Gelatin Type Research Articles

Open Microfluidic Cell Culture in Hydrogels Enabled by 3D-Printed Molds

Cell culture models with tissue-mimicking architecture enable thein vitro investigation of cellular behavior and cell–cell interactions. These models can recapitulate the structure and function of physiological systems and can be leveraged to elucidate mechanisms of disease. In this work, we developed a method to create open microfluidic cell cultures in vitro using 3D-printed molds. The method improves sample accessibility, is simpler to manufacture than traditional closed microfluidic cell culture systems and requires minimal specialized equipment, making it an attractive method for cell culture applications. Further, these molds can generate multiple tissue-mimicking structures in various hydrogels, including blood vessel mimics using endothelial cells (HUVECs). Various geometries were patterned into agarose, gelatin, and collagen type I hydrogels, including star-shaped wells, square wells, round wells, and open channels, to demonstrate the versatility of the approach. Open channels were created in collagen with diameters ranging from 400 µm to 4 mm and in multiple collagen densities ranging from 2 mg/mL to 4 mg/mL. To demonstrate the applicability of our approach for tissue modeling, blood vessel mimics were generated in open channels with diameters of 800 µm and 2 mm, with high cell viability (>89%) for both dimensions. The vessel mimics were used to study the effects of hypoxia on cell viability and CD31 expression by subjecting them to a reduced-O2 environment (∼16% O2). As compared to normoxia conditions, vessel mimics under hypoxia had a reduction in cell viability by 8.3% and CD31 surface expression by 7.4%. Overall, our method enables the generation of different geometries in hydrogels and the development of in vitro tissue mimics for biological applications.

Automated Detection of Porcine Gelatin Using Deep Learning-Based E-Nose to Support Halal Authentication

Authenticating gelatin sources is essential for consumers, particularly those with dietary restrictions or religious concerns regarding pork-derived ingredients. Porcine gelatin, widely used in food and pharmaceutical products, poses considerable challenges for authentication due to its prevalence and the difficulty of detecting it, especially in processed products. In this study, we developed and evaluated an integrated electronic nose (e-nose) system with a Recurrent Neural Network (RNN) to detect and classify gelatin type based on their sources. The e-nose system utilized an array of gas sensors to capture the unique volatile organic compounds (VOCs) associated with each gelatin type, which was subsequently classified by the RNN. The classification performance of the integrated 7-module e-nose system showed promising results based on time points after sample preparation, with accuracy, sensitivity, and AUC of 96.3%, 96.6%, and 98.2% at the 0-hour point, respectively, rising to 99.1% for all three metrics at 2-hour point. The sensitivity of the system also showed an increase over time for single gelatin samples, from 100%, 97.8%, and 91.9% to 98.6%, 99.3%, and 99.3% for pig-derived, cow-derived, and fish gelatin, respectively. For mixed gelatin samples, the system maintained high accuracy, sensitivity, and AUC at 98.2%, 97.9%, and 98.1%, respectively. In conclusion, the integrated e-nose system demonstrates the potential for robust performance in gelatin authentication, paving the way for more efficient and reliable methods of halal food authentication.

Effect of molecular weight and distribution of bovine bone gelatin on the cross-linking gelation induced by transglutaminase.

In this work, six bovine bone gelatin (type B) samples with varying molecular weight (MW) fractions, comprising α-chains, high- and low-MW fractions, were prepared using ethanol precipitation and pH adjustment. The influence of molecular weight distribution (MWD) on gelatin gel strength was examined, along with the effects of these different MW fractions on microbial transglutaminase (MTGase) cross-linking gelatin. The results showed that, without MTGase treatment, high-MW fractions acted as key fillers in the formation of gelatin gel networks, while α-chains and their aggregates played a central role. In contrast, the gelation ability of low-MW fractions was negligible. MTGase cross-linking significantly increased gel strength in both high- and low-MW samples. For instance, the gel strength of the high-MW sample enhanced from 874.4g to 1425.9g, while that of the low-MW sample rose from 186.4g to 340.4g. However, gelatin with an MWD featuring fewer high- and low-MW fractions and a higher proportion of α-chains and their aggregates, exhibited a significant decrease in gel strength, which declined from 740.8g to 560.0g. These findings emphasized the distinct impact of MW fractions on enzymatic gelation.

