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Literature Review: Chitin and Chitosan From Nature to Technology

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1 Literature Review: Chitin and Chitosan From Nature to Technology
Po-Yu Chen Materials Science & Engineering University of California, San Diego May 3rd ,2006

2 Outline Introduction Production of Chitin/Chitosan
Selected Applications Chitin in Nature Conclusions

3 Chitin: a brief history
1811 Chitin was first discovered by Professor Henri Braconnot, who isolated it from mushrooms and name it “Fungine” 1823 Antoine Odier found chitin while studying beetle cuticles and named “chitin” after Greek word “chiton” (tunic, envelope) 1838 Cellulose was discovered and noted 1859 Rought discovered chitosan, a derivative of chitin.. 1920s Production of chitin fibers from different solvent systems 1930s Exploration of synthetic fibers 1950s The structure of chitin and chitosan was identified by X-ray diffraction, infrared spectra, and enzymatic analysis 1970s “Re-discovery” of the interest in chitin and chitosan 1977 1st international conference on chitin/chitosan Henri Braconnot ( ) Despite chitin is discovered earlier than cellulose, chitin receive limited attention while extensive research and development has focus on cellulose 1930s, discovery of nylon started a new era for man-made fiber/ synthetic fibers eg nylon, polyester, polypropylene, and disrupted the development of chitin fibers Muzzarelli R. et al, Chitin in Nature and Technology. Plenum Press NY, 1985

4 21st Century: New era for chitin?
Number of US patents Survey of the scientific literature Source: International conferences International Conference on Chitin and Chitosan (ICCC) International Conference of the European Chitin Society (EUCHIS) International Conference “New achievements in study of chitin and chitosan” Asia-Pacific Chitin Chitosan Symposium (APCCS) The number of chitin scientific reports since 1990 as obtained from ScienceDirect® The number of reports of 2006 is through April, 15th Source:

5 Chitin: a promising material
Unique characteristics of chitin and chitosan: Biocompatible Biodegradable Non-toxic Remarkable affinity to proteins Ability to be functionalized Renewable Abundant Muzzarelli R. et al, Chitin in Nature and Technology. Plenum Press NY, 1985

6 What is chitin? Chitin is a natural polysaccharide
1 2 3 4 5 6 Chitin is a natural polysaccharide The 2nd abundant organic source on earth Structure similar to cellulose with hydroxyl group replaced by acetamido group N-acetyl-glucosamine units in β-(1→4) linkage Chitosan is the N-deacetylated derivative of chitin N-glucosamine units in β-(1→4) linkage N-deacetylation of chitin into chitosan is achieved by treating with 50% NaOH NH2=amino group NaOH= Sodium hydroxide Polysaccharides are polymers made up of many monosaccharides joined together by glycosidic linkages Structure of Chitin, Chitosan, and Cellulose [1] [1] Kohr E. Chitin: fulfilling a biomaterials promise. Elsevier Science, 2001 [2] Images of Chitin molecules [2]

7 Chitin is a Co-polymer Pure chitin does not exist in reality
Chitin and chitosan tend to form co-polymer # of N-acetyl-glucosamine units > 50% => Chitin # of N-glucosamine units > 50% => Chitosan Degree of N-acetylation, DA = acetamido / (acetamido+amino) Degree of N-deacetylation, DD = amino / (acetamido+amino) In nature, chitin is commonly 70~90% Structure of Chitin-Chitosan co-polymer Kohr E. Chitin: fulfilling a biomaterials promise. Elsevier Science, 2001

8 Crystalline structure
Chitin has 3 polymorphic forms: α-chitin, β-chitin, γ-chitin α-chitin: the most abundant form anti-parallel configuration highly ordered crystalline structure strong H-bonding (N-H····O=C) rigid, intractable, insoluble β-chitin: - found in diatom spines and squid pens - parallel configuration weak H-bonding unstable, soluble in water γ-chitin: - mixture of α and β-chitin intermediate properties [1] H-bonding in α-chitin H-bonding in β-chitin [2] [1] Muzzarelli R. Chitin. Pergamon Press, 1977 [2] Kohr E. Chitin: fulfilling a biomaterials promise. Elsevier Science, 2001

