Light-Triggered Adhesive Silk-Based Film for Effective Photodynamic Antibacterial Therapy and Rapid Hemostasis

Successful control of massive hemorrhage in deep wounds with irregular shape and low elasticity still remains great challenges in the clinic. As the wound sites are usually at risk of bacterial infection, it is necessary to design an ideal hemostatic agent with rapid hemostasis and excellent antibacterial activity. In this study, we developed a light responsive hemostatic film for effective handling of liver bleeding with promising photodynamic therapy against S. aureus onnear infrared (NIR) irradiation. Based on silk fibroin, the film exhibited desirable biocompatibility and mechanical property as a hemostat tape. Significantly, the film tape achieved excellent tissue adhesion and hemostasis in vivo within 2 min of UV exposure, which would have a great potential as a multifunctional biomedical material in the field of tissue repair such as wound healing, bone repair, and nerve regeneration.

Effect Collagen Concentration Tilapia Scales on the Quality of Burn Ointment

Collagen is one of the main connective tissue animal proteins and has been widely used as a biomedical material. Collagen is divided into XIX types. Type I collagen, among others, is obtained from bone, scales and skin. Collagen derived from type I can repair tissue or accelerate tissue regeneration to heal burns. The purpose of this research was to determine the addition of fish scale collagen extract to the characteristics of the burn ointment preparation in accordance with the Indonesian National Standard (SNI) and the best quality. The method used in this research is an experimental method of Completely Randomized Design (CRD) consisting of 4 collagen addition treatments: 0%, 2%, 4% and 6% repeated 5 times. Parameters in this method include physical-chemical parameters (pH, spreadability, shelf life and homogeneity) and organoleptic parameters (appearance, aroma, texture and color). Bayes test results, the concentration of the addition of tilapia scale collagen in the ointment preparation of 4% resulted in a value close to the control treatment. The addition of 4% collagen was the best treatment compared to 2% and 6% with a pH value of 6.12, dispersion of 3.22 cm, safe ointment preparation did not change at all during 28 days of storage. Based on the results of the organoleptic test parameters, the ointment at this concentration had a homogeneous appearance, slightly yellowish white color, a distinctive smell of collagen and a semi-solid texture, this was in accordance with the quality standard of the ointment and had the best quality characteristics.

Cell-derived extracellular matrix enhanced by collagen-binding domain-decorated exosomes to promote neural stem cells neurogenesis

Enhancing neurogenesis of neural stem cells (NSCs) is crucial in stem cell therapy for neurodegenerative diseases. Within the extracellular microenvironment, extracellular matrix (ECM) plays a pivotal role in modulating cell behaviors. However, a single ECM biomaterial is not sufficient to establish an ideal microenvironment. As multifunctional nanocarriers, exosomes display tremendous advantages for the treatments of various diseases. Herein, collagen binding domain peptide-modified exosomes (CBD-Exo) were obtained from the SH-SY5Y cell line infected with lentivirus particles encoding CBD-lysosome associated membrane glycoprotein 2b (CBD-Lamp2b) to improve the binding efficiency of exosomes and ECM. An exosomes-functionalized ECM (CBD-Exo/ECM) was then constructed via the interaction between CBD and collagen in ECM. Then, CBD-Exo/ECM was employed as a carrier for NSCs culture. The results showed that CBD-Exo/ECM can support the neurogenesis of NSCs with the percentage of proliferation marker EdU-positive (35.8% ± 0.47% vs. 21.9% ± 2.32%) and neuron maker Tuj-1-positive (55.8% ± 0.47% vs. 30.6% ± 2.62%) were both significantly increased in the exosomes-functionalized ECM system. This exosomes-functionalized ECM was capable to promote the cell proliferation and accelerate neuronal differentiation of NSCs, providing a potential biomedical material for stem cell application in tissue engineering and regenerative medicine.

Microgalvanic Corrosion of Mg–Ca and Mg–Al–Ca Alloys in NaCl and Na2SO4 Solutions

As a kind of potential biomedical material, Mg–Ca alloy has attracted much attention. However, the role of Ca-containing intermetallics in microgalvanic corrosion is still controversial. In 0.6 mol/L NaCl and Na2SO4 solutions, the microgalvanic corrosion behavior of the second phase and Mg matrix of Mg–Ca and Mg–Al–Ca alloys was examined. It was confirmed that the Mg2Ca phase acts as a microanode in microgalvanic corrosion in both NaCl and Na2SO4 solutions, with the Mg matrix acting as the cathode and the Al2Ca phase acting as the microcathode to accelerate corrosion of the adjacent Mg matrix. It was also found that Cl− and SO42− have different sensibilities to microgalvanic corrosion.

