International Journal of Advances in Medical Biotechnology - IJAMB

Special Edition Submission: Dr. Jorge Vicente Lopes da Silva

2024-12-18T16:16:07-02:00

There are texts that are easy to write and then there are others that have such an emotional significance that are much harder. I was invited to write about Jorge Vicente Lopes da Silva, a Brazilian researcher that had and continues to have a worldwide impact in the scientific, academic and industrial domain. He had a significant scientific contribution worldwide, but his greatest impact was the friendships that he created with everyone that had the opportunity of meeting him.

O Development of gels composed of pectin/microcellulose from mango and peg for biotechnological applications

2023-10-09T16:51:01-03:00

Com base no conceito de economia circular, resíduos de fontes vegetais, entre eles manga, são reaproveitados e podem ser extraídas algumas biomoléculas como pectina e celulose para serem utilizadas em aplicações biotecnológicas, também para a indústria cosmética, até mesmo como biomateriais. Neste contexto, foi realizada a caracterização térmica, morfológica e reológica de biopolímeros puros e misturas em gel para analisar seu potencial para produzir membranas, scaffolds ou estruturas bioimpressas. A análise FTIR foi realizada demonstrando comportamentos e agrupamentos semelhantes entre os materiais estudados. O índice de cristalinidade e áreas amorfas obtidas por ensaio de XRD. Além disso, outra análise realizada foi referente ao grau de polimerização de acordo com a viscosidade das amostras demonstrando o tempo de escoamento dos polímeros. Depois de caracterizar os polímeros, formulações de géis combinados de pectina de manga, microcelulose de manga e microcelulose vegetal com fontes de madeira foram produzidas através de calorimetria, microscópio eletrônico de varredura (MEV) e análises reológicas. O PEG foi adicionado com a finalidade de melhorar as propriedades reológicas e a compatibilidade entre as fases destes géis. Concluímos através da caracterização destes materiais a viabilidade na produção de estruturas para aplicações biotecnológicas como scaffolds nas áreas médicas entre outras.

Encapsulation and controlled release of 1,4-naphthoquinone in PDLA nanoparticles: design, biological efficacy, and cancer targeting

2024-11-06T15:08:13-02:00

Drug release can be controlled by encapsulating active compounds in polymeric vehicles. Using nanotechnology, pharmaceutical drug delivery systems can be controlled and precise. The aim of this work is to obtain and characterize biocompatible micro and nanoparticulate systems based on a poly(D-lactic acid) matrix (PDLA) to study the controlled release of 1,4-naphthoquinone, which has reported anticancer activity. Scanning electron microscopy revealed spherical particles with an average size of 347 nm and 86% in the nanometer range. The encapsulation efficiency was 98.3%, as assessed by UV-visible spectroscopy. The hydrolytic degradation over 11 weeks showed controlled release of naphthoquinone at different pH conditions: 20.98% in alkaline, 19.69% in physiological, 18.83% in strongly acidic, and 16.70% in slightly acidic conditions. The enhanced release at alkaline pH suggests potential anticancer activity in colorectal cancer, benefiting treatment by releasing the drug to the affected area. Molecular docking studies on COX-2 confirmed these results, showing 1,4-naphthoquinone interacts with key amino acids (ALA202, THR206, HIS207) in the active site, modifying the prostaglandin chain which is crucial for the enzyme's function. The results show that this system has a high potentiality for use for pharmacological applications in colorectal cancer, as 1,4-naphthoquinone exhibits electronic properties.

Influence of viscosity and velocity of administration on the performance of hyaluronic acid as a vehicle for bioprinting and injectable cell therapy: a computer simulation approach and in vitro validation

