Albumin Foams Research Articles

In‐Foam Bioprinting: An Embedded Bioprinting Technique with Self‐Removable Support Bath

The emergence of embedded three‐dimensional (3D) bioprinting has revolutionized the biofabrication of free‐form constructs out of low‐viscosity and slow‐crosslinking hydrogels. Using gel‐based support baths has limitations including lack of proper oxygenation and nutrition and complications with bath removal. Herein, a novel‐embedded 3D bioprinting technique is developed with an albumin foam support bath as a promising substitute. The proposed technique, in‐foam bioprinting, offers excellent printability and convenience in bath removal while providing cells with easy access to oxygen and nutrients. The foam‐based support bath is characterized through foam stability and rheological tests. The bubble size in the foam is measured to study the change in the structure of the bath due to the coalescence of the bubbles over time. Free‐form structures are successfully 3D printed with thermoresponsive chitosan‐based bioinks to demonstrate the capability of the in‐foam bioprinting technique. The viability of bioprinted fibroblast L929 cells is studied over a seven‐day period, showing high cell viability of over 97%, which is attributed to the abundance of oxygen and nutrition in the foam support bath. Importantly, in‐foam bioprinting is beneficial for biofabricating large samples with a long printing time without jeopardizing cell viability.

Development of 3D-Printable Albumin-Alginate Foam for Wound Dressing Applications.

In this article, a method to develop 3D printable hybrid sodium alginate and albumin foam, crosslinked with calcium chloride mist is introduced. Using this method, highly porous structures are produced without the need of further postprocessing (such as freeze drying). The proposed method is particularly beneficial in the development of wound dressing as the printed foams show excellent lift-off and water absorption properties. Compared with methods that use liquid crosslinker, the use of mist prevents the leaching of biocompounds into the liquid crosslinker. 3D printing technique was chosen to provide more versatility over the wound dressing geometry. Calcium chloride and rhodamine B were used as the crosslinking material and the model drug, respectively. Various biomaterial inks were prepared by different concentrations of sodium alginate and albumin, and the fabricated scaffolds were crosslinked in mist, liquid, or kept without crosslinking. The effects of biomaterial composition and the crosslinking density on the wound dressing properties were assessed through printability studies. The mist-crosslinked biomaterial ink composed of 1% (w/v) sodium alginate and 12% (w/v) albumin showed the superior printability. The fabricated scaffolds were also characterized through porosity, mechanical, degradation, and drug release tests. The mist-crosslinked scaffolds showed superior mechanical properties and provided relatively prolonged drug release.

The Effect of pH and Concentration on the Textural and Rheological Properties of Egg Albumin Foams

The effect of different concentrations (i.e. 0.1% - 1%) and pH (7.0 and 4.0) on the textural/physical and rheological properties of egg albumin foams was investigated. The findings indicated that the stability and overrun of the foams were higher in the case of the foams made at pH = 4.0 and with the highest concentration of egg albumin (1%). The apparent viscosity of the albumin solution was significantly (p<0.05) higher at pH = 4.0 and in the presence of the higher concentrations of egg albumin (0.5% - 1%). All of the rheological parameters in amplitude sweep test indicated a weak structure of the foam made at pH = 7.0 and in the presence of a low concentration of egg albumin (0.1%). Regardless of the pH, the values for tan (δ) in the frequency sweep test indicated a weak biopolymer foam structure in the case of all samples. Yield stress was greater in the sample manufactured at pH = 4.0. Overall, the findings suggested that both protein concentration and pH had substantial effects on the rheological and physical properties of egg albumin foams.

Physical and Rheological Properties of Egg Albumin Foams Are Affected by Ionic Strength and Basil Seed Gum Supplementation

In this study, the effect of ionic strength and basil seed gum (BSG) on the foaming properties of egg white albumin (EWA) was studied. The foam was prepared with 1% EWA (w/v) in the presence of different concentrations of sodium chloride (NaCl; 0, 0.5, and 1% w/v) and BSG (0, 0.1, and 0.3% w/v). The results showed that foam density and foam stability of EWA significantly (p<0.05) increased with an increase in BSG concentration (from 0 to 0.3% w/v). On the contrary, an increase in NaCl concentration (from 0 to 1% w/v) increased foam overrun but decreased foam density. Amplitude rheological parameters indicated an improvement in foam structure with increasing NaCl concentration. In addition, an elastic structure was obtained in the case of the foams with the higher concentrations of NaCl. Elastic modulus (G′) was higher than loss modulus (G″) in the frequency range, and there was low frequency dependency in all of the samples. In constant frequency of 1 Hz, tangent (δ) was the lowest in the sample containing 1% NaCl (w/v), but without BSG. There was a decrease in yield stress values with increasing BSG concentration; however, the increase in NaCl concentration led to an increase in yield stress. The highest yield stress (37 Pa) belonged to the sample containing 1% NaCl, but without BSG. Overall, it was found that both NaCl and BSG could substantially improve the rheological and foaming properties (in particular, foam stability) of egg white albumin.