9 Estimates of Potential Chitin Sources
1. Shellfish Sources: Resource Landings (MT) Potential waste (MT) Estimated waste (MT) Dry waste (MT) Chitin content (MT) Shrimp 2,647,345 1,058,938 710,000 177,500 44,375 Squid 1,991,094 389,219 99,531 24,882 1,244 Crabs 1,348,323 943,826 482,744 144,823 28,964 Oyster Clam 2,547,287 1,783,100 304,948 274,453 12,350 Krill 232,700 93,080 23,270 1,629 Total 8,766,749 88,652 From waste to treasure [1] 2. Fungi Sources: I has been estimated that fungi can provide metric tons chitin annually and can be potentially limitless [1] Subasinghe S. The Development of crustacean and mollusk industries. Ampnag Press (1995) 27

10 Isolation of Chitin from Shellfish and Fungi
Kohr E. Chitin: fulfilling a biomaterials promise. Elsevier Science, 2001

11 Production of Chitin Fibers
Chitin and chitosan fibers are made by the wet-spinning process: 1. Dissolve raw chitin in a solvent 2. Extrude the polymer solution through fine holes into rollers 3. Chitin in filament form can be washed, drawn, and dried Schematic presentation of typical wet-spinning production line 1. Dope tank; 2. metering pump; 3. spinneret; 4. coagulation bath; 5,6. take-up rollers; washing bath; 8. orientation bath; 9,11. stretching rollers; 10. extraction bath; ,14. advancing roller; 13. heater; 15. winder. Agboh O.C. and Qin Y. Chitin and chitosan fibers. Polymers for Advanced Technologies, 8 (1996)

12 Applications of chitin and chitosan
Crini G. Progress in Polymer Science, 30 (2005) 38 Fungicide seed coating ChitoSan® fibers and chitin socks Chitosan soap, lotion, shampoo Table. Applications of chitin, chitosan and their derivatives [1] [1] Goosen M. in Applications of Chitinand Chitosan. Technomic Publishing Inc, PA. 1997

13 Biomedical Applications
Wound Dressing Wound dressings are used to protect wound skin form insult, contamination and infection Chitin-based wound dressings - Increase dermal regeneration - Accelerate wound healing - Prevent bacteria infiltration - Avoid water loss Chitin surgical threads - strong, flexible, decompose after the heals [1] Chitosan wound dressings Anticoagulation Anticoagulation is essential for open-heart surgery and kidney dialysis Preventing blood from clotting during the surgery Sulfated chitin derivatives have good anticoagulant activity [2] Cell culture compatibility ranking of wound dressing materials [1] Kohr E. Chitin: fulfilling a biomaterials promise. Elsevier Science, 2001 [2] Khor E. Lee Y.L. Implantable applications of chitin and chtosan. Biomaterials 24 (2003) 2339

14 Biomedical Applications
Tissue Engineering Tissue engineering research is based on the seeding of cells onto porous biodegradable matrix Chitosan can be prepared in porous forms permitting cell growth into complete tissue Orthopedic Applications Porous character of chitosan scaffold [1] 50μm Bone is a composite of soft collagen and hard hydroxyapatite (HA) Chitin-based materials are suitable candidate for collagen replacement (chitin-HA composite) Mechanically flexible, enhanced bone formation Temporary artificial ligaments for the knee joint [1] Sundararajan V. et al. Porous chitosan scaffolds for tissue engineering Biomaterials 20 (1999) 1133 Ratner B.D. Biomaterials Science 2nd edition. Elsevier Science, 2004, chapter 7

15 Biomedical Applications: Drug Delivery
Hydrogels Hydrogels are highly swollen, hydrophilic polymer networks that can absorb large amounts of water pH-sensitive hydrogels have potential use in site-specific drug delivery to gastrointestinal tract (GI) Chitosan hydrogels are promising in drug delivery system Tablets Chitin and chitosan have been reported to be useful diluents in pharmaceutical preparations [1] Mechanism for pH-sensitive hydrogels Microcapsules A novel organic}inorganic composite membrane was prepared, using tetra ethyl ortho silicate (TEOS) as an inorganic material and chitosan as an organic compound. TEOS IPN swelled at pH2.5 while shrunk at pH7.5. Microcapsule is defined as a spherical empty particle with size varying from 50 nm to 2 mm Chitosan-based microcapsules are suitable for controlled drug release [2] Schematic structure of chitosan microcapsules coated with anionic polysaccharide and lipid [1] Park S.B. et al. A novel pH-sensitive membrane from chitosan — TEOS IPN. Biomaterials 22 (2001) 323 [2] Majeti N.V. Kumar R. A review of chitin and chitosan applications. Reactive & Functional Polymers 46 (2000) 1-27