Core-shell gelatin-chitosan nanoparticles with lysozyme responsiveness formed via pH-drive and transglutaminase cross-linking.

Lysozyme-responsive nanoparticles were fabricated using a hydrophilic protein (gelatin type A) as the core and a hydrophobic polysaccharide (chitosan) as the shell. In this study, curcumin was used as a model molecule for encapsulation and promoted the aggregation of gelatin nanoparticles. Transglutaminase catalyzed both intra-molecular cross-linking within gelatin and inter-molecular cross-linking between gelatin and chitosan. The formation mechanism of gelatin nanoparticles was investigated by molecular docking simulations, circular dichroism spectroscopy, UV-Vis spectroscopy, turbidity analysis, and dynamic light scattering. Results indicated that pH-driven processes can induce molecular conformational changes of gelatin. However, these alone are insufficient to induce nanoparticle formation. Hydrogen bonding, Pi-alkyl interactions, Pi-Pi interactions, and van der Waals forces between gelatin and curcumin are crucial for the core formation. The coating mechanism of chitosan involved covalent bonds catalyzed by transglutaminase and electrostatic interactions, verified by dynamic light scattering and Fourier transform infrared spectroscopy. Physicochemical properties characterization revealed that the core-shell nanoparticles exhibited a maximum encapsulation efficiency of 97.2 ± 0.3 % and an average particle size of 120 ± 21 nm. The core-shell nanoparticles exhibited high thermal and pH stability, with curcumin retention rates exceeding 80 % under acidic, neutral, and weakly alkaline conditions, and detained thermal degradation up to 90 °C. Additionally, lysozyme responsiveness was evaluated by controlled curcumin release with varying lysozyme concentrations, through which enzymatic hydrolysis of chitosan by lysozyme triggered an increased release rate. In summary, core-shell nanoparticles synthesized from gelatin and chitosan may be effective target delivery systems for curcumin.

Preservation of strawberries using jellyfish gelatin-based biodegradable films and coatings under refrigerated storage.

This study investigated the applicability of the biodegradable films and coatings prepared from gelatin extracted from jellyfish Acromitus flagellatus using two extraction methods; conventional hot water extraction and microwave-assisted extraction, for the preservation of strawberries under refrigerated storage (4 °C), compared to biodegradable films and coatings prepared from analytical grade cold water fish skin gelatin and porcine skin gelatin. After 21 days of storage, uncoated strawberries (control group) exhibited visual decay and fungal attacks while coated or film-wrapped strawberries exhibited a better appearance. Coating or wrapping with gelatin films significantly reduced the weight loss of strawberries and the changes in color, hardness, moisture content, pH, titratable acidity, and total soluble solids of coated/film-wrapped fruits during storage were minimal compared to the uncoated fruits. Of the treated groups, the weight loss of gelatin-coated strawberries was significantly lower compared to the fruits wrapped with corresponding gelatin films, in all gelatin types. Furthermore, strawberries coated or wrapped with jellyfish gelatin-based films exhibited comparable properties to the fruits that were coated or wrapped with other two types of gelatin films, indicating the potential use of gelatin extracted from jellyfish in biodegradable films or coating applications in the food industry.

Effect of gelatin nanoparticles’ size and charge on iontophoretic targeted deposition to the hair follicles

Hair follicles (HFs) represent a route of interest to drug delivery for treating several skin conditions. Iontophoresis, on the other hand, is a physical method to enhance drug permeation by applying a low electrical current to the formulation. HFs can be targeted following topical iontophoretic application, as they represent a pathway of lower electrical resistance, as well as a drug reservoir, in particular useful for nanoparticles (NPs), which can preferably accumulate in these structures. Combining both strategies may provide optimal results, but the literature still lacks evidence of the ideal NP characteristics for the iontophoretic drug delivery targeting the HFs. Here, we aimed to evaluate the effect of gelatin NPs’ size and charge under iontophoresis application on NPs’ deposition into the HFs. Four gelatin NP formulations were produced with varying gelatin concentrations and gelatin types (positively charged type A and negatively charged type B), with sizes ranging from 220 to 770 nm. A fluorescent dye, TRITC-dextran 150 kDa, was encapsulated for monitoring NPs deposition. Cutaneous penetration experiments were performed in vitro with and without iontophoresis for 6 h with pig ear skin. The deposition profile was assessed by confocal laser scanning microscopy. Photomicrographs showed a higher accumulation of the larger positively charged NPs (AL), reaching deeper portions of HFs, and showed iontophoresis further increased their deposition, resulting in the highest signal. In conclusion, these findings shed light on the applications of NPs and bring novel treatment opportunities for several diseases compromising the hair follicles.

