70:30, and 60:40) were developed and characterized. The increase in the content of GG, as well as its combination with NFC, enhanced their rheological properties, increasing both storage (G') and loss (G") moduli and the G' recovery capacity of the hydrogels (from 70.05 ± 3.06 % (90:10) to 82.63 ± 1.21 % (60:40)), as well as their mechanical properties, increasing the compressive stiffness and stress from 114.02 ± 10.93 Pa (90:10) to 337.16 ± 34.03 Pa (60:40) and from 18.27 ± 1.32 kPa (90:10) to 47.17 ± 3.59 kPa (60:40), respectively. The hydrogels were non-cytotoxic against human keratinocyte cells (HaCaT), with cell viabilities above 70 % for up to 72 h. The hydrogel 60:40 was loaded with HaCaT cells (3 × 106 cells mL-1) and bioprinted. The cell viability was maintained elevated until day 7 (90 ± 3 %) after bioprinting. These results highlight that the combination of these two biopolymers was a good strategy for the development of novel hydrogel-based bioinks for extrusion 3D bioprinting applications.

Alginate-Lysozyme Nanofibers Hydrogels with Improved Rheological Behavior, Printability and Biological Properties for 3D Bioprinting Applications.

In this study, alginate nanocomposite hydrogel bioinks reinforced with lysozyme nanofibers (LNFs) were developed. Alginate-LNF (A-LNF) suspensions with different LNF contents (1, 5 and 10 wt.%) were prepared and pre-crosslinked with 0.5% (w/v) CaCl2 to formulate A-LNF inks. These inks exhibit proper shear-thinning behavior and good recovery properties (~90%), with the pre-crosslinking step playing a crucial role. A-LNF fully crosslinked hydrogels (with 2% (w/v) CaCl2) that mimic 3D printing scaffolds were prepared, and it was observed that the addition of LNFs improved several properties of the hydrogels, such as the morphology, swelling and degradation profiles, and mechanical properties. All formulations are also noncytotoxic towards HaCaT cells. The printing parameters and 3D scaffold model were then optimized, with A-LNF inks showing improved printability. Selected A-LNF inks (A-LNF0 and A-LNF5) were loaded with HaCaT cells (cell density 2 × 106 cells mL-1), and the cell viability within the bioprinted scaffolds was evaluated for 1, 3 and 7 days, with scaffolds printed with the A-LNF5 bioink showing the highest values for 7 days (87.99 ± 1.28%). Hence, A-LNF bioinks exhibited improved rheological performance, printability and biological properties representing a good strategy to overcome the main limitations of alginate-based bioinks.

A Guide to Polysaccharide-Based Hydrogel Bioinks for 3D Bioprinting Applications.

Three-dimensional (3D) bioprinting is an innovative technology in the biomedical field, allowing the fabrication of living constructs through an approach of layer-by-layer deposition of cell-laden inks, the so-called bioinks. An ideal bioink should possess proper mechanical, rheological, chemical, and biological characteristics to ensure high cell viability and the production of tissue constructs with dimensional stability and shape fidelity. Among the several types of bioinks, hydrogels are extremely appealing as they have many similarities with the extracellular matrix, providing a highly hydrated environment for cell proliferation and tunability in terms of mechanical and rheological properties. Hydrogels derived from natural polymers, and polysaccharides, in particular, are an excellent platform to mimic the extracellular matrix, given their low cytotoxicity, high hydrophilicity, and diversity of structures. In fact, polysaccharide-based hydrogels are trendy materials for 3D bioprinting since they are abundant and combine adequate physicochemical and biomimetic features for the development of novel bioinks. Thus, this review portrays the most relevant advances in polysaccharide-based hydrogel bioinks for 3D bioprinting, focusing on the last five years, with emphasis on their properties, advantages, and limitations, considering polysaccharide families classified according to their source, namely from seaweed, higher plants, microbial, and animal (particularly crustaceans) origin.

Nanomedicines for the Delivery of Antimicrobial Peptides (AMPs).

