Efficiency of ultrasonic treatment of polysaccharide from brown algae Chimica Techno Acta LETTER published by Ural Federal University 2021, vol. 8(4), № 20218414 eISSN 2411-1414; chimicatechnoacta.ru DOI: 10.15826/chimtech.2021.8.4.14 1 of 4 Efficiency of ultrasonic treatment of polysaccharide from brown algae Victoria E. Suprunchuk * North-Caucasus Federal University, 355017 Pushkin st., 1, Stavropol, Russia * Corresponding author: vsuprunchuk@ncfu.ru This short communication (letter) belongs to the MOSM2021 Special Issue. © 2021, The Authors. This article is published in open access form under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Abstract Ultrasonic exposure can be used for depolymerization of brown algae polysaccharides. However, its effectiveness depends on several fac- tors, including cavitation activity in the treatment medium. There- fore, the purpose of the work was to determine the cavitation activi- ty and the effectiveness of the ultrasonic exposure to fucoidan in or- der to optimize the processing processes of polysaccharide from brown algae. A change in cavitation activity was revealed depending on the composition of the processing environment, as well as on the intensity of ultrasonic exposure with a constant frequency of the ul- trasonic wave. Similar dynamics of change of cavitation activity were established at the intensity of ultrasonic treatment of 100 and 133 W/cm2 with amplification of electric signal at the increase of ul- trasound intensity. The use of SDS in the processing medium led to an increase in cavitation activity to 14.9±0.47 mV. Treatment of the fucoidan solution for 40 minutes under various conditions allowed to obtain fractions with a change in the average hydrodynamic particle diameter from 113 nm (100 W/cm2) to 85 nm (200 W/cm2) and 124 nm (SDS). Keywords fucoidan cavitation nanoparticles depolymerization Received: 02.11.2021 Revised: 16.12.2021 Accepted: 20.12.2021 Available online: 23.12.2021 1. Introduction Fucoidans are of great interest among biopolymers of ma- rine origin. Fucoidan is a branched sulfated heteropolysac- charide isolated from brown algae and some marine inver- tebrates [1]. Fucoidan has anticancer [2], antithrombic [3], anticoagulant [4], antioxidant [5], antiviral [6] activity and other pharmacologically important properties and its use is approved by the FDA. However, as a rule, this polysaccha- ride has a high molecular weight, which limits its industrial use. Therefore, we can make a conclusion that depolymeri- zation of fucoidan is considered an urgent task. Ultrasonic treatment is often used in order to lower the molecular weight of polymers, in polysaccharides in particular [7, 8]. This method is simple and environmentally friendly. Ultra- sonic processing is based on the phenomenon of cavitation. When treated with ultrasonic, the cavities are formed in the environment – cavitation bubbles. As a result of the cavita- tion bubble collapse, a shock wave is created with the for- mation of an acoustic flow leading to the formation of tur- bulence due to the continuous formation and collapse of cavities in the system. In addition, shock waves, intense local heating (about 5000 °C) and high pressure (about 1000 atm) are created [9]. As a result of the collapse of such bubbles, sufficient energy is released to break bonds in any polymeric materials [10]. However, the effectiveness of ultrasonic treatment de- pends on a number of factors, one of which is the cavitation activity in the treatment medium. Detection of cavitation activity will allow determining the optimal rate of destruc- tion of the biopolymer. Therefore, the purpose of the work was to determine the cavitation activity and the effective- ness of ultrasonic treatment to fucoidan in order to opti- mize the processing of polysaccharide from brown algae. The measurement of cavitation intensity was based on re- cording acoustic noise as an electrical signal. 