Characterisation of Snakehead Fish, Channa striata (Bloch, 1793), Byproduct and Its Gelatin Properties

This study aims to identify the characteristics of skin, bones, and scales as a biomaterial byproduct of snakehead fish, Channa striata (Bloch, 1793) before and after the extraction process into gelatin, based on 36 fresh snakehead fish samples. The biomaterials were identified, including their proximate composition (by weight of protein, fat, moisture, ash) collagen, amino acids. The physicochemical properties of gelatin in terms of yield, gel strength, viscosity pH, and functional groups were determined for scales, skin and bones. Combined, these biomaterials made up about 47.74 % of the total byproduct by weight of snakehead fish that would usually be discarded. Moisture and protein content of the skin was higher than that of scales and bone (P < 0.05), and fat content was higher in bone than in skin and scales (P < 0.05). The lowest ash content was in skin (<1 %), compared to scales and bone (P < 0.05). The collagen content of scales was higher than that of skin and bone (P < 0.05). Glycine and proline in the three biomaterials were nearly equal and highest in skin, scale, and bone, respectively. There were significant differences in viscosity and gel strength of the three types of gelatin (P < 0.05), the highest viscosity was in skin gelatin while the best gel strength was in scale gelatin, while pH was not significantly different (P > 0.05). The application of the same method and solvent can produce different properties and characteristics of gelatin, and the presence of functional groups helps determine the occurrence of changes in the secondary structure of gelatin from the three biomaterials.

Transdermal drug delivery of rizatriptan using microneedles array patch: preparation, characterization and ex-vivo/in-vivo study

Given the extensive first pass metabolism of rizatriptan in oral administration and its delayed absorption during a migraine attack as a result of gastric stasis, focus has been on transdermal delivery. The main purpose of this study is to prepare and assess transdermal formulation of rizatriptan, loaded on hydrogel microneedles delivery system, to avoid first pass metabolism and also improve its percutaneous permeation rate. Rizatriptan hydrogel microneedles were prepared using micromolding method and evaluated in terms of mechanical strength, encapsulation efficiency, permeation and in-vivo skin absorption. Different formulations of rizatriptan microneedles (F1–F5) were successfully prepared using different concentrations of carboxymethyl cellulose and gelatin type A. Rizatriptan hydrogel microneedles demonstrated favorable mechanical properties, including withstanding insertion forces, thereby enhancing its skin insertion ability. In permeation study, the percent cumulative drug released after 24 h ranged between 93.1–100% which means that microneedles were able to deliver the drug effectively. For in-vivo study, F3 formulation was selected due to its superior characteristics over other formulations as it exhibited the highest swelling capacity, and demonstrated favorable mechanical properties. Furthermore, F3 showcased the most controlled drug release over a 24-hour period. Relative bioavailability of F3 microneedles was 179.59% compared to oral administration based on the AUC0-24. The observed AUC0-24 in F3 microneedles was statistically significant and 1.80 times greater than that in oral administration. The higher rizatriptan level in the microneedle demonstrated adequate drug permeability through the rat skin, suggesting the potential of microneedles for enhanced therapeutic effectiveness.

Comparative analysis of red skin Tilapia and bovine gelatins as halal alternatives in food industry

Gelatin plays a vital role in the food industry, serving as a thickening agent, emulsifier, wetting agent, and stabiliser. However, conventional sources like mammalian gelatin pose health and societal issues, while poultry gelatin can present risks related to avian flu. Our work was motivated by recent studies focusing on alternative gelatin sources, which prompted further investigation. Our study aimed to extract gelatin from red-skin Tilapia and bovine sources. Both types of gelatin underwent pre-treatment using 0.2 M sodium hydroxide (NaOH) and 0.05 M acetic acid (CH3COOH) at 27ºC, followed by water extraction at 60°C for 3 hours. Fourier-transform infrared (FTIR) analysis confirmed that the extracted gelatins exhibited peaks similar to commercial gelatin. The extracted fish gelatin (EFG) demonstrated superior gel strength compared to commercial fish gelatin (CFG), whereas commercial bovine gelatin (CBG) exhibited superior gel strength than extracted bovine gelatin (EBG). The protein content of EFG and EBG was comparable, but the fat content was significantly higher in EFG. The foaming capacity was also evaluated, with EFG showing greater capacity than EBG. Our work demonstrates excellent potential of alternative gelatin for usage in various applications and creates new opportunities for the food sector, particularly for halal food production.