16 What’s next: Biotechnology
Enzyme immobilization [1] Specific, efficient, operate at mild conditions Unstable, sensitive after isolation and purification Chitin and chitosan-based materials are suitable enzyme immobilizers - Biocompatible - Biodegradable - High affinity to protein - Reactive functional group Purves W.K. et al Life: The Science of Biology 6th edition. Sinauer Associates Inc. (2001) Gene Delivery [2] Viral gene delivery / Non-Viral gene delivery Viral: high transfection efficiency, dangerous Non-Viral: low transfection efficiency, safer Chitosan-DNA complexes can be optimized to enhance the transfection efficiency [1] Krajewska B. Application of chitin and chitosan-based materials for enzyme immobilizations Enzyme and Microbial Technology 35 (2004) 126 [2] Shi C. et al Therapeutic potential of chitosan and Its derivatives in regenerative medicine.Journal of Surgical Research (2006) In press

17 Limitations 1. High Isolation Costs Dependent on NaOH price fluctuations 2. Consistent Raw Material Supply Poor storage properties Drying reduces activity   Easily contaminated by pathogens, exotoxins 3. High Requirements for Biomedical Applications High product purity Non-toxic Good Manufacturing Practices (GMP) 4. Synthesis and Production Chitosan: $ 600/Kg (Fisher Scientific) Chitin: $ 169/Kg Ultra-pure grade chitosan: $ 40,000/Kg !! Flowchart for biomedical grade chitin products [1] [1] Kohr E. Chitin: fulfilling a biomaterials promise. Elsevier Science, 2001

18 Chitin in Nature Exoskeletons of arthropods Shells of mollusks
Spines of diatoms Cell walls of fungi, mold, yeast Other invertebrate animals

19 Chitin in Fungi Cell Walls
What are fungi? [1] Fungi have the following characteristics: Their main body is in the form of thin strands called mycelium Can not produce their own food through photosynthesis The major decomposer of organic matter Their cell walls are made mostly of chitin Chitin in fungi Fungal chitin occurs as randomly oriented microfibrils typically nm in diameter and 2~3 μm long Chitin is covalently linked to other polysaccharides, such as glucans, and forms chitin-glucan complex The chitin content in fungi varies from 0.5% in yeast to 50% on filamentous fungi species 0.1 μm SEM micrograph of chitin microfibrils (Poterioochromonas stipitata) [2] [1] Purves W.K. et al Life: The Science of Biology 6th edition. Sinauer Associates Inc. (2001) [2] Herth W. Zugenmaier P. Microbiology Letters, (1986) 263 Muzzarelli R. et al, Chitin in Nature and Technology. Plenum Press NY, 1985

20 Chitin in Mollusks Shells
The fascinating mollusk shells! Optimized material properties due to its micro- and nano-scale laminate composite structure Chitin is demonstrated in the shells of mollusk species (105 species so far) Chitin forms cross-linked chitin-protein complex and distributes mainly in the hinge and edges of the shell Bivalve mollusks deposit and orient the chitin in a very defined manner The major role of chitin: - mechanical strength - integrate the flexible region - coordinating switch during shell formation The bivalve mollusk Mytilus galloprovincials The distribution of chitin structure in mollusk shells not only count for mechanical strength but may act as coordinating switch between shell forming and cell growth and to guide the mineralization process Confocal laser scanning microscopy (LSM) image reveals a cross-linked fibrous chitin-protein matrix. The samples are labeled with chitin-binding GFP with decalcification and fixation. [1] [1] Weiss I.M. Schonitzer V. The distribution of chitin in larval shells Journal of structural biology,153 (2006) 264 Muzzarelli R. et al, Proceedings of the 1st International Conference on Chitin and Chitosan. MIT Sea Grant Program (1977)

21 Chitin in Arthropods Cuticles
What are arthropods? [1] The arthropods constitute over 90% of the animal kindom Exoskeleton composed mainly of chitin Distinct parts of the body Jointed legs and appendages Bilateral symmetry Classification of arthropods [2] Trilobites are a group of ancient marine animals Myriapods comprise millipedes and centipedes Chelicerates include spiders, mites, scorpions Hexapods comprise insects Crustaceans include crabs, lobsters, shrimps and barnacles [1] [2]

