Starch Microspheres Research Articles

In vivo revascularization and tissue effects of uterine artery embolization with starch microspheres in sheep.

In uterine artery embolization (UAE) for the treatment of fibroids, nondegradable particles permanently occlude the uterine artery (UA). These particles remain in the vessels and can cause secondary undesirable effects, such as severe pain after embolization and fertility issues. In this prospective experimental study, we aimed to evaluate the angiographic recanalization, local and systemic reactions, and uterine damage occurring after performing UAE with newly developed degradable starch microspheres (DSMs) in sheep. Under general anesthesia, eight nonpregnant sheep underwent bilateral UAE using DSMs to achieve stasis. Angiographic evaluation was performed on days 1, 3 and 7 after embolization to assess in vivo recanalization. In addition, the angiographic series were scored via a modified embolization score. A postmortem tissue examination was performed to determine whether DSMs and foreign body inflammatory reactions were present and to assess uterine necrosis. Complete bilateral embolization of the UA and cervicovaginal branches was achieved in all treated animals. Recanalization of the occluded arteries was evident in 25 of 27 arteries during the angiographic evaluation. In all sheep, there were multifocal areas of uterine necrosis, and some uterine vessels contained intraluminal material consistent with DSMs. The average weight of both uterine horns was significantly correlated with both the number of microspheres needed for complete embolization (r = 0.69, ρ<0.01) and the average percentage of necrosis in both uterine horns (r = 0.64, ρ<0.05). Our findings demonstrated the efficacy of vascular embolization with DSM by inducing ischemic changes in the uterus and subsequent recanalization of previously occluded arteries.

Fabrication of crosslinked starch microspheres via water-in-water Pickering emulsion and their application in controlled release of Vitamin C

Green technology for the fabrication of bio-degradable microspheres is exciting and needed. In this study, a new water-in-water Pickering emulsion green technology is proposed for the fabrication of the crosslinked starch microspheres with sodium tripolyphosphate as the crosslinker, polyethylene glycol aqueous solution as the continuous phase (PEG phase) and starch aqueous solution as the dispersed phase (starch phase). The factors that affect the morphology and particle sizes of cross-linked starch microspheres are investigated by laser scanning confocal microscope (LCM) and laser particle size analyzer. The results reveal that the particle sizes of crosslinked starch microspheres are increasing with increased starch concentration. The particle sizes of crosslinked starch microspheres show a first increase and then decrease trend with the increase of the concentration of PEG 20,000 in the PEG phase. The hydrophobic nano silica is used as an emulsifier to form water-in-water Pickering emulsion and shows an obvious effect on the morphology of starch microspheres. When the starch concentration is 20.00 wt%, PEG 20000 concentration is 32.56 wt%, the ratio of starch to PEG phase is 0.20 and the amount of silica is 5.00 wt% of starch, starch microspheres with regular shapes are obtained with the size of about 32.30 ± 0.22 µm. The fabricated cross-linked starch microspheres are non-crystalline and show good water and oil absorption performances. The application of fabricated crosslinked starch microspheres in the adsorption and release of Vitamin C is conducted. The maximum adsorption capacity of crosslinked starch microspheres for Vitamin C reaches 309.9 mg/g. Starch microspheres show a controlled release of Vitamin C in water. This study indicated that crosslinked starch microspheres can be fabricated through a green water-in-water Pickering emulsion technology and may find potential applications in degradable controlled-release microspheres.

A Structural Study on Absorption of Lysozyme in Amorphous Starch Microspheres.