Biocompatibility and expression of transcription factors of a type B gelatin-Extracellular Matrix of Porcin Urinary Blader scaffold.

to evaluate a membrane based on type B gelatin (G) and porcine urinary bladder extracellular matrix (PUB-EM), highlighting the potential effect of the combination evaluated by biocompatibility and regulation of the expression of transcription factors involved in tissue regeneration. G-PUB-EM membranes were prepared at 12.5, 25, and 50% w/v, and evaluated for biocompatibility with Fibroblast. Chemical characterization by FTIR-ATR showed complex spectra during crosslinking process with glutaraldehyde. Physical tests were performed in deionized water and PBS for 48 h. A significant increase in swelling was observed during the first 2 h. Biocompatibility testing (MTS) and evaluation of the expression profile of genes involved in the cell cycle (Cyclin-D1 VEGF, TNF and NF-κ-B) by PCR showed an increase in viability in a PUB-EM content-dependent way, except for 50% PUB-EM membrane which showed cytotoxic effects with a decrease in cell viability below 70%. The membranes showed an increase in the expression of some factors of cell cycle, as well as inflammatory processes that could promote tissue repair. 12.5 and 25% gelatin type B/porcine urinary bladder extracellular matrix (G/PUB-EM) based membranes have potential for tissue regeneration applications. The use of membranes based on type B gelatin and porcine urinary bladder for tissue engineering represents a novel strategy. Biocompatibility and signaling pathways play a primary role in tissue repair and wound recovery. Transcription factors that mediate signaling, cell division and vascularization are part of molecules that intervene in the regenerative potential of cells. These techniques will have a significant impact on tissue repair and regeneration and thus stop depending on tissue donors or other surgical sites from the same patient, as is the case with burn patients.

Complex coacervation of low methoxy pectin with three types of gelatins for the encapsulation of fish oil

Herein, the complex coacervation of low methoxy pectin (LMP) with three types of gelatins was explored to encapsulate fish oil. The fish oil@gelatin-LMP complex coacervates with good precipitation separation could be obtained at low gelatin concentrations (Fish gelatin, FG: 10–80 mg/mL; porcine skin gelatin, PSG: 10–40 mg/mL; bovine skin gelatin, BSG: 10–80 mg/mL), high gelatin: fish oil mass ratios (4:1–1:1), appropriate gelatin: LMP mass ratios (3:1–12:1 for FG and PSG, 6:1 for BSG), and appropriate pH (FG: 4.90–5.50; PSG: 4.80–5.40; BSG: 4.10–4.50). FG induced similar loading ability, lower encapsulation ability, and comparable peroxide values to the mammalian gelatins. FG induced higher or similar free fatty acid released percentages to mammalian gelatins in the in vitro gastrointestinal model at low gelatin concentrations (10–40 mg/mL). These results provided useful information to understand the protein-polysaccharide complex coacervation to encapsulate oil-based bioactive substances.

Realizing time-staggered expression of nucleic acid-encoded proteins by co-delivery of messenger RNA and plasmid DNA on a single nanocarrier.