Microbial infections are still among the major public health concerns since several yeasts and fungi, and other pathogenic microorganisms, are responsible for continuous growth of infections and drug resistance against bacteria. Antimicrobial resistance rate is fostering the need to develop new strategies against drug-resistant superbugs. Antimicrobial peptides (AMPs) are small peptide-based molecules of 5-100 amino acids in length, with potent and broad-spectrum antimicrobial properties. They are part of the innate immune system, which can represent a minimal risk of resistance development. These characteristics contribute to the description of these molecules as promising new molecules in the development of new antimicrobial drugs. However, efforts in developing new medicines have not resulted in any decrease of drug resistance yet. Thus, a technological approach on improving existing drugs is gaining special interest. Nanomedicine provides easy access to innovative carriers, which ultimately enable the design and development of targeted delivery systems of the most efficient drugs with increased efficacy and reduced toxicity. Based on performance, successful experiments, and considerable market prospects, nanotechnology will undoubtedly lead a breakthrough in biomedical field also for infectious diseases, as there are several nanotechnological approaches that exhibit important roles in restoring antibiotic activity against resistant bacteria.

New Nanotechnologies for the Treatment and Repair of Skin Burns Infections.

Burn wounds are highly debilitating injuries, with significant morbidity and mortality rates worldwide. In association with the damage of the skin integrity, the risk of infection is increased, posing an obstacle to healing and potentially leading to sepsis. Another limitation against healing is associated with antibiotic resistance mainly due to the use of systemic antibiotics for the treatment of localized infections. Nanotechnology has been successful in finding strategies to incorporate antibiotics in nanoparticles for the treatment of local wounds, thereby avoiding the systemic exposure to the drug. This review focuses on the most recent advances on the use of nanoparticles in wound dressing formulations and in tissue engineering for the treatment of burn wound infections.

Impact of a provider training program on the treatment of children with autism spectrum disorder at psychosocial care units in Brazil

Objective: To develop, implement, and verify the impact of a training program for health care providers working with children with autism spectrum disorder (ASD) in psychosocial care centers for children and adolescents (Centro de Atenção Psicossocial à Infância e à Adolescência - CAPSi) in São Paulo, Brazil. Methods: This quasi-experimental study was conducted with 14 professionals from four CAPSi units. The training program consisted of six phases: 1) pre-intervention observation; 2) meeting with staff to assess the main needs of the training program; 3) developing materials for training and evaluation; 4) meetings to discuss program implementation; 5) a final meeting for case discussion and evaluation; and 6) distance supervision. Three measures were used to evaluate the training program: i) the Knowledge, Attitudes, and Practices (KAP) questionnaire; ii) videos containing questions designed to assess program comprehension; and iii) a satisfaction survey. Results: Thirteen videos were produced to as visual aids for use during the training program, and a further 26 videos were developed to evaluate it. The program was well evaluated by the participants. The video responses and KAP questionnaire scores suggest that staff knowledge and attitudes improved after training. Conclusion: The positive findings of this study suggest that the tested training program is feasible for use with multidisciplinary teams working in the CAPSi environment.

Impact of a provider training program on the treatment of children with autism spectrum disorder at psychosocial care units in Brazil.

OBJECTIVE: To develop, implement, and verify the impact of a training program for health care providers working with children with autism spectrum disorder (ASD) in psychosocial care centers for children and adolescents (Centro de Atenção Psicossocial à Infância e à Adolescência - CAPSi) in São Paulo, Brazil. METHODS: This quasi-experimental study was conducted with 14 professionals from four CAPSi units. The training program consisted of six phases: 1) pre-intervention observation; 2) meeting with staff to assess the main needs of the training program; 3) developing materials for training and evaluation; 4) meetings to discuss program implementation; 5) a final meeting for case discussion and evaluation; and 6) distance supervision. Three measures were used to evaluate the training program: i) the Knowledge, Attitudes, and Practices (KAP) questionnaire; ii) videos containing questions designed to assess program comprehension; and iii) a satisfaction survey. RESULTS: Thirteen videos were produced to as visual aids for use during the training program, and a further 26 videos were developed to evaluate it. The program was well evaluated by the participants. The video responses and KAP questionnaire scores suggest that staff knowledge and attitudes improved after training. CONCLUSION: The positive findings of this study suggest that the tested training program is feasible for use with multidisciplinary teams working in the CAPSi environment.