The potential of using proteins as drugs is held back by their low stability in the human body and challenge of delivering them to the site of function. Extensive research is focused on drug delivery systems that can protect, carry, and release proteins in a controlled manner. Of high potential are cross-linked degradable starch microspheres (DSMs), as production of these is low-cost and environmentally friendly, and the products are degradable by the human body. Here, we demonstrate that DSMs can absorb the model protein lysozyme from an aqueous solution. At low amounts of lysozyme, its concentration in starch microspheres strongly exceeds the bulk concentration in water. However, at higher protein contents, the difference between concentrations in the two phases becomes small. This indicates that, at lower lysozyme contents, the absorption is driven by protein-starch interactions, which are counteracted by protein-protein electrostatic repulsion at high concentrations. By applying small-angle X-ray scattering (SAXS) to the DSM-lysozyme system, we show that lysozyme molecules are largely unaltered by the absorption in DSM. In the same process, the starch network is slightly perturbed, as demonstrated by a decrease in the characteristic chain to chain distance. The SAXS data modeling suggests an uneven distribution of the protein within the DSM particles, which can be dependent on the internal DSM structure and on the physical interactions between the components. The results presented here show that lysozyme can be incorporated into degradable starch microspheres without any dependence on electrostatic or specific interactions, suggesting that similar absorption would be possible for pharmaceutical proteins.

Application of Starch Microspheres Modified by Alkyl Polyglucoside as Environmental-Friendly Fluid Loss Additive in Water-Based Drilling Fluids

Application of Starch Microspheres Modified by Alkyl Polyglucoside as Environmental-Friendly Fluid Loss Additive in Water-Based Drilling Fluids

Preparation and Properties of Fomesafen@SiO2-Starch Microspheres for Herbicide-Controlled Release

Preparation and Properties of Fomesafen@SiO₂-Starch Microspheres for Herbicide-Controlled Release

Determination of Density of Starch Hydrogel Microspheres from Sedimentation Experiments Using Non-Stokes Drag Coefficient.

Sedimentation is an important property of colloidal systems that should be considered when designing pharmaceutical formulations. In pharmaceutical applications, sedimentation is normally described using Stokes' law, which assumes laminar flow of fluid. In this work we studied swelling and hydration of spherical cross-linked amorphous starch microspheres in pure water, solutions of sodium chloride, and in pH-adjusted aqueous solutions. We demonstrated that Reynolds numbers obtained in these experiments correspond to the transition regime between the laminar flow and the turbulent flow and, hence, expressions based on the non-Stokes drag coefficient should be used for calculations of sedimentation velocity from known density or for assessment of density from observed sedimentation velocity. The density of starch microparticles hydrated in water was about 1050 kg/m3, while densities obtained from experiment with other liquids were dependent on the liquids' densities. The data indicate that the swelling of the cross-linked starch microparticles as characterized by their densities is not sensitive to pH and salt concentration in the studied range of these parameters.

Thermoresponsive Gels with Embedded Starch Microspheres for Optimized Antibacterial and Hemostatic Properties.

Apart from single hemostasis, antibacterial and other functionalities are also desirable for hemostatic materials to meet clinical needs. Cationic materials have attracted great interest for antibacterial/hemostatic applications, and it is still desirable to explore rational structure design to address the challenges in balanced hemostatic/antibacterial/biocompatible properties. In this work, a series of cationic microspheres (QMS) were prepared by the facile surface modification of microporous starch microspheres with a cationic tannic acid derivate, the coating contents of which were adopted for the first optimization of surface structure and property. Thermoresponsive gels with embedded QMS (F-QMS) were further prepared by mixing a neutral thermosensitive polymer and QMS for second structure/function optimization through different QMS and loading contents. In vitro and in vivo results confirmed that the coating content plays a crucial role in the hemostatic/antibacterial/biocompatible properties of QMS, but varied coating contents of QMS only lead to a classical imperfect performance of cationic materials. Inspiringly, the F-QMS-4 gel with an optimal loading content of QMS4 (with the highest coating content) achieved a superior balanced in vitro hemostatic/antibacterial/biocompatible properties, the mechanism of which was revealed as the second regulation of cell-material/protein-material interactions. Moreover, the optimal F-QMS-4 gel exhibited a high hemostatic performance in a femoral artery injury model accompanied by the easy on-demand removal for wound healing endowed by the thermoresponsive transformation. The present work offers a promising approach for the rational design and facile preparation of cationic materials with balanced hemostatic/antibacterial/biocompatible properties.