Co-delivery of different protein-encoding polynucleotide species with varying expression kinetics of their therapeutic product will become a prominent requirement in the realm of combined nucleic acid(NA)-based therapies in the upcoming years. The current study explores the capacity for time-staggered expression of encoded proteins by simultaneous delivery of plasmid DNA (pDNA) in the core and mRNA on the shell of the same nanocarrier. The core is based on a Gelatin Type A-pDNA coacervate, thermally stabilized to form an irreversible nanogel stable enough for the deposition of cationic coats namely, protamine sulfate or LNP-related lipid mixtures. Only the protamine-coated nanocarriers remained colloidally stable following mRNA loading and could successfully co-transfect murine dendritic cell line DC2.4 with fluorescent reporter mRNA(mCherry) and pDNA (pAmCyan1).Further investigation of the protamine-coated nanosystem only, the transfection efficiency (percentage of transfected cells) and level of protein expression (mean fluorescence intensity, MFI) of mRNA and pDNA, simultaneously delivered by the same nanocarrier, were compared and kinetically assessed over 48h in DC2.4 using flow cytometry. The onset of transfection for both nucleotides was initially delayed, with levels < 5% at 6h. Thereafter, mRNA transfection reached 90% after 24h and continued to slightly increase until 48h. In contrast, pDNA transfection was clearly slower, reaching approximately 40% after 24h, but continuing to increase to reach 94% at 48h. The time course of protein expression (represented by MFI) for both NAs essentially followed that of transfection. Model-independent as well as model-dependent kinetic parameters applied to the data further confirmed such time-staggered expression of the two NA's where mRNA's rate of transfection and protein expression initially exceeded those of pDNA in the first 24h of the experiment whereas the opposite was true during the second 24h of the experiment where pDNA displayed the higher response rates. We expect that innovative nanocarriers capable of time-staggered co-delivery of different nucleotides could open new perspectives for multi-dosing, pulsatile or sustained expression of nucleic acid-based therapeutics in protein replacement, vaccination, and CRISPR-mediated gene editing scenarios.

Porcine, bovine, and mixed gelatin identification using SPME-GC-MS and chemometrics

Gelatin is a versatile raw material extensively used in the food, cosmetics, and pharmaceutical industries. It is produced globally by partially hydrolyzing collagen derived from pigs and cows, leading to religious and ethical concerns among various communities. Therefore, this study aimed to explore alternative methods to distinguish porcine, bovine, and mixed gelatin by analyzing the unique profiles of their total volatile compounds. The volatilomics method integrated solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) with chemometrics. The results showed that principal component analysis (PCA) of the volatile compounds from gelatin powder had clear classification among porcine, bovine, and mixed gelatin, suggesting the discrimination ability of the method. Furthermore, partial least squares discriminant analysis (PLS-DA) identified distinct marker compounds that significantly contributed to the classification of each gelatin type. The marker compounds for porcine gelatin included 2-decen-1-ol, 2-dodecenal, cyclohexane 1-butenylidene, decane 3,6-dimethyl, cyclohexanone 2-propyl, borinic acid, 3-tetradecyn-1-ol, 2-tridecene, 5,5-dimethyl-1,3-dioxan-2-one, and 2-n-butyl furan. For bovine gelatin, the marker compounds were 2-heptanone 3-methyl, nonane 5-butyl, tridecane 6-methyl, 1-hexacosanol, nonane 3-methyl-5-propyl, undecane 3-methyl, octane 4-methyl, 2,4-undecadienol, and 1-hexadecanol 2-methyl.

The Diels-Alder Cross-Linked Gelatin/Dextran Nanocomposite Hydrogels with Silver Nanoparticles for Wound Healing Applications: Synthesis, Characterization, and In Vitro Evaluation.

Wound healing involves a sophisticated biological process that relies on ideal conditions to advance through various stages of repair. Modern wound dressings are designed to imitate the natural surroundings around cells and offer properties such as moisture regulation, strength, and antimicrobial defense to boost healing. A recent research project unveiled a new type of gelatin (Gel)/dextran (Dex) hydrogels, linked through Diels-Alder (D-A) reactions, loaded with silver nanoparticles (Ag-NPs) for cutting-edge wound treatment. Gel and Dex were chemically modified to form the hydrogels via the D-A reaction. The hydrogels were enriched with Ag-NPs at varying levels. Thorough analyses of the hydrogels using methods like NMR, FT-IR, and SEM were carried out to assess their structure and nanoparticle integration. Rheological tests displayed that the hydrogels had favorable mechanical attributes, particularly when Ag-NPs were included. The hydrogels demonstrated controlled swelling, responsiveness to pH changes, and were non-toxic. Testing against E. coli showcased the strong antibacterial activity of the nanocomposite hydrogels in a concentration-dependent manner. This investigation showcased the promise of these bioactive nanocomposite hydrogels in promoting speedy wound healing by maintaining a moist environment, offering an antimicrobial shield, and ensuring mechanical support at the wound site.