Basil Seed Gum Enhances the Rheological and Physical Properties of Egg Albumin Foams

Basil Seed Gum Enhances the Rheological and Physical Properties of Egg Albumin Foams

Maltodextrins produced from chemically modified starches as agents affecting stability and rheological properties of albumin foam

The purpose of this work was to study the influence of maltodextrins produced from chemically modified starches (stabilised, cross-linked, and double modified) on the stability and rheological characteristics of foam produced from egg albumin. A significant effect was found, related to the type of chemically modified starch used to produce the maltodextrins, on the stabilising properties of the latter and on the viscoelastic properties of the foam systems. Maltodextrins produced from distarch phosphate exhibited the best foam stabilising properties, while maltodextrins from acetylated starch had no favourable effect on the stability of the foam. Moreover, it was found that foam stability decreased as the dextrose equivalent (DE) value of the maltodextrin increased. The foams stabilised with maltodextrins exhibited viscoelastic properties, with domination of the storage modulus over the loss modulus, and behaviour similar to weak gels. The susceptibility of the foams to deformation was dependent on the type of maltodextrin and its DE value. The foam stabilised with the DE 6 maltodextrin produced from acetylated distarch phosphate was the most resistant to deformation, while foam with maltodextrin produced from acetylated starch was the least resistant to deformation.

Effect of native potato starch maltodextrins on stability and rheological properties of albumin foams

The aim of this work was to evaluate the effect of dextrose equivalent and concentration of potato maltodextrins on stability and rheological properties of egg albumin foams. It was found that maltodextrins can act as stabilising agents for aerated food systems. This characteristic of maltodextrin depends on its DE value and concentration. The foams containing 20 and 30 wt% of maltodextrin of DE 6 did not undergo destabilisation in time, contrary to the foams with maltodextrins of DE 11 and DE 16. All the foams showed viscoelastic properties with a domination of the elastic ones and they exhibited characteristics typical of a weak gel. The foams with maltodextrins were less susceptible to deformation as compared to the foam without maltodextrin. The susceptibility to deformation of the foams decreased with a decrease in the maltodextrin DE value and with an increase in the maltodextrin concentration.

A SEM Record of Proteins-Derived Microcellular Silicon Carbide Foams

Protein rigid foams based on albumin coreacted with camphor and an aldehyde were converted into silicon carbide (SiC) foams. This was carried out by putting albumin-derived template foams in contact with silicon compounds in liquid phase and calcinating the mix obtained at a relatively low temperature of 500°C to eliminate the protein and leave the SiC foam. The transformation was followed by scanning electron microscopy (SEM) from the natural albumin foams to the gel obtained by infi ltrating them with tetraethyl orthosilicate (TEOS) and to the appearance of the SiC foams after calcination. X-ray diffraction (XRD) and Raman spectra were done to characterise the resulting foam.

Preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam

Vascular thrombosis is a potentially fatal disease. Thrombolysis represents an efficient therapeutic option, although it still presents intrinsic bleeding risks. In order to minimize this problem, intra-thrombus injections, alone or associated with some kind of mechanical thrombectomy, have been used. In this work, a new approach to thrombolysis is presented, where the preparation, characterization and in vitro thrombolytic activity of a novel streptokinase foam are reported. Foams were prepared by mixing albumin solution with CO2 at different volume ratios. Foam stability and apparent viscosity were the parameters used to characterize the foams. The volume ratio between CO2 and albumin solution that yielded the samples with the best properties was used to prepare the thrombolytic foams, where streptokinase was used as the thrombolytic agent. The thrombolytic effect of this foam was assessed in vitro by delivering it intra-thrombus and the results were compared with those of the foam without streptokinase as well as those of a regular streptokinase solution. Both foam stability and viscosity increased as the ratio of CO2:albumin solution increased and the 3:1 ratio was used to incorporate streptokinase. The in vitro thrombolytic activity study revealed that the streptokinase foam caused a 46.6% of thrombus lysis after 30min of experiment against 21 and 31% of those of the foam without streptokinase and the regular streptokinase liquid solution, respectively. Thus, the use of CO2:albumin foam enhanced the in vitro thrombolytic effect of streptokinase, which indicates its potential as a novel vehicle for carrying and delivering streptokinase to targeted thrombi.