Starch microsphere silicon-boron crosslinker for low concentration hydroxypropyl guar gum based fracturing fluid

Hydroxypropyl guar gum (HPG) is a critical thickener to increase viscosity and lubrication to improve the water-based hydraulic fracturing efficiency. However, current crosslinkers require a large amount of HPG (>0.3 wt%) to form gel with sufficient viscosity, and high concentrations of HPG may cause adverse effects to the production and the environment. In this study, a novel starch microsphere silica‑boron crosslinker (SMSB) was developed using starch microspheres as a carrier and γ-aminopropyl triethoxy silane (KH550) as a modifier with an in-house method. Both the rheology and surface reactions of the SMSB-HPG crosslinking system were studied using multiple laboratory experiments and molecular dynamics simulation. The results showed that SMSB crosslinker caused multi-site cross-linking with low concentration (only 0.2 wt%) of HPG molecules, reducing the twisting of single molecular chain in the crosslinking system, enhancing the cross-linking strength between molecular chains, and making HPG molecular chains stretcher in the aqueous solution. The apparent viscosity and viscoelasticity of the HPG system were substantially higher than the organoboron crosslinker, and the temperature resistance of the SMSB-HPG crosslinking system was up to 140 °C. This study provides an alternative green crosslinker for more sustainable industrial applications and provides theoretical basis for the modification of biomaterials.

A durable coating constructed by metal-organic framework and polyphosphazene for flame retardant cotton fabric with enhanced mechanical properties

The extremely flammable cellulose macromolecules in cotton fabrics seriously affect their application in the field of flame retardancy. In this paper, the surface of cotton fabric was modified with citric acid, and then metal-organic framework (UiO-66), cationic starch (St) and polyphosphonitrile (PZS) microspheres containing the transition metal element Zr were sequentially deposited to prepare an efficient and economical cotton fabric. St-PZS double-impregnated cotton fabrics have better thermal stability, flame retardancy and mechanical properties. And the coating does not affect the whiteness and stiffness of the cotton fabric. The results of thermogravimetric analysis showed that cotton/UiO-66/2St-PZS had a higher residual char rate (25.34%) under N2 atmosphere, which was 200.1% higher than that of control cotton (8.28%). In addition, cotton/UiO-66/2St-PZS had a 46.6% reduction in peak heat release, a 31.7% reduction in total heat release, and a 35.3% reduction in the peak of CO2 production compared to control cotton. It is worth noting that the average gross calorific value is 63.3% lower than that of the control cotton, indicating that flame retardant cotton fabrics can effectively inhibit the production of flammable gases. In addition, the tensile strength and elongation at break of cotton/UiO-66/2St-PZS are 458.79 N and 11.04%, respectively. After 20 laundering cycles, the mechanical properties remained almost unchanged.

CsxWO3-doped PEG/sweet potato form-stable composites for light-thermal conversion and energy storage

Abstract Cesium tungsten bronze (CsxWO3)-doped PEG/sweet potato form-stable composites are fabricated through a facile two-step method of lyophilization and vacuum impregnation. Abundant starch microsphere enhances the PEG loading capacity above 72 % and also supplies capillary force as well as hydrogen bonding to improve the form-stability of the composites. Here, the latent heat, relative crystallinity (Xc), and light-thermal conversion efficiency of the system with 0.99 wt% CsxWO3 reach to 137.7 J/g, 97.7 %, and 83.5 %, respectively. The light-thermal conversion efficiency increases from 64.3 % to 91.1 % with 2.00 wt% CsxWO3. Besides, the composites exhibit improved thermal stability and excellent thermal reliability. The prepared bio-based composites with low-cost have broad application prospects in the field of energy storage.

Porous starch microspheres loaded with luteolin exhibit hypoglycemic activities and alter gut microbial communities in type 2 diabetes mellitus mice.