22 Arthropod cuticle: multifunctional composite
seta pore canals Epicuticle covered by a layer of wax, waterproofing barriers Exocuticle & endocuticle Main structural components of the cuticle Resist mechanical loads Multilayered chitin-protein composite embedded with minerals Exocuticle Dense, stiffer, chemically inert, and relatively dehydrated Endocuticle Sparse, softer, hydrated, and readily soluble Membrane layer Pore canals Transport mineral ions, wax, nutrition during growth Soft, ductile, can be highly deformed Typical structure of arthropod cuticle [1] exocuticle endocuticle epicuticle SEM micrograph of lobster cuticle [2] [1] Neville A. C. Biology of the Arthropod Cuticle. Springer-Verlag NY (1975) 8 [2] Rabbe D. et al. Journal of Crystal Growth 283 (2005) 1-7

23 The Hierarchical Structure of Cuticles
American lobster claw Bouligand structure bundles Helicoid stacking of the fibrous chitin-protein layers proteins chitin molecules α-chitin chains nanofibrils fibrils Rabbe D. et al. The crustacean exoskeleton as an example of a structurally and mechanically graded biological nanocomposite material Acta Materialia 53 (2005) 4281

24 The Bouligand (Twisted Plywood ) Structure
A diagram shows the parabolic patterns on the oblique surface [1] Simplified Schematic presentation of Bouligand patterns [2] Each layer corresponds to periodic 180º rotation of stacking sequence [2] Twisted plywood structure in nature Wood Crab cuticles Collagen The helicoid stacking of chitin layers shows optical illusion on the oblique surfaces 40μm 1 μm SEM photograph of chitin-protein matrix showing parabolic patterns [3] Collagen network observed in optical polarized light microscopy [3] Primary, secondary, tertiary walls of typical wood hierarchy [4] [1] Bouligand Y. Tissue & Cell 4 (1972) 189 [2] Rabbe D. et al. Acta Materialia 53 (2005) 4281 [3] Giraud-Guille M.M. Current Opinion in Soilid State and Materials Science 3 (1998) 221 [4] Vincent J.F.V Structural Biomaterials. Priceton University Press (1991) 155

25 Brittle v.s. Ductile The flat fracture surfaces of chitin bundles reveal the brittle mechanical property SEM micrograph of sheep crab Loxorhynchu grandis High density of ‘tubules’ in z-direction fail in ductile mode under tensile tractions

26 Strengthening Mechanism
Insects The most advanced development of insects is the ability to fly Insect cuticles contain mainly chitin and protein with very low mineral content The stiffening mechanism of insect cuticle is called “tanning” Tanning is due to cross-linking between proteins Crustaceans Crustacean cuticles consist of chitin, protein, and minerals, mainly CaCO3 The deposition of minerals resides in the epidermis beneath the membrane layer The mineral ions transport through pore canals and deposit in chitin-protein matrix Before molting, calcium ions can be dissolved to the environment or stored within the body (Gastrolith disk in stomach) The molting process of blue crabs Butterfly molting pupal case Simkiss K. Wilbur K.M. Biomineralization. Academic Press Inc. (1989) Warner G.F. The Biology of Crabs. Van Nostrand Reihold. (1977) Vincent J.F.V. Arthropod Structure & Development 33 (2004) 187

27 Typical Stress-Strain Curve for Chitin
The chitin samples were obtained after removing protein and inorganic mineral components Specimens were made in dumb-bell shape and tested in hydrated and dehydrated conditions Dry chitin shows a defined failure point immediately beyond the UTS; wet chitin has extensive plastic deformation beyond the UTS Dry chitin is stiff and brittle; wet chitin is more ductile The presence of water has remarkably effects on mechanical properties Mechanical properties of chitin taken from different sources Source UTS (MPa) E (MPa) ε (%) Crab Wet Dry 20 330 6.1 36 1095 3.4 Prawn Wet 13 475 2.8 21 1220 1.8 Beetle Wet 26 630 2.0 80 2900 0.6 [1] [1] [2] Typical tensile stress-train curves for wet and dry isolated crab chitin [3] [1] Hepburn H. R. et al Comparative Biochemistry and Physiology A 50 (1975) 551 [2] Joffe I. et al Comparative Biochemistry and Physiology A 50 (1975) 545 [3] Hepburn H. R. Ball A. Journal of Materials Science 8 (1973) 618