Segmentos anátomo-cirúrgicos arteriais do rim de cutia (Dasyprocta prymnolopha) / Anatomical-surgical arterial segments of the kidney in agouti (Dasyprocta prymnolopha)

Foram estudados 20 pares de rins de cutias (Dasyprocta prymnolopha Wagler, 1831), com o objetivo de descrever os segmentos anátomo-cirúrgicos arteriais. As artérias renais foram injetadas com solução de Vinilite corada, e os rins foram submetidos à corrosão ácida para a obtenção dos moldes vasculares. Observou-se que as artérias renais da cutia, sempre únicas, dividiram-se em artéria setorial ventral e artéria setorial dorsal, caracterizando dois setores renais separados por plano avascular. As artérias setoriais penetraram no hilo renal (100 por cento dos casos). Estes vasos deram origem aos ramos segmentares responsáveis pela irrigação de territórios independentes em cada setor, os segmentos arteriais renais. No rim direito foram observados 3 (60 por cento), 4 (35 por cento) e 5 segmentos (5 por cento) no setor arterial ventral e 3 (30 por cento), 4 (45 por cento), 5 (20 por cento) e 6 (5 por cento) segmentos no setor dorsal e, à esquerda, 2(10 por cento), 3 (55 por cento) e 4 (35 por cento) segmentos no setor ventral e 3 (25 por cento), 4 (50 por cento) e 5 (25 por cento) no dorsal. Com base na distribuição arterial nos rins de cutia, observaram-se setores e segmentos arteriais independentes, sendo possível, desta forma, a realização de setoriectomia e segmentectomia nesta espécie.

Twenty pairs of agouti (Dasyprocta prymnolopha Wagler, 1831) kidneys were studied to describe the arterial anatomical-surgical segments. The renal arteries were injected with stained acetate vinyl, followed by procedures of acid corrosion in order to obtain vascular casts. It was found that the renal artery is always single and bifurcated into ventral and dorsal sectorial arteries. The sectorial arteries reached the kidneys (100 percent of the cases) through the hilus. These vessels gave origin to segmental branches responsible for kidney irrigation. At the right kidney, the ventral sectorial arteries gave origin to 3 (60 percent of the cases), 4 (35 percent) and 5 (5 percent) segmental branches; the dorsal sectorial arteries gave origin to 3 (30 percent), 4 (45 percent), 5 (20 percent) and 6 (5 percent) segmental arteries separated by a vascular sector. At the left kidney, the ventral sectorial arteries originated 2 (10 percent), 3 (55 percent) or 4 (35 percent) segmental branches; the dorsal sectorial arteries gave origin to 3 (25 percent), 4 (50 percent) and 5 (25 percent) segmental branches. Based on the arterial distribution of agouti kidneys, independent sections and arterial segments were found, so that it is possible to accomplish partial kidney resection surgery.

Evaluation of serum- and animal protein-free media for the production of infectious bronchitis virus (M41) strain in a continuous cell line.

Infectious bronchitis virus (IBV) is produced in vitro using specific pathogen free chicken embryos, primary chicken kidney cells (CKC) and/or tracheal organ culture (TOC). Regulatory authorities in Europe (EMEA) and in the United States (FDA) have encouraged biological manufactures to reduce or eliminate the use of live animals and/or products of animal origin in biological manufacturing processes. In this paper, a stable chicken embryo-related (CER) cell line was adapted and maintained in serum free (SF) or animal protein free (APF) medium after a direct switch of the medium. The most suitable media were Ex Cell 520 and Ex Cell 302. CER monolayers adapted to SF or APF were infected with IBV (M41 strain) in agitated suspended culture and the IBV titre obtained 48 h post infection was 2.8 x 104 PFU/ml in both cases. Thus, propagation of CER cells and culture of IBV can be performed without the use of animal serum or animal protein.