Luteolin (LUT), a natural flavonoid known for its hypoglycemic properties, is primarily sourced from vegetables such as celery and broccoli. However, its poor stability and low bioavailability in the upper digestive tract hinder its application in the functional food industry. To address these challenges, this study employed porous starch (PS) as a carrier to develop PS microspheres loaded with luteolin (PSLUT), simulating its release in vitro. The research assessed the hypoglycemic effects of LUT in type 2 diabetes mellitus (T2DM) mice both before and after PS treatment. In vitro findings demonstrated that PS improved LUT's stability in simulated gastric fluids and enhanced its in vivo bioavailability, aligning with experimental outcomes. PSLUT administration significantly improved body weight, fasting blood glucose (FBG), oral glucose tolerance test (OGTT), pancreatic islet function, and other relevant indicators in T2DM mice. Moreover, PSLUT alleviated abnormal liver biochemical indicators and liver tissue injury caused by T2DM. The underlying hypoglycemic mechanism of PSLUT is thought to involve the regulation of protein kinase B (AKT-1) and glucose transporter 2 (GLUT-2). After four weeks of intervention, various PSLUT doses significantly reduced the Firmicutes to Bacteroidetes ratio at the phylum level and decreased the relative abundance of harmful bacteria at the genus level, including Acetatifactor, Candidatus-Arthromitus, and Turicibacter. This microbial shift was associated with improvements in hyperglycemia-related indicators such as FBG, the area under the curve (AUC) of OGTT, and homeostasis model assessment of insulin resistance (HOMA-IR), which are closely linked to these bacterial genera. Additionally, Lachnoclostridium, Parasutterella, Turicibacter, and Papillibacter were identified as key intestinal marker genera involved in T2DM progression through Spearman correlation analysis. In conclusion, PS enhanced LUT's hypoglycemic efficacy by modulating the transcription and protein expression levels of AKT-1 and GLUT-2, as well as the relative abundance of potential gut pathogens in T2DM mice. These results provide a theoretical foundation for advancing luteolin's application in the functional food industry and further investigating its hypoglycemic potential.

Degradable Starch Microspheres Transarterial Chemoembolization with or without Lipiodol for Liver Metastases from Pancreatic Cancer: A Prospective Randomized Trial.

To evaluate and compare the outcome of patients with liver metastases from pancreatic cancer treated by transarterial chemoembolization (TACE) using two different protocols. In this prospective, randomized, single-center trial, patients were randomly assigned to receive TACE therapy either with degradable starch microspheres (DSM) alone or a combination of Lipiodol and DSM. From the initial 58 patients, 26 patients (13 DSM-TACE, 13 Lipiodol + DSM-TACE) who completed 3 TACE treatments at an interval of four weeks were considered for evaluation of tumor responses. Initial and final MRIs were used to evaluate local therapy response by RECIST 1.1; changes in diameter, volume, ADC value, and survival rate were statistically evaluated. The differences between the DSM-TACE and Lipiodol + DSM-TACE were identified for partial response (PR) as 15.4% versus 53.8%, stable disease (SD) as 69.2% versus 46.2%, progressive disease (PD) as 15.4% versus 0%, respectively (p = 0.068). Median overall survival times for DSM-TACE and Lipiodol + DSM-TACE were 20 months (95% CI, 18.1-21.9) and 23 months (95% CI, 13.8-32.2), respectively (p = 0.565). The one-year survival rates for DSM-TACE and Lipiodol + DSM-TACE were 85.4% and 60.4%, the two-year survival rates were 35.9% and 47.7%, and the three-year survival rates were 12% and 30.9%, respectively. The evaluated local therapy response by RECIST 1. was not significantly different between the two studied groups. A longer overall survival time was observed after Lipiodol + DSM-TACE therapy; however, it was not significantly different.

In vivo study of the utility of selective intra-arterial injection of thiopental for neuroprotection in reversible cerebral ischemia.