Physicochemical and digestible properties of corn starch/gelatin complexes: Effect of pH, type of gelatin, and gelatin/starch ratio

Reducing the starch digestibility is particularly important for the prevention of obesity, diabetes and other related diseases. This work evaluated the effects of type-A gelatin (GA) or type-B gelatin (GB) of different ratios (12.5%, 25.0% and 50.0%, gelatin/starch, w/w) on the in vitro digestibility of corn starch (CS) at pH 4.0, 5.0 and 6.0. The complexation of CS and gelatin was electrostatic interactions and hydrogen bonds. The gelatin addition increased the turbidity of the system, the gelatinization temperature of CS, decreased the rapidly digestible starch (RDS) content, crystallinity, gelatinization enthalpy and viscosity of CS, and embedded within the internal CS matrix. At the same pH, the RDS content decreased with the increase of GA/CS or GB/CS ratio except for the TS -25.0%GA sample at pH 4.0. Ranked in order of RDS content, the pH values of the complexes were generally as follows: pH 5.0 > pH 6.0 > pH 4.0. Compared to GB, GA significantly reduced RDS content of CS under the same gelatin/starch ratio and pH conditions. The TS-25.0%GA complex exhibited the lowest RDS content of 56.36% at pH 4.0. These results will help to learn more about the mechanism of interaction between CS and gelatin, as well as the development of low content RDS corn starch-based food.

Reconstructing Curves: A Bottom-Up Approach toward Adipose Tissue Regeneration with Recombinant Biomaterials.

The potential of recombinant materials in the field of adipose tissue engineering (ATE) is investigated using a bottom-up tissue engineering (TE) approach. This study explores the synthesis of different photo-crosslinkable gelatin derivatives, including both natural and recombinant materials, with a particular emphasis on chain growth and step growth polymerization. Gelatin type B (Gel-B) and a recombinant collagen peptide (RCPhC1) are used as starting materials. The gel fraction and mass swelling properties of 2D hydrogel films are evaluated, revealing high gel fractions exceeding 94% and high mass swelling ratios >15. In vitro experiments with encapsulated adipose-derived stem cells (ASCs) indicate viable cells (>85%) throughout the experiment with the RCPhC1-based hydrogels showing a higher number of stretched ASCs. Triglyceride assays show the enhanced differentiation potential of RCPhC1 materials. Moreover, the secretome analysis reveal the production of adipose tissue-specific proteins including adiponectin, adipsin, lipocalin-2/NGAL, and PAL-1. RCPhC1-based materials exhibit higher levels of adiponectin and adipsin production, indicating successful differentiation into the adipogenic lineage. Overall, this study highlights the potential of recombinant materials for ATE applications, providing insights into their physico-chemical properties, mechanical strength, and cellular interactions.

Tilapia head gelatins to stabilize fish oil emulsions and the effect of extraction methods

The preparation and use of gelatins from fish by-products have attracted much attention in the field of food science. Herein, four types of tilapia head gelatins were extracted and characterized: hot water-pretreated gelatin (HWG), acetic acid-pretreated gelatin (AAG), sodium hydroxide-pretreated gelatin (SHG), and pepsin enzyme-pretreated gelatin (PEG). The gel strength values followed the order: PEG (74 ± 1 Bloom) > AAG (66 ± 1) > HWG (59 ± 1) > SHG (34 ± 1). The foaming properties, fish oil emulsion viscosity, emulsion activity, and emulsion stabilization ability followed this order: PEG > HWG ≥ AAG > SHG. The effect mechanisms of extraction methods and gelatin concentrations on the emulsion stability involved the interfacial tension, emulsion viscosity, and fat-binding capacity. This work provided important knowledge for analyzing the relations between the structure and function of gelatin. It also provided a high-value application method of fish wastes.

Citric Acid Cross-Linked Gelatin-Based Composites with Improved Microhardness.

