Organ-on-a-chip (OoC) devices simulate human organs within a microenvironment, potentially surpassing traditional preclinical methods and paving the way for innovative treatments. A thorough understanding of the current state of OoC design enables the development of more precise and relevant models that replicate not only the structure of organs but also their intricate cellular interactions and responses to external stimuli. This knowledge facilitates the optimization of biomimetic materials and allows for the real-time simulation of physiological microenvironments. By keeping abreast of new microfabrication techniques, we can explore opportunities to create customized and highly functional OoCs. Objective: To provide a comprehensive overview of microphysiological platform designs. Methods: This systematic review was registered in PROSPERO under the number CRD42022352569. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The eligibility criteria included studies utilizing human tissue, either primary or secondary lineage cells. Results: A total of 9.790 papers were retrieved from the Scopus, Embase, IEEE and Web of Science databases. After removing duplicates and applying a 10-year publication filter, 3.150 articles were screened by title and Full-text analyses were then performed. Eighteen studies met the eligibility criteria and were included in this systematic review. In this review, we examine the principles of OoC design, focusing on structure, dimensions, cell culturing options and manufacturing techniques. We also examine recent advances and future prospects in the field. Conclusions: Microphysiological devices in health research can facilitate drug discovery and improve our understanding of human physiology. They contribute to more ethical research by reducing the number of animals used in experiments.

Biomaterials interact with biological systems, influencing their responses. Different types of polymers—both natural and synthetic—are widely used in biomedical engineering, among a plethora of healthcare applications, to promote tissue regeneration. The natural rubber latex extracted from Hevea brasiliensis is a biopolymer that whose biocompatibility makes it a valuable study object. Its great regenerative properties are largely associated with the fraction FrHB1, which has demonstrated angiogenic and wound-healing potential by inducing blood vessel formation, collagen synthesis, and fibroblast migration—crucial factors for tissue repair. This study aimed to develop scalable methods for extracting and purifying the F1 protein fraction from industrialized natural latex for biomedical applications. We tested two types of industrial latex, bi-centrifuged and pre-vulcanized latex as well as 60% centrifuged natural latex to determine the most effective composition used in subsequent extractions and fractionation steps. Then, we isolated FrHB1 from the pre-vulcanized latex using selective precipitation, ultrafiltration, and affinity chromatography. The yield of the first batch of this serum was 40.62% with protein concentration of 1.52 ± 0.06 mg/mL. The second batch had a yield of 49.74%; however, due to results lying outside the analytical curve, its protein concentration could not be calculated. The yield of the third batch was 57.19%, and its protein concentration was 1.8477 ± 0.033 mg/mL. This approach facilitates large-scale therapeutic applications utilizing a commercially viable and accessible resource. Moreover, these findings highlight industrialized natural latex as a sustainable source of bioactive molecules, contributing to advancements in regenerative medicine and tissue engineering.

This study proposes an innovative mathematical model for assessing microcirculation in patients with diabetic ulcers, using the ankle–brachial index (ABI). The methodology combines Bond Graph (BG) modeling and Particle Swarm Optimization (PSO), enabling a detailed analysis of hemodynamic patterns in a pilot sample of three patients. The results revealed a correlation between ulcer size and reduced ABI values, suggesting that deficits in microcirculation directly impact the severity of lesions. Furthermore, despite variations in ABI values and arterial pressures, all patients exhibited high capillary resistance, indicating difficulties in microcirculatory blood flow. The PSO-optimized parameters for the capillary equivalent circuit were found to be $R_1=89.784\Omega$, $R_2=426.55\Omega$, $L=27.506\mathrm{H}$, and $C=0.00040675\mathrm{F}$, which confirms the presence of high vascular resistance and reduced compliance in the microvascular system of patients with diabetic foot ulcers. This quantitative analysis, made possible through mathematical modeling, is crucial for detecting subtle changes in microcirculatory dynamics, which may not be easily identified through conventional pressure measurements alone. The increased capillary resistance observed may serve as a key indicator of vascular impairment, potentially guiding early intervention strategies and optimizing diabetic ulcer treatment. We acknowledge that the sample size of three patients represents a limitation of the study, but this number was intentionally chosen to allow for a detailed and controlled analysis of the variables involved. Although the findings are promising, additional experimental validations are necessary to confirm the clinical applicability of the model in a larger patient sample, thus solidifying its relevance in clinical practice.

OBJETIVO: Analisar a cobertura vacinal geral dos imunobiológicos oferecidos pelo Programa Nacional de Imunizações (PNI) antes (2018-2019) e durante a pandemia da COVID-19 (2020-2021) no território brasileiro, por região e capital. METODOLOGIA: Foi realizado um estudo transversal, com dados secundários do PNI via Departamento de Informática do Sistema Único de Saúde (DATASUS). Os dados foram tabulados e submetidos a testes estatísticos, incluindo o teste de Shapiro-Wilk para verificar a normalidade e os testes de correlação de Pearson e Spearman. RESULTADOS: Foram aplicadas 407.570.811 doses de imunobiológicos no Brasil, a cobertura vacinal média geral do período (2018-2021) foi de 69,4%, exibindo tendência decrescente acentuada, que variou de 75,2% no período pré-pandêmico e 63,7% na pandemia. CONCLUSÃO: Durante a pandemia houve decréscimo da vacinação nacional em relação ao período anterior à mesma, com destaque das regiões Norte e Nordeste. Dessa forma, a pandemia pode ter contribuído para redução das imunizações.