2. Experimental For ultrasonic treatment, polysaccharide obtained from brown algae Fucus vesiculosus was used according to the procedure presented in [11] with some changes. Subse- quent cleaning was carried out in accordance with the work of A.M. Urvantsev, I. Yu. Bakunin, N. Yu. Kim and others [12]. The resulting fucoidan was dispersed in deion- ized water at a concentration of 10 mg/ml. http://chimicatechnoacta.ru/ https://doi.org/10.15826/chimtech.2021.8.4.14 https://orcid.org/0000-0002-5587-8262 http://creativecommons.org/licenses/by/4.0/ Chimica Techno Acta 2021, vol. 8(4), № 20218414 LETTER 2 of 4 The ultrasonic waves generated by means of the ultra- sonic UIP1000hd processor with a power of 1 kW (Hielscher Ultrasonics GmbH, Germany) with a frequency of 20 kHz induced through sonotrode. In the first case, the sonotrode was placed in an aqueous fucoidan solution and the ultrasonic intensity was varied to 100, 133, 200 W/cm2. In the second case, the composition of the medium was varied by introducing auxiliary substances into an aqueous solution of fucoidan while maintaining the intensity of ultrasonic exposure. Surfactants (SDS, PEG-400) were used as excipients. Ultrasonic treatment of fucoidan was carried out for 40 minutes with constant cooling with the help of an ice bath with temperature con- trol within the range of 45±5 °С. The size of the obtained particles was determined us- ing Photocor Compact Z (Photoсor LLC, Russia). A cavi- tometer was used in order to determine the intensity of cavitation. The principle of the cavitometer is based on the analysis of cavitation noise with its conversion to an elec- tric signal. The hydrophone was placed in a treatment me- dium at a depth of 45±2 mm below the surface of the liq- uid and an electrical signal was recorded. 3. Results and discussion Cavitation is the formation of bubbles experiencing local pressure fluctuations, the occurrence of which is possible under the influence of an ultrasonic wave [13]. Cavitation measurements were carried out in the work using a cavi- tometer, the action of which is based on processing the spectrum of cavitation noise received by a broadband hy- drophone, followed by converting an acoustic signal into an electric one. The more intense the shock wave, the wid- er the spectrum of cavitation noise and the larger the elec- tric signal. The measurement of cavitation activity in the form of an electrical signal were carried out during ultra- sonic exposure of the fucoidan solution. The work revealed that cavitation activity changes un- evenly. This is because the volume fraction of the cavita- tion bubble plays an important role in cavitation. The large cavitation bubble in medium reduces acoustic trans- parency and can cause attenuation of the ultrasonic waves during their propagation [13]. However, when bubbles collapse, shock waves form, which can lead to an increase in acoustic emission. Similar dynamics of change of cavitation activity were established at the intensity of ultrasonic exposure of 100 and 133 W/cm2, as well as when used in the SDS pro- cessing medium. In addition, the amplification of the elec- tric signal was revealed when the intensity of ultrasound increased. Therefore, in the first minute, the average val- ue of this signal increased from 7.94±0.21 mV (with an ultrasound intensity of 100 W/cm2), 9.2±0.47 mV (with an ultrasound intensity of 133 W/cm2) to 10.4±1.35 mV (with an ultrasound intensity of 200 W/cm2). At higher ultra- sound power, a cone-shaped bubble structure [14] is formed which can lead to the effect of screening and scat- tering of ultrasound. This leads to a change in the shape of the acoustic emission plot compared to the acoustic emis- sion plots at lower values of sound wave intensity (Fig. 1). Application in the treatment medium (SDS) showed an increase in cavitation activity up to 14.9±0.47 mV. The use of SAA PEG-400 also led to an increase in the electric sig- nal relative to the medium without the use of SAA at the same ultrasonic wave intensity from 9.2±0.47 mV to 10.2±0.92 mV, but to a lesser extent than SDS. In general, during ultrasonic exposure, a decrease in cavitation is ob- served during the first 500 ms. When used in the SDS processing medium, there is a decrease in cavitation activity from 