Neuroprotective agents are needed to reduce cerebral damage during surgical or neurointerventional procedures including stroke patients. To evaluate if thiopental can be used as a neuroprotective agent when injected intra-arterially in a transient ischemia model. In total, 24 rabbits were studied as four groups of six animals. Group 1 served as the control group. In group 2, transient ischemia was obtained by intracarotid administration of degradable starch microspheres (DSM). Group 3 was administered thiopental intra-arterially via the carotid artery. Group 4 (experimental group) received both thiopental and DSM intra-arterially. DSM and thiopental were administered through a microcatheter placed into the common carotid artery via the central ear artery access. After sacrifice, apoptotic cells in the cerebral tissues of the animals were evaluated in H&E and TUNEL stained slides. There was a significant increase in the number of apoptotic glial or neuronal cells in group 2 compared to the control group and group 3. The mean number of both the apoptotic neuronal cells (6.8 ± 2.1 vs. 2.5 ± 1.3, P < 0.001) and the apoptotic glial cells (9.4 ± 3.1 vs. 4.6 ± 1.6, P < 0.001) were higher in group 2 compared to group 4. In addition, a higher level of neurological improvement was observed in group 4 compared to group 2 based on neurological assessment score. The intra-arterial administration of thiopental has a protective effect on both glial and neuronal cells during temporary cerebral ischemia in low doses.

Preparation of cassava starch-gelatin yolk-shell microspheres by water-in-water emulsion method

This paper reports the preparation and characterization of gelatin-cassava starch microspheres using the water-in-water emulsion technique. The effects of different weight ratios (10: 0, 9: 1, 8: 2, 7: 3, 6: 4, 5: 5) of starch to gelatin on the morphology, structure, thermal properties, and stability of microspheres were investigated. The morphology results showed that most microspheres had spherical shapes and smooth surfaces. When the weight ratio of starch to gelatin was 5: 5, the prepared microspheres formed a stable yolk-shell structure. The swelling capacity of the microspheres increased with the proportion of gelatin, up to 682.3 %. The gelatin and starch in the microspheres were compatible but not miscible. Compared with the native starch, the crystalline structure of microspheres changed from A-type to a mixture of B-type and V-type, and the relative crystallinity decreased. Differential scanning calorimetry results showed that the melting of microspheres involved both gelatin dissolution and starch gelatinization. Due to the formation of composite microspheres, the starch content decreased, and the release of reducing sugars from the microspheres upon hydrolysis was reduced. The gelatin-cassava starch microspheres are simple to prepare, biocompatible, and can be used as a potential material for microencapsulation.

Sedimentation of a starch microsphere: What is usually missed and why?

Gravimetric sedimentation is known as a relatively simple method of determining density of spherical particles. When the method is applied to water-swollen starch microparticles of about submillimeter sizes, it becomes evident that a careful selection of the experimental setup parameters is needed for producing accurate testing results. The main reason for this is that the mean particle density is very close to the density of water, and therefore, a dynamic model accounting for the so-called Bassett history force should be employed for describing the unsteady accelerating particle settling. A main novelty of this study consists in deriving a priori estimates for the settling time and distance.

Starch-entrapped microspheres enhance gut microbiome-mediated anti-obesity effects of resistant starch in high-fat diet induced obese C57BL/6J mice

The prevalence of obesity is growing worldwide and has been extensively linked to gut microbiota dysbiosis. In addition to exercise and physical activity, fiber-rich foods may be a first-line prophylactic to manage obesity. This study investigated in vivo dietary intervention with high-amylose maize starch (HAMS) and starch-entrapped microspheres (MS) to treat high-fat diet induced metabolic disorder and gut microbiome dysbiosis in mice. MS more efficiently controlled body weight as well as adipose tissue mass compared to HAMS. Furthermore, MS significantly reduced blood glucose, insulin, lipid and pro-inflammatory cytokine levels compared to the high-fat diet, while the effects of HAMS were less pronounced. The MS-altered gut microbiota composition favoring Streptococcaceae, Bacilli, Firmicutes and unclassified Clostridiales was predicted to promote fatty acid, pantothenate and Coenzyme A biosynthesis. In line with this, elevated fecal short chain fatty acid (SCFA), in particular, propionate concentration was observed in MS-fed mice. Our study provides novel insights into the mechanistic action of MS on intestinal homeostasis, providing a basis for future dietary therapeutic applications.

A collagen-based layered chronic wound biofilm model for testing antimicrobial wound products.