28 Typical Stress-Strain Curve for Crustacean Cuticle
A typical tensile stress-strain curve for whole crustacean cuticle shows a discontinuity in the low strain region This discontinuity is associated with the brittle failure of the inorganic mineral phase of the cuticle Brittle failure of the mineral phase occurs at low strain, leaving the chitin and protein phases to bear the load Mechanical properties of crustacean cuticle Source UTS (MPa) E (MPa) ε (%) Crab Wet Dry 23.01 ± 3.8 481 ± 75 6.3 30.14 ± 5.0 640 ± 89 3.9 Prawn Wet 28 ± 3.8 549 ± 48 6.9 29 ± 4.1 682 ± 110 4.9 [1] [1] [2] Typical tensile stress-train curves for wet and dry whole crab cuticle show low strain discontinuities [1] Hepburn H. R. et al Comparative Biochemistry and Physiology A 50 (1975) 551 [2] Joffe I. et al Comparative Biochemistry and Physiology A 50 (1975) 545

29 Mechanical Effects of Dark Pigment in Crab Cuticle
The stone crab exhibits a dark color on tips of claw and walking legs, which are exposed to higher stress and abrasive wear Vicker hardness test and three-point bending test were performed on dark and light specimens The hardness and fracture toughness for the darkened cuticle are greater than those for the light-colored cuticle The darkened cuticle has lower porosity level than light-colored cuticle Tanning (cross-linking between proteins) is the primary reason for the increased mechanical properties Dark specimen Light specimen Size of specimen: 12mm x 2mm Hardness, Fracture strength (σf), and toughness (KIC) measurements Hardness (GPa) σf (MPa) KІC (MPa·m1/2) Dark 1.33 ± 0.06 108.9 ± 22.6 2.3 ± 0.4 Light 0.48 ± 0.04 32.4 ± 23.6 1.0 ± 0.4 The stone crab Menippe mercenaria SEM photograph showing level of porosity in yellow cuticle (left) and dark cuticle (right) Melnick C. A. Chen Z. Mecholsky J. J. Journal of Materials Research 11 (1996) 2903

30 The Through-thickness Mechanical Properties of the Lobster Cuticle
Microindentation testing was conducted through the thickness of the lobster cuticle Both the hardness and the redueced stiffness show a strong discontinuity at the interface between the exocuticle and the endocuticle The exocuticle is harder and stiffer than the endocuticle exocuticle endocuticle epicuticle The American lobster H. americanus SEM micrograph shows the exocuticle has higher stacking density than the endocuticle Rabbe D. Sachs C. Romano P. Acta Materialia 53 (2005) 4281 The hardness and reduced stiffness through the thickness of the dry exoskeleton of lobster H. americanus

31 Strengthening Mechanism of Insect Cuticles
The most advanced development of insects is the ability to fly Insect cuticles contain mainly chitin and protein with very low mineral content Two stiffening mechanism of insect cuticle: “tanning” and “dehydration” Tanning is due to cross-linking between proteins Dehydration induces sufficient secondary bonds to account for the stiffness and insolubility of cuticle Stress-train curves for wet larval cuticles tanned in various concentrations of catechol for 1.5 hour Stiffness of cuticle taken before tanning from the white puparium stage, and naturally tanned E (Wet) (MPa) E (Dry) (MPa) Before tanning 74.3 ± 1.08 2200 ± 0.41 Naturally tanned 245 ± 0.15 3050 ± 0.49 Butterfly molting pupal case Dry cuticle is significantly stiffer than wet , wet tanned cuticle is significantly stiffer than untanned, but there is no much difference in stiffness between dry cuticles Vincent J.F.V. Hillerton J. E. Journal of Insect Physiology 25 (1979) 653