A Novel Alloy Development Approach: Biomedical Equiatomic Ta-Nb-Ti Alloy

In the present manuscript, we report on the properties of an equiatomic Ta-Nb-Ti alloy as the basis for a novel, biomedical, multi-component alloy development. The alloy was produced using an arc melting furnace under Ar atmosphere, metallographically prepared, and investigated respectively. Furthermore, the alloy produced, as well as samples of elemental Ta, Nb, alloy Co-28Cr-6Mo, and alloy Ti-6Al-4V, were prepared with defined 1200 grit SiC grinding paper. The topography of the surfaces was evaluated using confocal microscopy and contact angle measurements subsequently. Afterwards, the biocompatibility of the novel alloy Ta-Nb-Ti was evaluated by means of cell (osteoblast) attachment as well as monocyte inflammatory response analysis. First results indicate competitive osteoblast attachment, as well as comparable expressions of fibrosis markers in comparison to conventionally used biomedical materials. In addition, the Ta-Nb-Ti alloy showed a markedly reduced inflammatory capacity, indicating a high potential for use as a prospective biomedical material.

Fused filament fabrication of biodegradable polylactic acid reinforced by nanoclay as a potential biomedical material

Fused filament fabrication (FFF) is one of the most common 3D printing techniques having considerable potential in various fields such as pharmaceutical, medical, aerospace, and automotive. One of the impediments of FFF components is their lower mechanical performance compared with those from conventional fabrication methods. This work aims to investigate the effect of adding nanoclay due to being nontoxic to the biodegradable polylactic acid (PLA) polymer matrix for medical applications. PLA granules were melt-compounded by a twin-screw extruder with nanoclay at 2 and 4 wt.%, and then, PLA and PLA/nanoclay filaments were produced using a single-screw extruder. An L9 orthogonal array of the Taguchi approach was utilized as the design of the experiment tool to study the process in detail considering nanoclay content, nozzle temperature and raster angle as material and processing parameters. The dispersion of nanoclay in the PLA matrix was assessed by X-ray diffraction test. The results indicated that the tensile strength was enhanced by 4.6% and 15.3% using the addition of 2 and 4 wt.% of nanoclay, respectively. The microscopic observations showed that the bonding between the rasters and between the contours and rasters was improved by increasing the temperature, and consequently, led to higher tensile strength values. The results revealed that the tensile strength of 38.9 MPa was obtained at the optimum condition.

Study of Titanium–Silver Monolayer and Multilayer Films for Protective Applications in Biomedical Devices

The search for coatings that extend the useful life of biomedical devices has been of great interest, and titanium has been of great relevance due to its innocuousness and low reactivity. This study contributes to the investigation of Ti/Ag films in different configurations (monolayer and multilayer) deposited by magnetron sputtering. The sessile droplet technique was applied to study wettability; greater film penetrability was obtained when Ag is the external layer, conferring high efficiency in cell adhesion. The morphological properties were characterized by SEM, which showed porous nuclei on the surface in the Ag coating and crystals embedded in the Ti film. The structural properties were studied by XRD, revealing the presence of TiO2 in the anatase crystalline phase in a proportion of 49.9% and the formation of a silver cubic network centered on the faces. Tafel polarization curves demonstrated improvements in the corrosion current densities of Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti and Ti/Ag compared to the Ag coating, with values of 0.1749, 0.4802, and 2.044 nA.m−2, respectively. Antimicrobial activity was evaluated against the bacteria Pseudomonas aeruginosa and Bacillus subtilis and the yeasts Candida krusei and Candida albicans, revealing that the Ti/Ag and Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti coatings exhibit promise in biomedical material applications.

CHARACTERIZATION AND COMPARISON OF MECHANICAL PROPERTIES AND CORROSION RESISTANCE OF TI-10MO-20NB, TI-6AL-4V AND TI-CP ALLOYS FOR BIOMEDICAL APPLICATIONS

One of the main biomedical material for implants, the Ti-6Al-4V alloy, over time generates oxides of V and Al that accumulate in the body and cause cytotoxic effects. Researches have been making an effort for developing an alternative β metastable Ti alloy that combines corrosion resistance, biocompatibility and good mechanical properties. In view of this scenario, the present work aims to characterize a Ti-10Mo-20Nb alloy and compare the results obtained with a commercial purity Ti alloy and Ti-6Al-4V alloy. Ti-10Mo-20Nb samples were subjected to heat treatment at 1000°C, after that they were water quenched. A hot swagging process at 900°C was applied resulting on a cross section reduction of 80%. The alloy was characterized by optical microscopy, scanning electron microscopy (SEM), Vickers microhardness and the linear polarization technique. For the Ti-10Mo-20Nb alloy the ratio between the hardness and the elastic modulus was of 3.22, the hardness value of 238 HV and the elastic modulus of 74 GPa. The Ti-10Mo-20Nb alloy showed a better mechanical as well as biological compatibility due to the non-cytotoxic of its alloy elements, Mo and NB, in spite of the lower corrosion resistance value when compared to other alloys, it is still possessing reasonable resistance to corrosion and develops a remarkable passivation layer. As such Ti-10Mo-20Nb is a promising alternative for biomedical applications due to its superior mechanical properties and better biocompatibility with human bone.