14.90±0.47 mV to 11.00±0.21 mV at the 30th minute of exposure (Fig. 2). It is known that SAA leads to a decrease in surface tension in liquids, as a result of which the number of collapse bub- bles decreases and they accumulate [15]. Fig. 1 Graph of the cavitation activity change at ultrasonic exposure during the first 500 ms Chimica Techno Acta 2021, vol. 8(4), № 20218414 LETTER 3 of 4 Fig. 2 Change in cavitation activity at ultrasonic exposure during 40 min when SAA is used (* – results of 5 measurements) At the same time, the introduction of SAA prevents the Bjerknes force and leads to electrostatic repulsion of cavi- tation bubbles [16], thereby their fusion is prevented, growth slows down and the lifetime of the bubbles in- creases. The retention of bubbles, in turn, can block the transmission of sound through the liquid to the hydro- phone [17], as a result of which the electrical signal is re- duced. In general, there is a decrease in cavitation activity to 9.80±0.31 mV when used in a processing medium PEG- 400 and to 14.20±0.22 mV when using SDS. SAAs have been used in the treatment environment un- der the assumption that their action caused forced con- formational changes, which are formed during the move- ment of polymer chains. In turn, this makes it possible to adopt the unwound shape of the chain and increase its sensitivity to the shear force of the shock wave when the cavitation bubble collapses [18]. Fig. 3 Dependence of size of nanoscale fraction of fucoidan on parameters of ultrasound and composition of processing envi- ronment According to Fig. 3, there is a decrease in the particle size of the polysaccharide of the nanoscale fraction of fu- coidan with an increase in the intensity of ultrasonic ex- posure. The average hydrodynamic diameter of the ob- tained particles, as in the case of molecular weight, has a certain value for a given intensity. It is known that in branched polysaccharides of the form "tangle", chain break is more difficult than in linear "stick-shaped" mac- romolecules (for example, chitosan). This is due to the fact that linear conformation leads to the accumulation of "pulling forces" throughout the entire chain [19]. It is pos- sible that this difficulty can be overcome by increasing the intensity of the ultrasonic wave or introducing PEG-400, allowing to obtain fractions with an average particle size of 85±33 and 83±25 nm, respectively. 4. Conclusions Cavitation activity in the treatment medium upon change of intensity of ultrasonic action and composition of the treatment medium was investigated. A direct proportional dependence of the ultrasound efficiency on the intensity of ultrasound wave was revealed. Similar dynamics of change of cavitation activity at intensity of ultrasonic ac- tion of 100 and 133 W/cm2 with amplification of electric signal upon the increase of ultrasound intensity was estab- lished. In such a way, with an ultrasound intensity of 200 W/cm2 the electric signal increased to 10.40±1.35 mV. The use of SDS in the processing medium led to an in- crease in cavitation activity to 14.90±0.47 mV. After 40 minutes of treatment of the fucoidan solution under vari- ous conditions, fractions with a change in average particle size from 113 nm (100 W/cm2) to 85 nm (200 W/cm2) and 124 nm (SDS) were obtained. Increasing the intensity of the ultrasonic wave or introducing PEG-400 allows obtain- ing fractions with an average particle size of 85±33 and 83±25 nm, respectively. Therefore, determination of ul- trasonic impact efficiency will allow optimizing the tech- nological process of fucoidan destructuring. Funding sources Scholarship of the President of the Russian Federation to young scientists and graduate students № SP-1758.2021.4 “Development of a nanobiocomposite tPA carrier for tar- geted high-performance thrombolytic therapy”. References 1. Wang Y, Xing M, Cao Q, Ji A, Liang H, Song S. Biological activi- ties of fucoidan and the factors mediating its therapeutic ef- fects : a review of recent studies. Mar Drugs. 