A new in vitro chronic wound biofilm model was recently published, which provided a layered scaffold simulating mammalian tissue composition on which topical wound care products could be tested. In this paper, we updated the model even further to mimic the dynamic influx of nutrients from below as is the case in a chronic wound. The modified in vitro model was created using collagen instead of agar as the main matrix component and contained both Staphylococcus aureus and Pseudomonas aeruginosa. The model was cast in transwell inserts and then placed in wound simulating media, which allowed for an exchange of nutrients and waste products across a filter. Three potential wound care products and chlorhexidine digluconate 2% solution as a positive control were used to evaluate the model. The tested products were composed of hydrogels made from completely biodegradable starch microspheres carrying different active compounds. The compounds were applied topically and left for 2-4 days. Profiles of oxygen concentration and pH were measured to assess the effect of treatments on bacterial activity. Confocal microscope images were obtained of the models to visualise the existence of microcolonies. Results showed that the modified in vitro model maintained a stable number of the two bacterial species over 6 days. In untreated models, steep oxygen gradients developed and pH increased to >8.0. Hydrogels containing active compounds alleviated the high oxygen consumption and decreased pH drastically. Moreover, all three hydrogels reduced the colony forming units significantly and to a larger extent than the chlorhexidine control treatment. Overall, the modified model expressed several characteristics similar to in vivo chronic wounds.

STARCH BASED MICROSPHERE BIOLASERS

Recently, biolasers whose optical cavity is made of natural materials such as serum-extracted protein, egg white, cellulose, and gelatin have attracted a lot of attention. The advantage of these lasers is their biocompatibility and biodegradability which is significant for biointegration. In this study, we demonstrate that starch is a low-cost and good material for microsphere biolasers. By using a simple emulsion method with a dehydration process, dye-doped starch microsphere lasers with diameters ranging from 40 to 180 μm have been successfully obtained. Lasing properties are investigated and the results show that the lasing threshold is approximately 1.0 μJ and the quality factor can reach 2700. The starch-based microsphere lasers indicate excellent stability after a storage time of a month; thus, they are promising for practical applications in biological and chemical sensors.

TACE for HCC: A critical review of the 2021 CIRSE recommendations with presentation of a technique for a degradable starch microsphere—TACE

AbstractThere is no consensus on which substances and which method should be used for transarterial chemoembolization. A publication commissioned by CIRSE 2021 attempted to formulate recommendations. However, only the spectrum of currently implemented procedures is outlined but no recommendation was made. In this article, therefore, basic considerations regarding the technique of chemoembolization are presented, and the authors discuss fundamental considerations about the embolic materials used, the cytostatic drugs and their dosage, as well as about pain therapy during treatment. Then, a technique is presented which used degradable starch microspheres as an embolic agent. This technique enables multiple treatments over a longer period. However, this proposal is not only evidence‐based but also eminence‐based. What we need are controlled studies that systematically compare different treatment techniques in a sufficient number of patients. This will hopefully help to find the best method for individual patients. Until then, the technique proposed by the authors can be applied.

Modified porous starches loading curcumin and improving the free radical scavenging ability and release properties of curcumin

Maize porous starch-curcumin microspheres were prepared by encapsulating curcumin into cross-linked porous starch and oxidized porous starch to investigate the effect of modified porous starch in embedding and protecting curcumin. The morphology and physicochemical properties of microspheres were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, Zeta/DLS, Thermal stability, and antioxidant activity; the release of curcumin was evaluated with a simulated gastric-intestine model. The FT-IR results revealed that curcumin was amorphously encapsulated in the composite and hydrogen bond formation between starch and curcumin was one of the major driving forces for encapsulation. Microspheres increased the initial decomposition temperature of curcumin, which has a protective effect on curcumin. Modification improved the encapsulation efficiency and the scavenging free radical ability of porous starch. The release mechanism of curcumin from microspheres fits first-order and Higuchi models well in gastric and intestinal models, respectively, indicating that encapsulation of curcumin within different porous starches microspheres enables controlled release of curcumin. To recapitulate, two different modified porous starch microspheres improved the drug loading, slow release and free radical scavenging effects of curcumin. Among them, the cross-linked porous starch microspheres had higher encapsulation and slow release ability for curcumin than the oxidized porous starch microspheres. It provides theoretical significance and data basis for the encapsulation of active substances by modified porous starch.