Flexible natural tannin-based and protein-based biosourced foams

Flexible tannin foams as opposed to the rigid tannin foams already prepared, were obtained by the addition of an external (non-reacted) plasticizer, namely glycerol. Glycerol was chosen for its high boiling temperature and the lack of evaporation, coupled to its lack of toxicity. Flexible albumin protein foams were also prepared using glycerol as an external plasticizer. Flexibility and spring-back of these experimental foams when subjected to a cyclic compression force followed by spring-back and compression again was quantified by both thermomechanical analysis at different temperatures as well as by compression/spring back hysteresis cycle tests in a universal testing machine. Tannin foams containing formaldehyde and without glycerol have been shown to reach a stress plateau indicative of structure crushing. Tannin foams without formaldehyde but without glycerol too, becomes very fragile, brittle and rigid just two months after their preparation again presenting structure crushing with ageing. Instead, tannin foams without formaldehyde but with glycerol added do not show any change of flexibility with time and remain truly flexible. Albumin foams to which glycerol was added also do not show any change of flexibility with ageing. The glass transition temperature of the materials constituting the foams was measured by thermomechanical analysis.

Localization of the bronchial air leakage in pneumothorax by injection of human albumin foam

To evaluate the efficacy and safety of a new method to determine the bronchus for air leakage in pneumothorax by injection of human albumin foam. In 29 cases with pneumothorax, the bronchus responsible for air leakage was localized by injecting foam of human albumin into target bronchus under direct view of bronchoscopy. The bronchus for air leakage was successfully localized in all the 29 cases of pneumothorax. The average time for locating (from injection of the foam to the localization of the bronchus) was (4.0 ± 1.2) min, and the average amount of 20% human albumin used was (8.0 ± 2.6) ml for each patient. The air leakage was treated accordingly, and occlusion by fibrin glue was successfully carried out in 21 cases and by OB glue in 8 cases. Severe cough was noted in 6, fever in 4, thoracic bleeding in 4 cases, and chest pain in 1 case. Injection of human albumin foam into target bronchus under bronchoscopy was a simple, safe and effective method for the localization of the bronchus for air leakage in pneumothorax.

Synthesis of Ag–Pt alloy nanoparticles in aqueous bovine serum albumin foam and their cytocompatibility against human gingival fibroblasts

Foams of bovine serum albumin (BSA) have been utilized for synthesizing in situ protein capped Ag–Pt alloy nanoparticles. The in vitro cytotoxicity and the rate of proliferation of human gingival fibroblasts (HGFs) in presence of the above synthesized alloy nanoparticles is investigated. Expression profile of protein involved in detoxification, i.e. metallotheonein (MT) were assayed by ELISA and expression of mRNA transcripts by reverse transcription polymerase chain reaction (RT-PCR). Cytotoxicity results suggested that protein capped nano-alloys might be promising candidates for implants and prosthetic material. RT-PCR and ELISA confirmed the expression of MT, in cells treated with the alloy nanoparticles. Morphology variation studied by SEM also confirms that cells treated with alloy nanoparticles present an intact morphology.

Effect of lidocaine on ovalbumin and egg albumin foam stability.

Foam fractionation is a simple separation process that can remove and concentrate hydrophobic molecules such as proteins, surfactants, and organic wastes from an aqueous solution. Bovine serum albumin and ovalbumin have been widely used as model proteins due to their strong foaming potential and low price. Here, we study the effect of lidocaine on albumin foam, since drugs like lidocaine are known to bind with albumin. We observed that lidocaine not only enhances the amount of foam produced but also the stability of that foam as well. The foam stability was evaluated as the decay rate constant of the foam, determined from a change in height (or volume) of the foam over a given time period.

Foam behavior of biological media

A simple method was developed for evaluating foam stability. The influence of KCl and MgSO4 on foam stability of bovine serum albumin foams was investigated. These salts increase foaminess, but diminish foam stability by the same degree. Thus there is little overall.