2024-12-04T00:03:13-02:00

Background: Hyaluronic acid (HA) is a natural polymer widely used as a vehicle in injectable cell therapy for the treatment of arthropathies. Objective: To estimate, through computational simulations and in vitro validation, the influence of HA’s physicochemical properties and administration speed on the shear stress generated in the syringe/needle system, as well as the associated risk to cell viability during administration. Methods: The influence of viscosity was evaluated by considering the rheological parameters corresponding to HA concentrations of 6, 8, 10, 12, and 15 mg/mL. For assessing the impact of administration speed, values representative of the typical speed range used in clinical procedures were considered. Simulations were used to estimate shear stress as a function of administration speed for each viscosity level. Results: The findings revealed a directly proportional relationship between viscosity and administration speed with the magnitude of shear stress. Notably, the highest viscosity formulation, when administered at the fastest speed, reached "critical values" of shear stress associated with mechanical damage to cell membranes and cell death. Conversely, lower viscosity HA exhibited reduced stress levels, indicating it as the potentially preferred formulation for injectable cell therapy. The in vitro cell culture assays corroborated the computational simulation results. Conclusions: The administration of HA demonstrates a viscosity- and speed-dependent effect on shear stress, which should be carefully considered for its application in bioprinting and injectable cell therapies.

Morphological analysis reveals the influence of genipin and polyvinyl alcohol on porous morphology on interpenetrated chitosan xerogels

2024-10-29T15:22:08-03:00

The morphological characterization of xerogels composed of chitosan, genipin, and PVA demonstrates that their porous architecture is essential to their function as scaffolds for tissue engineering, with significant impacts on absorption properties, cell viability, and potential for biomedical application. SEM and microCT analysis confirmed that these xerogels possess a highly porous internal morphology, with interconnected pores forming an interpenetrating polymeric network, free from phase separation between chitosan and PVA. Hemocompatibility assays confirmed the non-cytotoxic nature of these materials. Varying genipin concentrations showed that lower concentrations produce more heterogeneous pore sizes, while higher concentrations yield a uniform pore distribution, likely due to the increased availability of crosslinking sites. Additionally, the degree of anisotropy increases with both higher genipin and PVA concentrations, suggesting enhanced alignment within the three-dimensional structure. The total open pore volume, which ranges from 88% to 93%, is modifiable based on the concentrations of genipin and PVA. These insights indicate that these xerogels are viable candidates for clinical applications, particularly as potential substitutes for nucleus pulposus, given their high swelling capacity, porosity, interconnectivity, biocompatibility, and adaptable morphological characteristics.

Characterization of 3D-Printed B-TCP Scaffolds with Enhanced Microstructure, Mechanical Properties, and Cell Compatibility

2024-11-18T12:03:26-02:00

Achieving bone regeneration in large defects caused by trauma, pathology and atrophy is a challenge. Innovative implant materials are emerging as alternatives to autografts in regenerative medicine. 3D-printed B-tricalcium phosphate (B-TCP) scaffolds have emerged as a promising solution for bone tissue replacement, offering patient-specific implants without relying on donors or transplantation. There are many open questions that need to be addressed before they can be used on a large scale. The analysis of sintering temperatures and the different crystalline phases, the in-depth evaluation of the microstructure and its biological response, as well as the assessment of suitable mechanical properties are some of these. The present study carried out a comprehensive characterization of the microstructure of commercial 3D-printed B-TCP using X-ray diffraction coupled with Rietveld refinement, X-ray microtomography and scanning electron microscopy. In addition, blood and cell compatibility tests were carried out using MG63 cells. The imaging techniques revealed the influence of the sintering treatment on the microstructure, resulting in an increase in the average pore size, efficient coalescence between particles and a shrinkage effect at higher temperatures. This behavior had a direct impact on the mechanical properties and cell adhesion behavior. Blood compatibility showed no significant differences between all the samples. However, the material sintered at 1200 °C showed better mechanical properties and a better behavior in the adhesion and proliferation of MG63, which were correlated with a higher density, improved mechanical properties and interconnected porosity, which play a key role in improving osteoblastic function.