The aim of this study is to investigate the influence of cross-linking and reinforcements in gelatin on the physico-mechanical properties of obtained composites. The gelatin-based composites cross-linked with citric acid (CA) were prepared: gelatin type B (GB) and β-tricalcium phosphate (β-TCP) and novel hybrid composite GB with β-TCP and hydroxyapatite (HAp) particles, and their structure, thermal, and mechanical properties were compared with pure gelatin B samples. FTIR analysis revealed that no chemical interaction between the reinforcements and gelatin matrix was established during the processing of hybrid composites by the solution casting method, proving the particles had no influence on GB cross-linking. The morphological investigation of hybrid composites revealed that cross-linking with CA improved the dispersion of particles, which further led to an increase in mechanical performance. The microindentation test showed that the hardness value was increased by up to 449%, which shows the high potential of β-TCP and HAp particle reinforcement combined with CA as a cross-linking agent. Furthermore, the reduced modulus of elasticity was increased by up to 288%. Results of the MTT assay on L929 cells have revealed that the hybrid composite GB-TCP-HA-CA was not cytotoxic. These results showed that GB cross-linked with CA and reinforced with different calcium phosphates presents a valuable novel material with potential applications in dentistry.

Surface modification of titanium foams for modulated and targeted release of drug-loaded biocompatible hydrogel. Proof of concept

Bone-tissue replacement surgeries usually need medication to mitigate implant rejections or prevent local infections. In this study, a modulated and targeted tetracycline (TC) loaded gelatine type A hydrogel is release from Ti foams as a proof of concept for an innovative and intelligent drug release system. The drugs are released in a localized and controlled manner. The Ti foams fabricated by the space holder technique were surface modified by two different techniques of surface modification, i.e., thermal oxidation and acid etching, to assess their influence on TC release. The characterization carried out after the surface modification indicated that samples modified with acid etching have produced a rougher surface, increasing the diameter of pores (from 500 μm to 700 μm, approximately) due to coalescence of pores. The increase of pore roughness has demonstrated the delaying of the TC release due to the greater adhesion between the surface roughness and the hydrogel. In addition, the increase of pore size improves the possibility to infiltrate high amount of drug-loaded biocompatible hydrogel. Opposite, oxidized surface samples have generated a rutile type TiO2 layer that, because of its hydrophilic nature facilitate the degradation of the hydrogel, and consequently, the TC release from the Ti foams. Therefore, both methods show opposite behaviour, available to increase (acid etching) or decrease (thermal oxidation) the TC release thanks to the different kinetic degradation of hydrogel, as a potential way for drug-release from metallic implants. Thus, while acid-etched samples showed maximum TC release value of 35 wt%, after 120 min, the oxidized samples surpassed the 40 % of TC release after same 120 min of release time treatment.

Three-Dimensional Microfibrous Scaffold with Aligned Topography Produced via a Combination of Melt-Extrusion Additive Manufacturing and Porogen Leaching for In Vitro Skeletal Muscle Modeling.

Skeletal muscle tissue (SMT) has a highly hierarchical and anisotropic morphology, featuring aligned and parallel structures at multiple levels. Various factors, including trauma and disease conditions, can compromise the functionality of skeletal muscle. The in vitro modeling of SMT represents a useful tool for testing novel drugs and therapies. The successful replication of SMT native morphology demands scaffolds with an aligned anisotropic 3D architecture. In this work, a 3D PCL fibrous scaffold with aligned morphology was developed through the synergistic combination of Melt-Extrusion Additive Manufacturing (MEAM) and porogen leaching, utilizing PCL as the bulk material and PEG as the porogen. PCL/PEG blends with different polymer ratios (60/40, 50/50, 40/60) were produced and characterized through a DSC analysis. The MEAM process parameters and porogen leaching in bi-distilled water allowed for the development of a micrometric anisotropic fibrous structure with fiber diameters ranging from 10 to 100 µm, depending on PCL/PEG blend ratios. The fibrous scaffolds were coated with Gelatin type A to achieve a biomimetic coating for an in vitro cell culture and mechanically characterized via AFM. The 40/60 PCL/PEG scaffolds yielded the most homogeneous and smallest fibers and the greatest physiological stiffness. In vitro cell culture studies were performed by seeding C2C12 cells onto a selected scaffold, enabling their attachment, alignment, and myotube formation along the PCL fibers during a 14-day culture period. The resultant anisotropic scaffold morphology promoted SMT-like cell conformation, establishing a versatile platform for developing in vitro models of tissues with anisotropic morphology.