32 Mechanical Hysteresis of Insect Cuticles
Insect cuticles of comparably low relative stiffness are capable of work-hardening on hysteresis cycles The hysteresis is related to the arrangement of chitin fibrils with respect to the direction of the applied load Cyclic-hardening provides a fine control for instar larval growth Average tensile hysteresis behavior of eight different cuticle samples. Curves for which all points are greater than 1 exhibit cyclic-hardening; The intersegmental membrane exhibits stress-softening. [1] Typical tensile hysteresis curves for fresh silkworm cuticle showing a progressive increase in stress with additional cycles [1] 5th stage instar larva, Epiphyas postvittana [1]Hepburn H. R Chandler H. D. Journal of Insect Physiology 22 (1976) 221

33 Comparison of Cuticle with other Natural Materials
Wide range of mechanical performance of arthropod cuticle 0.3 ~ 20 GPa Wegst U.G.K Ashby M. The mechanical efficiency of natural materials Philosophical Magazine vol84 (2004) 2167

34 The Hammer of the Shrimp
The mantis shrimp use their limbs to smash hard-shelled prey The energy of a strike is about 50J They make hundreds of strikes per day, the dactyl is rarely damaged The dactyl shows an increased hardness towards outer surface The increased hardness of dactyl is due to: - Increased mineralization of cuticle - The replacement of calcium carbonate by calcium phosphate Heavily Calcified Region Chitin Fibrous Soft Tissue Dactyl Propodide ◄P:Ca► The knee of the dactyl has a thick, heavily calcified region towards the right Values for Reichardt microhardness, and values for P:Ca (multiplied by 1000). Note the high values for both variables in the outermost regions of the dactyl. The cuticle becomes much harder toward its outers surface, and this is associated with an increased mineralization of the organic cuticle Replacement of calcium carbonate by some form of calcium phosphate The smashing limb of stomatopod consists of merus, propodite, and the dactyl Relationship between microhardness and the ratio of phosphorus to calcium Currey J.D. Nash A. Bonfield W. Journal of materials science 17 (1982) 1939

35 Photonic Structures in Nature
Underside of wings. When the Morpho lands, it closes its wings showing the brown sides, which eludes their main predators, birds. Blue Morpho butterfly (Morpho menelaus) The brilliant blue butterfly can be found in the rainforests of South America (Brasil & Guyana) Why are their top wings blue? Blue color is caused by “interference” Blue light has a wavelength about 400 nm, and is interfered constructively by the slits of the morpho, which range 200 nm apart In butterflies, iridescence is caused by multiple slit interference The slits are attached to a base of melanin, a material that absorbs other light, further strengthening the blue image. If the crests and the troughs of the waves are aligned, or "in phase", they will cause constructive interference and iridescence. This happens when the one light wave hits the first groove, and a second light wave travels half of a wavelength to an other groove and is reflected back in phase with the first. If the crest of one wave meets the trough of an other wave ("out of phase"), they will cancel each other out, demising the overall light intensity. Why are their underside wings brown? The underside scales do not cause interference Brown color are produced by pigment, which is called chemical color Hierarchical structure of the wing ( wing > scales > veins > ridges) Vukusic P. Sambles J.R.Photonic structures in biology Nature 424 (2003) 852 Kertesz K. et al. Photonic crystal strucutres if biological origin Current Applied Physics 6 (2006) Source:

36 Hierarchy in Biology Characteristics: Applications:
Recurrent use of elementary units Controlled orientation Combination of hard and soft materials Sensitivity to the presence of water Multifunction Fatigue resistance Capacity for self-repair Applications: Self-assembly Functionally Gradient Materials (FGM) 3-D fibrous materials (Z-Fiber® ) Aerospace Engineering Novel composite materials increase the through-the-thickness strength of advanced composite laminates inserts small diameter composite or metal rods through the thickness of the composite item without damage FGMs are composite materials that smoothly transition from one material at one surface to another material at the opposite surface. FGM are defined as materials in which a continuous spatial change in composition or microstructure gives rise to position dependent physical and mechanical properties that can extend over microscopic or macroscopic distances Z-Fiber® is composed of hundreds of structural rods inserted through the thickness of an uncured composite structure (AZTEX Inc. Tirrell D.A. et al Hierarchical Structures in Biology as a Guide for New Materials Technology. National Academy Press. Washington D.C. (1994)

37 Conclusions Thank you! Questions?
Chitin and chitosan remain underutilized natural polymers Chitin and chitosan are promising materials for diverse applications Isolation and production need to be improved Hierarchical structures in nature are highly sophisticated, multifunctional, with unique properties Thank you! Questions?

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