Development of PCLMA/HAp-Si composite resin for vat photopolymerization 3D printing

2024-10-29T15:12:06-03:00

A photopolymerizable composite resin based on polycaprolactone methacrylate (PCLMA) was developed with functionalized hydroxyapatite (HAp-Si) to enhance the phase affinity between the polymer matrix and inorganic filler, thereby creating a stable resin suitable for 3D printing. Hydroxyapatite was functionalized with 3-aminopropyltrimethoxysilane (APTES) to produce HAp-Si, as confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Polycaprolactone diol (PCLdiol) was successfully modified into PCLMA through the substitution of hydroxyl groups with methacrylate groups, as confirmed by FTIR, which also resulted in an increase in the number-average molecular weight (Mn). Scanning Electron Microscopy (SEM) images confirmed well-dispersed HAp agglomerates, while grafting improved filler distribution within the matrix. Additionally, the resin displayed good dimensional fidelity in 3D printing of cylindrical samples measuring 6.35 x 12.70 mm. These findings suggest that PCLMA-based composite resins are suitable for 3D printing via vat photopolymerization.

Photoluminescent gels based on han purple: new frontiers in biotechnology

2024-10-25T22:47:14-03:00

As a result of the increasing need for new biocompatible materials, polymer-based gels have become promising options. Lately, photoluminescent gels have shown potential for applications in biotechnology and non-invasive tracking due to their ability to emit light when temperature changes occur. This research investigates the incorporation of Han Purple (HP) pigment into a polyethylene glycol/Laponite matrix [92,5/7,5%] (P7L^HP0%) to produce a 3D-printed gel. The gels were examined for possible use as smart sensors, focusing on their optical and thermal characteristics. Formulations with HP concentrations of 0.0%, 0.5%, and 2.0% were prepared, followed by extrusion-based 3D printing. Characterization techniques included FTIR, SEM, and optical analyses (emission and excitation spectra). The findings showed 3D structures with good shape fidelity while FTIR indicated suitable compatibility between HP and the matrix. Optical analysis revealed fluorescence with an excitation band between 400 and 700 nm, with a maximum at 620 nm, and an emission band at 830 - 1000 nm with a peak at 925 nm. This study highlights the potential of HP as a promising material for fluorescent gels in 3D printing, creating new opportunities for biotechnology applications

A Brief Review on Metamaterials Applied to the Healthcare Field

2024-11-18T12:54:41-02:00

Metamaterials refer to any modification of the physical behavior of an existing material through the structured arrangement of repetitive patterns, procedurally generated, which can directly influence its response to deformation, thermal dissipation, and vibrational control. This creates possibilities for solutions that were previously difficult to achieve using conventional materials such as metals, ceramics, polymers, and their composites. The use of this technology has gained momentum with the advent of 3D printing, which has made it possible to apply and create these structures for practical validation. The first structures were modeled at the beginning of the last century, such as the creation of patterns to generate anomalous properties, with diverse applications in fields like optics, thermodynamics, and mechanics, as it allows for material design tailored to specific applications. As a result, applications have expanded to various scales, from millimeter-engineered materials to the nanoscale, drawing the attention of researchers from different fields, including healthcare. This interest stems from the vast array of possibilities and innovations driven by advancements in materials and additive manufacturing, combining these fields to generate increasingly adaptive solutions. In this paper, the concept of metamaterials will be introduced, followed by an exploration of various applications of this technology, including medical equipment, devices, prosthetics, orthotics, and implants, as well as potential future applications of this technology in healthcare.

Bioprinting for Skin: Current Approaches, Technological Advancements and the Role of Artificial Intelligence

2024-11-06T15:15:48-02:00

Bioprinting is a technique adapted from 3D printing to create biological constructs, including high-quality skin substitutes. It matches or exceeds the quality of traditional fabrication methods, offering precision, consistency and speed, critical attributes for large-scale production. A variety of materials are used, most of them natural, such as alginate, chitosan and gelatin, with cells incorporated into the bioink. These cells may belong to the replicated tissue or include stem cells that can differentiate into the desired cell types. Bioprinting enables precise placement of the skin’s layers: hypodermis, dermis and epidermis, allowing for replication of the skin’s complex architecture. Notably, bioprinted skin constructs can closely resemble native tissue, even forming structures like hair follicles and glands as the incorporated cells grow, migrate and differentiate. Artificial intelligence (AI) and machine learning (ML) have recently been applied to enhance efficiency, precision and success. AI tools reduce trial and error by optimizing parameters, bioink composition and quality control. This review explores bioprinting methods, materials and advancements, including in situ bioprinting, the use of robotic devices and the emerging role of artificial intelligence.