2019;17:183. doi:10.3390/md17030183 2. Jin JO, Chauhan PS, Arukha AP, Chavda V, Dubey A, Yadav D. The therapeutic potential of the anticancer activity of fu- coidan: Current advances and hurdles. Mar Drugs. 2021;19:1– 17. doi:10.3390/md19050265 https://doi.org/10.3390/md17030183 https://doi.org/10.3390/md19050265 Chimica Techno Acta 2021, vol. 8(4), № 20218414 LETTER 4 of 4 3. Cui K, Tai W, Shan X, Hao J, Li G, Yu G. Structural characteri- zation and anti-thrombotic properties of fucoidan from Nema- cystus decipiens. Int J Biol Macromol. 2018;120:1817–22. doi:10.1016/j.ijbiomac.2018.09.079 4. Colliec S, Fischer AM, Tapon-Bretaudiere J, Boisson C, Durand P, Jozefonvicz J. Anticoagulant properties of a fucoidan frac- tion. Thromb Res. 1991;64:143–54. doi:10.1016/0049-3848(91)90114-C 5. Wang S, Huang C, Chen C, Chang C, Huang C, Dong C, et al. Structure and biological activity analysis of fucoidan isolated from Sargassum siliquosum. ACS omega. 2020;5:32447–55. doi:10.1021/acsomega.0c04591 6. Wang W, Wu J, Zhang X, Hao C, Zhao X, Jiao G, et al. Inhibi- tion of influenza A virus infection by fucoidan targeting viral neuraminidase and cellular EGFR pathway. Sci Rep. 2017;7:1– 14. doi:10.1038/srep40760 7. Mason J, Cuthbert C, Brookfield A. Effect of ultrasound on the degradation of aqueous native dextran. Ultrason Sonochem. 1995;2:1–3. doi:10.1038/srep40760 8. Tiwari BK, Muthukumarappan K, Donnell CPO, Cullen PJ. Rhe- ological properties of sonicated guar, xanthan and pectin dis- persions. Int J Food Prop ISSN. 2010;13:223–33. doi:10.1080/10942910802317610 9. Suslik KS, Fang M., Hyeon T, Mdleleni M. Applications of sonochemestry to materials synthesis. Sonochemistry and Sonoluminescence. 1999;291–320. 10. Mason TJ, Newman AP, Phull S. Sonochemistry in water treatment. 2nd international conference on advances in water and effluent treatment. Professional Engineering Publishing. 1993. p. 243–50. 11. Zvyagintseva TN, Shevchenko NM, Popivnich IB, Isakov V V., Scobun AS, Sundukova EV, et al. A new procedure for the sep- aration of water-soluble polysaccharides from brown sea- weeds. Carbohydr Res. 1999;322:32–9. doi:10.1016/S0008-6215(99)00206-2 12. Urvantseva AM, Bakunina IU, Kim NYU, Isakov VV, Glazunov VP, Zvyagintseva TN. Isolation of purified fucoidan from a natural complex with polyphenols and its characteristics. Chem plant raw mater. 2004;15–24. Russian. 13. Frohly J, Labouret S, Bruneel C, Looten-Baquet I, Torguet R. Ultrasonic cavitation monitoring by acoustic noise power measurement. J Acoust Soc Am. 2000;108:2012–20. doi:10.1121/1.1312360 14. Moussatov A, Granger C, Dubus B. Cone-like bubble formation in ultrasonic cavitation field. Ultrason Sonochem. 2003;10:191–5. doi:10.1016/S1350-4177(02)00152-9 15. Iwai Y, Li S. Cavitation erosion in waters having different surface tensions. Wear. 2003;254:1–9. doi:10.1016/S0043-1648(02)00305-8 16. Wood RJ, Lee J, Wood RJ, Lee J, Bussemaker MJ. A parametric review of sonochemistry : Control and augmentation of sono- chemical activity in aqueous solutions. Ultrason Sonochem. 2017;38:351–70. doi:10.1016/j.ultsonch.2017.03.030 17. Verhaagen B, Fernández Rivas D. Measuring cavitation and its cleaning effect. Ultrason Sonochem. 2016;29:619–28. doi:10.1016/j.ultsonch.2015.03.009 18. Caruso MM, Davis DA, Shen Q, Odom SA, Sottos NR, White SR, et al. Mechanically-induced сhemical changes in polymeric material. Chem Rev. 2009;109:5755–98. doi:10.1021/cr9001353 19. Czechowska-Biskup R, Rokita B, Lotfy S, Ulanski P, Rosiak JM. Degradation of chitosan and starch by 360-kHz ultrasound. Carbohydr Polym. 2005;60:175–84. doi:10.1016/j.carbpol.2004.12.001 https://doi.org/10.1016/j.ijbiomac.2018.09.079 https://doi.org/10.1016/0049-3848(91)90114-C https://doi.org/10.1021/acsomega.0c04591 https://doi.org/10.1038/srep40760 https://doi.org/10.1038/srep40760 https://doi.org/10.1080/10942910802317610 https://doi.org/10.1016/S0008-6215(99)00206-2 https://doi.org/10.1121/1.1312360 https://doi.org/10.1016/S1350-4177(02)00152-9 https://doi.org/10.1016/S0043-1648(02)00305-8 https://doi.org/10.1016/j.ultsonch.2017.03.030 https://doi.org/10.1016/j.ultsonch.2015.03.009 https://doi.org/10.1021/cr9001353 https://doi.org/10.1016/j.carbpol.2004.12.001